JPH0615889A - Platen - Google Patents

Abstract

PURPOSE:To reduce noise during printing by preventing the occurrence of paper rise in a printing device wherein a platen is employed. CONSTITUTION:An adhesive layer 23 is provided on the surface 24 of a platen 25 and, thereby, fan fold paper is stuck on the platen 25 through the adhesive force of the adhesive layer 23 during printing with the result that the rise of the fan hold paper is prevented and thus the vibration of fan hold paper caused by paper rise is prevented. In this manner, noise can be reduced during printing by preventing the occurrence of paper rise.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a platen for a printing apparatus such as an impact dot matrix printer, and more particularly to a platen which reduces noise during printing by allowing the platen to have an adhesive property.

[0002]

2. Description of the Related Art A conventional example of an impact dot matrix printer will be described with reference to FIGS. FIG. 3 is a front view of a printing unit of a conventional printer capable of printing 136 digits, and FIG. 4 is a line AA of FIG.
FIG. 5 is a cross-sectional view showing a cross section, and FIG. 5 is a cross-sectional view showing the BB cross section of FIG. 3. The fan hold paper 17, which is a paper, is sent by the tractor 2, wound around the platen 3, printed by the print head 4, further sent, and enters the paper discharge mechanism 5. The paper discharge mechanism 5 has a serrated cross section.
0, a paper discharge roller shaft 11, a paper discharge roller unit 9 including a gear 14 that is a power transmission unit, a paper discharge cover 6,
The discharge plate 7 includes a discharge roller unit 9, a discharge cover 6, screws 13 for fixing the discharge plate 7, and a frame 12 for rotatably holding the discharge roller unit 9. The positional relationship between the rib portion 6b of the paper discharge cover 6 and the paper discharge roller unit 9 does not change even if the paper discharge roller unit 9 rotates. The paper discharge cover 6 is fixed to the frame 12 with screws 13. The discharge roller unit 9 is a frame 12 having a bearing function.
It is configured to be rotatably held by the sheet discharge roller shaft 11 and its movement in the longitudinal direction is restricted. Fan hold paper 1
The paper discharge roller 10 made of rubber or a material having a high friction coefficient similar to that provided for pulling 7 is fixed to the paper discharge roller shaft 11 by fixing means such as press fitting so as not to idle. The discharge rollers 10 commonly use parts of the same shape. The gear 14 is also fixed to the paper discharge roller shaft 11. In FIG. 4, the discharge cover 6 is integrally formed with a rib portion 6b for guiding the fan hold paper 17 at its ridge portion to one plate portion 6a connected in a column direction, and at the 40th digit. Plate part 6 at this position
a extends to the bottom and has the longest length, and the rib portion 6b extends to the same position. The discharge cover 6 is about 40
The plate portion 6a rises upward as it goes to the smaller girder side (left side in FIG. 3) with the girder as a boundary,
Plate portion 6a as it goes to the larger girder side (right side in FIG. 3)
Has risen up and its length has become shorter. First, the wide fan hold paper 17 is guided between the paper discharge cover 6 and the paper discharge plate 7 at the 40th digit, and then the fan hold paper 17 is used.
This is because the fan hold paper 17 is gradually guided between the paper discharge cover 6 and the paper discharge plate 7 on the side of the girder smaller than 40 digits and on the side of the larger girder as the sheet is sent downstream. Further, the plate portion 6a and the rib portion 6b of the paper discharge cover 6 extend to the bottom at the 40th digit to guide the paper between the paper discharge cover 6 and the paper discharge plate 7 even when a narrow paper is used. This is because. The fan hold paper 17 is configured to be discharged and held by the pressure applied between the discharge cover 6 and the roller unit 9. The print head 4 is at the tip of the fan hold paper 17.
When it is sent downstream from the front of the sheet, the rib portion 6 of the paper discharge cover 6
The fan hold paper 17 is guided along the b
Enter between b and the discharge roller 10. As shown in FIG. 3, the rib portion 6b and the paper discharge roller 10 are arranged on both sides of the paper discharge roller 10 with a gap of L and with an overlap amount of M as shown in FIG. The force for pressing the fan hold paper 17 against the paper discharge roller 10 is determined by the gap L, the overlap amount M, and the spring property of the fan hold paper 17. The dynamic friction coefficient when the discharge roller 10 is in contact with the fan hold paper 17 and rotating and the pressing force determine the discharge force of the fan hold paper 17 due to friction. When the paper discharge roller 10 is stopped and printing is performed, the fan hold paper 17 is wound around the platen 3, so that a restoring force is applied to return to the original flat shape. Due to this restoring force, the fan hold paper 17 is fixed because its upstream side is positioned by the tractor 2, and therefore the fan hold paper 17 on the downstream side tries to return to the upstream side. The force with which the fan hold paper 17 returns is called the paper return force. When this fan hold paper 17 is pulled back,
The force that presses the fan hold paper 17 against the paper discharge roller 10 (the same as the force that presses the fan hold paper 17 against the rib portion 6b) and the first static friction force that is the product of the static friction coefficient between the fan hold paper 17 and the rib portion 6b. The second static friction force, which is the product of the force pressing the fan hold paper 17 against the paper discharge roller 10 and the static friction coefficient between the fan hold paper 17 and the paper discharge roller 10, acts. The frictional force obtained by adding the first static frictional force and the second static frictional force is called the total static frictional force. 5 is a cross-sectional view of the cross section BB in FIG. 3, and the contact length V between the rib portion 6b and the fan hold paper 17 is shorter than the AA cross section shown in FIG. The discharge force of the fan hold paper 17 is the gap L.
Along with the rib portion 6b of the fan hold paper 17 in the traveling direction
And the contact length V of the fan hold paper 17 also influences. If the contact length V is long, the fan-hold paper 17 is likely to be restrained, which has the effect of apparently increasing the spring property of the fan-hold paper 17. When the contact length V is short, the degree of freedom of the fan hold paper 17 is increased, and the elasticity of the fan hold paper 17 is apparently reduced. The paper ejection force on the small girder side is large because the contact length V is long, and the paper ejection force on the large girder side is the contact length V.
Is short, so it becomes small. Regarding the static frictional force of the fan hold paper 17 in the traveling direction, the fan hold paper 17 and the ribs 6
When the contact length V with b is long, the static friction force increases, and when the contact length V is short, the static friction force decreases. The static frictional force on the small girder side is large because the contact length V is long, and the static frictional force on the large girder side is small because the contact length V is short. In the conventional paper ejection mechanism 5 in which the lengths of the plate portion 6a and the rib portion 6b of the paper ejection cover 6 are changed depending on the girder position by using the paper ejection roller 10, the paper ejection side and the static friction force are small and large. Is unbalanced, and the fan hold paper 17 is skewed and wound around the platen 3 when pulled unbalanced by the discharge force, so that the paper floats from the platen 3 on the large girder side to cause paper floating, Further, since the total static friction force on the side of the large girder is smaller than the paper return force, the fan hold paper 17 returns further from the platen 3 on the side of the large girder, and the paper floats further.

[0003]

When the fan-holding paper 17 in the paper-floating portion floated from the platen 3 is hit by the wire of the head 4 as described above, the fan-holding paper 17 vibrates in a large area according to the paper-floating amount. It was making a lot of noise.

[0004]

In order to solve the above problems, the present invention is characterized in that an adhesive layer is provided on the platen surface.

[0005]

EXAMPLE An example of the platen of the present invention will be described with reference to FIGS. FIG. 1 is a sectional view of the platen of the present invention, in which a platen pipe 21 made of a metal pipe is surrounded by S
The platen rubber 22 made of BR (styrene-butadiene rubber) is press-fitted, and the surface of the platen rubber 22 is provided with an adhesive layer 23 coated with an adhesive. As the adhesive, there are acrylic rubber-based adhesive, SBR-based adhesive, and chloroprene-based synthetic rubber-based adhesive, which are diluted with a solvent and sprayed onto the platen surface 24, or coated or coated by roller coating. 2 is a sectional view of the same portion as FIG. Fan hold paper 1 which is paper
7 is sent by the tractor 2 and wound around the platen 25, and the fan hold paper 17 is attached to the platen 25 by the adhesive layer 2
It is attached weakly by the adhesive strength of 3. Fan hold paper 1
When the printing head 4 prints (a broad concept including graphs, image printing, etc. in addition to numbers, letters, etc.) by the printing head 4, the printing pressure causes the platen 25 to be strongly adhered to the platen 25, and the fan hold paper 17 at the time of printing is printed. The paper floating disappears, and the vibration of the fan hold paper 17 due to the paper floating also disappears. With this strong adhesive strength, the printing pressure disappears, and after a short time the adhesive strength weakens and becomes weak. When the paper is further sent, the fan hold paper 17 is wound around the platen 25, so that a restoring force for returning to the original flat shape acts. Due to this restoring force, the fan hold paper 17 separates from the platen 25 and enters the paper discharge mechanism 5. By providing the adhesive layer 23 on the surface of the platen rubber 22, it is possible to eliminate the floating of the fan-hold paper 17 at the time of printing, and to reduce the vibration of the fan-hold paper 17 due to the floating of the fan-hold paper 17. Noise due to can be reduced. Regarding the strength of the adhesive force of the adhesive layer 23, the adhesive force does not work when the paper is fed, and the paper floating at the time of printing can be eliminated even if the pressure is applied for a short time when the printing pressure is applied. That is, the pressure-sensitive adhesive has the same effect.

In the description of the present invention, the paper is a fan hold paper 1.
7 has been described as an example, the same effect can be obtained with a cut sheet, a postcard, or an envelope. Although the platen 25 of the present invention has been described by taking the case where the core is a metal pipe as an example, the same effect can be obtained with a solid core material, and the same effect can be obtained with a plastic material. The platen rubber 22 of the present invention is SBR
However, in addition, NBR (nitrile rubber), CR (chloroprene rubber), EPT (ethylene
Similar effects can be obtained with propylene / terpolymer) and Si (silicon rubber).

[0007]

As described above, in the platen of the present invention, by providing the adhesive layer on the surface of the platen, the paper floating of the paper at the time of printing can be eliminated, the vibration due to the paper floating of the paper can be eliminated, and the noise can be reduced. is there.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of a platen of the present invention.

FIG. 2 is a cross-sectional view of a printing unit when the platen of the present invention is used.

FIG. 3 is a front view of a printing unit of a conventional printer.

4 is a sectional view taken along line AA of FIG.

5 is a sectional view taken along line BB of FIG.

[Explanation of symbols]

 17 Fan Hold Paper 22 Platen Rubber 23 Adhesive Layer 24 Platen Surface 25 Platen

Claims (1)

[Claims] 1. A platen having an adhesive layer on the surface of the platen.