JP4177872B2 - Printing device - Google Patents

Description

  The present invention relates to a printing apparatus that simultaneously prints on both sides of a sheet.

  In this type of printing apparatus, a first printing unit is disposed on the downstream side in the paper conveyance direction in the paper conveyance path, and a second printing unit is disposed on the upstream side in the paper conveyance direction. There is one that prints on both sides of a sheet simultaneously by the second printing unit.

The first printing unit includes a first thermal head as a print head, and a first platen roller that is disposed to face the first thermal head via a paper conveyance path and conveys the paper. The The second printing unit includes a second thermal head as a print head, and a second platen roller that is disposed to face the second thermal head via a paper conveyance path and conveys the paper. (For example, refer to Patent Document 1).
US Pat. No. 6,784,906

  By the way, since the paper is stretched between the first and second printing portions and printing is started at the same time, it is between the printing start position of the first printing portion and the printing start position of the second printing portion. There is a deviation, and the second printing unit cannot print on the sheet area from the printing start position to the printing start position of the first printing unit.

  However, conventionally, since the platen roller is used as the platen of each of the first and second printing units, the distance between the printing start position of the first printing unit and the printing start position of the second printing unit. Cannot be made smaller than the diameter of the platen roller, and an area that cannot be printed by the second printing section (hereinafter referred to as an unprintable area) is increased, resulting in waste.

  Note that the distance between the print start position of the first print unit and the print start position of the second print unit can be reduced by reducing the diameter of the platen roller of the second print unit. In this case, the width of the nip portion, which is the contact portion between the platen roller and the thermal head, becomes small, and good printing cannot be expected.

  The present invention has been made by paying attention to the above circumstances, and the object of the present invention is to prevent the printing start position of the first printing unit and the second printing unit from affecting the printing performance of the second printing unit. It is an object of the present invention to provide a printing apparatus that can reduce the distance from the print start position.

To solve the above problems, those of claim 1, wherein the first print head and first platen, further the second print head and a second platen disposed opposite via the sheet conveyance path, wherein The first print head prints on one side of the paper, the second print head prints on the other side of the paper, and prints on both sides of the paper simultaneously. The first platen rotates in the platen roller for imparting a conveying force to the sheet with the second platen, the apparatus is fixed is provided to the main body, wherein a radius substantially the same radius of curvature of the first platen An arcuate surface facing the second print head, the length in the paper transport direction being smaller than the diameter of the first platen, and the second print head and the second platen Diameter of first platen By a dimension difference between the sheet conveying direction of the length dimension of the second platen, characterized in that it is arranged close to the first print head.

  According to the present invention, it is possible to reduce wastefulness by reducing the unprintable area of a sheet without impairing the printing performance.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.
FIG. 1 shows a printing apparatus according to an embodiment of the present invention.

  In the figure, reference numeral 1 denotes an apparatus main body, and a reel unit 3 for supplying paper 2 is provided in the apparatus main body 1. One side of the paper 2 is a thermal printing surface 2a, and the other side is a thermal printing surface 2b. The sheet 2 is pulled out along the sheet conveyance path 4, and the first and second printing units 6 and 7 are disposed in the sheet conveyance path 4. The first printing unit 6 is located on the downstream side in the paper conveyance direction, and the second printing unit 7 is located on the upstream side in the paper conveyance direction.

  The first printing unit 6 includes a first thermal head 10 as a first printing head, and P1 is a heating element position (printing start position). A platen roller 11 serving as a first platen is provided on the upper side of the first thermal head 10 via a paper conveyance path 4. The platen roller 11 is driven to rotate in the direction of the arrow shown by a drive mechanism (not shown).

  The second printing unit 7 includes a second thermal head 20 as a second printing head, and P2 is a heating element position (printing start position). A second platen 21 is fixedly provided on the lower side of the second thermal head 20 via the paper transport path 4.

  The dimension of the second platen 21 in the sheet conveyance direction is smaller than the diameter dimension of the platen roller 11, and the heating element position P <b> 2 of the second thermal head 20 is set to the heating element of the first thermal head 10 by the dimension difference. The second thermal head 20 and the second platen 21 can be arranged close to the position P1. The surface of the second platen 21 is covered with a low friction member and faces the second thermal head 20. The surface of the second platen 21 is an arcuate surface 21 a having a curvature radius substantially the same as the radius of the first platen 11.

  Next, the printing operation of the printing apparatus configured as described above will be described.

  First, the sheet 2 is pulled out from the reel unit 3, and the sheet 2 is stretched between the first printing unit 6 and the second printing unit 7, and the first and second thermal heads 10, 20 are combined with the first and second printing units. 2 between the two platen rollers 11 and 12.

  From this state, the platen roller 11 of the first printing unit 6 is rotationally driven by a drive mechanism (not shown) as indicated by an arrow. As a result, the paper 2 is fed in the direction of the arrow shown in the figure, and the first thermal head 10 prints information Ja on one side 2a of the paper 2 as shown in FIG. As a result, information Jb is simultaneously printed on the other side 2b of the sheet 2 as shown in FIG.

  As described above, according to this embodiment, the second platen 21 is fixedly provided, and the length dimension in the paper transport direction is made smaller than the diameter dimension of the first platen 11. The print start position P2 of the second thermal head 20 can be brought close to the print start position P1 of the first thermal head 10. Therefore, the non-printable area S that cannot be printed by the second thermal head 20 can be reduced, and waste can be reduced. Further, in the present embodiment, since the second platen 21 is fixedly provided, an appropriate resistance can be obtained when the paper 2 is fed. As a result, it is possible to give tension to the paper 2, and it is possible to prevent printing failure and jamming when the paper 2 is fed.

  Further, since the portion of the second platen 21 facing the second thermal head 20 is an arcuate surface 21a having a curvature radius substantially the same as the radius of the first platen 11, the sheet conveyance of the second platen 21 is performed. Even if the length in the direction is reduced, a sufficient nip width can be formed between the second thermal head 20 and the printing performance is not impaired.

  Further, since the surface of the second platen 21 is covered with the low friction member, there is little friction between the guide surface 21a and the paper 2 and there is no possibility of preventing the paper 2 from being conveyed.

  In the above embodiment, the surface of the second platen 21 is coated with the low friction member. However, the present invention is not limited to this, and the surface of the second platen 21 may be coated with the low friction member. The second platen 21 itself may be molded using a low friction member.

  Note that the present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above-described embodiments. For example, you may delete some components from all the components shown by embodiment mentioned above. Furthermore, you may combine the component covering different embodiment suitably.

1 is a schematic diagram illustrating a printing apparatus according to an embodiment of the present invention. The figure which shows the printing state of the both surfaces of the paper printed by the printing apparatus of FIG. FIG. 5 is a schematic diagram illustrating a printing apparatus according to a second embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 2 ... Paper, 4 ... Conveyance path, 6 ... 1st printing part, 7 ... 2nd printing part, 10 ... 1st thermal head (1st printing head), 11 ... Platen roller (1st platen) , 20 ... second thermal head (second print head), 21 ... second platen, 21a ... arc surface, 103 ... first printing section, 104 ... second printing section, 107 ... first thermal Head, 108 ... first platen roller, 111 ... second thermal head, 112 ... second platen roller

Claims (5)

The first print head and the first platen, and further, the second print head and the second platen are arranged to face each other via a paper conveyance path, and printing is performed on one surface side of the paper by the first print head, Printed on the other side of the paper by a second print head and simultaneously printed on both sides of the paper,
The first platen is a platen roller that rotates and applies a conveying force to the paper.
Said second platen device is fixed is provided to the main body, provided with an arc surface facing the first platen radius and said substantially have the same radius of curvature the second print head, wherein The length dimension in the paper transport direction is smaller than the diameter dimension of the first platen ,
The second print head and the second platen are arranged so that the first printing is performed by a dimensional difference between a diameter dimension of the first platen and a length dimension of the second platen in the paper transport direction. A printing apparatus, wherein the printing apparatus is arranged close to a head .   The printing apparatus according to claim 1, wherein at least an arc surface of the second platen is coated with a low friction member.   The printing apparatus according to claim 1, wherein the second platen is constituted by a low friction member. The second platen is located upstream of the first platen in the paper transport direction,
The printing apparatus according to claim 1, wherein the surface of the second platen has a lower friction than the surface of the first platen.   The printing apparatus according to claim 1, wherein the first and second print heads are thermal heads.

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