Paper sheet receptacle having transversely elastically supported barrier wall plate

The barrier wall device for paper sheets flying thereto with one edge posing as a front edge as discharged from a printing portion of a copying or printing machine to collide thereagainst is constructed to have a barrier wall plate elastically supported from a frame body by an elastic tensile support device extending perpendicularly to the direction of fly coming of the paper sheets, so that the barrier wall plate is biased in parallelism by expanding and inclining the tensile support device. The paper sheet receptacle is desirably adaptable to a high speed copying or printing machine so that paper sheet collision noise is lowered, with paper sheets received to form a well trued stack.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to the art of copying and printing machines, 
and more particularly, to a paper sheet receptacle for receiving paper 
sheets discharged from a printing portion of a copying or printing machine 
in a stacked up state. 
2. Description of the Prior Art 
A copying or printing machine is generally provided with a paper sheet 
receptacle having a barrier wall means adapted to be collided at with a 
front edge of a paper sheet flying as discharged from a printing portion 
of a copying or printing machine with the front edge as a forward end, and 
a stack floor means adapted to receive the paper sheet collided at and 
falling along the barrier wall means from below thereof, so that, when a 
plurality of paper sheets are successively discharged, they are 
successively stacked up in the paper sheet receptacle to form a stacked up 
body of the paper sheets. 
According to the recent development of copying and printing machines for 
higher speed operation, the paper sheets discharged from the printing 
portion of those machines fly at high speed toward the paper sheet 
receptacle with each one edge thereof posing a forward end, colliding at 
the barrier wall means of the paper sheet receptacle with a large 
momentum. In this case, if the barrier wall means has a rigid 
construction, a large collide sound is generated, and further the paper 
sheet is sprung back for a large distance by the reaction applied by the 
barrier wall means. Since the spring-back distance is much affected even 
by a small difference in the flying posture of each paper sheet as 
magnified by a corresponding difference of air resistance, the stacked up 
body of the paper sheets formed in the paper sheet receptacle shows a 
great disorder with scattered distances left between the front edges of 
the paper sheets and the wall surface of the barrier wall means. 
Against such a problem the conventional counter-measure is to attach a 
cushion sheet means made of sponge, rubber, or the like onto the surface 
of the barrier wall means where the front edges of the paper sheets 
collide. Such a cushion sheet attached onto the front surface of the 
barrier wall means lowers the collide sounds of the paper sheets to 
certain extent when the cushion sheet is constructed with a soft material 
having a low modulus of elasticity. However, when the cushion sheet is 
made so soft as a sufficient muffling effect is available, the positioning 
function of the barrier wall means against the front edges of the paper 
sheets lowers, so that the disorder of the paper sheets stacked up in the 
paper sheet receptacle increases. 
SUMMARY OF THE INVENTION 
In view of the above-mentioned problems concerned with the paper sheet 
receptacles of high speed copying or printing machines, it is a principal 
object of the present invention to provide a paper sheet receptacle of 
copying or printing machines improved so as to collect the paper sheets 
fly coming at high speed as discharged from the printing portion of high 
speed copying or printing machines with each one front edge posing a 
forward end silently and well trued up. 
According to the present invention, the above-mentioned object is 
accomplished by a paper sheet receptacle of a copying or printing machine 
comprising a barrier wall means for a paper sheet flying as discharged 
from a printing portion of the machine to collide thereat with a front 
edge thereof, and a stack floor means for receiving the paper sheet 
collided at and falling along said barrier wall means from below thereof, 
wherein said barrier wall means comprises a frame body, a barrier wall 
plate, and an elastic tensile support means interposed between said frame 
body and said barrier wall plate so as to pull said barrier wall plate 
toward said frame body at at least a pair of up and down or left and right 
edge portions thereof in an orientation substantially perpendicular to the 
direction of flying of the paper sheet such that said barrier wall plate 
biases in parallelism while expanding and inclining said tensile support 
means when the paper sheet collided at said barrier wall plate. 
The above-mentioned tensile support means may comprise a rubber sheet or 
tensile coil springs connected with said frame body and said barrier wall 
plate by pivot means.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In the following, the invention will be described in more detail with 
respect to the embodiments thereof with reference to the accompanying 
drawings. 
In order to lower the sound of collision generated at a collision of the 
front edge of the paper sheet at the barrier wall means, it is a matter of 
course that the barrier wall means should present a surface as much softer 
as possible against the front edge of the paper sheet. The matter that the 
barrier wall means presents a soft surface against the front edge of the 
paper sheet means that the modulus of elasticity in the elastic retreat of 
the wall surface due to the pressing by the front edge of the fly coming 
paper sheet is low. When the barrier wall plate is supported by the 
elastic tensile support means at at least a pair of up and down or left 
and right edge portions thereof as pulled by the elastic tensile support 
means in the orientation substantially perpendicular to the direction of 
fly coming of the paper sheet, such that the barrier wall plate biases in 
parallelism by expanding and inclining the elastic tensile support means, 
it is possible that the modulus of elasticity of the reaction force acting 
against the paper sheet at the moment of the collision of the front edge 
of the paper sheet at the barrier wall plate is made very low, while the 
distance of the temporary retreat of the barrier wall plate due to the 
kinetic energy of the fly come paper sheet is made very small and highly 
stabilized, so that the truing up of the front edges of the stacked up 
paper sheets by the barrier wall means is accomplished silently at high 
precision. 
In more detail, referring to FIG. 1 of the accompanying drawings, it is to 
be understood that 100, 200 and 300 are the frame body, the barrier wall 
plate and the tensile support means of the paper sheet receptacle, 
respectively. The tensile support means is a membrane of a rubber material 
having a relatively low modulus of elasticity, firmly mounted to the frame 
body 100 at a pair of side edge portions thereof. It is desirable that the 
barrier wall plate is a light-weighted plate member having a soft surface 
to contact with the paper sheet. The barrier wall plate biases in 
parallelism as a whole as depicted by broken lines in the figure when it 
is pushed by the front edge of a paper sheet S fly come as shown by an 
arrow. In order that the barrier wall plate is pushed back by as small a 
force as possible to bias in parallelism as a whole due to the kinetic 
energy of the paper sheet, it is desirable that the mass of the barrier 
wall plate is as small as possible. Such a light-weighted and hard barrier 
wall plate is available from styrol, foamed vinyl chloride, etc. Or 
otherwise, for the convenience of manufacture, the barrier wall plate may 
be formed as an integral part of a rubber membrane in which a central 
portion of the membrane is made thicker than peripheral portion adapted to 
work as the elastic tensile support means, wherein the central portion is 
made thick enough to be deemed as a substantially non-expandable plate 
member. In this case, it is desirable that the barrier wall plate portion 
is given a rigidity by ribs in a lattice form or the like, a frame work of 
steel wires, bundle of fibers, cloth, etc. being embedded therein, so that 
the ratio of the modulus of elasticity to the mass of the barrier wall 
plate portion is increased. When the barrier wall plate 200 is constructed 
to have a less mass, it presents a less resistance due to its inertia 
against being pushed back by the paper sheet. Further, it will be more 
desirable that the barrier wall plate is made of a perforated material or 
bored with appropriate wind through openings so that the air resistance 
applied thereto in its retreating movement is reduced. 
Expressing in FIG. 1 that a pair of opposite side edges of the barrier wall 
plate 200 are each distant from each of the corresponding fixed opposite 
side edges of the tensile support means 300 (called simply rubber membrane 
300 hereinbelow for convenience) by a distance r.sub.o, it is assumed 
that, by a substantially uniform collision of the front edge of the paper 
sheet S come flying from up to down as viewed in the figure, the barrier 
wall plate 200 biases downward in the figure in parallelism, while 
substantially maintaining its flat shape, with a corresponding expansion 
and inclination of the opposite side edge portions of the rubber membrane 
300 until the barrier wall plate and the rubber membrane 300 take the 
position depicted by broken lines in the figure. Expressing the distance 
of the parallel biasing of the barrier wall plate 200 by d, the angle of 
inclination of the opposite side edge portions of the rubber membrane 300 
by .theta., and the length of the expanded and inclined portion of the 
rubber membrane by r, the following relationships are established: 
EQU d=r.sub.0 *tan .theta. 
EQU r=r.sub.0 /cos .theta. 
When, for example, r.sub.0 is 10 mm, assuming that the rubber membrane 300 
does not expand at the portion thereof laid one over the other with the 
barrier wall plate 200 as it is adhered thereto, the value of d and the 
expansion of the opposite side edge portions of the rubber membrane 300, 
i.e. r- r.sub.0 =.DELTA. r change against .theta. of 0.degree., 5.degree., 
10.degree., 15.degree., 20.degree. and 25.degree. as shown in the 
following table: 
______________________________________ 
.theta. 
tan .theta. 
cos .theta. 
1/cos .theta. 
d .DELTA.r 
______________________________________ 
0 0 1 1 0 0 
5 0.087 0.996 1.004 0.87 0.04 
10 0.176 0.985 1.015 1.76 0.15 
15 0.268 0.966 1.035 2.68 0.35 
20 0.364 0.940 1.064 3.64 0.64 
25 0.466 0.906 1.104 4.66 1.04 
______________________________________ 
By plotting the figures of the table, a graph such as shown in FIG. 2 is 
obtained. As will be understood from the graph of FIG. 2, as the distance 
d increases starting from 0, in a range where d is very small near 0, the 
rate of increase of .DELTA. relative to the increase of d is very low, 
that is, when the barrier wall plate biases in parallelism, the rubber 
membrane is not substantially expanded, such that the ratio of the elastic 
resistance applied by the opposite side edge portions of the rubber 
membrane 300 to the barrier wall plate against its biasing to the amount 
of the biasing, i.e. an apparent modulus of elasticity of the barrier wall 
means against the biasing thereof, remains in a very small value close to 
0. This means that at the instant when the front edge of the paper sheet S 
collides at the barrier wall plate 200 and in a minute period succeeding 
thereto during which there is a probability of generating a sound of 
collision, the barrier wall plate is very soft against the paper sheet. 
Therefore, when the total mass of the barrier wall plate 200 and 
substantially the part of the rubber membrane 300 laid over the barrier 
wall plate is made small enough against the momentum of the paper sheet S 
at the time of collision (mass times velocity), the impact force at the 
collision of the paper sheet S to the barrier wall plate 200 is made very 
low, such that the sound of collision can be suppressed near 0. Once the 
front edge of the paper sheet S has contacted the surface of the barrier 
wall plate 200, even how the elastic reaction which the assembly of the 
barrier wall plate 200 and the rubber membrane 300 presents against the 
forward movement of the paper sheet increases, the sound of collision is 
no longer generated. 
Further, as will be understood from the graph of FIG. 2, Ar increases 
rapidly along with increase of d, so that the elastic reaction which the 
assembly of the barrier wall plate 200 and the rubber membrane 300 
presents against the further forward movement of the paper sheet S under 
the expansion and inclination of the opposite side edge portions of the 
rubber membrane 300 increases rapidly along with the further forward 
movement of the paper sheet S. Therefore, in an example such as shown 
above where the value of r.sub.0 is 10 mm, when the front edge of the 
paper sheet proceeds only 3 mm from the position of the instant of 
collision at the barrier wall plate 200, the reaction force increases to 
about 10 times of that which acts at a position proceeded about 1 mm from 
the position of the instant of collision. 
Thus, according to the construction of the present invention, a barrier 
wall means is available such that it is very soft at the instant of 
collision of the front edge of the paper sheet thereto and in a minute 
period subsequent thereto, while rapidly hardening thereafter, so that 
even when there is a substantial dispersion in the fly coming speed and/or 
the posture of respective paper sheets at the instant of collision to the 
barrier wall means, the finally biasing distance of the barrier wall means 
is very small and the difference in the finally biasing distance for the 
respective paper sheets remains very small, such that the positions of the 
respective paper sheets received in the paper sheets receptacle after the 
dissipation of the kinetic energy thereof change little against one 
another, providing a well trued up stack of paper sheets. 
FIG. 3 is a perspective view showing an embodiment of a printing machine 
equipped with the paper sheet receptacle according to the present 
invention. The printing machine herein shown is manufactured and sold by 
the applicant, by which a stencil sheet is perforated according to an 
original and a stencil printing is carried out by using the perforated 
stencil sheet. It will be apparent that the paper sheet receptable 
according to the invention may be assembled in a copying machine in the 
same manner. The inside constructions of such a printing machine is 
already known in various embodiments by patent and utility model 
publications including those filed by the same assignee as the present 
application. A relatively new model of such a machine is shown in Japanese 
Patent Laid-open Publication 7-137420 based upon Japanese Patent 
Application 5-306031 filed by the same assignee as the present 
application. Since the present invention does not relate to the 
constructions of the copying and printing portions at the inside of the 
body 1 of such a copying-printing machine but relates to the paper sheet 
receptacle 2 for collecting print sheets flying thereto with one edge 
thereof posing as the front edge as discharged from the printing portion 
thereof, particularly the barrier wall means 3, the detailed descriptions 
about the constructions at the inside of the body 1 of the 
copying-printing machine will be omitted. 
As exemplarily shown in FIG. 3, the paper sheet receptacle 2 of this kind 
comprises, as a general construction, a barrier wall means 3 for the paper 
sheet flying thereto as discharged from the printing portion in the body 1 
with one edge thereof posing as the front edge to collide thereagainst, 
and a stack floor means 4 for receiving the print sheet colliding at and 
descending along the barrier wall means from under thereof, with the 
barrier wall means 3 being mounted to the stack floor means 3 so as to be 
adjustable of the position thereof with respect to the stack floor means 
along the direction of discharge of the paper sheet. An invention with 
regard to a device for making such an adjustment of the barrier wall means 
is shown in Japanese Patent Application 5-306037 (Japanese Patent 
Laid-open Publication 7-137916) filed by the same assignee as the present 
application. Further, such a paper sheet receptacle is, in most cases, 
equipped with side wall means 5 and 6 for truing opposite side edges of 
the paper sheets stacked up in the paper sheet receptacle, as shown in 
FIG. 1. 
FIG. 4 is a longitudinally sectional view of an embodiment of the barrier 
wall means constructing an essential portion of the present invention, and 
FIG. 5 is an exploded perspective view thereof. The barrier wall means of 
this construction may be mounted to the stack floor means 4 in a manner 
disclosed in the specification and the drawing of the above-mentioned 
Japanese Patent Application 5-306037 (Japanese Patent Laid-open 
Publication 7-137916) so as to be adjustable with respect to the position 
thereof in the direction of discharge of the print sheet. Since the 
construction for mounting the barrier wall means to the stack floor means 
is not an essential portion of the present invention, illustration and 
descriptions of the details of such a mounting construction will be 
omitted for the brevity of the specification and the drawing. 
In these figures, the barrier wall means generally designated by reference 
numeral 3 comprises a barrier wall plate 10 of a rectangular outer contour 
having a surface facing toward the fly coming direction of the paper sheet 
to let the front edge thereof collide thereagainst. The barrier wall plate 
10 is elastically supported by an elastic membrane 12 having a rectangular 
outer contour and adhered at the rear face thereof to a central portion of 
the elastic membrane. The rectangular outer contour of the elastic 
membrane 12 is made larger than the rectangular outer contour of the 
barrier wall plate 10 so that an annular edge area is left along the four 
edges of the barrier wall plate, the annular edge area being mounted to a 
frame body 14 at a peripheral portion thereof as described in detail 
hereinbelow. The barrier wall plate 10, elastic membrane 12 and frame body 
14 correspond to the barrier wall plate 200, rubber membrane 300 and frame 
body 100 of FIG. 1, respectively. 
The frame body 14 has a construction of assembly made of a first frame 
member 18 providing a front annular edge portion of the barrier wall means 
with two openings 16 for receiving two barrier wall plates 10, and a 
second frame member 20 having an annular edge portion to meet with the 
annular edge portion of the first frame member 18 and adapted to cover the 
rear faces of the two barrier wall plates. In more detail, the frame 
member 18 constructing the front face of the barrier wall means and the 
frame member 20 constructing the rear face of the barrier wall means are 
abutted to one another in alignment such that a fringing portion 22 formed 
along the outer periphery of the frame member 18 meets with a fringing 
portion 24 formed along the outer periphery of the frame body 20, except a 
portion extending along the lower end thereof, with four pins 26 formed in 
the frame body 18 engaging the corresponding tubular pin receiving holes 
28 formed in the frame body 20, so that the assembly of the two frame 
members is readily accomplished in alignment. The pin receiving holes 28 
are each a cupshaped projection provided on the inside of the frame member 
20 as viewed from the inner side of the assembly, with a through opening 
being formed at a central portion of the bottom of the cup. The pin 26 of 
the frame member 18 is formed with a threaded bore, so that the frame 
members 18 and 20 are laid one over the other with the four pins 26 
engaged in the corresponding pin receiving holes 28, while sandwiching the 
elastic membrane 12 therebetween and clamping it together by four pieces 
of screws being screwed into the threaded bore of the pins 26 from the 
outer side of the frame member 20 through the bottom opening of the 
cut-shaped pin receiving holes 28, thereby immediately providing a 
complete firm barrier wall construction assembled of the opposite frame 
members. 
The elastic membrane 12s are disposed relative to the frame member 18 such 
that the barrier wall plates 10 attached thereto are each passed through 
each of the openings 16, while the annular edge portions 32 thereof are in 
contact with an annular edge portion 34 of the frame member 18 around the 
openings 16 as pressed thereagainst by a rectangular annular rib 36 
provided at the inside of the frame member 20, so that each of the barrier 
wall plates 10 is firmly supported at the annular peripheral edge thereof 
by the elastic membrane 12, when the frame members 18 and 20 are clamped 
together by the screws 30. The elastic membrane 12 is formed with openings 
38 in its upper and lower edge portions to let the pins 26 pass 
therethrough, so that, as will be understood from FIG. 4, the two elastic 
membranes 12 can be assembled to the frame body 18 at the predetermined 
position thereof by the engagement of the pins 26 into the openings 38 
before the frame members 18 and 20 are clamped together by clamping the 
upper and lower edge portions of the elastic membranes 12 between the edge 
portions 34 and the ribs 36. 
For further detail, as will be understood from FIG. 4, the surface of the 
barrier wall 10 for contacting with the front edge of the paper sheet is 
so shaped as to smoothly continue to a face 40 which the frame body 18 
presents along a lower edge thereof, so that the print sheet collided at 
the barrier wall plate at the front edge thereof descends with the front 
edge thereof moving along the surface of the barrier wall plate 10 and 
further along the surface 40 of the frame member 18 when the height of the 
stack of print sheets is still low. The front surface of the frame member 
18 may be disposed to incline slightly backward so that the front surface 
40 of the lower end thereof is in the same plane as a surface 42 of an 
upper edge portion thereof. 
FIG. 6 is a longitudinally sectional view showing another embodiment of the 
barrier wall means constructing an essential portion of the paper sheet 
receptacle according to the present invention in a somewhat diagrammatic 
fashion. In this embodiment, the barrier wall plate 10 is elastically 
supported at upper and lower ends thereof by tensile coil springs 44. The 
connecting portion between the barrier wall plate 10 and the tensile coil 
springs 44 and the connecting portion between the tensile coil springs 44 
and the frame body 14 incorporate pivot means 46 and 48, respectively, so 
that the tensile coil springs 46 can lightly incline for a parallel 
movement of the barrier wall plate 10 in the direction of thickness 
thereof. 
Although the present invention has been described with respect to some 
embodiments thereof, it will be apparent for those skilled in the art that 
other similar embodiments are possible within the technical concepts of 
the present invention.