JP2008150206A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To hardly cause the displacement of paper even in double-side printing. <P>SOLUTION: This image forming device comprises a printing control means having a printing unit 1A, a first front and rear reversing unit 1B, and a double-side unit 1C and capable of selectively controlling between a single-side printing operation for performing single-side printing on a transfer paper K and a double-side printing operation for performing double-side printing on the transfer paper K. A switchback conveying path HS2 used in the double-side unit 1C is formed in a conveying path reaching the printing unit 1A at a position where there is one bent portion and between a vertical conveying path H0 and a paper discharge port 1D. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is provided with a printing unit capable of printing an image on one side of transfer paper moved upward in a vertical conveyance path from a paper supply unit, and the switchback conveyance in the conveyance path of the transfer paper printed by the printing unit. A first front / back reversing unit is provided that reverses the front and back by moving the path and feeds the transfer paper to the discharge port side in a state of alignment in the width direction, and is printed on one side by the printing unit. The transfer paper is turned upside down by moving the switchback conveyance path in the conveyance path, and the transfer paper is recirculated to the printing unit with the alignment in the width direction of the transfer paper, and the other side is also printed. A single-sided printing operation in which a double-sided unit is provided, and the printing unit and the first front / back reversing unit are used to perform single-sided printing on the transfer paper; Knit and relating to the image forming apparatus and a duplex printing operation switch controllable printing control means is provided for performing duplex printing using the duplex unit to the transfer paper.

Conventionally, in this type of image forming apparatus, as shown in FIG. 6, the printing unit 1A and the first front and back are reversed along the movement path of the transfer sheet K that has moved up the vertical conveyance path H0 from the paper supply unit 1E. There is a unit that includes the unit 1B and the double-sided unit 1C (for example, see Patent Document 1).
That is, the first front / back reversing unit 1B includes a first conveyance path H1 provided in a state in which a laterally arranged conveyance path passing through the printing unit 1A wraps downward, and a transfer paper at the end of the first conveyance path H1. A horizontal switch-back first transport path HS1 that switches back and reverses K and a second transport path H2 that transports the switch-backed transfer paper K toward the paper discharge port 1D are provided. . A width adjusting mechanism 2 is provided for aligning the transfer paper K that has entered the first switchback transport path HS1 in the paper width direction so that the transfer paper K is supplied straight along the transport path. ing.
On the other hand, the double-sided unit 1C uses both the first transport path H1 and the first switchback transport path HS1 in the form of the first front / back reversing unit 1B, and the first switchback transport A fourth transport path H40 for reciprocally moving the transfer sheet K reversed in the front-rear direction in the path HS1 to the printing unit 1A is provided, and the fourth transport path H40 is the second transport path H40 of the first front / back reversing unit 1B. It is provided as a separate path that wraps downward from the second transport path H2 and returns to the vertical transport path H0 side, then wraps upward again, joins the vertical transport path, and reaches the printing unit 1A.
That is, the switchback transport path HS1 used in the duplex unit 1C is configured so that there are two bent portions in the transport path reaching the printing unit 1A.

JP 2002-174935 A (FIG. 1)

In the image forming apparatus, it is important to feed the transfer paper in a posture along the transport path so as not to be laterally shifted from the viewpoint of preventing printing distortion or paper jam. According to the conventional image forming apparatus, when double-sided printing is performed, the transfer paper is positioned by the width adjusting mechanism and then passes through the two bent conveyance paths.
However, the lateral deviation or inclination of the transfer paper is likely to occur at the bent portion of the conveyance path, and the conventional product that passes through the two bent conveyance paths has a problem that the positional deviation of the paper is likely to occur.

  Accordingly, an object of the present invention is to provide an image forming apparatus which solves the above-described problems and hardly causes paper misalignment even in double-sided printing.

  A first characteristic configuration of the present invention is provided with a printing unit capable of printing an image on one side of a transfer sheet moved upward in a vertical conveyance path from a paper feed unit, and conveys the transfer sheet printed by the printing unit. There is provided a first front / back reversing unit that reverses the front and back by moving the switchback conveying path in the path and sends the transfer paper to the discharge port side in a state of alignment in the width direction. The transfer paper printed on the surface of the transfer paper is reversed on the front and back by moving the switchback conveyance path in the conveyance path and moved to the printing unit again in a state in which the alignment in the width direction of the transfer paper is performed, Single-sided printing in which a double-sided unit is provided for printing on the other side, and single-sided printing is performed on the transfer paper using the printing unit and the first front / back reversing unit. And an image forming apparatus provided with a print control means capable of switching between a printing operation and a duplex printing operation for performing duplex printing on the transfer paper using the printing unit and the duplex unit. The switchback conveyance path to be used is located at a position where there is only one bent portion in the conveyance path reaching the printing unit, and within a range between the vertical conveyance path and the paper discharge port. is there.

According to the first characteristic configuration of the present invention, the switchback conveyance path used in the duplex unit is installed at a position where the bending portion in the conveyance path reaching the printing unit is one, so that the switchback conveyance is performed. The transfer paper that has been width-aligned in the path will pass through only one bend before moving to the duplex unit, so the number of bends can be reduced compared to conventional products, and the orientation of the paper even when printing on both sides. It becomes easy to maintain the straight.
In addition, since the switchback conveyance path used in the duplex unit is installed in a range between the vertical conveyance path and the discharge port, it is accommodated within the apparatus width of the conventional product, and the above-described effects are obtained. It can be prevented that the width dimension of the apparatus is increased while being realized.
As a result, it is easy to prevent printing misalignment, paper jams, and the like without increasing the size of the apparatus.

  According to a second characteristic configuration of the present invention, the switchback conveyance path used in the first front / back reversing unit and the switchback conveyance path used in the double-sided unit are on the front end side in the entrance direction of the transfer paper to each. A width alignment mechanism that is provided in a communicating state and performs alignment in the paper width direction in both switchback conveyance paths is also used.

  According to the second characteristic configuration of the present invention, in addition to achieving the above-described operation and effect of the first characteristic configuration of the present invention, a width for performing alignment in the paper width direction in both switchback conveyance paths. Since the alignment mechanism is also used, the apparatus configuration can be minimized and the cost increase can be suppressed. Further, since the space inside the apparatus can be saved, it is easy to prevent the apparatus from becoming large.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the parts indicated by the same reference numerals as those in the conventional example indicate the same or corresponding parts.

FIG. 1 shows an embodiment of an image forming apparatus according to the present invention. The image forming apparatus 1 is configured as, for example, a copier, a facsimile, a printer, or the like.
The image forming apparatus 1 is provided with a printing unit 1A capable of printing an image on one side of a transfer sheet K moved along a conveyance path H, and the transfer sheet K printed by the printing unit 1A is conveyed along the conveyance path H. A first front / back reversing unit 1B that reverses the front and back and feeds it to the paper discharge port 1D side is provided, and the transfer paper K printed on one surface by the printing unit 1A is moved along the transport path H. A double-sided unit 1C that reverses the front and back and moves to the printing unit 1A again in a state in which the transfer paper K is aligned in the width direction and is ready to print on the other side is provided, and the printing unit 1A And the first front / back reversing unit 1B and the single-sided printing operation for performing single-sided printing on the transfer paper K, and the printing unit 1A and the double-sided unit 1C. Serial transfer sheet switch controllable printing control means and a double-sided printing operation for performing duplex printing to K (not shown) is formed is provided.
Incidentally, in each transport path H, a transport mechanism T such as a plurality of guide members for guiding the transfer paper K along the transport path and a plurality of roller members 3 for transporting and driving the transfer paper K along the transport path. Is provided. The roller members 3 are controlled according to a predetermined transport pattern by the above-described printing control means.

  As shown in FIG. 1, the printing unit 1 </ b> A is configured to be able to print on the upper surface of the transfer paper K that has moved along a vertical conveyance path H <b> 0 that extends upward from the paper supply unit 1 </ b> E.

The first front / back reversing unit 1B includes a first reversing mechanism that reversely conveys the transfer sheet K from the first conveying path H1 to the second conveying path H2 via the first switchback conveying path HS1. .
Incidentally, the first transport path H1 is a transport path H provided in a state extending from the printing unit 1A to the first front / back reversing unit 1B, and the second transport path H2 is from the first front / back reversing unit 1B. This is a conveyance path H provided in a state extending over the sheet discharge outlet 1D.
The first front / back reversing unit 1B prints an image on the one surface of the transfer paper K by the printing unit 1A, and then discharges the transfer paper K from the paper discharge port 1D. By reversing the front and back of the transfer paper K through the back conveyance path HS1 to the second conveyance path H2, the print surface can be discharged downward, and the overlap of the printed transfer sheets discharged one after another is the same as the arrangement of the originals. It is configured to be used if you want to be.
The first switchback transport path HS1 is provided with a width adjusting mechanism 2 for adjusting the position in the paper width direction and the paper posture along the transport direction with respect to the transferred transfer paper K. The width adjusting mechanism 2 By adjusting the width of the transfer sheet K, the transfer sheet K can be advanced in a straight position (position along the transport direction) at a predetermined position (position in the width direction) in the transport path.
As a result, paper jams can be prevented and the overlap of the transfer paper K discharged from the paper discharge port 1D can be easily aligned.

The duplex unit 1C includes a second reversing mechanism that reversely conveys from the third conveying path H3 to the fourth conveying path H4 via the second switchback conveying path HS2.
Incidentally, the third transport path H3 is provided in a state extending from the printing unit 1A to the duplex unit 1C, and is partly shared with the first transport path H1, and then wraps downward to the vertical transport path. Returning to the H0 side, the transfer path H reaches the second switchback transfer path HS2 again by turning upward, and the fourth transfer path H4 is one bent portion from the first switchback transfer path HS1. The conveyance path H is provided so as to communicate with the printing unit 1A.
The duplex unit 1C has a function of inverting the front and back of the transfer sheet K in the process of being transported through the transport path H in the image forming apparatus 1, and the printing unit 1A prints an image on one surface. The transferred transfer paper K is turned over and moved to the printing unit 1A so as to be printed on the other side (double-sided printing).
Incidentally, the second switchback conveyance path HS2 and the first switchback conveyance path HS1 are configured in a continuous manner with the transfer paper K entering the opposite direction, but the width of the transfer sheet K is reversed when the transfer paper K is reversed. The alignment mechanism 2 can also be used. Therefore, the transfer paper K that has entered the second switchback transport path HS2 from the third transport path H3 is aligned by the width adjusting mechanism 2 and straightens a predetermined position (position in the width direction) on the transport path. The transfer sheet K can be advanced to the printing unit 1A with a proper posture (position along the transport direction).
As a result, paper jam can be prevented.
Further, in the fourth transport path H4 to the printing unit, since there is only one bent portion, it is difficult for the transfer paper K to be laterally displaced or distorted, and printing distortion can be prevented.

An outline of typical transfer forms of the transfer paper K in the image forming apparatus 1 will be described in the following three types. However, there are cases where other transport modes are used, but the description thereof is omitted.
[1] The paper is conveyed from the paper supply unit 1E to the printing unit 1A and discharged from the paper discharge port 1D. That is, it is conveyed in the order of (a) to (b) to (h) to (i) in FIG.
[2] The paper is conveyed from the paper supply unit 1E to the printing unit 1A, and the first front / back surface reversing unit 1B reverses the front and back surfaces of the transfer paper K, and then is sent to the paper discharge port 1D for discharge. That is, it is conveyed in the order of (a) to (b) to (c) to (f) to (j) to (i) in FIG.
[3] The paper is transported from the paper supply unit 1E to the printing unit 1A, and the front and back surfaces of the transfer paper K are reversed by the duplex unit 1C, and then sent to the printing unit 1C again and discharged from the paper discharge port 1D. That is, in FIG. 4, (a) to (b) to (c) to (d) to (e) to (f) to (g) to (b) to (h) to (i) are conveyed in this order. Is done.

According to the image forming apparatus 1 of the present embodiment, the transfer paper K that has been width-aligned in the second switchback transport path HS2 only passes through one bent portion before moving again to the printing unit 1A. Therefore, the number of bent portions can be reduced as compared with the conventional product, and the posture of the paper can be easily maintained straight during double-sided printing.
In addition, the above-described effects can be achieved within the width of the conventional apparatus.
As a result, it is easy to prevent printing misalignment, paper jams, and the like without increasing the size of the apparatus.
Further, since the width adjusting mechanism 2 for performing alignment in the paper width direction in both switchback transport paths HS1 and HS2 is also used, it is possible to minimize the apparatus configuration and to suppress an increase in cost. Become. Further, since the space inside the apparatus can be saved, it is easy to prevent the apparatus from becoming large.

[Another embodiment]
Other embodiments will be described below.

<1> The image forming apparatus 1 is not limited to the apparatus configuration described in the previous embodiment, and may adopt another known apparatus configuration. Therefore, the structure by a different unit may be sufficient.
<2> In the previous embodiment, the second switchback transport path HS2 has been described as being disposed horizontally at a position continuous with the first switchback transport path HS1, but the second switchback transport path HS2 is not limited to that configuration. Instead, for example, as shown in FIG. 5, it may be provided in a vertical arrangement in a part of the vertical conveyance path H0.

  In addition, as mentioned above, although the code | symbol was written in order to make contrast with drawing convenient, this invention is not limited to the structure of an accompanying drawing by this entry. In addition, it goes without saying that the present invention can be carried out in various modes without departing from the gist of the present invention.

Schematic diagram illustrating each configuration in the image forming apparatus Schematic diagram showing an example of transport mode Schematic diagram showing an example of transport mode Schematic diagram showing an example of transport mode Schematic diagram illustrating each configuration in the image forming apparatus of another embodiment Schematic diagram illustrating each configuration in a conventional image forming apparatus

Explanation of symbols

DESCRIPTION OF SYMBOLS 1A Printing unit 1B 1st front-back reversing unit 1C Duplex unit 1D Paper discharge port 1E Paper feed part 2 Width adjustment mechanism H0 Vertical conveyance path HS1 First switchback conveyance path HS2 Second switchback conveyance path K Transfer paper

Claims (2)

A printing unit capable of printing an image is provided on one side of the transfer paper that has moved up the vertical conveyance path from the paper supply unit, and the transfer paper printed by the printing unit is moved along the switchback conveyance path in the conveyance path. A first front / back reversing unit is provided for reversing the front and back and sending the transfer paper to the discharge port side in a state where the transfer paper is aligned in the width direction, and the transfer paper printed on one side by the printing unit is provided. By moving the switchback conveyance path in the conveyance path, the front and back are reversed and the transfer paper is moved around to the printing unit in a state where the width direction of the transfer paper is aligned, so that the other side can be printed. A double-sided unit, a single-sided printing operation for performing single-sided printing on the transfer paper using the printing unit and the first front / back reversing unit; and the printing unit Serial An image forming apparatus switching controllable printing control means is provided with a duplex printing operation for performing duplex printing on the transfer paper using the duplex unit,
The switchback conveyance path used in the duplex unit is installed at a position where there is one bend in the conveyance path reaching the printing unit and within a range between the vertical conveyance path and the paper discharge port. Image forming apparatus.   The switchback conveyance path used in the first front / back reversing unit and the switchback conveyance path used in the double-sided unit are provided in a state where they are communicated with each other on the front end side in the entrance direction of the transfer paper to both. The image forming apparatus according to claim 1, wherein a width alignment mechanism for performing alignment in the paper width direction in the switchback conveyance path is also used.

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