JPH1159929A - Sheet carrier device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To deliver a sheet toward a sheet carrier passage by correcting bias feeding of the sheet between a pickup roller and a carrier roller device at the time of delivering the sheet from a paper feeding tray. SOLUTION: A pickup roller 5 to be placed on a paper feeding part of a paper feeding tray 1 is constituted of a half moon roller, and a carrier roller device 10 is arranged on its downstream part. At the time of feeding paper, the carrier roller device 10 is stopped, the pickup roller 5 is rotated once, a head end part of a sheet P is made to intrude toward a nip part of the carrier roller device 10, and a loop Pr is formed on the sheet. Thereafter, work to return a rear end part by reaction force of the sheet is carried out at a position where a flat surface part 7 of the roller 5 is separated from the sheet, and thereafter, the sheet is delivered by driving the pickup roller and the carrier roller device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeder provided in a paper feeder of an image forming apparatus for feeding paper in a registered manner, and more particularly, to a paper feed path between a paper feed tray and an image transfer unit. The present invention relates to a paper transport device that is a small device that can feed paper in a state where skew of the paper is corrected when the paper is fed from a paper feed tray.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine or a printer, a pickup roller is disposed in a paper supply section of a paper storage member such as a paper supply tray, and the paper taken out by the pickup roller is transported by a transport roller device. And supplies it to the image recording unit. In the paper transport path in which the transport roller device is disposed, an aligning roller device and the like are disposed in order to automatically eliminate the skew state of the paper, and the paper is sent out from the paper feed tray in a skew state. In some cases, the skewed state is eliminated while being conveyed in the paper conveyance path.

It is also known that a registration roller device is arranged upstream of a toner image carrier such as a photosensitive drum in combination with a transport roller device of the paper transport path to perform a sheet aligning operation. In the sheet aligning device, a loop is formed on the sheet in a state where the leading end of the sheet enters the nip portion of the registration roller device, and the leading end of the sheet is moved to the axis of the registration roller device by the reaction force of the loop. Means are used to make the images coincide with each other, and then to send them to the image transfer unit. By using the above-described sheet aligning device, the skew of the sheet is eliminated at the position where the toner image formed on the photosensitive drum or the like is transferred to the sheet, and the recording is correctly formed at a predetermined position on the sheet. Can be done.

[0004]

However, in a device such as a printer or a copying machine which is configured as a small-sized image forming apparatus, a sheet conveying path from a sheet feeding tray to a photosensitive drum is very short. For this reason, there is a problem that the sheet aligning device cannot be arranged in the sheet transport path. In order to solve the skewing of a small device and paper as described above,
The problem can be easily solved if the skew of the paper does not occur with respect to the pickup roller that takes out the paper from the paper feed tray. However, even in a general small-sized image forming apparatus, various types of paper sizes are used, and the pickup roller cannot be arranged in correspondence with the center of the paper, and the pickup roller cannot be used for the paper. It is inevitable that skew occurs in the fed paper because the paper is at a position deviated from the center.

The present invention solves the above-mentioned problem of the paper feeding device of the conventional image forming apparatus, and adjusts the paper alignment between a pickup roller and a member such as a transport roller device disposed downstream thereof. An object of the present invention is to provide an apparatus capable of feeding paper to the next step by preventing skew of paper fed from a paper feed tray.

[0006]

According to a first aspect of the present invention, a sheet fed by a pickup roller provided in a sheet feeding section of a sheet feeding tray is provided at a downstream portion of the pickup roller. A paper leading end regulating member parallel to the axis of the pickup roller is provided. The invention according to claim 2 is characterized in that the sheet leading end member is a pair of transport roller devices. The invention according to claim 3 is characterized in that the pickup roller arranged on the paper feed tray is a half-moon roller.

With the configuration described above, in the paper transport apparatus of the present invention, the leading end of the paper sent from the paper feed tray is brought into contact with an object parallel to the axis of the pickup roller and fed by the pickup roller. By applying the function, the skew can be eliminated and the paper can be sent to the image recording unit. Further, as the sheet leading end portion regulating member, a stopped conveying roller device can be used, and skew correction can be performed in a state where the leading end of the sheet enters the nip portion of the conveying roller device. It is possible.
Further, it is also possible to eliminate the skew of the paper by performing a plurality of operations of intermittently pressing the leading end of the paper toward the nip portion of the transport roller device by using a half-moon roller as the pickup roller. .

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a sheet conveying device according to the present invention. The example shown in FIGS. 1 and 2 shows a mechanism for feeding the paper P from the paper feed tray 1 by the pickup roller 5, and the corner of the paper feed side tip of the paper P stored in the paper feed tray 1. A snubber 2 as a sheet separating member is disposed in the section. In the paper feed path from the paper feed tray, a transport roller device 10 is disposed at a predetermined interval from the pickup roller 5, and the transport roller device 10 is provided with a drive roller as in a general device. 11 and a pinch roller 12 are combined and arranged so as to have a predetermined nip pressure between the two rollers.

In this embodiment, a half-moon roller is used as the pick-up roller 5 disposed in the paper feed section from the paper feed tray 1.
Does not perform the feeding operation on the sheet at the position corresponding to the sheet. Further, the length of the circumferential surface 6 in contact with the paper can be set to an arbitrary length, and the length of the paper feeding can be appropriately adjusted during one rotation of the half-moon roller. It is configured as configurable.
The shaft 13 of the transport roller device 10 arranged in the paper transport path is arranged in parallel with the axis 8 of the pickup roller 5, and the paper P fed from the paper feed tray is moved along the reference line of the paper transport path. The sheet is conveyed and fed to an image recording unit (not shown).

[0010] Pickup roller 5 from the paper feed tray
As shown in FIG. 3, when the paper P is fed out, the feeding operation for the paper is performed by a length that the paper comes into contact with the circumferential portion 6 of the pickup roller 5. Then, as shown in FIGS. 3 and 4, the sheet fed from the sheet feed tray 1 is stopped in a state where the leading end of the sheet abuts on the nip portion 15 of the stopped transport roller device 10.
Then, the loop Pr is formed on the sheet by continuing the feeding action by the pickup roller. Thereafter, the half-moon roller rotates, and the notch 7 of the roller rotates.
Comes to a position corresponding to the sheet, the loop Pr of the sheet
An operation is performed in which the rear end of the sheet is returned to the sheet feed tray side due to the reaction force of. Simultaneously with the return operation of the sheet, a portion where the leading end of the sheet abuts on the nip portion 15 of the transport roller device and is stopped is parallel to the axis of the roller device, so that the skew of the sheet is corrected.

The occurrence of the skew of the sheet is, for example, as follows.
As shown as the sheet Pa in FIG. 4, the sheet sent by the pickup roller is not sent straight for some reason, but is sent to the conveying roller device in an oblique state. Then, the skewed sheet Pa enters the nip portion 15 of the transport roller device 10 with the leading end Pb inclined with respect to the axis of the transport roller device. Therefore, if the transport roller device 10 is driven in the same posture and sent toward the downstream portion, there is a disadvantage that the position of the image recorded on the sheet becomes oblique.

In order to solve the above-mentioned inconvenience,
In the present invention, the pickup roller 5 is caused to make one rotation to press the leading end portion Pb of the sheet to the nip position of the transport roller device 10, and a loop Pr is formed on the sheet as shown in FIG. The leading end Pb of the sheet is aligned with the nip position 15 of the transport roller device 10. Then, by driving the conveyance roller device, the paper is conveyed toward the image recording unit along the conveyance reference line 17 of the paper conveyance path.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the paper transporting apparatus constructed as described above, the operation of feeding and aligning (correcting skew) the paper from the paper feed tray can be performed as follows.

When the transport roller device 10 is stopped,
The pickup roller 5 is driven by one rotation to form a loop on the paper while pressing the leading end of the paper sent from the paper feed tray 1 against the nip 15 of the transport roller device 10.
When the pickup roller makes one rotation, the roller 5
The notch 7 corresponding to the paper is in a state corresponding to the paper, so that the action of advancing the paper is stopped, and the rear end of the paper is returned to the paper feed tray side by the reaction force of the loop. Rows are corrected. Next, 2
When the conveyance roller device 10 is driven at the same time as the first rotation, the sheet re-enters the nip portion of the conveyance roller device by the feeding action of the pickup roller, and the leading end of the sheet enters the nip portion 15 of the conveyance roller device 10. On the other hand, since the sheet enters in a state where the skew is eliminated, the sheet is conveyed by the conveying roller device 10 to the image recording section along the conveyance reference line 17 of the sheet conveying path.

When the transport roller device 10 is stopped,
The pickup roller 5 is driven by one rotation to form a loop on the paper while pressing the leading end of the paper sent from the paper feed tray 1 against the nip 15 of the transport roller device 10.
When the pickup roller makes one rotation, the roller 5
The notch 7 corresponds to the sheet, so that the action of advancing the sheet is stopped, and the rear end of the sheet is returned to the sheet feed tray by the reaction force of the loop. Thereafter, the skew of the sheet is corrected by repeating the operation of rotating the pickup roller one more time and causing the leading end of the sheet to coincide with the nip portion 15 of the transport roller device 10.

Next, 3
When the conveyance roller device 10 starts to be driven at the same time as the first rotation, the leading end of the sheet enters the nip portion 15 of the conveyance roller device 10 in a state where the skew is eliminated by the feeding action of the pickup roller. . Then, the skew-corrected sheet is transported by the transport roller device 10 to the image recording unit along the transport reference line 17 of the paper transport path.

As described above, in the apparatus for feeding the paper while correcting the skew of the paper, the pick-up roller is not limited to the half-moon roller, but has a normal cylindrical shape. A mechanism may be provided that uses a roller or the like to intermittently separate the roller from the sheet. And also when using the roller which separates from and touches the paper, when separating the roller from the paper,
If the action of returning the trailing end of the sheet to the paper feed tray side can be exerted, the same sheet aligning action as the half-moon roller can be exerted.
Further, as a sheet leading end regulating member provided downstream of the pickup roller, it is possible to arrange a gate member which can come and go in the sheet conveying path. Even in this case, the skew correction operation can be performed by regulating the leading edge of the sheet. After the skew correction, the gate is retracted, and then the pickup roller and the conveyance roller device are driven. Paper can be sent out.

[0018]

According to the apparatus of the present invention, the front end of the paper fed from the paper feed tray is brought into contact with an object parallel to the axis of the pickup roller and fed by the pickup roller. By applying the function, the skew can be eliminated and the paper can be sent to the image recording unit. Further, as the paper front end regulating member, a stopped conveyance roller device can be used, and skew correction can be performed in a state where the front end of the paper enters the nip portion of the conveyance roller device. It is. Furthermore, using a half-moon roller as the pickup roller,
It is also possible to eliminate the skew of the sheet by performing the operation of intermittently pressing the leading end of the sheet toward the nip portion of the transport roller device a plurality of times.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a configuration of a sheet conveying device of the present invention.

FIG. 2 is a plan view of the apparatus of FIG.

FIG. 3 is an explanatory diagram of an operation of feeding a sheet.

FIG. 4 is a plan view corresponding to FIG.

[Explanation of symbols]

1 paper feed tray, 2 snubber, 5 pickup roller, 6 arc surface, 7 notch, 8
Axis, 10 transport roller device, 11 drive roller member, 12 pinch roller member, 13 axis, 1
5 Nip, 17 reference lines.

Claims (3)

[Claims] 1. A sheet leading end regulating member parallel to an axis of the pickup roller is provided downstream of the pickup roller for a sheet fed by a pickup roller provided in a sheet feeding section of a sheet feeding tray. A sheet transport device characterized by the above-mentioned. 2. The sheet conveying device according to claim 1, wherein the sheet leading end member is a pair of conveying roller devices. 3. The sheet transporting device according to claim 1, wherein the pickup roller disposed on the sheet feeding tray is a half-moon roller.