JPH11310351A - Recording medium transport device - Google Patents

Abstract

(57) [Problem] To prevent skew of a recording medium even when a thick recording medium having a small width is conveyed. A pressure roller (12, 13) is uniformly pressed against a conveying roller (10, 11) by a plurality of first pressure springs, and a recording medium having a small width and a thickness equal to or greater than a predetermined thickness is formed. The transport rollers 10, 11 and the pressure rollers 12, 1 are positioned by a reference surface provided on one side of the transport path.
3, the pressure rollers 12, 13
By the pressure of the second pressure spring 18 so as to be kept parallel to the transport rollers 10 and 11. Thus, even when a thick recording medium having a small width is conveyed, skew of the recording medium is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
The present invention relates to a recording medium transport device that transports a plurality of types of recording media such as booklets.

[0002]

2. Description of the Related Art Conventionally, there is a printer that prints information on a plurality of types of recording media such as a single form, a multiple form, and a booklet. In such a printer, it is necessary to print in the process of transporting the recording medium without bending, and therefore, a recording medium in which a transport roller and a pressure roller are opposed to each other with a recording medium transport path provided along a substantially flat surface therebetween. A medium transport device is used. in this case,
The transport roller is rotatably provided at a fixed position, and the pressure roller is pressed against the transport roller by a pressure spring and is provided so as to be able to contact and separate from the transport roller. Therefore, a plurality of types of recording media can be transported by retracting the pressure roller from the transport roller according to the thickness of the recording medium.

[0003] Further, since the recording medium is different not only in thickness but also in width, in order to match the printing position, the center of the recording medium is referred to as the center reference, or the center of the recording medium transport path, or the one side reference. One side of the recording medium is referred to as a reference surface provided on one side of the recording medium transport path.

[0004]

When one side of the recording medium having a small width is aligned with the reference surface, the pressure roller urged by the pressure spring is pressed against the recording medium on the reference surface side. Since the portion opposite to the surface is directly pressed against the transport roller, the pressure roller is inclined with respect to the transport roller supported at a fixed position. This inclination increases as the thickness of the recording medium increases, such as booklets. As a result, the pressure of the recording medium received from the pressure roller changes greatly depending on the position in the width direction, and the recording medium is skewed during conveyance.

In order to prevent such a situation, a plurality of pressure rollers are independently supported along the width direction of the recording medium so as to be capable of coming into contact with and separating from the transport roller, and are biased toward the transport roller. There is a recording medium transport device provided by
A structure for independently supporting a large number of pressure rollers has a problem that the number of parts increases, which complicates the apparatus and increases the cost.

The present invention does not employ a complicated structure for independently supporting a plurality of pressure rollers along the width direction of the recording medium, and does not obliquely move a plurality of types of recording media having different width sizes. It is an object of the present invention to provide a recording medium conveying device capable of conveying.

[0007]

According to the first aspect of the present invention,
A recording medium transport path having a reference surface for guiding one side of the recording medium and passing through the printing unit; and a transport for transporting the recording medium along the recording medium transport path with the center of the rotating shaft supported at a fixed position. A roller, a pressure roller supported so as to be able to contact and separate from and rotate with respect to the transport roller, and a pressure roller disposed at a plurality of locations along the axial direction of the pressure roller to press the pressure roller against the transport roller. A plurality of first pressure springs, at least when the recording medium having a thickness equal to or greater than a predetermined thickness and positioned by the reference surface is inserted between the transport roller and the pressure roller. A second pressure unit configured to press an end of the pressure roller disposed on the upstream side of the printing unit on the reference surface side toward the transport roller with a pressing force stronger than a pressing force of the first pressing spring; And a pressure spring.

Accordingly, since the pressure roller is pressed by the first pressure spring at a plurality of positions in the axial direction, each part is uniformly pressed against the transport roller. When a recording medium having a small width size and a thickness equal to or greater than a predetermined thickness is positioned by the reference surface and inserted between the conveyance roller and the pressure roller, the recording medium is positioned at least on the upstream side of the printing unit. The pressure roller is pressed by the second pressure spring and is kept parallel to the transport roller.

According to a second aspect of the present invention, in the first aspect, the second pressure spring is provided between the plurality of pressure rollers disposed upstream and downstream of the printing unit. It is erected.

Therefore, when a recording medium having a small width and a thickness equal to or larger than a predetermined thickness is positioned by the reference surface and inserted between the transport roller and the pressure roller, the recording medium is located between the upstream side of the printing unit and The pressure roller disposed on the downstream side is uniformly pressed by one second pressure spring and is maintained parallel to the transport roller.

According to a third aspect of the present invention, in the first or second aspect of the present invention, a pressure adjusting means for adjusting the pressure of the second pressure spring is provided.

Therefore, it is possible to adjust the pressing force of the second pressing spring according to the type of the recording medium.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. First, an outline of the printer will be described with reference to FIG. In the figure, reference numeral 1 denotes a printing unit.
Is a dot printer head 3 on which a carrier 2 is mounted,
It is formed by a flat platen 4 facing the dot printer head 3. The carrier 2 is movably supported by a carrier shaft 5 and is configured to be reciprocally driven by a driving unit (not shown).

Next, the recording medium transport device 6 provided in the printer will be described. A recording medium transport path 7 that passes through the printing unit 1 is formed by a guide plate 8 and guide plates 9 that are opposed to both ends of the guide plate 8 at predetermined intervals. On the upstream side and the downstream side of the printing unit 1 in the recording medium transport path 7, transport rollers 10, 11 and pressure rollers 12, 13 arranged opposite to the transport rollers 10, 11 are disposed. I have. In this example, the transport rollers 10 and 11 and the pressure rollers 12 and 13 are provided at one location on the upstream side and the downstream side with the printing unit 1 interposed therebetween, but may be provided at a plurality of locations. Further, the recording medium transport device 6 includes a tractor 14 that is driven when printing on continuous paper as recording paper, and a movable guide plate that makes the transport path of the continuous paper parallel to the guide plate 8 when using the tractor 14. 15 is provided between the transport roller 11 and the tractor 14.
The pressure rollers 12 and 13 are transported by the first pressure spring 16 supported by the guide plate 9 to the transport roller 1.
It is pressurized to the 0, 11 side.

FIG. 2 shows a state in which the recording medium S is inserted between the conveying rollers 10 and 11 and the pressing rollers 12 and 13. The conveying rollers 10 and 11 are driven by a motor (see FIG. (Not shown), rotating shafts 10a and 11a,
It comprises a plurality of roller members 10b, 11b fixed to the respective rotating shafts 10a, 11a at predetermined intervals. Both ends of the rotating shafts 10a and 11a are rotatably supported by bearings (not shown) fixed at fixed positions. The pressure rollers 12, 13 include shafts 12a, 13a, and a plurality of roller members 12b, 13b supported on the respective shafts 12a, 13a at a predetermined interval. Both ends of the shafts 12a and 13a are supported by bearings (not shown) fixed at fixed positions.
The pressure rollers 12 and 13 are formed in an elliptical shape so as to contact and separate from the roller 1.

As shown in FIG. 3, a first pressure spring 16 is provided for each roller member 12b, 13b. Although not shown, the side plate 17 supporting the left edges of the guide plates 8 and 9 has a function as a reference surface for guiding the position of the left edge of the recording medium. A second pressure spring (leaf spring) 18 having both ends mounted on the shafts 12a, 13a of the pressure rollers 12, 13 is provided. Further, the second pressure spring 1
A pressing force adjusting means 19 for supporting the pressing force of No. 8 to be higher than the pressing force of the first pressing spring 16 and adjusting the pressing force is provided.

As shown in FIG. 4, the pressing force adjusting means 19 includes an adjusting lever 21 rotatably supported on the side plate 17 via a support shaft 20, and a plurality of rotating positions of the adjusting lever 21. And a locking member 22 fixed in a stage. A boss 23 that swingably supports a bent piece 18 a formed at the center of the second pressure spring 18 is provided on the adjustment lever 21.
And a plurality (three in this example) of locking recesses 25 that resiliently lock to the elastic locking pieces 24 formed on the locking member 22. These locking recesses 25 are arranged on a radius centered on the support shaft 20. In FIG. 3, 2
6 is screwed to the boss 23 and the bent piece 18a from the boss 23
It is a screw that prevents falling off.

In this embodiment, in FIG.
A description will be given on the assumption that printing is performed by the dot printer head 3 while a recording medium is inserted from the direction and the recording medium is transported in the direction of arrow A by the transport rollers 10 and 11 and the pressure rollers 12 and 13. When the recording medium is continuous paper, the tractor 14 also conveys the recording medium. In the case where the recording medium is a booklet, the description will be made on the assumption that the transport rollers 10 and 11 are reversed to return the printed recording medium in the direction of arrow B. However, the present invention is not limited to such a usage form. Absent.

When the recording medium is conveyed in the direction of arrow A, reference numeral 12 denotes a pressure roller disposed at a position upstream of the printing unit 1, and reference numeral 13 denotes a pressure roller disposed downstream of the printing unit 1. Pressure roller. This relationship is reversed in the case of a use mode in which printing is performed in the process of transporting the recording medium in the direction of arrow B.

When there is no recording medium, the pressure roller 1
Each of the roller members 12 and 13 is pressed by the first pressing spring 16 at a plurality of positions in the axial direction.
b, 13b are uniformly pressed against the roller members 10b, 11b of the transport rollers 10, 11.

In the case of printing on a thin recording medium such as a cut sheet, and in the case of printing on a recording medium having a large width,
The adjustment lever 21 is tilted forward (in the direction of arrow F in FIG. 4). In this case, the adjusting lever 21 is positioned at the leftmost locking recess 25.
Are fixed at positions where they are engaged with the elastic engagement pieces 24. In this state, since the position of the boss 23 of the adjustment lever 21 is raised, the second pressure spring 18 does not bend and one end only contacts one of the shafts 12a or 13a of the pressure roller 12 or 13. That is, the pressing rollers 12 and 13 transport the recording medium only by the first pressing spring 16.
Pressure contact with 0,11. In the case of a thin recording medium such as a cut sheet, the inclination of the pressure rollers 12 and 13 with respect to the transport rollers 10 and 11 is very small even if the recording medium is brought closer to the reference surface (side plate 17) because of its small width. There is no skew.

However, the thickness is a predetermined thickness (approximately 1.5 mm) such as a multiple slip or a booklet in which one side of a plurality of sheets of paper is closed.
In the case of a recording medium that is thicker and has a smaller width, if the left edge of the recording medium is positioned by the side plate 17, the inclination of the pressure rollers 12, 13 with respect to the transport rollers 10, 11 becomes large as shown in FIG. Therefore, the second pressure spring 1
8, the pressure of the shafts 12 of the pressure rollers 12, 13 is increased.
a, 13a are pressed against the conveying rollers 10, 11 side.

The strength of the pressing force varies depending on the thickness of the recording medium. That is, in the case of a multiple slip, as shown in FIG. 4, the adjustment lever 21 is moved to the center, and the center engagement recess 25 is engaged with the elastic engagement piece 24 to fix the adjustment lever 21. In this state, the position of the boss 23 is lower than when the adjustment lever 21 is tilted to the end of the side plate 17, and the second pressure spring 18 has both ends of the shafts 12 of the pressure rollers 12, 13.
a, 13a is curved in a direction in which the center portion is lowered while being supported by the left ends, and presses the pressure rollers 12, 13 to the transport rollers 10,
Pressurize to 11 side. Thereby, the pressure rollers 12, 13
Is not inclined with respect to the transport rollers 10 and 11 as shown in FIG.

In the case of booklets thicker and smaller in width than the multiple slips, the adjusting lever 2 is used to further increase the pressing force.
1 is tilted rearward (in the direction of arrow R in FIG. 4), and the locking recess 25 at the right end is locked to the elastic locking piece 24 to adjust the adjustment lever 2.
Fix 1 In this state, since the position of the boss 23 is lowest, the second pressure spring 18 is greatly bent, and the pressing force on the pressure rollers 12 and 13 is increased.

As described above, even when a recording medium having a small width and a large thickness is conveyed to one side, the pressing rollers 12 and 13 are pressed against the conveying rollers 10 and 11 by the pressing force of the second pressing spring 18. Since the recording medium can be kept parallel, skewing of the recording medium can be prevented. In this case, since the inclination of the pressure roller 12 on the upstream side of the printing unit 1 can be prevented, the sheet can be immediately fed to the printing unit 1 while the skew is prevented. Thereby, printing can be performed at an accurate printing position. When a plurality of sets of transport rollers and pressure rollers are arranged on the upstream side of the printing unit 1, at least the inclination of the pressure roller closest to the printing unit 1 is prevented by the second pressure spring 18. You may. Further, the inclination of the pressure roller 13 located on the downstream side of the printing unit 1 can be prevented, so that the recording medium immediately after printing can be discharged to a desired discharge tray or the like without skew. it can. Further, according to the present embodiment, the two pressure rollers 12, 13 disposed on the upstream side and the downstream side of the printing unit 1 can be pressed by one second pressure spring 18, so that both of them can be pressed. Can be applied to the shafts 12a, 13a of the pressure rollers 12, 13 with a uniform pressing force, and the number of parts can be reduced.

Further, a recording medium having a small surface size, such as a label mount, having a slippery surface is used as a reference surface (side plate 1).
When the recording medium is conveyed to the position 7), the pressure of the second pressure spring 18 can be increased to convey the recording medium with a high conveying force.

As described above, the second pressure spring 18
However, the recording medium having a thickness at least as large as causing skew is transported by the transport rollers 10 and 11.
The bending piece 18a of the second pressing spring 18 is located at a position where the pressing roller 12, 13 is bent so as to press the conveying roller 10, 11 when inserted between the pressing roller 12 and the pressing roller 12, 13. May be fixed to a fixing member such as the side plate 17. Further, even when the pressing force of the second pressure spring 18 is adjusted, the adjustment may be performed by using a driving force of an actuator that operates by energization without manual operation.

[0028]

According to the first aspect of the present invention, there is provided a recording medium conveying path having a reference surface for positioning one side of a recording medium, a conveying roller for conveying the recording medium with the center of the rotating shaft supported at a fixed position. A pressure roller that can be moved toward and away from the transport roller is disposed, and a first pressure spring that presses the pressure roller toward the transport roller is disposed at a plurality of locations along the axial direction of the pressure roller. When the recording medium having a thickness equal to or greater than a predetermined thickness and positioned by the reference surface is inserted between a conveyance roller and a pressure roller, the recording medium is disposed at least at a position upstream of a printing unit. Since the second pressing spring is provided to press the end of the pressing roller on the reference surface side toward the conveying roller with a pressing force stronger than the pressing force of the first pressing spring, the pressing roller is provided at a plurality of locations. Each part is pressurized by the first pressure spring. First, it can be pressed against the conveyance roller, and when a recording medium having a small width and a thickness equal to or more than a predetermined thickness is positioned by the reference surface and inserted between the conveyance roller and the pressure roller, The pressing roller is pressed by the pressing force of the second pressing spring and can be kept parallel to the transport roller. Therefore, even when a thick recording medium having a small width is conveyed, skew of the recording medium can be prevented. In this case, since the inclination of the pressure roller at least on the upstream side of the printing unit can be prevented, the sheet can be immediately fed to the printing unit while the skew is prevented. Thereby, printing can be performed at an accurate printing position.

According to a second aspect of the present invention, in the first aspect, the second pressure spring is provided between the plurality of pressure rollers disposed upstream and downstream of the printing unit. When the recording medium having a small width and a thickness equal to or greater than a predetermined thickness is positioned by the reference surface and inserted between the transport roller and the pressure roller, the upstream side of the printing unit is provided. The pressure rollers disposed on the downstream side and the downstream side can be uniformly pressed by the pressing force of one second pressure spring to be kept parallel to the transport roller. The number of the second pressure springs can be reduced, and the structure can be simplified.

According to a third aspect of the present invention, in the first or second aspect of the present invention, a pressure adjusting means for adjusting the pressure of the second pressure spring is provided. The pressing force of the second pressure spring can be adjusted, whereby skew can be more effectively prevented even if the types of recording media increase.

[Brief description of the drawings]

FIG. 1 is a side view schematically showing a printer according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a state in which a recording medium is inserted between a conveyance roller and a pressure roller as viewed from the front.

FIG. 3 is an exploded perspective view showing a relationship between first and second pressure springs.

FIG. 4 is a side view showing a relationship between a pressure roller and a second pressure spring and a pressing force adjusting means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printing part 7 Recording medium conveyance path 10.11 Transport roller 10a, 11a Rotating shaft 12, 13 Pressure roller 16 First pressure spring 17 Reference surface 18 Second pressure spring 19 Pressure adjusting means S Recording medium

Claims (3)

[Claims] 1. A recording medium transport path having a reference surface for guiding one side of a recording medium and passing through a printing section, and a center of a rotating shaft supported at a fixed position to transfer the recording medium to the recording medium transport path. A transport roller that transports along the transport roller, a pressure roller that is rotatably supported and rotatable with respect to the transport roller, and the pressure roller that is disposed at a plurality of locations along the axial direction of the pressure roller. A plurality of first pressure springs pressed against a conveyance roller, and the recording medium having a thickness equal to or greater than a predetermined thickness and positioned by the reference surface is inserted between the conveyance roller and the pressure roller. When pressed, at least the end of the pressure roller disposed at the upstream side of the printing unit on the reference surface side is pressed with the pressing force stronger than the pressing force of the first pressing spring on the transport roller side. A second pressure spring to pressurize the A recording medium transport device comprising: 2. The recording medium transport device according to claim 1, wherein the second pressure spring is provided between a plurality of pressure rollers disposed upstream and downstream of the printing unit. . 3. The recording medium transport device according to claim 1, further comprising a pressure adjusting means for adjusting the pressure of the second pressure spring.