Nonwoven fabric for toner seal

Abstract

The present invention is a nonwoven fabric (1) for use as a toner seal material for preventing toner leakage from the outer circumferential surface at an edge portion of a rotating body carrying powdered toner in an image forming device. The surface of the nonwoven fabric (1) has recessed portions (2) and raised portions (3) extending along the length direction (4) of the nonwoven fabric. The recessed portions (2) are groove-shaped recessed portions. The constituent fibers (6) have an average fiber diameter of 14.0 μm or less. The orientation of the constituent fibers (6) of the nonwoven fabric (1) is orthogonal or inclined with respect to the length direction (4) of the nonwoven fabric (1). The constituent fibers (6) are not heat-fused to each other. The angle of the orientation of the constituent fibers (6) with respect to the length direction (4) of the nonwoven fabric (1) is preferably 45°-135°.

Description

Nonwoven fabric for toner seals

[0001] The present invention relates to a nonwoven fabric for a toner seal, which prevents leakage of toner from the outer peripheral surface of a rotating body that carries powder toner in an electrophotographic image forming device in the axial direction of the rotating body, a method for manufacturing the same, and a toner seal material that includes the nonwoven fabric for a toner seal.

[0002] Traditionally, electrophotographic image forming devices have used powder toner as a developer. Electrophotographic image forming devices are widely used in printers, copiers, facsimile machines, and the like. In electrophotography, an electrostatic latent image is formed on an image carrier such as a photosensitive drum, developed with toner, and then transferred to a recording sheet or the like, where the toner is fixed to the recording sheet or the like. The toner is stored in a container (toner box) of the development unit and moves to the surface of the photosensitive drum or the like while adhering to the outer surface of the development roller. As the development roller or photosensitive drum rotates, the toner adheres to its outer surface. The development roller or photosensitive drum is provided with a sealant to prevent toner from leaking, for example, outward in the axial direction.

[0003] As prior art related to a sealing material for preventing leakage of fine powder or granular material, Patent Document 1 proposes a cut pile fabric including a pile that contacts the surface of a movable body and a base fabric that supports the pile. Patent Documents 2 and 3 propose the use of a nonwoven fabric as a sealing material.

[0004] Japanese Patent Application Laid-Open No. 2006-249383 Japanese Patent Application Laid-Open No. 2003-076145 Japanese Patent Application Laid-Open No. 2008-164064

[0005] However, there still remains a problem that the toner leaks from the outer circumferential surface of the rotating body that carries the powder toner in the axial direction.

[0006] In order to solve the above problems, the present invention provides a nonwoven fabric for toner seals that can effectively prevent toner leakage in the axial direction from the outer peripheral surface of a rotating body that carries powdered toner, a method for manufacturing the same, and a toner seal material that includes the nonwoven fabric for toner seals.

[0007] In one aspect, the present invention relates to a nonwoven fabric for a toner seal material used to prevent toner leakage from the outer peripheral surface at the end of a rotating body that carries powdered toner in an image forming device, wherein the surface of the nonwoven fabric has recesses and protrusions extending along the length of the nonwoven fabric, the recesses are groove-like recesses, the orientation of the constituent fibers of the nonwoven fabric is perpendicular or inclined to the length of the nonwoven fabric, the average fiber diameter of the constituent fibers is 14.0 μm or less, and the constituent fibers are not thermally fused to each other.

[0008] In one aspect, the present invention relates to a toner seal material including the nonwoven fabric for toner seals of the present invention and a cushion layer laminated on one main surface of the nonwoven fabric for toner seals, wherein the recessed portions and the protruding portions are on the surface of the nonwoven fabric for toner seals opposite the surface facing the cushion layer, and the longitudinal directions of the recessed portions and the protruding portions are aligned with the longitudinal direction of the toner seal material.

[0009] In one aspect, the present invention relates to a method for producing a nonwoven fabric for a toner seal, the method comprising the following steps A to C: A step of producing a long fiber web in which short fibers having an average fiber diameter of 14.0 μm or less are oriented in the longitudinal direction; B step of cross-lapping the fiber web to produce a long laminated web; C step of spraying a pressurized water stream from a spray nozzle along the longitudinal direction of the laminated web to form recesses and protrusions on the surface of the laminated web.

[0010] The nonwoven fabric for toner seals of the present invention is a nonwoven fabric for use in toner seal materials. The average fiber diameter of the constituent fibers is 14.0 μm or less, and the constituent fibers are not thermally fused to each other. The surface of the nonwoven fabric has concave and convex portions extending along its length. The concave portions are groove-like, so that when a toner seal material including the nonwoven fabric is attached to a rotating body, the length of the groove-like recesses is the same as the circumferential direction of the rotating body. Furthermore, the constituent fibers of the nonwoven fabric are oriented perpendicular or inclined to the length of the nonwoven fabric, so that when the toner seal material is attached to the rotating body, the constituent fibers are oriented perpendicular or inclined to the circumferential direction of the rotating body. As a result, the nonwoven fabric for toner seals of the present invention has a larger surface area facing the rotating body than nonwoven fabrics without a concave-convex structure, and because the constituent fibers are not thermally fused to each other, the surface has a larger number of pores. As a result, the pores can capture and firmly hold toner moving at the interface between the rotating body and the nonwoven fabric, preventing the toner from moving toward the ends of the rotating body. In addition, the constituent fibers, which are perpendicular or inclined relative to the circumferential direction of the rotor, prevent toner from moving toward the ends of the rotor. Therefore, by using the nonwoven fabric for toner seals of the present invention, the toner trapping rate of the toner seal material is high, and toner leakage can be effectively prevented. Furthermore, the nonwoven fabric has constituent fibers with an average fiber diameter of 14.0 μm or less, and has the recessed and protruding portions on the surface of the nonwoven fabric facing the rotor, and the length direction of the recessed portions is the same as the circumferential direction of the rotor, thereby reducing frictional resistance between the nonwoven fabric and the rotor, and is advantageous in reducing the load on the motor of an image forming device.

[0011] FIG. 1A is a schematic perspective view of a nonwoven fabric for toner seals according to one embodiment of the present invention. FIG. 1B is a schematic cross-sectional view taken along line II of FIG. 1A. FIG. 2 is a schematic explanatory view showing a step of producing a laminated web in a method for producing a nonwoven fabric for toner seals according to one embodiment of the present invention. FIG. 3 is a schematic plan view of a portion of a fiber web being folded. FIG. 4 is a schematic explanatory view showing a state in which a pressurized water stream is sprayed onto a laminated web in a method for producing a nonwoven fabric for toner seals according to one embodiment of the present invention. FIG. 5 is a schematic exploded perspective view showing a toner seal material according to one embodiment of the present invention attached to the outer peripheral surface of an end portion of a developing roller. FIG. 6A is a schematic perspective view of a toner seal material according to one embodiment of the present invention. FIG. 6B is a schematic cross-sectional view taken along line VI-VI of FIG. 6A. FIG. 7A is an enlarged planar photograph of the nonwoven fabric for toner seals according to Example 1. FIG. 7B is an enlarged cross-sectional view of the nonwoven fabric for toner seals according to Example 1, viewed in the same direction as its length.

[0012] [Nonwoven Fabric for Toner Seal] The nonwoven fabric for toner seal of the present invention (hereinafter sometimes abbreviated as "nonwoven fabric") is a nonwoven fabric constituting a toner seal material for preventing toner leakage from the outer peripheral surface of the end of a rotating body that carries powdered toner in an image forming apparatus in the axial direction of the rotating body. The surface of the nonwoven fabric has recesses and protrusions extending along its length. The recesses are groove-shaped recesses. The orientation of the constituent fibers of the nonwoven fabric is perpendicular or inclined to the length direction of the nonwoven fabric. The average fiber diameter of the constituent fibers of the nonwoven fabric is 14.0 μm or less, and the constituent fibers are not thermally fused to each other. The length direction of the nonwoven fabric is the same as the longitudinal direction of the toner seal material, and the longitudinal direction of the toner seal material is the same as the circumferential direction of the rotating body when the toner seal material is attached to the rotating body that carries powdered toner in an image forming apparatus.

[0013] The groove-like recesses can be formed by spraying a pressurized water stream onto a long laminated web. Because the spaces between the groove-like recesses become convex, the surface of the nonwoven fabric has a striped pattern with groove-like recesses and convex stripes extending in the longitudinal direction. A structure in which the constituent fibers of the nonwoven fabric are oriented perpendicular to or inclined with respect to the longitudinal direction of the sealing material can be formed by laminating the fiber web using a folding method known as cross-wrapping. Spraying a pressurized water stream onto the laminated web not only forms the groove-like recesses but also entangles the constituent fibers. This entanglement of the constituent fibers improves the integrity of the nonwoven fabric.

[0014] The phrase "orthogonal or inclined" to the longitudinal direction of the nonwoven fabric means excluding cases where the orientation of the constituent fibers of the nonwoven fabric is substantially parallel to the longitudinal direction of the nonwoven fabric, and more specifically, excludes nonwoven fabrics manufactured using parallel webs as a long laminate web. Here, "substantially parallel" not only includes cases where the orientation of the constituent fibers is completely parallel, but also cases where the angle of the orientation of the constituent fibers with respect to the longitudinal direction of the nonwoven fabric is 0 to 30 degrees.

[0015] The angle of the orientation of the constituent fibers with respect to the length direction of the nonwoven fabric (the length direction of the constituent fibers) is preferably 45° to 135°, more preferably 55° to 125°, even more preferably 65° to 115°, and even more preferably 70° to 110°. By having the orientation of the constituent fibers perpendicular to or inclined with respect to the length direction of the nonwoven fabric (the length direction of the groove-like recesses), for example, the toner trapping rate is higher than when the length direction of the groove-like recesses and the orientation of the constituent fibers are the same, and toner leakage can be effectively prevented.

[0016] The constituent fibers of the nonwoven fabric are preferably short fibers. The average fiber diameter of the constituent fibers is 14.0 μm or less, more preferably 12.5 μm or less, and even more preferably 10.0 μm or less. This is advantageous from the viewpoint of high strength, effectively preventing toner leakage, and smoothing the surface of the nonwoven fabric that contacts the rotating body, thereby reducing frictional resistance between the nonwoven fabric and the sealing material. Furthermore, the lower limit of the average fiber diameter of the constituent fibers is preferably 1.0 μm or more, more preferably 3.0 μm or more, and even more preferably 5.0 μm or more. This allows the toner to be caught and firmly held by the non-penetrating holes in the surface of the nonwoven fabric. The nonwoven fabric may contain two or more types of constituent fibers with different average fiber diameters. In this application, the average fiber diameter of the constituent fibers of the nonwoven fabric is the average value obtained by measuring the diameters of 100 randomly selected constituent fibers using a microscope (VHX-600, manufactured by Keyence Corporation).

[0017] The average fiber length of the constituent fibers is preferably 30 to 110 mm, more preferably 35 to 90 mm, and even more preferably 40 to 70 mm. This allows for efficient production of a fiber web using a standard carding machine. In this application, the average fiber length of the constituent fibers of a nonwoven fabric is the average value obtained by measuring the lengths of 100 randomly selected constituent fibers with a steel ruler.

[0018] In order to effectively prevent toner leakage, the average pitch P (see FIG. 1B) of the groove-like recesses in the width direction is preferably 0.3 to 3.0 mm, more preferably 0.6 to 2.8 mm, and even more preferably 0.7 to 2.5 mm. The pitch is the distance between the apexes of adjacent protrusions. In order to effectively prevent toner leakage, the average depth D (see FIG. 1B) of the groove-like recesses is preferably 5 to 30%, more preferably 10 to 28%, and even more preferably 10 to 25% of the average thickness H (see FIG. 1B) of the nonwoven fabric. This increases the toner trapping rate, effectively preventing toner leakage. The thickness of the nonwoven fabric is the thickness at the protrusions.

[0019] The average thickness H of the nonwoven fabric is preferably 0.3 to 3.0 mm, more preferably 0.5 to 2.0 mm, and even more preferably 0.5 to 1.5 mm, which makes it easier to incorporate the toner sealing material containing the nonwoven fabric into an image forming apparatus (printer).

[0020] In the present application, the average pitch P, average depth D, and average thickness H are each the average values ​​obtained by observing and measuring 20 randomly selected points using a microscope (VHX-600, manufactured by Keyence Corporation).

[0021] The mass per unit area of ​​the nonwoven fabric is preferably 80 to 600 g / m from the viewpoint of effectively preventing toner leakage. 2 , more preferably 100 to 500 g / m 2 , more preferably 100 to 450 g / m 2 is.

[0022] There are no particular restrictions on the material of the constituent fibers of the nonwoven fabric, but it is preferable that the nonwoven fabric contains, for example, polyester staple fibers. Polyester staple fibers have the advantage of being strong and not easily generating debris even when rubbed against a rotating body. A preferred example of polyester staple fibers is polyethylene terephthalate (PET) staple fibers. The nonwoven fabric may also contain two or more constituent fibers made of different materials.

[0023] [Method for manufacturing nonwoven fabric for toner seals] In one embodiment, the method for manufacturing a nonwoven fabric for toner seals of the present invention comprises the following steps A to C. A step of preparing a long fiber web in which short fibers having an average fiber diameter of 14.0 μm or less are oriented in the longitudinal direction; B step of cross-lapping the fiber web to prepare a long laminated web; C step of spraying a pressurized water stream from a spray nozzle along the longitudinal direction of the laminated web to form recesses and protrusions on the surface of the laminated web.

[0024] In the step A, staple fibers are opened to produce a fiber web in which the orientation (length direction) of the staple fibers is oriented in the length direction. In the step A, for example, it is efficient and preferable to open the staple fibers and align the orientation of the staple fibers using a carding machine. The mass per unit area of ​​the fiber web is 8 to 40 g / m. 2is preferred.

[0025] In step B, for example, a device called a cross wrapper is used to fold (cross wrap) the long fiber web multiple times as shown in Figure 3 to form a long laminate web (also called a cross web). An example of a method for manufacturing a cross web is disclosed in JP-A-6-116853, etc. In this laminate web, the direction (length direction) of the short fibers is perpendicular or inclined to the length direction of the laminate web.

[0026] In step C, a pressurized water stream is sprayed from a spray nozzle onto the laminated web, also known as a water jet process. This process entangles the constituent fibers and forms recesses and protrusions on the surface of the laminated web. The pressure of the water stream is preferably 0.5 to 20 MPa. Furthermore, before applying the pressurized water stream to the laminated web, it is preferable to perform a needle punching process to entangle the short fibers. This improves the handleability of the nonwoven fabric. When the short fibers are entangled by applying a pressurized water stream or needle punching, the pores of the nonwoven fabric are not reduced by thermal fusion, as occurs when the constituent fibers are bonded by a thermal bonding process, resulting in a decrease in pore size. When the short fibers are entangled by applying a pressurized water stream or needle punching, this process has the advantage of capturing toner that has migrated from the surface of the rotating body with the pores, thereby allowing the toner to be firmly retained.

[0027] The following description will be made with reference to the drawings. In the following drawings, the same reference numerals indicate the same parts. FIG. 1A is a schematic perspective view of a nonwoven fabric 1 for a toner seal according to one embodiment of the present invention, and FIG. 1B is a schematic cross-sectional view taken along line II of FIG. 1A. On one surface of this nonwoven fabric 1, recesses 2 and protrusions 3 facing in the length direction 4 are alternately repeated along the width direction 5 of the nonwoven fabric 1. The orientation (length direction) of the constituent fibers 6 is oriented in the width direction 5 of the nonwoven fabric 1. The constituent fibers 6 are also entangled, maintaining the integrity of the nonwoven fabric 1. From the viewpoint of application to a rotating body that carries powdered toner in an image forming apparatus, the nonwoven fabric 1 for a toner seal preferably has a length of 10 to 50 mm and a width of 3 to 15 mm.

[0028] Figure 2 is a schematic explanatory diagram showing the step of producing a laminated web in the method for producing a nonwoven fabric 1 for toner seals according to one embodiment of the present invention, and Figure 3 is a schematic plan view of a portion of a fibrous web during folding. In Figure 2, reference numeral 11 denotes a carding machine, to which unopened staple fibers 12 are fed from feed rollers 13a and 13b. The unopened staple fibers 12 pass through a stay-in roller 14 and are opened by the cooperation of a cylinder 15, workers 16a and 17a, and strippers 16b and 17b. The opened staple fibers 12 then pass through a doffer 18 and are stripped from the doffer 18 by a vibration comb 19, and are removed as a fibrous web 20. Reference numeral 21 denotes a base of the carding machine.

[0029] The fiber web 20 is then folded multiple times toward the front or rear side on the operating conveying means (take-off device) 23 in front view in Fig. 2 to form a long laminated web 22. More specifically, since the fiber web 20 is folded toward the front or rear side on the operating conveying means 23, a relatively upper portion of the fiber web 20 protrudes from a relatively lower portion, as shown in Fig. 3, and this is repeated multiple times to obtain a long laminated web 22 (cross web). Thereafter, the laminated web 22 may be needle-punched along its longitudinal direction to entangle the constituent fibers before applying a pressurized water stream, which will be described later.

[0030] 4 is a schematic diagram illustrating the spraying of a pressurized water stream onto a laminated web in one embodiment of the method for producing a nonwoven fabric for toner seals according to the present invention. In FIG. 4, reference numeral 24 denotes a water jet device. A pressurized water stream is sprayed from a spray nozzle 26 onto the laminated web 22 that has been unwound from a roll 25 of the laminated web 22, and the laminated web 22 is then dried in a drying device 27 and rolled up to form a roll 28. The rolled nonwoven fabric sheet preferably has a length of 10 to 100 m and a width of 30 to 240 cm, for example.

[0031] 5 is a schematic exploded perspective view showing a state in which a toner seal material containing a nonwoven fabric for toner seal according to one embodiment of the present invention is attached to the outer peripheral surface of the end of a developing roller. Toner seal materials 32a and 32b for preventing leakage of fine powder and granular material function as side seals for both end portions 33a and 33b of developing roller 33. These toner seal materials 32a and 32b are in close contact with the outer peripheral surface of developing roller 33 and are positioned to prevent toner from leaking outward in the direction of axis 34a. The developing roller 33 is attached to an opening 37 facing the developing roller 33 in a developing unit 31 of an electrophotographic image forming apparatus.

[0032] The toner seal materials 32a and 32b are attached to the housing 35 of the developing unit 31 before the developing roller 33. The developing unit 31 is also provided with a blade 36. The thickness of the toner layer is adjusted by the blade 36, which is a toner regulating member, and is kept below a certain level. The rotating shaft 34 of the developing roller 33 is rotatably supported by the housing 35 of the developing unit 31, and toner is supplied to the developing roller 33 from inside the developing unit 31.

[0033] 6, the toner seal material 32 of the present invention includes, for example, the nonwoven fabric for toner seals 1 of the present invention and a cushion layer 38 laminated on one main surface of the nonwoven fabric for toner seals 1. The cushion layer 38 contacts one of the two main surfaces of the nonwoven fabric 1 opposite the surface including the recessed portions 2 and the protruding portions 3. The nonwoven fabric 1 and the cushion layer 38 are bonded together using, for example, an adhesive. The longitudinal direction of the recessed portions 2 and the protruding portions 3 is aligned with the longitudinal direction of the toner seal material 32. From the viewpoint of application to a rotating body that carries powder toner in an image forming apparatus, the toner seal material 32 preferably has a length of 10 to 50 mm and a width of 3 to 15 mm, for example.

[0034] There are no particular limitations on the cushion layer 38, as long as it is an elastic body such as a resin sheet or a relatively elastic nonwoven fabric, etc. The cushion layer 38 is preferably a foam such as urethane foam, since it needs to be flexible enough to prevent wrinkles when the toner seal material 32 is attached to the rotating body and bent, for example, into a U-shape along the circumferential direction of the rotating body.

[0035] The thickness of the cushion layer 38 may be set in consideration of the thickness of the nonwoven fabric 1 for toner seal so that the total thickness of the toner seal material 32 is 2.0 to 5.0 mm, but is preferably 0.5 to 4.0 mm, more preferably 0.5 to 3.0 mm, and even more preferably 0.5 to 2.0 mm. This makes it easier to incorporate the toner seal material 32 into the image forming apparatus (printer).

[0036] In this specification, the upper and lower limits of each numerical range can be combined in any combination, and all such combinations are considered to be preferred numerical ranges described in this specification.

[0037] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The physical properties in the examples were measured by methods commonly used in the textile industry. The "parts" and "%" in the examples are based on mass. The following examples and comparative examples were evaluated as follows.

[0038] [Dynamic Friction Coefficient] The dynamic friction coefficient of the nonwoven fabrics for toner seals of Example 1 and Comparative Example 1 below was measured in accordance with JIS K 7125:1999. Specifically, an acrylic plate was placed on a test table with a horizontal and smooth surface, and the nonwoven fabric for toner seals, a sliding piece with felt attached to its bottom, and a weight (200 g) were placed on top of it in that order. A cable was attached to the nonwoven fabric for toner seals, and the cable was pulled horizontally with a load cell at a test speed of 100 mm / min to measure the dynamic friction coefficient.

[0039] [Toner Leakage Test] Toner seal materials with a total thickness of 3 mm were prepared by attaching a urethane foam (PORON LE20, 2 mm thick, manufactured by Inoac Corporation) as a cushion layer to one main surface of the nonwoven fabric for toner seals of Example 2 and Comparative Examples 2 to 4. Using color toner with a particle size of approximately 8 μm, the penetration rate (%) of the toner in the width direction (direction of arrow 7 in Figure 5) of the nonwoven fabric for toner seals was measured after printing 5,000 A4-sized sheets. A higher penetration rate (%) indicates a higher likelihood of toner leakage, while a lower penetration rate indicates more effective suppression of toner leakage. The penetration rate (%) of the toner is the ratio of the length of the nonwoven fabric for toner seals to the total width direction, assuming the total width direction of the nonwoven fabric for toner seals to be 100.

[0040] (Example 1) Polyethylene terephthalate (manufactured by Toray) staple fibers (staple fibers) having an average fiber diameter of 9.0 μm (fineness 0.9 decitex) and an average fiber length of 51 mm were opened using a carding machine as shown in Figure 2 to produce a long fiber web in which the PET staple fibers were oriented in the longitudinal direction. The mass per unit area (basis weight) of the fiber web was 30 g / m. 2 Next, the fiber web was cross-wrapped to produce a long laminated web (cross web). The orientation of the short fibers was 80 to 100° relative to the longitudinal direction of the laminated web. Next, as shown in Figure 4, a pressurized water stream (8 MPa) was sprayed from a spray nozzle along the longitudinal direction of the laminated web. The portions hit by the water stream formed recesses, and the portions not hit by the water stream formed protrusions. One surface of the obtained nonwoven fabric sheet was as shown in Figures 1A and 1B. The mass per unit area (basis weight) of the obtained nonwoven fabric sheet was 300 g / m 2 The thickness of the convex portions was approximately 1.0 mm, the average pitch of the concave portions in the width direction was approximately 1.5 mm, and the depth of the concave portions was approximately 200 μm. This nonwoven fabric sheet was cut into a length of 40 mm and a width of 10 mm to obtain a nonwoven fabric for a toner seal. Figure 7A shows an enlarged planar photograph (100x magnification) of the nonwoven fabric for a toner seal of Example 1, and Figure 7B shows an enlarged cross-sectional view (100x magnification) of the nonwoven fabric for a toner seal of Example 1 as viewed in the same direction as its length.

[0041] (Comparative Example 1) A nonwoven fabric sheet was produced in the same manner as in Example 1, except that polyethylene terephthalate (manufactured by Toray Industries, Inc.) staple fibers with an average fiber diameter of 14.5 μm (fineness 2.2 decitex) and an average fiber length of 51 mm were used as the short fibers. The mass per unit area (basis weight) of the fiber web was 30 g / m. 2 The orientation of the short fibers was 80 to 100° with respect to the longitudinal direction of the nonwoven fabric sheet. The mass per unit area (basis weight) of the nonwoven fabric sheet was 300 g / m 2 The thickness of the convex portions was 1.0 mm, the average pitch of the concave portions in the width direction was 1.5 mm, and the depth of the concave portions was 200 μm. This nonwoven fabric sheet was cut into a length of 40 mm and a width of 10 mm to obtain a nonwoven fabric for a toner seal.

[0042] (Example 2) A nonwoven fabric sheet was produced in the same manner as in Example 1, except that the following two types of staple fibers were used: (1) 70% by mass of polyethylene terephthalate (manufactured by Toray) staple fibers having an average fiber diameter of 9.0 μm (fineness 0.9 decitex) and an average fiber length of 51 mm; and (2) 30% by mass of heat-fusible staple fibers (core: polyethylene terephthalate, sheath: polyethylene, manufactured by Toray) having an average fiber diameter of 20.2 μm (fineness 4.4 decitex) and an average fiber length of 51 mm. The average fiber diameter of the two types of staple fibers was 12.4 μm (fineness 1.95 decitex). The mass per unit area (basis weight) of the fiber web was 30 g / m. 2 The orientation of the short fibers was 80 to 100° with respect to the longitudinal direction of the nonwoven fabric sheet. The mass per unit area (basis weight) of the nonwoven fabric sheet was 300 g / m 2 The thickness of the convex portions was 1.0 mm, the average pitch of the concave portions in the width direction was 1.5 mm, and the depth of the concave portions was 200 μm. This nonwoven fabric sheet was cut into a length of 40 mm and a width of 10 mm to obtain a nonwoven fabric for a toner seal.

[0043] (Comparative Example 2) A long laminated web (cross web) was produced in the same manner as in Example 2, using the same two types of staple fibers in the same proportions. The laminated web was then needle-punched to push some of the staple fibers into the web, and then brought into contact with a heated roll having an uneven surface to thermally fuse the heat-fusible staple fibers, thereby obtaining a nonwoven fabric sheet. The orientation of the staple fibers was 80 to 100° relative to the longitudinal direction of the nonwoven fabric sheet. The mass per unit area (basis weight) of the nonwoven fabric sheet was 300 g / m 2 The thickness of the convex portions was 1.0 mm, the average pitch of the concave portions in the width direction was 1.5 mm, and the depth of the concave portions was 250 μm. This nonwoven fabric sheet was cut into a length of 40 mm and a width of 10 mm to obtain a nonwoven fabric for a toner seal.

[0044] (Comparative Example 3) A long laminated web (cross web) was produced in the same manner as in Example 2, using the same two types of staple fibers in the same proportions. The laminated web was then needle-punched to push some of the staple fibers into the web, and then passed through a calender to smooth the surface. The orientation of the staple fibers was 80 to 100° relative to the length direction of the nonwoven fabric sheet. The mass per unit area (basis weight) of the nonwoven fabric sheet was 300 g / m 2 The nonwoven fabric sheet was cut into a length of 40 mm and a width of 10 mm to obtain a nonwoven fabric for a toner seal.

[0045] (Comparative Example 4) Using the same staple fibers as in Example 1, a fiber web was produced and wound up in the same manner as in Example 1. Next, the fiber webs were stacked in parallel to produce a long laminated web. Thereafter, as shown in Figure 4, a pressurized water stream (8 MPa) was sprayed from a spray nozzle along the length of the laminated web. The portions hit by the water stream formed depressions, and the portions not hit by the water stream formed protrusions. The orientation of the staple fibers was 0 to 10° relative to the length direction of the nonwoven fabric sheet and was substantially parallel to the length direction of the nonwoven fabric sheet. The mass per unit area (basis weight) of the nonwoven fabric sheet was 300 g / m 2The thickness of the convex portions was 1.0 mm, the average pitch of the concave portions in the width direction was 1.5 mm, and the depth of the concave portions was 200 μm. This nonwoven fabric sheet was cut into a length of 40 mm and a width of 10 mm to obtain a nonwoven fabric for a toner seal.

[0046] Table 1 below summarizes the results of evaluating the coefficient of dynamic friction and the degree of toner penetration according to the method described in the above [Toner Leakage Test] for the Examples and Comparative Examples.

[0047]

[0048] As shown in Table 1, the dynamic friction coefficients of the nonwoven fabrics for toner seals of Example 1 and Comparative Example 1 were 0.25 and 0.30, respectively. These results confirmed that the nonwoven fabric for toner seals of Example 1 had lower friction and better sliding properties than the nonwoven fabric for toner seals of Comparative Example 1, contributing to reduced motor load. It was also confirmed that toner leakage can be effectively suppressed when the average fiber diameter of the constituent fibers is 14.0 μm or less, the constituent fibers are not thermally fused to each other, the surface of the nonwoven fabric has recesses and protrusions extending along its length, the angle of the constituent fibers is perpendicular or inclined to the longitudinal direction of the groove-like recesses, and the orientation (angle) of the constituent fibers with respect to the longitudinal direction of the recesses is, for example, 45° to 135°.

[0049] The nonwoven fabric for toner seals of the present invention is useful as a material for sealing materials to prevent leakage of toner from electrophotographic image forming apparatuses that use powder toner.

[0050] REFERENCE SIGNS LIST 1 Nonwoven fabric for toner seal 2 Groove-shaped recess (recess) 3 Convex portion 4 Length direction of nonwoven fabric for toner seal 5 Width direction of nonwoven fabric for toner seal 6 Constituent fibers 11 Carding machine 12 Unopened short fibers 13a, 13b Feed roller 14 Stay-in roller 15 Cylinder 16a, 17a Worker 16b, 17b Stripper 18 Doffer 19 Vibration comb 20 Fiber web 21 Carding machine base 22 Laminated web 23 Take-up device 24 Water jet device 25, 28 Winding body 26 Spray nozzle 27 Drying device 31 Development unit 33 Development roller 32, 32a, 32b Toner seal material 33a, 33b Both ends of development roller 34 Rotation shaft 34a Axis 35 Housing 36 Blade 38 Cushion layer

Claims

1. A nonwoven fabric for a toner seal material for preventing leakage of toner from the outer peripheral surface of an end portion of a rotating body that carries powder toner in an image forming apparatus, The nonwoven fabric is formed by laminating long fiber webs in a cross-wrapped and folded state, the surface of the nonwoven fabric has recesses and protrusions extending along the length direction of the nonwoven fabric, the recesses are groove-like recesses, the average pitch of the groove-like recesses in the width direction is 0.6 to 2.8 mm, and at least some of the fibers in the groove-like recesses are entangled; The orientation of the constituent fibers of the nonwoven fabric is 65° to 115° with respect to the longitudinal direction of the nonwoven fabric, The average fiber diameter of the constituent fibers is 3.0 μm or more and 14.0 μm or less, The nonwoven fabric for a toner seal has constituent fibers that are not thermally fused together.

2. 2. The nonwoven fabric for a toner seal according to claim 1, wherein the constituent fibers include short fibers having an average fiber length of 30 to 110 mm.

3. 2. The nonwoven fabric for a toner seal according to claim 1, wherein the average depth of the groove-like recesses is 5 to 30% of the average thickness of the nonwoven fabric from the surface.

4. The mass per unit area of ​​the nonwoven fabric is 80 to 600 g / m 2 2. The nonwoven fabric for a toner seal according to claim 1, wherein

5. 2. The nonwoven fabric for a toner seal according to claim 1, wherein the thickness of the nonwoven fabric is 0.3 to 3.0 mm.

6. 2. The nonwoven fabric for a toner seal according to claim 1, wherein the nonwoven fabric is made of polyester staple fibers.

7. A toner seal material comprising the nonwoven fabric for a toner seal according to any one of claims 1 to 6 and a cushion layer laminated on one main surface of the nonwoven fabric for a toner seal, the recessed portion and the protruding portion are provided on a surface of the nonwoven fabric for a toner seal opposite to the surface on the cushion layer side, The longitudinal direction of the recessed portion and the protruding portion is aligned with the longitudinal direction of the toner seal material.

8. A method for producing the nonwoven fabric for a toner seal according to any one of claims 1 to 6, comprising the following steps A to C: A. A process for producing a long fiber web in which short fibers with an average fiber diameter of 14.0 μm or less are oriented in the longitudinal direction B. A step of cross-lapping the fiber web to prepare a continuous laminated web. C. A step of forming recesses and protrusions on the surface of the laminated web by spraying a pressurized water stream from a spray nozzle along the length direction of the laminated web.

9. The method for producing a nonwoven fabric for a toner seal according to claim 8 , wherein the laminated web is subjected to a needle punching treatment to entangle the short fibers before applying the pressurized water stream.

10. In the step B, the mass per unit area of ​​the laminated web is 80 to 600 g / m 2 The method for producing a nonwoven fabric for a toner seal according to claim 8, wherein the cross-wrapping is performed so that the cross-wrapping is performed in a manner such ...