JPH0655531B2 - Printer - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a printing apparatus capable of double-sided printing.

2. Related Art and Problems Conventionally, in a printing apparatus used as an output device of a facsimile or a managing electronic device, a print head is only on one side of a print medium. It was flipped over and reinserted.
However, according to this method, automatic printing is impossible and extremely complicated operation is required.

In addition to this, there is also a method of reversing the lateral direction of the medium to perform double-sided printing, but there is a drawback that the width dimension of the apparatus becomes large.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional drawbacks, and an object of the present invention is to provide a printing apparatus capable of double-sided printing, downsized, and automated.

According to the present invention, at least a printing section and a first section from the medium inlet to the medium outlet through the printing section are provided.
Y of the first medium transport path and the first medium transport path connected to each other at two branch paths near the printing section and near the medium inlet.
It is equipped with a retreat path composed of a second medium transport path having a letter shape or a loop shape, and a medium transport roller provided in each medium transport path. A branch valve made of a flexible film or thin plate is provided, and the branch valve always closes the second medium transport path, and the medium is directed from the retreat path to the first medium transport path. When it is conveyed, the medium is pushed open to the medium so that the medium can pass through the first medium conveying path. Achieved by providing a printing device characterized in that by passing through a letter-shaped or loop-shaped retracting path, the front and back are inverted and returned to the first medium transporting path, and the printing is performed again on the back side. To be done.

Embodiments of the Invention Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 5.

As shown in FIG. 1, the present embodiment has a printing section including a print head 1 and a platen 2, and a medium transport path for supplying a medium to the printing section.

The medium transport path is a Y-shaped medium connected to a first medium transport path 3 that transports a medium from the medium inlet / outlet 4 to the printing unit, the vicinity of the medium inlet / outlet 4 of the first medium transport path 3 and the front of the printing unit. The second medium transport path 5 (which serves as a retreat path) is shaped like a triangle, and the first and second medium transport paths are connected in a substantially triangular shape.

The connecting portion between the first medium carrying path 3 and the second medium carrying path 5 connected to the vicinity of the medium entrance / exit of the first medium carrying path 3 is a first branch path 6 branched in a Y shape. Therefore, the connecting portion between the first medium conveying path 3 and the second medium conveying path 5 connected to the vicinity of the printing portion of the first medium conveying path 3 becomes a second branch passage 7 branched in a Y shape. , The Y-shaped second medium conveying path 5 has a third branch path 8 at its branch portion.
7 and 8 are branch valves 9 and 1 made of a flexible material such as polyester film or stainless steel thin plate.
0 and 11 are provided respectively.

The branch valve 9 provided in the first branch path 6 normally closes the second medium transport path 5, and when the medium 20 is transported from the medium inlet / outlet 4, the medium 20 So that the medium 20 is pushed open by the medium 20 when it is sent from the second medium conveying path 5 so that the medium 20 can pass toward the medium inlet / outlet 4. Has become.

In addition, the branch valve 10 provided in the second branch path 7 always closes the first medium carrying path 3, and the medium 20 moves the first medium carrying path 3 into the first branch path 6. When the medium 20 is sent from one side, the medium 20 is pushed open to allow the medium 20 to pass toward the printing section, and when the passing medium 20 is fed back from the printing section, the medium 20 is moved to the second side. It can be guided toward the medium transport path 5.

Further, the branch valve 11 provided in the third branch passage 8 normally closes the conveying passage of the second medium conveying passage 5 which is connected to the second branch passage 7, and the medium 20 is When the medium 20 is conveyed from the second branch path 7, the medium 20 is pushed open to allow the medium 20 to pass through, and when the medium 20 passing through the branch path 11 is fed backward, The second medium carrying path 5 can be guided toward the carrying path connected to the first branch path 6.

Further, each of the branch paths (connecting portions) 6,
In front of 7 and 8, medium transfer rollers 12 and 1 that can rotate forward and backward
3, 14 and medium detection sensors 15, 16, 17 are arranged, and further, the medium transfer roller 1 provided in the first medium conveying path 3
A medium feed motor 21 for rotating 2 and 13 forward or backward,
A reversing motor 22 for driving the medium transfer roller 14 arranged in the second medium conveying path 5 to rotate forward or backward is provided.

As shown in the control block diagram of FIG. 2, the print head 1 is connected to the head driver, the medium feeding motor 21 is connected to the medium feeding motor driver, and the reversing motor 22 is connected to the reversing motor driver. It is connected to the CPU 30 via a port. The CPU 30 is also connected with medium detection sensors 15, 16, 17 and a line buffer 31.

Next, the operation of the present embodiment having such a configuration will be described with reference to FIG.

First, as shown in FIG. A, the medium 20 inserted from the medium inlet / outlet 4 is transported through the first medium transport path 3 by the medium transport roller 12, and is guided toward the printing portion by the branch valve 9 of the first branch path 6. . Then, the medium 20 pushes open the branch valve 10 of the second branch passage 7 by the rigidity of the medium itself and advances in the direction of arrow p (that is, the direction of the printing portion) as shown in FIG. Then, the print head 1 starts printing when the front end of the medium 20 is detected by the medium detection sensor 16 and then fed in a fixed amount. When printing is completed, the medium 20 is further fed in the same direction as shown in FIG.
When the lower end of the sheet passes through the second branch path 7 and is detected by the medium detection sensor 16, the transfer operation is stopped.

Next, the medium transfer roller 13 rotates in the reverse direction to transfer the medium 20 in the direction opposite to the arrow p. At this time, the medium 20 is the second as shown in FIG.
In the branch passage 7 of the
Be guided to. Further, as shown in FIG. 8e, the medium 20 that advances along the second medium conveying path 5 is a branch valve of the third branching path 8 due to the vigor of the medium itself.
11 is pushed open to proceed, and when the trailing edge of the medium passes the medium detection sensor 17, the medium feeding by the medium feeding roller 14 is stopped.

Then, the medium transfer roller 14 is reversely rotated as shown in FIG. The medium 20 sent back is the branch valve of the third branch passage 8.
11 is guided to the first branch path 6 through the second medium carrying path, further pushes open the branch valve 9 of the branch path 6 to enter the first medium carrying path 3, and the rear end is It stops when it passes the medium detection sensor 15. In this state, the medium 20 is turned upside down.

The medium, which has been turned upside down, is again conveyed by the medium transfer roller as shown in FIG.
12 is guided by the branch valve 9 in the direction of the second branch path 7, further pushes open the branch valve 9 to pass through the second branch path 7, and is transported to the printing section by the medium transport roller 13 and is conveyed to the back side. Is printed. In this case, since the medium 20 is turned upside down from the beginning, the printing portion is passed without being printed, and the trailing edge of the medium is passed through the medium detection sensor 16 and then moved backward to print data as described later. It is printed upside down and left and right. Media 20 for which the front and back sides have been printed is the outlet 18
Or from the medium inlet / outlet 4 through the second medium transport path 5.

Next, the reverse printing of the character structure will be described. FIG. 4 is an explanatory view when characters such as'ABC 'are printed on the front surface and'Aiu' is printed on the back surface, and FIG. 5 is a line buffer 31.
It is a character pattern memory | storage state figure in (refer FIG. 2).

As shown in FIG. 4, the medium on which "ABC" is printed on the surface is discharged in the direction of arrow A, and the characters to be printed are also read from the line buffer in the normal order and printed. on the other hand,
When the reverse side printing is started, the medium is inverted upside down, so the medium is not sucked in the direction of arrow A ', and further, the reading of the character pattern from the line buffer is printed upside down. .

FIG. 6 is a diagram showing a main part of another embodiment of the present invention.

In the present embodiment, a first medium conveying path 80 from the medium inlet / outlet 4 to the medium discharging port 18 through the printing section composed of the printing section 1 and the platen 2, and the printing section of the first medium conveying path 80. A second medium transport path (serving as a retreat path) 81 that branches from a vicinity and goes around the half circumference of the platen 2 and connects again to the vicinity of the medium inlet / outlet 4 of the first medium transport path 80 is provided near the printing section. A separator 51 is provided at the branch portion of which a medium transport direction can be selected to the direction of the medium discharge port 18 or the direction of the second medium transport path 81,
A branch valve 50 formed of a flexible material, such as a polyester film or a stainless steel thin plate, is provided at the connection portion of the first and second medium transport paths near the medium inlet / outlet 4.

The branch valve 50 normally closes the second medium carrying path 81, and when the medium is sent from the second medium carrying path 81, the branch valve 50 pushes the medium to open it. 1 medium transport path 80
It is possible to pass it to. In the figure, 40 is a pinch roller in contact with the platen, 4
Reference numerals 1 and 42 are a pinch roller and a feed roller provided in the first medium carrying path 80.

In the present embodiment configured as described above, first, the separator 51 is positioned so that the medium is guided toward the second medium transport path 81. Then, from the medium entrance / exit 4 to the first medium conveyance path
While supplying the medium to 80 and printing in the printing section
The medium is conveyed to the medium conveying path 81. The medium conveyed through the second medium conveyance path 81 pushes the branch valve 50 open by the rigidity of the medium itself, enters the first medium conveyance path 80, and is conveyed toward the medium entrance / exit 4. The conveyance of the medium is stopped when the rear end of the medium passes the branch valve 50. At this point the medium is inside out.
In order to print on a medium that has been turned inside out, the top and bottom of the medium are upside down, so let the print section pass once without printing, and then move backward when the trailing edge of the medium passes the print section. Print from the top of the. The medium for which printing has been completed is discharged from the medium inlet / outlet 4, or the separator 51 is tilted to the platen side and discharged from the medium outlet 18.

In this way, in this way, both the front and back sides can be printed in the same manner as in the previous embodiment. Further, there is an advantage that the printing apparatus can be downsized when the size of the medium in the traveling direction does not exceed the length of the second medium transport path 81.

EFFECTS OF THE INVENTION As described above in detail, the printing apparatus of the present invention has a simple structure including a second medium transport path (retraction path) that reverses the front and back of a medium and a branch valve that automatically opens and closes by the medium. As a result, double-sided printing becomes possible, and miniaturization and automation can be easily realized, which is a great effect.

[Brief description of drawings]

1 and 2 are views for explaining a printing apparatus according to the present invention, FIG. 3 is a view for explaining the principle of the medium running operation, and FIG. 4 is for explaining character reversal when printing on the front and back sides. FIG. 5 is a storage state diagram in the line buffer, FIG.
The figure shows another embodiment of the present invention. In the drawings, 1 is a print head, 2 is a platen, and 3,80.
Is a first medium carrying path, 4 is a medium entrance / exit, 5, 81 is a second medium carrying path (retract path), 6 is a first branch path, 7 is a second branch path, and 8 is a third path. Branch path, 9, 10, 11, 50 are branch valves,
Reference numerals 12, 13, 14 denote medium transfer rollers, 15, 16, 17 denote medium detection sensors, 18 denotes a medium discharge port, and 51 denotes a separator.

Claims (1)

[Claims] 1. A print medium, a first medium conveying path extending from a medium inlet to the medium outlet through the printing unit, and the first medium conveying path.
Provided in each medium transport path, and a retreat path formed by a Y-shaped or loop-shaped second medium transport path connected to two branch paths provided in the vicinity of the print section and the medium entrance of the medium transport path A branch valve made of a flexible film or a thin plate is provided in the branch passage provided in the vicinity of the medium inlet, and the branch valve is always When the medium transport path 2 is closed and the medium is transported from the retract path toward the first medium transport path, the medium is pushed open to the first medium transport path. When the medium printed on the front side of the printing unit passes through the Y-shaped or loop-shaped retreat path, the front and back sides are reversed to the first medium conveyance path. Printing that is returned and printed on the back side again at the printing unit Location.