JPH04260551A - Paper sheet feed device - Google Patents

Abstract

PURPOSE:To allow the leading end of a fed sheet to surely enter between nip parts of a pair of register rollers in a paper sheet feed device incorporated in an image forming device such as a printer or a copying machine. CONSTITUTION:An upper paper feed guide 3 is attached to a printer body 15 so as to be swingable about a support shaft 6 over a predetermined range, and accordingly, the guide 3 is rotated downward about the support shaft 16 by a pressure given by a loop 19 of a sheet S which abuts at its leading end 6 against the outer peripheral surface of the upper one of a pair of subscanning rollers 7 (register rollers), and accordingly, the leading end 6 of the sheet S is caught between the nip parts of the subscanning rollers 7.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet material feeding device installed in an image forming apparatus such as a printer or a copying machine. A pair of registration rollers disposed on the downstream side, and a sheet material conveyance guide interposed between the sheet feeding means and the pair of registration rollers to guide the leading edge of the fed sheet material into a nip portion of the pair of registration rollers. The present invention relates to a sheet material feeding device provided therein.

0002

2. Description of the Related Art FIG. 6 shows an inkjet type printer as an image forming apparatus equipped with the above-mentioned sheet material feeding device.

In this printer, when the half-moon-shaped pickup roller (paper feeding means) 1 rotates clockwise, the topmost paper of the sheet material S loaded in the paper feeding cassette 2 is separated one by one, as shown by the broken line. The paper is fed as follows.

[0004] The sheet material S fed by the pickup roller 1 is passed through upper and lower paper feeding guides (sheet material conveyance guides).
3 and 5, and its tip 6 is guided to the nip portion of a sub-scanning roller pair (registration roller pair) 7 whose rotation is stopped. When the leading end 6 comes into contact with the nip portion of the pair of sub-scanning rollers 7, the skew of the sheet material S is corrected.

Next, when the sub-scanning roller pair 7 is rotated in response to a print command signal, the sheet material S is sent onto the platen 9, where it is intermittently fed (sub-scanned) by the print width of the print head 10. At this time, the print head 10 moves along the rail 11 in the width direction of the sheet material S (main scanning) and sprays droplets onto the surface of the sheet material to perform printing.

When the leading edge 6 of the sheet material S enters the nip between the pair of paper ejection rollers 12 rotating synchronously with the pair of sub-scanning rollers 7, the sheet material S is conveyed to the pair of paper ejection rollers 12 and placed on the paper ejection tray 13. Paper is ejected on top.

Paper feed guide 3 of a conventional sheet material feeder,
5 is fixed to the printer body 15.

[0008]

By the way, in the above-mentioned printer, in order to correctly print by the print head 10, in addition to the main scanning of the print head 10, the sub-scanning roller pair 7, which is a pair of registration rollers, has to scan the sheet material S. Scanning also needs to be performed accurately with high feed precision.

[0009] For this reason, normally each roller of the sub-scanning roller pair 7 has a large coefficient of friction against the sheet material S. Generally, one roller (
The upper roller) is a rubber roller, and the other roller (lower roller) is a metal roller whose surface has been roughened by sandblasting.

However, when such a roller is used for each roller of the sub-scanning roller pair 7, the conventional printer main body 15
The leading edge 6 of the sheet material S guided by the paper feed guides 3 and 5 fixed to the sheet remains in contact with the outer peripheral surface of one of the sub-scanning roller pairs 7, and the nip of the sub-scanning roller pair 7 is maintained. You will not be accepted into the club. For this reason, it may not be possible to correctly correct the skew of the sheet material S, or
Corners of the sheet material S were sometimes bent. In particular, when the tip 6 of the sheet material S is curled, the angle at which it hits the outer peripheral surface of the roller becomes large, so it tends to remain in contact with the outer peripheral surface of the roller, and jams occur more frequently.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and provides a sheet material feeding device capable of correctly guiding the leading edge of a fed sheet material into a nip portion between a pair of registration rollers. The purpose is to

0012

[Means for Solving the Problems] For example, as shown in FIG. 1, the present invention provides a paper feeding means (
1), a pair of registration rollers (7) disposed on the downstream side of the paper feeding means (1), and a pair of registration rollers (7) interposed between the paper feeding means (1) and the pair of registration rollers (7) to feed the paper. sheet material (
The present invention relates to a sheet material feeding device including a sheet material conveying guide (3, 5) that guides the leading end (6) of the sheet material S) into the nip portion of a pair of registration rollers (7).

In order to achieve the above object, the present invention makes the sheet material conveyance guide (3) swingable in the vertical direction about the support shaft (16), and the registration roller pair (
7) The sheet material conveyance guide (3) swings around the support shaft (16) due to the pressure of the loop (19) formed in the sheet material (S) that hits the outer peripheral surface of the roller. It is characterized by:

[0014]

[Operation] According to the above configuration, the tip (6
), the sheet material conveyance guide (3) swings around the support shaft (16) due to the pressure of the loop (19) formed in the sheet material (S), thereby moving the nip portion of the pair of registration rollers (7). be led to.

[0015] The above reference numerals in parentheses are used to refer to the drawings and do not limit the structure in any way.

[0016]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings.

Embodiment 1 FIG. 1 shows the overall configuration of an inkjet type printer as an image forming apparatus equipped with a sheet material feeding device according to Embodiment 1 of the present invention.

In this printer, the same members as those in the conventional printer described above are given the same reference numerals, and descriptions of those that are functionally unchanged will be omitted.

In this printer, while the lower paper feed guide 5 is fixed to the printer body 15,
The upper paper feed guide 3 is attached to a support shaft 16 relative to the printer main body 15.
It is attached so that it can swing within a predetermined range in the vertical direction (in the direction of the arrow) around the center.

The paper feed guide 3 is supported on the paper feeding downstream side by a support shaft 16 that is the center of swing, and on the paper feeding upstream side is supported by a regulating shaft 17 that is a swing range regulating member. The support shaft 16, which is the center of swing, is fitted into a circular hole in the paper feed guide 3, and the regulation shaft 17, which is a swing range regulating member, is fitted into an oblong hole in the vertical direction.

Normally, the paper feed guide 3 is rotated about the support shaft 16 and lowered by its own weight to a position where the regulating shaft 17 abuts the upper end of the oblong hole (the state shown in the figure).

Now, when the sheet material S in the paper feed cassette 2 is fed by the pickup roller 1, the leading end 6 of the sheet material S is guided by the paper feed guides 3 and 5, and rotation is stopped. The image is conveyed toward the nip between the pair of sub-scanning rollers 7. In this case, the leading end 6 of the sheet material S is guided by the inclined lower paper feed guide 5 and heads toward the nip portion of the sub-scanning roller pair 7 located higher than the paper feed cassette 2 .

However, in many cases, the tip 6 of the sheet material S
Although it is guided by the lower paper feed guide 5, it does not enter the nip between the sub-scanning roller pair 7 and hits the outer peripheral surface of the upper roller, which is a rubber roller, as shown in FIG. 2(a). It ends up being left alone.

Therefore, the sheet material S is further continued to be fed by the pickup roller 1, and as shown in FIG. An upward loop 19 is formed between the two.

[0025] In this way, the upper paper feed guide 3 is rotated upward about the support shaft 16 by the pressure of the loop 19 until the regulating shaft 17 comes into contact with the lower end of the oblong hole. Due to this movement of the paper feed guide 3 (the downstream end of the paper feed moves downward), the leading edge 6 of the sheet material S that was in contact with the outer peripheral surface of the upper roller of the sub-scanning roller pair 7 is forcibly moved to the upper roller. The outer peripheral surface is moved and introduced into the nip portion of the sub-scanning roller pair 7.

Note that the leading edge 6 of the fed sheet material S does not remain in contact with the outer peripheral surface of the upper roller of the pair of sub-scanning rollers 7 as described above, but enters the nip of the pair of sub-scanning rollers 7. In this case, the tip 6 of the sheet material S has a loop 19
The movement of the upper paper feed guide 3, which moves upward due to the pressure, does not cause it to come out of the nip between the pair of sub-scanning rollers. This is because the pressing force by the loop 19 is acting on the tip 6 of the sheet material S.

Embodiment 2 FIG. 3 shows the overall configuration of an inkjet type printer as an image forming apparatus equipped with a sheet material feeding device according to Embodiment 2 of the present invention.

While the printer of the first embodiment uses a system in which the sheet material S is fed by the paper feed cassette 2, this printer adopts a system in which the sheet material S is manually fed.

A paper feed port 22 having a paper feed tray 21 is provided on the paper feed side 20 of the printer main body 15 . Further, a pair of paper feed rollers 23 is provided near the paper feed port 22 in the printer main body 15 .

The nip portion of the paper feed roller pair 23 is arranged at approximately the same height as the nip portion of the sub-scanning roller pair 7 (and the paper ejection roller pair 12), and the sheet material manually fed from the paper feed tray 21 is S is conveyed in a substantially horizontal state.

In such a printer, the state in which the leading edge 6 of the sheet material S fed by the pair of paper feed rollers 23 abuts against the pair of sub-scanning rollers 7 is not uniform. If there is no curl at the tip 6 of the sheet material S,
Normally, the tip 6 is introduced into the nip between the pair of sub-scanning rollers 7, but even in this case, the tip 6 may remain in contact with the outer peripheral surface of the upper roller, which is a rubber roller, or the surface may be sandblasted. It may remain in contact with the outer peripheral surface of the lower roller, which is a metal roller. When the leading edge 6 of the sheet material S is curled upward, it often remains in contact with the outer circumferential surface of the upper roller, and when the leading edge 6 of the sheet material S is curled downward, It often remains in contact with the outer peripheral surface of the lower roller.

In this embodiment, even if the leading edge 6 of the fed sheet material S is curled upward or downward, it can be reliably introduced into the nip portion of the pair of sub-scanning rollers 7. This is what I did.

In this printer, the upper paper feed guide 3
The lower paper feed guide 5 is attached to the printer main body 15 so as to be able to swing within a predetermined range in the vertical direction (in the direction of the arrow) about a support shaft 16 .

The paper feed guides 3 and 5 are supported on the paper feeding downstream side by a support shaft 16 that is the center of swing, and on the paper feeding upstream side are supported by a regulating shaft 17 that is a swing range regulating member. The support shaft 16, which is the center of the swing, is fitted into a circular hole in the paper feed guides 3, 5, and the regulation shaft 17, which is a swing range regulating member, is fitted into an oblong hole in the vertical direction.

The upper paper feed guide 3 normally rotates down by its own weight around the support shaft 16 to a position where the regulation shaft 17 abuts the upper end of the oblong hole. On the other hand, the lower paper feed guide 5 is normally pushed up by the coil spring 25 and rotated upward about the support shaft 16 to a position where the regulating shaft 17 contacts the lower end of the oblong hole (as shown in the figure). situation).

The coil spring 25 has a minimum spring force capable of holding the paper feed guide 5 at a position where the regulating shaft 17 contacts the lower end of the oblong hole. Therefore, when a slight pressing force is applied to the upper surface side of the paper feed guide 5,
The paper feed guide 5 has a coil spring 25 centered around the support shaft 16.
It rotates and descends against the

The upper paper feed guide 3 is bent in an inverted V-shape on the downstream side of the paper feed, and bent in a V-shape on the upstream side of the paper feed. Further, the lower paper feed guide 5 has a horizontal shape on the paper feeding downstream side and a V-shaped bent shape on the paper feeding upstream side.

Now, when the sheet material S manually fed from the paper feed tray 21 is fed by the paper feed roller pair 23, the leading edge 6 of the sheet material S is guided by the paper feed guides 3 and 5, and the sheet material S is rotated. The paper is conveyed toward the nip between the stopped sub-scanning roller pair 7. In this case, the leading end 6 of the sheet material S is conveyed in a substantially horizontal state between the paper feed guides 3 and 5 toward the nip portion of the pair of sub-scanning rollers 7.

However, if the leading edge 6 of the fed sheet material S is curled downward, it will not enter the nip between the pair of sub-scanning rollers 7, as shown in the figure, and the lower roller of the pair of sub-scanning rollers 7 will It remains in contact with the outer circumferential surface of the

Therefore, the sheet material S is continued to be fed by the paper feed roller pair 23, and first, as shown in FIG. An upward loop 26 is formed between the V-shaped bent portion and the horizontal portion of the lower sheet feeding guide 5 on the paper feeding downstream side.

[0041] In this way, the upper paper feed guide 3 is rotated upward about the support shaft 16 by the pressure of the loop 26 to the position where the regulation shaft 17 abuts the lower end of the oval hole.

Next, the sheet material S is pushed down so that a downward direction is formed between the V-shaped bent part on the upstream side of the paper feed of the upper paper feed guide 3 and the V-shaped bent part on the upstream side of the paper feed on the lower side. A loop 27 is formed.

[0043] In this way, the pressure of the loop 27 causes the lower paper feed guide 5 to rotate downward about the support shaft 16 until the regulating shaft 17 comes into contact with the upper end of the oblong hole. Due to this movement of the paper feed guide 5 (the downstream end of the paper feed moves upward), the leading edge 6 of the sheet material S that was in contact with the outer peripheral surface of the lower roller of the sub-scanning roller pair 7 is forced downward. The outer peripheral surface of the roller is moved and introduced into the nip portion of the sub-scanning roller pair 7.

Here, the leading edge 6 of the fed sheet material S is
The leading edge of the fed sheet material S is curled upward, and this hits the lower roller of the sub-scanning roller pair 7. When the sheet material S hits the upper roller, the upper paper feed guide 3 is moved upward by the pressure of the loop 26, and the leading edge 6 of the sheet material S is introduced into the nip portion of the sub-scanning roller pair 7.

Furthermore, when the leading edge 6 of the fed sheet material S enters the nip between the pair of sub-scanning rollers 7, even if the upper paper feeding guide 3 moves upward due to the loop 26, it will not move due to the loop 27. Even if the lower paper feed guide 5 moves downward, the leading end 6 does not come out of the nip between the pair of sub-scanning rollers 7.

Note that the sub-scanning roller pair 7 in the first and second embodiments stops rotating when the sheet material S is fed, but when the sheet material S is fed, the sub-scanning roller pair 7 A similar function can also be achieved by a device that corrects skew by rotating in the opposite direction.

In addition, in a printer in which the sheet material S is manually fed from the paper output tray 13 side, the fed sheet material S is once sent between the paper feed guides 3 and 5 by the sub-scanning roller pair 7. However, in this case, if the paper feed guides 3 and 5 are normally placed apart from the nip portion of the sub-scanning roller pair 7, the leading edge of the fed sheet material S will be at the end of the paper feed guides 3 and 5. It will not get caught and cause a conveyance failure.

[0048]

As explained above, the sheet material feeding device of the present invention enables the sheet material conveyance guide to swing vertically around the spindle, and the sheet material feeding device of the present invention enables the sheet material conveyance guide to swing vertically around the support shaft, and to Since the sheet material conveyance guide is made to swing around the spindle due to the pressure of the loop formed in the material, it is possible to correctly guide the leading end of the fed sheet material into the nip portion of the pair of registration rollers. There are advantages that can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional side view showing the overall configuration of an image forming apparatus (inkjet printer) equipped with a sheet material feeding device according to a first embodiment of the present invention.

FIG. 2 is a longitudinal cross-sectional side view of main parts showing the operating state of the sheet material feeding device according to the first embodiment.

FIG. 3 is a longitudinal sectional side view showing the overall configuration of an image forming apparatus (inkjet printer) equipped with a sheet material feeding device according to a second embodiment of the present invention.

FIG. 4 is a longitudinal side view showing the operating state of the sheet material feeding device according to the second embodiment.

FIG. 5 is a longitudinal side view showing the operating state of the sheet material feeding device according to the second embodiment.

FIG. 6 is a longitudinal side view showing the overall configuration of a conventional image forming apparatus (inkjet printer).

[Explanation of symbols]

1 Pickup roller (paper feeding means) 3, 5 Paper feeding guide (sheet material conveyance guide) 6 Leading edge of sheet material 7
Sub-scanning roller pair (registration roller pair) 16
Support shafts 19, 26, 27 of paper feed guide
Loop 23 Paper feeding roller pair (paper feeding means) S Sheet material

Claims (1)

[Claims] 1. A sheet feeding means for feeding a sheet material, a pair of registration rollers disposed downstream of the sheet feeding means, and a pair of registration rollers interposed between the sheet feeding means and the pair of registration rollers for feeding the sheet material. A sheet material feeding device comprising a sheet material conveyance guide that guides a leading end of a sheet material into a nip portion of a pair of registration rollers, wherein the sheet material conveyance guide is swingable in the vertical direction about a spindle, A sheet material feeding device characterized in that the sheet material conveyance guide swings about the support shaft by the pressure of a loop formed in the sheet material that abuts the outer peripheral surface of the roller of the pair of registration rollers.