Cleaning device

Abstract

This cleaning device is provided with a plate-shaped cleaning blade that includes a tip section that makes contact with an object, and a support member that supports the cleaning blade, wherein a displacement amount, which is the distance between the position of the tip section in a state in which the rotation of the object is stopped and the position of the tip section in a state in which the object is rotating, is 32 μm or less.

Description

cleaning device

[0001] The present invention relates to a cleaning device used in electrophotographic image formation.

[0002] In an electrophotographic image forming apparatus, a cleaning device is installed to remove toner remaining on the surface of a photosensitive drum. Japanese Patent Application Laid-Open No. 2006-207462 discloses a structure in which a flat elastic member (cleaning blade) is fixed to a support member.

[0003] International Publication No. 2022 / 138076

[0004] Since the photosensitive drum rotates with the tip of the cleaning blade in contact with the photosensitive drum, the tip wears over time in conjunction with the rotation of the photosensitive drum. While the above description focuses on the photosensitive drum for convenience, similar issues are anticipated in any structure in which a member rotates with the cleaning blade in contact. In consideration of the above circumstances, one aspect of the present disclosure aims to suppress wear of the tip of the cleaning blade.

[0005] In order to solve the above problems, a cleaning device according to one aspect of the present disclosure includes a plate-shaped cleaning blade including a tip that contacts an object, and a support member that supports the cleaning blade, and the displacement amount, which is the distance between the position of the tip when the object is stopped from rotating and the position of the tip when the object is rotating, is 32 μm or less.

[0006] FIG. 1 is a configuration diagram of an image forming apparatus according to an embodiment; FIG. 2 is a cross-sectional view of a cleaning device; FIG. 3 is an explanatory diagram relating to the angle of the tip of a cleaning blade; FIG. 4 is a material composition of each sample; FIG. 5 is an explanatory diagram of a method for measuring the displacement amount of the tip; FIG. 6 is a graph showing the results of measuring the displacement amount of the tip; FIG. 7 is an explanatory diagram of a method for measuring the wear amount of the tip; FIG. 8 is a result of measuring the 100% modulus, the displacement amount, and the wear amount for each sample; and FIG. 9 is a scatter diagram showing the relationship between the displacement amount and the wear amount for each sample.

[0007] The embodiments for carrying out the present disclosure will be described with reference to the drawings. Note that the dimensions and scale of each element in each drawing may differ from those of the actual product. Furthermore, the embodiment described below is an exemplary embodiment that may be envisioned when carrying out the present disclosure. Therefore, the scope of the present disclosure is not limited to the embodiment exemplified below.

[0008] 1 is a configuration diagram of an image forming apparatus 100 according to one embodiment of the present disclosure. The image forming apparatus 100 is an electrophotographic printing apparatus (e.g., a multifunction peripheral) that forms an image on a sheet-like recording medium 200 such as printing paper, and includes a photosensitive drum 11, a charging roll 12, an exposure device 13, a supply roll 14, a developing roll 15, a transfer roll 16, a fixing roll 17, and a cleaning device 18.

[0009] The photosensitive drum 11 is a cylindrical photosensitive body whose outer circumferential surface is made of a photosensitive material. The charging roll 12 is a conductive roll that uniformly charges the surface of the photosensitive drum 11. The exposure device 13 forms an electrostatic latent image by exposing the photosensitive drum 11 to light. The supply roll 14 supplies charged toner to the surface of the developing roll 15. The developing roll 15 adheres the toner to the electrostatic latent image on the surface of the photosensitive drum 11. The transfer roll 16 transfers the toner adhered to the surface of the photosensitive drum 11 to the recording medium 200. The fixing roll 17 fixes the toner transferred to the surface of the recording medium 200. The cleaning device 18 removes any toner remaining on the surface of the photosensitive drum 11.

[0010] 2 is a cross-sectional view of the cleaning device 18. The cleaning device 18 is a structure that is elongated in the direction of the rotation axis of the photosensitive drum 11 (i.e., the direction perpendicular to the paper surface of FIG. 2 ). As illustrated in FIGS. 1 and 2 , the cleaning device 18 includes a support member 20 and a cleaning blade 30.

[0011] The support member 20 is a plate-shaped structure (holder, bracket) that supports the cleaning blade 30. The material of the support member 20 is arbitrary, but a highly rigid metal material such as a zinc-plated steel plate is exemplified as a main material of the support member 20.

[0012] The cleaning blade 30 is a plate-like elastic member including a tip portion 36. Specifically, the cleaning blade 30 is a plate-like member having a predetermined thickness (e.g., about 2 mm) and shaped into a long rectangle in the direction of the rotation axis of the photosensitive drum 11. The cleaning blade 30 is fixed to the support member 20 by, for example, an adhesive.

[0013] The tip portion 36 is the edge that contacts the surface of the photosensitive drum 11. Specifically, the cleaning blade 30 includes a first surface 31 and a second surface 32. The first surface 31 is the main surface that faces the photosensitive drum 11. The second surface 32 is a side surface that constitutes the tip surface of the cleaning blade 30. The tip portion 36 is the portion where the first surface 31 and the second surface 32 intersect. The angle α of the tip portion 36 is the angle formed by the first surface 31 and the second surface 32. In the following description, attention will be focused on the angle α when the tip portion 36 is not in contact with the photosensitive drum 11.

[0014] 3 is an explanatory diagram of the angle α. The angle α is the angle between a line segment L1 along the first surface 31 and a line segment L2 along the second surface 32. The line segments L1 and L2 are, for example, 100 μm long. The line segment L1 is a virtual line segment that approximates the first surface 31 in the cross section of the cleaning blade 30, and the line segment L2 is a virtual line segment that approximates the second surface 32 in the cross section.

[0015] As the photosensitive drum 11 rotates (i.e., slides) with the tip 36 in contact with the surface of the photosensitive drum 11, the tip 36 wears over time. It is important for the cleaning device 18 to suppress the amount of wear of the tip 36. To suppress wear of the tip 36, the inventors of the present application measured various characteristics of multiple cleaning blade 30 samples (examples and comparative examples). Figure 4 shows the material composition of each sample. Each value in Figure 4 represents the weight part of each constituent material when the weight of the base material (specifically, polyol) of the cleaning blade 30 is taken as 100.

[0016] Each sample was made of polyurethane. Material composition A used "Kuraray Polyol O-2010" (molecular weight 2000) manufactured by Kuraray Co., Ltd. as the polyurethane polyol, while material compositions B to I used "POLYLITE CT-4117" (molecular weight 2000) manufactured by DIC Corporation. The isocyanate used in the polyurethane was 4,4'-diphenylmethane diisocyanate (MDI). Specifically, "MILLIONATE MT" manufactured by Tosoh Corporation was used as the isocyanate.

[0017] In material compositions A to C and I, trimethylolethane (TME) manufactured by Koei Chemical Industry Co., Ltd. was used as the crosslinking agent, and 1,3-propanediol (1,3PD) manufactured by Mitsubishi Chemical Corporation was used as the chain extender. In material compositions D to H, trimethylolpropane (TMP) manufactured by Perstorp Japan Co., Ltd. was used as the crosslinking agent, and 1,4-butanediol (1,4BD) manufactured by Mitsubishi Chemical Corporation was used as the chain extender.

[0018] For multiple samples with different combinations of the material composition and the angle α of the tip portion 36 described above, (1) the 100% modulus in a 23°C environment, (2) the displacement of the tip portion 36, and (3) the wear amount of the tip portion 36 were measured. Each sample had a total length of 50 mm and a thickness of 2 mm. The free length of each sample was 9 mm. As illustrated in FIG. 2 , the free length is the length of the portion of the cleaning blade 30 that protrudes from the end 21 of the support member 20 (hereinafter referred to as the "protrusion 33"). In other words, the protrusion 33 is a portion that elastically deforms in conjunction with the rotation of the photosensitive drum 11.

[0019] The 100% modulus is an index of the hardness of the cleaning blade 30. Specifically, the 100% modulus is the tensile stress (MPa) required to impart 100% elongation to the cleaning blade 30. Specifically, the 100% modulus of each sample was measured in an environment of 23°C temperature in accordance with Japanese Industrial Standards (JIS) K6251 (2017) "Vulcanized rubber and thermoplastic rubber - Determination of tensile properties."

[0020] The displacement amount is the distance (movement amount) that the leading end 36 is displaced when the photosensitive drum 11 rotates. Specifically, the displacement amount of the leading end 36 of each sample was measured using a pseudo photosensitive body 50 and an imaging device 55, as shown in FIG.

[0021] The pseudo photoreceptor 50 is a cylindrical structure simulating the photoreceptor drum 11. Specifically, the pseudo photoreceptor 50 was created by forming a polycarbonate film 52 on the outer peripheral surface of a glass cylindrical member 51 having a diameter of 40 mm. A lubricant was applied to the outer peripheral surface of the pseudo photoreceptor 50. Specifically, "HYLAR301F" (PVDF: Polyvinylidene Difluoride) manufactured by Solvay Japan Co., Ltd. was used as the lubricant. The amount of lubricant applied was 0.1 mg.

[0022] The contact angle of the cleaning blade 30 with respect to the surface of the pseudo-photoreceptor 50 was 20°. The cleaning blade 30 was installed so that the load from the cleaning blade 30 to the surface of the pseudo-photoreceptor 50 was 0.18 N / cm. The temperature of the measurement environment was 23°C, and the humidity (relative humidity) was 55%.

[0023] In the above environment, the pseudo photoreceptor 50 was rotated with the tip 36 of the sample in contact with the outer peripheral surface of the pseudo photoreceptor 50, and the image of the tip 36 was captured from inside the pseudo photoreceptor 50 using the imaging device 55, thereby measuring the displacement of the tip 36. The rotation speed of the pseudo photoreceptor 50 was 460 mm / sec. The imaging device 55 was a CCD (Charge-Coupled Device) camera installed inside the pseudo photoreceptor 50. Specifically, a dot-like index was added to the tip 36, and the movement of the index on the tip 36 was analyzed by analyzing the image captured by the imaging device 55.

[0024] FIG. 6 is a graph showing the change over time in the displacement of the tip portion 36 in response to the rotation of the quasi-photosensitive element 50. At time T0 in FIG. 6, rotation of the quasi-photosensitive element 50 began. As can be seen from FIG. 6, the displacement of the tip portion 36 reached a maximum immediately after the quasi-photosensitive element 50 began to rotate, and thereafter periodically fluctuated with a small amplitude. The distance between the position of the tip portion 36 when the quasi-photosensitive element 50 was stopped and the position of the tip portion 36 when the quasi-photosensitive element 50 was rotating (specifically, the state in which the displacement reached a maximum immediately after the start of rotation) was measured as the displacement of the tip portion 36. As can be seen from FIG. 6, the displacement of the tip portion 36 reached a maximum immediately after the quasi-photosensitive element 50 began to rotate, and therefore the measurement result can also be expressed as the maximum value of the displacement of the tip portion 36.

[0025] The amount of wear is an index of the degree to which the tip portion 36 is worn due to friction with the rotating photoreceptor drum 11. The amount of wear of each sample was measured using a pseudo photoreceptor 60, as illustrated in FIG.

[0026] The pseudo photoreceptor 60 is a cylindrical structure that simulates the photoreceptor drum 11. Specifically, the pseudo photoreceptor 60 was created by covering the surface of a rotatable cylinder 61 with an abrasive film 62. The abrasive film 62 is an abrasive material for promoting wear of the tip portion 36. Specifically, "Lapping Film Abrasive #15000 A3-0.3 SHT" manufactured by 3M Japan Ltd. was used as the abrasive film 62. The surface roughness of the abrasive film 62 was 0.3 μm.

[0027] The contact angle of the cleaning blade 30 with respect to the surface of the pseudo-photoreceptor 60 was 20°. The cleaning blade 30 was installed so that the load from the cleaning blade 30 to the surface of the pseudo-photoreceptor 60 was 0.18 N / cm. The temperature of the measurement environment was 23°C, and the humidity (relative humidity) was 55%.

[0028] In the above environment, the pseudo photoreceptor 60 was rotated with the tip 36 of the sample in contact with the outer peripheral surface of the pseudo photoreceptor 60, and the amount of wear was measured when the sample was slid a predetermined sliding distance against the pseudo photoreceptor 60. Specifically, the tip 36 after the test was imaged with an imaging device (not shown), and the area of ​​the worn portion where wear occurred was calculated as the amount of wear. The sliding distance was a distance equivalent to five sheets of A4 portrait-sized printing paper, and the rotation speed of the pseudo photoreceptor 50 was 460 mm / sec.

[0029] Figure 8 shows the results of measuring the 100% modulus, displacement, and wear for each of several samples (Comparative Examples 1 to 8 and Examples 1 to 13) with different combinations of material composition and angle α. The 100% modulus values ​​are the same for samples with the same material composition. Figure 9 is a scatter plot showing the relationship between displacement and wear for each sample.

[0030] In Comparative Examples 1 to 8, the angle α of the tip portion 36 is 90°. On the other hand, the angle α in Examples 1 to 13 is an obtuse angle (90°<α<180°). As can be seen from FIGS. 9 and 10 , the displacement amount is suppressed in Examples 1 to 13 compared to Comparative Examples 1 to 8. Specifically, the displacement amount exceeds 32 μm in Comparative Examples 1 to 8, whereas the displacement amount is suppressed to 32 μm or less in Examples 1 to 13. Note that although FIG. 2 illustrates an example in which the cross-sectional shape of the cleaning blade 30 is a parallelogram, the planar shape of the cleaning blade 30 is arbitrary.

[0031] As can be seen from Figure 9, there is a tendency that the smaller the displacement of the tip portion 36, the smaller the amount of wear of the tip portion 36. According to Examples 1 to 13 in which the amount of displacement was suppressed to 32 μm or less, the amount of wear of the tip portion 36 was 46 μm. ２ Considering the results of the measurements described above, from the viewpoint of suppressing the amount of wear of the tip portion 36, it is preferable that the amount of displacement of the tip portion 36 during rotation of the photosensitive drum 11 is 32 μm or less. In a more preferable embodiment, the amount of displacement of the tip portion 36 is 28 μm or less.

[0032] 8 and 9, in Examples 1 to 13 in which the angle α of the tip portion 36 is 92° or greater, the amount of displacement is suppressed to 32 μm or less. Therefore, a configuration in which the angle α of the tip portion 36 is 92° or greater is preferable. More preferably, the angle α of the tip portion 36 is set to 95° or greater.

[0033] As described above, from the viewpoint of suppressing the amount of displacement, a configuration in which the angle α of the tip portion 36 is large is preferable. However, if the angle α is excessively large, the area of ​​the second surface 32 becomes large, and it becomes difficult to maintain the second surface 32, which is the cut surface, as a highly flat surface in the process of manufacturing the cleaning blade 30 by cutting a large elastic substrate. From the viewpoint of maintaining the second surface 32 as a highly flat surface, a configuration in which the angle α of the tip portion 36 is 110° or less is preferable. More preferably, the angle α of the tip portion 36 is set to 105° or less.

[0034] As described above, in a preferred aspect of the present disclosure, the angle α of the tip portion 36 is equal to or greater than 92° and equal to or less than 110°. In an even more preferred aspect, the angle α of the tip portion 36 is equal to or greater than 95° and equal to or less than 105°. According to the above aspect, it is possible to both suppress wear of the tip portion 36 and maintain the second surface 32 as a highly accurate flat surface.

[0035] 8 and 9, the displacement is suppressed to 32 μm or less in Examples 1 to 13 in which the 100% modulus in an environment of 5.3 MPa or more in a 23° C. environment. Therefore, it is preferable that the 100% modulus of the cleaning blade 30 in an environment of 23° C. is 5.3 MPa or more.

[0036] As described above, from the viewpoint of suppressing the amount of displacement, it is preferable that the 100% modulus of the tip portion 36 is large in an environment of 23° C. However, if the 100% modulus is excessively large, the tip portion 36 becomes very hard, and as a result, the surface of the photosensitive drum 11 may be worn due to sliding of the tip portion 36. From the viewpoint of suppressing wear on the surface of the photosensitive drum 11, it is preferable that the 100% modulus of the tip portion 36 in an environment of 13.6 MPa or less.

[0037] As described above, in a preferred embodiment of the present disclosure, the 100% modulus of the cleaning blade 30 in an environment of 23° C. is 5.3 MPa or more and 13.6 MPa or less. According to the above embodiment, it is possible to suppress both wear of the tip portion 36 and wear of the photosensitive drum 11.

[0038] As described above, according to this embodiment, the displacement of the tip 36 of the cleaning blade 30 during rotation of the photosensitive drum is 32 μm or less, so wear of the tip 36 can be effectively suppressed.

[0039] In the above-described embodiment, a cleaning blade 30 for removing toner remaining on the surface of the photosensitive drum 11 was exemplified. However, the use of the cleaning blade 30 according to the present disclosure is not limited to the above-described example. For example, a cleaning blade 30 (cleaning device 18) having a configuration similar to that of each of the above-described embodiments can also be used to clean the surfaces of other elements, such as the transfer roll 16 or a transfer belt. Elements that come into contact with the cleaning blade 30 are collectively referred to as "target objects." The "target object" can also be expressed as an object to be cleaned by the cleaning blade 30. The photosensitive drum 11 in the above-described embodiment is an example of an "target object." Another example of an "target object" is a transfer member, such as the transfer roll 16 or a transfer belt, that transfers toner adhering to the surface of the photosensitive drum 11 to the recording medium 200. The "target object" can also be expressed as a structure including a cylindrical outer surface that comes into contact with the cleaning blade 30.

[0040] B: Supplementary Notes From the above-described exemplary embodiments, the following configurations can be understood, for example.

[0041] A cleaning device according to one aspect (Aspect 1) of the present disclosure includes a plate-shaped cleaning blade including a tip portion that contacts an object, and a support member that supports the cleaning blade. The amount of displacement, which is the distance between the position of the tip portion when the object is not rotating and the position of the tip portion when the object is rotating, is 32 μm or less. The smaller the amount of displacement of the tip portion, the more likely wear of the tip portion is to be suppressed. Therefore, according to the aspect in which the amount of displacement of the tip portion when the object is rotating is 32 μm or less, wear of the tip portion can be effectively suppressed.

[0042] In a specific example (Aspect 2) of Aspect 1, the 100% modulus of the cleaning blade in an environment of 23° C. is 5.3 MPa or more and 13.6 MPa or less. In the above-mentioned aspect, since the 100% modulus of the cleaning blade in an environment of 23° C. is 5.3 MPa or more, wear at the tip portion can be suppressed compared to, for example, an embodiment in which the 100% modulus is less than 5.3 MPa. Furthermore, since the 100% modulus of the cleaning blade in an environment of 23° C. is 13.6 or less, wear of the object caused by contact with the cleaning blade can be effectively suppressed compared to, for example, an embodiment in which the 100% modulus exceeds 13.6.

[0043] In a specific example (Aspect 3) of Aspect 1 or Aspect 2, the tip angle is 92° or more and 110° or less. In the above aspect, because the tip angle is 92° or more, wear at the tip can be suppressed compared to an aspect in which the tip angle is excessively small. Furthermore, because the tip angle is 110° or less, a cleaning blade with highly accurate flat side surfaces can be easily manufactured by cutting the elastic substrate compared to an aspect in which the tip angle is excessively large.

[0044] In a specific example (Aspect 4) of Aspect 3, the tip angle is 95° or more and 105° or less. In this aspect, because the tip angle is 95° or more, the effect of suppressing wear at the tip is significant compared to aspects in which the tip angle is less than 95°. Furthermore, because the tip angle is 105° or less, a cleaning blade with highly accurate flat side surfaces can be easily manufactured by the step of cutting the elastic substrate, compared to aspects in which the tip angle exceeds 105°.

[0045] In a specific example (Aspect 5) of any one of Aspects 1 to 4, the object is a photosensitive drum. According to the above aspect, wear of the tip of the cleaning blade is suppressed, so that toner remaining on the surface of the photosensitive drum can be removed for a long period of time.

[0046] In a specific example (Aspect 6) of any of Aspects 1 to 5, the target object is a transfer member that transfers toner adhering to the surface of the photosensitive drum to a recording medium. According to the above aspect, wear at the tip of the cleaning blade is suppressed, so that toner remaining on the surface of the transfer member can be removed over a long period of time.

[0047] 100...image forming apparatus, 200...recording medium, 11...photosensitive drum, 12...charging roll, 13...exposure device, 14...supply roll, 15...developing roll, 16...transfer roll, 17...fixing roll, 18...cleaning device, 20...support member, 30...cleaning blade, 31...first surface, 32...second surface, 33...extension portion, 36...tip portion.

Claims

1. A cleaning device comprising: a plate-shaped cleaning blade including a tip that contacts an object; and a support member that supports said cleaning blade, wherein the displacement, which is the distance between the position of said tip when the object is not rotating and the position of said tip when the object is rotating, is 32 μm or less.

2. The cleaning device according to claim 1, wherein the 100% modulus of the cleaning blade in a 23°C environment is 5.3 MPa or more and 13.6 MPa or less.

3. A cleaning device according to claim 1 or claim 2, wherein the angle of the tip is between 92° and 110°.

4. The cleaning device according to claim 3, wherein the angle of the tip is between 95° and 105°.

5. The cleaning device according to claim 1, wherein the object is a photosensitive drum.

6. The cleaning device according to claim 1, wherein the object is a transfer member that transfers toner adhering to the surface of the photosensitive drum onto a recording medium.

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