JP2954213B1 - Double-sided printing device - Google Patents

Abstract

Provided is a double-sided printing apparatus that corrects skew and suppresses lateral displacement of front and back side printing. SOLUTION: A transport route is provided linearly and a first straight transport route 12a passing through an image forming unit.
And an R-shaped conveyance route 12b connected to the first straight conveyance route 12a and provided so as to be curved toward the upper portion of the first straight conveyance route, and a first straight A second straight transport route 12c provided in a straight line substantially parallel to the transport route, an end of the second straight transport route, and a first straight transport route.
And an S-shaped transport route 13 which is connected to the end of the straight transport route.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-sided printing apparatus, and more particularly to a two-sided printing apparatus capable of correcting skew while reversing a sheet.

[0002]

2. Description of the Related Art FIG. 3 shows a schematic diagram of a conventional double-sided printing apparatus. In this example, an electrophotographic printer includes a registration roller, a transfer roller / OPC (organic photoconductor) drum, a fixing roller, and the like, and separately includes a duplex unit for printing on both sides. The duplex unit has a separate transport route, and has a reversing roller for reversing the front and back of a sheet.

As a conventional example of the above-mentioned double-sided printing apparatus, a single-sided copied sheet is moved while rapidly changing its direction so as to face a sheet feeding unit. The sheet fed into the sheet storage unit at a distance more than the sheet width does not interfere with either the sheet receiver for sheet alignment or the member for pressing the sheet, and further, the sheet material is aligned to the reference position by the intermediate tray. By preventing skew, feeding failure, and reference position failure, or by stacking sheets on a sheet receiving member, the sheet is straightened by the sheet guide member and the width is regulated by the sheet regulating member. and so on.

[0004]

In the above-mentioned conventional example,
In double-sided printing of electrophotography, there is a problem that the skew amount tends to increase because the transport route is longer than in single-sided printing.

[0005] There is also a problem that lateral misalignment is likely to occur during front side printing and back side printing.

Further, particularly when the paper is turned over, the skew direction of the front side and the back side is switched as shown in FIG.

Accordingly, an object of the present invention is to provide a double-sided printing apparatus which corrects skew when a sheet is reversed in double-sided printing and suppresses a lateral shift between front and back side printing in order to solve the above problem.

[0008]

To achieve the above object, a double-sided printing apparatus according to the present invention is directed to a double-sided printing apparatus having a transport route for transporting a sheet, wherein the transport route is provided in a straight line and the image forming is performed. To connect a first straight transport route passing through the unit, a second straight transport route substantially parallel to the first straight transport route, and one end of the first and second straight transport routes, In order to connect the curved R-shaped conveyance route and the other ends of the first and second straight conveyance routes, the R-shaped conveyance route is formed in an S-shape with respect to the paper conveyance direction of the first and second conveyance routes. S-shaped conveyance route, and the paper
When the paper is conveyed in the order of the straight conveyance route, the R-shaped conveyance route, the second straight conveyance route, the S-shaped conveyance route, and the first straight conveyance route, the paper is naturally inverted and the back surface and the front surface are printed. It is characterized by eliminating displacement.

It is preferable that the paper transport direction in the first and second straight transport routes and the paper transport direction in the S-shaped transport route are substantially perpendicular.

[0010] Further, a first lift roller for vertically transporting the sheet and transporting the sheet on the S-shaped transport route on which the sheet is transported from the second straight transport route, and an S-shaped transport route. It is preferable that a second lift roller is provided on the first straight transport route on which the paper is transported so as to be vertically movable and transport the paper.

Further, the second lift roller is rotatable so as to convey the sheet in the sheet conveying direction of the S-shaped conveying route and then to convey the sheet in the sheet conveying direction of the first straight conveying route. preferable.

Further, when a sheet is conveyed from the S-shaped conveyance route to the first straight conveyance route, it is preferable to provide a side guide for abutting a lateral edge of the sheet to correct a lateral shift.

It is preferable that the side guide is provided outside the first straight transport route.

Further, a first straight transport route,
It is preferable to provide a switching gate for switching between a path for transporting to the R-shaped transport route for duplex printing and a path for discharging paper to the stacker between the R-shaped transport route.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing the structure of an embodiment of a double-sided printing apparatus according to the present invention. This apparatus has a paper transport route 12 and an S-shaped transport route 13. Paper transport route 1
2 has a first straight transport route 12a, an R-shaped transport route 12b, and a second straight transport route 12c, and the S-shaped transport route 13 has a second
Is provided between the first straight transport roller 12c and the first straight transport roller 12a, and transports the sheet in the vertical direction from the second straight transport roller 12a to the straight transport roller 12c.

The first straight transport route 12a
A switching gate 4 provided after the conveying roller (lower) 1, the registration roller 2, the image forming unit 3, and the image forming unit 3 is disposed in the image forming unit. Further, on the extension of the first straight transport route 12a, a transport route for discharging the sheet exiting from the switching gate 4 to the stacker is provided. The R-shaped transport route 12b is a route for performing double-sided printing, and is a first straight transport route 12b.
a to the second straight transport route 12c. After the R-shaped transport route 12b, there is a second straight transport route 12c and an S-shaped transport route 13 in a direction perpendicular to the paper transport direction in which image formation is performed. A transport roller 5 for transporting a sheet is disposed on the second straight transport route 12c. The S-shaped transport route 13
At the entrance, a first lift roller 6 which is movable in the vertical direction and transports the paper perpendicularly to the transport direction of the S-shaped transport route 13, and transports the paper near the intermediate point. And a second lift roller 8 for transporting the sheet so as to be vertically movable with respect to the S-shaped transport direction and rotatable by 90 degrees in the rotation direction 9 at the outlet. At the end, a side guide 10 for correcting a skew that can be moved in the movement direction 11 is arranged.

Next, the operation of the embodiment of the present invention will be described with reference to FIG. First, the sheet conveyed to the conveying roller (lower) 1 and the registration roller 2 is image-formed by the image forming unit 3 and one-side printing is performed. When performing double-sided printing, the paper is guided to the R-shaped transport route 12 b by the switching gate 4 and transported by the transport roller (upper) 5. Then, after the trailing edge of the paper has passed through the nip of the transport roller (upper) 5, the first lift roller 6 waiting above the second straight transport route 12c is lowered, and the first lift roller 6 6, the first lift roller 6 is rotated, and the sheet is transported in the horizontal direction by the S-shaped transport route 13. At the intermediate point of the S-shaped transport route 13, the paper is transported by the transport roller 7. Then, after the sheet is conveyed along the S-shaped conveyance route 13, the second lift roller 8 that has been waiting above the first straight conveyance route 12 a is lowered to apply the second lift roller 8 to the sheet, The second lift roller 8 is rotated to convey the sheet, and the lateral edge of the sheet is skewed by abutting the side edge of the sheet against a side guide 10 movable in a moving direction 11 previously adjusted to the sheet width by a driving source such as a motor. Is corrected.

FIG. 2 is a perspective view showing a state where the lift roller is rotated in the embodiment of the duplex printing apparatus of the present invention. The second lift roller 8 is raised, and the second lift roller 8 is rotated at a position shown in FIG. 2 by 90 degrees in the direction of rotation 9 by a drive source such as a motor. Then, the second lift roller 8 is lowered, and the sheet is conveyed by applying the second lift roller 8 to the sheet. By this series of operations, the sheet is reversed and skew is corrected. In particular, skew is effective for printing deviation on the front and back surfaces. After that, the paper is sent to the conveying roller (lower) 1, the registration roller 2, and the image forming unit 3 in the same manner as the one-sided printing, and the two-sided printing is performed.
The sheet is guided to the stacker by the switching gate 4. The first lift roller 6 and the second lift roller 8 are
Before the next sheet is conveyed, the sheet rises above the conveyance route, rotates 90 degrees in the direction opposite to the rotation direction 10 only for the second lift roller 8, and returns to the position in FIG. In addition, the side guide 10 waits at a position wider than the sheet width so as not to hinder the sheet conveyance during the one-sided printing.

[0020]

As described above, according to the present invention, in double-sided printing, there is an effect that skew can be corrected while reversing the sheet.

As for the correction of skew, the lateral edge of the sheet is abutted against the side guide, so that there is an effect that the lateral deviation of the printing on the front side and the back side can be processed.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of an embodiment of the present invention.

FIG. 2 is a perspective view showing a state when a second lift roller of FIG. 1 is rotated.

FIG. 3 is a schematic diagram showing a configuration of a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 conveyance roller (lower) 2 registration roller 3 image forming unit 4 switching gate 5 conveyance roller (upper) 6 first lift roller 7 conveyance roller (middle) 8 second lift roller 9 rotation direction 10 side guide 11 movement direction 12a First straight transport route 12b R-shaped transport route 12c Second straight transport route 13 S-shaped transport route

Claims (7)

(57) [Claims] 1. A double-sided printing apparatus having a transport route for transporting a sheet, wherein the transport route includes a first straight transport route that is provided in a straight line and passes through an image forming unit, and a first straight transport route. A substantially parallel second straight transport route; an outwardly curved R-shaped transport route for connecting one end of the first and second straight transport routes; and the first and second straight routes. And an S-shaped transport route formed in an S-shape with respect to the paper transport direction of the first and second transport routes to connect the other end of the transport route. The sheet is conveyed in the order of the first straight conveyance route, the R-shaped conveyance route, the second straight conveyance route, the S-shaped conveyance route, and the first straight conveyance route. When double-sided printing apparatus characterized by lost backside, the print displacement of the surface reversed the sheet naturally. 2. A paper conveying direction in the first and second straight conveying routes is substantially perpendicular to a paper conveying direction in the S-shaped conveying route.
The double-sided printing device according to claim 1. 3. A first lift roller for transporting a sheet in a vertically movable manner on the S-shaped transport route on which the sheet is transported from the second straight transport route; A second lift roller for vertically moving the sheet and conveying the sheet on the first straight conveyance route on which the sheet is conveyed from the character conveyance route. Item 3. The double-sided printing device according to item 1 or 2. 4. The apparatus according to claim 1, wherein the second lift roller is rotatable so as to convey the sheet in the sheet conveying direction of the S-shaped conveying route and then convey the sheet in the sheet conveying direction of the first straight conveying route. 4. The double-sided printing apparatus according to claim 3, wherein: 5. When a sheet is conveyed from the S-shaped conveyance route to the first straight conveyance route, a side guide for abutting a lateral edge of the sheet is provided to correct a lateral shift. A double-sided printing apparatus according to any one of claims 1 to 4. 6. A double-sided printing apparatus according to claim 5, wherein said side guide is provided outside said first straight conveyance route. 7. The printing apparatus according to claim 1, wherein the first straight transport route and the R-shaped transport route are provided with a plurality of R-shaped transfer routes for duplex printing.
The double-sided printing apparatus according to any one of claims 1 to 6, further comprising a switching gate for switching between a path for conveying the sheet to the shape conveying route and a path for discharging the sheet to the stacker.