JPS5853545Y2 - electrophotographic equipment - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electrophotographic device that forms an electrostatic image on a chargeable member using a screen having a large number of fine apertures and comprising at least a photoconductive member and a conductive member. It is.

The screen used in the present invention uses a photoconductive member, a conductive member, and sometimes an insulating member, etc., and has a large number of fine openings, and is constructed of several layers of the above-mentioned members.

By applying an electric charge to the screen and irradiating it with an optical image of the original, a primary electrostatic latent image is formed according to the image of the original, and an ion flow is generated according to the pattern of the primary electrostatic latent image on the screen. The passage is controlled to form a secondary electrostatic latent image on the chargeable member.

The electrophotographic technique described above is known from Japanese Patent Publication No. 48-5063, etc., and is generally referred to as an electrophotographic method using ion flow control.

The secondary electrostatic latent image formed on the chargeable member as described above is utilized by being image-fixed through a conventional developing device or fixing device.

In conventional screens, in order to increase the rate of formation of secondary electrostatic latent images, the above-mentioned screens are sometimes constructed in the form of a drum.

In addition, when the screen is configured in a drum shape, when forming an electrostatic latent image on the screen, a band or the like of a corona discharger or the like is attached to the inside of the drum-shaped screen through a predetermined latent image forming process.
It becomes necessary to arrange a static eliminating means.

However, it is mechanically difficult to arrange an object such as a corona discharger to be kept stationary inside the rotating drum-shaped screen.

An object of the present invention is to facilitate the installation of a corona discharger inside a rotating drum-shaped screen, and at the same time to rotatably hold the drum-shaped screen with a simple structure.

In this invention, a photosensitive screen with many fine openings is stretched over the opening of a drum-shaped frame, and fixed at the central axis position of the drum-shaped frame in the cylindrical direction. A shaft is provided, a drum-shaped frame body is rotatably held on the fixed shaft, and a holding means for the corona discharger is further provided so as to be moved in a fixed manner on the fixed shaft.

The present invention will be described below with reference to embodiments and explanatory drawings thereof.

1 to 5 are explanatory diagrams showing a method and structure for supporting a corona discharger in a drum-shaped frame according to the present invention, and FIG. 6 is an explanatory diagram showing an embodiment of an electrophotographic copying apparatus to which the present invention is applied. ,
7 and 8 are diagrams illustrating the structure of a photosensitive screen used in the copying apparatus shown in FIG. 6, and the process of forming an electrostatic latent image.

FIG. 1 shows a drum-shaped frame on which a photosensitive screen is stretched in a cylindrical shape.

In the figure, the drum-shaped frame 1 has ring-shaped cylindrical portions 2□, 2 at both ends.
2 are connected via a connecting band 3, and the part that becomes the connecting band becomes a non-image area.

Therefore, a drum-shaped frame 1 having a size that includes a plurality of non-image portions can have a plurality of connecting bodies 3.

That is, the screen portion stretched over the opening 4 of the frame 1 is used for image formation.

As an example of a method for tensioning the screen on the frame 1, the screen is tensioned in advance, depending on the flexibility of the screen itself, and in this state, the cylindrical portions 20, 2 of the frame 1 are stretched. Attach with adhesive, belt, etc.

Further, 5 in the figure indicates a screen stretched over the opening 4, and 6. ．． 6□ is a frame flange having a mechanism for attaching the frame 1 to the fixed shaft described below and rotatably holding the frame 1 to the fixed shaft.

The frame flanges 6□, 62 are fixed to the frame 1 to the cylindrical portion 2 by screws, welding, or the like.

In the present invention, the method for attaching the screen 5 to the drum-shaped frame 1 and the method for attaching the frame flanges 6 to the cylindrical portions 20 and 22 are discussed.
The fixing method of □ and 6□ is not limited in any way.

FIG. 2 is a partially sectional view showing a mechanism of an embodiment in which a corona discharger is installed inside a drum-shaped frame on which a screen constructed as described above is stretched.

That is, the drum-shaped frame 1 is rotatably supported by a tubular fixed shaft 8 by bearings 7□ provided inside frame flanges 62 fixed at both ends (only the right side is shown in the figure).

In this way, the screen 5 stretched over the frame 1 rotates about the fixed shaft 8, which is the rotating shaft support shaft of the drum-shaped frame 1, which is fixedly installed.

Note that one end of the frame 1 is provided with a mechanism that rotates in synchronization with other operating mechanisms within the apparatus (for example, in the case of a copying machine, an optical system or a transport mechanism for a chargeable member that forms a secondary electrostatic latent image). , has a gear 9 that meshes with the gear of the drive source.

The gear 9 may be integrated with the frame 1 in advance, or the gear 9 may be constructed by fixing means such as screws 10 or adhesive means such as welding as shown in the figure.

Next, the method of installing the corona discharger provided inside the frame 1 will be explained.A rail 13 is fixed to bolts 11 provided at appropriate intervals on the fixed shaft 8 with nuts 14 as shown in the figure.

The rail plate 13 has an opening 15 at one end through which the bolt 11 passes, and a guide rail 12 for mounting the corona discharger at the other end.

Then, a corona discharger 17 having a rail 16 is installed on the guide rail 12 of the rail plate 13.
6 and the guide rail 12 by sliding them in a fitting manner.

Note that the opening 15 is connected to the screen 5 and the corona discharger 17.
It is effective to make a slotted hole in order to adjust the distance between the

A connecting wire 18 connecting the corona wire 17° of the corona discharger 17 and a power source (not shown) is connected to an opening 19 in the fixed shaft 8.
is provided and guided into the shaft 8 to reach the power source.

Alternatively, the corona discharger can be easily attached to and detached from the frame 1 by providing a plug on the fixed shaft 8 or the corona shearer 17 side and separating the connection line from the power source with the plug.

In the figure, the bearing 20 of the fixed shaft 8 is a member fixed to a part 22 of the device by a screw 21, and the bearing of the fixed shaft 8 is also fixed to the member 20 by a screw 23 so as not to rotate. has been done.

Further, a screw 24 provided on the guide rail 12 determines the position of the corona discharger 17.

Further, 25 is a motor for driving the frame 1, and the gear 27 provided on the rotating shaft 26 and the gear 9 mesh with each other to rotate the frame 1.

FIG. 3 is a sectional view taken along the line A--A in FIG. 2, and the numbers of the same parts are assigned correspondingly.

In the embodiment shown in FIG. 4, the rotating mechanism of the drum-shaped frame 1 is the same as the device shown in FIG. 2, but the installation mechanism of the corona discharger is different.

In the figure, the corona discharger 28 is connected by a guide member 29 inserted into the tubular fixed shaft 8 and a support plate 31 fixed with screws 30.

Due to the above mechanism, the frame flange 6, the bearing 7□, and the fixed shaft 8 on the insertion side are cut out only when the support plate 31 is passing through.

The fifth frame shows a cross section taken along the line B-B in FIG. 4.

Note that the other configurations and functions are the same as those of the embodiment shown in FIG.
Explanation will be omitted.

Also, the same components are given the same numbers as in FIG. 2.

As described above, the present invention makes it possible to easily install a corona discharger inside a rotating drum-shaped screen and to rotate the screen with a simple configuration. It can also be applied to the installation of lamps, etc.

Next, an electrophotographic apparatus will be described as an example of an electrophotographic copying apparatus having the above mechanism.

FIG. 6 is a schematic illustration of a copying apparatus having a mechanism according to the present invention.

Before entering into the explanation of the above-mentioned apparatus, first, an example of the structure of the screen suitable for use in the apparatus and the electrostatic latent image forming process will be explained in the seventh section.
This will be explained using the diagram and FIG.

FIG. 7 is an enlarged cross-sectional view of the screen. In the figure, the screen 32 is arranged around a conductive member 33, such as a mesh made of stainless steel wire, which has fine openings so as not to block the openings.
A photoconductive member and an insulating member are thickly laminated and coated on one side, and numeral 34 indicates a photoconductive layer and numeral 35 indicates an insulating layer.

Further, the photoconductive member of the screen 32 is not thickly coated, while the conductive member 33 is somewhat exposed on both sides as shown in the figure.

Next, the process of forming an electrostatic latent image by the screen 32 shown in FIG. 7 will be explained with reference to FIGS. 8a to 8d.

The outline of this process includes a pre-charging step a, a discharging step b which is carried out simultaneously or sequentially with image exposure, and a full-surface exposure step C which is carried out as necessary, and will be explained in more detail below.

FIG. 8a shows a pre-charging process, in which the photoconductive layer 34
As a substance constituting S, the main carrier is a hole.
An example using a semiconductor made of e or its alloy will be shown.

For this reason, in the pre-charging, the insulating layer 35 is uniformly charged with negative polarity using a charging means such as a corona discharger.

Note that the side of the screen having the photoconductive layer is referred to as the B side, and the side on which the conductive member is exposed is referred to as the A side.

Due to the above-mentioned charging, holes are injected into the photoconductive layer 34 through the conductive member 33, and a layer of holes is formed at the interface between the photoconductive layer 34 and the insulating layer 35.

FIG. 8 shows that a positive corona discharge or a positive bias voltage is superimposed on the pre-charged screen 32 using light rays, radiation, etc. that react according to the characteristics of the photoconductive member, simultaneously or sequentially with image exposure. The results are shown in which a discharge was performed using a discharge means such as an AC corona discharger so that the surface potential of the insulating layer 35 became approximately positive.

Through the above steps, an electrostatic latent image is formed on the surface of the screen 32 according to the brightness of the original image.

Note that arrows in the figure indicate reflected light from bright areas of the original.

FIG. 8C shows the result of uniformly exposing the entire surface of the screen 32 which has undergone image exposure and the discharge described above.

Due to this entire surface exposure, the potential of the dark portion of the screen 32 changes to a potential proportional to the amount of charge on the surface of the insulating layer 35.

FIG. 8d shows a screen 320 created as above, in which the ion flow is modulated by the primary electrostatic latent image, and a secondary electrostatic latent image is formed on a recording material having a chargeable layer with the original image as a positive image. Indicates the state in which

In the figure, numeral 36 indicates a recording material such as an electrostatic recording paper consisting of an insulating layer 39 provided on a conductive support 38 which also functions as a counter electrode for the corona wire 37, a resin layer and a metal support.

The recording material 36 is placed against the primary latent image holding surface of the screen.
The insulating layer 39 is placed opposite the screen 32 side with an appropriate distance of 1 to 10 mm, while the corona wire 37 for forming the secondary electrostatic latent image is placed on the opposite side of the recording material 36 through the screen 32. , and when obtaining a positive image, a voltage 40 having a polarity opposite to that of the charge in the dark area of the screen 32 is applied.

A voltage 41 for accelerating electric field is also applied in the same direction.

Note that even if the primary electrostatic latent image on the screen 37 is caused by corona discharge to form a secondary latent image, the surface is made of an insulating material, so the charges generated will not attenuate at all, so the same primary electrostatic latent image Retention copying is possible in which a secondary electrostatic latent image is formed hundreds of times.

In a screen having the above structure, a similar electrostatic latent image forming process is performed.

Further, in the exposure step, the direction of exposure to the screen is not limited to the above-mentioned direction.

The screen 43 used in the copying device 42 using the electrophotographic method is made of a 200-mesh conductive member made by knitting stainless wire with a diameter of 40μ, and CdS dispersed in a resin solution so as not to block the openings of the member. Apply the particles with a spray.

At this time, a CdS layer is attached to the conductive member by spraying so that the maximum thickness is approximately 50 μm and a portion of the conductive member is exposed.

On the CdS photoconductive layer thus obtained, an insulating material is further applied by spray coating to a thickness of about 20 μm.

Each layer of the screen may be applied before or after the screen is applied to the drum-shaped frame.

The screen 43 produced as described above is placed in a drum-like form in a copying machine by the supporting mechanism of the drum-like frame 44 according to the present invention.

When forming a primary electrostatic latent image in accordance with the original image on the screen 43, first the pre-charging corona discharger 45
Charged to 500V.

Thereafter, on a screen 43 that rotates in the direction of the arrow, a tachibana (not shown) placed on a glass plate of a mobile stall 46 is illuminated by a lamp 47 and equipped with reflecting mirrors 48, 49 and an aperture mechanism. The original image is exposed through the lens system 50.

Incidentally, simultaneously with the exposure of the original image, a corona discharge is applied by the corona discharger 51 using an AC current.

Since the discharge device 51 performs discharge and image exposure at the same time, the back surface of the shield plate of the discharge device 51 is optically open.

Next, the screen 43 is uniformly exposed to light by the lamp 52, with -70V for bright areas of the original image and +200V for dark areas.
A primary electrostatic latent image consisting of a surface potential of V is formed.

(2) The screen 43 having the secondary electrostatic latent image is rotated to the position where the secondary electrostatic latent image is formed.

Note that by this time, the paper feed cassette 53 has been installed at the formation position.
The electrostatic recording paper 54 stored in the paper is transferred one by one through the register roller 56 by the rotation of the feed roller 55.
It is conveyed by a conveyor belt 58 containing a suction means 57.

The register roller 56 is operated by a known control means such as a signal element so that the position of the primary electrostatic latent image on the screen 43 and the recording paper 54 match at the position where the secondary electrostatic latent image is formed. be.

As described above, the screen 43 corresponding to the formation position of the secondary electrostatic latent image receives the corona ion flow from the drum-shaped frame 44 and the corona discharger 59 arranged inside by the mechanism of the present invention. A secondary electrostatic latent image is formed on the recording paper 54 by applying an electric current to an electrostatic recording paper 541 placed at a distance of 3 mm from the primary electrostatic latent image.

In the corona discharger 59, a negative polarity corona discharge is performed from the corona wire 591 while applying a voltage of -3 KV to the conductive member of the screen 43. If necessary, the conveyor belt 58 is coated with conductive paint. The belt 58 is coated with
It is also effective to apply a bias voltage to the

The recording paper 541 on which the secondary electrostatic latent image has been formed is then conveyed to the developing device 61 by the conveying roller 60.
The image was visualized using conventional electrophotography, and the image was visualized using a roller 62°6.
3 is conveyed to a fixing device 65 by a belt 64 stretched around the belt 64 .

Here, the electrostatic recording paper passes through the developing device 61, and the developed image is fixed to the recording paper by a heating roller 65□ containing a heat source, and is ejected to the outside of the apparatus by a guide plate 66 to complete a copy image. do.

Note that when performing retention copying, the screen 43 is simply rotated to a predetermined position and two copies are placed on the recording paper without moving the document table 46 or forming a series of primary electrostatic latent images.
Since it is only necessary to form an electrostatic latent image, the copying speed becomes much faster than the conventional method when a large number of copies are to be made.

In addition, in the figure, 67 on the outer periphery of the screen 43 is the screen 4
This is a lamp for pre-exposure for 3, and the lamp 67
A primary electrostatic latent image is formed by applying a constant light coverage to the sensitive screen.

Further, 68 is a cleaning means for removing conductive dust adhering to the screen 43 which is particularly harmful to the formation of the primary latent image, and is composed of a brush, a suction mechanism, etc.

Next, 69 inside the screen 43 is a light shielding plate made of black felt or the like to prevent the light rays applied to the screen 43 during each exposure from having an adverse effect on other parts of the screen 43.

72 is a fixed shaft that supports the frame 44; 75 is the fixed shaft 72;
This is a connecting member between the discharger 59 and the discharger 59.

A corona discharger 70 provided near the conveyance path of the recording paper
This is a corona discharger for removing static electricity to remove frictional charge caused when recording paper is fed out.

Further, the corona discharger 71 is a corona discharger for grounding or applying bias during development of the recording paper.

In addition, when toner is used in the developing device, it is preferable to include a mechanism to prevent toner from scattering.

The above invention can also be applied to electrophotographic devices that use plain paper; in this case, a secondary electrostatic latent image is formed on an insulator, developed with toner, etc., and then transferred to plain paper. The developed image is transferred.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a drum-shaped frame, FIG. 2 is a partial sectional view of the device showing a method of supporting the corona discharger in the drum-shaped frame according to the present invention, and FIG. 3 is a view of the device shown in FIG. A-A line sectional view,
FIG. 4 is a cross-sectional view of an apparatus showing another embodiment of the above-mentioned supporting method, and FIG. 5 is a cross-sectional view taken along the line B--B of the apparatus shown in FIG. FIG. 6 is an explanatory diagram of the configuration of a copying machine which is an embodiment of the present invention, and FIGS. 7 and 8 a to 8 d are an example of the configuration of a screen that can be used in the present invention and the process of forming a latent image. It is an explanatory diagram. In the figure, 1... drum-shaped frame body, 2...
...Cylindrical part, 5...Screen, 8...
・Fixed shaft, 12...Guide rail, 13...
...Rail plate, 16...Rail, 17...
... Corona discharger, 20 ... Bearing is a member, 3
2...screen, 36...recording material,
43...Screen, 44...Drum-shaped frame, 59...Corona discharger, 72...
・・Fixed axis.

Claims (1)

[Scope of Claim for Utility Model Registration] In an electrophotographic device that controls the passage of ion flow using an electrostatic latent image formed on a photosensitive screen and forms an electrostatic latent image on a chargeable member, the photosensitive screen is stretched. a cylindrical drum-shaped frame, a fixed shaft fixed to the apparatus main body, and a drum-shaped frame support means for rotatably supporting the drum-shaped frame on the fixed shaft; A driving force transmission means for rotationally driving the drum-shaped frame, and a modulation corona discharger mounted on the fixed shaft for non-contact verification on the inside of the rotating drum-shaped frame. An electrophotographic apparatus comprising: means for supporting a corona discharger.