JPH0916052A - Image forming device - Google Patents

Abstract

PURPOSE: To reduce noise produced in an image forming device, especially, the noise heard because electrification noise by a contact electrifying member is leaked from an exposure aperture part to the outside of a copying device when an original platen is located at a reversal position toy simple, constitution. CONSTITUTION: This image forming device is provided with the original platen 3 moving back and forth in order to scan a placed original, the exposure aperture part 9 through which image exposure light from the scanned original passes and which is positioned at the upper part of a device main body, and an image forming means forming the image exposure light, which passes through the aperture part 9 and is guided into the device main body, into an image on a sheet material by an electrophotographic system; and also provided with a screen plate 8 (shutter means) closing the aperture part 9 in a state where the original platen 3 is located at the reversal position in moving back and forth.

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 reading an image by a moving platen system and forming an image read by an electrophotographic system on a sheet material.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus which is an electrophotographic copying apparatus forms an image by the following process.

That is, the surface of a photoreceptor, which is an image bearing member, is charged by a charging device, and thereafter, imagewise exposure is performed to form an electrostatic latent image on the photoreceptor, and this latent image is supplied from a developing device. The image is developed by developing with toner, and this image is transferred from the photoconductor to the recording paper by the transfer means. After that, the residual toner on the surface of the photoconductor is removed by the cleaning means, and the photoconductor is again subjected to the charging process by the charging device.

The charging device used in the above image forming process will be described in detail. The charging device is a means for uniformly charging the surface of the photoconductor, and a contact charging type device is used as an example. The contact charging device applies a voltage (for example, 1 to 3) to the surface of the photoconductor as the member to be charged.
Roller charging is performed by bringing the surface of the photoconductor to a predetermined potential by contacting the photoconductor with a conductive member as a voltage contact charging member to which an AC voltage having a peak-to-peak voltage of about kV and a DC voltage) is applied. Type, blade charging type and the like.

The contact charging member is provided with a plurality of types of resistive layers having a higher electric resistance value than the substrate on a conductive substrate (generally the central axis of metal), and the outermost layer of the resistive layer is brought into contact with the surface of the photoreceptor. ing. The contact charging member uses a material in which conductive powder is dispersed in an elastic body such as rubber or resin so as not to damage the photoreceptor. Also, in the case where the contact charging member is pressed against the photosensitive member by supporting the metal shaft with a spring or the like in order to stabilize the contact between the contact charging member and the photosensitive member and to uniformly charge the surface of the photosensitive member. is there.

Recently, a contact charging member, an image bearing member, etc., which are integrated into a process cartridge and are attachable to and detachable from the main body have been used.

[0007]

However, when an AC voltage is applied to the above-mentioned contact charging member, the contact charging member and the photosensitive member are in contact with each other, so that a charging sound is generated in accordance with the frequency, which is offensive to the ears. there were.

Particularly when a contact charging system for applying an AC voltage is used in a movable copyboard type copy machine, when the moving copyboard is near the reverse position, the edge of the copyboard is near the exposure opening of the copy. Therefore, even if the magnitude of the generated charging sound does not change, the charging sound leaking from the gap of the document table becomes large. In addition, the volume of the charging sound may be different depending on the position of the moving document table, and as a result, it may be easier to perceive than the constant charging sound and may give an unpleasant feeling.

The present invention has been made to solve the above-mentioned problems of the prior art. The object of the present invention is to prevent the noise generated by the image forming apparatus, especially the charging sound of the contact charging member, from the original position of the document table. It is to reduce the sound that leaks from the exposure opening to the outside of the copying apparatus at a certain time by a simple structure.

[0010]

In order to achieve the above object, in the invention according to the present application, an image forming apparatus for scanning a document by a document platen moving system, which scans a placed document. The original table that reciprocates in the direction, the exposure opening located above the main body of the device that passes the image exposure of the scanned original, and the image exposure that is guided through the exposure opening into the main body of the device by electrophotography. In an image forming apparatus including an image forming unit that forms an image on a sheet material, in a state in which the document table is in a reciprocal reversal position,
Shutter means for closing the exposure opening is provided.

It is also preferable that a sound insulating member which abuts each other in the state where the document table is in the reciprocating reversal position is provided so as to face both ends of the document table and the exposure opening in the reciprocating direction.

Further, it is also preferable that the sound insulation member is a foamed elastic body, and each of them has an abutting slope.

[0013]

According to the present invention constructed as described above, since the shutter means closes the exposure opening when the document table is in the reverse position, noise generated by the image forming means is prevented from leaking from the exposure opening. To prevent.

Further, the sound insulation members provided at both ends of the original table and the exposure opening in the reciprocating direction of the exposure opening abut against each other in a state where the original table is in the inverted position so that the original table and the upper surface of the apparatus are brought into contact with each other. By blocking the gap of (1), noise generated by the image forming unit is prevented from leaking to the outside of the image forming apparatus.

Since the sound insulation member is a foamed elastic body and each of which has a contact slant surface, when the document table is in the reverse position, they contact each other to shield the gap between the document table and the upper surface of the apparatus, and While the table is moving, the contact area of the noise passing through the gap between the document table and the upper surface of the apparatus is enlarged, and the noise generated by the image forming unit is attenuated.

[0016]

【Example】

(First Embodiment) FIG. 1 is an explanatory view of a first embodiment to which the present invention is applied, and is a sectional explanatory view of an image forming apparatus. The present embodiment is a copying machine of a type in which a document table 3 provided with a transparent glass is reciprocally moved to sequentially form an image of a document placed on the document table 3 on a photoconductor 1 rotating through an optical lens 7. Is.

The photosensitive member 1 is formed by laminating a photosensitive layer 1a on a grounded cylindrical conductive substrate 1b and rotates in the direction of arrow A. The charging roller 2 is always in contact with the photoconductor 1 by a pressing unit (not shown), and the charging roller 2 is driven to rotate as the photoconductor 1 rotates. The charging roller 2 has a structure in which an elastic resistance layer is disposed on a metal cored bar,
A predetermined AC bias and DC bias (for example, AC bias is a peak-to-peak voltage of 2000 v,
A DC bias of -650 V is applied to charge the photoconductor 1. Thereafter, the light emitted from the light source 5 such as a fluorescent lamp or a halogen lamp passes through the exposure opening 9 of the document by the reflection plate 6 to illuminate the document image, and the reflected light is formed on the photoconductor 1 through the optical lens 7. By forming an image, a latent image corresponding to the original image is formed on the photoconductor 1.

However, when an AC bias is applied to the charging roller 2, charging noise is generated because the charging roller 2 is in contact with the photoconductor 1. Since the charging roller 2 itself is inside the main body of the copying apparatus, the charging sound leaked to the outside is slightly reduced, but the generated charging sound is constant, but the volume of the sound heard varies depending on the position of the moving document table 3. The sound is best heard when the edge of the platen 3 comes close to the charging roller 2.

That is, sound leakage is maximized at the reversing position of the reciprocating platen such as the copy start position and the end position shown in FIG. 1, and the center of the platen 3 is charged by the charging roller 2 during the copying operation. The sound leakage is the smallest when it comes near. This is because the document table 3 is also a sound insulation member for charging sound, and when the document table 3 reaches the reversal position, the sound leaking from the exposure opening 9 cannot be sufficiently shielded and the gap 3a is formed. This is because the sound is heard louder as it travels upward through.

Therefore, according to the present invention, when the original table 3 as shown in FIG. 1 as the first embodiment is at the position at the start of copying (start position) and at the not-shown copying end position (back position). At both reversal positions, the exposure opening 9 is closed by the blindfold plate 8 as shutter means, and when the copyboard starts and the document table 3 moves, the blindfold plate 8 also moves in the direction of arrow F and is required as shown in FIG. The opening 9 is secured. With this configuration, even when the document table 3 is in both the start and back positions, the blindfold plate 8
The sound insulation effect by prevents the charging noise from being heard loudly.

In this embodiment, the movement of the blindfold plate 8 is as shown in FIG.
As shown in FIG. 3, the blindfold plate 8 is connected to the solenoid 10, and a signal is transmitted to the solenoid according to the position of the document table 3 to push and pull the blindfold plate 8 to open the document table exposure opening 9
It is designed to block and open. A mechanism for moving the blindfold plate 8 may be configured in cooperation with the moving mechanism of the document table 3.

The surface of the blind plate 8 on the optical lens 7 side is white or a surface such as a metal thin plate having a high light reflectance. This is because the developer is not consumed until immediately before the copying process, and it is necessary to irradiate the photoconductor 1 with light from the light source 5 as much as possible. Conventionally, a blank sheet or the like is pasted on the back surface of the leading edge of the document table 3.

In principle, the material of the blind plate 8 is preferably as high as the weight density of iron or the like from the viewpoint of sound insulation effect, but in this embodiment, the thickness is only several mm to several tens mm, Even if it is made of plastic resin or the like, there is no great difference in the sound insulation effect.

As the timing at which the blind plate 8 opens and closes the original plate exposure opening 9, two types of A type and B type are illustrated as shown in the timing chart of FIG. A
As for the type, the opening 9 is opened only during the copying operation, and the opening 9 is closed during movement of the document table 3 before and after the copying operation or when stopped, and the opening 9 is opened to the minimum necessary. The sound that leaks can be minimized.

The type B is intended to make the level of the charging sound that can be heard irrespective of the position of the document table 3 constant, so that the front end or the rear end of the document table 3 approaches the reversing position, that is, the charging roller 2. In response to this, the blind plate 8 closes the opening 9, and the blind plate 8 opens the opening 9 as the document table 3 is reversed and the end of the document table 3 becomes farther from the upper part of the charging roller 2 again. Either may be used.

In this embodiment as described above, the blind plate 8 is not only used as a sound insulating plate, but also an object such as a clip placed on the original table falls to the exposure opening to damage the light source lamp 5, or There is also an effect of preventing the lens 7 from being damaged.

(Second Embodiment) FIG. 4 shows a diagram of a second embodiment. FIG. 4 is an enlarged view of the manuscript table 3 and the vicinity of the exposure opening 9. The manuscript table 3 shows the front end portion 3F and the rear end portion 3B, and the middle portion is omitted.

In this embodiment, a sound insulating member is provided on the rear surface of the front and rear ends of the original table 3 and outside the exposure opening. When the leading edge of the document table 3 reaches the reversal position near the exposure opening,
The sound insulating member 12F at the front end of the document table 3 and the sound insulating member 11F on the main body 4 side contact with each other to close the gap and reduce the leakage of the charging sound. Similarly, when the rear end of the document table 3 reaches the reversal position near the exposure opening, the sound absorbing member 12B and the main body 4 at the rear end of the document table 3 are placed.
The sound absorbing member 11B on the side contacts and closes the gap, and the same effect is obtained.

The sound-insulating members 11 and 12 are preferably sound-absorbing members made of an open-cell foam elastic material such as polyurethane foam. The contact surfaces of these are fixed to the document table 3 and the main body 4 with a double-sided tape or an adhesive. In addition, the sound insulation member 1
The reference numerals 1 and 12 do not come into contact with the main body 4 and the original table 3 which are opposed to each other, other than the fixed surfaces of the original table 3 and the main body 4. This is to prevent the original table 3 made of transparent glass or plastic resin from being soiled or damaged, and the sound insulating members 11 and 12 which are always in contact with each other.
It is also to prevent damage and deterioration of the. As shown in FIG. 4, the sound insulating members 11 and 12 have an inclined surface with respect to the document table 3, and the inclined surfaces are in contact with each other at the inverted position of the document table 3. Since the contact surfaces of the sound insulating members are inclined with respect to the document table, the document table 3 and the main body 4 are not moved when the document table is moving and not in the reverse position.
Since the contact area of the sound passing through between the sound insulation members 11 and 12 becomes large, the effect of absorbing the sound can be increased.

As described above, in the present embodiment, since it is not necessary to provide a new electric circuit or a mechanical mechanism for the present invention only by disposing the member between the document table and the main body, the present invention can be applied at a low cost. It is possible and does not enlarge the device body.

[0031]

According to the present invention having the above-mentioned structure and operation, noise generated by the image forming means is prevented from leaking from the exposure opening, and at the same time, the volume of sound is changed due to the difference in the position of the document table. Therefore, it is possible to prevent the user of the image forming apparatus and the people nearby from feeling uncomfortable.

With the configuration in which the shutter means closes the exposure opening while the document table is in the reverse position, it is possible to completely block the leakage of the sound from the exposure opening to the outside of the apparatus, and to remove dust or foreign matter. Are prevented from entering the device.

Further, the sound insulating members provided at both ends of the original table and the exposure opening in the reciprocating direction of the exposure opening are brought into contact with each other in a state in which the original table is in the inverted position with a simple structure. A gap between the image forming apparatus and the upper surface of the apparatus is shielded to prevent sound generated by the image forming unit from directly leaking to the outside of the image forming apparatus.

Since the sound insulation member is a foamed elastic body and each of which has a contact slant surface, when the document table is in the inverted position, they contact each other to shield the gap between the document table and the upper surface of the apparatus, and the document sheet. While the table is moving, the contact area with the noise passing through the gap between the document table and the upper surface of the apparatus is enlarged, and the noise generated by the image forming means is attenuated.

[Brief description of the drawings]

FIG. 1 is an explanatory cross-sectional view of a copying apparatus according to a first embodiment of the present invention.

FIG. 2 is a sectional explanatory view during the copying operation according to the first embodiment of the present invention.

FIG. 3 is a timing chart showing a blindfold plate moving sequence according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram around an exposure opening portion according to a second embodiment of the present invention.

[Explanation of symbols]

 1 Photoreceptor 1a Photosensitive Layer 1b Base Layer 2 Charging Roller 3 Document Plate 3F Document Plate Front End 3B Document Plate Rear End 4 Body (Frame) 5 Light Source Lamp 6 Reflector 7 Lens 8 Blind Plate (Shutter Means) 9 Exposure Aperture 10 Solenoid 11F Main body side sound insulation member (front end side) 11B Main body side sound insulation member (rear end side) 12 Manuscript table side sound insulation member 12F Manuscript table side sound insulation member (front end side) 12B Manuscript table side sound insulation member (rear end side) 13 Development bias Supplying device 15 Charging bias supplying device P Recording paper A Photosensitive member rotating direction F Blind plate moving direction G Original table moving direction

Claims (3)

[Claims] 1. An image forming apparatus for scanning a document by a document table moving method, wherein a document table reciprocating to scan a document placed on the document table and image exposure of the scanned document are passed. Image formation including an exposure opening located at the upper part of the apparatus main body, and image forming means for forming an image exposure image guided through the exposure opening into the apparatus main body as an image on a sheet material by an electrophotographic method. The image forming apparatus according to claim 1, further comprising shutter means for closing the exposure opening in a state where the document table is in a reciprocating reversal position. 2. An image forming apparatus for scanning a document by a document table moving method, wherein a document table which reciprocates to scan a placed document and image exposure of the scanned document are passed. Image formation including an exposure opening located at the upper part of the apparatus main body, and image forming means for forming an image exposure image guided through the exposure opening into the apparatus main body as an image on a sheet material by an electrophotographic method. In the apparatus, a sound insulating member that abuts each other in a state where the document table is in the reciprocating reversal position is provided so as to face both ends of the document table and the exposure opening in the reciprocating direction. Image forming apparatus. 3. The image forming apparatus according to claim 1, wherein the sound insulation member is a foamed elastic body, and each has a contact slope.