JP2008139744A - Cleaning blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cleaning blade having good cleaning performance even to spherical toner. <P>SOLUTION: The cleaning blade comprising a polyurethane elastomer for removing residual toner by touch with a toner carrier satisfies (1) a 100% modulus of 4.0-6.0 MPa, (2) a breaking extension in a tensile test of ≤250%, (3) an impact elastic modulus at 25°C of 15-27% and (4) a hardness (IRHD) of 70-80°. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cleaning blade used in an image forming apparatus using an electrostatic transfer process such as an electrophotographic copying machine, a laser beam printer, and a facsimile machine.

  An electrophotographic copying machine and a laser beam printer perform copying by attaching toner onto an electrostatic latent image formed on a photosensitive drum and transferring the toner onto a copy sheet. As one of the methods for removing the toner remaining on the photosensitive drum after the copying, a cleaning blade composed of a blade portion made of polyurethane elastomer and a support fitting (holder) has been put into practical use.

  Conventionally, as a material used for the cleaning blade, a polyester urethane elastomer having excellent mechanical strength such as wear resistance and low creep property (permanent deformation due to contact stress), particularly a thermosetting urethane elastomer is used. Has been used. This polyester-based urethane elastomer is produced by a prepolymer method, a semi-one-shot method, a one-shot method or the like using a polyisocyanate, a polyol, a chain extender and a catalyst. For example, when manufacturing a cleaning blade by the prepolymer method, a prepolymer is prepared using polyisocyanate and polyol, a chain extender and a catalyst are added to the prepolymer, and then this is injected into a molding die. And then cured.

  In order for the cleaning blade to completely remove the residual toner, it is necessary that the contact of the blade member on the outer peripheral surface of the photosensitive drum is always kept constant. For this reason, methods are generally used in which the positional relationship between the cleaning blade and the photosensitive drum is regulated, or the support fitting is pressed with a spring. However, in recent years, with the improvement in image quality of electrophotographic copying machines and laser beam printers, spherical toner having a smaller particle size than the conventional one has come to be used. As a result, the toner is more likely to slip between the photosensitive drum and the cleaning blade as compared with the conventional case, and cleaning failure is likely to occur.

  In view of this, as a countermeasure for preventing poor cleaning of the spherical toner, for example, there is a method of increasing the linear pressure of the blade edge portion on the surface of the photosensitive drum. However, countermeasures based on a mere increase in linear pressure have technical problems such as the abrasion of the blade edge or the abrasion of the drum due to the contact of the cleaning blade is accelerated, or abnormal noise is generated due to chatter vibration of the blade.

In addition, methods (Patent Documents 1 and 2) have been proposed that aim to prevent the occurrence of these technical problems by using spherical toner and irregular toner mixed at a specific ratio. . However, even when such a method is used, since the spherical toner may pass through the gap between the irregular toner and advance to the blade edge portion, the cleaning defect for the spherical toner has not been sufficiently improved. There is no current situation.
JP 08-62893 A Japanese Patent Laid-Open No. 08-95286

  The present invention has been made in view of the above situation. That is, the present inventor has made various studies in order to obtain a cleaning blade having a good cleaning performance for spherical toner. As a result, it has been discovered that the cleaning performance for spherical toner is greatly influenced by the elasticity, mechanical strength and hardness of the cleaning blade. That is, (1) 100% modulus in the tensile test, (2) elongation at break, (3) rebound resilience at 25 ° C., and (4) hardness is set to a predetermined range, which is favorable for spherical toner. The inventors have found that the cleaning performance can be achieved and have reached the present invention.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a cleaning blade having good cleaning performance even for spherical toner, because the cleaning blade has specific characteristics.

In order to solve the above problems, the present invention is characterized by having the following configuration.
1. A cleaning blade containing a polyurethane elastomer for contacting a toner carrier to remove residual toner,
A cleaning blade characterized by satisfying the following conditions (1) to (4):
(1) 100% modulus is 4.0 MPa or more and 6.0 MPa or less (2) Elongation at break in tensile test is 250% or less (3) Rebound resilience at 25 ° C. is 15% or more and 27% or less (4) Hardness (IRHD) is 70 ° or more and 80 ° or less. A cleaning blade containing a polyurethane elastomer for contacting a toner carrier to remove residual toner,
The polyurethane elastomer contains the following materials (A) to (E), and the concentration of (A) polyisocyanate calculated by the following formula (I) is 1.08 mmol / g or more and 1.30 mmol / 2. The cleaning blade according to 1 above, wherein the cleaning blade is g or less.
(A) Polyisocyanate (B) Polyol having a number average molecular weight of 2000 or more and 4000 or less (C) Chain extender having a molecular weight of 200 or less (D) Polyol (E) curing catalyst having a number average molecular weight of more than 200 and less than 2000 (I) (A) Concentration of polyisocyanate (mmol / g)
= W _iso / (Mn _iso × W _all ) × 1000
(In the formula (I), W _iso is the charged amount of (A) polyisocyanate (g), Mn _iso is the number average molecular weight of (A) polyisocyanate, and W _all is the material of (A) to (E). Represents total mass (g)).

3. 3. The cleaning blade as described in 2 above, wherein the polyisocyanate (A) is 4,4′-diphenylmethane diisocyanate.
4). 4. The cleaning blade according to 2 or 3 above, wherein the (D) polyol is a polyhexylene adipate polyol having a number average molecular weight of 500 or more and 1500 or less.
5. 5. The cleaning blade according to any one of 2 to 4 above, wherein (E) the curing catalyst comprises potassium acetate and an amine compound having one hydroxyl group at the terminal.

  According to the present invention, it is possible to obtain a cleaning blade having good cleaning performance even for spherical toner.

(Cleaning blade)
FIG. 1 shows an example of a cleaning means provided with the cleaning blade of the present invention. In FIG. 1, the cleaning means is configured by attaching a cleaning blade 22 of the present invention to a metal holder (rigid plate-like body) 21. One end portion of the cleaning blade 22 constitutes an end ridge line portion 23, and the cleaning blade contacts the toner carrier via the end ridge line portion 23, and the end ridge line portion 23 causes the cleaning blade 22 to contact the toner carrier. Scrape and remove residual toner.

The cleaning blade of the present invention is a cleaning blade that satisfies the following conditions (1) to (4) and contains a polyurethane elastomer.
(1) 100% modulus is 4.0 MPa or more and 6.0 MPa or less (2) Elongation at break in tensile test is 250% or less (3) Rebound resilience at 25 ° C. is 15% or more and 27% or less (4) Hardness (IRHD) is 70 ° or more and 80 ° or less.
Hereinafter, the cleaning blade of the embodiment will be described in detail.

  In the cleaning blade of the present embodiment, (1) the 100% modulus is 4.0 MPa or more and 6.0 MPa or less. When the 100% modulus is less than 4.0 MPa, the linear pressure of the blade edge portion applied to the surface of the photosensitive drum is insufficient, and the toner slips and the cleaning failure is likely to occur. Further, since the blade edge is easily deformed, chipping is likely to occur. On the other hand, when the 100% modulus exceeds 6.0 MPa, the linear pressure of the blade edge applied to the surface of the photosensitive drum or the like (toner carrier) becomes high, and the blade edge or the photosensitive drum surface is likely to be worn. The 100% modulus is preferably 4.5 MPa or more and 5.5 MPa or less. When the 100% modulus is within these ranges, a cleaning blade having superior durability can be obtained.

  (2) The elongation at break in the tensile test needs to be 250% or less. When the elongation at break in the tensile test exceeds 250%, when the blade edge is chipped due to rubbing against the photosensitive drum, the chip tends to be large, which causes a cleaning failure. The elongation during the tensile test is preferably 230% or less. When the elongation at the time of the tensile test is within these ranges, it is possible to prevent the cleaning failure more effectively.

  (3) The rebound resilience at 25 ° C. is 15% or more and 27% or less. When the impact resilience is less than 15%, the movement of the blade edge becomes dull and sufficient cleaning performance cannot be obtained. On the other hand, when the rebound resilience exceeds 27%, the movement (vibration) of the blade edge becomes too large in the rubbing between the photosensitive drum and the blade edge, and the toner easily slips through. The rebound resilience at 25 ° C. is preferably 20% or more and 25% or less. When the rebound resilience at 25 ° C. is within these ranges, a more sufficient cleaning performance can be obtained.

  In the cleaning blade of this embodiment, (4) hardness (IRHD) is 70 ° or more and 80 ° or less. When the hardness is less than 70 ° (IRHD), the blade edge is soft and the toner easily slips through. On the other hand, if the hardness exceeds 80 ° (IRHD), the blade edge becomes too hard, and the photosensitive drum wears quickly. The hardness is preferably 72 ° or more and 76 ° or less. When the hardness is within these ranges, the durability and cleaning performance of the cleaning blade can be optimized.

  As described above, by controlling the total of (1) 100% modulus, (2) elongation at break, (3) rebound resilience and (4) hardness, good cleaning performance can be obtained even for spherical toner. Can be obtained.

Here, the polyurethane elastomer constituting the cleaning blade contains the following materials (A) to (E), and the concentration of (A) polyisocyanate calculated by the following formula (I) is 1.08 mmol / g. Above, it is preferable that it is 1.30 mmol / g or less.
(A) Polyisocyanate (B) Polyol having a number average molecular weight of 2000 or more and 4000 or less (C) Chain extender having a molecular weight of 200 or less (D) Polyol (E) for curing a polyol (E) having a number average molecular weight of more than 200 and less than 2000 Catalyst (I) (A) Concentration of polyisocyanate (mmol / g)
= W _iso / (Mn _iso × W _all ) × 1000
(In the formula (I), W _iso is the charged amount of (A) polyisocyanate (g), Mn _iso is the number average molecular weight of (A) polyisocyanate, and W _all is the material of (A) to (E). Represents total mass (g)).

  Here, when the concentration of the polyisocyanate (A) is less than 1.08 mmol / g, the amount of hard segments in the polyurethane elastomer is reduced and softened, so the above conditions (1) to (4) may not be satisfied. is there. On the other hand, when the polyisocyanate concentration exceeds (A) 1.30 mmol / g, the amount of hard segments in the polyurethane elastomer becomes too large and hard, so that the physical properties of the above conditions (1) to (4) are not satisfied. There is. For this reason, the concentration of (A) polyisocyanate is preferably 1.08 mmol / g or more and 1.30 mmol / g or less, more preferably 1.10 mmol / g or more and 1.20 mmol / g or less, More preferably, it is at least 11.11 mmol / g and not more than 1.16 mmol / g. (A) When the concentration of the polyisocyanate is within these ranges, the cleaning blade can have an appropriate hardness, and excellent cleaning performance can be achieved.

  (B) The number average molecular weight of the polyol is preferably 2000 or more and 4000 or less, and more preferably 2300 or more and 2700 or less. (B) When the number average molecular weight of the polyol is within these ranges, the cleaning blade can have excellent hardness and cleaning performance.

  (D) The polyol number average molecular weight is larger than 200 and preferably smaller than 2000, preferably 500 or more and 1500 or less. (D) When the number average molecular weight of the polyol is within these ranges, the cleaning blade can have excellent durability and cleaning performance.

  Further, the molecular weight of the (C) chain extender is preferably 200 or less, and more preferably 150 or less. The molecular weight of the chain extender has a great influence on the elasticity, mechanical strength and hardness of the cleaning blade. When the molecular weight is within these ranges, it is possible to effectively prevent toner slipping and cleaning blade wear. Can do.

  Moreover, in this embodiment, by using the material for polyurethane elastomers containing the materials (A) to (E), the flow pattern to the mold is good and the surface pattern caused by the shrinkage unevenness does not occur. For this reason, the production efficiency of the cleaning blade can be increased.

The preferable content of the polyurethane elastomer materials (A) to (E) in the polyurethane elastomer is described below.
(A) Polyisocyanate: 27% by mass or more and 32% by mass or less (B) Polyol: 50% by mass or more, 58% by mass or less (C) Chain extender: 3.4% by mass or more, 4.6% by mass or less ( D) Polyol: 10% by mass or more and 15% by mass or less (E) Curing catalyst: 0.01% by mass or more and 0.07% by mass or less.
Hereinafter, the materials (A) to (E) will be described in more detail.

(A) Polyisocyanate (A) The polyisocyanate is not particularly limited, and the following polyisocyanates can be used. For example, isophorone diisocyanate, 4,4′-dicyclohexyl diisocyanate, trimethylhexamethylene diisocyanate, tolylene diisocyanate, carbodiimide modified diisocyanate, polymethylene phenyl polyisocyanate, orthotoluidine diisocyanate, naphthalene diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, paraphenylene Examples include diisocyanate, lysine diisocyanate methyl ester, dimethyl diisocyanate, and 4,4′-diphenylmethane diisocyanate. These may be used alone or in combination of two or more. Of these, 4,4′-diphenylmethane diisocyanate is preferably used in terms of reactivity and safety.

(B) Polyol, (D) Polyol As (B) polyol and (D) polyol used together with the above (A) polyisocyanate, for example, polyethylene adipate polyol, polybutylene adipate polyol, polyhexylene adipate polyol, (polyethylene / polypropylene) ) Adipate polyols such as adipate polyol, (polyethylene / polybutylene) adipate polyol, and (polyethylene / polyneopentylene) adipate polyol. Moreover, polyether polyols such as polycaprolactone polyols obtained by ring-opening polymerization of caprolactone, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and the like can be mentioned. Polycarbonate diol may also be used. These can be used alone or in admixture of two or more.

  In addition, although (B) polyol and (D) polyol may use the same polyol or different polyol, the range of the number average molecular weight of these polyols differs. Among these, as the (D) polyol, a polyhexylene adipate polyol having a number average molecular weight of 500 or more and 1500 or less is preferable from the viewpoint of moldability and physical properties.

(C) Chain extender Examples of the chain extender (C) include 1,4-butanediol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, hexanediol, 1,4-cyclohexanediol, 1 , 4-cyclohexanedimethanol, xylylene glycol, triethylene glycol, trimethylolpropane, glycerin, pentaerythritol, sorbitol, 1,2,6-hexanetriol and the like having a number average molecular weight of 200 or less. . These may be used alone or in combination of two or more.

(E) Curing catalyst Examples of the curing catalyst include amine compounds such as tertiary amines and organometallic compounds. Tertiary amines include trialkylamines such as triethylamine, tetraalkyldiamines such as N, N, N ′, N′-tetramethyl-1,3-butanediamine, aminoalcohols such as dimethylethanolamine, and ethoxyl. Amines, ethoxylated diamines, ester amines such as bis (diethylethanolamine) adipate, cyclohexylamine derivatives such as triethyldiamine and N, N-dimethylcyclohexylamine, N-methyl formalin, N- (2-hydroxypropyl) And morpholine derivatives such as dimethylmorpholine, and piperazine derivatives such as N, N′-diethyl-2-methylpiperazine and N, N′-bis- (2-hydroxypropyl) -2-methylpiperazine.

Among them, an amine compound having one hydroxyl group at the terminal which is reactive and blooms after molding and does not affect other parts is preferable. As the amine compound, N, N, N′-trimethylaminopropylethanolamine is preferable.
Examples of the organometallic catalyst include tin octylate, dibutyltin dilaurate, lead octylate, lead naphthenate, and potassium acetate. Preferably, potassium acetate is used.

(Manufacturing method of cleaning blade)
The cleaning blade of this embodiment can be manufactured according to a conventional method using each of the materials (A) to (E). Specifically, it can be produced according to a prepolymer method, a semi one-shot method, or a one-shot method.

  In the present invention, a cleaning blade is produced, for example, as follows according to the prepolymer method. First, a cleaning blade mold is prepared. Next, a polyurethane elastomer prepolymer partially polymerized with polyol (preferably (A) polyisocyanate and (B) polyol), (D) polyol, (E) curing catalyst, and (C) chain extender are charged. Then, the mixture is stirred in a mixing chamber to obtain a liquid mixture. A cleaning blade can be manufactured by pouring this into the mold and reaction curing, then removing the cured product and cutting it into a predetermined dimension.

(Electrophotographic equipment)
A schematic view of an example of an electrophotographic apparatus incorporating the cleaning blade of the present invention is shown in FIG.
The electrophotographic apparatus includes a developing roller 4 having a photosensitive member 2, a charger 1 as a charging unit, a ROS (latent image writing device) 13 as an exposure unit, and four developing units 31 to 34 as developing units. Prepare. Further, the image forming apparatus includes an intermediate transfer belt 40 and a secondary transfer device 48 that are transfer units, a cleaner 50 that is a cleaning unit, a fixing unit 64, and paper supply / discharge systems 60 to 62 and 65.

  The developing device 31 includes a developing container 37a that stores a two-component developer of K (black), and a developing sleeve 35a provided in the developing container 37a. In addition, it has a regulating blade 36a for regulating the developer carried on the developing sleeve 35a and regulating the head height of the magnetic brush formed on the sleeve. The developing device 32 contains a Y (yellow) developer, the developing device 33 contains an M (magenta) developer, and the developing device 34 contains a C (cyan) developer. The configuration is the same as the developing device 31.

  The photoconductor cleaner 50 includes a cleaning blade 52 that contacts the surface of the photoconductor 2 and a cleaning container 51 that stores toner particles and the like removed by the cleaning blade. The photoreceptor 2 rotates in the direction of the arrow Da, and the surface thereof is uniformly charged by the charger 1 and then exposed and scanned by the laser beam L from the ROS 13 to form an electrostatic latent image. When forming a full-color image, electrostatic latent images corresponding to four color images of K (black), Y (yellow), M (magenta), and C (cyan) are sequentially formed. Only the electrostatic latent image corresponding to the (black) image is formed. The developing units 31 to 34 are transported to the developing position by the rotation of the developing roll 4 and convert the electrostatic latent image on the surface of the photoreceptor 2 that passes through the developing area B into a toner image.

  After the primary transfer, residual toner on the surface of the photoreceptor 2 is removed by the cleaning blade 52. The recording sheet S accommodated in the paper feed tray 60 is taken out by the pickup roll 61 at a predetermined timing and conveyed to the registration roll pair 62. The registration roll pair 62 conveys the recording sheet S to the secondary transfer area E in time with the primary transfer of the multiple toner image or the single color toner image moving to the secondary transfer area E. In the secondary transfer region E, the secondary transfer unit 48 electrostatically and collectively transfers the toner image on the intermediate transfer belt 40 onto the recording sheet S. The intermediate transfer belt 40 after the secondary transfer is cleaned by a belt cleaner 47, and residual toner on the belt is removed.

  The recording sheet S on which the toner image is secondarily transferred is conveyed to the fixing device 64 by the sheet conveying belt 63 and is heated and fixed by the fixing device 64. The recording sheet S on which the toner image is fixed is discharged to the recording sheet discharge tray 65.

In this electrophotographic apparatus, the cleaning blade of the present invention can be used as the cleaning blade 52. In this case, the photoreceptor 2 is a toner carrier.
In addition, the electrophotographic cleaning blade of the present invention can be used as a cleaning blade of an electrophotographic apparatus to which electrophotographic technology is applied such as a copying machine, a laser beam printer, an LR printer (LED printer), and an electrophotographic plate making system.

Next, examples and comparative examples of the present invention will be shown. The present invention is not limited only to these examples.
(Example 1)
(Adjustment of materials for polyurethane elastomer)
In the proportions shown in Table 1, 4,4′-diphenylmethane diisocyanate (MDI: (A) polyisocyanate) and polybutylene adipate polyol (PBA, number average molecular weight 2000: (B) polyol) were 120 ° C. in a nitrogen atmosphere at 80 ° C. It was made to react for minutes and the prepolymer was obtained. Further, 1,4-butanediol (1,4-BD: (C) chain extender), trimethylolpropane (TMP: (C) chain extender), polyhexylene adipate polyol at the ratio shown in Table 1 (PHA, number average molecular weight 1000: (D) polyol) and (E) a curing catalyst were mixed to obtain a curing agent.
The prepolymer and the curing agent were mixed when molding to prepare a polyurethane elastomer material.

(Forming a cleaning blade)
In advance, a holder was prepared as a support member, and an adhesive was applied to one end surface of the holder. A cleaning blade forming die composed of an upper die and a lower die was placed in a state where one end portion of the holder coated with an adhesive protruded into the cavity. Next, the polyurethane elastomer material was injected into the cavity. This was reacted and cured at a heating temperature of 130 ° C., and then the cured product was removed from the mold and cut into a predetermined size to prepare a cleaning blade.

  The cleaning blade thus prepared was subjected to calculation of polyisocyanate concentration, 100% modulus, elongation at break, rebound resilience, hardness (IRHD), and image evaluation as described below.

[Polyisocyanate concentration]
The polyisocyanate concentration of the obtained cleaning blade was calculated by the following formula (I). The results are shown in Tables 1 and 2.
(I) (A) Polyisocyanate concentration (mmol / g) = W _iso / (Mn _iso × W _all ) × 1000
(However, in the above formula (I), W _iso is the charge amount (g) of (A) polyisocyanate, Mn _iso is the number average molecular weight of (A) polyisocyanate, and W _all is the material of (A) to (E). (A) The amount of polyisocyanate charged (g) is the amount of (A) polyisocyanate (g) actually added to the polyurethane elastomer material for the production of the cleaning blade. In addition, the number average molecular weight is obtained by preparing a calibration curve between the peak count number and the number average molecular weight of the monodisperse polystyrene by GPC using monodisperse polystyrene for gel permeation chromatography (GPC). The measurement conditions of the sample are as follows: Column: G3000PWXL × 2 (manufactured by Tosoh Corporation), elution solvent: 20 mM phosphate buffer, detector: Differential refractometer, flow rate: 0.5 mL / min, sample solution amount: 10 [mu] L, and column temperature: was 45 ° C.).
[(1) Measurement of 100% modulus]
Measurement was performed based on JIS K 6251 using a tensile tester (Unitron TS-3013) manufactured by Ueshima Seisakusho on the cleaning blade thus prepared. The results are shown in Table 3.
[(2) Measurement of elongation at break in tensile test]
Measurement was performed based on JIS K 6251 using a tensile tester (Unitron TS-3013) manufactured by Ueshima Seisakusho on the cleaning blade thus prepared. The results are shown in Table 3.

[(3) Measurement of impact resilience]
Measurement was performed at 25 ° C. based on JIS K 6255 using the Rupke-type rebound resilience test apparatus manufactured by Ueshima Seisakusho for the produced cleaning blade. The results are shown in Table 3.
[(4) Hardness (IRHD)]
Measurement was performed based on JIS K 6253 using a hardness meter manufactured by HW WALLACE on the produced cleaning blade. The results are shown in Table 3.

[Image evaluation]
The prepared cleaning blade was incorporated into LASER SHOT LBP-2510, a cleaning property test was performed, and the presence or absence of cleaning failure was observed. Here, “Good” indicates that the cleaning property is good (no occurrence of cleaning failure), “Good” indicates that the cleaning failure is mild, and “X” indicates that the cleaning failure is severe. The results are shown in Table 3.

(Example 2)
(B) A cleaning blade was prepared and evaluated in the same manner as in Example 1 except that polybutylene adipate polyol having a number average molecular weight of 2000 was used as the polyol and the prepolymer and the curing agent were adjusted according to the formulation shown in Table 1. went. The results are shown in Table 3.

(Example 3)
(B) A cleaning blade was prepared and evaluated in the same manner as in Example 1 except that polyhexylene adipate polyol having a number average molecular weight of 2600 was used as the polyol, and the prepolymer and the curing agent were adjusted according to the formulation shown in Table 1. Went. The results are shown in Table 3.

(Comparative Example 1)
(B) Polybutylene adipate polyol having a number average molecular weight of 2000 is used as the polyol, and the curing agent has a number average molecular weight smaller than (B) the number average molecular weight of the polyol (C) and larger than the molecular weight of the chain extender (D) No polyol was added. A cleaning blade was prepared and evaluated in the same manner as in Example 1 except that the prepolymer and the curing agent were adjusted according to the formulation shown in Table 2. The results are shown in Table 4.

(Comparative Example 2)
(B) Polybutylene adipate polyol having a number average molecular weight of 2000 is used as the polyol, and (B) the number average molecular weight is smaller than the number average molecular weight of the polyol (C) and larger than the molecular weight of the chain extender. Polybutylene adipate with a molecular weight of 1000 was used. A cleaning blade was prepared and evaluated in the same manner as in Example 1 except that the prepolymer and the curing agent were adjusted according to the formulation shown in Table 2.

  In addition, the number in the column of 1, 4-BD, TMP in Table 1 and Table 2 represents (mass part). The number in the (E) curing catalyst column represents the content (mass%) in the cured body (cleaning blade).

Moreover, the following were used as each said constituent material.
Polyisocyanate (MDI): Millionate MT (trade name), polybutylene adipate polyol (PBA-2000) manufactured by Nippon Polyurethane Industry Co., Ltd. (PBA-1000): Nippon Run 4009 (trade name)
Polyhexylene adipate polyol (PHA-2000): Nipponran 4073 (trade name)
1,4-butanediol (1,4-BD: molecular weight 90.1): trimethylolpropane manufactured by Mitsubishi Chemical Corporation (TMP: molecular weight 134): curing catalyst (amine catalyst manufactured by Mitsubishi Gas Chemical Company, Inc.) ): POLYCAT 17 (trade name), Tosoh Co., Ltd. curing catalyst (potassium acetate): P15 (trade name), manufactured by Air Products Japan

  As can be seen from Tables 3 and 4, in Examples 1 to 3, the image evaluation is “◯”, indicating that no cleaning failure occurs and good cleaning performance is exhibited. On the other hand, Comparative Example 1 does not contain (D) polyol, and the 100% modulus is 3.7 MPa, which is outside the scope of the present invention. Moreover, in the comparative example 2, the density | concentration of (A) polyisocyanate is 1.07 (mmol / g) and the impact resilience rate is 28%, and it is outside the scope of the present invention. For this reason, in Comparative Examples 1 and 2, the image evaluation is “Δ” and “X”, respectively, and it can be seen that a cleaning failure has occurred.

It is a schematic diagram explaining an example of the cleaning means provided with the cleaning blade of this invention. It is the schematic showing an example of the electrophotographic apparatus incorporating the cleaning blade of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Charger 2 Photoconductor 3 Pre-exposure device 4 Developing roll 10 Original plate glass 11 Light source 12 CCD
13 Latent image writing device (ROS)
21 Holder 22 Cleaning blade 23 End ridgeline portion 30 Developing roll rotating shafts 31 to 34 Developing devices 35a to d Developing sleeves 36a to d Restricting blades 37a to d Developing container 40 Intermediate transfer belt 41 Position sensor 42 Primary transfer roll 43 Tension roll 44 Secondary transfer backup roll 45 Belt drive rolls 46, 47 Idler roll 48 Secondary transfer unit 49 Belt cleaner 50 Photoconductor cleaner 51 Cleaning container 52 Cleaning blade 60 Paper feed tray 61 Pickup roll 62 Registration roll pair 63 Sheet transport belts 64a-b Fixing device 65 Recording sheet discharge tray A Latent image writing position B Development area D Primary transfer area Da Rotating direction E of photoconductor Secondary transfer area G Laser beam L1 from original L ROS Length L2 of the hardened layer in the free length direction Cure The thickness of the cleaning blade in the thickness direction of the length S recording sheet T hardened layer itself

Claims (5)

A cleaning blade containing a polyurethane elastomer for contacting a toner carrier to remove residual toner,
A cleaning blade characterized by satisfying the following conditions (1) to (4):
(1) 100% modulus is 4.0 MPa or more and 6.0 MPa or less (2) Elongation at break in tensile test is 250% or less (3) Rebound resilience at 25 ° C. is 15% or more and 27% or less (4) Hardness (IRHD) is 70 ° or more and 80 ° or less A cleaning blade containing a polyurethane elastomer for contacting a toner carrier to remove residual toner,
The polyurethane elastomer contains the following materials (A) to (E), and the concentration of (A) polyisocyanate calculated by the following formula (I) is 1.08 mmol / g or more and 1.30 mmol / The cleaning blade according to claim 1, wherein the cleaning blade is g or less.
(A) Polyisocyanate (B) Polyol having a number average molecular weight of 2000 or more and 4000 or less (C) Chain extender having a molecular weight of 200 or less (D) Polyol (E) curing catalyst having a number average molecular weight of more than 200 and less than 2000 (I) (A) Concentration of polyisocyanate (mmol / g)
= W _iso / (Mn _iso × W _all ) × 1000
(In the formula (I), W _iso is the charged amount of (A) polyisocyanate (g), Mn _iso is the number average molecular weight of (A) polyisocyanate, and W _all is the material of (A) to (E). Represents total mass (g)).   The cleaning blade according to claim 2, wherein the (A) polyisocyanate is 4,4′-diphenylmethane diisocyanate.   The cleaning blade according to claim 2 or 3, wherein the (D) polyol is a polyhexylene adipate polyol having a number average molecular weight of 500 or more and 1500 or less.   The cleaning blade according to any one of claims 2 to 4, wherein (E) the curing catalyst includes potassium acetate and an amine compound having one hydroxyl group at a terminal.

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