JP2001315993A - Paper carrying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the stress given to paper carried in a paper carrying passage in the lateral direction of the paper by an upstream carrying roller device while sliding the paper on a guide plate to prevent the wrinkle of the sheet in the nipping by a downstream carrying roller device. SOLUTION: A guide plate 30 arranged in the paper carrying passage between two carrying rollers 6 and 21 has a number of ribs 31 protrusively provided so as to extend in the advancing direction of the paper, and the ribs 31 are obliquely provided on both sides to the center part of the paper carrying passage. The paper to be carried so as to slide on the ribs 31 is nipped and carried by the downstream carrying roller in the state where the effect of extending in the lateral direction is imparted to the paper to solve the stress imparted by the upstream carrying roller device 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper transport device provided in an electrophotographic recording apparatus or the like, and relates to a paper transport device capable of transporting a paper while expanding in a width direction by guiding the transported paper by ribs. Related to the device.

[0002]

2. Description of the Related Art In an image recording apparatus using an electrophotographic system, a toner image is formed on a photosensitive drum, and the toner image transferred onto paper is fixed through a fixing device and discharged as recording paper. I have. In the image forming apparatus, information obtained by reading an image of a document on a photosensitive drum is directly irradiated with reflected light or converted into laser light and irradiated to form an electrostatic latent image. Next, the toner image is transferred to paper by using a means for attaching a toner to the electrostatic latent image to make it a visible image, and the image is fixed and discharged as a copy.

In the above-described image forming apparatus, a copying machine, a facsimile machine, or a paper transport system of a printer, a paper transported one by one from a paper tray is placed in a paper transport path provided with means for guiding the paper by a guide plate. Are transported by transport roller devices arranged at predetermined intervals. Then, the registration roller is temporarily stopped by a registration roller provided immediately before the position where the toner image is transferred from the photosensitive drum, and the registration roller is driven in accordance with the position of the toner image to be formed on the photosensitive drum, and is transferred to the transfer unit. To guide the paper accurately.

[0004]

The guide plate disposed in the paper transport path uses a plate-shaped member made of sheet metal or plastic. However, when the guide plate is a flat plate, the contact resistance with the paper is low. However, there is a disadvantage that the frequency of occurrence of paper jam is large. Therefore, in order to reduce such transport resistance, a large number of ribs are provided on the paper guide surface of the guide plate in parallel with the transport direction to improve the guideability of the paper. Further, in the paper feeding path, in the paper introduction part to the image recording part or the reading part, it is necessary to suppress flapping of the paper passing through the rib part for recording or reading the image. For this purpose, in the conventional guide plate, measures are taken to increase the arrangement density of ribs in the sheet introduction portion and the like, and to reduce the interval between the upper and lower guide plates for guiding the sheet. However, it is difficult to determine the positional relationship of the ribs in order to control and guide the paper according to various paper widths.
There remains a problem that it is difficult to prevent the occurrence of jam.

An object of the present invention is to solve the problem of the guide plate provided in the paper transport path, and to provide a paper transport in which ribs are arranged so that a guiding action can be easily performed on paper of various sizes. The present invention relates to a guide plate of an apparatus.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a sheet conveying device for conveying a sheet along a guide plate by a conveying roller device disposed in a sheet conveying path. The invention according to claim 1 of the present invention is characterized in that the guide plate is provided with a number of ribs in the paper moving direction, and the ribs arranged on the guide plate are arranged in the width direction of the paper toward the downstream side in the paper transport direction. It is characterized by being provided so as to be gradually expanded. Therefore, it is possible to guide the paper smoothly without causing fluttering of the paper passing through the paper transport path.

The invention according to claim 2 is characterized in that the ribs arranged on the guide plate are provided at symmetrical positions with respect to the center line of the guide plate in the conveying direction. With the above-described configuration, a paper guide that does not easily damage the paper guided by the guide plate can be configured.

The invention according to claim 3 is characterized in that the guide plate provided with the ribs at symmetrical positions is applied between a registration roller device and a recording section in a recording apparatus or an intrusion path to the registration roller device. I do. Therefore, the guideability of the sheet to the recording unit is improved, and it is possible to prevent the occurrence of recording unevenness and reading unevenness due to paper conveyance.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a sheet conveying device according to the present invention. In the example shown in FIG. 1, between two transport roller devices 5, 5a arranged in a paper transport path,
This shows a configuration of a guide plate for guiding a sheet. The guide plate 30 has ribs 31, 31a,... Is provided so as to expand toward the downstream side of the. When the guide plate is a plate member made of resin, the ribs 31 provided on the guide plate 30 are integrally formed so that a large number of ribs project obliquely on the surface of the guide plate 30. be able to.

It is also possible to affix the guide plate 30 with separately formed ribs 31.
For example, when the guide plate is formed of a sheet metal, it is assumed that the paper guide surface of the guide plate is distorted by performing press working. By attaching the separately formed rib member to the surface of the guide plate, the plate body can be configured so as not to be distorted. When the guide plate is integrally formed of resin or the like, a gentle inclined guide surface is provided at an end of the rib 31 so that the leading end of the sheet is not caught.

In the example shown in FIG. 1, the transport roller device disposed upstream of the paper transport path 4 is such that the transport roller device 5 such as a paper feed roller has a narrow width, When the device 5a is long, corresponding to the width of the paper transport path, it is particularly effective when transporting paper between two transport roller devices. That is, in the upstream portion of the paper transport path, the transport action is applied at the central portion of the paper by the narrow transport roller device 5, so that a large stress is applied at the central portion in the width direction of the paper. When the paper is nipped by the wide transport roller device 5a at the downstream portion in a state where the local stress is still applied to the central portion of the paper, the transport action is applied in the entire width direction of the paper. It is assumed that wrinkling or the like causes wrinkles to be formed on the sheet.

In order to prevent the above-mentioned inconvenience from occurring, in this embodiment, a large number of ribs are formed on a guide plate on which the paper slides between the conveying roller devices, and the ribs are formed in the width direction of the paper. It is arranged in a state inclined toward the outside of the. Then, even when the central portion of the paper is strongly stressed by the narrow conveying roller device, the paper sliding on the guide plate slides on the ribs 31 to eliminate local stress. I am trying to do it. That is, when the paper slides on the guide plate, the obliquely provided ribs 31... Impart an action of expanding the paper in the width direction. By sliding, while gradually eliminating the stress that causes wrinkles, it is nipped by the transport roller device 5a in the downstream portion,
The paper can be transported in a normal state.

FIG. 2 shows an example in which the photosensitive drum 21 and the conveying roller device as the registration roller device 6 are moved between
This shows the configuration of a guide plate provided on the lower surface of the paper transport path. The guide plate 30 is provided with the same oblique ribs 31 as in the example of FIG. I have. For example, the sheet is temporarily stopped between the registration roller device 6 and the photosensitive drum 21 in a state where the sheet is nipped by the registration roller device, and then is sent out in synchronization with the toner image formed on the photosensitive drum 21. When the leading end of the sheet reaches the image transfer position from the photosensitive drum, the toner image set on the photosensitive drum is transferred. However, in a state where the paper sent out by the registration roller device 6 is still locally stressed, when the paper reaches the photosensitive drum, the paper does not uniformly contact the photosensitive drum. When the toner image is transferred to a sheet, there is a problem that the image is distorted.

Therefore, in the example shown in FIG. 2, the sheet is transferred from the registration roller device 6 disposed upstream of the sheet transport path to the photosensitive drum 21 with respect to the guide plate 30 on which the lower surface of the sheet slides. A large number of ribs 31 inclined in the expanding direction are arranged in parallel. Then, the sheet sent out from the registration roller device 6 is
1. While sliding in the direction of
Apply friction to spread the paper toward both sides in the width direction of the paper. Therefore, by applying the action of expanding the sheet to both sides, it is possible to make normal contact with the photosensitive drum 21 without leaving local stress on the sheet in contact with the photosensitive drum 21.

As shown in FIGS. 1 and 2, the paper is slid on the paper conveyed in the paper conveyance path by the conveyance roller device in order to eliminate the stress in the width direction applied by the conveyance roller device. By providing a large number of ribs on the guide plate to be applied and applying frictional force in the direction of expanding the paper,
It is possible to carry out the sheet conveying operation in a favorable state.
By arranging a large number of ribs oblique to the center of the paper transport path toward the outside in the traveling direction of the paper, the paper sliding on the ribs is expanded toward both sides in the width direction. With such a force applied, the sheet is nipped by the transport roller device at the downstream portion in a state where the stress causing the wrinkle is eliminated.

The guide plate provided with the ribs spread outward can be arranged at an arbitrary position on a sheet conveying path of an image forming apparatus or the like. If it is applied to a part where the paper slides strongly, its effectiveness can be exhibited. Further, a sheet which is greatly affected by a stress applied to the sheet, such as between an upstream portion of the photosensitive drum and a conveying roller device or an upstream portion of a reading unit of an image reading device. In the transport path,
It is preferable to arrange a guide plate provided with the rib. further,
In the transport roller device disposed in the paper transport path, in addition to arranging the rollers in the entire width direction of the paper transport path, only one narrow roller such as a paper feed roller is disposed, and the center of the paper is transported. In some cases, the conveying action by the rollers may be provided. A large local stress is applied to the sheet on the upstream side between the narrow roller and the wide roller on the downstream side, and the entire width is nipped by the transport roller device on the downstream side. Since this is considered to be a cause of wrinkles, the stress can be eliminated by the guide plate, so that the sheet can be conveyed satisfactorily.

The guide plate configured as described above is similar to the guide plate shown in FIG.
Can be arranged in the paper transport path of the image forming apparatus as shown in FIG. In the image forming section of the image forming apparatus 1 shown in FIG. 3, a sheet feeding section from a sheet feeding tray 2 is provided at a lower portion of the apparatus, and an image forming section using an electrophotographic method is arranged at an upper portion. In the paper feed section, paper is fed one by one by a paper feed roller 3 arranged on a paper feed tray 2,
The sheet is conveyed by the conveying roller devices 5 and 6 and sent out toward the toner image transfer section. In the paper transport path, as shown in the examples of FIGS. 1 and 2, guide plates 30 and 30a having a large number of ribs provided diagonally are arranged.
By sliding the paper on the guide plates 30 and 30a between the transport roller devices, it is possible to nip the downstream transport roller device in a state where the stress applied by the upstream transport roller is eliminated. Further, in the paper transport path 4 of the image forming apparatus 1 shown in FIG. 3, a plurality of transport roller devices can be arranged in addition to the illustration, and a guide plate for guiding a paper between arbitrary transport roller devices is provided. In contrast, by exerting the stress relieving action of the rib, it is possible to prevent the created copy from wrinkling,
Copy quality can be improved.

An image forming section arranged above the image forming apparatus 1 is provided with a combination of a developing unit 10 and a photosensitive unit 20. In the developing unit 10 arranged in combination with the photoconductor unit 20, the toner contained in the toner containing section 11 is sent out toward the supply roller 13 while being stirred by the agitator 12, and is rubbed with the supply roller 13. As described above, the toner is applied as a thin layer to the surface of the developing roller 14 while charging the toner between the developing roller 14 and the developing roller 14 which rotates in the counterclockwise direction in the drawing. The toner adhered to the surface of the developing roller 14 is formed as a thin layer having a certain thickness by a blade member, and the toner adheres to the electrostatic latent image of the photosensitive member at a portion where the toner contacts the photosensitive member 21. The image is visualized as a toner image.

A transfer roller 25 for transferring the toner image formed on the photoreceptor 21 to a sheet is disposed on the photoreceptor unit 20 arranged in combination with the developing unit 10. Around the photosensitive member 21, a memory removing member 24 composed of a transfer roller 25 and a brush, a charging roller 23 composed of a brush roller, and a writing device 22 are arranged in accordance with the rotation direction of the photosensitive member 22.
Is arranged. Then, the photosensitive member 21 is uniformly charged by a charging unit 23 and irradiated with light of image information from a writing unit 22 to form an electrostatic latent image. The toner adhering to the surface of the developing roller 14 is formed as a thin layer having a certain thickness by a blade member.
At a portion in contact with 1, the toner adheres to the electrostatic latent image on the photoconductor, and is visualized as a toner image. The toner image formed on the photoconductor is composed of a photoconductor 21 and a transfer member 2.
5, the transfer is performed by applying a predetermined voltage to the transfer member.

The sheet carrying the toner image is conveyed toward the fixing device 7, and is heated by a heat roller 7a and a pressure roller 7b.
And is discharged toward the discharge tray by the discharge roller device 8. The image forming apparatus 1
In the writing information supplied to the writing member 22,
Image information from an image reading apparatus (not shown) provided in combination with the image forming apparatus 1 or a digital signal received by facsimile through a telephone line is used to cause the LED element of the writing member 22 to emit light in a dot-like manner. The image information is written on the photoconductor. In the image forming unit of the image forming apparatus 1, after the toner image is transferred from the photoconductor to the paper without providing a cleaning device for the photoconductor 21, the remaining toner memory is disturbed to reduce the adhesive force. It is configured as a so-called cleaner-less type image forming apparatus that is weakened and collected in a developing unit and reused.

[0021]

Since the apparatus according to the present invention is constructed as described above, by providing a large number of ribs in the moving direction of the sheet on the guide plate, the sheet passing through the sheet conveying path may flap. The guide can be guided smoothly to the downstream transport roller device while eliminating the stress applied by the upstream transport roller device. Further, since the ribs arranged on the guide plate are provided at symmetrical positions with respect to the center line in the transport direction of the guide plate, a paper guide which is hardly damaged by the sheet guided by the guide plate is configured. Can be. Further, the guide plate provided with the ribs at symmetrical positions,
It can be applied to a registration roller device and a recording unit in an electrophotographic recording device, or to an entrance path to a registration roller device, and can be applied to a recording unit disposed downstream of a sheet conveyance path, a reading device, or the like. The sheet guideability is improved, and it is possible to prevent the occurrence of recording unevenness, reading unevenness, and the like due to paper conveyance.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a configuration of a paper transport path.

FIG. 2 is an explanatory diagram of a sheet conveying device different from FIG.

FIG. 3 is an explanatory diagram of an example of an image forming apparatus to which the present invention can be applied.

[Explanation of symbols]

1 image forming apparatus, 2 paper cassette, 3
Paper feed roller, 4 paper transport path, 5.6 transport roller device, 7 fixing device, 8 discharge roller device,
Reference Signs List 10 developing device, 11 toner container, 12 agitator, 13 supply roller, 14 developing roller, 20 photoconductor unit, 21 photoconductor drum, 22 writing device, 23 charging roller, 2
4 memory removal roller, 25 transfer roller, 30
Guide plate, 31 ribs.

Claims (3)

[Claims] 1. A sheet transport device for transporting a sheet along a guide plate by a transport roller device disposed in a sheet transport path, wherein the guide plate is provided with a plurality of ribs in a sheet moving direction. The paper transporting device is characterized in that the ribs arranged in the paper transporting device are provided so as to gradually expand in the width direction of the paper toward the downstream side in the paper transporting direction. 2. The sheet conveying device according to claim 1, wherein the ribs arranged on the guide plate are provided at symmetrical positions with respect to a center line of the guide plate in the conveying direction. 3. The printing apparatus according to claim 1, wherein the guide plate provided with the ribs at symmetrical positions is applied between a registration roller device and a recording unit in a printing apparatus, or an intrusion path to the registration roller device. 3. The paper transport device according to 2.