JP7255338B2 - Cleaning device and image forming device - Google Patents

Description

The present invention relates to cleaning devices and image forming apparatuses.

In image forming apparatuses such as copiers, printers, and facsimiles, techniques described in Patent Documents 1 and 2 below are known for cleaning devices that clean image holding means such as photoreceptors and intermediate transfer belts.

Japanese Patent Application Laid-Open No. 2002-214689 as Patent Document 1 describes a configuration in which a cleaning blade has an edge layer (1) and a base layer (2). Patent document 1 describes that the edge layer (1) has a hardness of 70-81Hs, an impact resilience of 8-11%, a permanent elongation of 1-4%, and a thickness of 0.2-0.5 mm. ing. Also, the base layer (2) is described as having a hardness of 65 Hs, a rebound resilience of 35%, a permanent elongation of 0.5%, and a thickness of 1.5-2.8 mm. Further, the toner used has a weight average particle size of 6 to 8 μm.

Japanese Patent Laying-Open No. 2014-163995 as Patent Document 2 describes a blade member of a cleaning device, in which the blade member has an edge layer and a backup layer. In Patent Document 2, the edge layer has a 100% modulus of 6 MPa or more at 23° C., a rebound resilience of the edge layer of 13-14% at 10° C. and 16-23% at 23° C., and a permanent elongation of 1.5 MPa. 6-1.9% is described. The backup layer is described as having a rebound resilience of 7 to 25% at 10°C, 12 to 34% at 23°C, and a permanent elongation of 0.09 to 0.6%.

Japanese Patent Application Laid-Open No. 2002-214689 (“0027”, FIG. 1) JP 2014-163995 A (Claim 1, "0039")

The present invention improves long-term developer cleanability when the 100% modulus of the top layer is less than 9 MPa or greater than 13 MPa compared to when the elongation set of the back layer is greater than 1%. is a technical issue.

In order to solve the technical problem, the cleaning device of the invention described in claim 1 is
cleaning means for removing the developer adhering to the surface of the image holding means in contact with the image holding means, the surface layer being in contact with the image holding means, and the surface opposite to the image holding means on the surface layer. a coated backing layer;
with
The surface layer is made of a material with a 100% modulus of 9 MPa or more and 13 MPa or less,
The back layer is made of a material having a permanent elongation of 1% or less ,
The surface layer has a permanent elongation of less than 2%
It is characterized by

The invention according to claim 2 is the cleaning device according to claim 1,
The surface layer has a 100% modulus of 9 MPa or more and 12 MPa or less.

The invention according to claim 3 is the cleaning device according to claim 1 or 2,
The surface layer has an impact resilience of 15% or more and 40% or less.

The invention according to claim 4 is the cleaning device according to claim 3,
The surface layer has an impact resilience of 20% or more and 30% or less.

The invention according to claim 5 is the cleaning device according to any one of claims 1 to 4,
It is characterized in that the volume average particle size of the developer used is 5 μm or less.

The invention according to claim 6 is the cleaning device according to claim 5,
The developer is characterized in that a fatty acid metal salt is externally added to the developer.

In order to solve the technical problem, the image forming apparatus of the invention described in claim 7 is provided with:
an image holding means;
latent image forming means for forming a latent image on the image holding means;
a developing means for developing the latent image on the image holding means into an image;
a transfer means for transferring the image of the image holding means to a medium;
a cleaning device according to any one of claims 1 to 6 for cleaning the surface of the image holding means;
characterized by comprising

According to the inventions of claims 1 and 7 , when the 100% modulus of the surface layer is lower than 9 MPa or higher than 13 MPa, the elongation set of the back layer is longer than 1%. Cleanability of the developer can be improved. Further, according to the inventions of claims 1 and 7, deformation of the corners of the cleaning means can be reduced as compared with the case where the permanent elongation of the surface layer exceeds 2%.
According to the second aspect of the invention, developer passing through can be reduced compared to the case where the 100% modulus is higher than 12 MPa.
According to the third aspect of the invention, the local wear rate of the cleaning means can be reduced as compared with the case where the impact resilience is less than 15% or more than 40%.

According to the fourth aspect of the invention, the local wear rate of the cleaning means can be reduced to 0.3% or less compared to the case where the impact resilience is less than 20% or more than 30%.
According to the fifth aspect of the invention, the image quality can be improved as compared with the case where the volume average particle size of the developer is larger than 5 μm.
According to the sixth aspect of the invention, compared with the case where the fatty acid metal salt is not externally added, the wear of the image holding means can be reduced, and the cleanability of the developer when the image density is low can be improved .

FIG. 1 is an overall explanatory diagram of an image forming apparatus according to the first embodiment. FIG. 2 is an enlarged explanatory diagram of the visible image forming apparatus of the first embodiment. FIG. 3 is an explanatory diagram of the cleaning device of the first embodiment. FIG. 4 is an explanatory diagram of the experimental results of Experimental Example 1, and is a graph in which the horizontal axis represents the 100% modulus and the vertical axis represents the blade tack amount. FIG. 5 is an explanatory diagram of Experimental Example 2, FIG. 5A is an explanatory diagram of the average wear amount, and FIG. 5B is an explanatory diagram of the experimental results. FIG. 6 is an explanatory diagram of the experimental results of Experimental Example 3, and is a graph in which the horizontal axis is the impact resilience and the vertical axis is the blade local wear rate. 7A and 7B are explanatory diagrams of an example of an image obtained by observing the tip portion of the cleaning blade, FIG. 7A is an explanatory diagram of the cut surface and the mirror surface, FIG. 7B is an image obtained by observing the cut surface when the impact resilience is high, and FIG. 7C. 7D is an image obtained by observing the mirror surface when the impact resilience is low, and FIG. 7D is an image obtained by observing the cut surface when the impact resilience is low. FIG. 8 is an explanatory diagram of the experimental results of Experimental Example 4, and is a graph in which the horizontal axis represents the configuration of the cleaning blade and the vertical axis represents the amount of sag of the blade. FIG. 9 is an explanatory diagram of the experimental results of Experimental Example 4, and is a graph in which the horizontal axis represents the permanent elongation of the backing layer and the vertical axis represents the amount of fatigue of the blade. 10A and 10B are explanatory diagrams of the experimental results of Experimental Example 5, FIG. 10A is an explanatory diagram of the edge deformation amount, and FIG. 10B is a graph in which the horizontal axis indicates the permanent elongation of the surface layer and the vertical axis indicates the edge deformation amount.

Next, specific examples of embodiments of the present invention (hereinafter referred to as examples) will be described with reference to the drawings, but the present invention is not limited to the following examples.
To facilitate understanding of the following description, in the drawings, the front-rear direction is the X-axis direction, the left-right direction is the Y-axis direction, the vertical direction is the Z-axis direction, and arrows X, -X, Y, -Y, The directions or sides indicated by Z and -Z are forward, rearward, rightward, leftward, upward and downward, or frontward, rearward, rightward, leftward, upward and downward, respectively.
Also, in the figure, the “・” in the “○” means an arrow pointing from the back to the front of the paper, and the “×” in the “○” means the front of the paper shall mean an arrow pointing backwards from the
It should be noted that in the following explanation using the drawings, illustration of members other than those necessary for the explanation is omitted as appropriate for ease of understanding.

FIG. 1 is an overall explanatory diagram of an image forming apparatus according to the first embodiment.
FIG. 2 is an enlarged explanatory diagram of the visible image forming apparatus of the first embodiment.
In FIG. 1, a copying machine U as an example of an image forming apparatus includes a user interface UI as an example of an operation unit, a scanner unit U1 as an example of an image reading device, a feeder unit U2 as an example of a medium feeding device, and an image recording device. It has an image forming unit U3 and a medium processing unit U4 as an example of a device.

(Explanation of user interface UI)
The user interface UI has input buttons UIa used for starting copying and setting the number of copies. Further, the user interface UI has a display unit UIb on which the contents input by the input button UIa and the state of the copier U are displayed.

(Description of feeder unit U2)
In FIG. 1, the feeder unit U2 has a plurality of paper feed trays TR1, TR2, TR3, and TR4 as an example of medium containers. Further, the feeder section U2 has a medium supply path SH1 and the like for taking out the recording sheet S as an example of the image recording medium accommodated in each of the sheet feeding trays TR1 to TR4 and conveying it to the image forming section U3. are doing.

(Description of image forming unit U3 and medium processing device U4)
In FIG. 1, the image forming unit U3 has an image recording unit U3a for recording an image on the recording paper S conveyed from the feeder unit U2 based on the document image read by the scanner unit U1.
In FIGS. 1 and 2, the driving circuit D of the latent image forming device of the image forming unit U3 generates a corresponding driving signal based on the image information input from the scanner unit U1. to K latent image forming devices (latent image forming means) ROSy, ROSm, ROSc and ROSk. Photoreceptor drums Py, Pm, Pc, and Pk, which are examples of image carriers, are arranged below the latent image forming devices ROSy to ROSk.

The surfaces of the rotating photosensitive drums Py, Pm, Pc, and Pk are uniformly charged by charging rolls CRy, CRm, CRc, and CRk, which are examples of chargers, respectively. The surfaces of the photosensitive drums Py to Pk whose surfaces are charged are statically charged by laser beams Ly, Lm, Lc, and Lk as examples of latent image writing light output from the latent image forming devices ROSy, ROSm, ROSc, and ROSk. An electrostatic latent image is formed. The electrostatic latent images on the surfaces of the photosensitive drums Py, Pm, Pc, and Pk are examples of visible images of yellow Y, magenta M, cyan C, and black K by developing devices (developing means) Gy, Gm, Gc, and Gk. is developed into a developer image as
In the developing devices Gy to Gk, the developer consumed by development is replenished from developer cartridges Ky, Km, Kc, and Kk, which are examples of developer storage containers. The developer cartridges Ky, Km, Kc, and Kk are detachably attached to the developer supply device U3b.

The developer images on the surfaces of the photosensitive drums Py, Pm, Pc, and Pk are transferred onto an intermediate transfer belt B, which is an example of an intermediate transfer member, by primary transfer rolls T1y, T1m, T1c, and T1k, which are examples of primary transfer units. are sequentially superimposed on the primary transfer areas Q3y, Q3m, Q3c, and Q3k, and a color developer image is formed on the intermediate transfer belt B as an example of a multicolor visible image. The color developer image formed on the intermediate transfer belt B is conveyed to the secondary transfer area Q4.
In the case of only K-color image information, only the K-color photosensitive drum Pk and the developing device Gk are used, and only the K-color developer image is formed.
After the primary transfer, the photosensitive drums Py, Pm, Pc, and Pk are cleaned by drum cleaners CLy, CLm, CLc, and CLk, which are examples of image carrier cleaners, to remove residual developer, paper dust, and the like adhering to the surface. Residue is removed.

In Example 1, the photoreceptor drum Pk, charging roll CRk, and drum cleaner CLk are integrated as a K-color photoreceptor unit UK as an example of the image carrier unit. Similarly, for the other colors Y, M, and C, the photosensitive drums Py, Pm, and Pc, the charging rolls CRy, CRm, CRc, and the drum cleaners CLy, CLm, and CLc cause the photosensitive units UY, UM, and UC. It is configured.
A K-color visible image forming apparatus UK+Gk is composed of the K-color photosensitive unit UK and the developing device Gk having a developing roll R0k as an example of a developer holding member. Similarly, the Y, M, and C color visible light is generated by the Y, M, and C photoreceptor units UY, UM, and UC, and the developing devices Gy, Gm, and Gc having the developing rolls R0y, R0m, and R0c, respectively. Image forming apparatuses UY+Gy, UM+Gm, and UC+Gc are configured.

A belt module BM as an example of an intermediate transfer device is arranged below the photosensitive drums Py to Pk. The belt module BM includes the intermediate transfer belt B, a driving roll Rd as an example of a driving member for the intermediate transfer member, a tension roll Rt as an example of a tension imparting member, a walking roll Rw as an example of a meandering prevention member, and a driven member. It has a plurality of idler rolls Rf as an example, a backup roll T2a as an example of a facing member, and the primary transfer rolls T1y, T1m, T1c, and T1k. The intermediate transfer belt B is rotatably supported in the arrow Ya direction.

A secondary transfer unit Ut is arranged below the backup roll T2a. The secondary transfer unit Ut is an example of a final transfer member and has a secondary transfer roll T2b as an example of a secondary transfer member. The area where the secondary transfer roll T2b contacts the intermediate transfer belt B forms a secondary transfer area Q4. A backup roll T2a, which is an example of a facing member, faces the secondary transfer roll T2b with the intermediate transfer belt B interposed therebetween. A contact roll T2c, which is an example of a power supply member, is in contact with the backup roll T2a. A secondary transfer voltage having the same polarity as that of the developer is applied to the contact roll T2c.
The backup roll T2a, secondary transfer roll T2b, and contact roll T2c constitute a secondary transfer device T2.

A medium transport path SH2 is arranged below the belt module BM. The recording paper S fed from the medium supply path SH1 of the feeder unit U2 is conveyed to registration rolls Rr as an example of a conveying timing adjusting member by a conveying roll Ra as an example of a medium conveying member. The registration roll Rr conveys the recording sheet S downstream in time with the developer image formed on the intermediate transfer belt B being conveyed to the secondary transfer area Q4. The recording paper S sent out by the registration rolls Rr is guided by the paper guide SGr on the registration side and the paper guide SG1 before transfer, and conveyed to the secondary transfer area Q4.
The developer image on the intermediate transfer belt B is transferred onto the recording paper S by the secondary transfer device T2 when passing through the secondary transfer area Q4. In the case of color developer images, the developer images that have been primarily transferred over the surface of the intermediate transfer belt B are secondarily transferred onto the recording sheet S all at once.
The primary transfer rolls T1y to T1k, the secondary transfer device T2, and the intermediate transfer belt B constitute a transfer device (transfer means) T1y to T1k+T2+B of the first embodiment.

After the secondary transfer, the intermediate transfer belt B is cleaned by a belt cleaner CLB, which is an example of an intermediate transfer member cleaning device, arranged downstream of the secondary transfer area Q4. The belt cleaner CLB removes from the intermediate transfer belt B residuals such as developer and paper dust that have not been transferred in the secondary transfer area Q4.

The recording paper S onto which the developer image has been transferred is guided by a post-transfer paper guide SG2 and sent to a medium transport belt BH, which is an example of a transport member. The medium conveying belt BH conveys the recording paper S to the fixing device F. As shown in FIG.
The fixing device F has a heating roll Fh as an example of a heating member and a pressure roll Fp as an example of a pressure member. The recording paper S is conveyed to the fixing area Q5, which is the area where the heating roll Fh and the pressure roll Fp are in contact. The developer image on the recording paper S is heated and pressurized by the fixing device F when passing through the fixing area Q5, and is fixed.
The visible image forming devices UY+Gy to UK+Gk, the transfer devices T1y to T1k+T2+B, and the fixing device F constitute an image recording unit U3a as an example of the image forming means of the first embodiment.

A switching gate GT1, which is an example of a switching member, is provided on the downstream side of the fixing device F. As shown in FIG. The switching gate GT1 selectively switches the recording paper S that has passed through the fixing area Q5 to either the discharge path SH3 or the reverse path SH4 on the side of the media processing device U4. The recording paper S transported to the discharge path SH3 is transported to the paper transport path SH5 of the medium processing device U4. A curl correction member U4a, which is an example of a warpage correction member, is arranged in the sheet transport path SH5. The curl correcting member U4a corrects the curl of the recording paper S that has been conveyed. The curl-corrected recording paper S is discharged onto a discharge tray TH1, which is an example of a medium discharge unit, with the image fixing surface facing upward by a discharge roll Rh, which is an example of a medium discharge member.

The recording paper S conveyed to the reversing path SH4 side of the image forming unit U3 by the switching gate GT1 is conveyed to the reversing path SH4 of the image forming unit U3 through a second gate GT2 as an example of a switching member.
At this time, when the image fixing surface of the recording paper S is to be discharged downward, the conveying direction of the recording paper S is reversed after the rear end of the recording paper S in the conveying direction passes the second gate GT2. Here, the second gate GT2 of Example 1 is composed of a thin-film elastic member. Therefore, the second gate GT2 allows the recording paper S transported to the reversing path SH4 to pass through as it is, and when the passing recording paper S is reversed, that is, is switched back, it is guided to the transport paths SH3 and SH5. do. Then, the recording paper S that has been switched back passes through the curl correction member U4a and is discharged to the discharge tray TH1 with the image fixing surface facing downward.

A circulation path SH6 is connected to the reversing path SH4 of the image forming unit U3, and a third gate GT3 as an example of a switching member is arranged at the connection part. Further, the downstream end of the reversing path SH4 is connected to the reversing path SH7 of the media processing device U4.
The recording paper S conveyed to the reversing path SH4 through the switching gate GT1 is conveyed to the reversing path SH7 side of the medium processing device U4 by the third gate GT3. Like the second gate GT2, the third gate GT3 of the first embodiment is composed of a thin-film elastic member. Therefore, the third gate GT3 allows the recording paper S conveyed along the reverse path SH4 to pass through once, and when the recording paper S that has passed through is switched back, guides it to the circulation path SH6.

The recording paper S transported to the circulation path SH6 is re-fed to the secondary transfer area Q4 through the medium transport path SH2, and the second side is printed.
The elements indicated by the symbols SH1 to SH7 constitute the sheet conveying path SH. The elements indicated by the symbols SH, Ra, Rr, Rh, SGr, SG1, SG2, BH, and GT1 to GT3 constitute the sheet conveying device SU of the first embodiment.

(Description of cleaning device)
FIG. 3 is an explanatory diagram of the cleaning device of the first embodiment.
In the following description, the drum cleaners CLy, CLm, CLc, and CLk and the belt cleaner CLB will be described as examples of cleaning devices. description of the other cleaners CLy, CLm, CLc, and CLB will be omitted.
In FIG. 3, the drum cleaner CLk of Example 1 has a housing 1 as an example of a cleaning container. The housing 1 supports a cleaning blade 2 as an example of cleaning means. The cleaning blade 2 according to the first embodiment has a tip contacting the photosensitive drum Pk as an example of an image holding means, and a base end supported by the housing 1 . The cleaning blade 2 of Example 1 has a surface layer 2a on the photosensitive drum Pk side and a back layer 2b on the housing 1 side. Therefore, the front end portion of the surface layer 2 a contacts the photosensitive drum Pk, and the base end portion of the back layer 2 b is supported by the housing 1 .

The surface layer 2a of Example 1 is made of a material having a 100% modulus at 23° C. of 9 MPa or more and 13 MPa or less. If the 100% modulus exceeds 13 MPa, the developer is likely to slip through the cleaning blade 2, causing poor cleaning. Therefore, if the 100% modulus is 13 MPa or less, the developer is less likely to pass through. Further, when the 100% modulus is less than 9 MPa, the cleaning blade 2 tends to wear out.
Further, the surface layer 2a of Example 1 is made of a material having a repulsion resilience of 15% or more and 40% or less, and it is particularly preferable that the repulsion resilience is 20% or more and 30% or less. If the impact resilience is less than 15%, the edge (the corner that contacts the photosensitive drum Pk) is likely to be chipped, and if the impact resilience exceeds 40%, the edge is likely to be torn off. Therefore, when the impact resilience is less than 15% or more than 40%, the local wear rate (edge loss rate per unit length) such as edge chipping or edge tearing increases, but in Example 1, this is improved. be done. In particular, when the impact resilience is 20 to 30%, local wear is particularly suppressed.

Further, the surface layer 2a of Example 1 is made of a material having a permanent elongation of 2% or less. When the elongation set exceeds 2%, the deformation of the edge becomes larger than 1.5 mm, which is suppressed in Example 1.
Further, the back layer 2b of Example 1 is made of a material having a permanent elongation of 1% or less. When the elongation set exceeds 1%, the settling of the blade becomes larger than 0.1 mm, but this is suppressed in Example 1.
Further, in the copier U of Example 1, a developer having a volume average particle size of 5 μm or less is used. Coulter Multisizer II (manufactured by Beckman-Coulter) can be used to measure the volume average particle size of the developer. In this case, depending on the particle size level of the developer, the optimum aperture can be used for measurement. In particular, in Example 1, a developer to which a fatty acid metal salt is externally added is used. Examples of fatty acid metal salts include compounds of fatty acids such as stearic acid, lauric acid, ricinoleic acid and octylic acid and metals such as lithium, magnesium, calcium, barium and zinc. In this embodiment, zinc stearate is used.

(Action of Example 1)
In the copier U of the first embodiment having the above-described configuration, the cleaning blade 2 is composed of the surface layer 2a on the side of the photosensitive drum Pk and the back layer 2b on the side of the housing 1. The surface layer 2a side is Compared to the back layer 2b side, it is made of a material having a larger permanent elongation. The surface layer 2a has a 100% modulus of 9 to 13 MPa, an impact resilience of 15 to 40%, and a permanent elongation of 2% or less, and the back layer 2b has a permanent elongation of 1% or less. This improves developer penetration, wear, local wear, and edge deformation during cleaning. Therefore, compared to the case where the surface layer 2a has a low 100% modulus or the back layer 2b has a large elongation set, the long-term developer cleanability is improved.

In particular, when a so-called small particle size developer having a volume average particle size of 5 .mu.m or less is used, the resolution of image formation can be increased and the image quality can be improved. In the developer to which the fatty acid metal salt is externally added, the lubricating effect of the fatty acid metal salt reduces abrasion of the photoreceptor and stabilizes cleaning at low image density. However, during continuous printing with a high image density, the adhesive force increases due to the smaller diameter of the developer (reduced diameter makes the developer lighter, but if the potential remains the same and the electrostatic force remains the same, the adhesive force (unit: The electrostatic force per weight) increases.In addition, the fatty acid metal salt is damaged by discharge, resulting in an increase in stickiness.Therefore, filming (developer adheres in a film form) occurs on the photoreceptor drums Py to Pk. phenomenon) occurs easily, and line streaks (image defects) occur on the image. As the rate increases, it is assumed that the cleaning blade 2 wears locally and developer slips therefrom and accumulates, leading to filming.
On the other hand, in Example 1, the material strength is improved by increasing the modulus of the surface layer 2a, thereby suppressing the aggregation and penetration of the external additive, which causes local wear. Stick-slip (a phenomenon in which the cleaning blade moves while rubbing the surface of the photoreceptor as if it were flipped when the edge part deformed by being dragged by the rotation of the photoreceptor recovers elastically) due to the low repulsion elasticity of the surface layer 2a. The amplitude of the friction is reduced to shorten the sliding distance, thereby reducing wear.

(Experimental example)
Next, an experiment was conducted to confirm the effects of the first embodiment. In Experimental Examples 1 to 3, DocuCentre VIC7171 manufactured by Fuji Xerox Co., Ltd. was used, and the blade contact conditions were a linear pressure of 2.5 gf/mm and a set angle of 26°, and the blade was evaluated after running 50,000 sheets.
(Experimental example 1)
In Experimental Example 1, the relationship between the 100% modulus of the surface layer 2a and the amount of blade tack, that is, the contact width between the surface layer 2a and the photoreceptor drum Pk along the rotational direction of the photoreceptor drum Pk was measured. For the measurement, a plurality of test pieces with different 100% modulus were used to measure the blade tack amount with a laser microscope (VK-9500 manufactured by Keyence Corporation).
FIG. 4 shows the experimental results.

FIG. 4 is an explanatory diagram of the experimental results of Experimental Example 1, and is a graph in which the horizontal axis represents the 100% modulus and the vertical axis represents the blade tack amount.
In FIG. 4, as the blade tack amount increases, the contact area increases, the cleaning performance improves, and the developer is less likely to pass through. Then, when the allowable value of the blade tack amount is 5 μm or more, the 100% modulus is 13 MPa or less, and when the allowable value of the blade tack amount is 9 μm or more, the 100% modulus is 12 MPa or less, and the 100% modulus is 13 MPa or less. , it was confirmed that the developer did not slip through.

(Experimental example 2)
FIG. 5 is an explanatory diagram of Experimental Example 2, FIG. 5A is an explanatory diagram of the average wear amount, and FIG. 5B is an explanatory diagram of the experimental results.
In Experimental Example 2, the relationship between the 100% modulus of the surface layer 2a and the average wear amount of the cleaning blade 2 was measured. For the measurement, a plurality of test pieces with different 100% moduli similar to Experimental Example 1 were used, and the average wear amount was measured with a laser microscope. In addition, in Experimental Example 2, as shown in FIG. 5A, the cross-sectional area 11 in which the edge of the surface layer 2A is worn on average is taken as the average wear amount.
The experimental results are shown in FIG. 5B.

Note that FIG. 5B is a graph in which the horizontal axis represents 100% modulus and the vertical axis represents the average wear amount of the blade. In FIG. 5B, when the average wear amount (μm ² ) increases, the contact pressure between the cleaning blade 2 and the photosensitive drum Pk decreases, the cleaning performance deteriorates, and the life of the cleaning blade 2 also shortens. It was confirmed that when the 100% modulus is 9 MPa, the average wear amount is 4 (μm ² ) or less, the cleaning performance of the cleaning blade 2 is ensured over a long period of time, and the service life is extended.

(Experimental example 3)
FIG. 6 is an explanatory diagram of the experimental results of Experimental Example 3, and is a graph in which the horizontal axis is the impact resilience and the vertical axis is the blade local wear rate.
7A and 7B are explanatory diagrams of an example of an image obtained by observing the tip portion of the cleaning blade, FIG. 7A is an explanatory diagram of the cut surface and the mirror surface, FIG. 7B is an image obtained by observing the cut surface when the impact resilience is high, and FIG. 7C. 7D is an image obtained by observing the mirror surface when the impact resilience is low, and FIG. 7D is an image obtained by observing the cut surface when the impact resilience is low.
In Experimental Example 3, the relationship between the impact resilience of the surface layer 2a and the local wear rate of the cleaning blade 2 was measured. The measurement was performed with a laser microscope using a plurality of test pieces with different 100% moduli in the same manner as in Experimental Example 1. The local wear rate was derived by calculating (the length in the width direction where local wear occurs)/(full width), ie, the edge loss rate per unit length. In FIG. 7A, in Example 1, observation is performed with the surface on the upstream side of the cleaning blade 2 as the cut surface 12 and the surface on the downstream side as the mirror surface 13 with respect to the rotation direction of the photosensitive drum Pk. Then, the local wear rate of each surface 12, 13 is derived. In the graph, the maximum value of the local wear rate on each surface 12, 13 can be used as the experimental result, or the average value can be used as the experimental result.
6 and 7 show experimental results.

In FIGS. 6 and 7, if the impact resilience exceeds 40%, as shown in FIG. 7B, local wear where the edge is locally torn off is likely to occur. Also, if the rebound resilience is less than 15%, localized abrasion such as chipping of the edge tends to occur as shown in FIGS. 7C and 7D. In contrast, in Example 1, the impact resilience of the surface layer 2a is 15% to 40%, and local wear such as tearing and chipping is reduced. In particular, as shown in FIG. 6, when the impact resilience is 20 to 30%, the local wear rate is suppressed to 0.3% or less, which is more preferable.

(Experimental example 4)
In Experimental Example 4, the relationship between the permanent elongation of the surface layer 2a and the back layer 2b and the settling of the cleaning blade 2 was measured. The experiment was carried out by using DocuCentre VIC7171 manufactured by Fuji Xerox Co., Ltd., setting the biting amount of the cleaning blade 2 into the photosensitive drum Pk to 1 mm, and storing it for 72 hours at a temperature of 45° C. and a humidity of 90% RH. To measure the sag, the distance from the center of rotation of the photoreceptor drum Pk to the tip of the cleaning blade 2 before contact between the cleaning blade 2 and the photoreceptor drum Pk is first measured. After 72 hours have passed since the attachment, the photosensitive drum Pk is removed. After 30 minutes, the distance from the tip of the cleaning blade 2 to the center of rotation of the photosensitive drum Pk is measured, and the difference (from deformation to recovery) is calculated. length) was measured as settling.

Further, in Experimental Example 4, FIG. 8 shows the experimental results in the case of using a back layer 2b of 0.3% permanent elongation and changing the material of the surface layer. FIG. 9 shows the results of an experiment conducted using a plurality of materials with different elongations set as the back layer 2b.
For each cleaning blade 2 in FIG. 9, the cleaning performance was evaluated when untransferred developer (one sheet of A3 size paper) with an image density of 100% was plunged into the blade in a copier. The conditions for image formation were 10° C. and 10% RH, and the blade contact conditions were a linear pressure of 2.5 gf/mm and a set angle of 26°. The evaluation was made as follows: no developer coming off, .DELTA., and band-like developer coming off.

FIG. 8 is an explanatory diagram of the experimental results of Experimental Example 4, and is a graph in which the horizontal axis represents the configuration of the cleaning blade and the vertical axis represents the amount of sag of the blade.
FIG. 9 is an explanatory diagram of the experimental results of Experimental Example 4, and is a graph in which the horizontal axis represents the permanent elongation of the backing layer and the vertical axis represents the amount of fatigue of the blade.
In FIG. 8, when the target value of the amount of squat is 0.1 mm, there is no problem with squat when the permanent elongation of the surface layer 2a is 0.7% to 2.4%. Moreover, there was no problem with the presence or absence of the back layer 2b. In FIG. 9, when the target value of the settling amount is 0.1 mm, it was confirmed from FIG. 9 that the permanent elongation of the back layer 2b is preferably 1% or less.
From the evaluation of cleanability in FIG. 9, it was confirmed that it is preferable from the viewpoint of cleanability that the surface layer 2a has a permanent elongation of 2% or less and the back layer 2b has a permanent elongation of 1% or less.

(Experimental example 5)
10A and 10B are explanatory diagrams of the experimental results of Experimental Example 5, FIG. 10A is an explanatory diagram of the edge deformation amount, and FIG. 10B is a graph in which the horizontal axis indicates the permanent elongation of the surface layer and the vertical axis indicates the edge deformation amount. Edge deformation is the amount of plastic deformation of the edge of the blade.
In Experimental Example 5, the relationship between the permanent elongation of the surface layer 2a and the back layer 2b and the edge deformation of the cleaning blade 2 was measured. The experiment was conducted under the same experimental conditions as in Experimental Example 4. As for the amount of change in the edge, the amount of edge deformation 21 based on the mirror surface was measured with a laser microscope one day after the photoreceptor was removed after storage for 72 hours as described above.
Further, in Experimental Example 5, experiments were conducted by using a back layer 2b having a permanent elongation of 0.3% and changing the material of the surface layer. Experimental results are shown in FIG. 10B.
In FIG. 10, it was confirmed that the permanent elongation of the surface layer 2a is preferably 2% or less when the target value of the edge deformation amount is 1.5 μm or less.

(Change example)
Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the gist of the present invention described in the scope of claims. is possible. Modified examples (H01) to (H03) of the present invention are exemplified below.
(H01) In the above-described embodiment, the copying machine U is illustrated as an example of the image forming apparatus, but the present invention is not limited to this, and can be applied to FAX, or has multiple functions such as FAX, printer, and copying machine. It can be applied to multi-function machines and the like. In addition, the present invention is not limited to an electrophotographic image forming apparatus, and can be applied to any image forming apparatus such as an inkjet recording method, a thermal head method, a printing machine such as a lithograph, and the like. Further, the image forming apparatus is not limited to a multicolor image forming apparatus, and may be configured by a single color, so-called monochrome image forming apparatus.

(H02) In the above embodiments, drum cleaners CLy to CLk and belt cleaner CLB were exemplified as cleaning devices, but the present invention is not limited to these. It can also be applied to a charging roll cleaner, a transfer roll cleaner, and the like.
(H03) In the above examples, it is preferable that the particle size of the developer is small, but it is also possible to apply particles larger than those exemplified in the examples. Further, although a developer to which a fatty acid metal salt is externally added is preferable, a developer that does not contain a fatty acid metal salt is also applicable.

2 ... cleaning means,
2a ... surface layer,
2b... back layer,
CLy, CLm, CLc, CLk, CLB... cleaning device,
Gy, Gm, Gc, Gk... developing means,
Py, Pm, Pc, Pk, B... image holding means,
ROSy, ROSm, ROSc, ROSk... latent image forming means,
S... medium,
T1y to T1k+T2+B... transfer means,
U: image forming apparatus.

Claims (7)

cleaning means for removing the developer adhering to the surface of the image holding means in contact with the image holding means, the surface layer being in contact with the image holding means, and the surface opposite to the image holding means on the surface layer. a coated backing layer;
with
The surface layer is made of a material with a 100% modulus of 9 MPa or more and 13 MPa or less,
The back layer is made of a material having a permanent elongation of 1% or less ,
The surface layer has a permanent elongation of less than 2%
A cleaning device characterized by: The cleaning device according to claim 1, wherein the surface layer has a 100% modulus of 9 MPa or more and 12 MPa or less. The cleaning device according to claim 1 or 2, wherein the surface layer has an impact resilience of 15% or more and 40% or less. The cleaning device according to claim 3, wherein the surface layer has an impact resilience of 20% or more and 30% or less. 5. The cleaning device according to claim 1, wherein the volume average particle size of the developer used is 5 [mu]m or less. 6. The cleaning device according to claim 5, wherein the developer is externally added with a fatty acid metal salt. an image holding means;
latent image forming means for forming a latent image on the image holding means;
a developing means for developing the latent image on the image holding means into an image;
a transfer means for transferring the image of the image holding means to a medium;
a cleaning device according to any one of claims 1 to 6 for cleaning the surface of the image holding means;
An image forming apparatus comprising:

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