JPH09216750A - Sheet material carrying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably carry a sheet material with a belt by certainly sucking the sheet material using a fan regardless of its size. SOLUTION: A slide valve 31 is opened and closed according to the size and position of a carried sheet material 35. When the sheet material 35 passes through above the opened slide valve 31, a sucking force is generated through the suction hole 33 of a carrying belt 34, and the sheet material 35 is fixed onto the carrying belt 34. In this case, only the slide valve 31 under the sheet material 35 is opened. The sucking force therefore acts only on the lower side of the sheet material 35, and the seat material 35 is fixed onto the carrying belt 34, and stable carrying ability is displayed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet material conveying apparatus suitable for conveying a sheet material in the image forming apparatus main body.

[0002]

2. Description of the Related Art Conventionally, in order to convey a sheet material at a stable and high speed as the speed of an image forming apparatus increases, FIG.
Such a transport device has been proposed.

FIG. 7 (a) is a top view of the above-mentioned transfer device. The transport device includes a transport belt 51, and the transport belt has a suction hole 52. A duct 53 is provided on the lower side of the conveyor belt, and the air sucked through the suction holes is used for the duct 5
3 and is discharged to the outside of the apparatus by the fan 54. As a result, the conveyed sheet material 55 is sucked and fixed on the conveyor belt and can be conveyed at a stable speed without slipping on the conveyor belt.

[0004]

However, in the above-mentioned conventional example, when a small-sized sheet material is conveyed, since it does not reach the sheet material, a suction hole through which air can freely escape occurs.
In addition, since the suction holes are completely free to pass air between the sheet materials, the suction force at the portion where the sheet material is sucked is much weaker than when conveying a large sheet material. Become. Further, due to the decrease in the suction force, if an external force is applied to the sheet material even when the image is formed on the sheet material in the image forming apparatus, a transfer deviation occurs or the sheet material enters the fixing device. At that time, the sheet material is peeled off from the conveyor belt, and the sheet material vibrates, causing problems such as disturbance of the transferred image, curling of the sheet material, and wrinkles.

Therefore, the first object of the present invention is to eliminate the variation in the suction force of the sheet material due to the difference in size, and the second object is to ensure the transfer of the image to the sheet material by the reliable suction. The third purpose is to prevent vibration of the sheet material by reliable suction and realize stable conveyance of the sheet material.

[0006]

In order to achieve the above object, the present invention is characterized by having a mechanism for varying the suction range in a direction perpendicular to the sheet material conveying direction, and the present invention is a sheet material. It is characterized by having a mechanism for setting an arbitrary suction range in a direction parallel to the conveyance direction and for moving the suction range in a direction parallel to the conveyance direction in synchronization with the belt. In the above configuration, if the suction range is variable in the direction perpendicular to the conveyance direction, the suction range can be set in the direction perpendicular to the conveyance direction of sheet materials of different sizes, so suction holes that allow air to flow in and out There is nothing in the direction perpendicular to the direction. Also, if the suction range is set so as to block the maximum sheet gap in the direction parallel to the transport direction, it is possible to block the suction holes where the sheet material is not placed on the transport belt, and the suction range is parallel to the transport direction. If it can be moved to, all of the suction holes that allow air to flow in and out are blocked. As a result, all the suction force on the belt by the fan is collected under the sheet material, and the sheet material is completely attached to the belt.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) FIG. 1 is a drawing best showing the features of the present invention. In FIG. 1, 11 is a width regulating shutter.
As shown in FIG. 1B, when the large size sheet material 13 is conveyed, the width regulating shutter 11 is retracted so as not to block the opening of the duct 12. As a result, the large-size sheet material 13 obtains a suction force on the entire sheet material, and thus stable transportability is obtained.

As shown in FIG. 1A, when the small-sized sheet material 14 is conveyed, the width regulating shutter 11 blocks the opening of the duct 12 in accordance with the sheet material size. As a result, the suction hole 15 through which air easily escapes is closed by the shutter, and the small size sheet material 14 is also fixed on the belt with a strong suction force and stably conveyed. 16 is a fan.

(Second Embodiment) In FIG. 2, 21 is a width regulating shutter, 22 is a duct, 23 is a shutter, 24 is a shutter base, and 25 is a sensor. When the large size sheet material is conveyed, the width regulating shutter 21 is retracted from the opening of the duct 22. Further, the shutter 23 is located between the sheet materials being conveyed, and is set to a size equal to the maximum sheet material in a direction parallel to the conveying direction. For example, a plurality of shutters are mounted on an endless chain having the same speed as the conveyed sheets, Run while blocking the space between the sheet materials.

The shutter 23 is arranged on a shutter base 24, and a sensor 25 detects the leading edge of the sheet material. The shutter base 24 aligns the rear edge with the leading edge of the sheet material and moves the sheet material in the transport direction at a speed equal to the transport speed. It moves in the same direction while it is located in an empty place between the sheet materials. As a result, the large size sheet material receives a suction force only under the sheet material, so that a strong suction force can be obtained and stable transportability is generated.

When conveying a small size sheet, the width regulating shutter 21 slides in a direction perpendicular to the conveying direction of the sheet material, sets a suction range in the same range as the sheet material, and is a shutter arranged on the slide base 24. The sheet material 23 is set between the sheet materials of the sheet material whose leading end is detected after being set to the same size as the sheet material, and moves in the same direction as the sheet material conveying direction at the same speed as the sheet material.
As a result, even in the case of the small size sheet material, the suction range is only under the sheet material, and stable transportability due to a strong suction force can be obtained.

(Third Embodiment) 31 in FIG. 3 and FIG.
Is a slide valve, 32 is a duct, 33 is a suction hole, 34
Is a conveyor belt, and 35 is a sheet material. After detecting the sheet material size and the leading edge of the sheet material, the slide valve 31 is opened and closed according to the size and position of the conveyed sheet material. When the sheet material 35 passes over the slide valve 31 opened, a suction force is generated through the suction holes 33 of the conveyor belt 34, and the sheet material 35 is fixed on the conveyor belt 34. At this time, the open slide valve 31 is only the valve under the sheet material 35, that is, the plurality of valves 31 fixedly provided at the predetermined positions are closed at the positions between the sheets, and the spaces between the sheets are closed. If it passes, it allows the suction of the open sheet.

As a result, the suction force acts only under the sheet material, and the sheet material is fixed on the conveyor belt, so that stable conveying performance is exhibited.

(Fourth Embodiment) 41 in FIG. 5 and FIG.
Is a suction duct, 42 is a valve, 43 is a suction hole, 44 is a conveyor belt, and 45 is a sheet material. The valve is opened and closed according to the size and position of the sheet material to be conveyed after detecting the sheet material size and the leading edge of the sheet material. When the sheet material 45 passes through the suction duct 41 with the valve opened, a suction force is generated through the suction holes 43 on the belt 44, and the sheet material 45 is fixed on the conveyor belt 44. At this time, the only valve that is open is the valve that is connected to the suction duct under the seat material. As a result, the suction force works only under the sheet material, and the sheet material is fixed on the conveyor belt, so that stable conveying performance is exhibited.

[0015]

As described above, according to the present invention,
By changing the suction range according to the size of the sheet material, it is possible to effectively generate the suction force, especially when conveying small size sheet material. It will be advantageous to, and a cost advantage will be produced. Further, the improved transportability does not adversely affect the units located in the vicinity, and the reliability of the entire device is improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a first embodiment of the present invention, (a)
Shows a case of a small size sheet material, and (b) shows a case of a large size sheet material.

2A and 2B show a second embodiment of the present invention, in which FIG. 2A is a partially cutaway plan view showing the inside, and FIG. 2B is a sectional view.

FIG. 3 is a plan view of a third embodiment of the present invention.

4 is an enlarged view of a portion A in FIG. 3, (a) is a plan view, and (b) is a sectional view taken along line BB in (a).

FIG. 5 is a plan view of a fourth embodiment of the present invention.

6 is an enlarged view of a portion A in FIG. 5, (a) is a plan view, and (b) is a cross-sectional view of a main part in (a).

FIG. 7 shows a conventional example, (a) is a top view, and (b) is a cross-sectional view.

[Explanation of symbols]

11 ... Width regulation shutter 12 ... Duct 13 ... Large size sheet material 14 ... Small size sheet material 15 ... Suction hole 16 ... Fan 21 ... Width regulation shutter 22 ... Duct 23 ... Shutter 24 ... Shutter base 25 ... Sensor 31 ... Slide valve 32 ... Duct 33 ... Suction hole 34 ... Conveyor belt 35 ... Sheet material 41 ... Suction duct 42 ... Valve 43 ... Suction hole 44 ... Conveyor belt 45 ... Sheet material 51 ... Conveyor belt 52 ... Suction hole 53 ... Duct 54 ... Fan 55 ... Sheet Material

Claims (4)

[Claims] 1. A belt having a plurality of small holes as a conveying means, a support member for supporting the belt, a duct provided in the support member and having an opening surface at a lower portion of the belt, and a belt below the duct. In a belt conveying device having a fan on the opening surface opposite to the belt lower opening surface in order to generate suction force on the opening surface, a means for closing the belt lower duct opening in the range excluding the area on which the sheet material is placed is provided. A sheet material conveying device having. 2. The sheet material conveying apparatus according to claim 1, further comprising duct opening / closing means for changing and regulating the suction width over the entire conveying direction of the conveyor belt in the width direction with respect to the conveying direction. 3. The sheet material conveying apparatus according to claim 1, further comprising means for changing a suction range in a direction parallel to the conveying direction and for moving the suction range in synchronization with the belt. . 4. A duct opening / closing means for changing and regulating the suction width over the entire conveying direction of the conveyor belt in the width direction with respect to the conveying direction is provided, and the suction range is variable in a direction parallel to the conveying direction, and 2. The sheet material conveying device according to claim 1, further comprising means for moving the suction range in synchronization with the belt.