JPH0476895B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a sheet conveyance system that conveys a sheet based on the rotation of a pair of rollers in an image forming apparatus that forms an image on a sheet, such as a copying machine or a laser beam printer. The present invention relates to an apparatus, and more particularly to a sheet conveying apparatus capable of releasing pressure between a pair of rollers.

(B) Prior Art In general, a sheet conveying device, for example, a sheet conveying device of a copying machine equipped with a sheet re-conveying path used when performing double-sided copying and multiple copying, is disclosed in Japanese Patent Application Laid-Open No.
As shown in Japanese Patent No. 95264, a discharge roller discharges sheets copied in an image forming section to a bin tray. An apparatus has been devised in which the apparatus is configured to be capable of forward and reverse rotation, and further has a sheet re-conveying path for conveying the copied sheet to the image forming section again in front of the pair of discharge rollers on the upstream side. In order to embody the sheet conveying device, a pair of registration rollers for correcting the lateral position of the sheet is disposed on the sheet re-conveying path so as to be movable in a direction perpendicular to the sheet conveying direction, and the discharge roller a sheet trailing edge detection sensor that detects the trailing edge of the sheet conveyed through the pair of rollers, near the pair of rollers;
It is also necessary to arrange a flapper that guides the sheet conveyed from the image forming section to a pair of discharge rollers or a sheet re-conveyance path.

When the double-sided copying mode of the copying machine is selected, the sheet copied on the front side in the image forming unit is conveyed onto the bin tray by the forward rotation of a pair of ejection rollers, and the trailing edge of the sheet is detected. When detected by the sensor, the discharge roller pair is reversely rotated, and the sheet is guided by the flapper and conveyed to the sheet re-conveyance path. Further, while the sheet is held between the pair of registration rollers on the re-transport path, its lateral position is corrected by movement of the pair of rollers, and the sheet is conveyed to the image forming section again by a signal from the copying machine main body.
The back side of the sheet is copied to complete double-sided copying. In addition, when the multiple copy mode of the copying machine is selected, the flapper is switched and the sheet copied on the front side in the image forming unit is conveyed to the sheet re-conveying path without passing through the ejection roller pair, and the flapper is Similarly, the lateral position of the sheet is corrected by a pair of registration rollers, and further conveyed to the image forming section again by a signal from the main body of the copying machine, the front surface of the sheet is copied, and multiple copying is completed.

(C) Problems to be Solved by the Invention Incidentally, the sheet re-conveying path is formed below the image forming section due to the arrangement of each device inside the copying machine main body, and further miniaturization of the copying machine is required. Because of the need to reduce the height of the copying machine main body, the distance between the image forming section and the sheet re-conveying path is made as small as possible, and the space becomes extremely narrow.

Therefore, since the pair of registration rollers in the sheet re-conveying path move in a direction perpendicular to the sheet conveying direction in order to correct the lateral position of the sheet, troubles such as paper jams often occur. Jamming becomes extremely difficult.

(d) Means for solving the problems The present invention aims to solve the above-mentioned problems, and for example, as shown in FIG.
A sheet conveying device that sandwiches a sheet between a pair of rollers 1 with one roller 1a facing the other roller and conveys the sheet based on the rotation of the pair of rollers, and the sheet is conveyed by the pair of rollers 1. A guide plate 2 is disposed to guide the sheet, and the guide plate is provided with fulcrum parts 5 and 6 whose fulcrum axes are perpendicular to the sheet conveyance direction, so that the guide plate can be opened in the direction of opening and vice versa. Based on the rotation in the opening direction C about the fulcrum of the guide plate or the rotation in the opposite direction A in conjunction with the opening movement of the other guide means 20, 40, The roller 1b is characterized by being provided with a separating means for separating the roller 1b and the roller 1a.

(E) Operation Based on the above configuration, when a trouble such as a paper jam occurs in the roller pair (registration roller pair) 1, when the guide plate 2 is rotated around the fulcrum part 5 or 6, the roller pair 1 The other roller 1b is separated from the one roller 1a, the pressure between the rollers of the roller pair 1 is released, and jamming can be easily performed.

(f) Examples Examples of the present invention will be described below with reference to the drawings.

As shown in FIG. 4, the copying machine U has a document table 7,
Light source 9, lens system 10, two cassettes 11,1
2, and a cylindrical photoreceptor 13 is disposed within the main body of the copying machine. Furthermore, the photoreceptor 13
Near the periphery, there are two developing devices 15 and 16 each containing toner of a different color, a cleaner 17 and a primary charger 19, and a transfer charger 21 and a separation charger 22 are located at the tip of the conveyance device 20. It is arranged. In addition, paper feed rollers 23 and 25 are arranged in the cassettes 11 and 12, respectively, and feed rollers 23 and 25, respectively.
6 and 27, and is guided to a pair of registration rollers 29. Further, a fixing device 30 is disposed at the rear end portion of the conveyance device 20, and a first flapper 31 and a second flapper 32 are disposed downstream of the fixing device 30, and a roller pair 33 is disposed downstream of the fixing device 30. A sheet trailing edge detection sensor 35 for detecting the trailing edge of the sheet discharged from the roller pair 33 is installed near the discharge roller pair 33. Also, the first flapper 3
1, the sheet re-conveying path 36 is branched and selected.
The re-conveyance path 36 is provided with a pair of conveyance rollers 37 and 39 and a pair of lateral registration rollers 1, which will be described later.
is communicated with.

As shown in detail in FIG. 2, the lateral registration roller pair 1 is configured such that an upper roller 1b is urged and resiliently contacted by a spring mechanism (not shown) to a lower roller 1a rotatably supported by a fixed member. A moving guide plate 2 having an upwardly inclined surface at its tip is rotatably connected to the roller shaft 1c of the upper roller 1b.
Supported. Further, the movable guide plate 2 has protrusions 5, 5 arranged at both lower ends near the upstream side of the upper roller 1b, and the protrusions 5, 5 abut against the fixed guide plate 4, so that the movable guide plate 2 is positioned and supported. Further, by the rotation of the movement guide plate 2 in the direction of arrow A, the upper roller 1b is rotated in the direction of arrow B using the projections 5, 5 as fulcrums against a spring mechanism (not shown), and the upper roller 1b is moved downward. It is separated from the roller 1a. Further, cam portions 6, 6 are arranged at both front ends of the moving guide plate 2 facing the roller shaft 1d of the lower roller 1a, and when the moving guide plate 2 rotates in the direction of arrow C (FIG. 3), cam part 6,
6 comes into contact with the lower roller shaft 1d, the upper roller 1b is rotated in the direction of arrow B using the cam parts 6, 6 as fulcrums, and the upper roller 1b is separated from the lower roller 1a.

Further, as shown in FIG. 1, the conveying device 20 having a large number of rollers is configured to be rotatable around a downstream roller shaft 20a, and is configured to be able to freely rotate around a downstream roller shaft 20a, and to lower the lower roller 29a of the registration roller 29 and its vicinity. The guide plate 40 is configured to be rotatable about an upstream rotation center 41, and furthermore, the upstream end of the lower guide plate 40 is placed and connected to the upstream end of the conveyance device 20. Therefore, when the conveyance device 20 is rotated in the direction of arrow D, the registration lower roller 29a
and the lower guide plate 40 are rotated, and the conveying device 2
0 is brought into contact with the upper end of the movable guide plate 2, and applies a rotational force to the movable guide plate 2 in the direction of arrow A.

Since the present embodiment has the above-described configuration, when the light source 9 moves, the document M placed on the document table 7 is irradiated by the light source 9, and the reflected light passes through the lens system 10 and is pre-charged by the charger 19. An image is formed on the uniformly charged surface of the photoreceptor 13 to form an electrostatic latent image, and as the photoreceptor 3 rotates in the direction of the arrow, the electrostatic latent image is transferred to the toner at the developing device 16 position. form an image. On the other hand, the sheets S loaded in the cassette 11 or 12 are sent to the paper feed roller 23 or 25, aligned with the toner image on the surface of the photoreceptor by the registration roller 29, and further transferred to the transfer charger 21. The toner image is transferred to the sheet surface. Further, the sheet S carrying the toner image is separated from the photoreceptor 13 by a separation charger 22, sent to a fixing device 30 by a conveyance device 20, and fixed there.

When the double-sided copy mode is selected, the sheet S fixed by the fixing device 30 is
The sheet is guided by the flapper 31 of the sheet, and is transported toward the outside of the main body of the copying machine U by the forward rotation of the pair of discharge rollers 33. At this time, the second flapper 32 is in a state of blocking the sheet conveyance path, but since the second flapper 32 is made of a light member and is supported rotatably in the direction of arrow F, it is difficult for the sheet S to pass through. Accordingly, it is pushed up by the leading edge of the sheet and is retracted from the sheet S, so that it does not become an obstacle to the passage of the sheet S. Furthermore, when the sheet S is conveyed by the forward rotation of the ejection roller pair 33 and the trailing edge of the sheet S is detected by the sheet trailing edge detection sensor 35, the ejection roller pair 33 is reversely rotated and the sheet S is transferred to the second The sheet is guided by the flapper 35 and the first flapper 31 and guided to the sheet re-conveyance path 36. Furthermore, the sheet S is conveyed forward by the stopped lateral registration roller pair 1 by the rotation of the conveyance roller pair 37, 39, and after the sheet S leading edge of the registration roller pair 1 abuts against the conveyance roller pair 37, 39. is stopped, and the sheet S is stopped in a state forming a loop in front of the pair of lateral registration rollers 1. Then, when a copy signal for the other side is transmitted from the copying machine main body, the pair of lateral registration rollers 1 is rotated, and with the pair of lateral registration rollers 1 biting the sheet S, the side edge of the sheet is The sheet S is moved in a direction perpendicular to the sheet conveyance direction until it is detected by an optical sensor that does not move, and the lateral position of the sheet S with respect to the conveyance direction is adjusted. Further, the sheet S is connected to the registration roller pair 29.
The toner image is transferred to the back surface (non-copied surface) of the sheet by the photoreceptor 13 and the transfer charger 21, etc. in the same manner as described above, and is further fixed by the fixing device 30. The sheet copied on both sides is discharged to the outside of the copying machine main body by a pair of discharge rollers 33.

Also, if multiple copy mode is selected,
The first flapper 31 is switched to the sheet re-conveying path 36 side, and the copied sheet S fixed by the fixing device 30 is guided by the first flapper 31 to the sheet re-conveying path 36 . Then, as in the case of double-sided copying described above, the lateral position of the sheet S is adjusted by the pair of lateral registration rollers 1, and the sheet S is further conveyed by the pair of registration rollers 29, and the sheet S is copied once. The second image is superimposed and copied on the same side. Further, after the multiple copied sheet is fixed in the fixing device 30, the first flapper 31 is switched to the discharge roller pair 33 side.
and is discharged to the outside of the copying machine main body by a pair of discharge rollers 33.

Next, jam handling when a trouble such as a paper jam occurs in the pair of lateral registration rollers 1 of the copying machine U will be described.

First, the jam processing in a state where the lateral registration roller pair 1 clamps the leading edge of the sheet will be described.
If a problem such as a paper jam occurs in this condition,
This trouble is detected by a signal transmitted from a paper jam detection device or safety device (not shown), and the copying machine U is stopped. Then, when the operator opens the front cover of the copying machine U and rotates the moving guide plate 2 in the direction of the arrow C about the shaft 1c as shown in FIG. The upper roller 1b is brought into contact with the shaft 1d, and as the guide plate 2 rotates, the upper roller 1b is raised in the direction of arrow B against a spring mechanism (not shown) using the contact portions of the cam portions 6, 6 as fulcrums. The sheet is separated from the lower roller 1a, and a gap h (h is larger than the thickness of the sheet) is generated between the upper roller 1b and the lower roller 1a. And the corresponding gap h
As a result, the leading edge of the sheet is easily removed from the pair of lateral registration rollers 1, and the jam processing is performed.

Next, jam processing will be described in a state where the leading edge of the sheet is held between the pair of registration rollers 29 and the trailing edge of the sheet is held between the pair of lateral registration rollers 1. If a trouble such as a paper jam occurs in this state, the trouble is detected and the copying machine U is stopped, as described above. Then, when the operator rotates a lever (not shown), the transport device 20
As shown in FIG.
b and the lower roller 29a are separated, and the leading edge of the sheet is easily removed from the pair of registration rollers 29. At the same time, by rotating the transport device 20 in the direction of arrow D,
The conveyance device 20 is brought into contact with the upper tip of the moving guide plate 2, and the moving guide plate 2 is rotated in the direction of arrow A using the protrusions 5, 5 as fulcrums. Roller 1b is lower roller 1a
A gap h is generated between the upper roller 1b and the lower roller 1a. Due to the gap h, the rear end of the sheet is easily removed from the pair of lateral registration rollers 1, and the jamming process is performed.

Note that in this embodiment, the explanation has been given regarding the release of the inter-roller pressure in the pair of lateral registration rollers 1 in the sheet re-conveying path 36, but the same effect can be obtained with any pair of rollers that have inter-roller pressure that clamps the sheet. Of course.

(G) Effects of the Invention As explained above, according to the present invention, a guide plate is provided to guide a sheet conveyed by a pair of rollers in which one roller faces the other roller, and forming a fulcrum part having a fulcrum axis in a direction perpendicular to the sheet conveyance direction on the guide plate,
Based on the rotation of the guide plate around the fulcrum,
Since the other roller and one roller are separated from each other, the pressure between the rollers can be easily released by simply rotating the guide plate, and problems such as paper jams caused by the roller pair can be avoided. Processing can be performed easily.

Further, since the guide plate can be rotated in the opposite direction in conjunction with the rotation of the other guide means to release the pressure between the rollers, jams can be easily handled over a wide range. In other words, the roller pair is configured to move around the fulcrum when the guide plate rotates in one direction, and also around the fulcrum when the guide plate rotates in the other direction. The method for releasing the pressure between the roller pairs can be selected depending on the paper jam position, and efficient jam processing can be performed in response to many cases of paper jams.

[Brief explanation of drawings]

FIG. 1 is a side view showing a sheet conveying device according to the present invention, FIG. 2 is a side view showing its roller pair and guide plate portion, and FIG. 3 is a side view showing a state in which the guide plate is rotated in FIG. 4 are side views of a copying machine to which the present invention is applied. 1...Roller pair (horizontal registration roller pair), 1a...
Lower roller, 1b...Upper roller, 2...Guide plate (moving guide plate), 2'...Fixed guide plate, 5, 6...Fully point part (5...Protrusion part, 6...Cam part), 20, 40...Other guides Means (transport device, lower guide plate), U... copying machine.

Claims (1)

[Scope of Claims] 1. A sheet conveying device that sandwiches a sheet between a pair of rollers in which one roller is opposed to the other roller, and conveys the sheet based on the rotation of the pair of rollers, comprising: A guide plate is arranged to guide the sheet to be conveyed, and a fulcrum part having a fulcrum axis in a direction perpendicular to the sheet conveyance direction is formed on the guide plate, so that the guide plate can be opened in the direction of opening and vice versa. When the guide plate rotates in the opening direction about the fulcrum part or rotates in the opposite direction in conjunction with the opening movement of the other guide means, the other roller and the one roller are rotated. A sheet conveying device including a separating means for separating rollers.