JP2007197108A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the size of a device, simplify paper carrying control and increase the speed of image forming processing. <P>SOLUTION: This image forming device 11 is provided with a mechanism for forming images on both sides of paper, and further provided with a paper feeding means for feeding paper, an image forming part 13 for forming images on the paper fed by the paper feeding means, and a paper inverting and feeding means 15 for inverting paper 14 having an image formed on one face 22 by the image forming part 13 and refeeding the paper 14 to the image forming part 13. The paper inverting and feeding means 15 is provide with a spiral paper storing means 16 for temporarily storing the paper 14 having an image formed on one face 22; a paper detecting means 17 for detecting the paper 14 stored in the paper storing means 16; and a carrying switching means 18 for switching carrying operation from a direction for storing the paper 14 in the paper storing means 16 to a direction for taking out the paper 14 from the paper storing means 16, when the paper detecting means 17 detects the paper 14. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a copying machine, a facsimile machine, and a multifunction machine, and more particularly to an image forming apparatus provided with a mechanism for forming images on both sides of a sheet.

  2. Description of the Related Art Conventionally, an image forming apparatus provided with a mechanism for forming images on both sides of a sheet for the purpose of reducing the amount of paper used to form an image and saving the storage space of the sheet on which the image is formed. Has been developed.

As shown in FIG. 3, this type of image forming apparatus 1 is provided with an intermediate tray 2 inside, and the sheet 4 on which an image is formed on one side by the image forming unit 3 is The intermediate tray 2 is temporarily stacked while being held in a horizontal posture. Then, the paper 4 accumulated on the intermediate tray 2 is switched back and reversed, and then conveyed again to the image forming unit 3, and an image is formed on the other surface of the paper 4 in the image forming unit 3, and as a result. Images are formed on both sides of the paper 4 (see, for example, Patent Document 1).
JP 2000-200014 A

  However, in the conventional image forming apparatus 1 described above, it is necessary to secure a space in the image forming apparatus 1 for installing the intermediate tray 2 in which the sheets 4 are held in a horizontal posture. There was a problem that miniaturization was difficult.

  In addition, in order to reverse the paper 4 accumulated on the intermediate tray 2, it is necessary to switch back the paper 4. This switchback has a problem that the conveyance path overlaps and the conveyance control of the paper 4 becomes complicated. It was. Furthermore, there is a problem that it is difficult to increase the speed of the image forming process due to the overlap of the conveyance paths.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus capable of reducing the size of the apparatus, simplifying paper conveyance control, and speeding up image forming processing. That is what you want.

  In order to achieve the above-described object, the present invention provides an image forming apparatus having a mechanism for forming images on both sides of a sheet, the sheet feeding means for feeding the sheet, and the sheet fed by the sheet feeding means. An image forming unit that forms an image; and a reversing sheet feeding unit that reverses the sheet on which the image is formed on one side by the image forming unit and supplies the sheet to the image forming unit again. The means includes a spiral paper storage means for temporarily storing a paper having an image formed on the one surface, a paper detection means for detecting the paper stored in the paper storage means, and the paper detection means. And a conveyance switching unit that switches a conveyance operation from a direction in which the sheet is accommodated in the sheet accommodating unit to a direction in which the sheet is taken out from the sheet accommodating unit when the sheet is detected.

  The paper detection means includes a detection sensor that detects a terminal end of the paper, and the transport switching means includes a transport roller provided inside the paper storage means, and a paper entrance / exit of the paper storage means. A conveyance path switching lever provided in the portion may be provided.

  According to the present invention, when a sheet on which an image is formed on one side is reversed, the sheet is accommodated in the spiral sheet accommodating unit, so that the space for installing the reversing sheet feeding unit can be saved. Therefore, the image forming apparatus can be easily downsized.

  In addition, by changing the length of the spiral portion of the sheet storage unit, it is possible to easily reverse a sheet of an arbitrary size, so that the degree of freedom in designing the image forming apparatus can be increased.

  Further, in the reverse sheet feeding unit, since the conveyance paths do not overlap, the sheet conveyance control is simplified and the image forming process can be speeded up, thereby obtaining various excellent effects. Can do.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2. Here, FIG. 1 is a schematic diagram illustrating the configuration of the image forming apparatus according to the present embodiment, and FIG. 2 is a schematic diagram illustrating the configuration of the reverse sheet feeding unit of the image forming apparatus. In the following description, a case where the present invention is applied to a copying machine will be described as an example.

  The copying machine 11 includes a sheet feeding unit (not shown) that collects sheets in the lower part of the copying machine 11 and supplies the sheet, and a photosensitive drum 12 that forms an image on the sheet fed by the sheet feeding unit. And an inversion paper feeding unit 15 that inverts the paper 14 on which the image is formed on one side by the image forming unit 13 and supplies the paper 14 again to the image forming unit 13.

  As shown well in FIG. 2, the reversal paper feeding means 15 includes a spiral paper storage unit 16 that temporarily stores a paper 14 on which an image is formed on one side, and a paper storage unit 16 that stores the paper. Detection sensor 17 that detects the end portion 23 of the paper 14 that has been applied, and when the detection sensor 17 detects the paper 14, it conveys the paper 14 from the direction in which the paper 14 is received in the paper storage 16 to the direction in which it is removed And a conveyance switching mechanism 18 for switching the operation. The conveyance switching mechanism 18 includes a conveyance roller 19 provided inside the paper storage unit 16 and capable of rotating in the forward and reverse directions, and a conveyance path switching lever 20 provided at a paper entrance / exit portion of the paper storage unit 16. The transport path switching lever 20 is provided so as to be swingable about a support shaft 21 as a fulcrum.

  Next, the operation when images are formed on both sides of the sheet in the copying machine 11 according to the present embodiment will be described.

  As shown by the arrows in FIG. 1, the sheet supplied to the image forming unit 13 by the sheet feeding unit has an image transferred to one surface 22 by the photosensitive drum 12, and the sheet 14 on which the image is transferred is Then, the paper is conveyed to the reverse paper feeding means 15. In the reversal paper feeding means 15, the paper 14 on which the image is formed on the one surface 22 is spirally formed in the paper storage portion 16 by the forward rotation of each transport roller 19 (clockwise rotation in FIG. 2). Is housed in.

  In this way, when the paper 14 is stored in the paper storage unit 16 and the detection sensor 17 detects the end portion 23 of the paper 14, the transport path switching lever 20 swings around the support shaft 21 as indicated by a broken line in FIG. The conveyance path is switched while being held in the state, and each conveyance roller 19 rotates in the reverse direction (rotates counterclockwise in FIG. 2). As a result, the paper 14 stored in the paper storage unit 16 is taken out of the paper storage unit 16 and supplied again to the image forming unit 13.

  Thereafter, in the image forming unit 13, the image is transferred onto the other surface 24 of the paper 14 by the photosensitive drum 12, and as a result, images are formed on both surfaces of the paper. Then, the paper 14 on which images are formed on both sides is discharged to a discharge tray (not shown).

  As described above, according to the above-described embodiment, when the paper 14 having the image formed on the one surface 22 is reversed, the paper 14 is accommodated in the spiral paper accommodating portion 16. The space for installing the means 15 can be saved, and the image forming apparatus 11 can be easily downsized. Further, by changing the length of the spiral portion of the sheet storage unit 16, it becomes possible to easily reverse a sheet of an arbitrary size, so that the degree of freedom in designing the image forming apparatus 1 can be increased. Further, since the reverse feeding unit 15 switches the conveyance path when the paper 14 is reversed and the conveyance paths do not overlap, the conveyance control of the paper 14 is simplified and the image forming process is speeded up. be able to.

  In the above-described embodiment, the case where the present invention is used in the copying machine 11 has been described. However, the present invention is not limited to this case. Needless to say, the present invention can also be applied to an image forming apparatus.

1 is a schematic diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a schematic diagram illustrating a configuration of a reverse sheet feeding unit of the image forming apparatus according to the embodiment of the present invention. It is the schematic which shows the conventional image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Image forming apparatus 13 Image forming part 14 Paper 15 Reverse feed means 16 Paper storage part 17 Detection sensor 18 Conveyance switching mechanism 19 Conveyance roller 20 Conveyance path switching lever

Claims (2)

An image forming apparatus having a mechanism for forming images on both sides of a sheet,
Paper feeding means for feeding paper,
An image forming unit that forms an image on a sheet supplied by the sheet feeding unit;
A reversing sheet feeding unit that reverses the sheet on which the image is formed by the image forming unit and supplies the sheet to the image forming unit again;
With
The reversing paper feeding means includes a spiral paper containing means for temporarily containing a paper having an image formed on the one surface, a paper detecting means for detecting the paper contained in the paper containing means, An image forming apparatus, comprising: a transfer switching unit that switches a transfer operation from a direction in which the sheet is stored in the sheet storage unit to a direction in which the sheet is extracted from the sheet storage unit when the sheet detection unit detects the sheet; apparatus. The paper detection means includes a detection sensor for detecting a terminal end of the paper, and the transport switching means is provided at a transport roller provided inside the paper storage means and a paper entrance / exit portion of the paper storage means. The image forming apparatus according to claim 1, further comprising a conveyance path switching lever provided.

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