Electrophotographic cleaning blade, processing cartridge, and electrophotographic image forming apparatus

Abstract

The present invention aims to provide a cleaning blade for electrophotography, which has excellent chipping resistance and can provide excellent cleaning performance. The cleaning blade is provided with an elastic member containing polyurethane and a support member for supporting the elastic member, and the surface of the member to be cleaned is cleaned by bringing a part of the elastic member into contact with the surface of the moving member to be cleaned. The average value of the elastic modulus of the elastic member obtained when measured by SPM is 15 - 470 MPa, and its coefficient of variation is 6.0% or less.

Description

Technical Field

[0001] The present invention relates to a cleaning blade for electrophotographic apparatuses, a process cartridge, and an electrophotographic image forming apparatus. Background Art

[0002] In electrophotographic apparatuses, a cleaning member is provided for removing toner remaining on the surface of an image carrier member (such as a photosensitive member) or an intermediate transfer member (hereinafter, the image carrier member and the intermediate transfer member are also referred to as members to be cleaned) after transferring a toner image from the image carrier member or the intermediate transfer member to a transfer member. One of these cleaning members is a cleaning blade.

[0003] PTL 1 discloses a cleaning blade made of a polyurethane member, the cleaning blade including a polyurethane material containing hard segments and soft segments, and wherein the proportion of the area occupied by hard segment aggregates having a diameter of 0.3 μm or more and 0.7 μm or less in a cross section is 2% or more and 10% or less. It is disclosed that by using such a cleaning blade, both chipping resistance and abrasion resistance can be obtained simultaneously.

[0004] According to research conducted by the present inventors, the cleaning blade of PTL 1 still has room for improvement in terms of chipping resistance. Specifically, for example, when the cleaning blade is used for a long time in a low temperature and low humidity environment (such as a temperature of 15°C and a relative humidity of 10%), chipping occurs.

[0005] Citation List

[0006] Patent Document

[0007] [PTL 1] Japanese Patent Application Laid-Open No. 2016-14740 Summary of the Invention

[0008] Problems to be Solved by the Invention

[0009] One aspect of the present invention aims to provide a cleaning blade for electrophotography having excellent chipping resistance and capable of stably exhibiting excellent cleaning performance. Further, another aspect of the present invention aims to provide a process cartridge that contributes to the stable formation of high-quality electrophotographic images. In addition, yet another aspect of the present invention aims to provide an electrophotographic image forming apparatus capable of stably forming high-quality electrophotographic images.

[0010] Solutions to the Problems

[0011] According to one aspect of the present invention, there is provided

[0012] An electrophotographic cleaning blade, which includes an elastic member containing polyurethane and a support member supporting the elastic member, and which cleans the surface of a moving member to be cleaned by bringing a part of the elastic member into contact with the surface of the member to be cleaned, wherein,

[0013] when the side of the cleaning blade that contacts the surface of the member to be cleaned is defined as the tip side of the cleaning blade,

[0014] the elastic member has at least a plate shape on the tip side, the plate shape having a main surface facing the member to be cleaned and a tip surface that forms a tip-side edge together with the main surface;

[0015] assuming that a first line segment is drawn parallel to the tip-side edge on the tip surface at a distance of 10 μm from the tip-side edge, wherein

[0016] the length of the first line segment is represented by L, and

[0017] points at 1 / 8L, 1 / 2L, and 7 / 8L from one end side on the first line segment are represented by P0, P1, and P2, respectively,

[0018] the average value of the elastic modulus of the elastic member measured by using SPM at each of 70 points spaced 1 μm apart on the first line segment centered on each of P0, P1, and P2 on the first line segment is 15 MPa or more and 470 MPa or less;

[0019] the coefficient of variation of the elastic modulus is 6.0% or less; and

[0020] the absolute value of the difference between the Martens hardness HM1 of the elastic member measured at the position of P1 and the Martens hardness HM2 of the elastic member measured at a position 500 μm from the tip-side edge on the bisector of the angle formed by the main surface and the tip surface when assuming that a bisector of the angle formed by the main surface and the tip surface is drawn on a cross section of the elastic member that includes P1 and is orthogonal to the tip surface and the tip-side edge is 0.10 N / mm 2 or less.

[0021] According to another aspect of the present invention, there is provided

[0022] An electrophotographic cleaning blade, which includes an elastic member containing polyurethane and a support member supporting the elastic member, and which cleans the surface of a moving member to be cleaned by bringing a part of the elastic member into contact with the surface of the member to be cleaned, wherein

[0023] when the side of the cleaning blade that contacts the surface of the member to be cleaned is defined as the tip side of the cleaning blade,

[0024] The elastic member has at least a plate shape on the top end side, and the plate shape has a main surface facing the member to be cleaned and a top surface that forms a top end side edge together with the main surface;

[0025] Assume that a second line segment is drawn on the top surface parallel to the top end side edge at a distance of 10 μm from the top end side edge, and when

[0026] The length of the second line segment is represented by L, and

[0027] When points at 1 / 8L, 1 / 2L, and 7 / 8L from one end side of the second line segment are represented by P0, P1, and P2 respectively,

[0028] In each of three square observation regions on the top surface that have P0, P1, and P2 as their respective centers of gravity, have a side length of 1 μm, and have one side parallel to the second line segment, the proportion [(S2 / S1)×100)] of the number S2 of hard segment chains with a circular equivalent diameter of 40 nm or less in the total number S1 of hard segment chains is 92% or more, and

[0029] The S1 is 300 or more and 1500 or less.

[0030] According to another aspect of the present invention, there is provided

[0031] A cleaning blade for electrophotography, which includes an elastic member containing polyurethane and a support member that supports the elastic member, and which cleans the surface of the member to be cleaned by bringing a part of the elastic member into contact with the surface of the moving member to be cleaned, wherein

[0032] When the side of the cleaning blade that contacts the surface of the member to be cleaned is defined as the top end side of the cleaning blade,

[0033] The elastic member has at least a plate shape on the top end side, and the plate shape has a main surface facing the member to be cleaned and a top surface that forms a top end side edge together with the main surface;

[0034] Assume that a third line segment is drawn on the top surface parallel to the top end side edge at a distance of 0.5 mm from the top end side edge, wherein

[0035] The length of the third line segment is represented by L', and

[0036] Points at 1 / 8L', 1 / 2L', and 7 / 8L' from one end side of the third line segment are represented by P0', P1', and P2' respectively, and

[0037] When the samples respectively sampled at P0', P1', and P2' are heated to 1000 °C at a temperature increase rate of 10 °C / second by using a direct injection type mass spectrometer in which the samples are heated and vaporized in an ionization chamber and the sample molecules are ionized,

[0038] wherein the detected amount of all ions is represented by M1,

[0039] the integrated intensity of the peak of the extracted ion thermogram corresponding to the m / z value in the range of 380.5 to 381.5 derived from polymeric MDI is represented by M2,

[0040] the integrated intensity of the peak of the extracted ion thermogram corresponding to the m / z value in the range of 249.5 to 250.5 derived from 4,4'-MDI is represented by M3, and

[0041] the integrated intensity of the peak of the extracted ion thermogram corresponding to the m / z value in the range of 749.5 to 750.5 in the isocyanurate form of 4,4'-MDI is represented by M4,

[0042] M2 / M1 is 0.001 to 0.015,

[0043] M3 / M1 is 0.04 to 0.10, and

[0044] M4 / M1 is 0.001 or less, and

[0045] the concentration of the trifunctional alcohol in the polyurethane is 0.22 to 0.39 mmol / g.

[0046] According to another aspect of the present invention, there is provided

[0047] a cleaning blade for electrophotography, which includes an elastic member containing polyurethane and a support member for supporting the elastic member, and which cleans the surface of the member to be cleaned by bringing a part of the elastic member into contact with the surface of the moving member to be cleaned, wherein

[0048] when defining the side of the cleaning blade that contacts the surface of the member to be cleaned as the tip side of the cleaning blade,

[0049] the elastic member has at least a plate shape on the tip side, and the plate shape has a main surface facing the member to be cleaned and a tip surface that forms a tip side edge together with the main surface;

[0050] assuming that a fourth line segment is drawn on the tip surface parallel to the tip side edge at a distance of 0.5 mm from the tip side edge, wherein

[0051] the length of the fourth line segment is represented by L', and

[0052] The points at 1 / 8L', 1 / 2L', and 7 / 8L' from one end side on the fourth line segment are represented by P0', P1', and P2', respectively.

[0053] In the DSC chart obtained by differential scanning calorimetry through the samples respectively sampled at the P0', the P1', and the P2',

[0054] the peak temperature of the only endothermic peak is 200 °C or higher,

[0055] the melting start temperature of the endothermic peak is 175 °C or higher, and

[0056] the difference between the melting start temperature and the peak temperature is 15 °C or higher.

[0057] Furthermore, according to another aspect of the present invention, a processing cartridge having the electrophotographic cleaning blade is provided. In addition, according to another aspect of the present invention, an electrophotographic image forming apparatus having the electrophotographic cleaning blade is provided.

[0058] Effects of the Invention

[0059] According to one aspect of the present invention, a cleaning blade having excellent shatter resistance and capable of stably exhibiting excellent cleaning performance can be obtained. Further, according to another aspect of the present invention, a processing cartridge that contributes to forming a high-quality electrophotographic image can be obtained. In addition, according to still another aspect of the present invention, an electrophotographic image forming apparatus capable of stably forming a high-quality electrophotographic image can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 is a schematic perspective view of an electrophotographic cleaning blade according to one aspect of the present invention.

[0061] Figure 2 shows a state where the edge of the cleaning blade contacts the member to be cleaned when the processing cartridge is stationary.

[0062] Figure 3 shows a line segment parallel to the top end side edge and at a distance of 10 μm from the top end side edge on the top end surface, which is used to measure the elastic modulus obtained by SPM.

[0063] Figure 4 shows the cut position of the sample for SPM measurement.

[0064] Figure 5 shows the positions for SPM measurement and for measuring the Martens hardness HM1.

[0065] ​​​​​​Figure 6 Shows the position for measuring the Martens hardness HM2.

[0066] Figure 7 Shows the position for measuring the size and number of hard segments.

[0067] Figure 8 Shows the position where measurement is carried out by the direct injection method (DI method).

[0068] Figure 9 Shows the measurement method for edge chipping.

[0069] Figure 10 Is a DSC graph related to the elastic member of the electrophotographic cleaning blade according to an aspect of the present invention and obtained by differential scanning calorimetry measurement.

[0070] Figure 11 Figure 11 (a) Shows the binary image obtained from the elastic member according to Example 1, and Figure 11 (b) Is the binary image obtained from the elastic member according to Comparative Example 1. Detailed Description of the Invention

[0071] In the present invention, unless otherwise specified, the description of "XX or more and YY or less" or "XX to YY" representing a numerical range means a numerical range including the lower limit and the upper limit as endpoints.

[0072] When numerically describing ranges stepwise, the upper and lower limits of each numerical range can be arbitrarily combined.

[0073] Examples of the member to be cleaned to which the electrophotographic cleaning blade (hereinafter, also simply referred to as "cleaning blade") according to an aspect of the present invention is applied include image bearing members such as photosensitive members, and annular belts such as intermediate transfer belts. Hereinafter, embodiments of the cleaning blade according to an aspect of the present invention will be described in detail by taking the image bearing member as an example of the member to be cleaned, but the present invention is not limited thereto.

[0074] <Structure of the cleaning blade>

[0075] Figure 1 Is a schematic perspective view of a cleaning blade 1 according to an aspect of the present invention. The cleaning blade 1 includes an elastic member 2 and a support member 3 that supports the elastic member 2.

[0076] Figure 2 ​​​​​​An example of a state of a cross section in which a cleaning blade according to an aspect of the present invention is in contact with a member to be cleaned is schematically shown. A side of the cleaning blade that contacts the surface of the member to be cleaned is defined as the top side of the cleaning blade. The elastic member 2 has a plate shape having a main surface 4 facing the member to be cleaned 6 and a top surface 5 that forms a top side edge together with the main surface 4. R represents the rotation direction of the member to be cleaned. A part of the elastic member is brought into contact with the surface of the moving member to be cleaned to clean the surface of the member to be cleaned.

[0077] The present inventors have found that, for example, a cleaning blade in the following form can exhibit excellent fracture resistance and excellent cleaning performance.

[0078] Assume that a first line segment is drawn parallel to the top side edge on the top surface of the elastic member including polyurethane at a distance of 10 μm from the top side edge.

[0079] The length of the first line segment is represented by L, and points at 1 / 8L, 1 / 2L, and 7 / 8L from one end side on the first line segment are represented by P0, P1, and P2, respectively (see Figure 3 , 4 and 5). The average value of the elastic modulus of the elastic member measured by SPM at each of 70 points spaced 1 μm apart on the first line segment centered on each of P0, P1, and P2 on the first line segment is 15 MPa or more and 470 MPa or less.

[0080] When the average value of the elastic modulus is 15 MPa or more, the contact pressure required for cleaning can be obtained, and when the average value of the elastic modulus is 470 MPa or less, the elastic member does not become too hard and has good followability with respect to the image bearing member, thereby suppressing the occurrence of poor cleaning.

[0081] When the number of durable printed products increases, an image bearing member such as a photosensitive member rubs against a contact member in a state where there is toner including fine particles on it, so that the surface is scratched and striped irregularities appear in the circumferential direction. Therefore, when the followability is poor, poor cleaning is likely to occur, but when the average elastic modulus is 470 MPa or less, the elastic member will follow the image bearing member even in a state where the surface of the image bearing member such as a photosensitive member has striped irregularities. Therefore, the occurrence of poor cleaning can be suppressed.

[0082] The average value of the elastic modulus is preferably 15 MPa or more and 60 MPa or less.

[0083] Furthermore, the coefficient of variation of the elastic modulus of the elastic member is 6.0% or less. In addition, the coefficient of variation is preferably 3.4% or less.

[0084] The coefficient of variation is calculated by the following formula (1).

[0085] Formula (1): Coefficient of variation (%) = Standard deviation / Average value of elastic modulus × 100

[0086] Polyurethane (specifically, polyurethane elastomer) is composed of hard segments and soft segments, and it is known that polyurethane (polyurethane elastomer) with changed mechanical properties can be obtained by changing the amount of hard segments having a reinforcing effect. However, when the aggregation of hard segments is promoted, the hard segments become larger, and as a result, the contact area with the soft segments increases. Therefore, when polyurethane is used under a stress state such as at the edge of a cleaning blade, the hard segments are likely to peel off from the soft segment part, and this peeling causes edge chipping. In order to cope with the reduction in size and spheroidization of toner particles promoted due to the demand for high image quality, it is preferable to suppress edge chipping to less than 3 μm, and more preferably to less than 1 μm.

[0087] As the aggregation of hard segments proceeds, the separation of hard segments and soft segments occurs simultaneously. When the elastic modulus of the cleaning blade in this state is measured at 70 points at an interval of 1 μm using SPM described below, even if the average value of the elastic modulus falls within the above range, the coefficient of variation of the elastic modulus becomes larger. That is, the presence of hard segments with aggregation leading to edge chipping can be indicated by a coefficient of variation greater than 6.0%.

[0088] Meanwhile, in the cleaning blade of the present invention, the aggregation of hard segments is suppressed, the hard segments are finely dispersed, and the dispersion is uniform and homogeneous. Therefore, when the elastic modulus is measured using SPM described below, the variation between the measured values is small, and the coefficient of variation of the elastic modulus is small.

[0089] Therefore, even when the average value of the elastic modulus at a specific position on the line segment is 15 MPa or more and 470 MPa or less, the coefficient of variation of the elastic modulus can be made 6.0% or less. As described above, since the hard segments of the entire elastic member are finely dispersed and the dispersion is uniform and homogeneous, edge chipping due to the peeling of hard segments is less likely to occur. Further, in a low-temperature environment, due to the temperature characteristics of the polyurethane elastomer, the viscosity becomes high, and the contact pressure tends to be insufficient. Therefore, even if there is a small degree of edge chipping, cleaning is likely to be poor. Since the cleaning blade of the present invention can suppress edge chipping, the occurrence of poor cleaning can be suppressed even in a low-temperature environment.

[0090] When the amount of hard segments decreases, due to the increase in the soft segment part, the coefficient of variation can be 6.0% or less, but the average value of the elastic modulus becomes less than 15 MPa, insufficient contact pressure is applied, and streak-like image defects appear due to toner slippage.

[0091] By introducing a structure with low regularity or low crystallinity into the hard segment, aggregation of the hard segment can be suppressed. Further, in the case where the crystallinity of the soft segment also becomes high, the soft segment tends to aggregate, and as a result, the hard segment is less likely to be dispersed. Therefore, by introducing a structure with low crystallinity into the soft segment, aggregation of the hard segment can be suppressed.

[0092] Further, it is assumed that a line segment at a distance of 10 μm from the edge is drawn parallel to the edge on the top surface of the elastic member, the length of the line segment is represented by L, and the Martens hardness at the point P1 at 1 / 2L from one end side of the line segment is represented by HM1.

[0093] Further, it is assumed that when a bisector of the angle formed by the main surface and the top surface is drawn on a cross section including P1 and orthogonal to the top surface and the top side edge, the Martens hardness of the elastic member measured at a position 500 μm from the top side edge on the drawn bisector is represented by HM2 (see Figure 6 ). In the elastic member of the present invention, the absolute value of the difference between the Martens hardness HM1 and the Martens hardness HM2 is 0.10 N / mm 2 The following. Further, the absolute value of the difference between the Martens hardness HM1 and the Martens hardness HM2 is preferably 0.05 N / mm 2 The following.

[0094] In order to increase the contact pressure, a method such as increasing the hardness of the blade surface by surface treatment is performed, but in this case, the hardness of the treatment layer and the inside of the blade changes, thereby promoting fragmentation from the boundary portion of the hardness. When the absolute value of the difference between HM1 and HM2 is 0.10 N / mm 2 The following, the hardness difference between the inside and the surface is small, and edge fragmentation that tends to occur in the hardness boundary region when increasing the contact pressure in a low-temperature environment can be suppressed.

[0095] It is assumed that a line segment at a distance of 10 μm from the top side edge is drawn parallel to the top side edge on the top surface of the elastic member including polyurethane, the length of the line segment is represented by L, and the points at 1 / 8L, 1 / 2L, and 7 / 8L from one end side of the line segment are represented by P0, P1, and P2, respectively. A square with a side length of 1 μm on the top surface, one side of which is parallel to the line segment and which also has P0, P1, and P2 as the respective centers of gravity is used as the observation region. In each observation region, the proportion ((S2 / S1)×100)) of the number (S2) of hard segments with a circular equivalent diameter of 40 nm or less in the total number (S1) of hard segments is 92% or more, and S1 is 300 or more and 1500 or less (see Figure 7 ).

[0096] At every 1 μm2 When the total number S1 of the hard segments is 300 or more and the proportion [(S2 / S1)×100)] of the number (S2) of hard segments having a circular equivalent diameter of 40 nm or less is 92% or more, aggregation of the hard segments is suppressed, and a state in which the hard segments are finely dispersed therein is achieved. Therefore, the hard segment portion is not easily detached from the soft segment portion, and chipping at the edge of the cleaning blade can be suppressed. When the total number S1 of the hard segments is 1500 or less, the cleaning blade does not become too hard and has good followability to the image bearing member, thereby suppressing the occurrence of poor cleaning.

[0097] [(S2 / S1)×100)] is preferably 95% or more and 100% or less.

[0098] S1 is preferably 630 or more and 1380 or less.

[0099] Assume that a line segment at a distance of 0.5 mm from the top side edge is drawn parallel to the top side edge on the top surface of the elastic member including polyurethane. The length of the line segment is represented by L', and the points at 1 / 8L', 1 / 2L', and 7 / 8L' from one end side of the line segment are represented by P0', P1', and P2', respectively. Among them

[0100] The detected amount of all ions is represented by M1,

[0101] The integrated intensity of the peak of the extracted ion thermogram corresponding to the m / z value in the range of 380.5 to 381.5 derived from polymeric MDI is represented by M2,

[0102] The integrated intensity of the peak of the extracted ion thermogram corresponding to the m / z value in the range of 249.5 to 250.5 derived from 4,4'-MDI is represented by M3, and

[0103] The integrated intensity of the peak of the extracted ion thermogram corresponding to the m / z value in the range of 749.5 to 750.5 in the isocyanurate form of 4,4'-MDI is represented by M4,

[0104] These M1, M2, M3, and M4 are obtained when the samples sampled at P0', P1', and P2' are heated to 1000 °C at a heating rate of 10 °C / second by using a direct inlet type mass spectrometer in which the samples are heated and vaporized in the ionization chamber and the sample molecules are ionized.

[0105] M2 / M1 is 0.001 to 0.015,

[0106] M3 / M1 is 0.04 to 0.10, and

[0107] M4 / M1 is 0.001 or less.

[0108] The polyurethane preferably comprises the reaction product of a composition comprising an isocyanate compound and an alcohol, the isocyanate compound comprising a diisocyanate and at least a trifunctional polyisocyanate, and the alcohol comprising at least a trifunctional polyalcohol. For example, the polyurethane preferably contains the crosslinking reaction product (allophanate reactant) of a polymer of a composition comprising polymeric MDI represented by the following chemical formula (1) and 4,4'-MDI represented by the following chemical formula (2) and a trifunctional alcohol.

[0109] An alcohol having three hydroxyl groups in one molecule is called a trifunctional alcohol.

[0110] Polymeric MDI is represented by the following chemical formulas (1) and (1)'.

[0111] Preferably, n in the chemical formula (1)' is 1 or more and 4 or less.

[0112] When n in the chemical formula (1)' is 1, the chemical formula (1) is obtained.

[0113] [C1]

[0114]

[0115] 4,4'-MDI is represented by the following chemical formula (2).

[0116] [C2]

[0117]

[0118] The isocyanurate form of 4,4'-MDI is represented by the following chemical formula (3).

[0119] [C3]

[0120]

[0121] When M2 / M1 is 0.001 or more, a structure having low crystallinity derived from polymeric MDI, for example, is introduced into the polyisocyanate forming the hard segment, aggregation of the hard segment is suppressed, and the hard segment can be finely dispersed. Therefore, the hard segment can be prevented from peeling off from the soft segment portion, and edge chipping caused by the peeling of the hard segment can be suppressed. When M2 / M1 is 0.015 or less, the crosslinking amount derived from polymeric MDI is within an appropriate range so that the hardness does not become too large, and thus, the followability to the image bearing member is good, and the occurrence of poor cleaning can be suppressed.

[0122] M2 / M1 is preferably 0.003 to 0.014.

[0123] Since a bifunctional polyisocyanate has a structure that promotes chain extension compared to a trifunctional or higher polyisocyanate, the molecular weight is likely to increase, and abrasion resistance can be improved. Among bifunctional polyisocyanates, 4,4'-MDI is preferred because the reactivity of the two isocyanate groups is the same and the molecular weight is likely to increase.

[0124] A compound having one isocyanate group in the molecule is represented as a monofunctional isocyanate, and a compound having n isocyanate groups is represented as an n-functional isocyanate.

[0125] When M3 / M1 is 0.04 or more (where M3 is the integrated intensity of the peak of the extracted ion chromatogram corresponding to the m / z value in the range of 249.5 to 250.5 derived from 4,4'-MDI), the molecular weight is likely to increase during the curing reaction, and abrasion resistance can be improved. Since 4,4'-MDI has a highly symmetric structure and a large amount of 4,4'-MDI, the hard segments tend to aggregate. Therefore, by setting M3 / M1 to 0.10 or less, aggregation of the hard segments can be suppressed, and edge chipping caused by detachment of the hard segments can be suppressed.

[0126] M3 / M1 is preferably from 0.04 to 0.08.

[0127] By introducing the isocyanurate form structure of 4,4'-MDI, the effect of suppressing aggregation of only the hard segments of 4,4'-MDI can be obtained, and edge chipping caused by detachment of the hard segments can be suppressed. However, an excessive isocyanurate form structure of 4,4'-MDI increases stress relaxation, and as a result, the cleanliness deteriorates due to a decrease in contact pressure. Therefore, M4 / M1 is set to 0.001 or less, thereby suppressing deterioration of cleanliness.

[0128] Assume that a line segment parallel to the top-side edge and 0.5 mm away from the top-side edge is drawn on the top surface, where the length of the line segment is represented by L', and the points at 1 / 8L', 1 / 2L', and 7 / 8L' from one end side of the line segment are represented by P0', P1', and P2', respectively. In the DSC chart obtained by differential scanning calorimetry of samples taken at P0', P1', and P2', respectively,

[0129] the peak temperature of the only endothermic peak is 200 °C or higher,

[0130] the melting start temperature of the endothermic peak is 175 °C or higher, and

[0131] the difference between the melting start temperature and the peak temperature is 15 °C or higher.

[0132] The polyurethane preferably includes a crosslinked reaction product (urethane) of a polymer of a composition containing polymeric MDI represented by chemical formula (1) and 4,4'-MDI represented by chemical formula (2) and a trifunctional alcohol.

[0133] As described above, in the case of promoting the aggregation of hard segments, edge chipping is caused, but when there is an endothermic peak below 200 °C in the DSC chart obtained by differential scanning calorimetry, a melting phenomenon of hard segment aggregation is exhibited. In other words, in a state where the aggregation of hard segments is suppressed, the melting phenomenon does not become obvious, and thus an endothermic peak below 200 °C does not appear.

[0134] Furthermore, in order to suppress edge chipping caused by the detachment of hard segments, the hard segments must be in a finely dispersed state. The molecular motion of the hard segments in this finely dispersed state exists as a broad endothermic peak derived from hydrogen bonds in the polyurethane structure. For the broad endothermic peak, the melting start temperature of the endothermic peak is 175 °C or higher, and the peak top temperature of the only endothermic peak is 200 °C or higher. Further, in the broad peak, the difference between the melting start temperature and the peak top temperature is 15 °C or higher.

[0135] Regarding the differential scanning calorimetry of the polyurethane, first, by performing an annealing process at 80 °C for 4 hours, the peak derived from the aggregation of soft segments can be removed, and the endothermic peak derived from hard segments can be accurately measured.

[0136] The peak top temperature of the only endothermic peak is preferably 210 °C or higher. Further, it is preferably 213 °C or lower.

[0137] The melting start temperature of the endothermic peak is preferably 182 °C or higher. Further, it is preferably 190 °C or lower.

[0138] The difference between the melting start temperature and the peak top temperature is preferably 22 °C or higher. Further, it is preferably not higher than 28 °C.

[0139] [Support member]

[0140] The material of the support member constituting the cleaning blade of the invention is not particularly limited, and examples thereof include the following materials. Metal materials such as steel plates, stainless steel plates, galvanized steel plates, chromium-free steel plates, and resin materials such as 6-nylon and 6,6-nylon. Further, the structure of the support member is not particularly limited. As Figure 2 shown, one end of the elastic member of the cleaning blade is supported by the support member.

[0141] [Elastic member]

[0142] The polyurethane elastomer constituting the elastic member is mainly obtained from raw materials such as polyols, chain extenders, polyisocyanates, catalysts, and other additives. Hereinafter, these raw materials will be described in detail.

[0143] Examples of the polyol include the following. Polyester polyols such as polyethylene adipate glycol, polybutylene adipate glycol, polyhexamethylene adipate glycol, (polyethylene / polypropylene) adipate glycol, (polyethylene / polybutylene) adipate glycol, and (polyethylene / polyneopentylene) adipate glycol; polycaprolactone-based polyols obtained by ring-opening polymerization of caprolactone; polyether polyols such as polyethylene glycol, polypropylene glycol, and polybutylene glycol; and polycarbonate diol, and these can be used alone or in combination of two or more. Among the above polyols, polyester polyols of adipate are preferably used because polyurethane elastomers having excellent mechanical properties can be obtained.

[0144] In particular, those having a diol with four or more carbon atoms are more preferably used, such as polybutylene adipate glycol and polyhexamethylene adipate glycol. Further, polyols having different numbers of carbon atoms of the diol are preferably used in combination, such as polybutylene adipate glycol and polyhexamethylene adipate glycol. The presence of different types of polyols suppresses the crystallization of the soft segment, and thus the aggregation of the hard segment can be suppressed.

[0145] As the chain extender, diols and polyols capable of extending the polyurethane elastomer chain can also be used. Examples of the diol include the following. Ethylene glycol (EG), diethylene glycol (DEG), propylene glycol (PG), dipropylene glycol (DPG), 1,4-butanediol (1,4-BD), 1,6-hexanediol (1,6-HD), 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, benzenedimethanol (p-benzenedimethanol), and triethylene glycol. Examples of the tri- or higher-functional polyol include trimethylolpropane, glycerin, pentaerythritol, and sorbitol. These can be used alone or in combination of two or more.

[0146] Introducing crosslinking can be one of the methods for improving the elastic modulus of the polyurethane elastomer. As a method for introducing crosslinking, it is preferable to use a polyol as the chain extender.

[0147] Further, when the number of branches is too large, it is difficult to react all the hydroxyl groups, and it is difficult to obtain the desired degree of crosslinking. Therefore, among the polyols, trifunctional alcohols are more preferably used. Among the trifunctional alcohols, trimethylolpropane (TMP) is more preferably used, which has a methylene skeleton adjacent to the hydroxyl group, thereby generating a molecular flexible crosslinked structure and also exerting an effect of suppressing the crystallinity of the hard segment.

[0148] The concentration of the trifunctional alcohol calculated by the following formula (2) is preferably 0.22 to 0.39 mmol / g. A concentration of 0.22 mmol / g or more is very effective for suppressing the aggregation of the hard segments and can further suppress the edge chipping of the cleaning blade. When the concentration is 0.39 mmol / g or less, the elastic modulus introduced by crosslinking does not become too high, and thus, the followability to the image-bearing member is very good, and the occurrence of poor cleaning can be further suppressed.

[0149] Formula (2): Concentration of trifunctional alcohol (mmol / g) =

[0150] [Amount of trifunctional alcohol (g) / Molecular weight of trifunctional alcohol × 1000] / [Mass of polyurethane (g)]

[0151] Examples of the polyisocyanate include the following. 4,4'-Diphenylmethane diisocyanate (4,4'-MDI), polymeric MDI, 2,4-toluene diisocyanate (2,4-TDI), 2,6-toluene diisocyanate (2,6-TDI), xylylene diisocyanate (XDI), 1,5-naphthalene diisocyanate (1,5-NDI), p-phenylene diisocyanate (PPDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane diisocyanate (hydrogenated MDI), tetramethylxylylene diisocyanate (TMXDI), and carbodiimide-modified MDI. Among them, 4,4'-MDI is preferred because the two isocyanate groups have the same reactivity and high mechanical properties can be obtained. Further, since the polyisocyanate forming the hard segment itself has a branched structure, it is more preferred to use in combination a polyisocyanate having three or more functional groups with a very high effect of suppressing the aggregation of the hard segments, for example, polymeric MDI.

[0152] As the catalyst, a catalyst usually used for curing polyurethane elastomers can be used, for example, a tertiary amine catalyst, and specific examples thereof include the following. Amino alcohols such as dimethylethanolamine, N,N,N'-trimethylaminopropyl ethanolamine, and N,N'-dimethylhexanolamine; trialkylamines such as triethylamine; tetraalkyl diamines such as N,N,N'N'-tetramethyl-1,3-butanediamine; triethylenediamine, piperazine-based compounds, and triazine-based compounds. Further, organic acid salts of metals such as potassium acetate and basic potassium octanoate can also be used. Further, a metal catalyst usually used for urethanation, for example, dibutyltin dilaurate, can also be used. These can be used alone or in combination of two or more.

[0153] As needed, additives such as pigments, plasticizers, waterproofing agents, antioxidants, ultraviolet absorbers, and light stabilizers can be added to the raw materials constituting the elastic member.

[0154] <Method for manufacturing a cleaning blade>

[0155] The method for manufacturing a cleaning blade according to the present invention is not particularly limited, and a suitable method can be selected from known methods. For example, by disposing a support member in a mold for a cleaning blade, then injecting a polyurethane raw material composition into the cavity and heating and curing it, a cleaning blade in which a plate-shaped blade member and a support member are integrated can be obtained. Further, a method can also be used in which a polyurethane elastomer sheet is separately molded from a polyurethane raw material composition, a strip-shaped elastic member is cut out therefrom, the bonding portion of the elastic member is stacked on a support member coated or pasted with an adhesive, and bonding is performed by heating and pressing.

[0156] By performing surface treatment, the elastic modulus measured by SPM on the top surface of the cleaning blade can be increased. The light source used in the surface treatment process generates ultraviolet rays. In particular, it is preferable that the wavelength of the maximum emission peak is around 254 nm, for example, in the range of 254 ± 1 nm. This is because ultraviolet rays in the above wavelength range or having the above wavelength can effectively generate reactive oxygen species that modify the polyurethane surface. When there are multiple ultraviolet emission peaks, it is preferable that one of them is around 254 nm.

[0157] The intensity of the light emitted from the light source is not particularly limited, and values measured by a spectral illuminometer (USR-40V / D, manufactured by Ushio, Inc.) or an ultraviolet cumulative photometer (UIT-150-A, UVD-S254, VUV S172, and VUV-S365, manufactured by Ushio, Inc.) etc. can be adopted. Further, the cumulative light energy of the ultraviolet rays irradiated onto the polyurethane in the surface treatment process can be appropriately selected according to the effect of the surface treatment to be obtained. Irradiation can be performed by changing the irradiation time of the light from the light source, the output of the light source, and the distance from the light source, etc., and these can be determined to obtain a desired cumulative light energy such as 10000 mJ / cm 2 .

[0158] The cumulative light energy of the ultraviolet rays emitted to the conductive member can be calculated by the following method.

[0159] UV cumulative light energy (mJ / cm 2 ) = UV intensity (mW / cm 2 ) × irradiation time (seconds)

[0160] As a light source that emits ultraviolet rays, for example, a high-pressure mercury lamp or a low-pressure mercury lamp can be appropriately used. These light sources are preferred because they can stably emit ultraviolet rays having a suitable wavelength and have little attenuation due to the irradiation distance, and can easily and uniformly irradiate the entire surface.

[0161] <Processing Cartridge and Electrophotographic Image Forming Apparatus>

[0162] The cleaning blade can be used by incorporating it into a processing cartridge configured to be detachably mounted on an electrophotographic image forming apparatus. Specifically, the cleaning blade according to the present embodiment can be used, for example, in a processing cartridge including an image bearing member as a member to be cleaned and configured such that the cleaning blade can clean the surface of the image bearing member. Such a processing cartridge contributes to stable formation of high-quality electrophotographic images.

[0163] Furthermore, an electrophotographic image forming apparatus according to an aspect of the present invention includes an image bearing member such as a photosensitive member, and is configured such that the cleaning blade can clean the surface of the image bearing member, and the cleaning blade is the cleaning blade of the present embodiment. Such an electrophotographic image forming apparatus can stably form high-quality electrophotographic images.

[0164] Examples

[0165] The present invention will be described below with reference to production examples, examples, and comparative examples, but the present invention is not limited to these examples. Except for those shown in the examples and comparative examples, reagents or industrial chemicals are used as raw materials.

[0166] In the examples, the integrally formed cleaning blade shown was manufactured and evaluated. Figure 1 The formulations and evaluation results of the respective examples are shown in Tables 1 to 4.

[0167] <Example 1>

[0168] [Supporting Member]

[0169] A galvanized steel sheet having a thickness of 1.6 mm was prepared and processed to obtain Figure 2 the supporting member having an L-shaped cross section represented by reference numeral 3 in.

[0170] A polyurethane-metal single-layer adhesive (trade name; CHEMLOK 219, manufactured by LORD Corporation) was applied to the portion of the supporting member that contacts the elastic member.

[0171] [Preparation of Raw Materials for Elastic Member]

[0172] A prepolymer having an NCO content of 10.0% by mass was obtained by reacting the following components at 80°C for 3 hours:

[0173] 353.6 g of 4,4'-diphenylmethane diisocyanate (trade name: MILLIONATE MT, manufactured by Tosoh Corporation) (hereinafter referred to as 4,4'-MDI), and

[0174] 10.0 g of polymeric MDI (trade name: MILLIONATE MR-400, manufactured by Tosoh Corporation) (hereinafter referred to as MR400) was used as the isocyanate, and

[0175] 636.4 g of adipic acid butanediol ester polyester polyol with a number average molecular weight of 2500 (trade name: NIPPOLLAN 3027, manufactured by Tosoh Corporation) (hereinafter referred to as PBA2500) was used as the polyol.

[0176] Subsequently, as the curing agent,

[0177] 7.1 g of 1,4-butanediol (manufactured by Tokyo Chemical Industry Co., Ltd.) (hereinafter referred to as 1,4-BD),

[0178] 27.1 g of glycerol (manufactured by Tokyo Chemical Industry Co., Ltd.),

[0179] 250.9 g of adipic acid hexanediol ester polyester polyol with a number average molecular weight of 1000 (trade name: NIPPOLLAN 164, manufactured by Tosoh Corporation) (hereinafter referred to as PHA1000),

[0180] 0.13 g of Polycat 46 (trade name, manufactured by Air Products Japan, Inc.), and

[0181] 0.55 g of N,N'-dimethylhexanolamine (trade name: KAOLIZER No. 25, manufactured by Kao Corporation) (hereinafter referred to as No. 25) were mixed to prepare the curing agent.

[0182] The polyurethane elastomer composition was obtained by adding the mixture (curing agent) to the above prepolymer and mixing.

[0183] The adhesive application part of the support member was configured to protrude into the cavity of the cleaning blade forming die. Then, the polyurethane elastomer composition was injected into the cleaning blade forming die, cured at 130 °C for 2 minutes, and then demolded to obtain an integrally molded body of polyurethane and the support member.

[0184] Before injecting the polyurethane elastomer composition, the mold was coated with mold release agent A. Mold release agent A is a mixture of 5.06 g of ELEMENT14 PDMS 1000-JC (trade name, manufactured by Momentive Performance Materials Inc.), 6.19 g of ELEMENT14 PDMS 10K-JC (trade name, manufactured by Momentive Performance Materials Inc.), 3.75 g of SR1000 (trade name, manufactured by Momentive Performance Materials Inc.), and 85 g of EXXSOL DSP145 / 160.

[0185] The integrally molded body was appropriately cut so that the angle of the edge was 90°, and the distances of the polyurethane in the lateral direction, thickness direction, and longitudinal direction were 7.5 mm, 1.8 mm, and 240 mm, respectively. The obtained cleaning blade was evaluated by the following method.

[0186] [Method for measuring elastic modulus]

[0187] The elastic modulus determined by SPM was measured by the following method. As the scanning probe microscope (SPM), MFP-3D-Origin (Oxford Instruments Co., Ltd.) was used.

[0188] The method for preparing the measurement sample was as follows.

[0189] Assume that a first line segment with a length L and a distance of 10 μm from the top-side edge is drawn parallel to the top-side edge on the top surface of the obtained cleaning blade. Three measurement samples with a side length of 2 mm and having as the center of gravity points P0, P1, and P2 at distances of 1 / 8L, 1 / 2L, and 7 / 8L from one end side of the line segment and one side parallel to the first line segment were cut out. Next, polyurethane thin slices with a side length of 100 μm and a thickness of 1 μm, having P0, P1, and P2 as the center of gravity and one side parallel to the first line segment, were cut from each measurement sample at -50 °C using a cryostat (UC-6 (trade name), manufactured by Leica Microsystems, Inc.). In this way, three measurement samples were prepared. Each of the obtained measurement samples was placed on a smooth silicon wafer and allowed to stand for 24 hours in an environment at room temperature of 25 °C and humidity of 50%.

[0190] Next, a silicon wafer with a measurement sample placed thereon is set on the SPM stage, and SPM observation is performed. On this SPM apparatus, the spring constant and the proportional constant (inverse constant) of a silicon cantilever (trade name: OMCL-AC160, manufactured by Olympus Corporation, tip radius of curvature: 8 nm) are pre-checked by the thermal noise method, and the following values are obtained (spring constant: 30.22 nN / nm, proportional constant (inverse constant): 82.59 nm / V).

[0191] In addition, the cantilever is pre-tuned, and the resonance frequencies of the cantilever are obtained (285 kHz (first order) and 1.60 MHz (higher order)).

[0192] The SPM measurement mode is set to the AM-FM mode, the free amplitude of the cantilever is set to 3 V (first order) and 25 mV (higher order), the setpoint amplitude is set to 2 V (first order), and scanning is performed in a square field of view of 70 μm × 70 μm under the conditions of a scanning speed of 1 Hz, the number of scanning points in the vertical direction of 256, and the number of scanning points in the horizontal direction of 256, and a phase image is obtained. The field of view position is selected such that P0, P1, and P2 of each measurement sample are present at the center of the field of view and parallel to the first line segment.

[0193] Based on the obtained phase image, positions in the measurement sample to measure the elastic modulus by force curve measurement are specified. That is, 70 points centered on P0, P1, and P2 respectively are specified on the first line segment at an interval (spacing) of 1 μm.

[0194] After that, force curve measurement in the contact mode is performed once at all points. Force curves are obtained under the following conditions.

[0195] In the force curve measurement, a piezoelectric element that is a driving source of the cantilever is controlled so that the tip of the cantilever contacts the sample surface and retracts when the deflection reaches a certain value. The retraction point at this time is called the trigger value, and the voltage degree of the deflection voltage increase from the start of the force curve where the cantilever retracts is represented.

[0196] In this measurement, force curve measurement is performed with the trigger value set to 0.2 V. As other force curve measurement conditions, the distance from the tip position of the cantilever in the standby state to the retraction point of the cantilever at the trigger value is set to 500 nm, and the scanning speed is set to 1 Hz (the speed of the probe going back and forth once).

[0197] After that, the obtained force curves are each fitted based on Hertz theory, and the elastic modulus is calculated.

[0198] The elastic modulus (Young's modulus) according to Hertz theory is calculated by the following formula (*1)

[0199] Calculation formula (*1)

[0200] F = (4 / 3)E*R 1 / 2 d 3 / 2

[0201] Here, F is the force applied to the sample by the cantilever when the cantilever retracts, E* is the composite elastic modulus, R is the radius of curvature of the tip of the cantilever (8 nm), and d is the amount of deformation of the sample when the cantilever retracts.

[0202] Here, d is calculated by the following formula (*2).

[0203] Calculation formula (*2)

[0204] d = Δz - D.

[0205] Δz is the displacement of the piezoelectric element from when the tip of the cantilever contacts the sample until the cantilever retracts, and D is the warping amount of the cantilever when the cantilever retracts.

[0206] Here, D is calculated by the following formula (*3).

[0207] Calculation formula (*3)

[0208] D = α·ΔV 偏转

[0209] In the calculation formula (*3), α represents the proportionality constant (inverse constant) of the cantilever, and ΔV 偏转 represents the change amount of the deflection voltage from when the cantilever contacts the sample to the retraction point.

[0210] In addition, F is calculated by the following formula (*4).

[0211] Calculation formula (*4)

[0212] F = κ·D

[0213] K is the spring constant of the cantilever.

[0214] Since ΔV 偏转 and Δz are actually measured values, E* in the calculation formula (*1) can be obtained from the calculation formulas (*1) to (*4). Further, the elastic modulus (Young's modulus) Es to be obtained can be obtained by the following formula (*5).

[0215] Calculation formula (*5)

[0216] 1 / E* = [(1 - Vs 2 ) / Es] - [(1 - Vi 2 ) / Ei]

[0217] Vs: Poisson's ratio of the sample (fixed at 0.33 in this embodiment)

[0218] Vi: Poisson's ratio at the tip of the cantilever (in this embodiment, the value of silicon is used).

[0219] Ei: Young's modulus at the tip of the cantilever (in this embodiment, the value of silicon is used).

[0220] The elastic modulus is taken as the average value of the elastic modulus values calculated from the force curves of 70 points at 3 positions (i.e., a total of 210 points). Additionally, the coefficient of variation is calculated from the average value and standard deviation of the elastic modulus values of the total 210 points. The calculated values are shown in Table 1.

[0221] [Measurement method for the size and number of hard segments]

[0222] The measurement sample is prepared in the same manner as the preparation method of the measurement sample described in the above measurement method of the elastic modulus. Further, except that the size of the field of view is set to 1 μm × 1 μm, three phase images (256 gray-scale images) are obtained in the same manner as the method described in the above measurement method of the elastic modulus.

[0223] Each of the obtained phase images is binarized using an image processing analysis system (trade name: Luzex-AP, manufactured by Nireco Corporation). Specifically, the phase image is binarized using the binarization setting function of the image processing analysis system. The threshold value in the binarization setting function is set to 85 (the 85th out of 256 gray-scales). Through this operation, a binarized image is obtained, in which the soft segments are shown in black and the hard segments are shown in white. Figure 11 (a) shows one of the binarized images obtained from the elastic member according to Example 1.

[0224] Next, the number and size of the hard segments in the obtained binarized image are measured using the above image processing analysis system. The number of hard segments is measured using the "particle number" parameter, and the size of the hard segments is measured using the "equivalent circle diameter" parameter.

[0225] In each of the three square observation regions on the top surface having P0, P1, and P2 as the centroids, a side length of 1 μm, and one side parallel to the line segment, the ratio [(S2 / S1) × 100)] of the number (S2) of hard segments with an equivalent circle diameter of 40 nm or less to the total number (S1) of hard segments is calculated, and the obtained results are shown in Table 1.

[0226] [Measurement method for Martens hardness]

[0227] The Martens hardness can be measured by the following method.

[0228] Assume that a line segment 10 μm away from the edge is drawn parallel to the edge on the top surface of the elastic member. The length of the line segment is represented by L, and the Martens hardness of the point P1 at 1 / 2L from one end side of the line segment is represented by HM1.

[0229] Furthermore, assume that when the bisector of the angle formed by the main surface and the top surface is drawn on the cross-section including P1 and orthogonal to the top surface and the top-side edge, the Martens hardness of the elastic member measured at a position 500 μm away from the top-side edge on the bisector is represented by HM2 (see Figure 6 ).

[0230] The numerical value of |HM1 - HM2| is shown in Table 1.

[0231] Microhardness tester: manufactured by Shimadzu Corporation, model: DUH-211S

[0232] Measurement environment: 23 ± 5 °C

[0233] Measurement indenter: triangular pyramid indenter 115° (ridge angle 115°)

[0234] Measurement mode: depth setting test

[0235] Depth setting: 2 μm

[0236] Load speed: 0.03 mN / s

[0237] Holding time: 5 s

[0238] Calculation formula: Martens hardness = 1000F / 26.43h 2 [N / mm 2

[0239] F: test force (mN), h: indentation depth (μm)

[0240] [Measurement method for polymeric MDI, 4,4'-MDI, and the isocyanurate form of 4,4'-MDI]

[0241] Measurement is carried out by the direct injection method (DI method), in which the sample is directly introduced into the ion source without passing through gas chromatography (GC).

[0242] The device used is POLARIS Q manufactured by Thermo Fisher Scientific Inc., and a direct exposure probe (DEP) is used.

[0243] Assume that a line segment is drawn parallel to the top-side edge on the top surface at a distance of 0.5 mm from the top-side edge. Use a biocutter to scrape off the polyurethane at points (referred to as P0', P1', and P2' respectively) at distances of 1 / 8L', 1 / 2L', and 7 / 8L' from one end side of the line segment, where L' is the length of the line segment. Fix samples of approximately 0.1 μg each taken at P0', P1', and P2' to the wire located at the tip of the probe and directly insert them into the ionization chamber. Then, rapidly heat from room temperature to 1000 °C at a constant heating rate (10 °C / second) and detect the vaporized gas by a mass spectrometer.

[0244] Take the sum of the integrated intensities of all peaks in the obtained total ion current thermogram as the detected amount M1 of all ions.

[0245] Let the integrated intensity of the peak in the extracted ion thermogram corresponding to the m / z value in the range of 380.5 - 381.5 derived from polymeric MDI be represented by M2.

[0246] Let the integrated intensity of the peak in the extracted ion thermogram corresponding to the m / z value in the range of 249.5 - 250.5 derived from 4,4'-MDI be represented by M3, and

[0247] Let the integrated intensity of the peak in the extracted ion thermogram corresponding to the m / z value in the range of 749.5 - 750.5 in the isocyanurate form of 4,4'-MDI be represented by M4, and calculate M2 / M1, M3 / M1, and M4 / M1. Take the arithmetic mean of the values obtained in each of P0', P1', and P2' as the M2 / M1 value, M3 / M1 value, and M4 / M1 value in the present invention.

[0248] [Method for measuring the type and concentration of trifunctional alcohol]

[0249] Detect trifunctional alcohol by thermal decomposition GC / MS. The measurement conditions are as follows.

[0250] Sampling position: Assume that a line segment is drawn parallel to the top-side edge on the top surface at a distance of 0.5 mm from the top-side edge. Use a biocutter to scrape off the polyurethane at points (referred to as P0', P1', and P2' respectively) at distances of 1 / 8L', 1 / 2L', and 7 / 8L' from one end side of the line segment, where L' is the length of the line segment.

[0251] The samples taken at P0', P1', and P2' are measured by the following method. Then, take the arithmetic mean of the values obtained in each of the samples at P0', P1', and P2' as the measured value in the present invention.

[0252] Apparatus:

[0253] Pyrolysis device: Trade name: EGA / PY-3030D, manufactured by Frontier Laboratories Ltd.

[0254] Gas chromatograph: TRACE1310 gas chromatograph, manufactured by Thermo Fisher Scientific Inc.

[0255] Mass spectrometer: ISQLT, manufactured by Thermo Fisher Scientific Inc.

[0256] Pyrolysis temperature: 500 °C

[0257] GC column: Inner diameter: 0.25 mm × 30 m, stainless steel capillary column

[0258] Stationary phase: 5% phenylpolydimethylsiloxane

[0259] Temperature rising condition: Keep the temperature at 50 °C for 3 minutes, then raise the temperature to 300 °C at a rate of 8 °C / minute.

[0260] MS condition: Mass number range m / z 10 - 650

[0261] Scanning speed: 1 second / scanning

[0262] The types of trifunctional alcohols are qualitative in GC / MS. A calibration curve is prepared by GC analysis of known concentrations of the trifunctional alcohol types determined qualitatively, and quantification is performed from the GC peak area ratio.

[0263] <Measurement of DSC>

[0264] According to the plastic transition temperature test method of Japanese Industrial Standard (JIS) K7121, DSC measurement is performed using a differential scanning calorimeter (trade name: TGA / DSC3+, manufactured by Mettler-Toledo, LLC).

[0265] At this time, weigh 5.0 mg of the sample in an aluminum pan, raise the temperature from room temperature to 80 °C at a rate of 10 °C / minute, then perform annealing for 4 hours, cool to 10 °C at a rate of 5 °C / minute, and then raise the temperature from 10 °C to 250 °C at a rate of 10 °C / minute.

[0266] Calculate the peak temperature of the endothermic peak from the differential curve obtained by differentiating the obtained DSC curve. For the melting start temperature, calculate the temperature of the intersection of the straight line obtained by extending the baseline on the low-temperature side of the endothermic peak to the high-temperature side and the tangent drawn at the point with the maximum gradient on the curve on the low-temperature side of the endothermic peak.

[0267] Assume that a line segment is drawn parallel to the top-side edge on the top surface of the sample at a distance of 0.5 mm from the top-side edge. The length of the line segment is represented by L', and the points at distances of 1 / 8L', 1 / 2L', and 7 / 8L' from one end side of the line segment are represented by P0', P1', and P2', respectively. Samples are taken at P0', P1', and P2' of the sample. Then, the arithmetic mean of the values obtained in the respective samples at P0', P1', and P2' is taken as the measured value in the present invention.

[0268] <Method for manufacturing toner 1>

[0269] Hereinafter, unless otherwise specified, all "parts" are based on mass.

[0270] (Preparation process of aqueous medium 1)

[0271] In a reaction vessel equipped with a stirrer, a thermometer, and a reflux tube, a total of 14.0 parts of sodium phosphate (dodecahydrate, manufactured by Rasa Industries, Ltd.) is placed in 650.0 parts of ion-exchanged water, and while purging with nitrogen, the temperature is maintained at 65 °C for 1.0 hour.

[0272] While stirring at 15,000 rpm using a T.K. homomixer (manufactured by Tokushu Kagaku Kogyo Co., Ltd.), an aqueous calcium chloride solution in which 9.2 parts of calcium chloride (dihydrate) is dissolved in 10.0 parts of ion-exchanged water is added thereto, and an aqueous medium containing a dispersion stabilizer is prepared. Further, 10 mass% hydrochloric acid is added to the aqueous medium to adjust the pH to 5.0, and aqueous medium 1 is obtained.

[0273] (Preparation process of polymerizable monomer composition)

[0274] - Styrene: 60.0 parts

[0275] - C.I. Pigment Blue 15:3: 6.5 parts

[0276] The materials are placed in a grinder (manufactured by Mitsui Miike Machinery Co., Ltd.), and further dispersed for 5.0 hours at 220 rpm using zirconia particles with a diameter of 1.7 mm to prepare a pigment dispersion liquid. The following materials are added to the pigment dispersion liquid.

[0277] - Styrene: 20.0 parts

[0278] - n-Butyl acrylate: 20.0 parts

[0279] - Crosslinking agent (divinylbenzene): 0.3 parts

[0280] - Saturated polyester resin: 5.0 parts

[0281] (Condensate of propylene oxide-modified bisphenol A (2-mole adduct) and terephthalic acid (molar ratio 10:2), glass transition temperature Tg = 68 °C, weight-average molecular weight Mw = 10,000, molecular weight distribution Mw / Mn = 5.12)

[0282] - Fischer-Tropsch wax (melting point 78 °C): 7.0 parts

[0283] The obtained composition was kept at 65 °C and uniformly dissolved and dispersed at 500 rpm using a T.K. homogeneous mixer (manufactured by Tokushu Kagaku Kogyo Co., Ltd.) to prepare a polymerizable monomer composition.

[0284] (Pelletizing process)

[0285] The temperature of the aqueous medium 1 was set at 70 °C. While maintaining the rotation speed of the T.K. homogeneous mixer at 15,000 rpm, the polymerizable monomer composition was added to the aqueous medium 1, and 10.0 parts of tert-butyl peroxyneodecanoate was added as a polymerization initiator. Pelletizing was carried out for 10 minutes while maintaining 15,000 rpm using a stirring device.

[0286] (Polymerization / distillation process)

[0287] After the pelletizing process, the stirrer was replaced with a propeller stirring blade, and polymerization was carried out at 70 °C for 5.0 hours while stirring at 150 rpm. The temperature was raised to 85 °C, and heating was carried out for 2.0 hours to carry out the polymerization reaction.

[0288] After that, the reflux pipe of the reaction vessel was replaced with a cooling pipe, and the slurry was heated to 100 °C to carry out distillation for 6 h to distill out the unreacted polymerizable monomer, thereby obtaining a toner masterbatch dispersion.

[0289] (Polymerization of organosilicon compound)

[0290] In a reaction vessel equipped with a stirrer and a thermometer, a total of 60.0 parts of ion-exchanged water was weighed, and the pH was adjusted to 4.0 using 10 mass% hydrochloric acid. It was heated to 40 °C with stirring.

[0291] After that, 40.0 parts of methyltriethoxysilane as an organosilicon compound was added, and then stirring was carried out for at least 2 hours for hydrolysis. The end point of hydrolysis was visually confirmed that the oil and water did not separate and became a single layer, and the mixture was cooled to obtain an organosilicon compound hydrolysis solution.

[0292] After cooling the obtained toner masterbatch dispersion to a temperature of 55°C, 25.0 parts of a hydrolyzed silicone compound solution was added to initiate the polymerization of the silicone compound. After holding for 15 minutes, the pH was adjusted to 5.5 with a 3.0 mass% aqueous sodium bicarbonate solution. After holding for 60 minutes while continuing stirring at 55°C, the pH was adjusted to 9.5 with a 3.0 mass% aqueous sodium bicarbonate solution, and then held for another 240 minutes to obtain a toner particle dispersion.

[0293] (Cleaning and drying process)

[0294] After completion of the polymerization process, the toner particle dispersion was cooled, hydrochloric acid was added to the toner particle dispersion to adjust the pH to below 1.5, the mixture was stirred for 1 hour, and then solid-liquid separation was performed using a pressure filter to obtain a toner filter cake. It was repulped with ion-exchanged water to form a dispersion again, and then solid-liquid separation was performed using the above filter to obtain a toner filter cake.

[0295] The obtained toner filter cake was dried in a thermostat at 40°C for 72 hours and classified to obtain Toner 1.

[0296] <Evaluation of cleaning performance>

[0297] The cleaning blade 1 as the cleaning blade of the photosensitive drum to be cleaned was introduced into the cyan cartridge of a color laser beam printer (trade name: HP LaserJet Enterprise Color M553dn, manufactured by Hewlett-Packard Co.).

[0298] Furthermore, the toner in the developing machine of the cyan cartridge was completely replaced with the above Toner 1.

[0299] Then, after leaving the printer to stand in a low-temperature and low-humidity environment (temperature 15°C, relative humidity 10%) for 24 hours, an image was formed on 12,500 sheets (as the printable number of sheets) in the same environment (hereinafter referred to as "normal evaluation").

[0300] Furthermore, the used developing machine was replaced with the developing machine of a new cyan cartridge in which all the toner was replaced with Toner 1, and an image was formed again on 12,500 sheets (hereinafter referred to as "2-fold evaluation").

[0301] Furthermore, evaluation was carried out by making a hole in the back of the cartridge and appropriately sucking out the waste toner. The performance of the obtained image was graded according to the following evaluation criteria.

[0302] A: Image defects (stripes on the image) caused by the cleaning blade did not occur in either the normal evaluation or the 2-fold evaluation.

[0303] B: Image defects (stripes on the image) caused by the cleaning blade did not occur in the normal evaluation but occurred very slightly in the 2x evaluation (the stripe length is 5 mm or less).

[0304] C: Image defects (stripes on the image) caused by the cleaning blade did not occur in the normal evaluation but occurred slightly in the 2x evaluation (the stripe length is more than 5 mm and 10 mm or less).

[0305] D: Image defects (stripes on the image) caused by the cleaning blade did not occur in the normal evaluation but occurred in the 2x evaluation (more than 10 mm).

[0306] E: Image defects (stripes on the image) caused by the cleaning blade occurred in both the normal evaluation and the 2x evaluation.

[0307] <Evaluation of the edge chipping of the cleaning blade>

[0308] After completing the above cleaning performance evaluation (2x evaluation), remove the cleaning blade from the cassette and observe it with a digital microscope (trade name: main unit VHX-5000, lens VH-ZST, manufactured by Keyence Corporation) at a magnification of 1000 times.

[0309] Use the tip of the main surface of the elastic member of the cleaning blade as the observation surface, and as Figure 9 shown, install the support member at a 45° angle so that the support member is on the upper side and the tip of the elastic member is on the lower side, and observe the entire area in the longitudinal direction. As Figure 9 shown in the partial enlarged view, measure the maximum value of the distance in the lateral direction of the edge chipping part as the "edge chipping amount", and classify the performance according to the following evaluation criteria.

[0310] A + : Edge chipping did not occur.

[0311] A: The edge chipping amount is less than 0.5 μm.

[0312] B: The edge chipping amount is 0.5 μm or more and less than 1 μm.

[0313] C: The edge chipping amount is 1 μm or more and less than 3 μm.

[0314] D: The edge chipping amount is 3 μm or more.

[0315] <Comprehensive evaluation>

[0316] Based on the grade of the image evaluation of the cleaning performance and the grade of the evaluation result of the edge chipping evaluation of the cleaning blade, the comprehensive evaluation is carried out as follows.

[0317] A: The evaluation result is A / A + 、A / A, A / B, B / A, and B / A + combinations. There were no problems in actual use.

[0318] B: The evaluation results are A / C, C / A, C / A + 、B / B, B / C, and C / B combinations. There were no problems in actual use.

[0319] C: The combination with the evaluation result of C / C.

[0320] D: There is no E in the evaluation result, but there is more than one D.

[0321] E: There is more than one E in the evaluation result.

[0322] <Example 2>

[0323] Except for using 345.5 g of 4,4'-MDI and 20.0 g of MR400 as isocyanates, using 634.5 g of PBA2500 as a polyol, and using 10.7 g of 1,4-BD, 26.9 g of glycerol, and 275.7 g of PHA1000 as curing agents, and also evaluating the cleaning performance for the ordinary toner of a commercial developing machine, it was carried out in the same manner as in Example 1.

[0324] <Example 3>

[0325] Except for using 345.5 g of 4,4'-MDI and 20.0 g of MR400 as isocyanates, using 634.5 g of PBA2500 as a polyol, and using 7.0 g of 1,4-BD, 42.2 g of glycerol, and 302.7 g of PHA1000 as curing agents, it was carried out in the same manner as in Example 1.

[0326] <Example 4>

[0327] Except for using 334.6 g of 4,4'-MDI and 40.0 g of MR400 as isocyanates, using 625.4 g of PBA2500 as a polyol, the amount of NCO being 10.2 mass%, and using 10.9 g of 1,4-BD, 27.5 g of glycerol, and 281.2 g of PHA1000 as curing agents, it was carried out in the same manner as in Example 1.

[0328] <Example 5>

[0329] Except for using 301.9 g of 4,4'-MDI and 80.0 g of MR400 as isocyanates, 618.1 g of PBA2500 as polyol, and 11.6 g of 1,4-BD, 29.4 g of glycerol, and 301.3 g of PHA1000 as curing agents, it was carried out in the same manner as in Example 4.

[0330] <Example 6>

[0331] Except for using 10.9 g of 1,4-BD, 27.5 g of glycerol, and 281.2 g of PHA1000 as curing agents, it was carried out in the same manner as in Example 5.

[0332] <Example 7>

[0333] Except for using 269.2 g of 4,4'-MDI and 120.0 g of MR400 as isocyanates, 610.8 g of PBA2500 as polyol, and 13.8 g of 1,4-BD, 27.7 g of glycerol, and 304.4 g of PHA1000 as curing agents, it was carried out in the same manner as in Example 4.

[0334] <Example 8>

[0335] Except for using 4.1 g of 1,4-BD, 45.6 g of glycerol, and 364.5 g of PHA1000 as curing agents, it was carried out in the same manner as in Example 7.

[0336] <Example 9>

[0337] Except for using 10.9 g of 1,4-BD, 27.5 g of glycerol, and 281.2 g of PHA1000 as curing agents, it was carried out in the same manner as in Example 7.

[0338] <Example 10>

[0339] Except for not using 1,4-BD and using 35.9 g of glycerol and 263.5 g of PHA1000 as curing agents, it was carried out in the same manner as in Example 7.

[0340] <Example 11>

[0341] Except for using 30.8 g of glycerol and 225.9 g of PHA1000 as curing agents, it was carried out in the same manner as in Example 10.

[0342] <Example 12>

[0343] Except for not using glycerin and using 50.3 g of trimethylolpropane (manufactured by Tokyo Chemical Industry Co., Ltd.) (hereinafter referred to as TMP) and 285.0 g of PHA1000 as the curing agent, it was carried out in the same manner as in Example 10.

[0344] <Example 13>

[0345] Except for using 241.4 g of 4,4'-MDI and 150.0 g of polymeric MDI (trade name: MILLIONATE MR-200, manufactured by Tosoh Corporation) (hereinafter referred to as MR200) as the isocyanate, using 608.6 g of PBA2500 as the polyol, and using 50.3 g of TMP and 285.0 g of PHA1000 as the curing agent, it was carried out in the same manner as in Example 12.

[0346] <Example 14>

[0347] Except for using 220.2 g of 4,4'-MDI and 180.0 g of MR400 as the isocyanate, using 599.8 g of PBA2500 as the polyol, and using 50.3 g of TMP and 285.0 g of PHA1000 as the curing agent, it was carried out in the same manner as in Example 12.

[0348] <Example 15>

[0349] Except for using 57.5 g of TMP and 325.7 g of PHA1000 as the curing agent, it was carried out in the same manner as in Example 14.

[0350] <Example 16>

[0351] Except for using 61.1 g of TMP and 346.1 g of PHA1000 as the curing agent, it was carried out in the same manner as in Example 14.

[0352] <Example 17>

[0353] Except for using adipic acid butanediol ester polyester polyol with a number average molecular weight of 1000 (trade name: NIPPOLLAN 4009, manufactured by Tosoh Corporation) (hereinafter referred to as PBA1000) to replace PHA1000 as the curing agent, it was carried out in the same manner as in Example 16.

[0354] <Example 18>

[0355] Except for using 217.5 g of 4,4'-MDI and 180.0 g of MR400 as isocyanates, and using 602.5 g of adipic acid hexanediol ester polyester polyol with a number average molecular weight of 2600 (trade name: NIPPOLLAN 136, manufactured by Tosoh Corporation) (which can also be referred to as PHA2600) to replace PBA2500 as the polyol, it was carried out in the same manner as in Example 16.

[0356] <Example 19>

[0357] Except for using PBA1000 to replace PHA1000 as the curing agent, it was carried out in the same manner as in Example 18.

[0358] <Example 20>

[0359] Except for using 236.5 g of 4,4'-MDI and 180.0 g of MR400 as isocyanates, using 583.5 g of PBA2500 as the polyol, the amount of NCO being 10.8 mass%, and using 64.7 g of TMP and 366.4 g of PHA1000 as the curing agent, it was carried out in the same manner as in Example 16.

[0360] <Example 21>

[0361] Except for using 191.1 g of 4,4'-MDI and 210.0 g of MR200 as isocyanates, using 598.9 g of PBA2500 as the polyol, and using 61.1 g of TMP and 346.1 g of PHA1000 as the curing agent, it was carried out in the same manner as in Example 16.

[0362] <Example 22>

[0363] Except for using 187.5 g of 4,4'-MDI and 220.0 g of MR400 as isocyanates, using 592.5 g of PBA2500 as the polyol, and using 57.5 g of TMP and 325.7 g of PHA1000 as the curing agent, it was carried out in the same manner as in Example 16.

[0364] <Example 23>

[0365] Except for using 163.0 g of 4,4'-MDI and 250.0 g of MR400 as isocyanates, and using 587.0 g of PBA2500 as the polyol, it was carried out in the same manner as in Example 22.

[0366] <Example 24>

[0367] Except for using 50.3 g of TMP and 285.0 g of PHA1000 as curing agents, it was carried out in the same manner as in Example 22.

[0368] <Example 25>

[0369] Except for using 63.8 g of TMP and 255.3 g of PHA1000 as curing agents, it was carried out in the same manner as in Example 24.

[0370] <Example 26>

[0371] Except that the adhesive was a one-component adhesive of polyurethane resin for injection and metal (trade name: METALOC UA, manufactured by Toyo Kagaku Kenkyusho Co., Ltd.), it was carried out in the same manner as in Example 4.

[0372] <Example 27>

[0373] Except for using Release Agent B, it was carried out in the same manner as in Example 4. Release Agent B was a mixture of 4.05 g of ELEMENT14 PDMS 1000-JC (trade name, manufactured by Momentive Performance Materials Inc.), 4.95 g of ELEMENT14 PDMS 10K-JC (trade name, manufactured by Momentive Performance Materials Inc.), 6.00 g of SR1000 (trade name, manufactured by Momentive Performance Materials Inc.), and 85 g of EXXSOL DSP145 / 160.

[0374] <Example 28>

[0375] Except that the adhesive was a one-component adhesive of polyurethane resin for injection and metal (trade name: METALOC UA, manufactured by Toyo Kagaku Kenkyusho Co., Ltd.), it was carried out in the same manner as in Example 27.

[0376] <Example 29>

[0377] Except for using Release Agent C, it was carried out in the same manner as in Example 4. Release Agent C was a fluororesin metal release agent (trade name: Fluoro Surf FG-5093F130-0.5, manufactured by Fluoro Technology Co., Ltd.). The release agent was coated on the mold at 130 °C and dried before injecting the polyurethane composition.

[0378] <Example 30>

[0379] Performed in the same manner as Example 29, except that the adhesive used was a one-component adhesive for injection of polyurethane resin and metal (trade name: METALOC UA, manufactured by Toyo Kagaku Kenkyusho Co., Ltd.).

[0380] <Example 31>

[0381] Performed in the same manner as Example 3, except that the cleaning blade obtained in Example 3 was irradiated with ultraviolet light for 15 seconds using an ultraviolet irradiation treatment device with an ultraviolet intensity of 32.8 mW / cm 2 , and the surface was treated with an ultraviolet cumulative light energy of 492 mJ / cm 2 .

[0382] The light source of the ultraviolet irradiation treatment device was a low-pressure mercury ozone-free lamp (manufactured by Toshiba Lighting&Technology Corporation) using quartz glass containing titanium oxide with a maximum emission peak of 254 nm.

[0383] <Example 32>

[0384] Performed in the same manner as Example 31, except that the cleaning blade obtained in Example 7 was irradiated with ultraviolet light for 60 seconds using an ultraviolet irradiation treatment device with an ultraviolet intensity of 32.8 mW / cm 2 , and the surface was treated with an ultraviolet cumulative light energy of 1968 mJ / cm 2 .

[0385] <Example 33>

[0386] Performed in the same manner as Example 31, except that the cleaning blade obtained in Example 25 was irradiated with ultraviolet light for 120 seconds using an ultraviolet irradiation treatment device with an ultraviolet intensity of 32.8 mW / cm 2 , and the surface was treated with an ultraviolet cumulative light energy of 3936 mJ / cm 2 .

[0387] <Comparative Example 1>

[0388] Performed in the same manner as Example 1, except that 334.7 g of 4,4'-MDI was used as the isocyanate, 665.3 g of PBA2500 was used as the polyol, and 19.4 g of 1,4-BD, 15.5 g of glycerol, and 159.0 g of PBA1000 were used as the curing agents. The binary image obtained from the elastic member according to Comparative Example 1 was in Figure 11Shown in (b).

[0389] <Comparative Example 2>

[0390] Except that, by using an ultraviolet irradiation treatment apparatus with an ultraviolet intensity of 32.8 mW / cm 2 the cleaning blade obtained in Comparative Example 1 was irradiated with ultraviolet rays for 150 seconds, and the surface was treated with an ultraviolet cumulative light energy of 4920 mJ / cm 2 in the same manner as in Comparative Example 1 except for the above treatment.

[0391] <Comparative Example 3>

[0392] A cleaning blade was obtained in the same manner as in Example 1, except that 296.6 g of 4,4'-MDI was used as the isocyanate, 703.4 g of adipic acid butanediol ester polyester polyol (trade name: NIPPOLLAN 4010, manufactured by Tosoh Corporation) with a number average molecular weight of 2000 (hereinafter referred to as PBA2000) was used as the polyol, 62.0 g of 1,4-BD and 15.5 g of glycerol were used as the curing agent, and 0.23 g of No. 25 was used as the catalyst (Polycat 46 was not added). The cleaning blade was secondarily cured at 130°C for 60 minutes, then the top 2 mm of the elastic member was immersed in molten 4,4'-MDI at 80°C for 3 minutes, and then the 4,4'-MDI adhering to the surface of the blade was cleaned with butyl acetate. Then, it was aged for 24 hours to obtain a surface-treated cleaning blade. The obtained cleaning blade was evaluated in the same manner as in Example 1.

[0393] <Comparative Example 4>

[0394] Except that 296.6 g of 4,4'-MDI was used as the isocyanate, 703.4 g of PBA2000 was used as the polyol, 26.5 g of 1,4-BD and 39.7 g of glycerol were used as the curing agent, 0.23 g of No. 25 was used as the catalyst (Polycat 46 was not added), and it was secondarily cured at 130°C for 60 minutes after demolding, the procedure was carried out in the same manner as in Comparative Example 1.

[0395]

[0396]

[0397]

[0398] Table 4

[0399]

[0400] The present invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the present invention. Therefore, the appended claims are intended to disclose the scope of the present invention.

[0401] This application claims priority based on Japanese Patent Application No. 2019-219957 filed on December 4, 2019 and Japanese Patent Application No. 2020-130824 filed on July 31, 2020, and the entire contents thereof are incorporated by reference.

[0402] Explanation of reference numerals

[0403] 1 Cleaning blade

[0404] 2 Elastic member

[0405] 3 Support member

[0406] 4 Main surface facing the member to be cleaned

[0407] 5 Top surface forming a top-side edge together with the main surface

[0408] 6 Member to be cleaned

[0409] R Rotation direction of the member to be cleaned

Claims

1. An electrophotographic cleaning blade, which includes an elastic member containing polyurethane and a support member supporting the elastic member, and which cleans the surface of a moving member to be cleaned by bringing a part of the elastic member into contact with the surface of the member to be cleaned, characterized in that, when defining the side of the cleaning blade that contacts the surface of the member to be cleaned as the tip side of the cleaning blade, the elastic member has at least a plate shape on the tip side, the plate shape having a main surface facing the member to be cleaned and a tip surface that forms a tip side edge together with the main surface; assuming that a first line segment is drawn parallel to the tip side edge on the tip surface at a distance of 10 μm from the tip side edge, where the length of the first line segment is represented by L, and points at 1 / 8L, 1 / 2L, and 7 / 8L from one end side of the first line segment are represented by P0, P1, and P2 respectively, the average value of the elastic modulus of the elastic member measured by using SPM at each of 70 points spaced 1 μm apart on the first line segment centered on each of P0, P1, and P2 on the first line segment is 15 MPa or more and 470 MPa or less; the coefficient of variation of the elastic modulus is 6.0% or less; and The absolute value of the difference between the Martens hardness HM1 of the elastic member measured at the position of P1 and the Martens hardness HM2 of the elastic member measured at a position 500 μm away from the top-side edge on the bisector when assuming that the bisector of the angle formed by the main surface and the top surface is drawn on a cross-section of the elastic member that includes P1 and is orthogonal to the top surface and the top-side edge is 0.10 N / mm 2 as follows.

2. An electrophotographic cleaning blade, which includes an elastic member containing polyurethane and a support member supporting the elastic member, and which cleans the surface of a moving member to be cleaned by bringing a part of the elastic member into contact with the surface of the member to be cleaned, characterized in that, when defining the side of the cleaning blade that contacts the surface of the member to be cleaned as the tip side of the cleaning blade, the elastic member has at least a plate shape on the tip side, the plate shape having a main surface facing the member to be cleaned and a tip surface that forms a tip side edge together with the main surface; assuming that a third line segment is drawn parallel to the tip side edge on the tip surface at a distance of 0.5 mm from the tip side edge, where the length of the third line segment is represented by L', and points at 1 / 8L', 1 / 2L', and 7 / 8L' from one end side of the third line segment are represented by P0', P1', and P2' respectively, and when samples taken at P0', P1', and P2' are heated to 1000 °C at a heating rate of 10 °C / second by using a direct injection type mass spectrometer in which the sample is heated and vaporized in an ionization chamber and the sample molecules are ionized, where the detected amount of all ions is represented by M1, the integrated intensity of the peak of the extracted ion thermogram corresponding to the m / z value in the range of 380.5 - 381.5 derived from polymeric MDI is represented by M2, the integrated intensity of the peak of the extracted ion thermogram corresponding to the m / z value in the range of 249.5 - 250.5 derived from 4,4'-MDI is represented by M3, and the integrated intensity of the peak of the extracted ion thermogram corresponding to the m / z value in the range of 749.5 - 750.5 in the isocyanurate form of 4,4'-MDI is represented by M4, M2 / M1 is 0.001 to 0.015, M3 / M1 is 0.04 to 0.10, and M4 / M1 is less than 0.001, and the concentration of trifunctional alcohol in the polyurethane is 0.22 to 0.39 mmol / g.

3. The electrophotographic cleaning blade according to claim 2, wherein the trifunctional alcohol is trimethylolpropane.

4. A processing cartridge, characterized in that, It has the electrophotographic cleaning blade according to any one of claims 1 to 3.

5. An electrophotographic image forming apparatus, characterized in that, It has the electrophotographic cleaning blade according to any one of claims 1 to 3.

Images