JPH0564934A - Deflector of printer - Google Patents

Abstract

PURPOSE:To prevent paper which is variously different in thickness from floating up from a printing base while it is smoothly being carried by a method wherein a bending part having a specific radius of curvature is formed near a support component of a deflector body. CONSTITUTION:A deflector body 11 is supported cantileveringly with a support component 21, and a bending part 15 having a specific radius of curvature is formed near the support component 21. Thereby, a load acting on a tip part 13 of the deflector 11 becomes about a half of that of the conventional deflector body without any bending part when paper S is made to pass between the tip part 13 of the deflector body 11 and the printing base 1. Therefore, a variation quantity of paper-pressing force of the deflector body 11 becomes about a half of conventional one for variation in thickness of the paper to be extremely reduced. Consequently, the paper which is variously different in thickness can be prevented from floating up from the printing base 1 while it is being smoothly carried.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflector for a printer.

[0002]

2. Description of the Related Art FIG. 4 and FIG. 5 show a schematic structure of a conventional printer.

In these drawings, reference numeral 1 is a print stand, and 2 is a print head. Further, 5 is a deflector.

The deflector 5 has a base end portion 7 for mounting the nail 2.
2 has a deflector body 6 that is cantilevered by a support member 9 via a locking boss 23 and the like, and suppresses the floating of the paper S supplied to the stamp 1 at the tip portion 8 of the body 6. It is said that.

The deflector body 6 is formed of an elastic metal thin plate, a plastic sheet, or the like, and is pressed against the stamp base 1 by a predetermined pressing force due to its elasticity.

Then, the paper S supplied to the stamp bed 1
While being deflected by the deflector main body 6, it passes between the tip portion 8 of the main body 6 and the print stand 1 and is sent between the print head 2 and the print stand 1 for printing. At this time, the deflector body 6
Is used to print the sheet S with a force corresponding to the amount of bending due to its elasticity.
Press on. As a result, the sheet S can be fed between the print head 2 and the stamp pad 1 in a state where the paper sheet S is in close contact with the stamp pad 1, and high quality printing is ensured.

[0007]

By the way, recently,
There is an increasing opportunity to print sheets of various thicknesses (for example, single-cut sheets and slip sheets of plural sheets) with a single printing device. However, due to changes in the sheet thickness, the sheets S of the deflector main body 6 can be printed. The pressing force (paper pressing force) may fluctuate significantly, which may interfere with the paper conveyance.

For example, when a thick slip sheet is supplied to the stamp board 1, the sheet pressing force of the deflector body 6 becomes too strong and the slip sheet can pass between the deflector body 6 and the stamp board 1. Instead, a paper jam may occur or, on the other hand, if thin paper with weak stiffness is supplied, the paper feed pitch may be disturbed.

In view of the above circumstances, an object of the present invention is to provide a deflector for a printing apparatus which can prevent the sheet from having different thicknesses from being lifted from the printing plate while ensuring smooth conveyance.

[0010]

SUMMARY OF THE INVENTION The present invention relates to a deflector for a printing apparatus having a deflector main body which is supported by a supporting member in a cantilevered manner and which suppresses the floating of a sheet fed to a printing plate at its leading end. It is characterized in that a bent portion having a predetermined radius of curvature is formed in the vicinity portion.

[0011]

In the present invention, the sheet fed to the stamp board passes between the tip of the deflector body and the stamp board while bending the deflector body. At this time, the deflector body presses the sheet against the printing plate with a force (sheet pressing force) according to the amount of bending due to its elasticity, and prevents the sheet from floating.

Here, the sheet pressing force of the deflector body fluctuates when the thickness of the sheet changes, but the variation amount is greatly reduced by the curved portion of the body.

Hereinafter, it will be understood that the bending portion of the deflector body greatly reduces the fluctuation of the sheet pressing force with respect to the change of the sheet thickness as compared with the conventional case, and the deflector body having the bending portion 15 with a constant radius of curvature is shown in FIG. This will be described using 11.

The deflector body 11 is cantilevered by a support member 21, and a bent portion 15 having a constant radius of curvature is formed in the vicinity of the support member. The deflector body 11 is pressed against the stamp base 1 with a predetermined pressing force.

Here, the tip portion 1 of the deflector body 11
Assuming that the leading end portion 13 is bent by a length δ from the initial state by passing a sheet of arbitrary thickness between the sheet 3 and the printing plate 1, the following equation is established. δ = {KPr ³ / (3EI)} · (L / r + β) ³ (1) By modifying the above equation (1), P = {1 / (L / r + β) ³ } · {3EI / (Kr ³ )} · Δ ... (2) is obtained. Here, P is a load (acting and reacting with the sheet pressing force of the deflector body 11) acting on the tip portion 13 of the deflector body from the paper [kg], and E is a longitudinal elastic coefficient of the deflector body 11 (kg / mm ² ), I is the second moment of area of the deflector body 11 (m
m ⁴ ), L is the length (mm) of the straight portion on the free end side of the deflector body 11, r is the radius of curvature (mm) of the bent portion 15 of the deflector body 11, and β is the angle (ra of the bent portion 15
d) and K are correction coefficients (<1) determined by L / r and β described above.

From various experiments, it has been found that it is preferable to select L / r of 4 or more and β of π / 2 or more to achieve the object. Therefore, L / r = 4, β = π / 2
When P is calculated from the above equation (2) as (correction coefficient K = 0.72 in this case), P = {1 / (4 + π / 2) ³ } · [3EI / {0.72 · (L / 4 ) ³ }] · δ = 0.516 · (3EI / L ³ ) · δ (2) ′ On the other hand, as shown in FIG. 6, the tip portion 8 of the conventional deflector body 6 having no bent portion and the stamper 1 are provided. The amount of deflection δ ′ of the leading end portion 8 when a sheet having an arbitrary thickness is passed between and is: δ ′ = P′L ³ / (3EI) (3) P ′ = (3EI / L ³ ) · δ ′ is obtained. Here, P'is a load acting on the tip portion 8 of the deflector body from the sheet (which has an action / reaction relationship with the sheet pressing force of the deflector body 6) [kg], and E is a longitudinal elastic modulus (kg / mm ² ). , L is the length (mm) from the free end of the deflector body 6 to the base end. I is the moment of inertia of area (mm ⁴ ).

By the way, in FIGS. 3 and 6, the loads P and P'when a sheet of the same thickness is passed between the stamp pad 1 and the deflector body (11, 6) are as follows:
Since the flexure amounts (δ) are the same (δ = δ ′), P ′ = (3EI / L ³ ) · δ (3) ′. Therefore, the above equation (2) 'is P = 0.516P'. Thereby, the deflector body 1 according to the present invention
The load acting on the leading end portion 13 when the sheet is passed between the leading end portion 13 of No. 1 and the printing plate 1 (therefore, the pressing force of the sheet as a reaction) is about half the conventional load.

Therefore, even if the sheet thickness (deflection amount δ) changes, the variation amount of the sheet pressing force of the deflector body 11 is reduced to about half that of the conventional one, and is greatly reduced.

As a result, the sheet floating prevention function can be stably exhibited even when the sheet thickness changes.
It is possible to prevent the sheets from having different thicknesses from being lifted from the printing plate while ensuring smooth conveyance.

[0020]

An embodiment of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 and 2, the deflector of the printing apparatus according to this embodiment is cantilevered by a supporting member 21 and a deflector body for suppressing the floating of the paper S supplied to the stamp 1 at the leading end 13. Have 11. A bent portion 15 having a predetermined radius of curvature is formed in a portion of the deflector body 11 near the support member.

In this embodiment, the deflector body 1
1 is a support member 21 having a mounting hole 17 and a mounting claw 22.
It is fixed through. This deflector body 11
Is formed of a thin metal plate material having elasticity.
In addition, the deflector body 11 is fixed to the stamp base 1 with a predetermined pressing force.
Being pressed against.

The bent portion 15 of the deflector body 11
Are formed in an arc shape having a constant radius of curvature.
The curvature radius (arc radius) r of the bent portion 15 is set to 1/4 of the length L of the straight portion 16 of the deflector body 11. Further, the angle β of the bent portion 15 is set to π / 2 (rad) (note that in FIGS. 1 and 3, the bent portion 15 and the straight portion are provided for convenience of comparison with the conventional deflector (5). 16 are shown by appropriately changing the dimensional proportions.

Next, the operation will be described.

The sheet S supplied to the stamp 1 passes between the tip 13 and the stamp 1 while deflecting the tip 13 of the deflector body 11 by a predetermined amount (deflection amount δ).

At this time, the load P applied from the paper S to the tip portion 13 of the deflector body is P = 0.516 · (3EI / L ³ ) · δ from the above equation (2) ′. Here, a sheet having the same thickness as the above-mentioned sheet S is
Conventional deflector body tip without bending (8)
The load P'when passing between the seal 1 and the print stand 1 is P '= (3EI / L ³ ) .delta. From the above formula (3)', so the above formula is P = 0.516P ’ As a result, when a sheet S having an arbitrary thickness is passed between the deflector body front end portion 13 and the printing plate 1, the load acting on the front end portion 13 (therefore, the sheet pressing force as a reaction) is about half that of the conventional case. Become.

Therefore, even if the thickness of the sheet (deflection amount δ) changes, the variation amount of the sheet pressing force of the deflector body 11 is reduced to about half that of the conventional one, and is greatly reduced.

As a result, the sheet floating prevention function can be stably exhibited even when the sheet thickness changes.
It is possible to prevent the sheet from rising from the stamp 1 while ensuring smooth conveyance of sheets having different thicknesses.

In the present embodiment, the bent portion 15 of the deflector body 11 is formed in an arc shape, but it has a predetermined radius of curvature and the fluctuation of the sheet pressing force of the body 11 with respect to the change of the sheet thickness is effective. Any method may be used as long as it can be suppressed. For example, the bent portion 15 may be formed in an elliptical shape.

[0030]

According to the present invention, since the bent portion having the predetermined radius of curvature is formed in the vicinity of the supporting member of the deflector body, the sheet of different thickness is lifted from the stamp board while ensuring smooth conveyance. Can be prevented.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a perspective view for explaining a mounting state of a deflector according to an embodiment.

FIG. 3 is a diagram for explaining a relationship between a load acting on a deflector tip end portion according to the present invention and a deflection amount.

FIG. 4 is a view showing a conventional deflector.

FIG. 5 is a perspective view for explaining a mounting state of a conventional deflector.

FIG. 6 is a diagram for explaining a relationship between a load acting on a tip portion of a conventional deflector and a deflection amount.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stamp 11 Deflector main body 15 Bending portion 21 Support member

Claims (1)

[Claims] 1. A deflector of a printing apparatus having a deflector main body, which is cantilevered by a supporting member and suppresses floating of a sheet supplied to a stamp at its leading end, wherein a predetermined radius of curvature is provided in the vicinity of the supporting member of the deflector main body. A deflector for a printing apparatus, characterized in that a bent portion having the same is formed.