Patent Application
20180120754
The present invention relates to an image forming apparatus using an electrophotographic system.
In an image forming apparatus, such as a printer using an electrophotographic image forming system (electrophotographic process), a cleaning unit is disposed to remove such deposited matter as toner from the surface of a movable body, such as a photosensitive member (photosensitive drum) and an intermediate transfer member, which are imaging bearing members to bear a developer image. For such a cleaning unit, a system to contact a cleaning member, such as a cleaning blade, to the movable body, is frequently used. The cleaning blade is normally a rubber blade, and a stable cleaning performance thereof is maintained by a very small amount of toner slipping through the gap between the movable body and the blade as a lubricant.
However as the quality of the material of the rubber blade improves, the cleaning performance improves, but the lubricating effect decreases, and in some cases self-induced vibration may be generated by the sliding friction between the photosensitive drum and the cleaning blade. In particular, in the case of the process cartridge type apparatus configuration, the self-induced vibration of the cleaning blade may become a vibration source, and propagate to the unit housing constituting the cartridge, resulting in the generation of an unpleasant noise.
As means to reduce the noise, a method of cancelling the sound by interfering with a sound in the opposite phase, using a speaker or the like, has been proposed (see Japanese Patent Application Publication No. H05-142887). A method, in which a cleaning blade includes a vibration detecting unit and vibration applying unit, and vibration is reduced by detecting the vibration of the cleaning blade using the vibration detecting unit and applying vibration in the opposite phase using the vibration applying unit, has also been proposed (see Japanese Patent Application Publication No. 2008-139750).
In the prior art, the vibration detecting unit, the vibration applying unit, the speaker and other additional composing elements are required, whereby control becomes complicated, and the cost of the process cartridge or the image forming apparatus increases.
It is an object of the present invention to provide a technique that can reduce noise using a simple configuration.
To achieve the above object, the cleaning apparatus of the present invention is a cleaning apparatus that is detachable from an apparatus main body of an image forming apparatus, comprising:
To achieve the above object, the cleaning apparatus of the present invention is a cleaning apparatus that is detachable from an apparatus main body of an image forming apparatus, comprising:
To achieve the above object, the process cartridge of the present invention is a process cartridge that is detachable from an apparatus main body of an image forming apparatus, comprising the cleaning apparatus.
According to the present invention, noise can be reduced using a simple configuration.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Hereinafter, a description will be given, with reference to the drawings, of embodiments (examples) of the present invention. However, the sizes, materials, shapes, their relative arrangements, or the like of constituents described in the embodiments may be appropriately changed according to the configurations, various conditions, or the like of apparatuses to which the invention is applied. Therefore, the sizes, materials, shapes, their relative arrangements, or the like of the constituents described in the embodiments do not intend to limit the scope of the invention to the following embodiments.
A general configuration of an electrophotographic image forming apparatus (imaging forming apparatus) according to an example of this invention will be described with reference to
The image forming apparatus 100 has a plurality of image forming portions, which are first, second, third and fourth image forming portions SY, SM, SC and SK, to form images having yellow (Y), magenta (M), cyan (C) and black (K) colors respectively. In this example, the configuration and operation of the first to fourth image forming portions are essentially the same, except that the color of the image to be formed is different. Therefore in the following, the image forming portion is described omitting Y, M, C and K unless a distinction is necessary.
The image forming apparatus 100 has four photosensitive drums 1 (1Y, 1M, 1C, 1K) as the image bearing members. The photosensitive drum 1 rotates in the arrow A direction figures. Around the photosensitive drum 1, a charging roller 2 (2Y, 2M, 2C, 2K) is disposed. The charging roller 2 here is a charging unit to evenly charge the surface of the photosensitive drum 1. Around the photosensitive drum 1, a developing apparatus (hereafter called “developing unit”) 4 (4Y, 4M, 4C, 4K) and a cleaning blade 106 (106Y, 106M, 106C, 106K), which is a cleaning unit (blade member), are disposed. Further, an intermediate transfer belt 5, which is an intermediate transfer member, to transfer a toner image on the photosensitive drum 1 to a recording material 12, is disposed so as to face the four photosensitive drums 1. In this example, the developing unit 4 uses a non-magnetic one-component developer, that is, toner T (TY, TM, TC, TK), as a developer. In this example, the developing unit 4 performs contact development by contacting a developing roller 22, which is a developer bearing member, with the photosensitive drum 1.
In this example, the photosensitive drum 1, the charging roller 2, the cleaning blade 106, and a removed developer storing portion (hereafter called “waste toner storing portion”) 17 (17Y, 17M, 17C, 17K) constitute a photosensitive member unit 13 (13Y, 13M, 13C, 13K). The untransferred toner (waste toner) remaining on the photosensitive drum 1 is removed from the photosensitive drum 1 by the cleaning blade 106, and is stored in the waste toner storing unit 17.
Further, in this example, the developing unit 4 and the photosensitive member unit 13 are integrated to a process cartridge 7 (7Y, 7M, 7C, 7K) for each color, so as to be detachable from the main body of the image forming apparatus 100. The process cartridge 7 is detachable from the image forming apparatus 100 via an inserting unit, such as an inserting guide and a positioning member (not illustrated) disposed in the image forming apparatus 100. In this example, the process cartridge 7 can be inserted into the main body of the image forming apparatus 100 in the arrow G direction in
The intermediate transfer belt 5 contacts all the photosensitive drums 1, and rotates in the arrow B direction in
When an image is formed, the surface of the photosensitive drum 1 is uniformly charged first by the charging roller 2. Then the surface of the charged photosensitive drum 1 is scanned and exposed by a laser light, which is emitted from the scanner unit 3 in accordance with the image information, and an electrostatic latent image corresponding to the image information is formed on the photosensitive drum 1. Then the electrostatic latent image formed on the photosensitive drum 1 is developed as a toner image by the developing unit 4. The toner image formed on the photosensitive drum 1 is transferred onto the intermediate transfer belt 5 (primary transfer) by the function of the primary transfer roller 8.
For example, when a full color image is formed, the above mentioned process is sequentially performed by the first to fourth image forming portions SY, SM, SC and SK, and a toner image of each color is sequentially superimposed on the intermediate transfer belt 5 as the primary transfer. Then synchronizing with the movement of the intermediate transfer belt 5, the recording material 12 is transported to the secondary transfer unit. Next by a function of the secondary transfer roller 9, which is in contact with the intermediate transfer belt 5 via the recording material 12, the four-color toner images on the intermediate transfer belt 5 are transferred onto the recording material 12 in batch as the secondary transfer. The recording material 12, on which the toner image was transferred, is transported to the fixing apparatus 10, which is a fixing unit. The toner image is fixed to the recording material 12 by the fixing apparatus 10 applying heat and pressure to the recording material 12, and the recording material 12 is discharged to the outside, and the image forming operation ends.
The primary untransferred toner, which remained on the photosensitive drum 1 after the primary transfer step, is removed by the cleaning blade 106. The secondary untransferred toner, which remained on the intermediate transfer belt 5 after the secondary transfer step, is removed by an intermediate cleaning apparatus 11. The removed untransferred toner is discharged to a waste toner box 14 of the image forming apparatus 100. The image forming apparatus 100 can also form a single color or a multi-color image using only a desired single or a plurality of (not all) the image forming portions.
A general configuration of the process cartridge 7, which is attached to the image forming apparatus 100 of this example, will be described with reference to
The developing unit 4 includes a developer storing chamber (hereafter called “toner storing chamber”) 18a, a developing chamber 18b in which the developing roller 22 is disposed, and an opening 18c which connects the toner storing chamber 18a and the developing chamber 18b. In the developing chamber 18b, a toner supply roller 20 which is a developer supply member which contacts the developing roller 22 and rotates in the arrow E direction, and a developing blade 21 which is a developer control member, to control the toner layer of the developing roller 22, are disposed. A stirring member 23, which stirs the stored toner T and transports the toner to the toner supply roller 20 via the opening 18c, is disposed in the toner storing chamber 18a of the developing frame 18. The stirring member 23 includes a rotation shaft 23a disposed in parallel with the rotation axis line direction of the developing roller 22, and a stirring sheet 23b, which is a flexible sheet member of which one end is installed in the rotation shaft 23a, stirs and transports the toner.
The photosensitive member unit 13 includes a cleaning frame 114, which is a frame to support various composing elements in the photosensitive member unit 13. The photosensitive drum 1 is installed in the cleaning frame 114 so as to be rotatable in the arrow A direction in
The cleaning blade 106 is integrally formed by an elastic member 106a, constituted by such an elastic body as rubber to remove the untransferred toner or residual toner (waste toner) remaining on the surface of the photosensitive drum 1 after the primary transfer, and a support member 106b, constituted by a metal plate to support the elastic member 106a. The waste toner removed from the surface of the photosensitive drum 1 by the cleaning blade 106 drops into the space formed by the cleaning blade 106 and the cleaning frame 114 in the gravity direction, and is stored in the waste toner storing portion 17.
A method of fixing the cleaning blade 106 to the cleaning frame 114 will be described with reference to
The support member 106b, constituted by an electro-galvanized zinc plated steel or the like has a bend portion and reinforcing portion so as to improve rigidity. A fixing hole 106c1 and a fixing hole 106c2 are formed on both ends of the support portion 106b1 respectively, at least in the axis line direction (hereafter called “longitudinal direction”) of the photosensitive drum 1.
In the cleaning frame 114, an engaging portion 114a1 and an engaging portion 114a2 are disposed respectively at positions facing the fixing holes 106c1 and 106c2 of the cleaning blade 106. Screws 107 are fixed to the engaging portions 114a1 and 114a2 of the cleaning frame 114 respectively via the fixing holes 106c1 and 106c2, whereby the cleaning blade 106 is supported and secured by bearing surfaces 114b1 and 114b2 (fixed portions). Here the cleaning blade 106 is fixed to the cleaning frame 114 by screws on both ends of the cleaning blade 106, but the present invention is not limited to this, and adhesive, welding, insert molding or the like may be used.
The disposition of the vibration absorbing members will be described with reference to
In the cleaning frame 114, on the other hand, a first support portion 114c is disposed at least in a region L (see
Now tan δ will be described. The tan δ is a physical property called a “loss factor (loss tangent)”, and is determined by the tangent of the stress and the loss angle δ of strain, that is, the ratio of the storage shear modulus and the loss shear modulus, and indicates how much energy the material absorbs when the material deforms. The tan δ can be measured by a dynamic viscoelasticity measuring apparatus. δ is a phase shift (phase difference) between the sine wave of a vibration strain applied to the measurement object and the sine wave of a stress in a measurement result, and indicates the change amount of δ per unit time. In other words, the slope of the sine wave indicates the strain rate. The strain rate, that is, the slope of the sine wave, is the maximum when the strain is 0, and is the minimum (0) when the strain is the maximum. Since the elasticity depends on the strain, and the viscosity depends on the strain rate, the phase difference δ becomes closer to 0° as the ratio of the storage shear modulus, which is an elastic component, is higher, and the phase difference becomes closer to 90° as the ratio of the loss elastic modulus, which is a viscous component, is higher. Therefore tan δ indicates an energy amount that is absorbed when the material deforms, and a greater attenuation effect can be obtained as the value of the loss factor tan δ is greater.
The vibration of the cleaning blade and the disposition of the vibration absorbing member will be described with reference to
Here the normal vector P of the second plane 106f of the cleaning blade 106 is disposed to have an angle θ from the normal vector N of the first plane 106e, and in this example the angle θ is 90°. Thereby the Y direction component of the vibration of the cleaning blade 106 can be attenuated by the second vibration absorbing member 102, and the Z direction component of the vibration of the cleaning blade 106 can be attenuated by the first vibration absorbing member 101 respectively, and as a result, the vibration of the cleaning blade 106 can be effectively reduced. In other words, by disposing a vibration absorbing member for two surfaces having different angles, not only the vibration in one direction but the vibration from various directions orthogonal to the drum axis line as well can be attenuated.
According to this embodiment, the support member 106b has an L-shaped cross-section, constituted by the support portion 106b1 in which the elastic member 106a is installed, and the reinforcing portion 106b2 which is connected with the support portion 106b1 via the bend portion 106b3. However, the support member is not limited to this, but may have any configuration if the support member has a first plane 106e and a second plane 106f, and the vibration absorbing member can be disposed in the first plane 106e and the second plane 106f of which angles are different from each other. A support member having a tubular shape or having a flat plate shape with a predetermined thickness may be used if constituted by a support portion in which the elastic member is installed, and a surface which is connected with the support portion via the bend portion.
Method of Installing Vibration Absorbing Member
A method of installing the vibration absorbing member will be described with reference to
The installation method is not limited to this, but the cleaning blade 106 may be installed in the cleaning frame 114 in which the vibration absorbing members are two-color molded. Alternatively, a vibration absorbing member may be adhered to either the cleaning frame 114 or the cleaning blade 106 first, then the cleaning blade 106 may be installed in the cleaning frame 114.
The seal configuration of the waste toner storing portion 14a will be described with reference to
Since the second vibration absorbing member 102, which is a vibration absorbing member, also functions as a seal member (sealing member) which seals the toner inside the waste toner storing portion 17, it is unnecessary to add a separate seal member, whereby a process cartridge can be provided at low cost.
In this example, the second vibration absorbing member 102 also functions as a seal member, but the first vibration absorbing member 101 may be configured as a seal member, or both the first and second vibration absorbing members 101 and 102 may be configured as seal members.
As described above, according to this example, a cleaning apparatus or a process cartridge having a configuration to reduce noise can be provided at low cost by effectively attenuating the vibration of the cleaning blade.
Now another example of this invention will be described. The basic configuration of the image forming apparatus and the process cartridge of this example is the same as Example 1. Therefore a composing element which is the same as or equivalent to Example 1 is denoted with the same reference sign, and detailed description thereof is omitted.
In Example 2, the second vibration absorbing member 102 is disposed between the second support portion 114d and the second plane 106f, not in the entire region along the photosensitive drum 1 in the axis line direction, but only in the region having the length less than ¼ of this region, including the center in the longitudinal direction along the axis line. In concrete terms, the cleaning blade 106 is fixed with the screws 107 and 107, so that the cleaning blade 106 is biased toward the cleaning frame 114, and is supported and secured by the bearing surfaces 114b1 and 114b2 disposed on both ends of the cleaning frame 114 in the axis line direction of the photosensitive drum 1. Therefore in the axis line direction, the vibration amplitude is highest at the middle point between the screws (fixed members) 107 and 107. Hence, if the second vibration absorbing member 102, of which length is ¼ of the length of the second support portion 114d, is disposed in the axis line direction (on a middle point) between the screws 107 and 107, such that the middle point, at which vibration is the greatest, is included in the axis line direction, then the vibration can be sufficiently suppressed. Here a material having high dynamic viscoelasticity is used for the second vibration absorbing member 102, and for example, a rubber having high vibration resistance, of which loss factor tan δ measured when a 100 Hz frequency of vibration is applied at the measurement temperature of 23° C.±2° C., is at least 0.6 and not more than 2.0, is used confirming to JIS K 6250.
For the sealing of the wasted toner storing portion, the seal member 115 is disposed in the entire region in the axis line direction. The seal member 115 prevents the leakage of the waste toner through the gap between the second support portion 114d of the cleaning frame 114 and the second plane 106f of the cleaning blade 106 in the entire region in the axis line direction. For the seal member 115, a material of which tan δ is small and repulsion is as low as possible, compared with the second vibration absorbing member 102, such as urethane foam, is used. In this configuration, the second vibration absorbing member 102 is disposed at the center portion in the longitudinal direction, where the vibration amplitude is highest, therefore vibration is sufficiently suppressed, and the seal member 115, of which tan δ is small, is disposed in the other region, thereby the coupling force between the cleaning blade 106 and the cleaning frame 114 is reduced, and the vibration transfer path can be minimized.
Further, in this example, as illustrated in
By the above configuration, both suppressing vibration and reduction of the vibration transfer paths can be implemented, and a cleaning apparatus which can attenuate the vibration of the cleaning blade and reduce noise more effectively can be provided.
The configurations of the examples and modifications described above may be combined. For example, the first vibration absorbing member of Example 1 or each modification may be added to the configuration of Example 2.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Applications No. 2016-213548, filed on Oct. 31, 2016, and No. 2017-165699, filed on Aug. 30, 2017, which are hereby incorporated by reference herein in their entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2016-213548 | Oct 2016 | JP | national |
| 2017-165699 | Aug 2017 | JP | national |
