JPH0262564A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent electrostatic charging efficiency from decreasing by generating electrostatic charges uniformly on the surface of a photosensitive drum through the corona charging of a charge wire, attracting a suspensions such as toner on an absorption filter according to an air flow generated by an attraction quantity, and removing contaminants. CONSTITUTION:When the image forming device begins to operate, the photosensitive drum 7 is charged uniformly by an electrostatic charger 8. This electrostatic charger 8 is provided with a shield case 40 which is open downward and a charge wire 41 whose both ends are extended is provided to its internal wall part. There is a duct 43 on the top surface part of the wire 41 through a slit 42, the upper part of the duct 43 is connected to a suction device 45, and a suction filter 46 is further provided. Corona discharge is generated with a voltage impressed to the wire 41 to supply charges uniformly to the surface of the drum 7 and when the suction device 45 starts sucking operation, the air flow is generated as shown by an arrow (b). Consequently, suspension such as toner are sent to the suction device 45 and absorbed by the filter 46.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an image forming apparatus using electrophotographic technology.

(Prior Art) Conventionally, in image forming apparatuses using electrophotographic technology, in order to charge a photoreceptor before exposure, Japanese Patent Publication No. 56-138747 is used.
A belt 788 as described in the publication is provided. However, when the charging device has the shape of a shield case with an opening, it is difficult for the air inside the shield case to move. Because contaminants such as toner and silicone vapor accumulate inside the shield case, the corona t that is stretched inside the shield case inside the charging
There was a drawback that these contaminants adhered to the Ii electrode wire, resulting in a decrease in charging efficiency.

(Problems to be Solved by the Invention) As mentioned above, in conventional image forming apparatuses, contaminants such as scattered toner accumulated in the main unit adhere to the corona discharge electrode wire, reducing charging efficiency. There was a drawback to that.

Accordingly, the present invention provides an image forming apparatus that removes contaminants from inside the band M device and prevents a decrease in charging efficiency.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above-mentioned problems, the present invention provides an image forming means having an image bearing member that forms an electrostatic latent image, and a and a charging means for uniformly charging by corona discharge, and a sulin that is opened in the wall of the charging means to allow ventilation]-
and a duct which is disposed on the outer surface of the charging means and whose end is in close contact with the slit so as to completely cover the slit, and a suction means provided at the other end of the duct for sucking air from the slit. An image forming apparatus is provided.

(Function) When the image forming apparatus is powered on and starts operating, the suction means connected to the duct provided in the charging means operates, and the contaminants accumulated in the shield of the charging means are sucked through the slit. Remove.

This prevents contaminants from adhering to the corona discharge electrode wire of the charging means, making it possible to prevent a decrease in charging efficiency.

<Example) Hereinafter, an explanation will be given with reference to one embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of a copying machine as an image forming apparatus according to an embodiment of the present invention. A document table 2 is provided on the upper surface of the copying machine main body (hereinafter referred to as "main body top"), and an upper wheel paper cassette section 3 and a non-feed paper cassette section 4 are provided on the right side of the main body. A top paper cassette 31 and a non-feed paper cassette 41 are installed. The cassette cover of the overprint paper cassette 31 serves as a manual feed tray 51 for manually feeding MP1 for copying as appropriate.
This is called a manual paper feed section 5. The copy paper taken out at each paper feed section is sent to a pair of registration rollers 19. Main body 1
A paper discharge tray 6 is attached to the left side surface of the paper.

Next, the internal structure of the main body 1 will be explained. A photosensitive drum 7 is disposed approximately at the center of the main body. Around the photosensitive drum 7, a charging device 8. Optical system 9.
Phenomena device 10. Transfer charger 11. Charger for peeling 12.
A cleaning device 13, a static elimination lamp 14, and the like are sequentially arranged. Below the photosensitive drum 8, copy paper P1. P2
A copy paper conveyance path 17 is formed that guides the copy paper and P3 from the paper stop switch 18 to the paper discharge tray 7.

A vapor stop switch 18 is installed around the copy paper transport path 17 from the upstream side. Registration roller pair 19, transfer charger 11. Charger for peeling 12. Fixing device 20. A paper ejection device 21 and a paper ejection tray 6 are sequentially arranged. The fixing device 20 includes a heat roller 201 and a pressure roller 202.

The heat roller 20s and the pressure roller 202 are provided above and below the copy paper conveyance path 17. heat roller 20
1 and the pressure roller 202 are rotationally driven to sandwich the copy paper and transport the toner image on the copy paper downstream while heating and fixing the toner image. The paper ejection device F21 is provided with two rollers and a paper ejection switch SW. The copy paper is pinched and discharged by two rollers, and at this time, the paper discharge switch SW is turned on. The ejection of copy paper is detected by turning on the ejection switch SW.

Further, each of the above-mentioned paper feed sections is provided as a pre-process of the copy paper conveyance path 17. The upper paper cassette section 3 is configured with the following device as means for supplying the copy paper P2 stored in the upper paper cassette 31 to the copy paper transport path 17. From the one closest to the overprint paper cassette 31, the pickup roller 15, the paper feed roller 312, and the separation roller 31.
3 etc. appear. The unfed paper cassette section 4 is a unfed paper cassette 4.
The copy paper P3 stored in the copy paper conveyance path 17
The means for supplying the water is comprised of the following equipment.

Pickup row 5 from the side closest to unfeeding paper cassette 41
16. A paper feed roller 314, a separation roller 315, etc. appear. The manual paper feed unit 5 feeds the copy sheets P1 stacked on the manual paper feed tray 51 to the paper feed roller 312 of the upper wheel paper cassette unit 3.
This is a device that supplies the liquid to the separation roller 313, and is composed of a feed roller 311 and the like.

The optical system 9 described above includes an exposure lamp 28. whose back is surrounded by a reflector 25. Mirrors M1 to M6 and lenses 28
It has a configuration with.

Inside the main body, an upper frame and a lower frame (not shown) are pivotally supported at one end via a support shaft (not shown), and the loose ends of both frames are set at a predetermined angle, for example, about 30 degrees.
It is constructed so that it can be released at a time.

Inside the upper frame, there is a charger 8 for charging around the photoreceptor drum 7. Optical system 9. Exposure lamp 26°! Equipment W1
110. It has a configuration in which various devices such as a purification device 13 and a static elimination lamp 14 are provided. Furthermore, the upper frame has a document table 2. Main paper feed cassette section 3 and manual paper feed section 5
is attached to constitute the upper unit 1A.

The lower frame has a sketch paper cassette section 4. Transfer charging 1
11. Charger for peeling 12. Fixing device 20° Paper discharge device 21
Various mechanisms such as a paper ejection tray and a paper ejection tray are provided by appropriate means, and constitute a lower unit 1B.

After the front cover of main body 2 is rotated and removed, it is configured to be openable and closable approximately along the copy paper transport path 17 via a housing opening/closing device (not shown).

With such a housing that can be opened and closed along the copy paper transport path 17, the various rollers interposed therein can be easily replaced.

The operation of the apparatus configured as described above will be explained below.

The photoreceptor drum 7 is moved by a drive mechanism (not shown) as indicated by the arrow a in the drawing.
direction in synchronization with the optical system 9.

During operation, the temperature of the surface of the photosensitive drum 7 that carries a toner image is controlled within a predetermined range. I will explain this Seisan Somori later. When the operation starts, the photosensitive drum 7 is uniformly charged by the charging device 8. Next, the exposure lamp 26 uniformly irradiates the document with light, and a projected image of the document by the scattered light is formed on the photoreceptor drum 7 by the optical system 9, thereby forming an electrostatic latent image.

The developing device 10 develops the electrostatic latent image on the photoreceptor drum 7 with toner. The toner image formed on the photosensitive drum 7 as described above is sent onto the transfer charger 11.

On the other hand, the copy paper P1, P2 or P3 (hereinafter referred to as copy paper P) supplied from each paper feed section is fed by a pair of registration rollers 1.
By the rotation of 9, the image is conveyed onto the transfer charger 11. The start of rotation of one pair of registration rollers is sequence controlled as the vapor stop switch 18 is turned on. This sequence control is to synchronize the toner image on the photoreceptor drum 7 and the copy paper P so that they overlap.

The toner image on the photoreceptor drum 7 is transferred onto the copy paper P supplied onto the transfer charger 11 by the transfer charger 11 . The copy paper P to which the toner image has been transferred is separated by a peeling band l!
It is peeled off from the photoreceptor drum 7 in the device 12 and transferred to the fixing device 20.
be led to. A toner image is melted and fixed on the copy paper P by a fixing device 20, and the copy paper P is guided to a paper discharge device r121. Then, the copy paper P is discharged to the paper discharge tray 6 by the paper discharge device 21 . At this time, the paper ejection switch SW is turned on once and the copy paper P
Detects paper ejection.

On the other hand, when the toner image on the photoreceptor drum 7 is transferred to the copy paper P, the residual toner remaining on the photoreceptor drum 7 is
The cleaning device 11'13 is cleaned. Furthermore, the afterimage of the charge on the photosensitive drum 7 is erased by the static elimination lamp 14 in preparation for the next copying operation.

The above series of operations is performed by a microcomputer that controls motor lamps, heaters, etc. for customers in a certain sequence in response to signals from the operation switch, the detection switch provided at each location, and the corresponding signal output means. This is achieved through control.

Next, the above-mentioned charging device 8 will be explained in detail with reference to FIGS. 1 and 3.

FIG. 3 is a perspective view of the charger 8 for charging.

A charging device 8 is connected to a shield case 4 that is open downward.
0 is set. A charge wire 41 with both ends stretched is provided on the inner wall of the shield 40. For example, the upper surface of the shield 4o in the figure is 20 CI vertically and 5 CI horizontally.
A 1I11 slit 42 is formed. shield 4
A duct 43 made of an insulating material is provided above the shield 40 so as to completely cover the slit 42 and be in close contact with the upper surface of the shield 40. A small hole 44 is formed in a part of the duct 43. At the outer periphery of the small hole 44, there is a suction 4
145 is provided. The suction device 45 is composed of, for example, a fan. An adsorption filter 46 is provided behind the suction device 45 . The first view of this charging charger 8 viewed in the direction of the arrow along line D-D' is
It is a diagram.

As shown in FIG. 1, the charge wire 41 includes a power source 5.
0 is set. The charge wire 41 generates a corona discharge due to the applied voltage from the ff1i50, and charges are uniformly supplied onto the surface of the photoreceptor drum 7.

When the suction device 45 in FIG. 1 starts a suction operation, an airflow is generated as indicated by the arrow in the figure. Following this airflow, fine floating matter such as toner is sent to the suction device 45. The floating matter sent to the suction device 45 is adsorbed by an adsorption filter 46.

A device having the above-mentioned configuration can be said to be efficient because it can reduce the number of maintenance operations and can be changed at a cost that is less than the maintenance cost. The present invention
The present invention is not limited to the embodiments described above. The size of the slit and the surface of the shield on which the slit is formed do not matter, and the same effect can be achieved even if the slit is formed on another surface! ? can be done. Further, the number of slits is not limited to one, and multiple slits may be provided. In this case, the suction effect of floating objects within the shield can be further improved. Furthermore, the present invention can be applied not only to a multifunction printer but also to an image forming apparatus such as a laser beam printer using an electrophotographic method to obtain similar effects.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to remove contaminants inside the charged image and prevent a decrease in charging efficiency.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention. FIG. 1 is a sectional view of a charging device, FIG. 2 is a schematic sectional view of a copying machine, and FIG. 3 is a sectional view of a charging device. FIG. 3 is a perspective view of a charger. 8... Charger for charging, 40... Shield, 41...
・Charge wire, 42...slib 1-143...
Duct, 45...Suction device

Claims (1)

[Scope of Claims] An image forming means having an image bearing member for forming an electrostatic latent image; a charging means for uniformly charging the image bearing member by corona discharge; A slit is provided in the wall surface to allow ventilation; a duct is provided on the outer surface of the charging means and has one end in close contact with the charging means so as to completely cover the slit; and a duct is provided at the other end of the duct to allow air to flow through the slit An image forming apparatus characterized by comprising a suction means for suctioning.