JP2018054816A - Cleaning blade - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning blade which has a higher resistance to cracking.SOLUTION: A cleaning blade 1 includes a plate-shaped blade part 2 made of polyurethane. The blade part 2 has a ridge part 20 to contact with a counter member 9 and has a first blade surface 21 and a second blade surface 22 adjacent to each other sharing the ridge part 20. The first blade surface 21 and the second blade surface 22 have birefringence indexes of 1×10or larger.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a cleaning blade.

  2. Description of the Related Art Conventionally, in an electrophotographic apparatus, a cleaning blade is used to clean the surface of an image carrier such as a photoconductor or a counterpart member such as an intermediate transfer belt. The cleaning blade is generally provided with a polyurethane blade portion having a ridge portion for sliding contact with a mating member. When the ridge line portion of the blade portion is pressed against the surface of the counterpart member, the residual toner on the surface of the counterpart member that moves on the surface is scraped off.

  As this type of cleaning blade, for example, in Patent Document 1, a polyurethane composition is poured into a centrifugal molding machine in which a mold is adjusted to a predetermined temperature to cause a curing reaction, and then aged and heated, cooled and then cut. A cleaning blade using the blade portion thus obtained is disclosed.

Japanese Patent Laying-Open No. 2015-215374

  However, the conventional cleaning blade generates burrs on the ridge line portion during long-term use. When chipping occurs in the ridge line portion, toner slips through the chipping portion, so that the cleaning performance is deteriorated.

  The present invention has been made in view of the above background, and an object of the present invention is to provide a cleaning blade that is more excellent in anti-caking property than conventional ones.

One aspect of the present invention is a cleaning blade used to remove residual toner remaining on the surface of a mating member in an electrophotographic apparatus,
It has a blade made of polyurethane that exhibits a plate-like shape,
The blade part has a ridge line part for contacting the counterpart member, and a first blade surface and a second blade surface that share the ridge line part and are adjacent to each other,
The cleaning blade has a birefringence of 1 × 10 ⁻⁵ or more in both of the first blade surface and the second blade surface.

In the cleaning blade, the birefringence of the first blade surface and the second blade surface adjacent to each other sharing the ridge line portion is 1 × 10 ⁻⁵ or more. For this reason, the cleaning blade is more excellent in anti-bake properties than conventional ones.

2 is a perspective view of a cleaning blade of Example 1. FIG. It is the figure which showed typically the II-II line cross section in FIG. FIG. 3 is an explanatory diagram schematically illustrating an example of a usage state of the cleaning blade of Example 1.

  The cleaning blade is used for removing at least residual toner remaining on the surface of the mating member in the electrophotographic apparatus. More specifically, the cleaning blade scrapes the residual toner on the surface of the mating member carried to the ridgeline by bringing the ridgeline of the blade into contact with the surface of the mating member that moves. Can be used to remove and remove. Specific examples of the electrophotographic apparatus include an electrophotographic copying machine using a charged image, an image forming apparatus such as a printer, a facsimile machine, a multifunction machine, and an on-demand printing machine. Examples of the counterpart member include an image carrier such as a photosensitive drum, an intermediate transfer belt, and the like. The intermediate transfer belt is used to primarily transfer the toner image carried on the image carrier to the belt, and then secondarily transfer the toner image from the belt to a transfer material such as paper. The cleaning blade can be used not only to remove residual toner but also to remove paper fillers.

  The cleaning blade includes a polyurethane blade portion having a plate shape. Specifically, the blade portion can be formed in a rectangular shape having a predetermined thickness, that is, a rectangular parallelepiped shape.

  The blade portion has a ridge line portion for contacting the mating member, and a first blade surface and a second blade surface that share the ridge line portion and are adjacent to each other. That is, the ridge line portion is configured by the intersection of the first blade surface and the second blade surface adjacent to the first blade surface. The first blade surface and the second blade surface are both arranged to face the counterpart member when the blade portion is brought into contact with the counterpart member. Specifically, the first blade surface is a plate surface along a direction perpendicular to the thickness direction of the blade portion (short direction of the blade portion), and the mating member is brought into contact with the mating member. It can be a surface arranged to face the side. Specifically, the second blade surface can be a tip surface (tip surface of the blade portion) along the thickness direction of the blade portion. The second blade surface is arranged to face the counterpart member when the blade portion is brought into contact with the counterpart member.

Here, the birefringence of the first blade surface and the second blade surface is 1 × 10 ⁻⁵ or more. The birefringence of the first blade surface and the birefringence of the second blade surface are physical property values that are related to the crystal state of the polyurethane polymer crystal part (hard segment part) constituting the blade part. When both the birefringence index of the first blade surface and the birefringence index of the second blade surface are within the above range, the crystalline portion of the polyurethane polymer constituting the blade portion is in the direction of the ridge line portion of the blade portion. It is oriented along (the longitudinal direction of the blade portion). Therefore, in this case, local unevenness in the crystal orientation of the polyurethane polymer in the blade portion is reduced, and it is difficult for the entire blade portion to be chipped. Therefore, the anti-choke property of the cleaning blade is improved.

The birefringence is measured as follows. That is, a measurement sample that partially includes the ridge line portion, the first blade surface, and the second blade surface is collected from the central portion that bisects the ridge line portion of the blade portion. The thickness of the measurement sample in the direction perpendicular to the first blade surface and the thickness of the measurement sample in the direction perpendicular to the second blade surface are both adjusted to be in the range of 1.4 to 2.2 mm. Is done. Using a polarizing microscope (manufactured by Leica Microsystems, "DM2500P", a polarizing microscope that can perform the same measurement when it becomes unavailable due to the discontinuation number) Observe the direction perpendicular to the first blade surface. At this time, the direction in which the extinction position is seen is observed as 0 °, and −45 ° is observed as the diagonal position. In addition, when an extinction position is seen in the ridge line direction of the blade part, the ridge line direction of the blade part is set to 0 °. For the observed image, use a compensator (Olympus, “Berek compensato U-CBE”, a compensator that can perform the same measurement when it becomes unavailable due to abandonment). Turn the rotary dial of the compensator at a position of -45 °, and read the scale of the rotary dial when the image turns black. The retardation (phase difference) is obtained from the read angle using the conversion table attached to the compensator. The birefringence of the first blade surface is calculated by dividing the obtained retardation by the thickness of the measurement sample in the direction perpendicular to the first blade surface. Similarly, the direction perpendicular to the second blade surface of the measurement sample is observed, the retardation is obtained from the observed image, and the obtained retardation is divided by the thickness of the measurement sample in the direction perpendicular to the second blade surface. Thus, the birefringence of the second blade surface is calculated.
Here, the conversion table for obtaining the retardation R is obtained by calculation according to the following equation.
R = C · {2 | √ (1-sin ² θ / ε ² ) −√ (1-sin ² θ / ω ² ) |} / (1 / ε ² −1 / ω ² )
However, C is a compensator constant and is represented by the following equation.
C = d × ω × (1 / ε ² −1 / ω ² ) / 2
ω: main refractive index of ordinary light of birefringent material used in compensator ε: main refractive index of extraordinary light of birefringent material used in compensator d: prism thickness of compensator

The birefringence of the first blade surface and the second blade surface is preferably 3 × 10 ⁻⁵ or more, more preferably 5 × 10 ⁻⁵ , from the viewpoint of ensuring the securing of erosion resistance. As described above, more preferably, it can be 7 × 10 ⁻⁵ or more. The birefringence of the first blade surface and the second blade surface is, for example, 1 × 10 ⁻³ or less, preferably 5 × 10 ⁻⁴ or less, more preferably 1 × 10 ⁻⁴ or less. it can.

  The tan δ peak temperature of the blade part is preferably -8 ° C or higher and 8 ° C or lower. When the tan δ peak temperature of the blade portion is 8 ° C. or less, even when exposed to a low temperature environment of about 10 ° C., it is easy to ensure followability of the blade portion to the mating member and to easily prevent toner from slipping through. Become. Further, when the tan δ peak temperature of the blade portion is −8 ° C. or higher, the resilience resilience of the polyurethane blade portion becomes appropriate, and the blade portion is less likely to jump up when sliding against the mating member, and the toner slips through. It becomes easy to suppress. Therefore, according to the above configuration, it is possible to suppress the slipping of the toner from the crushed portion because it is difficult for the ridge portion to chip during long-term use, and furthermore, due to the synergistic effect of ensuring the followability of the blade portion and preventing the blade portion from jumping up. Thus, a cleaning blade advantageous for forming an image with little toner contamination even when used for a long time can be obtained.

  The tan δ peak temperature is determined as follows. Sample collected from blade part <Blade thickness x 2 mm (short direction of blade part) x 30 mm (ridge direction of blade part)> is a dynamic viscoelasticity measuring device (DVE Rheospector manufactured by Rheology) The measurement length is fixed to 20 mm, a sinusoidal distortion with a displacement amplitude of ± 10 μm and a frequency of 10 Hz is applied, and tan δ (loss tangent) in the range of −20 ° C. to 50 ° C. is set at a rate of temperature increase of 3 ° C./min. At every 1 ° C. The temperature at which the obtained tan δ value is maximum (peak) is defined as the tan δ peak temperature.

  The tan δ peak temperature is preferably 7 ° C. or less, more preferably 5 ° C. or less, from the viewpoint of ensuring followability of the blade part in a low temperature environment. The tan δ peak temperature is preferably −7 ° C. or higher, more preferably −5 ° C. or higher, from the viewpoint of ensuring the effect of preventing the blade portion from jumping up.

  If the blade part can take the above-described birefringence range, it can contain various additives as necessary. As said additive, ionic conductive agents, such as potassium salt, an electronic conductive agent, etc. can be illustrated, for example. Potassium salts are unlikely to inhibit the reactivity of the urethane catalyst like ionic conductive agents such as LiTFSI and LiFSI. Therefore, according to this configuration, it is possible to sufficiently ensure rubber elasticity due to the polyurethane of the blade portion, which is advantageous in improving the sag resistance. In addition, it is possible to obtain a cleaning blade that can be scraped off while removing residual toner.

As the anions in the potassium salt, specifically, for _{example, CF 3 SO 2 C 4 F} 9 SO 2 N - < nonafluoro -N - [(trifluoromethane) sulfonyl] butane sulfonyl amide anion>, _(CF 3 SO _{2) 2} N ^- <bis (trifluoromethanesulfonyl) imide _{anion>, (FSO 2) 2 N} - < bis (fluorosulfonyl) imide ^{_{anion>, C 28 H 20 BO 6}} -, AlCl 4 -, Al 2 Cl 7 ⁻ , NO ₃ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , CH ₃ COO ⁻ , CF ₃ COO ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , F ( ^{_{HF) N -, CF 3 CF}} 2 CF 2 CF 2 SO 3 -, (CF 3 CF 2 SO 2) 2 N -, CF 3 CF 2 CF ₂ COO ⁻ , (C ₄ F ₉ SO ₂ ) ₂ N ⁻ , CF ₂ (CF ₂ SO ₂ ) ₂ N ⁻ , CF ₃ SO ₂ NH ₂ ^{— and the} like can be exemplified. These can be used alone or in combination of two or more. The anion in the potassium salt is preferably (CF ₃ SO ₂ ) ₂ N ⁻ , CF ₃ SO ₂ C ₄ F ₉ SO ₂ N ⁻ , C ₂₈ H ₂₀ BO from the viewpoint of ensuring the above effect. _6- ^{and the} like can be used. These can be used alone or in combination of two or more.

  The blade portion can contain a potassium salt of 0.3% by mass or more and less than 10% by mass. According to this configuration, it is easy to ensure the effect of adding potassium salt to the blade portion, and it is easy to suppress bleed and bloom of the potassium salt. In addition, content of potassium salt is a ratio (%) of the mass of the potassium salt contained in a blade part with respect to the whole mass of a blade part.

  The thickness of the blade portion is preferably 1.4 mm or more, more preferably 1.5 mm or more, and still more preferably 1.6 mm or more, from the viewpoint of preventing toner slipping. The thickness of the blade portion is preferably 2.2 mm or less, more preferably 2.1 mm or less, and even more preferably 2 mm or less, from the viewpoint of reducing excessive pressing pressure on the mating member. .

  The cleaning blade may have a support that supports the blade portion. Specifically, a support body can be comprised from electroconductive members, such as a metal plate material. In the cleaning blade, a part of the blade part may be bonded to the support, or a part of the support may be embedded in the blade part. In the former case, it is preferable that a part of the blade portion is integrally joined to the support. The integrally joined state can be obtained by integrally molding the blade part to the support together with the curing of the polyurethane composition when the blade part is formed.

  In the cleaning blade, an adhesive layer can be interposed between the blade portion and the support. The adhesive layer can contain a conductive agent such as an electronic conductive agent and an ionic conductive agent from the viewpoint of imparting conductivity.

  In addition, each structure mentioned above can be arbitrarily combined as needed, in order to acquire each effect etc. which were mentioned above.

  Hereinafter, the cleaning blade of the embodiment will be described with reference to the drawings.

Example 1
The cleaning blade of Example 1 will be described with reference to FIGS. As shown in FIGS. 1 to 3, the cleaning blade 1 of this example is a residual toner remaining on the surface of the counterpart member 9 in the electrophotographic apparatus (not shown, including not only toner but also a toner external additive). It is used for removing. In this example, the counterpart member 9 is specifically a photosensitive drum. The photosensitive drum rotates in the direction of arrow Y shown in FIG.

  The cleaning blade 1 includes a polyurethane blade portion 2 having a plate shape. Polyurethane is a non-foamed material. In this example, the cleaning blade 1 further includes a support body 3 that supports the blade portion 2. The support 3 is made of a metal plate material, and includes a plate-like portion 31 and an attachment portion 32 that is integrally connected to the plate-like portion 31. The attachment part 32 is a part for attaching to a member of an electrophotographic apparatus. The support 3 is formed in a cross-sectional “L” shape as a whole.

  The blade part 2 has a ridge line part 20 for contacting the mating member 9 and a first blade surface 21 and a second blade surface 22 that share the ridge line part 20 and are adjacent to each other. In FIG. 1, the symbol E indicates the ridge line direction of the blade part 2 (longitudinal direction of the blade part 2). Specifically, the first blade surface 21 is a plate surface along a direction V (short direction of the blade portion 2) perpendicular to the thickness direction T of the blade portion 2, and the blade portion 2 is attached to the mating member 9. It is set as the surface arrange | positioned so that it may face the other party member 9 side when making it contact | abut. On the other hand, the second blade surface 22 is specifically a tip surface (tip surface of the blade portion 2) along the thickness direction T of the blade portion 2, and the blade portion 2 is brought into contact with the mating member 9. It is set as the surface arrange | positioned so that the other party member 9 side may face in the case. In the blade portion 2, a part of the third blade surface 23, which is a plate surface opposite to the first blade surface 21, and a part of the plate surface of the plate-like part 31 in the support 3 are integrally joined. Has been.

In the cleaning blade 1, the birefringence of the first blade surface 21 and the birefringence of the second blade surface 22 in the blade portion 2 are both 1 × 10 ⁻⁵ or more.

<Experimental example>
Hereinafter, the cleaning blade will be described more specifically using experimental examples.

<Preparation of a polyurethane composition for forming a blade part>
Polybutylene adipate (PBA) degassed at 80 ° C. for 1 hour (Tosoh Corp., “Nipporan 4010”): 44 parts by mass, 4,4′-diphenylmethane diisocyanate (MDI) (Tosoh Corp., “Millionate” MT ”): 56 parts by mass were mixed and reacted at 80 ° C. for 3 hours in a nitrogen atmosphere to prepare a main agent solution containing a urethane prepolymer. In addition, NCO% (mass%) in the main agent liquid is 17.0%.

  Further, polybutylene adipate (PBA) (manufactured by Tosoh Corporation, “Nipporan 4010”): 87 parts by mass, 1,4-butanediol (manufactured by Mitsubishi Chemical Corporation) and trimethylolpropane (manufactured by Guangei Perstorp) in a weight ratio Low molecular weight polyol mixed at 6: 4: 13 parts by mass and triethylenediamine as a catalyst (manufactured by Tosoh Corporation): 0.02 part by mass in a nitrogen atmosphere at 80 ° C. for 1 hour. Thus, a curing agent liquid (1) having a hydroxyl value (OHV) of 212 (KOHmg / g) was prepared. Moreover, the hardening | curing agent liquid (2) whose hydroxyl value is 164 (KOHmg / g) was prepared by setting it as the above but polybutylene adipate: 91 mass part and low molecular weight polyol: 9 mass part. Similarly, the hardening | curing agent liquid (3) whose hydroxyl value is 259 (KOHmg / g) was prepared by setting it as polybutylene adipate: 83 mass part and low molecular weight polyol: 17 mass part.

  Next, as shown in Table 1, the prepared main agent solution, a predetermined curing agent solution, and a predetermined ionic conductive agent as required, with respect to 100 parts by mass of the main agent solution, a predetermined type of curing agent. When the liquid was blended with a predetermined part by mass and an ionic conductive agent, it was blended so as to have the content shown in Table 1, and mixed in a vacuum atmosphere at 60 ° C. for 3 minutes to sufficiently degas. Thereby, each polyurethane composition was prepared.

In addition, the following were used for the ionic conductive agent.
・ Ionic conductive agent (1)
Cationic species: K ⁺ , anionic species: CF ₃ SO ₂ C ₄ F ₉ SO ₂ N ⁻ (“EF-N142”, manufactured by Mitsubishi Materials Electronics Chemical Co., Ltd.)
・ Ionic conductive agent (2)
Cationic species: K ⁺ , anionic species: (CF ₃ SO ₂ ) ₂ N ⁻ (Mitsubishi Materials Electronics Chemicals, “EF-N112”)
・ Ionic conductive agent (3)
Cationic species: K ⁺ , anionic species: C ₂₈ H ₂₀ BO ₆ ⁻ (Nippon Carlit Co., “LR-147”)

<Preparation of cleaning blades for Sample 1 to Sample 9, Sample 3C, Sample 4C>
A mold composed of an upper mold and a lower mold was prepared. In the mold, the upper mold and the lower mold are brought close to each other and clamped to form a cavity having a size corresponding to one blade portion having a substantially long plate shape. One accommodation part is provided in the cavity. A plate-like portion of a conductive support made of a long metal plate (plate thickness: 2 mm) bent into an L-shaped cross section can be arranged in the housing portion. The upper mold and the lower mold are adjustable in temperature. In this example, the polyurethane composition is cast into the cavity in the same direction as the longitudinal direction of the blade part to be molded.

  Next, an adhesive was applied to one plate surface of the plate-like portion of the support. As the adhesive, an epoxy adhesive (manufactured by Toagosei Co., Ltd., “Aronmighty AS-60”) was used. For samples 5 to 7, carbon black (“# 3030B” manufactured by Mitsubishi Chemical Corporation) was added to the adhesive as an electronic conductive agent.

  Subsequently, the support body to which the adhesive was applied was set in the housing portion of the mold and clamped. Thereafter, as shown in Table 1, a predetermined polyurethane composition is cast at a predetermined casting speed in the cavity in the same direction as the longitudinal direction of the blade part to be molded, and a predetermined upper mold temperature and lower mold temperature are set. And the polyurethane composition was hardened by heating by predetermined heating time. Thereafter, the molded body was taken out from the mold. Thus, cleaning blade samples of Samples 1 to 9, Sample 3C, and Sample 4C having a blade portion (thickness 2 mm) made of polyurethane having a plate-like shape were formed.

<Preparation of cleaning blade for sample 1C>
A predetermined polyurethane composition (using the curing agent liquid (1)) is poured into a mold in a centrifugal molding machine, heated at 140 ° C. for 20 minutes, and cooled to form a 2 mm thick polyurethane cylindrical sheet. did. Next, by cutting the sheet body, a polyurethane blade portion (thickness 2 mm) having a plate-like shape was formed. Next, this blade part was adhered to the same support as described above, thereby forming a cleaning blade of Sample 1C.

<Preparation of cleaning blade for sample 2C>
A cleaning blade of sample 2C was formed in the same manner as the preparation of the cleaning blade of sample 1 except that the mold was filled with the polyurethane composition so that the cavities were gradually filled.

<Measurement of birefringence of blade part>
For the cleaning blade of each sample, the birefringence of the blade portion was measured according to the measurement method described above.

<Measurement of tan δ peak temperature of blade part>
For the cleaning blade of each sample, the tan δ peak temperature of the blade portion was measured according to the measurement method described above.

<Bake resistance>
The ridge line portion of the blade portion of the manufactured cleaning blade was assembled so as to be in sliding contact with the photosensitive drum of a digital copying machine (“Imagio MPC4000” manufactured by Ricoh Company). Then, 100,000 sheets of character chart images (A4 size) with an image area ratio of 5% were output in an environment of 23 ° C. × 55% RH. After the endurance output, the cleaning blade was taken out and examined for the presence of burrs at the ridgeline.

  After the endurance, the case where there was no chipping on the ridge line portion was designated as “A”, and after the endurance, the case where there was a chipping on the ridge line portion was indicated as “C”.

<Toner stain resistance>
After the endurance, a commercially available tape (Okamoto, “No. 300”) was applied to the surface of the charging roll of the digital copying machine, and then the tape was peeled off. Then, the area ratio of the toner stain portion with respect to the tape application area was determined. The case where there was almost no toner stain was designated as “A” as having excellent toner stain resistance. The case where the toner stain was observed within the allowable range where the area ratio of the toner stain portion was 20% or less was designated as “B” as having good toner stain resistance. A case where the area ratio of the toner stain portion was more than 20% was designated as “C” because the cleaning property was inferior.

  Table 1 summarizes the detailed configuration and evaluation results of the cleaning blades for each sample produced.

  According to Table 1, the following can be said. That is, in the cleaning blades of Samples 1C to 4C, the birefringence rates of the first blade surface and the second blade surface are outside the specified range. For this reason, the cleaning blades of Samples 1C to 4C were poor in anti-bake properties. Therefore, it can be said that the cleaning blades of the samples 1C to 4C are likely to be chipped at the ridge line portion while being used for a long time.

  This result is thought to be due to the following reasons. That is, for the cleaning blade of Sample 1C, the polyurethane sheet produced by the centrifugal molding method was cut into a blade portion, so that the crystal part of the polyurethane polymer constituting the blade portion was along the ridge line direction of the blade portion. It is thought that this is because the film was not oriented. Regarding the cleaning blade of Sample 2C, the polyurethane portion was formed by gradually filling the polyurethane composition, so that the crystalline part of the polyurethane polymer constituting the blade portion was not oriented along the ridge line direction of the blade portion. This is considered to be the cause. With regard to the cleaning blades of Sample 3C and Sample 4C, because the mold temperature and the casting speed of the polyurethane composition were not appropriate, the crystalline part of the polyurethane polymer constituting the blade portion was along the ridge line direction of the blade portion. It is thought that this is because the film was not oriented.

On the other hand, the cleaning blades of Samples 1 to 9 each have a birefringence of 1 × 10 ⁻⁵ or more on the first blade surface and the second blade surface. For this reason, it was confirmed that the cleaning blades of Samples 1 to 9 were more excellent in anti-scratch resistance than conventional. This is because the crystal part of the polyurethane polymer constituting the blade part is oriented along the direction of the ridge line part of the blade part, so that local unevenness of the crystal orientation of the polyurethane polymer in the blade part is reduced, and the entire blade part is broken. This is thought to be because it became difficult to occur.

  Further, when the cleaning blades of Samples 1 to 9 are compared, the following can be understood. That is, in the cleaning blades of Samples 1 to 6, the birefringences of the first blade surface and the second blade surface are both in the specified range, and the tan δ peak temperature of the blade portion is in the range of −8 ° C. It is in. For this reason, the cleaning blades of Samples 1 to 6 can prevent the toner from slipping out of the ridge line portion during the long-term use, and can prevent the toner from slipping out of the crushed portion, and can also ensure the followability of the blade portion and prevent the blade portion from jumping up. It can be seen that the effect makes it easy to form an image with little toner stain even during long-term use.

  As mentioned above, although the Example of this invention and the experiment example were demonstrated in detail, this invention is not limited to the said Example and experiment example, A various change is possible within the range which does not impair the meaning of this invention. is there.

DESCRIPTION OF SYMBOLS 1 Cleaning blade 2 Blade part 20 Edge line part 21 1st blade surface 22 2nd blade surface 9 Counterpart member

Claims (3)

A cleaning blade used to remove residual toner remaining on the surface of a mating member in an electrophotographic apparatus,
It has a blade made of polyurethane that exhibits a plate-like shape,
The blade part has a ridge line part for contacting the counterpart member, and a first blade surface and a second blade surface that share the ridge line part and are adjacent to each other,
The cleaning blade, wherein the birefringence of the first blade surface and the second blade surface is 1 × 10 ⁻⁵ or more.   The cleaning blade according to claim 1, wherein the blade portion has a tan δ peak temperature of −8 ° C. or more and 8 ° C. or less.   The cleaning blade according to claim 1, wherein the blade portion contains a potassium salt.

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