JPH07302025A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a discomfort noise and also to prevent vibration by use of a vibration proof member by shifting a resonance frequency outside a discomfort frequency band by a weight member incorporated with a photoreceptive drum. CONSTITUTION:The photoreceptive drum 11 is provided with a built-in assembled body 40 which is constituted by integrally assembling the weight member 41 capable of shifting the resonance frequency of a vibration system including the photoreceptive drum 11 and a cleaning blade 15 outside the discomfort frequency band and the vibration proof member capable of absorbing the vibration. Even in the case the cleaning blade 15 as a cleaning member is slid in contact with the surface of the photoreceptive drum 11 so as to remove the sticking toner when the device is operated, the resonance frequency of the photoreceptive drum 11 constituting the vibration system and the resonance frequency of the cleaning blade 15 are drastically reduced by the weight member 41 incorporated with the photoreceptive drum 11, and the frequency is shifted outside the discomfort frequency band, so that the occurrence of the discomfort noise is prevented, and also, the vibration is prevented by the vibration proof member 45, then, a noise level is drastically lowered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus for removing toner adhering to a photosensitive drum with a cleaning member.

[0002]

2. Description of the Related Art FIGS. 9 and 10 show a conventional structure of an image forming apparatus. In these drawings, reference numeral 1 is an apparatus body case, 10 is a photosensitive drum unit, 20 is a developing unit, and 21 is an exposure unit. Further, 25 is a paper feed unit (paper feed tray 26, paper feed roller 27, etc.), 28 is a conveyance roller, and 30 is a fixing device (heating roller 31, pressure roller 3).
2).

The photoconductor drum unit 10 comprises a photoconductor drum 11, a charging device 12 and a cleaning device 14. Usually, the photosensitive drum 11 is formed of aluminum alloy into a cylindrical shape, and a photosensitive layer is formed on the surface thereof. The photoconductor drum 11 has a length equal to or larger than the width of the maximum size sheet, and is thin in order to reduce the cost.

In the above image forming apparatus, the charging device 1
The electrostatic latent image on the photoconductor drum 11 formed by the laser beam B charged by 2 and emitted from the exposure unit 21 is developed with the toner supplied from the developing unit 20,
After that, the toner image is transferred by the transfer device 13 onto the paper P sent from the paper feed section 25 through the carrying roller 28, and is fixed by the fixing device 30.

After the transfer, the toner remaining on the photosensitive drum 11 is separated and collected by the cleaning device 14. The cleaning device 14 is a cleaning member (rubber cleaning blade 15) that is in sliding contact with the photosensitive drum 11.
Further, it is generally configured to include an accommodating portion (accommodating portion 17A of the drum unit case 17) for accommodating the waste toner separated by the blade 15 and sent through the collecting roller 16.

[0006]

By the way, in the above-mentioned conventional image forming apparatus, the cleaning blade 1 is used.
Since 5 is slidably in contact with the surface of the photoconductor drum 11, the drum 11 may be thin and the resonance sound is likely to be generated.

When such a resonance sound is generated, the user feels uncomfortable.
There have been various attempts to improve the airtightness and sound insulation, but there is a problem that it tends to lead to an increase in the size and cost of the device.
Further, it has been pointed out that even if the noise level is reduced to a considerable extent, the user's discomfort cannot be eliminated. Generally, in an image forming apparatus, other operating noises are small, and thus the above-mentioned resonance noises tend to be particularly unpleasant.

In view of the above circumstances, an object of the present invention is to prevent the occurrence of resonance noise that gives an unpleasant feeling to an operator and to significantly reduce the noise level without increasing the size and cost of the apparatus. An object of the present invention is to provide an image forming apparatus capable of performing the same.

[0009]

SUMMARY OF THE INVENTION According to the present invention, increasing the airtightness and sound insulation of the main body of the apparatus to prevent noise generation tends to increase the size and cost of the apparatus, which is problematic. Focusing on the fact that there is a frequency band of the sound to be sensed, the vibration system including the photosensitive drum, which is the source of noise (including unpleasant sound), and the cleaning member causes the sound including the component in the unpleasant frequency band due to the weight effect. It is intended to achieve the above-mentioned object by preventing the occurrence of vibration and vibration.

That is, the image forming apparatus according to the present invention is
In an image forming apparatus in which a cleaning member is brought into sliding contact with the surface of a photosensitive drum to remove toner attached to the surface, the resonance frequency of a vibration system including the photosensitive drum and the cleaning member is shifted from an unpleasant frequency band. A possible weight member and a vibration damping member capable of absorbing vibration are incorporated in the photosensitive drum.

[0011]

According to the present invention having the above-described structure, even if the cleaning member slides on the photosensitive drum to remove the adhered toner during operation, the weight member incorporated in the photosensitive drum causes the components of the vibration system to be separated. Since the resonance frequency is outside the unpleasant frequency band, unpleasant noise is prevented from being generated, and vibration is also prevented by the vibration isolating member, which significantly reduces the noise level.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) As shown in FIGS. 1 and 2, the present image forming apparatus has the same basic configuration as that of the conventional example (FIGS. 9 and 10), and the weight member 41 and the vibration isolator are attached to the photosensitive drum 11. The member 45 is built in so that the unpleasant noise can be prevented from being generated and the noise level can be significantly reduced without increasing the size and cost of the device. The conventional example (FIGS. 9 and 1)
0) The same reference numerals are given to the same components as
The description will be simplified or omitted.

First, the weight member 41 is used for the photosensitive drum 11.
Due to its weight effect, the resonance frequency of the vibration system including the photosensitive drum 11 and the cleaning member (the rubber cleaning blade 15 in this embodiment) is outside the unpleasant frequency band (250 to 300 Hz). It is formed to be shiftable to. Further, the vibration isolator 45 is formed in the photoconductor drum 11 so as to be able to absorb vibration.

In this embodiment, the weight member 41 and the vibration isolating member 45 are integrally assembled. With such a configuration, the weight member 41 and the vibration isolator 45 have their respective functions (resonance frequency shift function, vibration isolator function) greatly improved by a synergistic action, and the handling is further facilitated.

Specifically, the weight member 41 is made of iron and steel and is formed in a cylindrical shape at a low cost and easily exerting a weight effect. The weight member 41 is formed so that its weight does not exceed 1.2 times the weight of the photosensitive drum 11. This is because an excessive load is not applied to the drive system of the photoconductor drum 11. In this embodiment, the weight of the weight member 41 is the maximum weight (1.2 times the weight of the photosensitive drum 11). In addition, the inner diameter of the weight member 41 is equal to the photosensitive drum 11
The outer diameter of the shaft 11s is slightly larger than that of the shaft 11s.

Further, the vibration-proof member 45 is formed in a cylindrical shape from a highly elastic rubber material so that it can be easily assembled to the weight member 41. The vibration-proof member 45 is the weight member 4
It is mounted on the outer peripheral surface of No. 1 without any gap. The anti-vibration member 45 is formed such that the diameter of the outer peripheral surface of the anti-vibration member 45 is slightly larger than the inner diameter of the photosensitive drum 11 when mounted on the weight member 41.

The assembly 40, in which the anti-vibration member 45 is assembled to the weight member 41, is press-fitted into the photosensitive drum 11 and fixed at the center of the drum 11 in the axial direction. The assembly 40 is fixed at the central position in the photoconductor drum 11 because the bushes (11b, 1b, 1b) are provided at both ends of the photoconductor drum 11.
Since the resonance can be suppressed by 1b), it is arranged farthest from the bushes (11b, 11b) at the central position where resonance is likely to occur.

Next, the operation of the first embodiment will be described. During operation, even if the cleaning blade 15 as a cleaning member slides on the surface of the photoconductor drum 11 to remove the adhered toner, the weight member 41 built in the photoconductor drum 11 causes the photoconductor forming the vibration system to be exposed. The resonance frequency of the body drum 11 (600 Hz in this embodiment) and the resonance frequency of the cleaning blade 15 (250 to 300 Hz in this embodiment) are both significantly reduced, and are outside the unpleasant frequency band (250 to 300 Hz) (that is, Since the vibration component within the unpleasant frequency band is completely eliminated), the generation of unpleasant sound is prevented and the vibration isolator 45
Vibration is also prevented and the noise level is significantly reduced.

According to the first embodiment, however, the weight member 41 capable of shifting the resonance frequency of the vibration system including the photosensitive drum 11 and the cleaning blade 15 from the uncomfortable frequency band and the vibration can be absorbed. Since the assembly 40, which is integrally assembled with the anti-vibration member 45, is built in the photoconductor drum 11, the resonance sound that gives the operator discomfort without increasing the size and cost of the apparatus. Can be prevented, and the noise level can be significantly reduced.

Further, since the weight member 41 and the vibration isolating member 45 are integrally assembled, the handling is further facilitated, and the functions of both members (41, 45) are further enhanced by the synergistic effect. It is possible to more effectively prevent the generation of unpleasant sound and significantly reduce the noise level.

Further, since the outer peripheral portion of the assembly 40 is formed of the rubber vibration isolating member 45, it can be easily press-fitted into the photosensitive drum 11, and even if the drum 11 rotates, it is displaced from the central position. There is nothing to do.

Further, since the assembly 40 has a structure in which the weight member 41 of the heavy object is arranged inside and the vibration damping member 45 of the light weight is arranged outside and both of them are formed in a cylindrical shape, the moment of inertia does not become large, and A rotational imbalance is not generated, smooth rotation is ensured without hindering the rotational drive of the photosensitive drum 11.

Further, although the weight member 41 and the vibration isolating member 45 are integrally assembled, they may be separately incorporated in the photosensitive drum 1. With this configuration, it is possible to save the trouble of assembling the both.

(Second Embodiment) The second embodiment is shown in FIGS.
Shown in. In the image forming apparatus according to the second embodiment, the weight member (41) and the vibration isolating member (45) are integrally formed of a rubber material, and the integrally formed rubber material (hereinafter referred to as a weight vibration isolating / combining member 40E). .) Is built in the photosensitive drum 11. The same components as those in the first embodiment (FIGS. 1 and 2) are designated by the same reference numerals, and the description thereof will be simplified or omitted.

The weight anti-vibration member 40E is formed so that its weight does not exceed 1.2 times the weight of the photoconductor drum 11 even at the maximum, as in the first embodiment. Further, the weight anti-vibration member 40E is press-fitted into the photoconductor drum 11 and fixed at the center position of the drum 11 in the axial direction.

In particular, in the second embodiment, in consideration of the fact that the weight anti-vibration member 40E is entirely made of a rubber material, the weight anti-vibration member 40E is provided with the cutout portion 51 to provide the photosensitive member. The drum 11 is configured to be smoothly and easily pressed into the drum 11.

In determining the shape of the notch portion 51, as shown in FIGS. 5 to 7, prototypes (40EP) of the weight anti-vibration / combined member having various notch shapes are manufactured and press-fitting experiments and the like are performed. I went there.

FIG. 5 shows a prototype 40EP having a cutout portion 54 formed by parallel cutout surfaces (55, 56). The prototype 40EP could be smoothly and easily pressed into the photoconductor drum 11, but the holding force in the photoconductor drum 11 was weakened, and the prototype 40EP moved.

FIG. 6A shows a prototype 40EP having a notch portion 57 formed of notch surfaces (58, 59) formed in a V shape. The prototype 40EP could be smoothly and easily press-fitted into the photoconductor drum 11 and could be surely kept held at a predetermined position in the photoconductor drum 11, as shown in FIG. As described above, when the photoconductor drum 11 is press-fitted, the inner diameter portion may be deformed abnormally, and the smooth insertion of the shaft 11s may not be performed.

Therefore, the present inventor has proposed the above-mentioned prototype 40EP.
Based on the results of various experiments and theoretical considerations, etc., check the shape of the notch (51) that can be press-fitted into the photoconductor drum 11 without abnormal deformation of the inner diameter and has good retention after press-fitting. It started.

A weight anti-vibration member 40E having such a cutout portion 51 is shown in FIGS. 7 (A), 7 (B) and 7 (C). The notch portion 51 of the member 40E for weight vibration damping also has a notch surface (52, 53) formed over the entire length L in the axial direction of the member 40E. Notch surface (52, 5
At least one center portion in the thickness direction of 3) is formed so as to project toward the other. In this embodiment, the notch surfaces (52, 53) are respectively formed in the thickness direction central portion (52
At t, 53t), the protrusion amount is maximum, and the cross-section is formed in a mountain shape so as to be in contact.

Therefore, when the weight anti-vibration member 40E is press-fitted into the photosensitive drum 11, the notched surfaces (52, 53) of the member 40E are pressed to elastically deform and compress the entire peripheral surface shape. be able to. Therefore, the press-fitting operation can be performed quickly and easily. At this time, the notch surface (52, 53) is formed in the thickness direction central portion (52t, 53).
Since it is elastically compressed and deformed from t), the outer diameter portion and the inner diameter portion are not abnormally deformed.

After the press-fitting, the center portion (52t, 53t) in the thickness direction of the notch surface (52, 53) of the weight / vibration damping member 40E.
t) is in pressure contact with the photosensitive drum 1 due to its elastic restoring force.
Since the inner surface of 1 is strongly pressed, it can be surely kept in the predetermined position.

In this second embodiment, however, the rubber weight anti-vibration member 40E is incorporated in the photosensitive drum 11, so that the apparatus can be made larger without increasing the size, as in the first embodiment. It is possible to prevent the generation of resonance noise that gives an operator discomfort, and to significantly reduce the noise level. In addition, handling becomes dramatically convenient, and further cost reduction can be achieved.

Further, since the notch 51 is formed in the weight anti-vibration member 40E, the outer diameter portion and the inner diameter portion can be press-fitted into the photoconductor drum 11 without abnormal deformation, and the outer diameter portion can be pressed. The inner surface of the photoconductor drum 11 can be firmly adhered to the photoconductor drum 11, and the photoconductor drum 11 can be reliably held at a predetermined position (center position). Further, the shaft 11s can be smoothly inserted.

Further, the notch surface (52, 5) of the notch portion 51.
Since 3) has a mountain-shaped cross section, when press-fitting the inside of the photoconductor drum 11, the central portions (52t, 53t), which are the largest protruding portions, in the thickness direction can be surely brought into pressure contact with each other to be elastically compressed and deformed. Therefore, abnormal deformation of the outer diameter portion and the inner diameter portion of the weight anti-vibration member 40E in the photoconductor drum 11 can be prevented more reliably, and the holding force in the drum 11 is further increased. Moreover, the smooth insertion of the shaft 11s can be performed more reliably.

In the second embodiment described above, the notch surface (52, 52) forming the notch portion 51 of the weight vibration isolating member 40E.
Although any of the central portions (52t, 53t) in the thickness direction of (53) is formed so as to project toward the other party, FIG. 7 (B)
As shown in FIG. 5, only one of the notch surfaces (52, 53) may be formed so that only one central portion (here, 52t) in the thickness direction thereof projects toward the other party. In addition, the notch surface (52, 5
The protruding shape of 3) is not limited to the mountain shape, and for example, as shown in FIG.
As shown in (C), it may be formed into a trapezoidal cross section.

In the first and second embodiments, one assembly 40 (or weight anti-vibration member 40E) is incorporated in the central position of the photosensitive drum 11, but the assembly is concerned. 40 (or weight anti-vibration member 40E) is divided into a predetermined number (for example, three divisions as shown in FIG. 8),
The divided parts (40A, 40B, 40C) may be arranged in a dispersed manner in the axial direction. With this configuration, the resonance of each part of the photosensitive drum 11 can be suppressed more effectively, and the generation of unpleasant sound can be prevented more effectively.

[0039]

According to the present invention, the weight member capable of shifting the resonance frequency of the vibration system including the photosensitive drum and the cleaning member from the uncomfortable frequency band and the vibration damping member capable of absorbing the vibration are exposed. Since the structure is built in the body drum, it is possible to prevent the occurrence of resonance noise that gives an unpleasant feeling to the operator and to significantly reduce the noise level without increasing the size and cost of the device.

[Brief description of drawings]

FIG. 1 is a sectional view for explaining a first embodiment of the present invention.

FIG. 2 is a sectional view for explaining a positional relationship between a cleaning drum and a photosensitive drum having a weight member and a vibration isolation member built therein.

FIG. 3 is a sectional view for explaining a second embodiment of the present invention.

FIG. 4 is a sectional view for explaining a positional relationship between a photosensitive drum having a built-in weight anti-vibration member and a cleaning blade.

FIG. 5 is also a diagram for explaining an example of a prototype manufactured to determine the shape of the cutout portion of the weight anti-vibration member.

FIG. 6 is a diagram for explaining another example of a prototype manufactured to determine the shape of the cutout portion of the weight anti-vibration member as well.

FIG. 7 is also a diagram for explaining the shape of the cutout portion of the weight anti-vibration member.

FIG. 8 is a view showing an assembly (or a weight anti-vibration member) which is divided and built in the photosensitive drum.

FIG. 9 is a diagram illustrating a conventional configuration of an image forming apparatus.

FIG. 10 is a diagram for explaining the positional relationship between the photosensitive drum and the cleaning blade, similarly.

[Explanation of symbols]

 11 Photoreceptor Drum 15 Cleaning Blade (Cleaning Member) 40 Assembly 40E Weight / Anti-Vibration Member 41 Weight Member 45 Anti-Vibration Member 51 Notch

Claims (1)

[Claims] 1. An image forming apparatus in which a cleaning member is brought into sliding contact with the surface of a photosensitive drum to remove toner adhering to the surface, and a resonance frequency of a vibration system including the photosensitive drum and the cleaning member is set. An image forming apparatus characterized in that a weight member capable of shifting to an uncomfortable frequency band and a vibration damping member capable of absorbing vibration are built in the photosensitive drum.