JPH09235047A - Skew correction device of cut sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To certainly correct a skew produced at the time of paper feeding making an interval not producing a sag on a cut sheet and facilitating conversion of force of the cut sheet to produce the sag to torque around a vertical shaft in the flat surface direction of the sheet as its center. SOLUTION: It is constituted to provide a paper guide pair 7 between a carrier roller pair 4 and a registration roller 6, and a skew correction device of a cut sheet 2 devised to convert force of the cut sheet 2 to produce a sag to torque around a shaft vertical in the flat surface direction of the cut sheet 2 as its center by making a clearance interval of the paper guide pair 7 slightly wider than thickness of the maximum cut sheet to carry and making it the interval not to produce the sag on the cut sheet 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a skew correction device for cut sheets used in inkjet printers, laser printers, facsimiles, copiers and the like.

[0002]

2. Description of the Related Art In recent years, printers, facsimiles, copying machines and the like are required to have high printing speed. In particular, as the printing speed is improved, high reliability is being demanded for the surface of paper conveyance, and higher reliability is particularly required for skew (skew) and jamming.

A skew correction device in a conventional cut sheet conveying device will be described below. FIG. 6 is a cross-sectional view showing a conventional skew correction device using a registration roller driven intermittently. FIG. 7 is a plan view showing a second conventional skew correction device using a skew roller.

In FIG. 6, 1 is a sheet storage member that accommodates a large number of sheets and is detachably attached to the apparatus main body, and 2 is a cut sheet that is attached to the sheet storage member 1 by a predetermined amount. The cut sheet 2 is a feeding means (pickup roller) 3
Then, the cut sheet 2 is taken out from the sheet storage member 1 and guided to a pair of conveyance rollers 4 for separating and conveying the cut sheet 2. A pressure member 5 applies pressure between the pair of conveying rollers 4, and the cut sheet 2 is conveyed in the same direction as the pair of conveying rollers 4 at a predetermined timing downstream of the conveyed cut sheet 2 in the traveling direction. A pair of paper guides 7 are provided to guide the rotating registration rollers 6. The paper guide pair 7 is configured to greatly widen the gap distance at a position away from the registration roller 6.

The operation of the skew correcting apparatus in the conventional cut sheet conveying apparatus configured as described above will be described below.

When a paper feed signal for rotating the pickup roller 3 is output, the pickup roller 3 rotates and picks up the uppermost portion of the cut sheet 2 set in the sheet storage member 1 and sends it to the pair of conveying rollers 4. . The cut sheet 2 sent out is conveyed downstream by the conveying roller pair 4 along the paper guide pair 7, and one of the tip angles reaches a nip of the registration roller 6 which has not received a rotation instruction and is fed. In order to correct the skew of the cut sheet 2 that has occurred in the paper portion, a predetermined amount that is determined in advance is further sent out by the transport roller pair 4.
At this time, a slack is formed in the cut sheet 2 between the registration roller 6 and the conveying roller pair 4, and this slack is absorbed by the portion provided between the paper guide pair 7 with a wide gap, and cut. After the leading edge of the sheet 2 has reached the nip of the registration roller 6, the registration roller 6 is rotated and the cut sheet 2 is sent to the printing unit.

In the second skew correction device in the conventional cut sheet conveying device shown in FIG. 7, the skew roller 8 is arranged between the sheet pickup section and the printing section, and a predetermined cut sheet 9 connecting the skew rollers 8 is provided. The cut sheet 9 is configured to have an inclination of several degrees to several tens of degrees with respect to the transport direction of the cut sheet 9 so as to follow a predetermined cut sheet transport reference plane with respect to the transport direction.

With respect to the second skew correction device in the conventional cut sheet conveying device configured as described above,
The operation will be described below.

The cut sheet 9 picked up is skewed along the sheet guide by the conveying roller 8
Transported to The cut sheet 9 that has reached the skew roller 8 is forcibly conveyed in the direction of the sheet reference plane that is provided in advance by the rotation of the skew roller 8 that is determined in advance. After the corner of the tip of the cut sheet 9 touches the sheet reference surface, the conveyance of the cut sheet 9 causes the cut sheet 9 to continue.
Is sent to the printing unit along the sheet reference surface.

[0010]

However, in the skew correction device using the registration drive roller 6 which is intermittently driven in the conventional cut sheet conveying device shown in FIG. 6, the paper guide always provided in the conveying direction of the cut sheet 2 is provided. A space for forming the slack of the cut sheet 2 is required at the 7th pair, which is a great obstacle to downsizing the main body device.

Further, in the skew correction device using the skew roller 8 shown in FIG. 7, the cut is picked up beyond the sheet reference plane provided in advance for feeding the cut sheet 2. The sheet 2 has no effect, and the skew roller 8 has an adverse effect.

In consideration of the above-mentioned conventional problems, the present invention provides a cut sheet skew correction apparatus which can reduce the size of the main body apparatus without providing a space for forming the slack of the cut sheet between the pair of paper guides. To aim.

[0013]

In order to achieve the above object, the present invention provides a cut sheet conveying mechanism including a paper guide pair for picking up a cut sheet and then sending it to a registration roller via a conveying roller. The gap between the pair is set to be slightly wider than the maximum thickness of the cut sheet to be conveyed and does not cause slack in the cut sheet, and the force that causes the cut sheet to sag is centered on the axis perpendicular to the plane direction of the cut sheet. The skew correction device for a cut sheet is configured to be converted into the rotational force.

According to the present invention, it is possible to provide a cut sheet skew correction apparatus in which the size of the main body apparatus can be further reduced without providing a space for forming the slack of the cut sheet between the pair of paper guides.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention comprises a conveying roller for conveying a cut sheet, a registration roller for starting driving when the leading edge of the cut sheet reaches a nip, In a cut sheet conveying mechanism including a pair of paper guides that guide the cut sheet to the registration roller, skew of the cut sheet causes one tip angle of the cut sheet to reach a nip of the registration roller. From the time until the leading edge completely reaches the nip, the slack of the cut sheet caused by being pressed by the conveyance roller by the conveyance roller is conveyed through the gap between the pair of paper guides. A little wider than the maximum cut sheet thickness that should be It is a skew correction device for a cut sheet that has a spacing that does not cause slack and that converts the force that causes the cut sheet to sag into a rotational force about an axis that is perpendicular to the plane direction of the cut sheet. There is no need to provide a space for making the slack of the sheet between the pair of paper guides, which has an effect that the main body apparatus can be further downsized.

According to a second aspect of the present invention, in the skew correcting apparatus for a cut sheet according to the first aspect, the curved surface of the conveying roller for conveying the cut sheet is pressed against the cut sheet surface in a small area. The cut sheet has a shape or a spherical shape, and has an effect of reducing resistance when the cut sheet is about to rotate and facilitating the rotation.

According to a third aspect of the present invention, in the skew correcting device for a cut sheet according to the first aspect, the pressing of the feed roller for feeding the cut sheet is performed by pressing the center and the left and right edges with respect to the feed direction of the cut sheet. The cut sheets are made different in direction, and the pressure near the center of the cut sheet is made stronger than the pressure in the left and right edge directions of the cut sheet, which reduces the resistance when the cut sheet tries to turn and facilitates turning. Have an effect.

(First Embodiment) The first embodiment of the present invention will be described below. 1 is an external perspective view showing a skew correction device for a cut sheet according to a first embodiment of the present invention. FIG. 2 is a plan view of the same, FIG. 3 is a sectional view of the same, and FIG. Is shown. In addition, the same components as those of the above-described conventional example will be described with the same reference numerals.

In FIGS. 1, 2, 3 and 4, 1
Is a sheet storage member that accommodates a large number of cut sheets and is detachably attached to the apparatus main body, and 2 is a cut sheet that is attached to the sheet storage member 1 in a predetermined amount.

The cut sheet 2 is taken out of the sheet storage member 1 by a feeding means (hereinafter, pickup roller) 3 and a pair of conveying rollers 4 (O) for conveying the cut sheet 2.
Ring). The conveying roller pair 4 is held by the roller bearing 4a, and the conveying roller pair 4 and the cut sheet 2
Pressure is applied between the pressure members 5a and 5b. The cut sheet 2 conveyed by the conveying roller pair 4 is guided downstream to the registration roller 6 which rotates so as to convey the cut sheet 2 in the same direction as the conveying roller pair 4 at a predetermined timing. A pair of paper guide pairs 7 are provided, and the pair of paper guide pairs 7 are
The gap distance is slightly wider than the maximum cut sheet thickness to be conveyed, and is formed with an interval that does not cause slack in the cut sheet 2. The surface contacting the conveyance roller pair 4 is the conveyance roller portion located substantially in the center of the cut sheet. Around the right and left sides, a part is cut off so that the influence of the pressure member does not extend to other than the pair of conveying rollers via the cut sheet. Further, the pressure applied by the pressure members 5a and 5b is 5bf> 5a.
There is a relationship of f.

The operation of the skew correction apparatus for cut sheets constructed as described above will be described below. First, when a paper feed signal for rotating the pick-up roller 3 is output, the pick-up roller 3 rotates, picks up the uppermost part of the cut sheet 2 set in the sheet storage member 1 and transfers it to the pair of conveying rollers 4. Send in. The cut sheet 2 sent out is conveyed downstream along the pair of paper guide pairs 7 by the conveying roller pair 4 and its pressing member (coil compression springs 5a and 5b), and one of the tip angles still indicates a rotation instruction. The sheet reaches the nip of the registration roller 6 which has not been received, and in order to correct the skew of the cut sheet generated in the sheet feeding unit, a predetermined predetermined amount is further sent out by the transport roller pair 4. At this time, in the cut sheet 2, a slack is about to be formed between the registration roller 6 and the conveying roller pair 4, but since there is no space for forming the slack in the gap between the pair of paper guide pairs 7, the slack is previously set to 5 bf. The cut sheet 2 of the pressing member 5 in the four parts of the conveying roller pair having the relation of> 5af.
The cut sheet 2 rotates in a direction in which slack is not formed about an axis that is perpendicular to the sheet surface that passes through the point of pressurization. Then, after all the leading ends of the cut sheet 2 have reached the nip of the registration roller 6, the registration roller 6 is rotated and the cut sheet 2 is sent to the printing unit.

In the first embodiment, the case in which the coil compression spring is used as the pressing means has been described, but the same effect can be obtained by using a leaf spring or a resin spring utilizing the elasticity of resin. Although the O-ring is used as the conveying roller, the same effect can be obtained by using a spherical roller or a roller having a curved contact point to the cut sheet.

Further, in the roller bearing portion, the same effect can be obtained by using a flexible structure using a resin spring to connect the shaft holding portion and its outer periphery as shown in FIG.

[0024]

As is apparent from the above description, according to the present invention, the gap between the pair of paper guides provided between the transport roller and the registration roller is slightly wider than the maximum cut sheet thickness to be transported, In addition, by setting the spacing that does not cause slack in the cut sheet, it is easy to convert the force that causes the cut sheet to generate slack into a rotational force centered on an axis perpendicular to the plane direction of the sheet, and feed it. It is possible to reliably correct the skew that sometimes occurs.

[Brief description of drawings]

FIG. 1 is an external perspective view of a skew correction device for a cut sheet according to a first embodiment of the present invention.

FIG. 2 is a plan view of the skew correction device for the cut sheet.

FIG. 3 is a sectional view of the skew correction device for the cut sheet.

FIG. 4 is a side sectional view of the skew correction device for the cut sheet.

5A is a cross-sectional view of a conveyance roller in a skew correction device for cut sheets according to another embodiment of the present invention, and FIG. 5B is a plan view of the conveyance roller.

FIG. 6 is a sectional view showing a conventional skew correction device using a registration roller.

FIG. 7 is a plan view showing a conventional skew correction device using a skew roller.

[Explanation of symbols]

 1 Sheet Storage Member 2 Cut Sheet 3 Pickup Roller 4 Conveyor Roller Pair 4a Conveyor Roller Bearing 5 Pressurizing Member 5a Coil Compression Spring 5b Coil Compression Spring 6 Registration Roller 7 Paper Guide Pair 8 Skew Roller

Claims (3)

[Claims] 1. A conveying roller for conveying a cut sheet, a registration roller for starting driving when the leading edge of the cut sheet reaches a nip, and a pair of papers for guiding the cut sheet to the registration roller. In a cut sheet conveying mechanism including a guide, from one edge angle of the cut sheet reaches a nip of the registration roller due to skew of the cut sheet until the tip edge completely reaches the nip. In between, the slack of the cut sheet caused by being pressed against the registration roller by the conveyance of the conveyance roller is slightly wider than the maximum cut sheet thickness to be conveyed through the gap between the pair of paper guides, and the cut sheet Make sure that the spacing is set so that there is no slack in the There skew correction apparatus of cut sheets, characterized in that so as to convert the rotational force around an axis perpendicular to the plane direction of the cut sheet a force to be about to occur sagging. 2. The skew correction of the cut sheet according to claim 1, wherein the shape of the cut sheet conveying roller for conveying the cut sheet is a curved surface or a spherical surface that is pressed against the surface of the cut sheet in a small area. apparatus. 3. The pressure of a cut sheet conveying roller for conveying a cut sheet is made different between the center and the left and right edge directions with respect to the cut sheet conveying direction, and the pressure near the center of the cut sheet is more than the pressure in the right and left edge directions of the cut sheet. The skew correction device for a cut sheet according to claim 1, wherein the skew correction device is strong.