JPH043085A - Transferring device - Google Patents

Abstract

PURPOSE:To decrease the friction resistance between a transfer material guiding member and a transfer material so as to smooth the transportation of the transfer material and to simplify the construction by providing a transporting mechanism for delivering the transfer material diagonally upward and the transfer material guiding member having the guiding surface on the rear surface side for guiding the transfer material to a transfer position. CONSTITUTION:The paper guiding member 30 for guiding the paper 18 is disposed between the transporting rollers 21a, 21b for delivering the paper 18 diagonally upward and a photosensitive drum 11 to guide the paper 18 along the guiding surface 32 toward the transfer position of the photosensitive drum 11. Namely, this device is constituted to guide the paper 18 by the one paper guiding member 30 and further, the guiding surface 32 is formed on the rear surface side of the paper guiding member 30. The construction is simplified in this way and since the friction resistance of the paper guiding member 30 arises only on one surface of the paper 18, the paper 18 is smoothly transported.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a transfer device used in an electrophotographic image forming apparatus, and particularly relates to a transfer material guide member for guiding a transfer material such as paper to a transfer position. This invention relates to an improved transfer device.

In recent years, image formation has been developed in which an electrostatic latent image is formed on an image bearing member such as a photoreceptor drum, this is developed, and this image is transferred to a transfer material such as paper using a transfer device. The device has been widely put into practical use. Generally, in the transfer device used in this image forming apparatus, a conveyance mechanism is provided upstream of the photoconductor drum, and a conveyance mechanism is provided between the conveyance mechanism and the photoconductor drum to guide the paper to the transfer position of the photoconductor drum. A paper guide member is provided for this purpose.

Conventionally, as a transfer device equipped with this paper guide member, there is one disclosed in, for example, Japanese Patent Application Laid-open No. 10767/1983. In this transfer device, the paper guide member is
It is composed of a pair of guide members that are vertically opposed to each other.

``Problem to be Solved by the Invention'' However, in this conventional transfer device, the paper guided by the paper guide member is subject to frictional resistance between the guide surfaces of the two members, and the paper is not smoothly conveyed to the paper sheet. There wasn't. Furthermore, both sides of the paper become electrically charged due to friction.
Floating toner from the underside developing roller adheres to the paper, making it easy for the paper to become smudged. For this reason, antistatic measures are required for the paper guide member, but antistatic measures must also be applied to the guide member on the back side, which is unrelated to the transfer surface of the paper, which makes the structure complex and significantly increases costs. It had become.

The present invention has been made in view of such problems, and its purpose is to reduce the frictional resistance between the transfer material guide member and the transfer material, and to enable smooth conveyance of the transfer material.
It is an object of the present invention to provide a transfer device that has a simplified structure, can significantly reduce costs, and can obtain good transferred images.

A transfer device according to claim 1 includes an image carrier having a transfer position, a conveyance mechanism that sends out a transfer material obliquely upward, and a communication mechanism between the conveyance mechanism and the image carrier. A transfer material guide member is provided between the transfer material guide member and has a guide surface on the lower surface thereof, and guides the transfer material to the transfer position along the guide surface. Further, in the transfer device according to claim 2,
The transfer material guide member is formed by forming an insulating layer on the surface of a conductive substrate, and uses the surface of this insulating layer as a guide surface. Further, in the transfer device according to the third aspect of the present invention, at least a portion of the insulating layer of the transfer material guide member protrudes from the end portion of the conductive substrate on the image carrier side. Further, in the transfer device according to the fourth aspect of the present invention, the transfer material guide member is formed of a conductive member and is grounded via a resistor.

With such a configuration, in the transfer device according to the first and fourth aspects, the structure is simplified since the transfer material is guided by one transfer material guide member. Furthermore, since frictional resistance occurs only on one side of the transfer material, the transfer material can be conveyed smoothly.

Furthermore, a guide surface is formed on the lower surface side of the transfer material guide member,
Since the transfer material is guided along this guide surface, the transfer material can be stably supplied to the transfer position of the image carrier. In particular, in the transfer device according to claim 2, since the frictional resistance between the transfer material and the transfer material guide member can be significantly reduced, the transfer material can be conveyed even more smoothly and the charging caused by friction can be reduced. This can be reduced, and moreover, it is possible to prevent the occurrence of so-called transfer omissions and obtain a good transferred image. Further, in the transfer device according to the third aspect, it is possible to prevent so-called floating toner from adhering to the transfer material.

"Example" Hereinafter, the present invention will be described in detail with reference to the drawings.

Overall Structure of Image Forming Apparatus FIG. 3 shows a schematic structure of an electrophotographic image forming apparatus using a transfer device according to an embodiment of the present invention.

In this image forming apparatus, a photosensitive drum 11 as an image carrier is uniformly charged by a charging corotron 13 attached to a PC cartridge 12, and then an electrostatic latent image is formed by an optical R14 of a laser scanning device or the like. It is formed. This electrostatic latent image is developed as a toner image by a developing bias applied by a developing roller 16 attached to a toner car IJ 15. On the other hand, the paper 18 housed in the paper tray I7 is taken out one by one by a peeling mechanism such as a half-moon roller 19, and is taken out from the paper tray 17 by a conveyance roller
A conveyance roller 21a is used to align the leading edge of the paper 18 and the leading edge of the image via folding conveyance units such as 0a and 20b.
, 21b, and the tip comes into contact with them and temporarily stops. After that, these conveyance rollers 218
An electromagnetic clutch (not shown) that controls the rotation of 121b is driven. As a result, the paper 18 is transferred to the paper guide member 3 which will be described later.
Transfer position A of the photosensitive drum 11 along the guide surface 32 of
It is transported at a stable speed toward Then, a high voltage is applied to the wire of the transfer corotron 22 at the timing when the leading edge of the paper 18 enters the transfer corotron 22 provided near the transfer position of the photosensitive drum 11. As a result, the toner image developed on the photosensitive drum 11 is transferred to the paper 18. Further, the paper 18 on which the toner image has been transferred is charged from its back side by a charge eliminating member 23 disposed downstream of the transfer corotron 22 and peeled off from the photoreceptor drum 11 . is guided to the fixing section 26 along. Fixing section 26
is composed of a heating roller 26a and a pressure roller 26b. The heating roller 26a is controlled to a constant high temperature, and the paper 18 is heated between these rollers 25a and 26b.
The upper toner image is fused to paper 18.

The paper 18 on which the toner image has been fixed is transferred to ejection rollers 27a, 27b or ejection rollers 28a, 28b depending on its purpose.
With the printed surface facing downwards or upwards, exit the outlet 29.
a, 29b and stored in a paper discharge tray (not shown).

FIG. 1 shows the structure of a transfer device in this image forming apparatus. In the figure, a pair of conveyance rollers 21a
, 21b are so-called registration rollers,
One conveyance roller 21a is made of metal such as stainless steel, and the other conveyance roller 21b is made of an elastic member such as rubber. These conveyance rollers 21a, 21b are springs 21C.
The paper is pressed against each other, thereby applying paper conveyance force. Among the conveyance rollers 21a and 21b, the lower conveyance roller 21b is the same as the upper conveyance roller 21a.
It is located downstream (in the paper conveyance direction) from paper 1.
8 is sent out diagonally upward. A paper guide member 30 for guiding the paper 18 is disposed between these transport rollers 21a, 21b and the photosensitive drum 11. Paper guide member 30 and transfer corotron 22
A roller 31 for pressing the paper 18 against the surface of the photoreceptor drum 11 is provided between the photoreceptor drum 11 and the photoreceptor drum 11 .

This roller 31 is formed by forming a rubber layer on the surface of a cylindrical metal body, and is supported on the upper part of the transfer corotron 22, and the metal body is grounded through a resistor R of 100 MΩ.

The paper guide member 30 is composed of a conductive base 30a and an insulating layer 30b adhered to the lower surface of the conductive base 30a. A guide surface 32 is formed on the surface of this insulating layer 30b, and the paper 18 is guided to the photosensitive drum 11 along this guide surface 32.
It is designed to guide the user in the direction of the transfer position. Note that the transfer position A is set slightly upstream from the lowest end of the photosensitive drum 11.

The conductive base 30a of the paper guide member 30 is formed of metal, for example iron, into a plate shape. In addition, this conductive substrate 3
0a is grounded. On the other hand, the insulator layer 30b is made of an insulating resin such as polyethylene terephthalate (hereinafter referred to as PET). ), and its film thickness is, for example, approximately 0.1 mm. This PET has a volume resistivity of 1016 Ω·crn and a frictional resistance of 0.18. The insulator layer 30b is the photosensitive drum 1 of the conductive base 30a.
The projecting portion 33 protrudes from the end of the first side by about Q, 5 mm, and this protruding portion 33 prevents the paper 18 from contacting the conductive substrate 30a, and also prevents floating toner falling from the developing roller 16 from adhering to the paper 18. It is designed to prevent Further, the end of the paper guide member 30 on the side of the photoreceptor drum 11 is slightly bent in the direction of the transfer position A of the photoreceptor drum 11, and the paper 18 is guided to the transfer position A.

In the transfer device of this embodiment having such a configuration, the paper 18 is given a transport force by the transport rollers 21a and 21b, and is transported to the transfer position A of the photoreceptor drum 11 via the paper guide member 30. . Here, lower conveyance roller 2
1b is located on the downstream side of the upper conveyance roller 21a, the leading edge of the paper 18 is directed diagonally upward to the paper guide member 3.
0, and is guided along the guide surface 32 of the paper guide member 30 to the transfer position.

In this transfer device, the paper 18 is guided by one paper guide member 30, so the number of parts is reduced to half compared to conventional transfer devices, and the structure is significantly simplified. Furthermore, since the frictional resistance of the paper guide member 30 occurs only on one side (transfer surface) of the paper 18, the paper
8 is carried out smoothly.

Further, a guide surface 32 is formed on the lower surface side of the paper guide member 30, and a bent part 34 in the shape of a letter 34 is formed at the tip of this guide surface 32, so that the paper 18 can be kept at a fixed transfer position. It can be stably guided to. In addition, with such a configuration, there is no risk of damaging the photoreceptor drum 11 because it enters from a direction that is less susceptible to resistance against the curvature of the photoreceptor drum 11. That is, if the paper guide member 30 is configured to guide the paper 18 on the upper surface side, the leading edge of the paper 18 may swing when the paper 18 enters the photoreceptor drum 11, resulting in an incorrect transfer position. It becomes stable. In addition, the photosensitive drum 11
Since it enters at an angle that is susceptible to resistance against the curvature of , there is a risk of damaging the photoreceptor drum 11 . On the other hand, a guide surface 3 is provided on the lower surface side of the paper guide member 30.
In the case of the transfer device of this embodiment in which the number 2 is formed, such a problem is eliminated.

Furthermore, in the transfer device of this embodiment, the conductive substrate 30
The paper guiding member 30 is formed by adhering an insulating layer 30b formed of PET to the lower surface side of the sheet a. With such a configuration, since the frictional resistance of the insulating layer 30b is small, the paper 18 can be transported smoothly. In addition, the paper guide member 3
When the paper 18 is guided by the conductive substrate 30a
An electric field is formed between the insulating layer 30b and the paper 18.

Therefore, even if a charge (positive charge) is generated due to friction between the paper 18 and the insulating layer 18, it is canceled out by the charge (negative charge) generated on the grounded conductive base 30a. As a result, the paper 18 is not charged. Therefore, image blurring, so-called fan blur, is improved.

Furthermore, since the insulating layer 30b is not charged, it is less susceptible to the influence of charges greater than those required for transfer of corona discharge on the transfer corotron 22 side. Therefore, so-called transfer failure does not occur, and therefore good transfer is performed.

Further, since the insulating layer 30b is provided with a protrusion 33, which protrudes from the end of the conductive substrate 30a on the photoreceptor drum 11 side, floating toner from the developing roller 16 is present. Also, it does not stick to the paper 18 in a concentrated manner.

Generally, in order to obtain a good transferred image, it is desirable to move the rollers 31 on the transfer corotron 22 together with the paper guide member 30 as close to the transfer position A of the photosensitive drum 11 as possible. Transfer position A is the roller 31 and paper guide member 30
If the rollers 31 and paper guide member 30 are too far away from the photoreceptor drum 11, the rear end of the paper 18 will be flipped up at the moment it leaves the paper guide member 30. As a result, the paper 18 being transferred momentarily deviates from the ideal path and vibrates, resulting in the so-called defect phenomenon (a phenomenon where a black band appears in a horizontal line).
An image defect called . In the transfer device of this embodiment, the roller 31 is supported above the transfer corotron 22, and the amount of floating toner adhering to the paper guide member 30 can be reduced as described above. 31 can be brought close to the transfer position to such an extent (within 4 mm) that no defect phenomenon occurs, and a good transferred image can be obtained.

When the paper 18 was actually conveyed and transferred by the transfer corotron 22, floating toner did not adhere to the paper 18 and no stains were generated. Further, even in a low humidity state where stains are likely to occur, no stains were generated on the paper 18, and even in high humidity conditions, no transfer omissions occurred, and a good transferred image was obtained.

As the insulator layer 30b, PET as in the above embodiment is preferable, but any material having similar characteristics can be used as well. For example, polycarbonate
High-density polyethylene, AB]it resin, vinyl chloride, polypropylene, polyacetal, etc. can all be used because they have a volume resistivity of 1 x 101S to 1 x 10'6 Ω·cm. In particular, high-density polyethylene and vinyl chloride, which have frictional resistance close to that of PET, are preferred.

In addition, 0.1m for ABS resin and polyacetal
Since there is no sheet-like material of m, the conductive substrate 3 (
It is necessary to form an insulator layer 30b by coating on la.

FIG. 2 shows another embodiment of the invention.

In this embodiment, the paper guide member 40 is made of metal, for example, iron, and a guide surface 41 is formed on the lower surface of the paper guide member 40, and the tip end on the photoreceptor drum 11 side is bent. It is bent into a letter shape to form a bent portion 42 . This paper guide member 40 and the roller 31 are grounded through a resistance R of 100 MΩ. The rest of the configuration is the same as the embodiment shown in FIG. 1, so a description thereof will be omitted.

In this transfer device, the paper 18 sent out from the transport roller 21a121b is guided to the transfer position 1tA of the photosensitive drum 11 along the guide surface 41 on the lower surface side of the paper guide member 40.

In this transfer device, like the transfer device in FIG.
Since the paper 18 is guided by two paper guide members 40, the number of parts is reduced by half compared to the conventional transfer device, as in the embodiment shown in FIG.
Anti-static measures such as high-resistance grounding using a neutralizing blank or the like and applying a bias are also eliminated, and the structure is significantly simplified. Further, since the frictional resistance of the paper guide member 40 is generated only on one side (transfer surface) of the paper 18, the paper 18 can be conveyed smoothly. Further, since a guide surface 41 is formed on the lower surface side of the paper guide member 40, the paper 18 can be stably guided to a fixed transfer position, and resistance against the curvature of the photoreceptor drum 11 can be reduced. Since it enters from a direction where it is difficult to receive, there is no risk of damaging the photoreceptor drum 11. Also, in the transfer device of this embodiment, the roller 31
Since the transfer corotron 22 is supported above the transfer corotron 22, the paper guide member 30 can be moved closer to the transfer position A than in the past, and a good transferred image can be obtained.

"Effects of the Invention: As explained above, according to the transfer device according to claims 1 and 4, since the transfer material such as paper is guided by one transfer material guide member, the structure is extremely simple. This makes it possible to significantly reduce costs.Furthermore, since frictional resistance occurs only on one side of the transfer material, the transfer material can be conveyed smoothly.Moreover, there is a guide surface on the lower surface of the transfer material guide member. Since the transfer material is guided along this guide surface, the transfer material can be stably supplied to the transfer position of the image carrier, and there is no risk of damaging the image carrier. It disappears.

Further, according to the transfer device according to claim 2, since the transfer material guide member is configured by forming an insulating layer on the surface of the conductive substrate, there is a frictional resistance between the transfer material and the transfer material guide member. This makes it possible to reduce the transfer material, thereby making it possible to convey the transfer material even more smoothly, reducing electrification caused by friction, and preventing the occurrence of so-called transfer omissions, thereby making it possible to obtain a good transferred image.

Furthermore, according to the transfer device according to claim 3, a part of the insulating layer of the transfer material guide member is made to protrude from the end of the conductive substrate on the image carrier side, so that so-called floating toner can be transferred to the transfer material. It is possible to prevent the adhesion of paper, prevent the occurrence of paper stains, and obtain a good transferred image.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of the vicinity of a transfer device according to an embodiment of the present invention, FIG. 2 is a schematic diagram of the vicinity of a transfer device according to another embodiment of the present invention, and FIG. 3 is an embodiment of the present invention. 1 is a schematic configuration diagram of an image forming apparatus using a transfer device according to an example. 11... Photosensitive drum, 21a, 21b... Conveyance roller, 22...
...Transfer corotron, 30.40...Paper guide member, 30a...
...Conductive substrate, 30b...Insulator layer, 32. 1...Information surface.

Claims (1)

[Scope of Claims] 1. An image carrier having a transfer position, a conveyance mechanism that sends out the transfer material obliquely upward, and an image carrier disposed between the conveyance mechanism and the image carrier and on the lower surface thereof. a transfer material guide member having a guide surface on a surface thereof and guiding the transfer material to the transfer position along the guide surface. 2. The transfer device according to claim 1, wherein the transfer material guide member is formed by forming an insulating layer on the surface of a conductive substrate, and uses the surface of the insulating layer as a guide surface. 3. The transfer device according to claim 2, wherein at least a portion of the insulating layer of the transfer material guide member protrudes from an end of the conductive substrate on the image carrier side. 4. The transfer device according to claim 1, wherein the transfer material guide member is formed of a conductive member and is grounded via a resistor.