JPS5999473A - Electrophotographic copying machine - Google Patents

Abstract

PURPOSE:To display excellent cleaning functions even at low temperature and to form an excellent copy picture by providing a cleaning blade made of specific urethane rubber. CONSTITUTION:An electrophotographic copying machine is equipped with a photosensitive body and the cleaning blade which cleans the surface of the photosensitive body by rubbing. The cleaning blade uses polyurethane rubber obtained by reacting polyisocyanate (e.g. hexamethylene diisocyanate) with polylactone ester [obtained by adding 1mol polymerization iniating agent (e.g. ethylene glycol) to a 2-35mol <=C5 lactone compound (shown by formula I or II) of the same or different kind incorporating a <=lactone ester compound and performing ring opening addition polymerization to 1,000-4,000 mean molecular weight] and then cured. Then, excellent cleaning functions are displayed even at low temperature and excellent copy pictures are formed.

Description

[Detailed description of the invention] The present invention relates to an electrophotographic copying machine.

In general, electrophotographic copying machines, especially electrophotographic copying machines that use plain paper as recording paper, develop the latent image formed on the photoreceptor with toner and transfer the toner image to the recording paper. Since the photoreceptor is used repeatedly, it is therefore necessary to clean the photoreceptor as the final step of each electrophotographic process to remove any residual toner deposited on the photoreceptor. An example of such a cleaning method is Cleani/Gup V-, which is made of an elastic material.
Are there any known blade cleaners that bring the blade into contact with the photoreceptor and rub it against the photoreceptor? This method is advantageous in that the configuration is very simple.

Conventionally, urethane rubber, silicone rubber, fluororubber, chlorograne rubber, butadiene rubber, etc. are known as grade materials used in this plastic cleaning system. It is extremely useful in terms of its mechanical properties, especially its abrasion resistance, compared to other materials.

Conventionally, for cleaning blades, for example, urethane rubber obtained by reacting polyethylene adipate ester, polyoxygloping glycol, caprolact/ester, etc. with polyincyanate can be used as a material, for example, as disclosed in JP-A-54 -1048
It is described in Publication No. 40. However, not all substances belonging to this group of substances are suitable for use as a cleaning blade, regardless of the structure of C, molecular weight, etc. Currently, 8 uses polyethylene adipate ester as a raw material, 4゜4'-dimethine/diisocyanate, 1,5-naphthylene diisocyanate, and other polyisocyanate raw materials, and uses 1,4-butanediol, etc. as a curing agent for these polyisocyanates. Reactively cured by the action of glycol is used, but
In this cleaning grade 8, the characteristics change greatly due to changes in ambient temperature, for example at temperatures below 10 degrees Celsius. However, there is a drawback that the desired cleaning effect is not always achieved satisfactorily.

The present invention has been made based on these circumstances, and its purpose is particularly to maintain cleanliness/cleanliness even in low-temperature environments.
To provide an electrophotographic copying machine in which a good copying blade can be used and a leaning function 7 can be utilized to form a good copy image.

The purpose of this is to clean the photoconductor and the cleaning blade that rubs against the surface of the photoconductor. In the electrophotographic copying machine, the cleaning blade is made of a urethane rubber material obtained by curing a polylactone ester containing a lactone ester component having 5 or less carbon atoms with a polyisocyanate. This is achieved by an electrophotographic copying machine characterized by the following.

The present invention will be explained in detail below with reference to the drawings.

In accordance with the present invention, as shown in FIG. 1, a photosensitive drum IIY is formed by forming a conductive sensitive layer made of a vapor-deposited film or the like on the outer circumferential surface of a base drum made of aluminum, for example. Set up to rotate.

In the outer peripheral area of the photosensitive drum 11, a photosensitive layer t? #Charging device 12 for electrifying, original light exposure/lighting device 18 for forming an electrostatic charge image, and developing device 1 for developing the electrostatic charge image
4 are arranged in this order in the rotational direction of the photoreceptor drums 1'' and 1'', and the transfer paper fed along the transfer path P by the developing device 14 and the C1 transfer paper feed roller 15 is subjected to development. A transfer electrode 16 for electrostatically transferring the formed toner particles and a separation electrode 17 for separating the photoreceptor drum 11 from the transfer paper are provided in this order.
An exposure mechanism 18 for erasing charges is provided along the rotation direction of 1,
In the area following this, the cleaning blade 19 is moved by the holder zO so that its leading edge part touches the photosensitive drum 1.
1 so as to face each other with a pressing force of, for example, 15 to 25 g weight 4, and a polylactone ester containing a lactone ester component having 5 or less carbon atoms is used as a material of 17-ning grade 19. An electrophotographic copying machine is constructed using urethane rubber obtained by reaction-curing with polyisocyanate. zl is a collection container for toner scraped off by the cleaning blade 19.

The present invention is characterized in that the cleaning blade 19 is made of urethane rubber obtained from a specific polylactone ester, and the electrophotographic copying machine may have any other configuration.

In the present invention, as described above, since the cleaning blade 19 is made of a specific urethane rubber,
The cleaning blade has good physical properties '4! : It has excellent physical properties, especially its stability at low temperatures. Therefore, it is good and stable even in a low-temperature environment, and a leaning effect can be obtained to form a good copied image.

The reason why such an excellent effect is obtained is not necessarily clear, but the inclusion of a lactone ring component allows the urethane rubber to have good physical properties, and the fact that the lactone has 5 or less carbon atoms. Well, compared to the case where the polylactone ester that forms the urethane rubber is composed of a lactone ester component with more than 5 carbon atoms, the number of ester components will be larger for the same molecular weight. The intramolecular bonding force of the ester group of the ester component is effectively exerted, and as a result, the resulting urethane rubber has good physical properties and does not become brittle and harden especially at low temperatures. It is presumed that this is because it is retained.

The urethane rubber that is used as the material for the cleaning blade in the present invention has favorable characteristics such as a relatively low proportion of ester components consisting of lactones having 5 or less carbon atoms in the polylactone ester that is the raw material for the component. It is preferable to use a polylactone ester containing at least 80% by weight.

The polylactone ester obtained from the ester of lactone having 5 or less carbon atoms, which is the raw material for the urethane rubber that is the material of the cleaning play P, has an average molecular weight of 1.
It is preferably in the range of 000 to 4000.

Here, the method for measuring the average molecular weight is to add an acetylating reagent consisting of acetic anhydride and pyricine to the polylactone ester,
Acetylation is carried out at a specified reaction temperature and for a certain period of time, and the terminal OH group is quantified based on the amount of potassium hydroxide required to neutralize the acetic acid produced, and the number average molecular weight is measured.

Furthermore, in practice, the above polylactone ester is obtained as a mixture of various components with different bonding states, so it is not necessarily appropriate to define it by a specific structural formula. ), then
It can be thought of as follows.

General formula [I] HO → q "几 → almost 0) i In the formula, Xi and X2 are cleavage residues of a lactone ring having 5 or less carbon atoms, and may be the same or different, m ,
The sum of n is in a range of 2 to 85, and m:n is 1=8 to 8:1. R is a linking group for Xi and Xz and is a divalent organic group having about 800 or less carbon atoms. Also, the general formula CI
) (based on the above measurement method)
(A-molecular weight) is preferably 1,000 to 4,000, and the content of the lactone ester component (Xl+X2) is preferably 80% by weight or more. 1 Polylactone ester ya- as shown in the above general formula CI)
For production, 1 mole of polymerization initiator is added to 2 to 3.5 moles of the same or different lactone compound having 5 or less carbon atoms, and ring-opening addition is carried out at a temperature of 150 to 300C. Polymerized and average molecular weight 1000-4000
A polylactone ester is obtained. As the polymerization initiator, an organic compound having at least two active hydrogen groups, such as -0) one group, -NH2 group, or -8H group, is used.

The lactone compound for forming the urolactone ring cleavage residue in the general formula CI) is an 8- to 6-membered rough =581-i) CH2-c=6 HaU (α-va-rolactone) Examples of the polymerization initiator for forming the linking group R in 〇) include the following compounds.

Cl-1) Water CI-Z) HOCH2CH20H (ethylene glycol) [I-8] f-10CH2CH20CH
2CH20H (zoethylene glycol) (I-4) HOCH2CH2CH2CH20H
(Butanediol) CI-5]CH3 Cl-6) CH20HCH3-GHz
-C-CHz OH CH2O,H [:I-7] HO-(CH2CHzO←CH2CH
20H (n is 1 to 150) (Polyethylene glycol) CI-8) C(CH20H)4 (Pentaerythritol) (Phenethyl alcohol) CI-10] HzNCkhCH2NH2 (x Chile:
y Schiff i:y) CI-12) HzN-+CHzCH
zNH)-CH2CHzNHz (n is 1 to 100) (I-18) C(CH2NH2).

Cl-14) H8CHzCHz8H (1,2-ethanedithiol) (I-15) HOCHzCHz
NH2 (ethanolamine) [l-16]no-(CH
2NH2ci(2ci(2-0-)-H(n is 1-80
) (Polytetramethylene glycol) The above polylactone ester reacts with polyisocyanate in the presence of a curing agent to form urethane, which is the material of the cleaning blade in the present invention! As the polyisocyanate, for example, the following can be mentioned as suitable polyisocyanates.

CB-1) Hexamethylene diisocyanate 0CN
(CH2)60ON Commercial product = "Desmodur H" Commercial product manufactured by West German Bayer AG - "Desmodur N" Manufactured by West German Bayer AG CB-8) Metaphenylene zoisocyanate +-NG
I-lylene diisocyanate GO Commercial product = "Desmodur T" West German Bayer Co., Ltd. "Hyren'l'MJ Dupont [B-5] 2.4-Tolylene diisocyanate dimer Commercial product: [Desmodur TTJ manufactured by West German Bayer AG 3-6] Toluylene isocyanate and r-rimethyl
[:B-8] Commercial product of reaction product with rollpropane = "Desmodur L" Commercial product manufactured by Bayer AG, West Germany: "Coronate L" Manufactured by Nippon Polyurethane Kogyo Co., Ltd. 3-7) 8x8'-S) fL'7 Phoenix 4.
4'-[B-1g] Commercial product: "Hiren H"Diphenylmethane-4,4'-zoisocyanate-1 manufactured by DuPont
・Commercial product: [Mirione 1-MTJ 3.8'-dimethyl-diphenylmethane-4,4'-diisocyanate manufactured by Nippon Polyurethane Kogyo Co., Ltd. Commercial product = [Hiren DMMJ Triphenylmethane-triisocyanate NGO manufactured by DuPont Co., Ltd.
f: Rimethylene phenyl isocyanate-1, commercial product: [Millionate MR4, manufactured by Nippon Polyurethane Kogyo Co., Ltd. (B-12) Naphthalene-1,5-diisocyanate CO, commercial product = "Desmodur 15" ” (B-113) manufactured by Bayer AG, West Germany Zoshi Chlohexyl Methane Zoisocyanate manufactured by Allied Chemical Company Specific examples of the curing agent include the following.

) HO(CH2)40H (1,4-butanediol)(z,8-butanediol) (C-8) CH20HC2H5 -C
-CH20H CH20H (1,1.1-trimethylolzolopane) (C-4)
. .

(3,8'-cyclo4,4'-diaminodiphenylmethane) (C-5) N(CHa-CHOH)3-H3 (triisozolopanolamine) (C-6) HOCHzCHzOH (ethylene glycol) (4,4 '-diaminodiphenylmethane) (hydroquinone-bis(β-hydroxyethyl)ether) To manufacture a cleaning blade made of urethane rubber using the above polylactone ester, polyisocyanate, and curing agent, the following steps are performed. is suitable. That is, the dehydrated polylactone ester and polyisocyanate are mixed and heated at a temperature of 70 to 150 tll'.
A urethane sol polymer is prepared by reacting for 10 to 120 minutes, and the number of moles of incyanate groups due to the polyisocyanate and the number of moles of hydroxyl groups and/or amino groups due to the polyester and curing agent are determined for this urethane sol polymer. A liquid rubber composition is prepared by adding a curing agent in such a proportion that the ratio of the curing agent is 1.00 to 1.80, and this rubber composition is poured into a centrifugal casting machine kept at a temperature of, for example, about 140111'. Figure 2 shows an example of a centrifugal casting machine.
82 is a heating fluid flow path for heating the heating chamber 81; 38 is a heat insulating material layer; 84 is an opening/closing door; 35 is a cylindrical rotor; 86 is a drive shaft; 87 is a motor; The material is injected into the rotor 85 which is rotating at high speed, and due to the centrifugal force caused by the rotation, it is spread to a uniform thickness on the casting surface formed by the inner peripheral surface of the rotor 85, forming a cylindrical film-like material 88 (
Indicated by a chain line. ) is formed. This film-like body 88 is solidified as crosslinking by the curing agent progresses, and the thus formed solidified urethane rubber layer is peeled off from the casting surface, and then heat-treated and aged for several days to form a rubber plate for a blade. In addition to the above centrifugal casting method, in which the cleaning blade is manufactured by cutting the male plate according to the specifications of the planned electrophotographic copying machine, there is also a method in which, for example, it is injected into a mold in the shape of the cleaning blade and solidified. , or a method of pressure molding using such a mold, etc. 1) Any of these methods can advantageously produce a cleaning blade made of urethane material.

The above-mentioned urethane rubber may contain an anti-aging agent such as Mono-Ruki Diimi-P.

The present invention will be specifically explained below using examples, but the embodiments of the present invention are not limited to these examples.

EXAMPLE According to Table 1, lactone and a polymerization initiator were measured and mixed, and addition polymerized at a temperature of 150 to 850 C for about 30 to 180 minutes to synthesize polylactone esters PIJI to PLEIO having a total of 101i.

Table 1 PLE: Polylactone ester Lactone content: Content ratio of lactone ester component in PLE Average molecular weight: Average molecular weight of PLE PPG: &! 7 Zorobylene glycol To these 10 types of polylactone esters and polyethylene azobate esters, polyisocyanate was added according to the results shown in Table 2, and 1
The reaction was allowed to proceed for 00 minutes to synthesize a d
The DEM composition, which was reacted at C for 2 minutes and was still in a liquid state, was injected into the rotor of the centrifugal casting machine shown in Fig. 2, which was maintained at a temperature of around 14OC, and the rotor was rotated at about 1000 revolutions/minute. The solidified rubber 1- was formed by continuing to rotate for 20 to 11 minutes, which was peeled off, heat treated in a heating furnace at a temperature of about 140C for 180 minutes, and further aged at room temperature for 6 to 8 days. A total of 11 kinds of urethane rubber plates U1 to IJR11 having an inner diameter of 2,041,111 mm were obtained. The hardness of these urethane rubber plates according to the JI8 6801A scale was within a practically useful range of 65 to 76 degrees.

Table 2 Proportions represent the number of parts per 100 parts of ester UR: Urethane rubber plate MDI: Diphenylmethane-4,4'-diincyanate TDI: ) Lylene diincyanate PEAkJ: Polyethylene azobate ester 1.41
13: 1.4 butanezoyl MOCA: 8.3'-fuchloro-4'-diaminodiphenylmethane When the thickness distribution of these urethane rubber plates was investigated,
All errors had an accuracy of ±15 μm. These urethane rubber plates thus obtained were transferred to an electrophotographic copying machine [U
-Bix 8000J (Konishi Roku Photo Industry Co., Ltd. JR) was cut according to the specifications to obtain a total of 11 types of cleaning blades CBl to CB11.

The above-mentioned cleaning blades CBI to CB are used as cleaning grade 19 in the configuration shown in FIG.
11 to construct an electrophotographic copying machine, and
Continuous copying was performed under various environmental conditions shown in the table, and the number of copies until staining due to poor cleaning occurred was determined. The cleaning blade 19 is held by the holder 20 so that the angle between the tip contacting part and the surface of the photoreceptor drum 11 is 160 degrees with respect to the upstream surface, and the pressing force F is 25 g/crn. I forced it. The soot fruits are also shown in Table 8. Note that r40000J has 4 copies.
This indicates that no cleaning failure occurred even when the value reached 0000.

Table 8 As is clear from the above results, the cleaning grade was prepared by reacting a polylactone ester containing a lactone ester component having 5 or less carbon atoms with a polyisocyanate to obtain a urethane rubber material. According to the electrophotographic copying machine of the present invention, cleaning can be performed satisfactorily 5,000 times, which is necessary for practical use, especially at low temperatures, and especially when the electrophotographic copying machine contains 80% by weight or more of a lactone ester component having 5 or less carbon atoms, When a lactone ester or a polylactone ester having an average molecular weight of 1,000 to 4,000 is used, excellent copied images can be formed many times even at low temperatures.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram of an example of the configuration of an electrophotographic copying machine, and FIG. 2 is an explanatory sectional view of a centrifugal casting machine for manufacturing cleaning blades. 11... Photosensitive drum 1z... Charging device 18.
...Original light image exposure mechanism 14...Developer 15...Feeding roller P...Passage 16...Transfer electrode
17...Separation electrode 18...Exposure mechanism for charge erasure 19...Cleaning blade 20...Holder 21...Toner collection container 81...Heating chamber 3z...Heating fluid channel 8
8...Insulating material layer 84...Opening/closing door 85...
Cylindrical rotor 86... Drive shaft 87... Motor father Koshiroku Photo Industry Co., Ltd., 2970 Ishikawa-cho, Hachioji City. Applicant: Hokushin Kogyo Co., Ltd. 2-3-6 Shitte, Tsurumi-ku, Yokohama City, 587-

Claims (1)

[Scope of Claims] l) An electrophotographic copying machine comprising a photoconductor and a cleaning blade that cleans the surface of the photoconductor by rubbing against it; An electrophotographic copying machine characterized in that it is made of a urethane rubber material obtained by reaction-curing a polydectone ester containing a lactone ester component having a number of atoms of 5 or less and a polyincyanate. 2) The electrophotographic copying machine according to claim 1, wherein the content of the lacto/ester component having 5 or less carbon atoms in the borilactonoester is 30% or more. 3) Average molecular weight of poly2chton ester is 1000-4
000. The electrophotographic copying machine according to claim 1, which is 000.