JP2000109275A - Perfecting press - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a perfecting press that can prevent a disorder of image on paper. SOLUTION: The perfecting press comprises a printing section 1 and a paper inverting section 2. The printing section 1 consists of a paper feed part 11 for feeding media 3 sheet by sheet, a register part 12 for timing, a photosensitive drum 13 adapted to attract toners for image elicitation, a transfer roller 14 for transferring the images on the photosensitive drum 13 to the media 3, a fixing part 15 for fixing up the toners transferred to the media 3 by pressure and heat, and a paper guide 16 for guiding the media 3 out of the fixing part 15. The paper inverting section 2 consists of a paper guide 21 for guiding the media 3 out of the printing section 1, feed rollers 22 for feeding the media 3 guided by the paper guide 21, and inversion rollers 23 for changing the feed direction of the media 3. The media feeding speed in the paper inverting section 2 is so regulated in relation to that in the printing section 1 as to keep the printed surface of the media 3 off the paper guides 16 and 21.

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 avoiding an image failure when a medium required for performing two-sided printing is reversed.

[0002]

2. Description of the Related Art Conventionally, this type of double-sided printing apparatus has been disclosed in Japanese Patent Application Laid-Open No. 7-210059, for example, when performing double-sided printing, paper guides 16 and 2 shown in FIG.
There is a concern that a printed sheet may come into contact with the sheet 1 and disturb the image on the sheet.

[0003]

A problem with the conventional double-sided printing apparatus is that there is a fear that a failure that disturbs an image on a sheet may occur. The reason is that, for example, when printing an image with a high print density, the printed paper comes into contact with the paper guide and stains the paper guide, and the stain is transferred to the paper. Further, in the case of the electrophotographic printing method, the paper guide is heated by the heat of the paper, so that the paper guide becomes dirty, and the dirt is transferred to the paper.

An object of the present invention is to provide a double-sided printing apparatus which avoids the disturbance of an image on a sheet.

[0005]

According to the present invention, there is provided a double-sided printing apparatus comprising: a paper feed unit for feeding a medium one by one; a resist unit for setting a timing; and a photosensitive drum for adhering toner for visualizing an image. A transfer roller for transferring the image of the photosensitive drum to the medium, a fixing unit for fixing the toner transferred to the medium with pressure and heat, and a guide for the medium discharged from the fixing unit. A printing unit including a paper guide, a second paper guide for guiding the medium conveyed from the printing unit, and a conveyance roller for conveying the medium guided by the second paper guide, A paper reversing unit comprising a reversing roller for changing the transport direction of the medium, wherein the medium transport speed in the paper reversing unit is set to the medium transport speed in the printing unit. Printed surface of the guide and the second sheet guide to said medium and adjusting the speed so as not to contact.

[0006] Further, the double-sided printing apparatus according to the present invention uses one medium.
A printing unit including a sheet feeding unit for feeding sheets one by one, a registration unit for setting a timing, an inkjet recording head which is a unit for printing an image on the medium, and a paper guide for guiding the medium, A second paper guide for guiding the medium conveyed from a printing unit, a conveyance roller for conveying the medium guided by the second paper guide,
A sheet reversing unit comprising a reversing roller for changing the transport direction of the medium, and a sheet reversing roller configured to change the medium transport speed in the sheet reversing unit with respect to the medium transport speed in the printing unit. The speed is adjusted so that the printing surface of the medium does not contact the guide and the second paper guide.

Further, the double-sided printing apparatus of the present invention is characterized in that the medium conveying speed in the paper reversing section is made faster than the medium conveying speed in the printing section.

Further, the double-sided printing apparatus according to the present invention is a copying apparatus.

Further, the double-sided printing apparatus according to the present invention is a facsimile apparatus.

Further, the double-sided printing apparatus of the present invention is an image forming apparatus such as a printer.

[0011]

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing an embodiment of the present invention. Referring to FIG. 1, the duplex printing apparatus according to the present embodiment has a configuration in which a paper reversing unit 2 is mounted on a printing unit 1.

The printing unit 1 is a paper feeding unit 1 for feeding the medium 3 one by one.
1, a resist unit 12 for setting a timing, and a photosensitive drum 13 to which toner is attached to make an image visible
, A transfer roller 14 for transferring the image of the photosensitive drum 13 to the medium 3, a fixing unit 15 for fixing the toner transferred to the medium 3 with pressure and heat, and a paper guide 16. In addition, a developing unit for attaching toner to the photosensitive drum and a controller for controlling the apparatus are not shown in the figure.

The paper reversing unit 2 includes a paper guide 21, a transport roller 22 for transporting the medium 3, and a reversing roller 23 for changing the transport direction of the medium 3. In addition, although there is a controller for controlling the mechanism, it is not described in the present invention because it is not necessary.

Next, the operation of this embodiment will be described with reference to FIG.

The medium 3 supplied from the paper supply unit 11 is transported between the photosensitive drum 13 and the transfer roller 14 via the registration unit 12 to transfer the toner. Further, the toner is fixed to the medium 3 by the fixing unit 15. In order to perform double-sided printing, the medium 3 is transported by the transport roller 22 through the paper guide 16 of the printing unit 1 and the paper guide 21 of the paper reversing unit 2, and the transport direction of the medium 3 is changed by the reversing roller 23. The sheet is conveyed to the resist unit 12 and turned over. At this time, by increasing the transport speed of the medium 3 to the transport roller 22 of the sheet reversing unit 2 compared to the fixing unit 15, the medium 3 can be transported without the printing surface contacting the paper guides 16 and 21. The transport speed can be changed by adjusting the roller diameter or the gear ratio of the sheet reversing unit 2.

Next, another embodiment of the present invention will be described with reference to FIG. FIG. 2 differs from FIG. 1 in the configuration of the apparatus in that a transport roller 17 is provided after the fixing unit 15. In this case, the same effect can be obtained by making the transport roller 22 of the sheet reversing unit 2 faster than the transport speed of the transport roller 17 of the printing unit 1. The transport speed is the paper reversing part
It can be changed by adjusting the roller diameter or gear ratio of 2.

In the above description, the printing unit 1 is described in the electrophotographic printing system, but it can be realized in another printing system such as an ink jet printing system.

The above-described double-sided printing apparatus can be used as a copying apparatus or a facsimile apparatus together with another optical system, or can obtain image information from a host apparatus and form an image on a printer or the like. It can be a device.

[0020]

As described above, the effect of the present invention is as follows.
This means that the quality of image quality during double-sided printing can be ensured. The reason is that the printing surface is conveyed without contacting the paper guide.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention.

FIG. 2 is a schematic view showing another embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 printing unit 2 paper reversing unit 3 medium 11 paper feeding unit 12 registration unit 13 photosensitive drum 14 transfer roller 15 fixing unit 16 paper guide 17 transport roller 21 paper guide 22 transport roller 23 reverse roller

Claims (6)

[Claims] 1. A sheet feeding unit for feeding a medium one by one, a resist unit for setting a timing, a photosensitive drum to which toner is adhered to make an image visible, and an image of the photosensitive drum transferred to the medium Transfer roller, a fixing unit for fixing the toner transferred to the medium with pressure and heat, and a printing unit including a paper guide for guiding the medium discharged from the fixing unit, A second paper guide that guides the medium conveyed from the printing unit, a conveyance roller that conveys the medium guided by the second paper guide, and a reversing roller that changes the conveyance direction of the medium. A sheet reversing unit, comprising: a medium conveying speed in the sheet reversing unit with respect to a medium conveying speed in the printing unit;
A two-sided printing apparatus, wherein the speed is adjusted so that the printing surface of the medium does not contact the paper guide. 2. A sheet feeding unit for feeding a medium one by one, a registration unit for timing, an ink jet recording head for printing an image on the medium, and a paper guide for guiding the medium. A printing unit configured, a second paper guide for guiding the medium conveyed from the printing unit, a conveyance roller for conveying the medium guided by the second paper guide, and a conveyance direction of the medium And a sheet reversing unit comprising a reversing roller for changing the medium conveying speed in the sheet reversing unit with respect to the medium conveying speed in the printing unit. A double-sided printing apparatus, wherein the speed is adjusted to such an extent that the printing surface of the medium does not contact the guide. 3. The double-sided printing apparatus according to claim 1, wherein the medium conveying speed in the sheet reversing unit is set to be higher than the medium conveying speed in the printing unit. 4. The double-sided printing apparatus according to claim 1, wherein said double-sided printing apparatus is a copying apparatus. 5. The double-sided printing apparatus according to claim 1, wherein the double-sided printing apparatus is a facsimile machine. 6. The two-sided printing apparatus according to claim 1, wherein the two-sided printing apparatus is an image forming apparatus such as a printer.