KR19990038171A - Paper reversing unit of duplexer - Google Patents

Abstract

The present invention relates to a paper reversing device of a double-sided printing device, comprising a reversing roller consisting of three rollers, wherein the driven rollers are engaged up and down with one driving roller as a center, and the paper reversing lever is in the axial direction of the driving roller. The rollers are installed at equal intervals, and the feed rollers are engaged with the rollers located on the outside of one of the pair of discharge rollers. Share the path between the roller and the reversing roller.

Description

Paper reversing device for duplexer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a duplex printing apparatus in an apparatus using an electrophotographic developing method, and more particularly, to a paper reversing apparatus for duplex printing.

There are office equipment such as laser beam printers, copiers, printers, and facsimile machines using the electrophotographic development method. Among them, copiers or printers are provided with a single-sided or double-sided printing function using plain paper. An example of a duplex printing apparatus having a method of printing only one surface of a sheet and a function of printing both sides of a sheet of the copy function at the same time will be described.

1 is a configuration diagram schematically showing a duplex printing apparatus for printing on both sides of a paper according to a conventional embodiment. 2 is an enlarged view illustrating main parts of FIG. 1. Referring to the drawings,

The conventional duplex printing apparatus sets the single-sided printing function on the machine.

First, a plurality of sheets of paper are loaded into the paper feed cassette 10, and after the sheets are set, the sheets are sequentially fed sheet by sheet by the pick-up roller 20 by frictional force. The conveyed paper passes through the paper guide 22, passes through the alignment roll roller 30, and then passes through the developing unit 40 and passes through the fixing unit 50 to fix the toner on the paper. The sheet having passed through the fixing unit 50 continues to pass through the discharge roller 60.

At this time, the method of printing only one side of the paper is discharged immediately passing through the final reverse roller 70. At least one reverse roller 70 is installed at equal intervals in the axial direction. When the reversing roller 70 is single-sided printing, the paper passes naturally because the lever 65 maintains a solid line state. The inversion roller 70 rotates in one direction.

On the other hand, the method of printing paper on both sides sets the duplex printing function on the machine. At this time, the lever 65 maintains a dotted line state.

The paper passing through the fixing unit 50 passes through the discharge roller 60 and reaches the paper guide lever 65. The paper path is determined by the lever 65, and the paper arrives at the reversing roller 70. Then, when the rear end of the paper printed on only one surface is detected by an optical sensor not shown in the drawing, the reverse roller 70 reverses rotation by the sensor's instruction, and according to the rotation, the paper P passes through another paper path. To the pickup roller 20 by the transfer rollers 80 and 90. The sheet is sequentially conveyed by the pickup roller 20, and the conveyed paper is guided by the guide 22 through the developing device 40, and after the optical sensor detects the leading edge of the paper, the lever 65 is turned counterclockwise. By the reversing roller 70 and discharged to the discharge bin. An arrow marked with a thick solid line in the paper path is a path through which printing is moved only on one side, and an arrow marked with a thick dotted line indicates a movement path with the paper printed on only one side being reversed.

The printing process is performed on one or both sides of the paper in the same manner as described above.

However, in the above two-sided printing method, a guide, which is an additional paper path, is required in order for the paper past the lever to return to the initial state again by reverse rotation of the reversing roller. These paper paths have become more compact because they take up more space than necessary in the instrument set.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a paper reversing apparatus of a duplex printing apparatus which is advantageous for set compaction in pursuit of only one path when reversing paper.

In order to achieve the above objects, the present invention comprises a reversing roller consisting of three rollers, with the driven rollers engaged up and down with one driving roller as a center, and the paper reversing lever in the axial direction of the driving rollers at equal intervals. The feed roller is installed to engage with the roller located on the outside of one of the pair of discharge rollers, and the selection of the drive roller and the driven roller is determined according to the rotation of the lever so that the paper path is reversed from the discharge roller when the paper is reversed. Share the path between the rollers.

1 is a schematic view showing a duplex printing apparatus according to a conventional embodiment

2 is an enlarged view illustrating main parts of FIG. 1;

Figure 3 is a schematic view showing a duplex printing apparatus according to an embodiment of the present invention

4 is an enlarged view illustrating main parts of FIG. 3;

<Description of Symbols for Main Parts of Drawings>

601,602: Badge roller 701: Driving roller

702,703: driven roller 704: paper reversing lever

603: feed roller

Hereinafter, with reference to the accompanying drawings will be described in detail the most preferred embodiment of the present invention. First, in describing each of the drawings, only the same components have the same reference numerals as much as possible even if shown on different drawings. In describing the present invention, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Figure 3 is a schematic diagram showing a duplex printing apparatus according to an embodiment of the present invention. 4 is an enlarged view illustrating main parts of FIG. 3. In the drawings, a double-sided printing apparatus having a single-sided printing function and a double-sided printing function among laser beam printers using an electrophotographic developing method will be described as an example. Referring to the drawings,

Referring to the duplex printing apparatus of the present invention, in order to implement a single-sided printing or a two-sided printing process, the lever 704, which is a separate device, is installed on the reverse roller 70, and the discharge roller 60 and the reverse roller 70 for single-sided printing or duplex printing. Maximize the shared paper path by sharing the guide 62 located between them.

The reversing roller 70 is composed of three rollers 701, 702 and 703, and at least one lever 704 is rotatably installed between the axes of the driving rollers installed in the same direction. The reversing roller 70 engages two driving rollers 702 and 703 up and down with one driving roller 701. The driven rollers 702, 703 also rotate simultaneously with the rotation of the yarn drive roller 701. One driven roller 702 is used for discharging, and the other driven roller 703 is used for reversing paper.

The paper reversing means of the laser beam printer for reversing the paper will be described in detail with reference to the whole apparatus.

The paper feed cassette 10 in which a plurality of sheets are loaded is placed on the bottom of the machine set, the pickup roller 20 is positioned on the front of the paper cassette, the paper path is determined by the guide 22 guiding the paper path, and then the alignment roller. 30 is installed. The front end of the sheet is aligned by the alignment roller 30, and the developing unit 40 and the fixing unit 50 are provided in order so that an image is formed in the sheet having passed the pair of alignment roller 30. The fixing unit 50 is a heating roller 501 is located on the top of the known fact, the compression roller 502 is located on the bottom. The toner is fixed on the paper by the high heat and high pressure of the fixing unit 50.

A pair of discharge rollers 601, 602 are provided so that only one surface on which the paper path is guided is discharged to the outside. The guide 62 is installed so that the sheet passing the discharge roller 60 faces the reversing roller to determine the paper path.

At this time, the reversing roller 70 is installed in the final position consists of three rollers, one driven roller 702, 703 each is installed up and down around the driving roller 701. That is, the driven rollers 702 and 703 are engaged with each other around the driving roller 701. In accordance with the rotation of the drive roller 701, the driven rollers 702, 703 rotate simultaneously.

At least one driving roller 701 is provided at equal intervals in the axial direction, and driven rollers 702 and 703 correspond to the driving roller. At least one lever 704 is provided between the drive rollers 701 in the axial direction. The lever 704 is rotatable about a hinge axis 7041.

Therefore, the printing process of one side or both sides of the paper proceeds by passing between the upper and lower driven rollers with respect to the driving roller 701 as the lever 7041 rotates.

In addition, the other conveying rollers 603 are engaged with each other in the outward direction of the discharge rollers 60, so that the reversed paper is conveyed through between the rollers 602 and the conveying rollers 603 of the discharge rollers. Moreover, the guide 62 between the discharge roller 60 and the reversing roller 70 is a shared paper path. Compared to the existing length of paper sharing path is maximized. The longer the length of the paper path is shared, it is advantageous for the miniaturization of the equipment set and the manufacturing cost is reduced.

Referring to the operation of the duplex printing apparatus of the present invention according to the above configuration,

A plurality of sheets of paper are loaded into the paper feed cassette 10, and then the sheet P at the top of the sheet is sequentially conveyed by the pickup roller 20 and fingers not shown in the drawings. After the leading edge of the paper reaches the alignment roller 30, the leading edge of the paper is aligned, and then the toner is fixed on the paper while passing through the developing unit 40 and the fixing unit 50.

Such paper has only one side printed. On this basis, the process of printing on one side and the process of printing on both sides will be described separately.

In the simplex printing process, in order to implement the simplex printing process, first of all, by pressing a button on the operation panel, the simplex printing execution signal is output from the controller to set the simplex printing function in the apparatus. When the cross-sectional printing function from the controller is set, the lever 704 provided between the final drive rollers 701 maintains the solid state in the drawing.

After the developing process 40, the process of forming an image progresses, passes through the fixing unit 50, and the paper on which only one surface on which the toner is fixed is formed passes through the pair of discharge rollers 60, and then the paper path is guided by the guide 62. The paper passing through the guide 62 is discharged to the discharge bin by the reversing roller. As already described, the paper path is discharged in the direction indicated by the solid line because the lever 704 rotating about the hinge axis is in the state indicated by the solid line in the figure. The reverse roller 70 is discharged through the driving roller 701 and the driven roller 702.

On the other hand, when describing the duplex printing process, by pressing a button on the operation panel to implement the duplex printing process first, the duplex printing execution signal is issued from the controller to set the duplex printing function on the device. When the duplex printing function from the controller is set, the lever 704 provided between the final drive rollers maintains a dotted line in the drawing.

The paper on which only one surface has passed through the developing unit 40 and the fixing unit 50 passes through a pair of discharge rollers 60, and the paper path is guided by the guide 62. When the paper arrives at the reversing roller 70, the driving roller 701 and the driven roller 703 rotate in engagement with each other, and the paper is reversed by the rotation of the rollers. At the same time, the paper path is guided by the guide even when the paper is reversed. The reversed moving path is a shared paper path.

The paper is then moved along the path represented by the dotted line, and is moved by the feed roller 603. The conveying roller 603 is rotated in engagement with one of the rollers 602 of the discharge roller to convey the printed paper on only one surface. The sheet having passed through the conveying roller 603 is continuously conveyed to the pickup roller by another conveying roller 80,90. The paper arrives at the alignment roller 30 by the pickup roller 20, and after the leading ends of the paper are aligned, the printing process is performed on the opposite side of the printing surface of the paper while passing through the developing unit 40 and the fixing unit 50. The paper on which both sides are printed passes through the discharge roller 60, and the front end of the paper is sensed by a sensor (not shown), and the lever 704 is rotated to be in a solid line state, and thus the paper is discharged to the discharge bin by the rollers 701 and 702.

At this time, the sensor is most preferably an optical sensor, the sensor is most preferably installed between the fixing unit 50 and the discharge roller 60. Further, the paper guide 62 between the discharge roller 60 and the reversing roller 70 is preferably formed slightly larger than the length of the sheet.

On the other hand, in the detailed description of the present invention has been described with respect to specific embodiments, it will be apparent to those skilled in the art that various modifications are possible without departing from the scope of the present invention.

As described above, the present invention maximizes the paper path that can be shared in a laser beam printer of an electrophotographic processor using an electrophotographic development method, particularly in a laser beam printer capable of selecting a single-sided printing function and a two-sided printing function. Effective for miniaturizing sets

Claims (3)

Among the laser beam printers, a single-sided printing function and a double-sided printing function are provided with a lever rotating about a hinge axis and forward or reverse rotation, and at least one reversing roller installed at equal intervals in the axial direction. In the paper duplex printing apparatus optionally provided with: The reversing roller is composed of three rollers, and the driven rollers are engaged with each other up and down with one driving roller as the center, and the paper reversing levers are installed at equal intervals in the shaft in the axial direction of the driving roller, and a pair of discharge media is provided. The transfer roller is installed to be engaged with the roller located outside one of the rollers, and the selection of the drive roller and the driven roller is determined by the rotation of the lever so that the paper path shares the path between the discharge roller and the reversing roller when the paper is reversed. Paper reversing device of the duplex printing apparatus characterized in that. The apparatus of claim 1, wherein the length of the shared guide is greater than the total length of the paper so that the paper can be reversed. The paper reversing device of claim 1, wherein the paper reversing lever is provided in at least one axial direction between the axes of the drive rollers.