JPH08310704A - Paper transferring device - Google Patents

Abstract

PURPOSE: To prevent paper from becoming wrinkled when the paper is transferred by providing nearly equal transferring force on the center and both ends of the paper. CONSTITUTION: This device has a straight driving roller 17 having a length corresponding to the width of paper, a roller shaft 23 which is biased to the driving roller 17 side near both ends thereof and disposed in parallel to the driving roller 17 and a plurality of straight divided rollers 24 to 26 which are divided into a specified length according to the change of the radius of curvature when the roller shaft 23 is deflected and have smaller diameters toward the both ends of the roller shaft 23 from the center thereof and rotatably fitted on the roller shafts 23 without any open spacing. All divided roller 24 to 26 are abutted on the driving roller 17 with nearly equal force and rotated with the same circumferencial speed as that of the driving roller 17.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper sheet conveying apparatus for conveying paper sheets by a pair of rollers in an office machine.

[0002]

2. Description of the Related Art As shown in FIG. 3, a motor (not shown)
A driven roller 100 and a driven roller 101 driven by the roller are rotatably provided, and both ends of a roller shaft 102 of the driven roller 101 are urged toward the driving roller 100 by springs 103 so that the driving roller 100 and the driven roller 101 are separated from each other. There is a sheet conveying device that conveys a sheet.

Further, instead of the driven roller 101 of FIG. 3,
As shown in FIG. 5, a driven roller 105 in which a plurality of rollers 104 are arranged on a roller shaft 102 at a predetermined interval is used, and a portion corresponding to both ends of the roller shaft 102 and adjacent rollers 104 is attached by a spring 103. There is a sheet conveying device that is urged.

Further, in place of the driven roller 101 of FIG. 3, as shown in FIG. 6, a straight roller 106,
The roller shaft 102 includes two rollers 107 having a taper whose outer diameter becomes gradually smaller as the rollers 106 are separated from each other.
There is a paper sheet conveying device in which driven rollers 108 arranged in the above are used and both ends of the roller shaft 102 are biased by springs 103.

[0005]

In the driven roller 101 shown in FIG. 3, since the roller shaft 102 is biased at a portion which exceeds the effective range L of the driven roller 101 by a length of La, the roller shaft 102 is urged. A rotational moment acting on the outer periphery of the end surface 101a of the driven roller 101, which contacts the outer periphery of the drive roller 100, has La as the arm length, and acts on 102. That is, the roller shaft 102 bends in a curved shape, and only the both ends of the driven roller 101 are brought into pressure contact with the drive roller 100, but the center part thereof separates from the drive roller 100. As a result, the carrying force acts only on both sides of the paper sheet.

In this case, when the pickup roller 109 is provided on the upstream side as shown in FIG. 4, the pickup roller 109 is usually the downstream conveying roller (in this case, the driving roller 100 and the driven roller 101). After the paper sheet S is delivered to the
The central portion is braked by the pickup roller 109 and both sides are pulled by the rollers 100 and 101.
As a result, wrinkles 110 are formed which are inclined from both sides of the leading edge of the paper sheet S toward the center rear. This wrinkle 110 is pressed into an uncorrectable state when there is a fixing roller 111 that fixes the transferred image on the paper sheet S on the downstream side.

In the driven roller 105 shown in FIG. 5, since both ends and the intermediate portion of the roller shaft 102 are biased, the roller shaft 102 does not bend, and each roller 104 is pressed against the driving roller 100 over the entire length. To be done. However, the paper sheet S falls into the space formed between the rollers 104, and a streak is formed on the paper sheet S due to the pressure of the edge 104a of each roller 104.

In the driven roller 108 shown in FIG. 6, since the rollers 107 arranged on both sides have a taper, the outer circumferences of the rollers 106 and 107 are pressed against the driving roller 100 over the entire length even if the roller shaft 102 is curved. It is possible. However, when the roller 107 having a taper is rotated following by the friction with the driving roller 100, the peripheral speeds v1 and v2 at the both ends are different, so that the sheet S is given uneven resistance.

An example of using a resist roller on the driven side of a roller having a taper that narrows toward both sides is described in Japanese Utility Model Publication No. 6-38825, which is similar to that shown in FIG. Is expected to occur. When a roller having such a taper is used on the drive side of the registration roller, a difference occurs in the receiving force between the center and both sides of the sheet. Also, fairness 6-3
Japanese Patent No. 8825 discloses an example in which a large-diameter roller is arranged at the center of the shaft and a small-diameter roller is arranged at the end of the shaft. In this example, it is expected that the nip amount between the pair of rollers will be equal even if the shaft is curved, but since the rollers are arranged with a predetermined gap, the rollers are separated from the edge of each roller. The pressure may cause streaks on the paper sheet.

[0010]

According to the present invention, a drive roller having a length corresponding to the width of a sheet and having a straight shape and driven by a motor is provided, and both ends are attached to the drive roller side. A roller shaft that is energized and extends in parallel with the drive roller is provided, and the roller shaft is divided into a predetermined length according to the change in the radius of curvature when the roller shaft bends, and the arrangement position on the roller shaft is A paper feed provided with a plurality of straight-shaped dividing rollers each having a smaller outer diameter from the center of the roller shaft toward the both ends and rotatably fitted to the roller shaft without any space therebetween. It is a device.

[0011]

A plurality of divided rollers divided into predetermined lengths are arranged on the roller shaft according to the change of the radius of curvature of the roller shaft during the bending operation, and the arrangement position on the roller shaft is the center of the roller shaft. Since the outer diameter of the split roller is set to a small value from the portion toward both ends, even if the roller shaft is curved, all of the split rollers come into contact with the drive roller. Further, since the shape of the divided rollers is straight, the individual divided rollers follow and rotate at the peripheral speed equal to the peripheral speed of the drive roller regardless of the difference in the axial position even if the outer diameters are different.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. First, the structure and operation of the printer P in which the paper sheet transporting device of the present invention is used will be described with reference to FIG. The printer P is an example of a laser printer that prints by electrophotography. That is, 1 is a housing. A photoconductor 2 is rotatably provided in the center of the housing 1. Around the periphery of the photoconductor 2, a charger 3 for charging the outer periphery of the photoconductor 2, an exposure unit 5 for scanning the photoconductor 2 with a laser beam 4 corresponding to image data to form an electrostatic latent image, and a photoconductor. A developing device 6 that develops the electrostatic latent image on the body 2, a transfer charger 8 that transfers the developed image on the photoconductor 2 onto a sheet 7 that is a sheet, and a cleaning blade 9 that wipes off the toner remaining on the photoconductor 2. A cleaning unit 10 having the above and a charge eliminating lamp 11 for eliminating the charge of the photoconductor 2 are arranged.

A paper feed cassette 12 is provided on one side of the housing 1.
Is detachably installed. In this paper feed cassette 12, a pressing plate 13 that supports a large number of paper sheets 7 is provided with a spring 1.
It is urged upward by 4 and is provided so that it can be raised and lowered.
Further, a rotatable pickup roller 15 for pulling out the uppermost sheet 7 in the sheet feeding cassette 12, a friction pad 16 which is elastically contacted with the pickup roller 15 to prevent double feeding of the sheet 7, and a pickup roller 15 A drive roller 17 that conveys the sheet 7 pulled out by the drive roller 17 in synchronization with the rotational movement of the photoconductor 2, a driven roller 18 that elastically contacts the drive roller 17, and a photoconductor 2
A heating roller 19 for applying heat to the sheet 7 that has passed through
A pressure roller 20 for pressing the paper 7 against the heating roller 19
Are provided.

In such a printer P, in the process of rotating the photoconductor 2, the outer periphery of the photoconductor 2 is charged by the charging charger 3, and an electrostatic latent image is formed on the charged portion by the exposure unit 5. This electrostatic latent image is developed by the developing device 6. On the other hand, the paper 7 in the paper feeding cassette 12 is pulled out by the pickup roller 15 and stands by in a state in which the leading end abuts on the nip portion between the driving roller 17 and the driven roller 18, and is driven in accordance with the rotational movement of the photoconductor 2. When the roller 17 is driven, the paper 7 is supplied to the photoconductor 2 by the drive roller 17 and the driven roller 18, and the developed image on the photoconductor 2 is transferred by the transfer charger 8. The transferred image is fixed on the paper 7 after the transfer by the heating roller 19 and the pressure roller 20.

Next, the structure of the driving roller 17 and the driven roller 18 will be described in detail with reference to FIG. Drive roller 1
Reference numeral 7 includes a drive shaft 21 and a straight roller 22 fixedly fitted to the drive shaft 21. Drive shaft 21
Are rotatably supported by frames (not shown) arranged opposite to each other inside the casing 1, and one end thereof is connected to a motor (not shown). The length L of the roller 22 of the drive roller 17 is set to a value with which the letter-size or legal-size paper 7 can be conveyed.

The driven roller 18 is composed of a roller shaft 23 parallel to the drive roller 17 and a plurality of divided rollers 24, 25 and 26 rotatably fitted to the roller shaft 23.
All of these split rollers 24, 25, 26 are defined in a straight shape in which the outer diameter does not change depending on the position in the axial direction. Is set to be substantially equal to the length L of. The divided rollers 24, 25, and 26 are arranged such that the arrangement position on the roller shaft 23 is set to have a smaller outer diameter from the central portion of the roller shaft 23 toward both ends. Specifically, the split rollers 24 arranged in the center have an outer diameter d3 of 10.4 mm and a length L3.
Is 30 mm, and two split rollers 2 arranged on both sides
5, the outer diameter d2 is 10.3 mm, the length L2 is 31 mm,
The two split rollers 26 arranged on both sides have an outer diameter d
1 is set to 10 mm and the length L1 is set to 65.1 mm, but these values are examples and are not limited to these values. Further, the roller shaft 23 is a split roller 26.
Both ends of the outer side of the drive roller 17 are urged toward the drive roller 17 by springs 28 held by a base 27. The base 27 is provided inside the housing 1.

In such a structure, the image formation has already been described and the description thereof will be omitted. Here, the sheet feeding operation between the driving roller 17 and the driven roller 18 will be described. Since both ends of the roller shaft 23 are urged toward the drive roller 17 by springs 28, the roller shaft 23 is curved so that the drive roller 17 approaches both ends and the central part moves away from the drive roller 17.

However, the lengths of the split rollers 24, 25, 26 are set to a predetermined length in accordance with the change of the radius of curvature during the bending operation of the roller shaft 23, and the split rollers 24, 25, 26 are arranged on the roller shaft 23. Since the position is set to have a smaller outer diameter from the central portion of the roller shaft 23 toward both ends, all of the divided rollers 24, 25, and 26 can be brought into contact with the roller 22 of the drive roller 17. Therefore, even with the paper 7 having the maximum width, all the split rollers 24, 2
5, 26 are pressed against the roller 22 of the driving roller 17 with a substantially uniform force. Therefore, the split rollers 24, 25,
Although 26 have different outer diameters, the rollers 26 independently follow and rotate at a peripheral speed equal to the peripheral speed of the drive roller 17 due to friction with the sheet 7 conveyed by the drive roller 17.
Further, as shown in FIG. 1, the split roller 2 having a particularly long overall length is used.
As in the case of No. 6, even if the outer end side comes into contact with the drive roller 17, the inner end side may not come into contact with the drive roller 17; Even if the drive roller 17 is separated from the drive roller 17, a part of the drive roller 17 comes into contact with the drive roller 17, so that the follow roller can be rotated at a constant peripheral speed over the entire length. Therefore, the central part of the paper 7,
It is possible to prevent the wrinkles from being generated on the sheet 7 by applying a substantially equal conveying force to both side portions. In addition, the split rollers 24,
Since the sheets 25 and 26 are arranged without a gap, the sheet 7 does not fall between the dividing rollers 24, 25 and 26.
It is also possible to avoid making a streak on the sheet 7 at the edge of the edge of the sheet 6.

In the above-mentioned embodiment, the driving roller 17 and the driven roller 18 function as registration rollers, but the driving roller of the present invention, and the driven roller composed of the roller shaft and the split roller, are provided at other locations. The sheet may be conveyed. Further, the paper sheet conveying apparatus of the present invention is also applied to the case of conveying a sheet in an image forming apparatus such as a printer, a copying machine, or a facsimile of another type, or the case of conveying a document in an image reading apparatus. Is.

[0020]

According to the present invention, a plurality of divided rollers divided into predetermined lengths are arranged on the roller shaft in accordance with the change in the radius of curvature during the bending operation of the roller shaft, and the arrangement position on the roller shaft. Since the outer diameter of the split roller is set to a small value from the center of the roller shaft toward both ends, even if the roller shaft is curved, each of the split rollers can be brought into contact with the drive roller. . Further, since the shape of the divided rollers is straight, the individual divided rollers follow and rotate at the peripheral speed equal to the peripheral speed of the drive roller regardless of the difference in the axial position even if the outer diameters are different. Therefore, it is possible to apply a substantially equal conveying force to the central portion and both side portions of the paper sheet and prevent the paper sheet from wrinkling. Also,
Since the dividing rollers are arranged without gaps, the sheets do not fall between the dividing rollers, and therefore, it is also possible to prevent the edges of the dividing rollers from streaking the sheets. You can

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention and is a front view of a paper sheet transporting device, a part of which is a cross section.

FIG. 2 shows an example of mounting the paper sheet transporting device of the present invention,
FIG. 3 is a vertical sectional side view showing the internal structure of the printer.

FIG. 3 shows a first conventional example and is a front view of a paper sheet transporting device, a part of which is a cross section.

FIG. 4 is a plan view showing the paper sheet conveying operation.

FIG. 5 shows a second conventional example and is a front view of a paper sheet transporting device, a part of which is a cross section.

FIG. 6 shows a third conventional example, and is a front view of a paper sheet transporting device with a part in cross section.

[Explanation of symbols]

 17 Drive roller 23 Roller shaft 24 to 26 Split roller

Claims (1)

[Claims] 1. A drive roller which has a length corresponding to the width of a paper sheet and which is defined in a straight shape and driven by a motor; and both ends of the drive roller are biased toward the drive roller side and installed in parallel with the drive roller. The roller shaft is divided into a predetermined length in accordance with the change in the radius of curvature of the roller shaft during the bending operation, and the arrangement position on the roller shaft becomes smaller from the central portion of the roller shaft toward both ends. A plurality of straight-shaped split rollers each having an outer diameter and rotatably fitted to the roller shaft without any space therebetween, and a sheet transporting device.