Image forming apparatus

Abstract

To suppress occurrence of faulty cleaning, while suppressing turn-up of a blade.SOLUTION: When an average value of a free length L1 (mm) in an image forming area in a width direction of an elastic blade 1 is defined as an average free length L1a (mm), an average value of a free length L2 (mm) outside a developing area in the width direction of the elastic blade 1 as an average free length L2a (mm), and an absolute value of a difference between the average free length L1a and the average free length L2a as a free length difference ΔL (mm), an image forming apparatus 100 satisfies following formulas: L2a≥1.2×L1a; L2≥L2a-ΔL×0.2; and L1≤L1a+ΔL×0.2.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a multifunction machine having a plurality of the functions of these machines, which uses an electrophotographic system or an electrostatic recording system. [Background technology]

[0002] Conventionally, image forming apparatuses such as copying machines using an electrophotographic system have been provided with a cleaning device that removes toner (residual toner) remaining on an image carrier such as a photoconductor or an intermediate transfer body after a toner image is transferred from the image carrier to a transferee.

[0003] As a cleaning device, the following blade cleaning device is widely used. The blade cleaning device has a cleaning blade as a cleaning member, which includes a plate-shaped elastic member (herein also referred to as "elastic blade") made of an elastic material such as rubber, and a support member such as a supporting metal plate that supports the member. The elastic blade is often fixed to the support member by adhesion or the like, with a part of its short side overlapping the support member along the long side. In particular, a counter type in which the elastic blade is brought into contact with the surface of the image carrier so as to face the moving direction of the surface of the image carrier is generally adopted for the blade cleaning device, because of its high cleaning performance.

[0004] However, in this counter-type blade cleaning device, it is known that when the frictional force between the elastic blade and the image carrier becomes large, a problem called "blade curling" can occur, in which the elastic blade curls up in the moving direction of the surface of the image carrier. It is also known that when the frictional force between the elastic blade and the image carrier becomes large, problems such as squealing (generation of abnormal noise) and chattering (generation of abnormal vibration) of the elastic blade can occur, but "blade curling" will be mainly used to represent these problems.

[0005] Patent Document 1 proposes a configuration in which the free length at the longitudinal ends of the elastic blade is made longer than the free length at the longitudinal center of the elastic blade to suppress the occurrence of blade curling. Note that the "free length" of the elastic blade refers to the short-side length of the part protruding from a support member or a regulating member that is provided in contact with or facing the surface of the elastic blade and that regulates deformation on the free end side of the elastic blade.

[0006] Moreover, Patent Document 2 proposes a configuration in which the longitudinal end of the elastic blade is impregnated with an isocyanate compound and then cured, thereby suppressing blade curling. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2006-259394 A [Patent Document 2] JP 2009-42581 A Summary of the Invention [Problem to be solved by the invention]

[0008] However, Patent Document 1 only specifies the relationship between the free length at the longitudinal end of the elastic blade and the free length at the longitudinal center. Therefore, if the region where the free length of the elastic blade is increased is narrow, the blade may still be curled up. Also, if the region where the free length of the elastic blade is increased is wide, poor cleaning may occur.

[0009] Incidentally, Patent Document 2 does not disclose anything about varying the free length of the elastic blade depending on the position in the longitudinal direction of the elastic blade.

[0010] SUMMARY OF THE PRESENTLY PREFERRED EMBODIMENTS Accordingly, an object of the present invention is to suppress blade curling while suppressing the occurrence of poor cleaning. [Means for solving the problem]

[0011] The above object is achieved by the image forming apparatus according to the present invention. In summary, the present invention provides a cleaning member for removing developer from the surface of the image carrier, the cleaning member comprising an elastic blade whose free end abuts against the surface of the image carrier along a width direction substantially perpendicular to the moving direction of the surface of the image carrier, and a regulating portion for regulating the free length of the elastic blade at a base end side opposite to the free end in a direction intersecting the width direction of the elastic blade, and the end of a developing region in which the developing member can carry developer is a region at both ends in the width direction. an image forming apparatus characterized in that the elastic blade is positioned outside the edge of an image forming area where an image can be formed with a developer on the image carrier, and the average value of the free lengths L1 [mm] of the elastic blade in the image forming area in the width direction is defined as an average free length L1a [mm], the average value of the free lengths L2 [mm] of the elastic blade outside the development area in the width direction is defined as an average free length L2a [mm], and the absolute value of the difference between the average free length L1a and the average free length L2a is defined as a free length difference ΔL [mm], satisfying the following equations: L2a≧1.2×L1a, L2≧L2a-ΔL×0.2, and L1≦L1a+ΔL×0.2. Effect of the Invention

[0012] According to the present invention, it is possible to suppress blade curling and also suppress the occurrence of poor cleaning. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic cross-sectional view of an image forming apparatus. [Diagram 2] FIG. 2 is an explanatory diagram of a longitudinal arrangement of main parts of the image forming apparatus. [Diagram 3] FIG. 1 is a schematic diagram of a conventional cleaning blade. [Figure 4] FIG. 2 is a schematic diagram showing a deformation state of a conventional cleaning blade in a high μ area. [Diagram 5]FIG. 2 is a schematic diagram of a cleaning blade according to a first embodiment. [Figure 6] FIG. 2 is a schematic diagram showing a deformation state of the cleaning blade in a high μ region of Example 1. [Figure 7] FIG. 2 is an explanatory diagram of the longitudinal width of each portion of the cleaning blade of the first embodiment. [Figure 8] 1 is a table showing experimental results in Example 1. [Figure 9] 1 is a table showing experimental results in Example 1. [Figure 10] 1 is a table showing experimental results in Example 1. [Figure 11] FIG. 11 is an explanatory diagram of a modified embodiment of the first embodiment. [Figure 12] 13 is a table showing experimental results of a modified embodiment of Example 1. [Figure 13] FIG. 6 is a schematic diagram of a cleaning blade according to a second embodiment. [Figure 14] FIG. 11 is a schematic diagram of a cleaning blade according to a third embodiment. [Figure 15] 11 is an explanatory diagram of the longitudinal width of each portion of a cleaning blade according to a third embodiment. FIG. [Figure 16] 13 is a table showing experimental results in Example 3. [Figure 17] FIG. 13 is an explanatory diagram of the longitudinal arrangement of each part in the fourth embodiment. [Figure 18] FIG. 2 is a schematic diagram showing a deformation state of a conventional cleaning blade in a high μ area. [Figure 19] FIG. 11 is a schematic diagram of a cleaning blade according to a fourth embodiment. [Figure 20] FIG. 11 is a schematic diagram showing a deformation state of the cleaning blade in a high μ area of ​​Example 4. [Figure 21] 5 is an explanatory diagram of a contact pressure distribution in the vicinity of an end portion of a cleaning blade. FIG. [Figure 22] FIG. 11 is a schematic diagram showing the experimental results in Example 4. [Diagram 23] FIG. 11 is a schematic diagram showing the experimental results in Example 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, the image forming apparatus according to the present invention will be described in more detail with reference to the drawings.

[0015] [Example 1] 1. Overall configuration and operation of the image forming apparatus 1 is a schematic cross-sectional view of an image forming apparatus 100 according to this embodiment. The image forming apparatus 100 according to this embodiment is a tandem-type full-color printer employing an electrophotographic method and an intermediate transfer method, in which a plurality of image forming units (image forming sections) 109Y, 109M, 109C, and 109K are arranged along the moving direction of the surface of an intermediate transfer belt 101. In this embodiment, the image forming apparatus 100 has, as a plurality of image forming units, image forming units 109Y, 109M, 109C, and 109K that form yellow, magenta, cyan, and black images, respectively.

[0016] For example, when forming a full-color image, in the yellow image forming unit 109Y, a yellow toner image is formed on the photosensitive drum 103Y, which is then primarily transferred onto the intermediate transfer belt 101. In the magenta image forming unit 109M, a magenta toner image is formed on the photosensitive drum 103M, which is then primarily transferred and superimposed onto the yellow toner image on the intermediate transfer belt 101. Similarly, in the cyan and black image forming units 109C and 109K, a cyan toner image and a black toner image are formed on the photosensitive drums 103C and 103K, respectively, which are then primarily transferred and superimposed onto the toner images previously transferred onto the intermediate transfer belt 101.

[0017] The toner image primarily transferred onto the intermediate transfer belt 101 is secondarily transferred onto a recording material P. The recording material P onto which the toner image has been secondarily transferred is separated from the intermediate transfer belt 101 (curvature separation in this embodiment) and sent to a fixing device 112. The fixing device 112 heats and presses the recording material P with a fixing roller 112a and a pressure roller 112b to melt the toner and fix the image onto the surface of the recording material P. Thereafter, the recording material P onto which the image has been fixed is discharged (output) to the outside (outside the machine) of the main body of the image forming apparatus 100.

[0018] The image forming process will be further described. The configurations of the image forming units 109Y, 109M, 109C, and 109K are substantially the same except that the colors of the toners used in the developing devices 106Y, 106M, 106C, and 106K are different, that is, yellow, magenta, cyan, and black, respectively. Elements having the same or corresponding functions or configurations for each color may be generally described by omitting the Y, M, C, or K at the end of the reference numerals indicating that the elements are for any of the colors.

[0019] The image forming unit 109 has a photosensitive drum 103, which is a drum-type (cylindrical) photosensitive member (electrophotographic photosensitive member) as a first image carrier. The image forming unit 109 also has the following means arranged around the photosensitive drum 103. First, the image forming unit 109 has a charging roller 104, which is a roller-type charging member, as a charging means. The image forming unit 109 also has an exposure device (laser beam scanner) 105 as an exposure means. The image forming unit 109 also has a developing device 106 as a developing means. The image forming unit 109 also has a primary transfer roller 107, which is a roller-type primary transfer member, as a primary transfer means. The image forming unit 109 also has a photosensitive cleaning device 180, which is a photosensitive cleaning means, equipped with a photosensitive cleaning blade 108.

[0020] The photosensitive drum 103 is configured by forming a photosensitive layer with a negative charging polarity on the surface of an aluminum tube. The photosensitive drum 103 is rotated by a drive motor (not shown) as a drive means in the direction of arrow R1 in FIG. 1 (clockwise direction) at a peripheral speed (process speed) of 0.3 m / s.

[0021] A negative DC voltage is applied to the charging roller 104 as a charging voltage (charging bias), and the charging roller 104 uniformly charges the surface of the photosensitive drum 103 to a predetermined potential of negative polarity.

[0022] The exposure device 105 scans an ON / OFF modulated laser beam using a rotating mirror based on scanning line image data obtained by developing images of separated colors corresponding to each image forming unit 109, and irradiates the charged surface of the photosensitive drum 103. In this way, the exposure device 105 writes an electrostatic image (electrostatic latent image) on the photosensitive drum 103 according to the image data.

[0023] The developing device 106 frictionally charges a two-component developer containing a toner (non-magnetic toner particles) with a negative charge polarity and a carrier (magnetic carrier particles) by a stirring member. The developer is transported by a transport member and carried on a developing sleeve 161 as a developer carrier (developing member). The developer carried on the developing sleeve 161 is regulated in thickness by a regulating blade (not shown) and then transported to a portion facing the photosensitive drum 103. The developing sleeve 161 is held at a predetermined distance from the photosensitive drum 103. An oscillating voltage in which a negative DC voltage and an AC voltage are superimposed is applied to the developing sleeve 161 as a developing voltage (developing bias). As a result, the negatively charged toner moves to an exposed portion (image portion) on the photosensitive drum 103 that is relatively more positive than the potential of the developing sleeve 161, and an electrostatic image is developed. In this manner, in this embodiment, toner charged with the same polarity (negative in this embodiment) as the charge polarity of the photosensitive drum 103 adheres to the exposed portion (image portion) in which the absolute value of the potential has been reduced by being exposed after being uniformly charged (reverse development method). In this embodiment, the normal charge polarity of the toner, which is the main charge polarity of the toner during development, is negative.

[0024] In this embodiment, the toner may be a known toner obtained by adding a coloring agent, a charge control agent, etc. to a binder resin. In addition, the toner may preferably have a volume average particle size of 5 μm or more and 15 μm or less. In this embodiment, toner with a volume average particle size of 6 μm is used for all colors of yellow, magenta, cyan, and black.

[0025] An intermediate transfer belt 101, which is an intermediate transfer body composed of an endless belt (belt member) as a second image carrier, is disposed so as to face each photosensitive drum 103. The intermediate transfer belt 101 is stretched around a driving roller 110, auxiliary rollers 113 and 114, and a tension roller 115 as a plurality of tension rollers, and tensioned with a predetermined tension. The driving roller 110 is a driving member that transmits a driving force to the intermediate transfer belt 101. The auxiliary rollers 113 and 114 form an image transfer surface of the intermediate transfer belt 101 onto which a toner image is transferred from each photosensitive drum 103. The tension roller 115 applies a predetermined tension to the intermediate transfer belt 101. The intermediate transfer belt 101 rotates (moves in a circular motion) in the direction of arrow R2 in FIG. 1 (counterclockwise direction) at a peripheral speed (process speed) corresponding to the peripheral speed of the photosensitive drum 103, as the driving roller 110 is driven to rotate by a driving motor (not shown) as a driving means. The driving roller 110 also functions as a secondary transfer inner roller disposed in the secondary transfer portion T2. ​​The number of rollers around which the intermediate transfer belt 101 is stretched is not limited to the number in this embodiment.

[0026] Primary transfer rollers 107 are disposed on the inner circumferential surface side of the intermediate transfer belt 101 in correspondence with each photosensitive drum 103. The primary transfer rollers 107 press the intermediate transfer belt 101 toward the photosensitive drums 103 to form a primary transfer portion (primary transfer nip) T1 where the photosensitive drums 103 and the intermediate transfer belt 101 come into contact with each other. A positive DC voltage, which is the opposite polarity to the normal charging polarity of the toner, is applied to the primary transfer rollers 107 as a primary transfer voltage (primary transfer bias). As a result, the toner image carried on the photosensitive drum 103 is primarily transferred to the rotating intermediate transfer belt 101 at the primary transfer portion T1.

[0027] A secondary transfer roller (secondary transfer outer roller) 111, which is a roller-type secondary transfer member serving as a secondary transfer means, is disposed at a position facing the driving roller 110 on the outer peripheral surface side of the intermediate transfer belt 101. The secondary transfer roller 111 abuts against the outer surface of the intermediate transfer belt 101, the inner surface of which is supported by the driving roller (opposing roller, secondary transfer inner roller) 110, to form a secondary transfer portion (secondary transfer nip) T2. The secondary transfer roller 111 is pressed against the driving roller 110 via the intermediate transfer belt 101. A positive DC voltage, which is the opposite polarity to the normal charging polarity of the toner, is applied to the secondary transfer roller 111 as a secondary transfer voltage (secondary transfer bias). As a result, the toner image carried on the intermediate transfer belt 101 is secondarily transferred to the recording material P, which is conveyed while being sandwiched between the intermediate transfer belt 101 and the secondary transfer roller 111, at the secondary transfer portion T2.

[0028] The recording material P onto which the toner image has been secondarily transferred is transported to the fixing device 112 as described above, and after undergoing image fixing processing, is discharged (output) outside the main body of the image forming apparatus 100 (outside the machine).

[0029] The toner remaining on the photosensitive drum 103 after the primary transfer (primary transfer residual toner) is removed from the surface of the photosensitive drum 103 and collected by the photosensitive cleaning device 180. In this embodiment, the photosensitive cleaning device 180 is a counter-type blade cleaning device. The photosensitive cleaning device 180 has a photosensitive cleaning container 181 and a photosensitive cleaning blade 108 as a cleaning member. The photosensitive cleaning blade 108 abuts against the surface of the photosensitive drum 103 so as to face the moving direction of the surface of the photosensitive drum 103, scrapes off the primary transfer residual toner from the surface of the rotating photosensitive drum 103, and collects it in the photosensitive cleaning container 181. The photosensitive cleaning blade 108 is configured to have a plate-shaped elastic member ("elastic blade") 1 (FIG. 5) formed of an elastic material, and a supporting plate 2 (FIG. 5) as a supporting member that supports the elastic member. In this embodiment, the elastic blade 1 of the photosensitive member cleaning blade 108 is a plate-like member that is generally rectangular in plan view and has a predetermined length and a predetermined thickness in the longitudinal direction (almost parallel in this embodiment) that is arranged along the direction (width direction) that is generally perpendicular to the moving direction of the surface of the photosensitive drum 103, and in the lateral direction that intersects (almost perpendicular to) the longitudinal direction. In this embodiment, for example, urethane rubber with a hardness of 77° (JIS-A) and a thickness of 2 mm is used as the material of the elastic blade 1. A part of the surface of the elastic blade 1 on the side opposite to the photosensitive drum 103 side at the base end side, which is one end in the lateral direction, is overlapped on the support plate 2 along the longitudinal direction, and in this embodiment, is fixed to the support plate 2 by adhesion. The free end of the elastic blade 1, which is the other end in the lateral direction, faces the upstream side in the moving direction of the surface of the photosensitive drum 103, and the edge of the free end is abutted against the surface of the photosensitive drum 103. In this embodiment, the elastic blade 1 of the photosensitive drum cleaning blade 108 is brought into contact with the photosensitive drum 103 at a contact angle of 22° and a linear pressure of 30 N / m. This contact angle is the angle that the surface of the elastic blade 1 near the edge portion on the photosensitive drum 103 side forms with the tangent to the photosensitive drum 103 at the contact portion between the elastic blade 1 and the photosensitive drum 103.Moreover, this linear pressure is an average value over the entire area of ​​the elastic blade 1 in the longitudinal direction.

[0030] Toner remaining on the intermediate transfer belt 101 after the secondary transfer (secondary transfer residual toner) is removed from the surface of the intermediate transfer belt 101 and collected by an intermediate transfer body cleaning device 120 serving as an intermediate transfer body cleaning means. In this embodiment, the intermediate transfer body cleaning device 120 is a counter type blade cleaning device. The intermediate transfer body cleaning device 120 has an intermediate transfer body cleaning container 121 and an intermediate transfer body cleaning blade 102 serving as a cleaning member. The intermediate transfer body cleaning blade 102 abuts against the outer surface of the intermediate transfer belt 101, the inner surface of which is supported by a tension roller 115. That is, the intermediate transfer body cleaning blade 102 abuts against the outer surface of the intermediate transfer belt 101 downstream of the secondary transfer portion T2 and upstream of the most upstream primary transfer portion T1Y in the moving direction of the surface of the intermediate transfer belt 101. In other words, the secondary transfer roller 111 contacts the outer surface of the intermediate transfer belt 101 downstream of the most downstream primary transfer portion T1K and upstream of the intermediate transfer body cleaning blade 102 in the moving direction of the surface of the intermediate transfer belt 101 (the transport direction of the toner image). The intermediate transfer body cleaning blade 102 contacts the surface of the intermediate transfer belt 101 so as to face the moving direction of the surface of the intermediate transfer belt 101. The intermediate transfer belt cleaning blade 102 scrapes off the secondary transfer residual toner from the surface of the rotating intermediate transfer belt 101 and collects it in the intermediate transfer body cleaning container 121. The intermediate transfer body cleaning blade 102 is configured to have a plate-shaped elastic member ("elastic blade") 1 (FIG. 5) made of an elastic material and a supporting plate 2 (FIG. 5) serving as a supporting member for supporting the elastic member. In this embodiment, the elastic blade 1 of the intermediate transfer member cleaning blade 102 is a flat member that is generally rectangular in plan view and has a predetermined length and thickness in the longitudinal direction that is arranged along (approximately parallel in this embodiment) a direction (width direction) that is generally perpendicular to the moving direction of the surface of the intermediate transfer belt 101, and in the lateral direction that intersects (approximately perpendicular to) the longitudinal direction. In this embodiment, the material of this elastic blade 1 is, for example, urethane rubber with a hardness of 77° (JIS-A) and a thickness of 2 mm.A part of the surface of the elastic blade 1 opposite to the intermediate transfer belt 101 side at the base end side, which is one end in the short side direction, is overlapped with the support plate 2 along the long side direction, and in this embodiment, is fixed to the support plate 2 by adhesion. The other end of the elastic blade 1 in the short side direction, which is the free end, faces the upstream side in the moving direction of the surface of the intermediate transfer belt 101, and the edge of the free end is abutted against the surface of the intermediate transfer belt 101. In this embodiment, the elastic blade 1 of the intermediate transfer member cleaning blade 102 is abutted against the intermediate transfer belt 101 at an abutment angle of 25° with respect to the intermediate transfer belt 101 and a linear pressure of 35 N / m. This abutment angle is the angle that the surface of the elastic blade 1 near the edge portion on the intermediate transfer belt 101 side forms with the tangent of the intermediate transfer belt 101 at the abutment portion between the elastic blade 1 and the intermediate transfer belt 101. This linear pressure is the average value of the elastic blade 1 over the entire area in the long side direction.

[0031] 2.Explanation of blade curl FIG. 2 is an explanatory diagram of the arrangement (herein, simply referred to as "longitudinal arrangement") of the main elements of the image forming apparatus 100 in a direction (herein, simply referred to as "longitudinal direction") substantially perpendicular to the process direction (the direction of movement of the surfaces of the photosensitive drum 103 and the intermediate transfer belt 101). In FIG. 2, the length (herein, simply referred to as "longitudinal width") of each element in the longitudinal direction is the length of the following regions. The longitudinal width of the developing device 106 is the width in the longitudinal direction in which the developing device 106 can supply the developer. That is, it is the width of the region in which the developing sleeve 161 can carry the developer (the width coated with the developer). This longitudinal width region of the developing device 106 is also referred to as the "developing region". In addition, the longitudinal width of the toner image forming region (image forming region) is the width (maximum image formable width) of the "toner image forming region" in which the exposure device 105 can form an electrostatic image by performing laser exposure to form a toner image in the longitudinal direction. The longitudinal width of the photoreceptor cleaning blade 108 refers to the width of the elastic blade 1 (the contact portion between the elastic blade 1 and the photoreceptor drum 103) of the photoreceptor cleaning blade 108 in the longitudinal direction. The region of the longitudinal width of the photoreceptor cleaning blade 108 is also called the "photoreceptor cleaning region" or simply the "cleaning region". The longitudinal width of the intermediate transfer member cleaning blade 102 refers to the width of the elastic blade 1 (the contact portion between the elastic blade 1 and the intermediate transfer belt 101) of the intermediate transfer member cleaning blade 102 in the longitudinal direction. The region of the longitudinal width of the intermediate transfer member cleaning blade 102 is also called the "intermediate transfer member cleaning region" or simply the "cleaning region". In this embodiment, the above elements are aligned with a central reference so that the approximate centers of the longitudinal direction are aligned. Therefore, in this embodiment, the positional relationship between both ends of the above elements in the longitudinal direction is approximately symmetrical with respect to the approximate center of the longitudinal direction. In this embodiment, the relatively smaller longitudinal width between each of the above elements is arranged to be contained inside the relatively larger longitudinal width.

[0032] In consideration of the stability of development at the longitudinal ends, the longitudinal width of the development region is set to be larger than the longitudinal width of the toner image forming region. Also, in order to be able to clean toner scattered from the longitudinal ends of the developing device 106, the longitudinal width of the photoconductor cleaning region is set to be larger than the longitudinal width of the development region. Furthermore, in order to be able to clean the toner on the intermediate transfer belt 101 even if the intermediate transfer belt 101 is misaligned in the longitudinal direction due to meandering, the longitudinal width of the intermediate transfer belt cleaning region is set to be larger than the longitudinal width of the photoconductor cleaning region.

[0033] In the case of such a longitudinal arrangement, there are areas near the longitudinal ends of the photoreceptor cleaning blade 108 and the intermediate transfer body cleaning blade 102 where little toner or external additives serving as lubricants are supplied. In these areas, the coefficient of friction between the elastic blade 1 of the photoreceptor cleaning blade 108 and the photoreceptor drum 103, and the coefficient of friction between the elastic blade 1 of the intermediate transfer body cleaning blade 102 and the intermediate transfer belt 101 become high. In this embodiment, the areas outside the development area in each of the photoreceptor cleaning area and the intermediate transfer body cleaning area are called "high μ areas".

[0034] FIG. 3 is a schematic diagram of a conventional cleaning blade 200. FIG. 3(a) is a schematic plan view seen from the side opposite to the surface to be cleaned (the surface of the photosensitive drum 103, the surface of the intermediate transfer belt 101). FIG. 3(b) is a schematic perspective view seen from the tip side that contacts the surface to be cleaned. The conventional cleaning blade 200 is configured to have an elastic blade 201 and a supporting metal plate 202. In the conventional cleaning blade 200, the free length of the elastic blade 201 is set to be approximately uniform in the longitudinal direction of the elastic blade 201. The "free length" of the elastic blade refers to the length in the short side direction of the part protruding from a supporting member or a restricting member that restricts deformation of the free end side of the elastic blade provided in contact with or facing the surface of the elastic blade. In this example, the free length of the elastic blade 201 is the length from the adhesive surface between the elastic blade 201 and the supporting metal plate 202 to the free end of the elastic blade 201. That is, in this example, the supporting metal plate 202 constitutes a restricting portion that restricts the free length of the elastic blade 201 .

[0035] 4 is a schematic diagram showing the deformation state of a conventional cleaning blade 200 in a high μ region. In the high μ region, the load on the elastic blade 201 is large. Therefore, in the high μ region, the edge of the elastic blade 201 is pulled significantly downstream in the moving direction of the surface of the image carrier due to the rotation of the image carrier such as the photosensitive drum 103 or the intermediate transfer belt 101. This is the cause of the blade curling. Therefore, if the load in the high μ region can be relieved, the occurrence of the blade curling can be suppressed.

[0036] FIG. 5 is a schematic diagram of the photoconductor cleaning blade 108 and the intermediate transfer body cleaning blade 102 of this embodiment. In this embodiment, the photoconductor cleaning blade 108 and the intermediate transfer body cleaning blade 102 may have different settings such as the longitudinal width of the cleaning area, but the overall configuration is substantially the same. Therefore, the photoconductor cleaning blade 108 and the intermediate transfer body cleaning blade 102 may be collectively referred to simply as "cleaning blade 3". FIG. 5(a) is a schematic plan view of the cleaning blade 3 as viewed from the side opposite to the surface to be cleaned (the surface of the photoconductor drum 103, the surface of the intermediate transfer belt 101). FIG. 5(b) is a schematic perspective view of the cleaning blade 3 as viewed from the tip side that contacts the surface to be cleaned.

[0037] The cleaning blade 3 of this embodiment is configured to have an elastic blade 1 and a supporting plate 2. In the cleaning blade 3 of this embodiment, the free length of the elastic blade 1 is changed in the longitudinal direction of the elastic blade 1 depending on the shape of the supporting plate 2. In this embodiment, the free length of the elastic blade 1 is the length from the adhesive surface between the elastic blade 1 and the supporting plate 2 to the free end of the elastic blade 1. In other words, in this embodiment, the supporting plate 2 constitutes a regulating portion that regulates the free length of the elastic blade 1. Here, from the viewpoint of cleaning performance, etc., it is desired that the tip (free end) of the elastic blade 1 extends along a direction that is approximately perpendicular to the moving direction of the surface of the image carrier such as the photosensitive drum 103 or the intermediate transfer belt 101 (approximately parallel in this embodiment). Therefore, in this embodiment, the free length of the elastic blade 1 is changed depending on the shape of the supporting plate 2.

[0038] Specifically, in this embodiment, the free length L1 at the central portion in the longitudinal direction of the elastic blade 1 and the free length L2 in the region of a predetermined width (longitudinal width) w at the end portion in the longitudinal direction are set to satisfy the relationship L1 < L2. And in this embodiment, this width w is set to be the same as or larger than the width (longitudinal width) of the high-μ region. Thereby, the load applied to the elastic blade 1 in the high-μ region can be released. Note that in this embodiment, the region of width w where the free length of the elastic blade 1 is L2 is also referred to as the "long free length region". Also, in this embodiment, the region where the free length of the elastic blade 1 is L1 is also referred to as the "short free length region". Also, in order to release the load more effectively, it is desirable to set the free length L1 and the free length L2 to satisfy the relationship 1.2×L1 ≤ L2. However, typically, the free length L1 and the free length L2 are set to satisfy the relationship L2 ≤ 1.46×L1. Note that the shape of the support sheet metal 2 is not limited to the shape shown in FIG. 5.

[0039] FIG. 6 is a schematic diagram showing the deformed state in the high-μ region of the cleaning blade 3 of this embodiment. By increasing the free length of the elastic blade 1 in the high-μ region, the load applied to the elastic blade 1 can be released. Therefore, the occurrence of blade curling is suppressed without the edge portion of the elastic blade 1 being largely drawn downstream in the moving direction of the surface of the image carrier such as the photosensitive drum 103 or the intermediate transfer belt 101.

[0040] However, when the free length of the elastic blade 1 is set to be long, the contact pressure of the elastic blade 1 against the image carrier such as the photosensitive drum 103 or the intermediate transfer belt 101 decreases. Therefore, when the width w is large toward the inside of the toner image forming region, there is a possibility of cleaning failure depending on the formed image or the like. Therefore, it is desirable to set the width w to be the same as or larger than the width of the high-μ region and not to enter the inside of the toner image forming region.

[0041] FIG. 7 is an explanatory diagram of the longitudinal width of each part of the cleaning blade 3 of this embodiment. The top and bottom parts of FIG. 7 are schematic plan views of the cleaning blade 3 as seen from the side of the surface to be cleaned (the surface of the photosensitive drum 103, the surface of the intermediate transfer belt 101), and schematic plan views of the cleaning blade 3 as seen from the side opposite the side of the surface to be cleaned (the surface of the photosensitive drum 103, the surface of the intermediate transfer belt 101). Here, the free length at the longitudinal center of the elastic blade 1 is L1, and the free length at the longitudinal end of the elastic blade 1 in a region of a given width w (long free length region) is L2. In this embodiment, the following equation is used: L1 <L2 The following relationship is satisfied. 1.2×L1≦L2 It is desirable to satisfy the following relationship.

[0042] The longitudinal width of the elastic blade 1 (cleaning region) is w1, the longitudinal width of the development region is w2, and the longitudinal width of the toner image forming region is w3. For convenience, the regions themselves having the longitudinal widths w, w1, w2, and w3 may be referred to by the symbols w, w1, w2, and w3. In this case, the following formula is satisfied: w ≥ (w1-w2) / 2 It is desirable to satisfy the following relationship.

[0043] In addition, the following formula: w≦(w1-w3) / 2 It is desirable to satisfy the following relationship.

[0044] From these, the following formula, (w1-w2) / 2≦w≦(w1-w3) / 2 It is desirable to satisfy the following relationship.

[0045] In this embodiment, since each element is aligned with the center as described above, the relationship of the above formula is satisfied, but the following may be done at each of the longitudinal ends of the cleaning blade 3. That is, in the longitudinal direction, it is desirable that the inner end of the long free length region w is located at the same position as the end of the development region w2 or on the inside, and at the same position as the end of the toner image forming region w3 or on the outside. In addition, in the longitudinal direction, it is desirable that the end of the short free length region w5 is located at the same position as the end of the toner image forming region w3 or on the outside, and at the same position as the end of the development region w2 or on the inside. In this embodiment, a long free length region w having a substantially uniform free length of L2 in the longitudinal direction is provided. In this embodiment, in the longitudinal direction, the inner end of this long free length region w is located on the inside of the end of the development region w2 and on the outside of the end of the toner image forming region w3. This long free length region w includes the end of the elastic blade 1. In this embodiment, a short free length region w5 is provided with a substantially uniform free length L1 in the longitudinal direction. In this embodiment, the end of the short free length region w5 is located outside the end of the toner image forming region w3 and inside the end of the development region w2 in the longitudinal direction. The short free length region w5 includes the center of the elastic blade 1. In this embodiment, the long free length region w and the short free length region w5 are connected via a region in which the free length changes substantially linearly. However, the long free length region w and the short free length region w5 may be directly connected via a step in the free length.

[0046] 3. Experimental Example 3-1. Experimental Example 1 A plurality of cleaning blades 3 with different widths w were prepared in the configuration of FIG. 5 (common configuration to this embodiment), and were mounted on the image forming apparatus 100 as the photoconductor cleaning blade 108 to carry out a continuous paper feed test to confirm the effect of this embodiment. A solid white image, which is likely to cause blade curling, was used as the image to be output in the continuous paper feed test. In addition, in the configuration of this embodiment, the width of the high μ region of the photoconductor cleaning blade 108 is 4 mm, and the length in the longitudinal direction from the end (extreme end) of the elastic blade 1 to the outer end of the toner image forming region is 8 mm. In addition, the free length L1 is set to 8 mm, and the free length L2 is set to 9.6 mm, and the relationship between the free length L1 and the free amount L2 is set to 1.2×L1≦L2. In the continuous paper feed test, the presence or absence of blade curling due to an increase in the number of sheets fed was confirmed. In addition, a predetermined test image was formed in the middle of the continuous paper feed test to confirm the presence or absence of cleaning defects (toner slip-through).

[0047] The results of this continuous paper feed test are shown in FIG. 8. FIG. 8(a) is a table showing the occurrence of blade curling in the continuous paper feed test. FIG. 8(b) is a table showing the occurrence of cleaning failures in the continuous paper feed test. As shown in FIG. 8(a), when the width w was 0 mm, 2 mm, and 4 mm, blade curling occurred during the continuous paper feed test. On the other hand, when the width w was 6 mm, 8 mm, and 10 mm, the continuous paper feed test was completed without blade curling. Also, as shown in FIG. 8(b), when the width w was 0 mm, 2 mm, 4 mm, and 6 mm, no cleaning failure occurred during the continuous paper feed test. On the other hand, when the width w was 8 mm, a minor cleaning failure occurred during the continuous paper feed test, and when the width w was 10 mm, a cleaning failure occurred during the continuous paper feed test.

[0048] In this way, in the photoconductor cleaning blade 108 of the configuration shown in Figure 5, by making the width w larger than the width of the high μ region and setting it so that it does not overlap the toner image forming region, it is possible to more effectively prevent blade curling while suppressing the occurrence of cleaning failures.

[0049] 3-2. Experimental Example 2 A plurality of cleaning blades 3 with different widths w were prepared in the configuration of FIG. 5 (common configuration to this embodiment), and were mounted on the image forming apparatus 100 as the intermediate transfer member cleaning blade 102 to carry out a continuous paper feed test to confirm the effect of this embodiment. A solid white image, which is likely to cause blade curling, was used as the image to be output in the continuous paper feed test. In addition, in the configuration of this embodiment, the width of the high μ region of the intermediate transfer member cleaning blade 102 is 6 mm, and the length in the longitudinal direction from the end (extreme end) of the elastic blade 1 to the outer end of the toner image forming region is 10 mm. In addition, the free length L1 is set to 8 mm, and the free length L2 is set to 9.6 mm, and the relationship between the free length L1 and the free amount L2 is set to 1.2×L1≦L2. In the continuous paper feed test, the presence or absence of blade curling due to an increase in the number of sheets passed was confirmed. In addition, a predetermined test image was formed in the middle of the continuous paper feed test to confirm the presence or absence of cleaning defects (toner slip-through).

[0050] The results of this continuous paper feed test are shown in FIG. 9. FIG. 9(a) is a table showing the occurrence of blade curling during the continuous paper feed test. FIG. 9(b) is a table showing the occurrence of cleaning failures during the continuous paper feed test. As shown in FIG. 9(a), when the width w was 0 mm, 2 mm, 4 mm, and 6 mm, blade curling occurred during the continuous paper feed test. On the other hand, when the width w was 8 mm and 10 mm, the continuous paper feed test was completed without blade curling. Also, as shown in FIG. 9(b), when the width w was 0 mm, 2 mm, 4 mm, 6 mm, and 8 mm, no cleaning failure occurred during the continuous paper feed test. On the other hand, when the width w was 10 mm, a minor cleaning failure occurred during the continuous paper feed test.

[0051] In this manner, in the intermediate transfer member cleaning blade 102 of the configuration shown in FIG. 5, by making the width w larger than the width of the high μ region and setting it so as not to overlap the toner image forming region, it is possible to more effectively suppress blade curling while also suppressing the occurrence of cleaning failures.

[0052] 3-3.Experimental Example 3 A continuous paper feed test was carried out in the same manner as in Experimental Example 1, except that the free length L2 was set to 9.0 mm and the relationship between the free length L1 and the free amount L2 was set to 1.2×L1>L2. In the continuous paper feed test, the occurrence of blade curling due to an increase in the number of sheets fed was confirmed.

[0053] The results of this continuous paper feed test are shown in Figure 10. Figure 10 is a table showing the occurrence of blade curl during the continuous paper feed test. As shown in Figure 10, blade curl occurred during the continuous paper feed test in all cases where the width w was 0 mm, 2 mm, 4 mm, 6 mm, 8 mm, and 10 mm. This is thought to be because the load could not be sufficiently released.

[0054] 4. Modifications A preferred embodiment of the cleaning blade 3 of this embodiment has been described with reference to FIG. 7 and other figures. As shown in FIG. 7, it is important for the free length to change sharply from the free length L2 in the high μ region to the free length L1 in the toner image forming region in order to suppress blade curling and to suppress the occurrence of cleaning defects. However, this embodiment is not limited to the way in which the free length of the elastic blade changes as shown in FIG. 7. As will be described later, it has been found that the same effect as described above can be obtained by setting the free lengths L1 and L2 as follows.

[0055] Let the average value of the free length L1 of the elastic blade 1 in the toner image formation region be the average free length L1a. Also, let the average value of the free length L2 of the elastic blade 1 in the high-μ region (outside the development region) be the average free length L2a. At this time, similar to the above, the average free length L1a and the average free length L2a are set so as to satisfy the relationship L1a < L2a. Also, similar to the above, it is desirable that the average free length L1a and the average free length L2a satisfy the relationship 1.2×L1a ≤ L2a. Also, it can be said that it is desirable that they satisfy the relationship L2a ≤ 1.46×L1a. Here, let the difference (absolute value) between the average free length L1a and the average free length L2a be the free length difference ΔL. At this time, the upper limit value of the free length L1 of the elastic blade 1 in the toner image formation region is desirably "average free length L1a + free length difference ΔL × 20%". That is, the free length L1 of the elastic blade 1 in the toner image formation region is desirably "average free length L1a + free length difference ΔL × 20%" or less. Also, the lower limit value of the free length L2 in the high-μ region is desirably "average free length L2a - free length difference ΔL × 20%". That is, the free length L2 of the elastic blade 1 in the high-μ region is desirably "average free length L2a - free length difference ΔL × 20%" or more. Also, the upper limit value of the free length L2 in the high-μ region is desirably "average free length L2a + free length difference ΔL × 130%". That is, the free length L2 of the elastic blade 1 in the high-μ region is desirably "average free length L2a + free length difference ΔL × 130%" or less. Also, let the free length of the elastic blade 1 in the region inside the development region and outside the toner image formation region (the overlapping region which is a non-image formation region where the overlapping toner from the developing device 106 can adhere) be L3. At this time, it is desirable that the free length L3 is between the average free length L1a and the average free length L2a. That is, it is desirable to satisfy the relationship average free length L1a ≤ free length L3 ≤ average free length L2a.

[0056] 11 is an explanatory diagram for explaining the setting of the free length of the elastic blade 1, where the upper part shows the relationship between the longitudinal width of each part, and the lower part shows the relationship between the longitudinal position and the free length of the elastic blade 1. Considering the relationship with the above-mentioned free length difference ΔL, the free length L2 of the elastic blade 1 in the high μ region is expressed by the following formula: L2a ≥ 1.2 × L1a L2≧1.16×L1a (i.e., L2≧L2a-ΔL×0.2) L2≦1.46×L1a (i.e., L2≦L2a+ΔL×1.3) It is desirable to satisfy the above. If the maximum value of this range is exceeded, toner may slip through (cleaning failure). Also, if the minimum value of this range is exceeded, blade curling may occur.

[0057] In addition, taking into consideration the relationship with the above-mentioned free length difference ΔL, the free length L1 of the elastic blade 1 in the toner image forming area is expressed by the following formula: L1≦1.06×L1a (i.e., L1≦L1a+ΔL×0.2) It is desirable to satisfy the following. If the maximum value in this range is exceeded, there is a possibility that toner may slip through (cleaning failure).

[0058] As described above, the free length L3 of the elastic blade 1 in the region (fogging region) inside the development region and outside the toner image forming region is expressed by the following formula: L1a≦L3≦L2a It is desirable to satisfy the following: This allows the free length of the elastic blade 1 to change abruptly from the free length L2 in the high μ region to the free length L2 in the toner image forming region, and effectively suppresses blade curling and cleaning defects.

[0059] Fig. 12 shows the results of a continuous paper feed test similar to that described above, using a cleaning blade 3 with an average free length L1a = 8 mm, an average free length L2a = 9.6 mm, and a width w = 6 mm, in which the maximum value of free length L1, the minimum value of free length L2, and the maximum value are changed as shown in Fig. 11. Fig. 12(a) shows the occurrence of blade curling, and Fig. 12(b) shows the occurrence of toner slip-through (cleaning failure). Here, the results of a test using an image forming apparatus 100 equipped with the cleaning blade 3 as a photoconductor cleaning blade 108 are shown as a representative example. The results of a test using an image forming apparatus 100 equipped with a similar cleaning blade 3 as an intermediate transfer body cleaning blade 102 are also similar.

[0060] From FIG. 12, it can be seen that by setting the free lengths L1 and L2 as described above in consideration of the relationship with the free length difference ΔL, it is possible to suppress blade curling and the occurrence of poor cleaning.

[0061] As described above, according to this embodiment, it is possible to suppress the occurrence of cleaning defects while suppressing the blade curling.

[0062] [Example 2] Next, another embodiment of the present invention will be described. The basic configuration and operation of the image forming apparatus of this embodiment are the same as those of embodiment 1. Therefore, in the image forming apparatus of this embodiment, elements having the same or corresponding functions or configurations as those of the image forming apparatus of embodiment 1 are given the same reference numerals as those of the image forming apparatus of embodiment 1, and detailed explanations are omitted.

[0063] Fig. 13 is a schematic diagram of the cleaning blade 3 (photosensitive member cleaning blade 108, intermediate transfer member cleaning blade 102) of this embodiment. Fig. 13(a) is a schematic plan view of the cleaning blade 3 as viewed from the side opposite to the surface to be cleaned (surface of the photosensitive drum 103, surface of the intermediate transfer belt 101). Fig. 13(b) is a schematic perspective view of the cleaning blade 3 as viewed from the tip side that contacts the surface to be cleaned. The cleaning blade 3 of this embodiment is a type of cleaning blade in which the free length of the elastic blade is regulated by using a back plate metal.

[0064] The cleaning blade 3 of this embodiment is configured to include an elastic blade 11, a support metal plate 12 as a support member, a back metal plate 13 as a regulating member, and a spacer member 14 as a fixing member for fixing the back metal plate 13 to the support metal plate 2. In the cleaning blade 3 of this embodiment, the elastic blade 11 is fixed to the support metal plate 12 by adhesion, but a part of the surface facing the image carrier such as the photosensitive drum 103 or the intermediate transfer belt 101 is adhered to the support metal plate 12. In addition, in the cleaning blade 3 of this embodiment, the free length of the elastic blade 11 is regulated by the back metal plate 13 that is superimposed on the surface of the elastic blade 11 from the side opposite to the support metal plate 12. That is, in this embodiment, the back metal plate 13 constitutes a regulating portion that regulates the free length of the elastic blade 11. The back metal plate 13 is held at a predetermined distance from the elastic blade 11 by the spacer member 14. In this embodiment, the free length of elastic blade 11 can be changed in the longitudinal direction of elastic blade 11 by changing the shape of back plate metal 13. In this embodiment, the free length of elastic blade 11 is the length in the lateral direction of the part of elastic blade 11 that protrudes from the overlapping part between elastic blade 11 and back plate metal 13 when viewed in the thickness direction of elastic blade 11.

[0065] As described above, the present invention is also applicable to the cleaning blade 3 having the configuration as in this embodiment, and the same effects as those in the configuration of the first embodiment can be obtained.

[0066] [Example 3] Next, another embodiment of the present invention will be described. The basic configuration and operation of the image forming apparatus of this embodiment are the same as those of embodiment 1. Therefore, in the image forming apparatus of this embodiment, elements having the same or corresponding functions or configurations as those of the image forming apparatus of embodiment 1 are given the same reference numerals as those of the image forming apparatus of embodiment 1, and detailed explanations are omitted.

[0067] Fig. 14 is a schematic diagram of the cleaning blade 3 (photoconductor cleaning blade 108, intermediate transfer belt cleaning blade 102) in this embodiment. Fig. 14(a) is a schematic side view of the cleaning blade 3 viewed along the longitudinal direction. Fig. 14(b) is a schematic plan view of the cleaning blade 3 viewed from the side of the surface to be cleaned (the surface of the photoconductor drum 103, the surface of the intermediate transfer belt 101).

[0068] In this example, a cleaning blade 3 having the configuration shown in Fig. 5 and Fig. 7 in Example 1 was used, and further, in order to impart resistance to blade curling to the elastic blade 1, a hardening treatment was performed on the elastic blade 1 as shown in Fig. 14(a) and (b). In this example, as shown in Fig. 14(a) and (b), both ends in the longitudinal direction of the elastic blade 1 were impregnated with an isocyanate compound and hardened. As a method for forming the processed portions 1a (hardening processed portion, isocyanate processed portion) on both ends in the longitudinal direction of the elastic blade 1, for example, a method having the following steps can be mentioned. (1) A step of contacting both longitudinal ends of the elastic blade 1 at a contact portion with an image carrier such as the photosensitive drum 103 or the intermediate transfer belt 101 with an isocyanate compound; (2) A step of impregnating the elastic blade 1 with the isocyanate compound by leaving the isocyanate compound in contact with the surface of the elastic blade 1; (3) removing the isocyanate compound remaining on the surface of the elastic blade 1 after the impregnation; and (4) A step of forming a treated portion by reacting the isocyanate compound impregnated in the elastic blade 1.

[0069] That is, in steps (1) and (2), an appropriate amount of isocyanate compound is impregnated into both longitudinal ends of the side surface 1x, which is the contact surface of the tip of the elastic blade 1 with an image carrier such as the photosensitive drum 103 or the intermediate transfer belt 101. The side surface 1x is the surface of the elastic blade 1 formed by the longitudinal and lateral directions on the image carrier side such as the photosensitive drum 103 or the intermediate transfer belt 101. In step (3), excess isocyanate compound is removed from the surface of the elastic blade 1, and in step (4), the isocyanate compound is reacted to form a processing portion (hardening processing portion, isocyanate processing portion) 1a. In step (4), it is considered that the polyurethane resin forming the elastic blade 1 reacts with the isocyanate compound to form an allophanate bond, which is hardened to form a high-hardness processing portion 1a. The processing portion 1a is provided on one end side and the other end side of the elastic blade 1 in the longitudinal direction. That is, urethane bonds having active hydrogen are present in the polyurethane resin forming the elastic blade 1. In step (4), the urethane bond reacts with the impregnated isocyanate compound to form an allophanate bond, forming the treated portion 1a. The isocyanate compound is impregnated into the elastic blade 1 to a depth of 100 μm to 500 μm. In addition, a polymerization reaction (e.g., carbodiimide reaction, isocyanurate reaction, etc.) caused by a reaction between the isocyanate compounds also proceeds at the same time, which is considered to contribute to the formation of the treated portion 1a. As a result, the hardness of the treated portion 1a is improved, the friction coefficient of the elastic blade 1 against the surface to be cleaned is reduced, and blade curling can be suppressed. The dynamic hardness of the treated portion 1a is preferably 0.17 mN / (μm×μm) or more from the viewpoint of suppressing blade curling. The dynamic hardness can be measured by using a dynamic ultra-micro hardness tester manufactured by Shimadzu Corporation as a measuring instrument.

[0070] In this embodiment, the isocyanate compound to be impregnated into the elastic blade 1 may be an isocyanate compound having one isocyanate group in the molecule, or an isocyanate compound having two or more isocyanate groups in the molecule. Examples of the isocyanate compound having one isocyanate group in the molecule include aliphatic monoisocyanates such as octadecyl isocyanate (ODI), aromatic monoisocyanates, etc. In addition, examples of the isocyanate compound having two isocyanate groups in the molecule to be impregnated into the elastic blade 1 include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate (MDI), m-phenylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, etc. In this embodiment, in order to promote the reaction of the isocyanate compound, a catalyst may also be impregnated into the polyurethane resin in addition to the isocyanate compound.

[0071] The isocyanate compound can be impregnated into the elastic blade 1 by, for example, impregnating a fibrous or porous member with the isocyanate compound and applying it to the elastic blade 1, or by applying it by spraying. In this manner, the isocyanate compound is impregnated into the elastic blade 1 for a predetermined time. The treatment time can be changed depending on the configuration of the image forming apparatus 100 and the member with which the elastic blade 1 comes into contact, and the photoconductor cleaning blade 108 and the intermediate transfer member cleaning blade 102 may each have an optimal treatment time and treatment width.

[0072] In step (3), the isocyanate compound remaining on the surface of the elastic blade 1 is wiped off with a solvent capable of dissolving the isocyanate compound. After the above steps, in step (4), the impregnated isocyanate compound reacts to form allophanate bonds or is almost entirely consumed by reaction with moisture in the air, forming a white, opaque, highly hard treated layer.

[0073] The processed portion 1a produced by the above-mentioned process may swell in the thickness direction of the elastic blade 1. The swelling of the processed portion 1a may cause a step at the boundary between the processed portion 1a and the surface layer at the center side that has not been subjected to the isocyanate treatment, and there is a risk that the toner may slip through the step. Therefore, it is desirable to set the coating conditions so that the step is suppressed as much as possible. Note that if the boundary step, i.e., the difference in thickness of the elastic blade 1, is, for example, 12 μm or less, the toner can be effectively suppressed from slipping through, and it is more preferable that it is 10 μm or less.

[0074] In this embodiment, the isocyanate-treated surface is the side surface 1x, but the same effect can be obtained by swelling in the free length direction with the end surface 1y treated as the treated surface. The end surface 1y is the tip surface of the surface formed by the thickness direction and the longitudinal direction of the elastic blade 1 that abuts against the image carrier such as the photosensitive drum 103 or the intermediate transfer belt 101.

[0075] Here, a plurality of cleaning blades 3 were created in the configuration of FIG. 14 (common configuration with this embodiment) with different widths (longitudinal width) w4 of the processing portion 1a of the elastic blade 1 and different widths w of the region (long free length region) with a free length of L2. Then, the cleaning blade 3 was mounted on the image forming apparatus 100 as the photoreceptor cleaning blade 108, and a continuous paper feed test was performed to confirm the effect of this embodiment. A solid white image that is likely to cause blade curling was used as the image to be output in the continuous paper feed test. In addition, in the configuration of this embodiment, the photoreceptor cleaning blade 108 has a width of 4 mm in the high μ region, and a length from the end (extreme end) of the elastic blade 1 in the longitudinal direction to the outer end of the toner image forming region is 8 mm. In addition, the free length L1 was set to 8 mm, and the free length L2 was set to 9.6 mm. Furthermore, in order to confirm the effect against blade curling as a more severe condition, the contact angle of the photoreceptor cleaning blade 108 with the photoreceptor drum 103 was set to 25°. The width w4 is the width of the isocyanate-treated region on the ridge formed by the side surface 1x and the end surface 1y of the elastic blade 1. In the continuous paper-passing test, the occurrence of blade curling due to an increase in the number of sheets passed was confirmed. In addition, during the continuous paper-passing test, a specified test image was formed to confirm the occurrence of cleaning failure (toner slip-through). In addition, during the continuous paper-passing test, the occurrence of local abrasion in the area corresponding to the processing portion 1a on the surface of the photosensitive drum 103 was confirmed.

[0076] Fig. 15 is an explanatory diagram of the longitudinal widths of each part of the cleaning blade 3 of this embodiment. The top and bottom of Fig. 15 are schematic plan views of the cleaning blade 3 as seen from the side of the surface to be cleaned (the surface of the photosensitive drum 103, the surface of the intermediate transfer belt 101), and schematic plan views of the cleaning blade 3 as seen from the opposite side to the side of the surface to be cleaned (the surface of the photosensitive drum 103, the surface of the intermediate transfer belt 101), respectively. Fig. 15 shows the relationship between the longitudinal width w1 of the elastic blade 1 (cleaning region), the longitudinal width w2 of the development region, the longitudinal width w3 of the toner image forming region, and the width w4 of the processing portion 1a.

[0077] The results of this continuous paper feed test are shown in Figure 16. Figure 16(a) is a table showing the occurrence of blade curling in the continuous paper feed test. Figure 16(b) is a table showing the occurrence of cleaning defects in the continuous paper feed test. Figure 16(c) is a table showing the occurrence of localized abrasion at the longitudinal end of the photosensitive drum 103 in the continuous paper feed test.

[0078] As shown in FIG. 16(a), when the width w4 of the processing portion 1a is 0 mm, that is, when the hardening process is not performed, the following occurred. That is, when the width w is 0 mm, 2 mm, 4 mm, or 6 mm, the blade curl occurs during the continuous paper feed test, and when the width w is 8 mm or 11 mm, the continuous paper feed test is completed without the blade curl. When the width w4 of the processing portion 1a is 2 mm, the following occurred. That is, when the width w is 0 mm or 2 mm, the blade curl occurs during the continuous paper feed test, and when the width w is 4 mm, 6 mm, 8 mm, or 10 mm, the continuous paper feed test is completed without the blade curl. When the width w4 of the processing portion 1a is 4 mm, 6 mm, 8 mm, or 10 mm, the continuous paper feed test is completed without the blade curl in any of the widths w.

[0079] Also, as shown in FIG. 16(b), when the width w4 of the processing portion 1a was 0 mm, 2 mm, 4 mm, and 6 mm, the following occurred. That is, when the width w was 0 mm, 2 mm, 4 mm, and 6 mm, no cleaning failure occurred during the continuous paper feed test. When the width w was 8 mm, a minor cleaning failure occurred during the continuous paper feed test. When the width w was 10 mm, a cleaning failure occurred during the continuous paper feed test. When the width w4 of the processing portion 1a was 8 mm and 10 mm, the following occurred. That is, when the width w was 0 mm, 2 mm, 4 mm, 6 mm, and 8 mm, a minor cleaning failure occurred during the continuous paper feed test. When the width w was 10 mm, a cleaning failure occurred during the continuous paper feed test.

[0080] Also, as shown in FIG. 16(c), when the width w4 of the processing portion 1a was 0 mm or 2 mm, no local scraping occurred at the end of the longitudinal direction of the photosensitive drum 103 for any width w. When the width w4 of the processing portion 1a was 4 mm, the following occurred. That is, when the width w was 0 mm, 2 mm, or 4 mm, local scraping occurred at the end of the longitudinal direction of the photosensitive drum 103, and a vertical stripe-like image defect occurred. When the width w was 6 mm, 8 mm, or 10 mm, no local scraping occurred at the end of the longitudinal direction of the photosensitive drum 103. When the width w4 of the processing portion 1a was 6 mm, 8 mm, or 10 mm, local scraping occurred at the end of the longitudinal direction of the photosensitive drum 103, and a vertical stripe-like image defect occurred for any width w.

[0081] The phenomenon of the photosensitive drum 103 being locally scraped is believed to occur because, when the processing portion 1a is applied to the width w2 of the development area, the hardened elastic blade 1 polishes the photosensitive drum 103 with a higher contact pressure via the developer acting as an abrasive. As can be seen from the above results, by setting the processing portion 1a outside the width w2 of the development area, it is possible to suppress local scraping of the photosensitive drum 103. In addition, by setting the free length L2 of the range of the processing portion 1a to be larger than the free length L1 of the central portion to reduce the contact pressure, it is possible to more effectively suppress local scraping of the photosensitive drum 103.

[0082] As described above, in the case of the photoconductor cleaning blade 108, the setting of the width w4 of the processing portion 1a may result in excessive abrasion of the photoconductor drum 103 at the location facing the processing portion 1a at the longitudinal end of the elastic blade 1. Similarly, in the case of the intermediate transfer member cleaning blade 102, the setting of the width w4 of the processing portion 1a may result in a problem of abrasion of the intermediate transfer belt 101 at the location facing the processing portion 1a at the longitudinal end of the elastic blade 1. Therefore, by setting the width w4 of the processing portion 1a in the same manner as described above, it is possible to suppress local abrasion of the intermediate transfer belt 101.

[0083] As described above, regarding the setting of the width w4 of the processing unit 1a, the following can be said. That is, let the free length at the central portion in the longitudinal direction of the elastic blade 1 be L1, and the free length in a region of a predetermined width w (long free length region) at the end portion in the longitudinal direction of the elastic blade 1 be L2. At this time, the free lengths L1 and L2 are set so as to satisfy the relationship L1 < L2. Also, let the longitudinal width of the elastic blade 1 (cleaning region) be w1, the longitudinal width of the developing region be w2, the longitudinal width of the toner image forming region be w3, and the width of the processing unit 1a be w4. At this time, the following formula, w4 < (w1 - w2) / 2 is desirably set so as to satisfy the relationship. In this embodiment, since each element is aligned with respect to the central reference as described above, the relationship of the above formula is satisfied. However, at each of both end portions in the longitudinal direction of the cleaning blade 3, the following may be done. That is, in the longitudinal direction, the inner end portion of the processing unit 1a is positioned outside the end portion of the developing region w2. This processing unit 1a includes the outermost end portion of the elastic blade 1. Thereby, it is possible to suppress the occurrence of local wear at the longitudinal ends such as the photosensitive drum 103.

[0084] Also, considering the setting of the width w described in Example 1, the following formula, w4 < (w1 - w2) / 2 ≦ w ≦ (w1 - w3) / 2 is more desirably set so as to satisfy the relationship. Thereby, while effectively suppressing blade curling and cleaning failures, it is possible to suppress the occurrence of local wear at the longitudinal ends such as the photosensitive drum 103.

[0085] As described above, according to this embodiment, while effectively suppressing blade curling and cleaning failures, it is possible to suppress the occurrence of local wear at the longitudinal ends such as the photosensitive drum 103.

[0086] [Example 4] Next, another embodiment of the present invention will be described. The basic configuration and operation of the image forming apparatus of this embodiment are the same as those of embodiment 1. Therefore, in the image forming apparatus of this embodiment, elements having the same or corresponding functions or configurations as those of the image forming apparatus of embodiment 1 are given the same reference numerals as those of the image forming apparatus of embodiment 1, and detailed explanations are omitted.

[0087] In this embodiment, a modified example of the setting of the free length of the elastic blade 1 is described, taking into consideration the influence of discharge caused by the charging roller 104 and the secondary transfer roller 111 as contact members that contact the surface of the image carrier and are applied with a voltage.

[0088] 1. Explanation of blade curl FIG. 17 is an explanatory diagram of the longitudinal arrangement of the main elements of the image forming apparatus 100. FIG. 17(a) is an explanatory diagram of the longitudinal arrangement of the photoconductor cleaning blade 108, and FIG. 17(b) is an explanatory diagram of the longitudinal arrangement of the intermediate transfer member cleaning blade 102. The longitudinal width of the developing device 16, the longitudinal width of the photoconductor cleaning blade 108, and the longitudinal width of the intermediate transfer member cleaning blade 102 are the widths of the development area, the photoconductor cleaning area, and the intermediate transfer member cleaning area, respectively, as described in the first embodiment. The longitudinal width of the charging roller 104 is the width of the area in the longitudinal direction where the charging roller 104 can charge the photoconductor drum 103 (the contact area between the charging roller 104 and the photoconductor drum 103). The longitudinal width of the secondary transfer roller 111 is the width of the area in the longitudinal direction where the secondary transfer roller 111 can apply a voltage to the intermediate transfer belt 101 (the contact area between the secondary transfer roller 111 and the intermediate transfer belt 101). In this embodiment, the elements are aligned with respect to their centers so that their longitudinal centers are substantially aligned.

[0089] 17(a), the longitudinal width of the charging roller 104 is set to be larger than the longitudinal width of the development area in order to suppress adhesion of developer to the non-charged portion of the photosensitive drum 103. Also, the longitudinal width of the photosensitive member cleaning area is set to be larger than the longitudinal width of the charging roller 104 so that discharge products by the charging roller 104 can also be cleaned.

[0090] 17(b), the longitudinal width of the secondary transfer roller 111 is set larger than the longitudinal width of the development area so that the toner on the intermediate transfer belt 101 can be secondarily transferred even if longitudinal positional deviation occurs due to meandering of the intermediate transfer belt 101. Also, the longitudinal width of the intermediate transfer body cleaning area is set larger than the longitudinal width of the secondary transfer roller 111 so that discharge products by the secondary transfer roller 111 can also be cleaned.

[0091] In the case of such a longitudinal arrangement, the following regions exist near the longitudinal ends of the photoconductor cleaning blade 108 and the intermediate transfer body cleaning blade 102. That is, these are regions where little toner or external additives serving as lubricants are supplied and where the photoconductor cleaning blade 108 and the intermediate transfer body cleaning blade 102 are affected by discharges caused by the charging roller 104 and the secondary transfer roller 111. In these regions, the coefficient of friction between the photoconductor cleaning blade 108 and the elastic blade 1, and the coefficient of friction between the elastic blade 1 of the intermediate transfer body cleaning blade 102 and the intermediate transfer belt 101 become very high. In this embodiment, the region outside the development region in the photoconductor cleaning region and inside the longitudinal width of the charging roller 104, and the region outside the development region in the intermediate transfer body cleaning region and inside the longitudinal width of the secondary transfer roller 111 are called "high μ regions".

[0092] Fig. 18 is a schematic diagram showing the deformation state of the conventional cleaning blade 200 (Fig. 3) in the high μ region. In the high μ region, the load on the elastic blade 201 is large. Therefore, in the high μ region, the edge of the elastic blade 201 is pulled significantly downstream in the moving direction of the surface of the image carrier due to the rotation of the image carrier such as the photosensitive drum 103 or the intermediate transfer belt 101. This is the cause of the blade curling. Therefore, if the load in the high μ region can be relieved, the occurrence of the blade curling can be suppressed.

[0093] FIG. 19 is a schematic diagram of the photoconductor cleaning blade 108 and the intermediate transfer body cleaning blade 102 of this embodiment. In this embodiment, the photoconductor cleaning blade 108 and the intermediate transfer body cleaning blade 102 may differ in the longitudinal width of the cleaning area, but the overall configuration is substantially the same. Therefore, the photoconductor cleaning blade 108 and the intermediate transfer body cleaning blade 102 may be collectively referred to simply as "cleaning blade 3". FIG. 19(a) is a schematic plan view of the cleaning blade 3 as viewed from the side opposite to the surface to be cleaned (the surface of the photoconductor drum 103, the surface of the intermediate transfer belt 101). FIG. 19(b) is a schematic perspective view of the cleaning blade 3 as viewed from the tip side that contacts the surface to be cleaned.

[0094] The cleaning blade 3 of this embodiment is configured to include an elastic blade 1 and a support metal plate 2. In the cleaning blade 3 of this embodiment, the free length of the elastic blade 1 is changed in the longitudinal direction of the elastic blade 1 depending on the shape of the support metal plate 2. In this embodiment, the free length of the elastic blade 1 is the length from the adhesive surface between the elastic blade 1 and the support metal plate 2 to the free end of the elastic blade 1.

[0095] Specifically, in this embodiment, it is set as follows. That is, the free length in the first region with a predetermined width (longitudinal width) w11 including the central portion in the longitudinal direction of the elastic blade 1 is set as L11. Also, the free length in the third region with a predetermined width (longitudinal width) w13 including the end portion (the outermost end portion) in the longitudinal direction of the elastic blade 1 is set as L13. Further, the free length in the second region with a predetermined width (longitudinal width) w12 adjacent to the first region and the third region is set as L12. At this time, in this embodiment, the free lengths L11, L12, and L13 are set so as to satisfy the relationship L11 < L12 < L13. For convenience, the regions themselves of these widths w11, w12, and w13 may be referred to by attaching the symbols of w11, w12, and w13. In this embodiment, the free length of the elastic blade 1 is set to a substantially uniform value L11 in the first region w11, set to a substantially uniform value L13 in the third region w13, and set to a substantially uniform value L12 in the second region w12. In this way, in this embodiment, the elastic blade 1 has three regions of region w11, region w12, and region w13 in order from the central portion in the longitudinal direction toward the end portion, and has substantially uniform free lengths L11, L12, and L13 within each region. Here, the second region w12 is the region corresponding to the high-μ region. And the free lengths L11, L12, and L13 are set so as to satisfy the relationship L11 < L12 < L13. Note that the shape of the support sheet metal 2 is not limited to the shape shown in FIG. 19.

[0096] FIG. 20 is a schematic diagram showing the deformed state of the cleaning blade 3 in the high-μ region of this embodiment. By increasing the free length L12 of the elastic blade 1 in the high-μ region, the load applied to the elastic blade 1 can be released. Further, by increasing the free length L13 at the end portion in the longitudinal direction of the elastic blade 1, the load applied to the elastic blade 1 can be released more effectively. Therefore, the occurrence of blade curling is suppressed without the edge portion of the elastic blade 1 being largely drawn downstream in the moving direction of the surface of the image carrier such as the photosensitive drum 103 or the intermediate transfer belt 101.

[0097] 2. Explanation of cleaning failure On the other hand, in the region where the free length is set long, the contact pressure of the elastic blade 1 with the image carrier such as the photosensitive drum 103 or the intermediate transfer belt 101 decreases. As is clear from Figs. 17 and 19, since no toner is supplied to the region w13, no cleaning failure occurs. However, toner scattered from the end of the developing device 106 and the like are supplied to the region w12. Therefore, if the contact pressure near the boundary between the region w12 and the region w11 decreases too much, there is a possibility that cleaning failure will occur.

[0098] 21 is a graph showing the contact pressure distribution near the end of the elastic blade 1 in the longitudinal direction. When the free lengths L11, L12, and L13 are all 8 mm, pressure concentration occurs at the end of the elastic blade 1 and a corresponding pressure drop occurs near the region w12. When the free length L11 is 8 mm, and the free lengths L12 and L13 are 9 mm, there is an additional pressure drop due to the longer free length. When the free length L11 is 8 mm, and the free lengths L12 and L13 are 10 mm, the pressure drop becomes even more noticeable, and a significant pressure drop occurs near the boundary between the region w12 and the region w11. On the other hand, when the free length L11 is 8 mm, the free length L12 is 9 mm, and the free length L13 is 10 mm, the contact pressure near region w13 is lower compared to when the free length L11 is 8 mm, and the free length L12 and free length L13 are 9 mm, but there is almost no pressure drop near the boundary between region w12 and region w11.

[0099] Therefore, it is considered that a configuration in which the free length L11 is 8 mm, the free length L12 is 9 mm, and the free length L13 is 10 mm can more effectively relieve the load in the high μ region (region w12) to suppress the occurrence of blade curling, while preventing a pressure drop near the boundary between region w12 and region w11 to suppress the occurrence of poor cleaning. However, the present invention is not limited to these specific numerical values.

[0100] 3. Experimental Example 3-1. Experimental Example 4 A plurality of cleaning blades 3 having different values ​​of free lengths L11, L12, and L13 were prepared with the same configuration as this embodiment, and were mounted on the image forming apparatus 100 as the photoconductor cleaning blade 108 to carry out a continuous paper feed test to confirm the effect of this embodiment. A solid white image that is likely to cause blade curling was used as the image to be output in the continuous paper feed test. As shown in FIG. 17(a) and FIG. 19(a), the region w11 is the region corresponding to the development region, the region w12 is the high μ region that corresponds to the outside of the development region and the inside of the longitudinal width of the charging roller 104, and the region w13 is the region that corresponds to the outside of the longitudinal width of the charging roller 104. In the continuous paper feed test, the presence or absence of blade curling due to an increase in the number of sheets passed was confirmed. In addition, a predetermined test image was formed during the continuous paper feed test to confirm the presence or absence of cleaning failure (slip-through of toner).

[0101] The results of the continuous paper feed test are shown in FIG. 22. FIG. 22(a) is a table showing the occurrence of blade curling in the continuous paper feed test. FIG. 22(b) is a table showing the occurrence of cleaning failures in the continuous paper feed test. When the free lengths L11, L12, and L13 were all 8 mm, the blade curling occurred during the continuous paper feed test, but no cleaning failures occurred. Similarly, when the free length L11 was 8 mm, and the free length L12 and free length L13 were 9 mm, the blade curling occurred during the continuous paper feed test, but no cleaning failures occurred. Here, the number of sheets passed at the time when the blade curling occurred was greater when the free length L11 was 8 mm, and the free length L12 and free length L13 were 9 mm than when the free lengths L11, L12, and L13 were all 8 mm. On the other hand, when the free length L11 was 8 mm, the free length L12 was 9 mm, and the free length L13 was 10 mm, neither the blade curling nor the cleaning failures occurred. Furthermore, when the free length L11 was 8 mm, and the free length L12 and the free length L13 were 10 mm, no blade curling occurred, but poor cleaning occurred in the latter half of the continuous paper feed test.

[0102] Thus, in the photoreceptor cleaning blade 108, by setting the free lengths L11, L12, and L13 in the regions w11, w12, and w13 to satisfy the relationship L11 < L12 < L13, it is possible to suppress blade curling while suppressing the occurrence of cleaning failure.

[0103] 3-2. Experimental Example 5 A plurality of cleaning blades 3 having the same configuration as this example but different values of the free lengths L11, L12, and L13 were fabricated and mounted on the image forming apparatus 100 as the intermediate transfer member cleaning blade 102, and a continuous paper feeding test was conducted to confirm the effects of this example. As the image output in the continuous paper feeding test, a solid white image in which blade curling is likely to occur was used. As shown in FIGS. 17(b) and 19(a), the region w11 corresponds to the developing region, the region w12 corresponds to the high-μ region outside the developing region and inside the longitudinal width of the secondary transfer roller 111, and the region w13 corresponds to the region outside the longitudinal width of the secondary transfer roller 111. In the continuous paper feeding test, the presence or absence of blade curling due to an increase in the number of sheets fed was confirmed. Further, a predetermined test image was formed during the continuous paper feeding test to confirm the presence or absence of the occurrence of cleaning failure (toner leakage).

[0104] The results of this continuous sheet feeding test are shown in FIG. 23. FIG. 23(a) is a table showing the occurrence status of blade curling in the continuous sheet feeding test. Also, FIG. 23(b) is a table showing the occurrence status of cleaning failure in the continuous sheet feeding test. When all of the free lengths L11, L12, and L13 are 8 mm, blade curling occurred during the continuous sheet feeding test, but cleaning failure did not occur. Similarly, when the free length L11 is 8 mm and the free lengths L12 and L13 are 9 mm, blade curling occurred during the continuous sheet feeding test, but cleaning failure did not occur. Here, the number of sheets fed at the time when blade curling occurred was larger when the free length L11 is 8 mm and the free lengths L12 and L13 are 9 mm than when all of the free lengths L11, L12, and L13 are 8 mm. On the other hand, when the free length L11 is 8 mm, the free length L12 is 9 mm, and the free length L13 is 10 mm, neither blade curling nor cleaning failure occurred. Furthermore, when the free length L11 is 8 mm and the free lengths L12 and L13 are 10 mm, blade curling did not occur, but cleaning failure occurred in the latter half of the continuous sheet feeding test.

[0105] Thus, in the intermediate transfer body cleaning blade 102, by setting the free lengths L11, L12, and L13 in the regions w11, w12, and w13 so as to satisfy the relationship L11 < L12 < L13, it is possible to suppress the occurrence of cleaning failure while suppressing blade curling.

[0106] As described above, it is desirable that the first region w11 is a region corresponding to the developing region in the longitudinal direction, the second region w12 is a region corresponding to the outside of the developing region in the longitudinal direction and inside the longitudinal width of the charging roller 104 (or the secondary transfer roller 111), and the third region w13 is a region corresponding to the outside of the longitudinal width of the charging roller 104 (or the secondary transfer roller 111) in the longitudinal direction. However, similar to the description in the modification of Example 1, the free lengths L11, L12, and L13 in the regions w11, w12, and w13 are not limited to being substantially uniform. That is, similar to the description in the modification of Example 1, the average value of the free length L11 in the developing region is defined as the average free length L11a, the average value of the free length L12 inside the longitudinal width of the charging roller 104 (or the secondary transfer roller 111) outside the developing region is defined as the average free length L12a, and the average value of the free length L13 outside the longitudinal width of the charging roller 104 (or the secondary transfer roller 111) is defined as the average free length L13a. At this time, it may be set to satisfy the following formula: L11a < L12a < L13a.

[0107] Note that the cleaning blade 3 can be configured to satisfy the conditions described in this embodiment while satisfying the conditions described in Example 1.

[0108] [Others] As described above, the present invention has been described with reference to specific embodiments, but the present invention is not limited to the above-described embodiments.

[0109] For example, the configuration described in Example 2 may be applied to the configurations of Example 3 and Example 4. Further, the configuration described in Example 3 may be applied to the configuration of Example 4.

[0110] In the above-described embodiments, only the main parts related to the formation / transfer of the toner image have been described, but the present invention can be implemented in various applications such as printers, various printing machines, copiers, FAX machines, and multifunction machines by adding necessary devices, equipment, and housing structures.

Explanation of Reference Numerals

[0111] 1 Elastic blade 2 Supporting plate 100 Image forming device 101 Intermediate transfer belt 102 Intermediate transfer member cleaning blade 103 Photosensitive drum 104 Charging roller 105 Exposure equipment 106 Developing device 108 Photoconductor cleaning blade 111 Secondary transfer roller

Claims

1. an image carrier; a developer carrier that carries a developer and develops the latent image formed on the image carrier into a toner image; a cleaning member for removing developer from the surface of the image carrier, the cleaning member including: an elastic blade whose free end abuts against the surface of the image carrier along a width direction substantially perpendicular to the moving direction of the surface of the image carrier; and a regulating portion for regulating the free length of the elastic blade at a base end side opposite to the free end in a direction intersecting the width direction of the elastic blade; and at each of both end portions in the width direction, an end portion of a development area in which the developer carrier can carry a developer is located outside an end portion of an image forming area in which an image can be formed on the image carrier, and an end portion of a contact area in which the elastic blade and the image carrier come into contact is located outside the end portion of the development area, When the average value of the free lengths L1 [mm] of the elastic blade in the image forming region in the width direction is defined as an average free length L1a [mm], the average value of the free lengths L2 [mm] of the elastic blade outside the development region in the width direction is defined as an average free length L2a [mm], and the absolute value of the difference between the average free length L1a and the average free length L2a is defined as a free length difference ΔL [mm], the following formula is obtained: L2a ≧ 1.2 × L1a, L2≧L2a−ΔL×0.2, and L1≦L1a+ΔL×0.2 An image forming apparatus characterized by satisfying the above.

2. The following formula, L2≦L2a+ΔL×1.3 2. The image forming apparatus according to claim 1, wherein the following is satisfied:

3. When the free length of the elastic blade in the width direction inside the development area and outside the image forming area is L3 [mm], the following formula is satisfied: L1a<L3<L2a 2. The image forming apparatus according to claim 1, wherein the following is satisfied:

4. The image forming apparatus of claim 1, characterized in that the inner end of the region of the elastic blade in which the free length L2 in the width direction is approximately uniform is located at the same position as or further inward from the end of the development region, and at the same position as or further outward from the end of the image forming region, in the width direction.

5. The image forming apparatus according to claim 1, characterized in that the end of the region of the elastic blade in which the free length L1 in the width direction is approximately uniform is located in the width direction at the same position as or outside the end of the image forming region, and at the same position as or inside the end of the development region.

6. 2. The image forming apparatus according to claim 1, wherein the elastic blade has a treated portion impregnated with an isocyanate compound at an end portion in the width direction, and the inner end portion of the treated portion is located outside the end portion of the development area in the width direction.

7. The elastic blade has a first region in the width direction corresponding to the image forming region that has a substantially constant first free length, and a second region in the width direction that is outside the image forming region that has a second free length that is longer than the first free length and is substantially uniform; The processing section has an inner end portion positioned outside an outer end portion of the second region in the width direction.

2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

8. A contact member is provided which contacts the surface of the image carrier and to which a voltage is applied, at each of both end portions in the width direction, an end portion of a contact area where the contact member and the image carrier come into contact is located outside an end portion of the development area, a free length L12 [mm] of the elastic blade in the width direction outside the development area and inside the contact area is shorter than a free length L13 [mm] of the elastic blade in the width direction outside the contact area; 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

9. The image forming apparatus described in Claim 8, characterized in that the elastic blade has a region in which the free length L12 [mm] is approximately uniform outside the development region and inside the abutment region in the width direction of the elastic blade, and a region in which the free length L13 [mm] is approximately uniform outside the abutment region in the width direction of the elastic blade.

10. 9. The image forming apparatus according to claim 8, wherein the contact member is a charging member that charges the surface of the image carrier.

11. 9. The image forming apparatus according to claim 8, wherein the contact member is a transfer member that transfers an image formed with a developer from the image carrier to a recording material.

12. 12. The image forming apparatus according to claim 1, wherein the regulating portion is a support member that supports the elastic blade.

13. A support member for supporting the elastic blade, the regulating portion is a regulating member supported by the support member and regulating a surface of the elastic blade opposite to a surface of the elastic blade facing the image carrier; 12. The image forming apparatus according to claim 1, wherein the image forming apparatus is a recording medium.

14. 12. The image forming apparatus according to claim 1, wherein the image carrier is a photosensitive member.

15. 12. The image forming apparatus according to claim 1, wherein the image carrier is an intermediate transfer member that conveys a toner image that has been primarily transferred from another image carrier to a recording material in order to transfer the toner image onto the recording material.

Images