Cleaning device

Abstract

A cleaning device includes a plate-shaped cleaning blade having a front end portion configured to come into contact with a target object, and a support member that supports the cleaning blade, wherein a displacement amount of the front end portion is 32 μm or less, the displacement amount being a distance between a position of the front end portion in a state where the target object is stopped from rotating and a position of the front end portion in a state where the target object is rotating.

Description

Technical Field

[0001] This invention relates to a cleaning apparatus for electrophotographic image formation. Background Technology

[0002] In an electrophotographic image forming apparatus, a cleaning device is provided to remove toner residues on the surface of a photosensitive drum. Patent Document 1 discloses a structure in which a flat, elastic member (cleaning scraper) is fixed to a support member.

[0003] Existing technical documents Patent documents Patent Document 1: WO2022 / 138076 Summary of the Invention

[0004] The problem the invention aims to solve The photosensitive drum rotates with the front end of the cleaning blade in contact with it; therefore, as the photosensitive drum rotates, the front end wears down over time. It should be noted that although the above description focuses on the photosensitive drum for convenience, similar problems can occur in any structure where the component rotates while in contact with the cleaning blade. In view of the above, one aspect of this disclosure is to reduce wear on the front end of the cleaning blade.

[0005] Problem-solving methods To address the aforementioned problems, a cleaning apparatus according to one aspect of this disclosure includes a plate-shaped cleaning scraper and a support member. The cleaning scraper has a front end configured to contact a target object, and the support member supports the cleaning scraper. The displacement of the front end is less than 32 μm, and the displacement is the distance between the position of the front end when the target object is not rotating and the position of the front end when the target object is rotating. Attached Figure Description

[0006] Figure 1 This is a diagram illustrating the structure of an image forming apparatus according to an embodiment.

[0007] Figure 2 This is a cross-sectional view of the cleaning device.

[0008] Figure 3 This is an explanatory diagram regarding the angle of the front end of the cleaning scraper.

[0009] Figure 4 The material composition of each sample is shown.

[0010] Figure 5 This is an explanatory diagram showing a method for measuring the displacement of the front end.

[0011] Figure 6 It is a graph showing the results of measuring the displacement of the front end.

[0012] Figure 7 This is an explanatory diagram showing a method for measuring the wear of the front end.

[0013] Figure 8 The results of measuring 100% modulus, displacement, and wear for each sample are shown.

[0014] Figure 9 It is a scatter plot showing the relationship between displacement and wear in each sample. Detailed Implementation

[0015] Embodiments according to the present disclosure will now be described with reference to the accompanying drawings. It should be noted that the dimensions and proportions of the elements in the various drawings may differ from those of the actual product. Furthermore, the embodiments described below are exemplary embodiments contemplated for the implementation of this disclosure. Therefore, the scope of this disclosure is not limited to the embodiments described below.

[0016] A: Example Figure 1 This is a diagram illustrating the construction of an image forming apparatus 100 according to an embodiment of the present disclosure. The image forming apparatus 100 is, for example, an electrophotographic printer (e.g., a multifunction peripheral device) for forming images on a sheet recording medium 200 such as printing paper, and includes a photosensitive drum 11, a charging roller 12, an exposure device 13, a supply roller 14, a developing roller 15, a transfer roller 16, a fixing roller 17, and a cleaning device 18.

[0017] The photosensitive drum 11 is a cylindrical photosensitive body with an outer peripheral surface formed of photosensitive material. The charging roller 12 is a conductive roller configured to uniformly charge the surface of the photosensitive drum 11. The exposure device 13 forms an electrostatic latent image by exposing the photosensitive drum 11. The supply roller 14 supplies toner in a charged state to the surface of the developing roller 15. The developing roller 15 causes the toner to adhere to the electrostatic latent image on the surface of the photosensitive drum 11. The transfer roller 16 transfers the toner adhered to the surface of the photosensitive drum 11 to the recording medium 200. The fixing roller 17 fixes the toner transferred to the surface of the recording medium 200. The cleaning device 18 removes the toner remaining on the surface of the photosensitive drum 11.

[0018] Figure 2 This is a cross-sectional view of the cleaning device 18. The cleaning device 18 is located in the direction of the rotation axis of the photosensitive drum 11 (i.e., perpendicular to the axis of rotation). Figure 2 Structures extending along a plane. For example... Figure 1 and Figure 2 As shown, the cleaning device 18 includes a support member 20 and a cleaning scraper 30.

[0019] The support member 20 is a plate-like structure (holder, bracket) that supports the cleaning scraper 30. The material of the support member 20 is appropriately selected; for example, a high-rigidity metal material such as galvanized steel sheet is used as the main material of the support member 20.

[0020] The cleaning squeegee 30 is a plate-shaped elastic member including a front end 36. Specifically, the cleaning squeegee 30 is a plate-shaped member having a predetermined thickness (e.g., about 2 mm) and being formed into a rectangular shape that is elongated in the direction of the rotation axis of the photosensitive drum 11. The cleaning squeegee 30 is fixed to the support member 20, for example, by adhesive.

[0021] The front end portion 36 is an edge configured to contact 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 facing the photosensitive drum 11. The second surface 32 is the side surface that forms the tip surface of the cleaning blade 30. The front end portion 36 is the portion where the first surface 31 and the second surface 32 intersect. The angle α of the front end portion 36 is the angle between the first surface 31 and the second surface 32. In the following description, consideration will be given to the angle α when the front end portion 36 is not in contact with the photosensitive drum 11.

[0022] Figure 3 This is an explanatory diagram of angle α. Angle α is the angle between line segment L1 along the first surface 31 and line segment L2 along the second surface 32. Line segment L1 and line segment L2 are, for example, line segments each with a length of 100 μm. Line segment L1 is a virtual line segment that approximates the first surface 31 in the cross-section of the cleaning scraper 30, and line segment L2 is a virtual line segment that approximates the second surface 32 in the same cross-section.

[0023] When the photosensitive drum 11 rotates with its front end 36 in contact (i.e., sliding) with the surface of the photosensitive drum 11, the front end 36 will wear over time. In the cleaning device 18, it is important to reduce the amount of wear on the front end 36. From the viewpoint of reducing wear on the front end 36, the inventors measured various characteristics of multiple samples (executives and comparative examples) of the cleaning scraper 30. Figure 4 The material composition of each sample is shown. Figure 4 The figures show the weight parts of each constituent material when the weight of the substrate (specifically, polyol) of the cleaning scraper 30 is set to 100.

[0024] Each sample was made of polyurethane. As the polyol for the polyurethane, "Kuraray Polyol O-2010" (molecular weight: 2000) manufactured by Kuraray Corporation was used in material composition A, and "POLYLITE CT-4117" (molecular weight: 2000) manufactured by DIC Corporation was used in material compositions B to I. Furthermore, the isocyanate of the polyurethane was 4,4′-diphenylmethane diisocyanate (MDI). Specifically, "MILLIONATE MT" manufactured by Tosoh Corporation was used as this isocyanate.

[0025] In material compositions A to C and I, trimethylolethane (TME) manufactured by Hiroyo Chemical Industries, Ltd. was used as a crosslinking agent, and 1,3-propanediol (1,3PD) manufactured by Mitsubishi Chemical Corporation was used as a chain extender. Furthermore, in material compositions D to H, trimethylolpropane (TMP) manufactured by Persto Japan Ltd. was used as a crosslinking agent, and 1,4-butanediol (1,4BD) manufactured by Mitsubishi Chemical Corporation was used as a chain extender.

[0026] For multiple samples with different combinations of the above material composition and angle α of the front end 36, the following were measured: (1) 100% modulus at 23 degrees Celsius, (2) displacement of the front end 36, and (3) wear of the front end 36. It should be noted that the total length of each sample is 50 mm and the thickness is 2 mm. Furthermore, the free length of each sample is 9 mm. Figure 2 As shown, the free length is the length of the portion of the cleaning scraper 30 that protrudes from the end 21 of the support member 20 (hereinafter referred to as "protrusion 33"). In other words, the protrusion 33 is the portion configured to elastically deform in relation to the rotation of the photosensitive drum 11.

[0027] 100% modulus is a hardness indicator for the cleaning scraper 30. Specifically, 100% modulus is the tensile stress (MPa) required to impart 100% elongation to the cleaning scraper 30. Specifically, the 100% modulus of each sample was measured at 23 degrees Celsius according to Japanese Industrial Standard (JIS) K 6251 (2017) "Vulcanized rubber or thermoplastic rubber—Determination of tensile stress-strain properties".

[0028] The displacement is the distance (movement) by which the front end 36 is displaced when the photosensitive drum 11 rotates. Specifically, as shown... Figure 5 As shown, the displacement of the front end 36 in each sample is measured using a pseudo-photoreceptor 50 and an imaging device 55.

[0029] The pseudo-photoreceptor 50 is a cylindrical structure that simulates the photosensitive drum 11. Specifically, the pseudo-photoreceptor 50 is manufactured by forming a polycarbonate layer 52 on the outer peripheral surface of a cylindrical glass component 51 with a diameter of 40 mm. A lubricant is coated on the outer peripheral surface of the pseudo-photoreceptor 50. Specifically, "HYLAR301F" (polyvinylidene fluoride: PVDF) manufactured by Solvay Corporation of Japan is used as the lubricant. The amount of lubricant applied is 0.1 mg.

[0030] The contact angle between the cleaning blade 30 and the surface of the pseudo-photoreceptor 50 is 20°. The cleaning blade 30 is installed such that the load applied from the cleaning blade 30 to the surface of the pseudo-photoreceptor 50 is 0.18 N / cm. The ambient temperature for measurement is 23 degrees Celsius, and the humidity (relative humidity) is 55%.

[0031] In the aforementioned environment, the spurious photoreceptor 50 is rotated with its front end 36 in contact with the outer peripheral surface of the spurious photoreceptor 50, and the front end 36 is photographed from the inside of the spurious photoreceptor 50 by the imaging device 55, thereby measuring the displacement of the front end 36. The rotational speed of the spurious photoreceptor 50 is 460 mm / sec. The imaging device 55 is a charge-coupled device (CCD) camera mounted inside the spurious photoreceptor 50. Specifically, dot-shaped marks are added to the front end 36, and the movement of these marks on the front end 36 is analyzed based on the analysis of the image captured by the imaging device 55.

[0032] Figure 6 This is a graph showing the time-varying displacement of the front end 36 as the pseudo-photosensor 50 rotates. Figure 6 At time T0, the pseudo-photoreceptor 50 begins to rotate. Figure 6 It will be understood that the displacement of the front end portion 36 reaches its maximum value immediately after the pseudo-photoreceptor 50 begins to rotate, and thereafter fluctuates periodically with a small amplitude. The distance between the position of the front end portion 36 when the pseudo-photoreceptor 50 is stopped rotating and the position of the front end portion 36 when the pseudo-photoreceptor 50 is rotating (specifically, the state where the displacement becomes maximum immediately after the start of rotation) is measured as the displacement of the front end portion 36. Figure 6 It will be understood that the displacement of the front end 36 becomes maximum immediately after the pseudo-photoreceptor 50 begins to rotate; therefore, the measurement result can also be expressed as the maximum value of the displacement of the front end 36.

[0033] Wear amount is an indicator of the degree of wear on the front end 36 caused by friction with the rotating photosensitive drum 11. For example... Figure 7 As shown, the wear amount of each sample was measured using a pseudo-photoreceptor 60.

[0034] The pseudo-photoreceptor 60 is a cylindrical structure that simulates the photosensitive drum 11. Specifically, the pseudo-photoreceptor 60 is manufactured by covering the surface of a rotatable cylinder 61 with a polishing film 62. The polishing film 62 is an abrasive material used to promote wear on the tip 36. Specifically, "Abrasive Film #15000 A3-0.3SHT" manufactured by 3M Japan Co., Ltd. is used as the polishing film 62. The surface roughness of the polishing film 62 is 0.3 μm.

[0035] The contact angle between the cleaning blade 30 and the surface of the pseudo-photoreceptor 60 is 20°. The cleaning blade 30 is installed such that the load applied from the cleaning blade 30 to the surface of the pseudo-photoreceptor 60 is 0.18 N / cm. The ambient temperature for measurement is 23 degrees Celsius, and the humidity (relative humidity) is 55%.

[0036] In the aforementioned environment, the pseudo-photoreceptor 60 is rotated with the front end 36 of the sample in contact with the outer peripheral surface of the pseudo-photoreceptor 60, and the amount of wear is measured during a phase in which the sample slides a predetermined sliding distance relative to the pseudo-photoreceptor 60. Specifically, after the test, the front end 36 is photographed by an imaging device (not shown), and the area of ​​the worn portion is calculated as the amount of wear. It should be noted that the sliding distance corresponds to the distance equivalent to five longitudinally arranged A4-sized printing papers, and the rotational speed of the pseudo-photoreceptor 50 is 460 mm / sec.

[0037] Figure 8 The results of measuring 100% modulus, displacement, and wear for each sample (Comparative Examples 1 to 8 and Examples 1 to 13) with different combinations of material composition and angle α are shown. It should be noted that the 100% modulus value is the same for samples with a common material composition. Furthermore, Figure 9 It is a scatter plot showing the relationship between the displacement and wear of each sample.

[0038] In Comparative Examples 1 to 8, the angle α of the front end 36 is 90°. On the other hand, in Examples 1 to 13, the angle α is an obtuse angle (90° < α < 180°). Figure 9 As will be understood from Figure 10, the displacement amounts in Examples 1 to 13 are reduced compared to Comparative Examples 1 to 8. Specifically, in Comparative Examples 1 to 8, the displacement amounts exceeded 32 μm, while in Examples 1 to 13, the displacement amounts were reduced to below 32 μm. It should be noted that... Figure 2 The cleaning scraper 30 is shown to have a parallelogram cross-sectional shape; however, the planar shape of the cleaning scraper 30 is appropriately chosen.

[0039] from Figure 9It will be understood that there is a trend that the smaller the displacement of the front end portion 36, the lower the wear of the front end portion 36. In Examples 1 to 13, where the displacement is reduced to below 32 μm, the wear of the front end portion 36 is reduced to 46 μm. 2 Therefore, based on the above measurement results, from the viewpoint of reducing wear on the front end 36, it is preferable that the displacement of the front end 36 during the rotation of the photosensitive drum 11 is 32 μm or less. More preferably, the displacement of the front end 36 is 28 μm or less.

[0040] In addition, from Figure 8 and Figure 9 It will be understood that in embodiments 1 to 13, where the angle α of the front end portion 36 is 92° or more, the displacement is reduced to 32 μm or less. Therefore, a structure in which the angle α of the front end portion 36 is 92° or more is preferred. More preferably, the angle α of the front end portion 36 is set to 95° or more.

[0041] As described above, from the viewpoint of reducing displacement, a structure with a larger angle α at the front end 36 is preferred. However, in a structure with an excessively large angle α, the second surface 32 has a large area; therefore, during the manufacturing process of the cleaning scraper 30 by cutting a large elastic substrate, it is difficult to maintain the second surface 32, which serves as the cutting surface, as a highly precise flat surface. From the viewpoint of maintaining the second surface 32 as a highly precise flat surface, a structure with an angle α of 110° or less at the front end 36 is preferred. More preferably, the angle α of the front end 36 is set to 105° or less.

[0042] As described above, in the preferred configuration of this disclosure, the angle α of the front end portion 36 is 92° or more and 110° or less. In a more preferred configuration, the angle α of the front end portion 36 is 95° or more and 105° or less. According to the above configuration, both wear on the front end portion 36 can be reduced and the second surface 32 can be maintained as a highly precise flat surface.

[0043] from Figure 8 and Figure 9 It will be understood that in Examples 1 to 13, where the 100% modulus is 5.3 MPa or higher at 23 degrees Celsius, the displacement is reduced to 32 μm or less. Therefore, it is preferable that the cleaning scraper 30 has a 100% modulus of 5.3 MPa or higher at 23 degrees Celsius.

[0044] As described above, from the viewpoint of reducing displacement, a structure with a larger 100% modulus of the front end portion 36 is preferred at an environment of 23 degrees Celsius. However, in a structure with an excessively large 100% modulus, the front end portion 36 becomes very rigid; therefore, the surface of the photosensitive drum 11 may wear due to the sliding of the front end portion 36. From the viewpoint of reducing wear on the surface of the photosensitive drum 11, a structure with a 100% modulus of the front end portion 36 of 13.6 MPa or less is preferred at an environment of 23 degrees Celsius.

[0045] As described above, in a preferred aspect of this disclosure, the cleaning blade 30 has a 100% modulus of 5.3 MPa or more and 13.6 MPa or less at an environment of 23 degrees Celsius. According to this aspect, wear on both the front end 36 and the photosensitive drum 11 can be reduced.

[0046] As described above, according to this embodiment, during the rotation of the photosensitive drum, the displacement of the front end portion 36 of the cleaning scraper 30 is less than 32 μm; therefore, wear on the front end portion 36 can be effectively reduced.

[0047] It should be noted that in the above embodiments, an example of a cleaning blade 30 for removing toner residue on the surface of the photosensitive drum 11 is described; however, the application of the cleaning blade 30 according to this disclosure is not limited to the above example. For example, a cleaning blade 30 (cleaning device 18) having a similar structure to the above aspects can be applied to clean the surface of another element (such as the transfer roller 16 or transfer belt). The element that the cleaning blade 30 contacts is collectively referred to as a "target object". A "target object" can be represented as an object to be cleaned by the cleaning blade 30. The photosensitive drum 11 in the above embodiments is an example of a "target object". In addition, a transfer member (such as the transfer roller 16 or transfer belt) configured to transfer toner adhering to the surface of the photosensitive drum 11 onto the recording medium 200 is also an example of a "target object". A "target object" can be represented as a structure including a cylindrical outer peripheral surface that contacts the cleaning blade 30.

[0048] B: Supplementary Notes For example, the following construction can be derived from the foregoing embodiments.

[0049] A cleaning apparatus according to one aspect of this disclosure (Aspect 1) includes a plate-shaped cleaning scraper and a support member. The cleaning scraper has a front end configured to contact a target object, and the support member supports the cleaning scraper. The displacement of the front end is 32 μm or less, and the displacement is the distance between the position of the front end when the target object is stationary and the position of the front end when the target object is rotating. There is a tendency that the smaller the displacement of the front end, the greater the reduction in wear on the front end. Therefore, according to the aspect where the displacement of the front end is 32 μm or less during target object rotation, wear on the front end can be effectively reduced.

[0050] In a specific example of Aspect 1 (Aspect 2), the cleaning blade has a 100% modulus of 5.3 MPa or more and 13.6 MPa or less at 23 degrees Celsius. In the above aspect, the cleaning blade has a 100% modulus of 5.3 MPa or more at 23 degrees Celsius; therefore, compared to a structure with a 100% modulus less than 5.3 MPa, wear on the front end can be reduced. Furthermore, the cleaning blade has a 100% modulus of 13.6 MPa or less at 23 degrees Celsius; therefore, compared to a structure with a 100% modulus greater than 13.6 MPa, wear on the target object caused by contact with the cleaning blade can be effectively reduced.

[0051] In a specific example (Aspect 3) of aspect 1 or aspect 2, the angle of the front end is 92° or more and 110° or less. In the above aspect, the angle of the front end is 92° or more; therefore, compared to a structure with an excessively small angle at the front end, wear on the front end can be reduced. Furthermore, the angle of the front end is 110° or less; therefore, compared to a structure with an excessively large angle at the front end, a cleaning scraper having a side surface with high precision flatness can be easily manufactured using a process of cutting an elastic substrate.

[0052] In a specific example of aspect 3 (aspect 4), the angle of the front end is 95° or more and 105° or less. In the aforementioned aspect, the angle of the front end is 95° or more; therefore, compared to a construction where, for example, the angle of the front end is less than 95°, the effect of reducing wear on the front end is significant. Furthermore, the angle of the front end is 105° or less; therefore, compared to a construction where, for example, the angle of the front end exceeds 105°, a cleaning scraper with a side surface that is a high-precision flat surface can be easily manufactured by the process of cutting the elastic substrate.

[0053] In a specific example of any of aspects 1 to 4 (aspect 5), the target object is a photosensitive drum. According to the above aspects, wear on the front end of the cleaning blade is reduced; therefore, toner residue on the surface of the photosensitive drum can be removed over a long period of time.

[0054] In a specific example of any of aspects 1 to 5 (aspect 6), the target object is a transfer member configured to transfer toner adhering to the surface of a photosensitive drum onto a recording medium. According to the above aspects, wear on the front end of the cleaning blade is reduced; therefore, toner residue on the surface of the transfer member can be removed over a long period.

[0055] Explanation of reference numerals in the attached figures 100…Image forming apparatus, 200…Recording medium, 11…Photosensitive drum, 12…Charging roller, 13…Exposure apparatus, 14…Feed roller, 15…Developing roller, 16…Transfer roller, 17…Fixing roller, 18…Cleaning apparatus, 20…Support member, 30…Cleaning blade, 31…First surface, 32…Second surface, 33…Protrusion, 36…Front end.

Claims

1. A cleaning device comprising: A plate-shaped cleaning scraper having a front end configured to contact the target object; and Supporting member that supports the cleaning scraper, Wherein, the displacement of the front end is less than 32μm, and the displacement is the distance between the position of the front end when the target object stops rotating and the position of the front end when the target object is rotating.

2. The cleaning device according to claim 1, wherein, The cleaning scraper has a 100% modulus of 5.3 MPa or more and 13.6 MPa or less at 23 degrees Celsius.

3. The cleaning apparatus according to claim 1 or 2, wherein, The angle of the front end is greater than 92° and less than 110°.

4. The cleaning device according to claim 3, wherein, The angle of the front end is greater than 95° and less than 105°.

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

6. The cleaning apparatus according to claim 1, wherein, The target object is a transfer component configured to transfer toner adhering to the surface of a photosensitive drum onto a recording medium.

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