JPH1058772A - Paper conveying device for printer, and printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent fouling of a paper by the contact of the tip thereof with a printing head when fed by a feeding means upstream of the printing head to the downstream side. SOLUTION: A platen 50 is inclined such that the conveying roller side is farther from a printing head with respect to the standard plane linking a conveying roller 30 and a discharging roller 40. When a paper is fed to the downstream side only by the conveying roller 30, the paper is guided by the inclined face such that the paper tip gradually comes closer to the standard plane from a position away from the printing head 25 so as to be introduced to the discharging roller 40. Since the paper tip is free when being guided by the inclined face, the paper can be fed without contacting with the printing head 25 even if it is deflected or curved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper transport device and a printer for a printer, and more particularly, to a printer in which a shape of a platen is improved so that a leading end of a paper does not contact a print head.

[0002]

2. Description of the Related Art Heretofore, as a paper transport device mounted on various printers such as an ink jet printer, a transport roller for transporting a paper upstream of a print head in a paper transport direction, and a downstream of a print head in a paper transport direction. There is a printer having a discharge roller for feeding a sheet on the side, and a platen provided opposite to the print head between the transport roller and the discharge roller.

In this type of paper transport apparatus, first, the paper is sent downstream only by the transport roller, and when the leading edge of the paper reaches the discharge roller, the transport roller and the discharge roller cause the transport section of the transport roller and the discharge roller to move. The paper is sent downstream along a reference plane connecting the transport units. When the paper is sent downstream only by the transport roller, the leading edge of the paper is guided to the discharge roller by the platen.During this time, high-precision printing by the print head can be performed. The platen is provided at a position close to the print head along the reference plane so as to be guided along the reference plane.

Further, in the paper transport apparatus, when the paper is transported downstream only by the transport roller by changing the position of the transport roller and the paper feeding direction from the transport roller, the leading end of the paper is moved by the platen to the reference surface. There are various types of devices that are configured to reliably guide along the line. For example, there is also a configuration in which a sheet feeding direction from a conveying roller is set so as to intersect the reference surface at a predetermined angle, and the leading end of the sheet is brought into contact with a platen to reliably guide the sheet to the reference surface.

[0005]

However, in the above-mentioned paper transport device and a printer equipped with the paper transport device,
When the sheet is conveyed to the downstream side only by the conveying roller, the leading end of the sheet is free and easily bends or bends. That is, as described above, since the platen of the paper transport device is provided at a position close to the print head along the reference plane, even if the leading edge of the paper is slightly bent or bent, the leading edge of the paper is printed. There is a possibility that the paper may be soiled by contact with the head.

Further, in the case where the paper feed direction from the transport roller is set so as to intersect the platen at a predetermined angle, when the paper is transported downstream only by the transport roller, the leading end of the paper is free and the paper is also bent. It is easy to bend and bend, and as described above, the leading end of the paper may come into contact with the print head and the paper may be stained. In particular, if the print head is of an ink jet type that prints by ejecting ink droplets onto paper, the print head is wet with ink. It will surely get dirty.

SUMMARY OF THE INVENTION It is an object of the present invention to reliably prevent the leading edge of a sheet from coming into contact with a print head and prevent the leading edge of a sheet from being stained by contact with a print head in a paper transport device and a printer of a printer. It is.

According to a first aspect of the present invention, there is provided a paper transport apparatus for a printer, comprising: a transport roller for transporting a paper upstream of a print head in a paper transport path; and a discharge roller for transporting a paper downstream of the print head in a paper transport path. And a platen provided between the conveying roller and the discharge roller to face the printhead, and a platen having an upper surface side forming a sheet conveying path. The upstream side portion is characterized in that it is formed on an inclined portion that is inclined so as to be more distant from the print head toward the transport roller side with respect to a reference plane connecting the transport portion of the transport roller and the transport portion of the discharge roller. is there.

The paper is sent downstream only by the transport rollers,
When the leading end of the sheet reaches the discharge roller, the sheet is sent downstream along the reference plane by the transport roller and the discharge roller. When the paper is sent to the downstream side only by the transport roller, the leading end of the paper is easy to bend or bend because it is free.However, the upstream portion including the portion of the platen facing the print head is With respect to the reference surface that connects the transport section of the discharge roller, the slope is formed so as to be more distant from the print head toward the transport roller. It is guided to the discharge roller without contact. Therefore, it is possible to reliably prevent the leading edge of the paper from being in contact with the print head and becoming dirty.

According to a second aspect of the present invention, in the printer of the first aspect, the inclined portion guides the leading edge of the paper fed by the transport roller and gradually introduces the paper to the reference surface. It is formed in a shape. That is, the same effect as that of the first aspect is obtained, but since the leading end of the sheet fed by the transport roller is guided by the inclined portion and is gradually introduced to the reference plane, the leading end of the sheet is extremely discharged to the discharge roller. It is possible to smoothly guide and send.

According to a third aspect of the present invention, there is provided a printer comprising the sheet transport device of the first or second aspect of the invention and an ink jet print head for ejecting ink droplets onto a sheet for printing. . That is, since the paper transport device is configured to reliably guide the leading edge of the paper to the discharge roller without contacting the print head with the print head, the ink of the print head adheres to the paper in a printer having an inkjet print head. Can be reliably prevented.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. This embodiment is an example in the case where the present invention is applied to an ink jet printer and a paper transport device provided with the ink jet printer.

As shown in FIG. 1, an ink-jet printer 1 (hereinafter referred to as a printer) includes a paper feed cassette 10.
The sheet P fed from the insertion port 15 formed in the upper part of the frame main body 2 by the sheet feeding device 3, the sheet feeding device 3, or the hand that feeds the plurality of sheets P set one by one. A paper transport device 5 for feeding the print head 25 and transporting it to the discharge stacker 7, a printing mechanism 4 for printing on the paper P transported by the paper transport device 5, and the like are provided.

The paper feeding device 3 includes a paper feeding cassette 10 capable of stacking and setting a plurality of sheets of paper P, a paper feeding roller 14 mounted on a rotating shaft 14a supported by the frame main body 2, and a rotating roller (not shown). The paper feed roller 1 is rotatably mounted on the shaft 14a and is made of a color or the like that maintains the interval between the sheet P and the paper feed roller 14 at a predetermined interval.
When the paper feed roller 4 rotates, the paper feed roller 14 comes into frictional contact with the upper surface of the paper P set in the paper feed cassette 10 and rotates.
The sheets P are sent out one by one.

The paper feed cassette 10 includes a cassette main body 11 having a storage portion 11a and a paper P which can be stored in the storage portion 11a.
And a spring 13 for urging the paper feed table 12 toward the paper feed roller 14. That is, the urging force of the spring 13 causes the paper P on the paper feed table 12 to come into contact with the color, and the space between the paper P and the paper feed roller 14 is maintained at the predetermined distance.

The printing mechanism 4 includes a carriage 22 guided by a guide rod 20 and a guide rail 21 so as to be movable in the left and right directions, a holder 23 fixed to the carriage 22, and a printing attached to the rear end of the holder 23. A head 25 and an ink cartridge 24 detachably mounted on the holder 23 and supplying ink to the print head 25;
And a carriage driving mechanism (not shown) for driving the carriage 22 to move in the left-right direction. The print head 25 is of an ink jet type that prints by ejecting ink toward the paper P.

The paper transport device 5 will be described. Figure 1,
As shown in FIG. 2, the paper transport device 5 includes a paper feed device 3 or a transport roller 30 that feeds a paper P fed from the insertion opening 15 to the print head 25 side by hand, and a paper printed by the printing mechanism 30. A discharge roller 40 for discharging P to the discharge stacker 7 side; a platen 50 provided between the transport roller 30 and the discharge roller 40 so as to face the print head 25;
The upper surface side portion of the platen 50 is
Forms a paper transport path through which the paper is transported.

As shown in FIG. 2, the transport roller 30 has a feed roller 31 and a shaft 3 above the feed roller 31.
8 comprises a pressure roller 32 rotatably provided at the tip of an arm 33 which is swingably provided. The pressure roller 32 is connected to the arm 33 by a spring 34.
, The contact portion between the feed roller 31 and the pressure roller 32 forms a transport portion 35 that can pinch the paper P and transport the paper P to the downstream side. The feed roller 31 is formed to have a larger diameter than the pressure roller 32 so that the amount of sheet feeding by the transport roller 30 can be controlled with high accuracy.

Here, the sheet P fed from the sheet feeding device 3
Is forwarded obliquely upward and forward by a separating inclined surface 39 (see FIG. 1), and is guided by a guide portion 37 formed at a rear end portion of the arm 33 to transport the transport roller 30. It is guided to the unit 35. Further, the leading end of the paper P fed downward by hand from the insertion opening 15 is guided by the guide surface 36 continuing from the separation inclined surface 39,
The sheet is guided to the transfer section 35 of the transfer roller 30.

On the other hand, the discharge roller 40 is composed of a discharge drive roller 41 made of high friction rubber, and a spur 42 having a sharp projection on its outer periphery which abuts so as to be driven by the discharge drive roller 41.
And the contact portion between the discharge drive roller 41 and the spur 42 is
The transport unit 45 is a transport unit 45 capable of nipping and transporting the sheet P to the downstream side. In the discharge roller 40, since the paper P immediately after printing by the printing mechanism 4 must be conveyed, a spur 42 having a sharp projection is applied so that the ink printed on the paper P does not adhere. .

Although not shown, the feed roller 3
1 and the discharge drive roller 45 are driven to rotate by a drive mechanism having a stepping motor, a gear mechanism, and the like. The paper feed amount by the transport roller 30 is set to be slightly smaller than the paper feed amount by the discharge roller 40. . That is, while the paper P is being transported downstream by both the transport roller 30 and the discharge roller 40, the paper P
The paper P is conveyed in a taut state by slipping the paper P at the conveyance section 45 of No. 0.

As shown in FIG. 2, a platen 50 provided opposite the print head 25 between the transport roller 30 and the discharge roller 40 connects the transport section 35 of the transport roller 30 and the transport section 45 of the discharge roller 40. It has a reference surface portion 51 along a reference surface 60 (indicated by a two-dot chain line), and an inclined portion 52 inclined so as to be more distant from the print head 25 toward the transport roller 30 with respect to the reference surface 60. The inclined portion 52
Is formed in a gently inclined shape so that the leading end of the sheet P fed by the transport roller 30 is guided and gradually introduced into the reference surface 60 in an upstream portion including a portion facing the print head 25 of the platen 50. The inclination direction is substantially toward the axis of the feed roller 31.

Here, the tangent plane of the contact portion 35 of the transport roller 30 is inclined with respect to the reference surface 60 so as to be more distant from the reference surface 60 toward the discharge roller 40, and intersects with the inclined portion 52 of the platen 50. Is set. That is, the transport roller 30 feeds the sheet not parallel to the print head 25 but toward the inclined surface 52. As shown in FIGS. 3 and 4, the upper surface of the platen 50 has a plurality of peaks 55 and valleys 5.
6 are formed in a corrugated shape, and the print head 25
When the ink is ejected and adhered to the paper P from the paper P, the ink expands the paper P to form wrinkles. However, the wrinkles of the paper P are not bent toward the print head, and the platen 50 formed in a corrugated shape. The paper P can be smoothly conveyed downstream even after printing. The platen 50 is attached to the upper ends of a pair of upright walls 2a that are erected inside the main body frame 2.

The operation of the sheet transport device 5 will be described.
As described above, the paper P fed from the insertion opening 15 by the paper feeding device 3 or the hand is first sent to the print head 25 side only by the transport roller 30, and the leading end of the paper is
When the sheet reaches the transfer section 45 of 0, the sheet is sent downstream along the reference surface 60 by the transfer roller 30 and the discharge roller 40.

When the paper P is sent downstream only by the transport roller 30, the leading end of the paper is free and easily bent or bent, but the upstream end of the platen 50 including the portion facing the print head 25 is free. Since the side portion is formed as an inclined portion 52 inclined so as to be more distant from the print head 25 toward the transport roller 30 with respect to the reference surface 60, even if the leading end of the paper is bent or bent, the leading end of the paper is The guide roller 25 is guided to the transport section 45 of the discharge roller 40 without contacting the discharge roller 25.
Accordingly, it is possible to reliably prevent the paper tip from coming into contact with the print head 25 and adhering ink, and the paper from being stained.

Further, the inclined portion 52 is provided with the conveying roller 30.
The leading edge of the sheet P is guided in a gentle slope so as to guide the leading edge of the sheet P and gradually introduce the leading edge to the reference surface. Can be. In particular, in the ink jet type printer 1, when the paper P comes into contact with the print head 25, the paper P is surely stained with the ink of the print head 25. This makes it possible to reliably prevent the paper P from being stained with the ink by coming into contact with the print head 25.

[0027]

According to the first aspect of the present invention, the upstream portion including the portion of the platen facing the print head is moved with respect to the reference plane connecting the transport portion of the transport roller and the transport portion of the discharge roller. Since the paper is formed on an inclined portion that is inclined so as to move away from the print head toward the transport roller side, when the paper is sent downstream only by the transport roller, the paper is bent or bent because the leading end of the paper is free. Also, contact with the print head can be prevented, and the paper can be reliably prevented from being stained by the print head.

According to the paper transport device of the printer of the second aspect, the same effect as that of the first aspect is obtained, but the inclined portion has
It is formed so as to be gently inclined so that the leading edge of the paper fed by the transport roller is guided and gradually introduced to the reference plane from a position distant from the print head, so the leading edge of the paper is very smoothly toward the discharge roller. Can guide and send.

According to the printer of the third aspect, the paper transport device of the printer according to the first or second aspect and the ink jet print head for ejecting ink droplets onto the paper for printing are provided. This makes it possible to reliably prevent the paper from being stained with the ink of the print head upon contact with the head.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view of a printer including a paper conveying device according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a paper transport mechanism.

FIG. 3 is a plan view of a platen.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ink-jet printer 5 Paper transport device 25 Print head 30 Transport roller 35, 45 Transport unit 40 Discharge roller 50 Platen 51 Reference surface 52 Slope 60 Reference surface

Claims (3)

[Claims] A transport roller that transports the paper upstream of the print head in the paper transport path; a discharge roller that transports the paper downstream of the print head in the paper transport path; In a paper transport apparatus for a printer, provided with a print head and opposed to the print head, and a platen having an upper surface side forming a paper transport path, an upstream portion including a portion of the platen facing the print head includes a transport roller. A paper transport device for a printer, wherein the transport roller is formed on an inclined portion so as to be more distant from a print head toward a transport roller than a reference surface connecting the transport portion and a transport portion of a discharge roller. 2. The apparatus according to claim 1, wherein the inclined portion is formed to have a gentle inclination so as to guide the leading end of the sheet fed by the conveyance roller and gradually introduce the leading end to the reference surface. Paper transport device for printer. 3. The printer according to claim 1, further comprising: a paper transport device for the printer according to claim 1; and an ink jet print head that ejects ink droplets onto paper to perform printing.