JPH0355555Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a paper feeding device for feeding sheets, such as a sheet tray of a copying machine.

Sheet feeding in which multiple types of sheets of different sizes are arranged at a fixed position with one side edge of the sheets aligned with a type of paper feeding device such as a copying machine or a printer. There is an edge-based paper feeding device that selectively feeds paper using rollers.

In this paper feeding device, the sheet feeding roller feeds sheets of different sizes. The configuration is such that it is not possible to align the centers in the width direction of all the sheets being fed.

In this sheet feeding device, the sheet conveying roller for conveying the sheet fed by the sheet feeding roller to the downstream side of the sheet path normally contacts the center of the sheet conveyance, that is, the sheet of the sheet conveying roller. The center in the width direction of the circumferential surface of the roller is configured to substantially coincide with the center in the width direction of the largest size sheet conveyed by the sheet conveyance roller.

Therefore, in conventional paper feeding devices, the sheet feeding center of the sheet feeding roller occupies a position offset from the sheet feeding center of the sheet feeding roller, which has the disadvantage that the sheets being fed may skew. .

Purpose An object of the present invention is to provide a paper feeding device that can feed sheets fed by a sheet feeding roller without skewing the sheets.

Configuration The present invention includes a sheet feeding roller for feeding multiple types of sheets of different sizes with one side edge aligned, and a sheet feeding roller that feeds the sheets with one side edge aligned. In a paper feeding device including a sheet conveyance roller for conveying a sheet to a downstream of a sheet path, the sheet conveyance roller is configured to
a sheet conveying effective section having a length substantially the same as the width of the largest size sheet used in the paper feeding device and substantially the same length as the width of the smallest size sheet used; The position corresponding to the widthwise center of the minimum size sheet coincides with the lengthwise center of the sheet feeding roller, and the sheet conveyance effective part It is characterized in that the center in the longitudinal direction of the sheet feeding roller substantially coincides with the center in the longitudinal direction of the sheet feeding roller.

Next, a specific example of the configuration of the present invention will be explained in detail based on the drawings.

In FIG. 1, the first sheet tray 1 has A
A sheet of size S _A is loaded. Also the second
B-sized sheets S _B are stacked on the sheet tray 2 of .

The sheet S _A is fed by the first sheet feeding roller 10 rotating in the direction of arrow a.
After the fed sheets S _A are prevented from being fed in multiple sheets by the feed roller 11 and the reverse roller 12, they are sequentially conveyed through _the first sheet path 13 one by one.

On the other hand, the sheet S _B is transferred to the second sheet feeding roller 2.
After the sheet S B is fed by rotating in the direction of the arrow a, and the feeding of multiple sheets S _B is prevented by the feed roller 21 and the reverse roller 22,
The sheets are sequentially conveyed through the second sheet path 23 one by one.

Here, the first sheet tray 1 and the second sheet tray 2 are arranged to be able to be raised and lowered by a tray lifting device (not shown), and the sheets S _A and S _B stacked thereon are The sheet feeding roller 10 and the second sheet feeding roller 20 are raised and lowered so that they are always in contact with the peripheral surfaces of the sheet feeding roller 10 and the second sheet feeding roller 20 with appropriate pressure.

The first sheet path 13 and the second sheet path 23 are formed by first sheet guides 13a, 13b and second sheet guides 23a, 23b, respectively, and have respective sheet delivery sections 13c, 23c. are formed so that they merge with each other. A pair of rollers 30a and 3 are provided downstream of the sheet path of the sheet delivery sections 13c and 23c.
A sheet conveyance roller 30 made of 0b is provided. A paper sensor (not shown) is disposed on the sheet path formed by the pair of rollers 30a, 30b. This paper sensor detects that the leading edge of the sheet S _A or the sheet S _B is sent to the sheet conveying roller 30 and stops the rotation of the feed rollers 11 and 21 .

Note that each of the sheet feeding rollers 10 and 20 rotates for a time necessary to feed the sheet S _A or the sheet S _B to the feed roller 11 or the feed roller 21, and then is stopped.

The sheet conveying roller 30 conveys the sheet S _A or the sheet S _B through a third sheet path 31 formed by the third sheet guides 31 a and 31 b, and the leading edge of the sheet S _A or the sheet S _B is The drive is cut off when the registration roller 32 pinches the registration roller 32. The registration rollers 32 start rotating at a predetermined timing and convey the sheet S _A or the sheet S _B to the transfer section 34 around the photoreceptor 33 of the copying machine.

By the way, the first sheet tray 1 and the second sheet tray 2 contain sheets S _A and S _B.
In addition, sheets of various sizes are exchanged and stacked at appropriate times. For this reason, the sheet feeding rollers 10, 20
The sheet feeding center O of the feed rollers 11, 21, etc. usually coincides with the widthwise center O _A of the smallest size sheet, for example, an A size sheet S _A as shown in FIG. For example, it does not coincide with the center O _B of sheet S _B. On the other hand, the sheet conveyance center O _O of a conventional sheet conveyance roller is usually used for the largest size sheet, for example, B
It is configured to approximately coincide with the widthwise center O _B of the sheet S _B of size. Therefore, the sheet
S _A or sheet S _B etc. is the sheet conveying roller 30
When the sheet is further conveyed with the rotation of the sheet feeding roller 10 or 20 and the feed roller 11 or 21 stopped, the sheet larger than the sheet S _A is fed to the sheet feeding roller 10, 20, feed rollers 11, 21 and reverse rollers 12, 2
2 acts as a load in a direction that prevents the conveyance of the sheet, so that the sheets skew to the left in FIG. As described above, the cause of skew occurring in large sheets is the sheet conveyance center O _O of the sheet conveyance roller 30, the sheet conveyance rollers 10, 20, feed rollers 11, 21, and reverse rollers 12, 22. The deviation from the sheet feeding center O generates a force that moves the sheet in the width direction.

Therefore, for example, as shown in FIG. 2, at least one of the sheet conveying rollers 30
Sheet conveyance center of b (roller 30a may be used)
In order to match O _O ' with the sheet feeding center O, the length l of the roller portion of the roller 30b that contributes to sheet conveyance (hereinafter referred to as an effective portion) is set to be the same on the left and right with respect to the sheet feeding center O. The diameter of the ineffective portion of the roller 30b other than the above-mentioned effective portion is made small so that the sheet conveying function thereof is cut off. Here, although the above-mentioned ineffective portion of the roller 30b does not have to be formed in the shape of a roller, by forming the ineffective portion in the shape of a roller, it is possible to prevent a large sheet from sagging.

As is clear here, in the above-described paper feeding device, the sheet conveying center O _O ' of the sheet conveying roller 30 is located at the center of the sheet conveying roller 10, 20 and the feed roller 1.
Since the sheet is conveyed while always aligned with the sheet feeding center O such as 1, 21, etc., the load caused by the stoppage of the sheet feeding rollers 10, 20, etc. is always applied to the center of the effective portion of the sheet conveying roller 30. do. Therefore, in this paper feeding device, no force is generated to move the sheet in the width direction due to the above-mentioned load.

Effects According to the present invention, sheets can be fed without skewing.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view of the paper feeding device of the present invention, and FIG. 2 is a schematic plan view of the paper feeding device. S _A , S _B ... Sheet, 10, 20 ... Sheet feeding roller, 30 ... Sheet transport roller.

Claims (1)

[Scope of Claim for Utility Model Registration] A sheet feeding roller for feeding multiple types of sheets of different sizes with one side edge aligned; In a paper feeding device equipped with a sheet transport roller for transporting the fed sheet downstream of a sheet path, the sheet transport roller has a length that is approximately the same as the width of the largest size sheet used in the paper feeding device. It consists of an effective sheet conveyance section that has a width and a length that is approximately the same as the width of the minimum size sheet to be used, and an ineffective sheet conveyance section that has a smaller diameter than this effective sheet conveyance section, and A position corresponding to the center in the width direction of the sheet and the center in the length direction of the sheet feeding roller are aligned, and a center in the length direction of the effective sheet conveyance section and a center in the length direction of the sheet feeding roller are aligned. A paper feeding device characterized in that the two substantially coincide with each other.