JPH0451159A - Image producing device - Google Patents

Abstract

PURPOSE:To prevent toner from adhering to a gear by disposing a rotor which is rotatably provided and a driving source which drives to rotate the rotor through a power transmitting means in a supporting structural body and providing an electret having the same polarity as the toner on the side of the gear functioning as the power transmitting means. CONSTITUTION:The electret E having the same polarity as the toner is provided on both sides of the gear 114 which drives to rotate a photosensitive drum 26. Even when the toner which flows out from the inside of a process unit 14 to the outside is going to adhere to the gear 114, it is repulsed and kept away from the gear because it has the same polarity as the gear, then it does not substantially adhere to a tooth space part. Thus, the toner is prevented from adhering to the space of the gear.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image generating apparatus such as an electrostatic copying machine or an electrostatic printing machine, and particularly to an image generating apparatus that prevents contamination by toner.

[Conventional technology]

In general, image generation is performed by electrostatically attaching charged fine particles (toner), which is a developer, to an electrostatic latent image formed on the surface of a photoreceptor to create a visible image, which is then transferred and fixed onto copy paper. The device has been well known and widely put into practical use.

An electrostatic copying machine as an example of this type of image generation device includes:
It is equipped with a unit frame that is removably mounted in a support structure ()\Using) and a process unit that includes an image output means such as a photosensitive drum (rotary drum) that is rotatably supported by the unit frame. (Refer to Utility Model Application Publication No. 63-86639). The electrostatic copying machine disclosed in the publication will be explained as a conventional technique with reference to FIGS. 3 and 4.

The illustrated electrostatic copying machine includes a box-shaped housing generally designated by the number 2. The housing 2 is composed of a so-called shell-shaped support structure consisting of a lower support frame 4 and an upper support frame 6 attached to the lower support frame 4. The lower left end of the upper support frame 6 is rotatably connected to the lower support frame 4 via a shaft 8 extending in the front-rear direction of the lower support frame 4, that is, in the direction perpendicular to the paper plane in FIG. There is.

On the upper surface of the housing 2, ie, on the upper surface of the upper support frame 6, a document mounting means 10 is mounted so as to be able to reciprocate in the left-right direction. The document placing means 10 includes a transparent plate 12 on which a document to be copied is placed, and a document cover (not shown) that can be opened and closed to cover the transparent plate 12 and the document placed thereon. ).

A process unit 14 located at the center of the housing 2 is removably attached to the upper support frame 6. The mounting structure is as follows.

That is, the upper support frame 6 has a pair of support rails 16 and 1 extending in a direction perpendicular to the plane of the paper at intervals in the left-right direction.
8 is fixed. On the other hand, the process unit 14 has a process unit frame 20 (unit frame 20), and supported parts 22 and 24 are provided at both left and right ends of the unit frame 20, extending in a direction perpendicular to the plane of the drawing. The supported parts 22 and 24 of this unit frame 20 are positioned on the support rails 16 and 18 of the upper support frame body 6, respectively,
By sliding the unit frame 20 in a direction perpendicular to the plane of the paper, the process unit 14 is detachably attached to the upper support frame 6.

At the center of the unit frame 20 is a photoreceptor drum (rotating drum) 2 on which an appropriate electrostatic photoreceptor is disposed on the circumferential surface.
6 is rotatably attached.

The unit frame 20 further includes a charging device (corona discharger for charging) 30, a developing device 32, and a cleaning device around the photosensitive drum 26, which is rotationally driven in the direction shown by an arrow 28. A device 34 is attached.

The developing device 32 includes a magnetic brush mechanism 3 that supplies toner, which is a developer, to the circumferential surface of the photoreceptor drum 260 in the developing container.
6 (including a developing roller), an agitation roller (not shown), and the like. The cleaning device 34 also includes an elastic blade 38 that comes into contact with the circumferential surface of the photoreceptor drum 26 and a toner collection chamber 40 . The cleaning device 34 is further provided with a ladle spiral roller (not shown) that conveys the residual toner scraped off by the elastic blade 38 into the collection chamber 40 .

The above-described photosensitive drum 26, charging device 30, and developing device 3
2, the cleaning device 34, and the like constitute an image output means. Regarding the above process unit 14,
This will be described further below.

The upper support frame 6 further includes the process unit 14.
Irradiation lamp 42 and reflection plate 44 located above
, and an optical system consisting of SELFOC Micro Lens (trade name) 46 and the like. Light from the irradiation lamp 42 passes through the transparent plate 12 and irradiates the document placed thereon, as shown by the dashed line. The reflected light from the original is transmitted through the SELFOC microlens 46 and the unit frame 20.
The light is projected onto the circumferential surface of the photoreceptor drum 260 in an exposure area 52 through an exposure opening 50 formed in the upper wall 48 .

At the center of the lower support 4, there is a transfer device (
A transfer corona discharger 56 and a stripping static eliminator 58 located downstream thereof are provided.

At the right end of the lower support 4, there is provided a copy paper supply means, generally indicated by the number 60, and at the left end, there is provided a copy paper tray 6.
2 is provided. A copy paper conveying system 64 for conveying the copy paper through the transfer area 54 is provided between the copy paper supply means 60 and the copy paper tray 62.

The copy paper supply means 60 includes a paper feed tray 66 and a pair of paper feed rollers 68 provided on the downstream side thereof.

Therefore, when copy paper is placed on the paper feed table 66 and inserted through the open lower 2 formed on the right wall 70 of the housing 2 to the paper feed roller pair 68, the paper feed roller rotates in the direction of the arrow. Due to the action of pair 68, copy paper is fed to copy paper transport system 64 through guide plate 74.

The copy paper transport system 64 includes a transport roller pair 76 and a lower guide plate 78.
, a guide member 80, a pair of heating and fixing rollers 82, and a pair of discharge rollers 84. These components define a copy paper transport path 86 that guides the copy paper fed from the copy paper supply means 60 to the copy paper tray 62. A heating means 90 is provided within the main heating roller 88 of the heating fixing roller pair 82 .

The unit frame 20 in the process unit 14 is
It has a front wall (not shown) and a rear wall 98 spaced apart in a direction perpendicular to the plane of the paper.

The above-described top wall 48, left side wall 102, right side wall 104, and bottom wall 100 are provided between the front wall and the rear wall 98.

A step is provided at the center of the upper wall 48 in the width direction, and the exposure opening 50, which is elongated in the front-rear direction, is formed in the center of the step. In addition, in the widthwise central part of the bottom wall 100,
A transfer opening 110 extending in the front-rear direction is formed. The lower part of the photosensitive drum 26 is exposed to the outside through the transfer opening 110.

A developing device 32 and a cleaning device 34 are provided along with the photosensitive drum 26 between the front wall and the rear wall 98 of the unit frame 20 .

The photosensitive drum 26 is rotatably supported between the front wall and the rear wall 98 via shaft portions provided at both ends (only one of them 111 is shown in the fourth I!I). Upper support frame 6 at the rear position of the rear wall 98 of the unit frame 20
is provided with a rear substrate 112 that extends vertically. A gear 114 is rotatably provided on the rear substrate 112 via a short shaft 116 . Shaft 1 of photoreceptor drum 26
11 is drivingly connected to the gear 114 via a clutch means 118 when the unit frame 20 is mounted on the upper support frame 6 and set in the operating position. This gear 114 is connected to a drive source (not shown) such as a motor via another gear serving as a power transmission means (not shown). When each gear is rotated by this drive source, the photosensitive drum 26 is rotated in the direction shown by an arrow 28.

In the electrostatic copying machine configured as described above, while the photosensitive drum 26 is rotationally driven in the direction shown by the arrow 28,
The charging device 30 substantially uniformly charges the photoreceptor of the photoreceptor drum 26 to a specific polarity, for example, a positive polarity. Next, in the exposure area 52, the image of the original on the transparent plate 12 is projected onto the photoreceptor through the exposure aperture 50 by the optical system, and a charged area corresponding to the image of the original, that is, an electrostatic latent image, is formed on the photoreceptor. is formed. This electrostatic latent image is developed into a toner image by supplying toner charged to a specific polarity, for example, a negative polarity, from the magnetic brush mechanism of the developing device 32.

The copy paper supplied from the copy paper supply means 60 and conveyed by the copy paper conveyance system 64 is brought into close contact with the peripheral surface of the photoreceptor drum 260 in the transfer area 54, and the toner on the photoreceptor drum 26 is transferred by the action of the transfer device 56. The image is transferred onto copy paper. Next, by the action of the stripping static eliminator 58,
The copy paper is peeled off from the photosensitive drum 26.

The peeled copy paper is conveyed through a pair of heating and fixing rollers 82, and the toner image on the copy paper is heated and fixed. The copy paper with the toner image fixed thereon is passed through an opening 94 in the left wall 92 of the housing 2 by a pair of ejection rollers 84 and delivered to the copy paper tray 6.
2.

- Force The photoreceptor drum 26 continues to rotate further, and toner remaining on the photoreceptor after transfer is removed by the action of the elastic blade 38 of the cleaning device 34. The removed toner is collected into the toner collection chamber 40 via a spiral roller.

The process unit 14 is detachably mounted within the housing 2 as described above. For this attachment and detachment, the process unit 14 is provided with a known handle (not shown), and is also provided with a suitable locking means between it and the housing 2. Therefore, if a trouble occurs in the image output means such as a photosensitive drum provided in the process unit 14, or if a predetermined life span is reached, the process unit 14 can be easily replaced with a new one.

[Problem to be solved by the invention]

In the conventional electrostatic copying machine described above, various types of rotatable bodies are provided within the housing 2, which is a support structure. That is, the rotating bodies in this example include the photosensitive drum 26 in the image output means of the process unit 14, the developing roller or stirring roller of the developing device 32, the spiral roller of the cleaning device 34, and the paper feed roller pair 68 in the copy paper supplying means 60. , a pair of conveyance rollers 76, a pair of heating and fixing rollers 82, a pair of discharge rollers 84, etc. in the copy paper supply system.

On the other hand, a predetermined number of drive sources such as motors for rotationally driving these rotating bodies are provided within the housing 2, and a gear serving as a power transmission means is provided between the drive source and the rotating bodies. (In I!I, only the gear 114 that rotates the photoreceptor drum 26 is shown).

In the electrostatic copying machine equipped with the gears as described above,
An image output means including a photosensitive drum 26, a developing device 32, etc. is provided in the process unit 14, which is removably installed in the housing. Inside the developing device 32,
Toner, which is charged fine particles, is stored as a developer. In other words, since toner is used as a developer, it scatters as the copying machine operates, causing damage to the process unit 14.
flows out from the opening of the gear, for example, located near the opening of the process unit 14,
It adheres to the tooth grooves of the gear 114 that drives the photoreceptor drum 26.

When toner adheres to the tooth grooves of the gear 114, smooth engagement between the gears is hindered, causing uneven driving and vibration.
This is transmitted to the photoreceptor drum 26, causing blurring, distortion, etc. in the image, and unevenness in image density. Therefore, a clear image is not guaranteed, and the life of not only the gear train but also the image output means including the photosensitive drum 26 is shortened.

In other gears, if toner adheres to the tooth grooves,
Similarly to the above, this causes misalignment of the gears, causing negative effects such as distortion of the copy paper, blurring of the transferred image due to blurring, and shortening of the life of parts related to the gear.

The present invention has been made based on the above-mentioned facts, and an object thereof is to provide an image generating apparatus that prevents toner from adhering to a gear that drives a rotating body.

[Means to solve the problem]

In order to achieve the above object, according to the present invention, a support structure includes a rotating body rotatably provided and a drive source for rotationally driving the rotating body via a power transmission means, An image generating apparatus using a gear as the power transmission means is provided, characterized in that an electret having the same polarity as the toner is provided on a side surface of the gear.

[Effect]

Image generation in which a support structure is provided with a rotating body rotatably provided and a drive source for rotationally driving the rotating body via a power transmission means, and a gear is used as the power transmission means. In the device, an electret having the same polarity as the toner is provided on the side of the gear.
Even if the toner that has flowed out from inside the process unit tries to adhere to the gear, since it has the same polarity as the gear, it is repelled and moved away from the gear, and does not substantially adhere to the tooth groove portion.

As is well known, an electric left is a charged body that generates an electric field semi-permanently outside and has electric polarization characteristics. The surface of the electret provided on the side of the gear (the surface exposed to the outside) is held to have the same polarity as the toner, so the toner is semi-permanently repelled and does not adhere.

〔Example〕

The present invention will be described in detail below with reference to FIGS. 1 and 2.

1 and 2 show an example in which the present invention is applied to the gear 114 that rotationally drives the photosensitive drum 26 in the copying machine shown in FIGS. 3 and 4, and the same parts are denoted by the same reference numerals. It is shown by .

As shown in FIGS. 1 and 2, on both sides of the gear 114, electrons (electrons) E (hatched portions in the figures) having the same polarity as the toner are provided.

As described above, electret is a charged body that semipermanently generates an electric field outside, has electric polarization characteristics, and is also known to be formed from various polymeric materials. Electron) E in this example is a film made of a copolymer of tetrafluoroethylene and hexafluoropropylene, which is suitable for having stable polarization characteristics, and is formed by a known electretization method.

As an electret formation means, for example, under predetermined conditions, a high DC voltage is applied at high temperature to both sides of the film, and then the film is cooled to room temperature, thereby obtaining an electret knot having different types of surface charges on both sides. Alternatively, a suitable method is to perform a corona discharge treatment on the surface of the film so that charges are trapped on the surface to generate electrets.

The film-like electret E that has been made into an electret in this way is attached to the gear 114 as described above using an adhesive.
electrets are provided on both sides of the gear 114. It is important that the electret E is attached to both sides of the gear 114 so that its exposed surface has the same polarity as the toner.

As shown in FIGS. 3 and 4, the process unit 14
When the toner is installed in a copying machine and a copying operation is performed, a portion of the toner flows out from the opening of the process unit 14, for example, the transfer opening 110 or the exposure opening 50. This toner is transferred to a gear 114 located near the process unit 14.
However, the electrets on both sides of the
is repelled by Therefore, the toner moves away from the gear 114 and does not adhere to the tooth grooves.

In the copying machine, as described above, in addition to the photosensitive drum 26, the rotating bodies using gears include the developing roller or stirring roller of the developing device 32, the spiral roller of the cleaning device 34, and the copy paper supply means 60. A paper feed roller pair 68 in the copy paper supply system, a conveyance roller pair 76 in the copy paper supply system, a heat fixing roller pair 82, and a discharge roller pair 8
There is a 4th prize.

The electret E can be provided, if necessary, on the side surface of the gear that drives these rotating bodies in the same manner as in the previous embodiment.

〔Effect of the invention〕

According to the invention described above based on the embodiments, an electret having the same polarity as the toner is provided on the side surface of the gear that drives the rotating body in the copying machine, thereby preventing toner from adhering to the tooth grooves of the gear. be done.

Therefore, drive unevenness in the gear that drives the rotating body,
Since blurring and the like are prevented and smooth meshing operation is maintained, clear images are guaranteed. Furthermore, there is no distortion of the copy paper, and smooth and accurate conveyance of the copy paper is guaranteed. Furthermore, the lifespan of equipment, devices, etc. associated with each gear can be maintained as specified.

Although the present invention has been described in detail based on the embodiments above, the present invention is not limited to the embodiments described above, and various modifications and modifications can be made within the scope of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing an embodiment in which the present invention is applied to the gear shown in FIG. 4. FIG. 2 is a perspective view showing a part of FIG. 1. FIG. 3 is a schematic cross-sectional view showing a conventional electrostatic copying machine. FIG. 4 is a schematic vertical cross-sectional view of FIG. 3, showing a part thereof. 2...Housing 6...Upper support frame 14...Process unit 20...Unit frame 26...Photoconductor drum 48...Soil Wall 112... Rear board 114... Gear E... Electret Figure 1 Figure 2

Claims (1)

[Claims] 1. A rotating body rotatably provided within the support structure;
In an image generating apparatus that includes a drive source for rotationally driving the rotary body via a power transmission means and uses a gear as the power transmission means, a side surface of the gear has the same polarity as the toner. An image generation device characterized by being provided with an electret. 2. The rotating body is a photosensitive drum supported within a process unit detachably mounted within a support structure;
The image generating apparatus according to claim 1, wherein the gear is a gear that drives the photosensitive drum.