JP2007101942A - Developer amount regulating member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developer amount regulating member which is easily managed in terms of the dimensional accuracy, easily manufactured, and also, stabilized in terms of a contact pressure, dispensing with a complicated mechanism. <P>SOLUTION: The developer amount regulating member comprises a non-rotating elastic member with a curved face and a holding member for fixing the end part of the elastic member, the curved surface of the elastic member comes in contact with a developer carrier. The curvature radius of the curved surface is within an extent of >0.5 mm and <400 mm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a developer amount regulating member used in an electrophotographic apparatus, and more particularly to a developer amount regulating member that uniformly forms a toner layer on a developing sleeve and regulates the amount of developer.

  A developing device widely used in electrophotographic technology such as a laser beam printer and a copying machine generally has a container for storing a developer and a developer carrier for discharging the developer from the developing device. On the developer carrying member, the carried-out developer plays a role of forming a uniform and thin toner layer on the developer carrying member and imparting a predetermined triboelectric charge (also called tribo) to the developer. A plate-like developer amount regulating member is generally arranged.

  The developer amount regulating member is generally composed of a plate-like rubber blade member that is in contact with the developer carrier and a plate-like metal holding member that supports the blade member at a predetermined position. An example is shown in FIG. 4 (see Patent Document 1).

  FIG. 4 is an example showing the form of a conventional developer amount regulating member. The developer regulating member 10 includes a plate-like rubber member 11 that is brought into contact with the developer carrier 100 at a contact surface 15, a plate-like metal holding member 12 that supports the plate-like rubber member 11 at a predetermined position, and a plate. And an adhesive layer 13 that adheres the plate-like rubber member 11 and the plate-like metal holding member 12 to each other. The developer regulating member 10 is in contact with the developer carrier 100 at the contact surface 15, and the developer (toner) conveyed from the developer container via the developer carrier 100 is in the region 17 (toner and frictional charging). The toner layer 14 is formed after being triboelectrically charged in the volume region). In this case, the toner and frictionally charged volume region 17 is defined by the free end side length (nip end) 16 from the end of the plate-like rubber member 11 to the contact surface 15, but the toner and frictionally charged. The size of the volume region 17, and thus the free end side length (nip end) 16, affects the process in which the developer is unloaded from the developer container and the toner layer 14 is properly formed on the developer carrier 100.

  In other words, when the length 16 on the free end side is longer than the contact surface 15, the volume of the toner and the toner that does not get on the developer carrier while being rubbed and rubbed by the frictionally charged volume region 17. The area becomes larger. Therefore, the amount of toner taken in becomes too large, or excessive toner friction due to continuous use causes toner aggregation, causing abnormal images.

  On the other hand, when the free end side length 16 is too short, there is a problem that the amount of toner taken on the developer carrier 100 is reduced. Therefore, when the developer regulating member having such a structure is adopted, the strict dimensional accuracy of the free end side length 16 is required, so that the manufacturing conditions become severe and the dimensional accuracy for obtaining a stable image is maintained. This is very difficult and contributes to a decrease in yield.

  On the other hand, as another means for forming a toner layer on a developer carrier, Patent Documents 2 and 3 disclose a technique in which a developer amount regulating member in contact with the developer carrier is formed in a roller shape. In particular, Patent Document 3 discloses a roller-shaped developer regulating member that rotates in a direction opposite to the rotation of the developer carrier. An example is shown in FIG. According to FIG. 5, the toner layer is uniformly formed on the developer carrying member while rotating the roller-shaped developer regulating member 18 in contact with the developer carrying member 100. In this case, the developer carrying member 100 and the developer restricting member 18 are driven in the reverse rotation. However, the developer restricting member 18 and the developer carrying member 100 are brought into contact with each other stably at a constant pressure. It is preferable to use a member. However, when both members are roller-shaped in this way, it is difficult to make contact with a constant pressure. For example, as a method for producing a rubber elastic member in a roller shape, there are a method of molding in a cylindrical mold, and a method of grinding rubber vulcanized by extrusion into a cylindrical shape to a predetermined dimension. When an elastic member is used, it is difficult to keep the deflection accuracy of the cylinder constant in any method. In other words, the contact pressure between the developer regulating member and the developer carrier is important for uniformly forming the toner layer on the developer carrier. Therefore, since the contact pressure varies depending on the size and accuracy, it is difficult to stably and uniformly form the toner layer with the roller-shaped developer regulating member 18. Further, according to Patent Document 3, when both the developer carrier 100 and the developer regulating member 18 are formed in a roller shape, the outer diameter changes due to environmental changes, and a spring mechanism or the like is used to absorb this change. It becomes necessary and the configuration becomes complicated.

  Further, Patent Document 4 discloses a rod-shaped member as a developer regulating member, but even in this member, in order to make the pressing proper, the number of parts for pressing pressure regulation increases, and the configuration becomes complicated.

  Further, Patent Document 5 discloses a developer regulating member 19 having a rectangular column shape or a hollow square column shape that is fitted and held in a cylindrical holding fitting portion 20. This also makes it difficult to maintain the uniformity of the toner layer formed on the developer carrier 100 depending on the dimensional accuracy of the developer regulating member 19 and the holding fitting portion 20, thereby causing image defects. End up.

  Further, examples of the shape of the developer regulating member 21 include a cylindrical shape and a hollow cylindrical shape. However, since the developer regulating member 21 has a cylindrical shape, it is driven by the rotation direction of the developer carrier 100 and is difficult to operate properly. It becomes. In addition, in order to avoid deviation around the displacement following the movement of the developer carrier and from a holding member such as the holding fitting portion 20, it is necessary to firmly fix the developer regulating member 21 and the holding fitting portion 20. . Therefore, high dimensional accuracy is required for fitting between the developer regulating member 21 and the holding fitting portion 20. Further, in order to stably hold the member for continuous use over a long period of time, it is necessary to reinforce the strong fixation by another means such as an adhesive. Thus, when the cross section of the developer amount regulating member has a circular shape, high fitting accuracy and reinforcement are provided between the developer regulating member and the holding member so as not to follow the rotation of the roller-shaped developer carrying member. Needed.

As described above, when a plate-like rubber member, a roller shape, a quadrangular prism, or a cylindrical shape is adopted as the developer amount regulating member, there are problems in each.
Japanese Patent Laid-Open No. 2-15287 JP-A-63-225267 JP 2002-268380 A Japanese Patent Laid-Open No. 2-099881 JP-A-5-011586

  The present invention has been made in view of the above-described problems. A developer amount regulating member that is easy to manage dimensional accuracy, easy to manufacture, does not require a complicated mechanism, and has a stable contact pressure. The purpose is to provide.

The developer amount regulating member according to the present invention is:
A developer amount regulating member comprising an elastic member having a curved surface that does not rotate and a holding member that fixes an end portion of the elastic member, and is in contact with the developer carrier on the curved surface,
A radius of curvature of the curved surface is in a range of more than 0.5 mm and less than 400 mm.

  According to the present invention, a uniform toner layer is formed on the developer carrying member, and a stable and good image can be obtained.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a developer amount regulating member having characteristics not conventionally obtained, such as a rubber plate shape, a driving roller shape, and a cylindrical shape. When a plate-like rubber member is used as the developer amount restricting member, the control and accuracy of the free end side length (nip end) from the contact surface of the developer amount restricting member contacting the developer carrier to the free end side are controlled. It is very difficult to secure. When the free end side length (nip end) is too long, the toner and the frictionally charged volume region between the developer amount regulating member and the cylindrical developer carrier become large. In this case, the amount of toner rubbed in this region is much larger than the amount of the toner layer 14 actually formed as a layer on the carrier, and toner deterioration due to excessive friction, melting / aggregation due to frictional heat, In addition, toner lumps are generated. As a result, image defects such as streaks are caused during image formation. On the other hand, when the free end side length (nip end) is short, the amount of the toner layer is reduced, the toner layer is insufficiently formed, and the image becomes unstable. Therefore, in order to obtain a stable image by employing this method, it is necessary to strictly control the length of the free end side (nip end) depending on the diameter of the developer carrier, the type of toner, and the application. However, in general, it is technically difficult to cut a rubber member to a desired size, resulting in poor yield and increased cost.

  Accordingly, the present inventors have invented a developer amount regulating member that is easy to manufacture and that achieves both proper toner uptake and toner layer formation.

  A developer amount regulating member according to the present invention is a developer amount regulating member that includes an elastic member having a curved surface that does not rotate and a holding member that fixes an end portion of the elastic member, and is in contact with the developer carrier on the curved surface. The curvature radius of the curved surface is in the range of more than 0.5 mm and less than 400 mm.

  FIG. 1 is a schematic view of a developer amount regulating member according to the present invention, and FIG. 2 is an explanatory view of a developer amount regulating member according to the present invention. The developer amount regulating member 103 according to the present invention includes a rubber sheet member 101 that contacts the developer carrier 100 and a holding member 102 that holds the rubber sheet member 101. The developer amount regulating member 103 according to the present invention contacts the developer carrier 100 at the contact surface 001 of the rubber sheet member 101, and the rubber sheet member 101 does not contact the developer carrier 100. The holding surface 003 holds the holding member 102. The rubber sheet member 101 and the holding member 102 may be fixed with an adhesive as necessary.

  The developer amount regulating member according to the present invention includes an elastic member having a curved surface, and the curvature radius thereof is in the range of more than 0.5 mm and less than 400 mm. When the thickness is 0.5 mm or less, it is difficult to produce each member, particularly an elastic member, and it is difficult to mount the device on an apparatus by design, and workability of fitting the elastic member and the holding member is deteriorated. On the other hand, when it is 400 mm or more, the curvature of the elastic member is close to a flat surface, and it is difficult to form a toner layer properly on the developer carrying member, and the effect of a curved surface cannot be obtained. Further, the dimension of the developer amount regulating member becomes too large, and it becomes difficult to mount it on the apparatus.

  In the developer amount regulating member according to the present invention, the member such as the rubber sheet member 101 having an abutting surface that abuts against the developer carrying member is not limited to a hollow shape, and a part of a cylinder is formed as shown in FIG. It may be held by a member such as the rubber member 104 having a part of the extracted curved surface. Further, in the rubber member 104 having a part of the curved surface, the other part may have any shape as long as only the contact part has a shape in which a part of the cylinder is extracted. In this case, the holding member may be U-shaped as indicated by 105 or may be planar as indicated by 106. Adhesion may be performed on a surface parallel to the contact surface, or a flat surface may be provided on the extended line of the curved surface.

  As described above, the developer amount regulating member according to the present invention may have a shape in which a rubber sheet member 101 obtained by bending a sheet-shaped rubber member and a holding member 102 are combined. Moreover, the shape which combined the rubber member 104 which has a part of curved surface, and U shape like 105, or planar shape like 106 may be sufficient. Further, there are a combination of a rubber sheet member 101 obtained by bending a sheet-shaped rubber member and a flat plate holding member such as 106, or a shape in which a curved rubber member and a flat plate holding member 106 are integrally formed. May be.

  The shape of 102, 105, 106, etc. shown in FIGS. 1 to 3 is an example, and the abutting surface is a curved surface, and the shape of other surfaces can be held at least, and the entire surface can be held. As long as the member does not roll, any shape may be used. When the developer amount regulating member according to the present invention is incorporated in the developing device, the member shape may be arbitrarily added according to the device. For example, the flat plate may be extended, a screw hole may be formed, or bending processing may be performed in consideration of interference with surrounding members. Further, it may be integrated with the developing device. Therefore, the versatility in design is high.

  The developer amount regulating member 103 according to the present invention is brought into contact with the developer carrying member 100 during operation of the developing device. This contact force is transmitted to the non-contact surface 002 through the holding surface 003, and the contact is made. It extends from the contact surface 001 to the developer carrier 100. The direction of this stress does not go against the holding force of the rubber sheet member 101 by the holding member 102. Therefore, the developer amount regulating member 103 according to the present invention is not affected by the stress that can be received during operation of the developing device.

  Further, the developer amount regulating member 103 according to the present invention can reduce the usage amount of the rubber sheet member 101 as compared with the example shown in FIG. As a result, the developer amount regulating member according to the present invention is less susceptible to the influence caused by the specific environmental change of the elastic member than in the past.

  Further, the developer amount regulating member according to the present invention is not rotated by the rotation of the developer carrier 100 because the rubber sheet member 101 is fixed through the holding member 102 fixed to the apparatus to be introduced during operation. . Therefore, the management of the surface accuracy of the rubber sheet member 101 is easy.

  In addition, the developer amount regulating member according to the present invention forms a toner layer on the developer carrier 100 without rotating as the developer carrier rotates as in the conventional example. Unaffected by runout accuracy. As a result, the toner layer can always be properly regulated without causing unevenness in the contact pressure.

  Further, the developer amount regulating member according to the present invention holds the rubber sheet member 101 and the holding member 102 in a fixed positional relationship, so that the toner formed with the developer carrier 100 is rubbed even during operation. The area to be charged can be easily adjusted to the desired range. Therefore, the chargeability is kept uniform and contributes to the formation of a good image.

  From the above, the developer amount regulating member according to the present invention has a simple structure, easy accuracy control, and can form a uniform toner layer on the developer carrying member.

  In the developer amount regulating member according to the present invention, the elastic member constituting the contact surface is not particularly limited as long as it has elasticity. For example, polyurethane, silicone rubber, natural rubber, NBR, EPDM, polyethylene, polyester, polypropylene and the like can be mentioned, and these may be used alone or in combination. Among these, the elastic member is preferably polyurethane in terms of wear resistance.

In particular, when polyurethane is used as the material for the rubber sheet member, from the ease of production,
A prepolymer obtained by partially polymerizing polyisocyanate and polyol, and a low molecular weight dihydric alcohol and a trihydric or higher polyhydric alcohol as a curing agent are preferably produced by thermal curing.

  Examples of polyisocyanates include 4,4'-diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (H-MDI), trimethylhexamethylene diisocyanate (TMHDI), and tolylene diisocyanate. (TDI), carbodiimide-modified MDI, polymethylene phenyl polyisocyanate, orthotoluidine isocyanate (TODI), naphthylene diisocyanate (NDI), xylene diisocyanate (XDI), hexamethylene diisocyanate (HDI), paraphenylene diisocyanate (PDI), lysine diisocyanate Examples include methyl ester (LDI) and dimethyl diisocyanate. These may be used alone or in combination of two or more.

  Examples of the polyol include polyether polyols such as polycaprolactone, polyoxytramethylene glycol, polyoxytetramethylene glycol, and polyoxypropylene glycol. Of these, those having a molecular weight of about 1000 to 3000 are preferably used. If it is less than 1000, the physical properties of the resulting urethane rubber tend to decrease, and if it exceeds 3000, the prepolymer viscosity increases, and the molding workability tends to be remarkably deteriorated. The polyurethane raw material may be a polyether type, a polyester type, or a combination thereof.

  As the above-mentioned curing agent, a low molecular weight dihydric alcohol having a molecular weight of 300 or less or a trihydric or higher polyhydric alcohol is used in combination. Examples of low molecular weight bifunctional alcohols include, for example, ethylene glycol (EG), diethylene glycol (DEG), propylene glycol (PG), 1,4-butanediol (BD), hexanediol, 1,4-hexanediol (HD), etc. Is mentioned. Examples of the tri- or higher functional alcohol include glycerin, 1,2,4-butanetriol, trimethylolethane (TME), trimethylolpropane (TMP), 1,2,6-hexanetriol, and the like. In the present invention, it is preferable to use a mixture of two or more of these curing agents.

  Polyisocyanate and high molecular weight polyol may be used respectively, or may be reacted in advance under isocyanate-rich conditions and used as a prepolymer. In the present invention, it is easier to use the prepolymer method because the molding reaction is easily controlled in the mold.

  Further, the amount of the high-molecular-weight polyol, chain extender, etc., used for the polyisocyanate is suitably 0.3 to 1.0 mole as active hydrogen per mole of isocyanate group, preferably 0.6. It is the quantity which becomes -0.95 mol.

  Examples of the catalyst include metal catalysts such as dibutyltin dilaurate and stannous octoate, and tertiary amine catalysts such as tetraethylenediamine, triethylamine and diazabicyclooctane, which are used alone or in combination. The amount used is appropriately selected depending on the raw material polyisocyanate, the high molecular weight polyol, and the amount ratio thereof, but it is usually 50 to 5000 ppm relative to the polyurethane raw material.

  In addition, what is necessary is just to shape | mold the elastic member of this invention by the method well-known in this technical field, for example, injection molding, extrusion molding, centrifugal molding etc. are mentioned. In the case of centrifugal molding, a molding die having a diameter of 30 cm to 80 cm may be used, and the molding may be performed at a rotational speed of 500 to 2000 rpm, a temperature of 110 to 160 ° C., and a reaction time of 30 to 60 minutes.

  Furthermore, the elastic member preferably has a hardness of 45 ° or more and 95 ° or less. If it is less than 40 °, it is too soft to keep its shape as a sliding part, and it will fall off and deform. On the other hand, when the angle exceeds 95 °, the method of bending and holding the sheet as an example of the present invention cannot be taken, and further, the developer carrier is worn and scratched due to being too hard. In addition, hardness says the hardness according to JISA hardness (JIS K6253).

  The surface of the rubber sheet member with which the developer amount regulating member according to the present invention abuts against the developer carrying member may be surface-treated according to the use of the developer amount regulating member. For example, when the purpose is to reduce friction, as this surface treatment, a method of impregnating polyurethane with an isocyanate compound or the like to cause a partial chemical reaction, a method of forming a two-layer structure, a method of applying a lubricant, silicone, Examples thereof include a method of mixing with a fluoride, a method of mixing a lubricating resin, and a method of treating the surface with UV / EB / plasma treatment / corona discharge. The manufacturing methods given in the examples described later have no problems in combination with these methods, and can be combined with these techniques.

  Furthermore, the surface roughness (Rz) of the surface of the rubber sheet member with which the developer amount regulating member according to the present invention abuts against the developer carrying member is more preferably 0.5 to 20 μm. If Rz is less than 0.5, the developer is insufficiently frictionally charged, which causes image unevenness called ghost. If it exceeds 20 μm, toner slips out. In addition, surface roughness (Rz) says the measured value according to JISB0601.

  The elastomer physical property of the material used for the elastic member is preferably such that the peak temperature Tg of tan δ is outside the use range of the developer amount regulating member according to the present invention, specifically 15 ° C. or less, preferably 0 ° C. or less. is there.

  The developer amount regulating member according to the present invention preferably has a resilience of 10% or more. The developer amount regulating member according to the present invention abuts against the developer carrying member and is pressed with a constant pressing pressure to regulate the amount of the developer. I can't get it. The resilience modulus was measured according to JIS K6255 (Rebound resilience test method for vulcanized rubber and thermoplastic rubber).

  Next, a method for producing the rubber sheet member and the image agent amount regulating member in the present invention will be described.

Example 1
75:25 of polyurethane prepolymer pre-heated to 80 ° C. (prepolymer made of MDI and PTG-1500 and prepared with NCO% of 5.0%), 1,4-butanediol and trimethylolpropane A curing agent having a weight ratio of 1000 ppm of TEDA (tetraethylenediamine) was mixed so that the molar ratio of hydroxyl groups to isocyanate groups was 0.9 and heated to 130 ° C. Thereafter, it was put into a centrifugal molding machine and cured at a rotation of 900 rpm for 45 minutes to obtain a polyurethane sheet. The input amount at this time was a sheet thickness equivalent to 0.5 mm. After completion of the reaction, a cylindrical polyurethane molded product was taken out from the centrifugal molding machine, and a sheet member was cut out. Thereafter, aging was performed for 1 day under conditions of 23 ° C. and 60%.

  The polyurethane sheet which passed through the aging process was cut into a size of 15 mm × 230 mm × 0.5 mm to obtain a strip-shaped sheet.

  On the other hand, a holding member was produced by the following method. A 10 mm × 10 mm × 230 mm square bar made of ABS is prepared, and a groove of 6 mm (horizontal width) × 4 mm (depth) is formed on the cross section of 10 mm × 10 mm to form a U-shape, and the holding member 102 Was made.

  A rubber sheet member 101 having a curved 15 mm side of the strip-shaped sheet formed as described above was fitted into the holding member 102 to form a developer amount regulating member 103. The curvature radius of the developer amount regulating member 103 was 3 mm.

  As an actual machine evaluation, HEWLETT PACKARD Laser Jet4000 was remodeled and replaced with a developer amount regulating blade in this evaluation.

(Example 2)
A rubber member 104 having a part of a curved surface made of the same material as in Example 1 was held by a flat holding member 106 to form a developer amount regulating member. The material and shape were the same as in Example 1, and members were obtained by in-mold molding and the same evaluation experiment was performed.

(Comparative Example 1)
A sheet was made of the same material as in Example 1, and joined to a plate-shaped metal holding member to form a developer amount regulating member. The length on the free end side from the contact portion at this time was set to 2 mm.

(Comparative Example 2)
Similar to Comparative Example 1, the free end side length was 0.2 mm.

(Comparative Example 3)
The same material as in Example 1 was formed into a cylindrical shape with a radius of 3 mm in the mold and fitted into the same holding member to form a developer amount regulating member.

(Comparative Example 4)
The same one as in Example 1 was produced with a radius of curvature equivalent to 0.5 mm.

(Comparative Example 5)
The same one as in Example 1 was produced with a curvature radius equivalent to 400 mm.

  These results are shown in Table 1. In this way, a developer amount regulating member having good characteristics was obtained by making the non-cylindrical shape only the abutting portion a part of the curved surface and holding it by the non-abutting portion. However, the radius of curvature must be in the range of more than 0.5 mm and less than 400 mm. If it is in this range, it can be easily manufactured and evaluated, but good results are obtained for those outside this range. There wasn't.

FIG. 3 is a schematic view of a developer amount regulating member according to the present invention. It is explanatory drawing of the developer amount control member by this invention. 6 is another embodiment of a developer amount regulating member according to the present invention. It is an example which shows the form of the conventional developer amount control member. It is another example which shows the form of the conventional developer amount control member.

Explanation of symbols

001 Contact surface 002 Non-contact surface 003 Holding surface 10 Developer regulating member 11 Plate rubber member 12 Plate metal holding member 13 Adhesive layer 14 Toner layer 15 Contact surface 16 Free end side length (nip end)
17 Toner and frictionally charged volume region 18 Developer restricting member 19 Developer restricting member 20 Holding fitting portion 21 Developer restricting member 100 Developer carrying member 101 Rubber sheet member 102 Holding member 103 Developer amount restricting member 104 One surface of curved surface Rubber member having a portion 105 holding member 106 flat plate holding member

Claims (6)

A developer amount regulating member comprising an elastic member having a curved surface that does not rotate and a holding member that fixes an end portion of the elastic member, and is in contact with the developer carrier on the curved surface,
The developer amount regulating member, wherein a curvature radius of the curved surface is in a range of more than 0.5 mm and less than 400 mm.   The developer amount regulating member according to claim 1, wherein the elastic member has a plate shape.   The developer amount regulating member according to claim 1, wherein the elastic member has a shape of a part of a cylinder.   The developer amount regulating member according to claim 1, wherein a space is provided between the elastic member and the holding member.   The developer amount regulating member according to claim 1, wherein there is no space between the elastic member and the holding member.   The developer amount regulating member according to any one of claims 1 to 5, wherein the elastic member is polyurethane.

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