U.S. patent number 3,835,770 [Application Number 05/248,368] was granted by the patent office on 1974-09-17 for compact flying printer.
This patent grant is currently assigned to Kabushiki Kaisha Suwa Seikosha, Shinshu Seiki Kabushiki Kaisha. Invention is credited to Yoshifumi Gomi, Tadayoshi Shimodaira.
United States Patent |
3,835,770 |
Shimodaira , et al. |
September 17, 1974 |
COMPACT FLYING PRINTER
Abstract
A compact flying printer having a continuously rotating print
drum and ratchet wheel, a trigger lever positionable to be struck
by a tooth of said ratchet wheel and a hammer lever driven by said
trigger lever and provided with a print hammer at its end. The
trigger lever is formed with a linear guide portion for regulating
the motion thereof and an energy transmitting portion projected for
transmitting energy from said ratchet wheel to said hammer
lever.
Inventors: |
Shimodaira; Tadayoshi (Suwa,
JA), Gomi; Yoshifumi (Chino, JA) |
Assignee: |
Kabushiki Kaisha Suwa Seikosha
(Tokyo, JA)
Shinshu Seiki Kabushiki Kaisha (Nagano-ken,
JA)
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Family
ID: |
27281411 |
Appl.
No.: |
05/248,368 |
Filed: |
April 28, 1972 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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118427 |
Feb 24, 1971 |
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Foreign Application Priority Data
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Feb 27, 1970 [JA] |
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45-16451 |
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Current U.S.
Class: |
101/93.31;
101/107; 400/161; 400/221.2; 400/364; 400/636.2; 101/100; 226/120;
400/219.2; 400/225; 400/600.1 |
Current CPC
Class: |
B41J
9/10 (20130101); B41J 1/34 (20130101); G06C
11/04 (20130101) |
Current International
Class: |
B41J
9/10 (20060101); B41J 9/00 (20060101); B41J
1/00 (20060101); B41J 1/34 (20060101); G06C
11/00 (20060101); G06C 11/04 (20060101); B41j
011/00 () |
Field of
Search: |
;101/93C,96,100,107
;197/127R,133R,138,151,156,160,169,162 ;226/120 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Pulfrey; Robert E.
Assistant Examiner: Eickholt; E. H.
Attorney, Agent or Firm: Blum, Moscovitz, Friedman &
Kaplan
Parent Case Text
This is a division, of application Ser. No. 118,427, filed Feb. 24,
1971.
Claims
What is claimed is:
1. In a printing device having printing means, drive means for said
printing means and means for incrementally, longitudinally
advancing paper relative to said printing means, the improvement in
said paper advancing means which comprises a continuously rotating
member driven by said drive means; a transmitting member
displaceable between a first rest position and a second position;
first coupling means operatively engaging said transmitting member
and said rotating member for the selective displacement of said
transmitting member between said first and second positions in
response to the rotation of said rotating member, said first
coupling means including a first lever mounted on said transmitting
member for pivotable displacement into and out of operative
engagement with said rotating member; a first spring means biasing
said first lever into said operative engagement; first detent means
mounted on said transmitting means for releasably retaining said
first lever out of operative engagement with said rotating member;
and selective releasing means coupled to said first detent means
for selectively releasing said first detent means to permit the
displacement of said first lever into operative engagement with
said rotating member for the displacement of said transmitting
member; second spring means coupled to said transmitting member for
the storage of energy during the displacement thereof between said
first and second positions; means disengaging said transmitting
member and said rotating member at said second position to release
said transmitting member for return to said first position in
response to the energy stored in said second spring means; paper
engaging means for the displacement of said paper; and second
coupling means operatively engaging said transmitting means and
said paper engaging means during said displacement from said second
to said first position for operative displacement of said paper
engaging means.
2. A printing device as recited in claim 1, wherein said
disengagement means includes a fixed member in the path of said
first lever during the displacement of said transmitting member
from said first to said second position for pivotably displacing
said first lever out of operative engagement with said rotating
member and into locking engagement with said first detent means at
said second position.
3. A printing device as recited in claim 2, wherein said first
lever includes an inclined camming surface for engagement against
said fixed member.
4. A printing device as recited in claim 3, wherein said driving
means includes a drive shaft, said drive shaft defining said
disengaging means fixed member.
5. A printing device as recited in claim 1, wherein said rotating
member is a gear, said first lever being formed with a portion
defining a rack for cooperation with said gear for the displacement
of said transmitting member.
6. A printing device as recited in claim 1, wherein said selective
releasing means includes solenoid means for the selective
displacement of said first detent means.
7. A printing device as recited in claim 1, wherein said printing
device is a flying printer having a continuously rotating print
drum and a rotating shaft supporting said print drum, said rotating
member being mounted on said print drum shaft for rotation
therewith.
8. A printing device as recited in claim 1, including an inked
ribbon, ribbon engaging means for incrementally, longitudinally
advancing said ribbon relative to said printing means; and means
operatively coupling said ribbon advancing means and said
transmitting member for the longitudinal displacement of said
ribbon in response to the displacement of said transmitting member
from its second to its first position.
9. A printing device as recited in claim 8, wherein said means
coupling said transmitting member and said ribbon advancing means
includes a second pivotably mounted lever having a pair of arms, a
first of said arms operatively engaging said transmitting member
for the pivotable displacement of said second lever between first
and second positions corresponding to the first and second
positions of said transmitting member, said second arm being
operatively coupled to said ribbon advancing means; and spring
means coupled to said second lever for biasing said second lever to
its first position.
10. A printing device as recited in claim 8, including ribbon shift
means for selectively laterally displacing said ribbon relative to
said printing device, said ribbon shift means including ribbon
support means pivotably mounted for displacement between first and
second positions representative of two laterally shifted positions
of said ribbon; means biasing said ribbon support means in said
second position; second detent means coupled to said ribbon support
means for releasably retaining said ribbon support means at said
first position; means for the selective displacement of said second
detent means to release said ribbon support means for displacement
from its first to its second position; and means coupling said
transmitting member and said ribbon support means for displacing
said ribbon support means from its second to its first position at
which it is captured by said second detent means during the
displacement of said transmission member from its first to its
second position.
11. A printing device as recited in claim 10, wherein said means
for selectively releasing said second detent means includes second
solenoid means.
Description
BACKGROUND OF THE INVENTION
This invention relates to a compact flying printer utilized in
electronic desk calculators and other numerical read out devices.
In such printers, the hammer strikes a selected character from an
array of characters provided in columnar fashion on the periphery
of a continuously rotating print drum. However, the known
arrangements of this type of printer have several substantial
drawbacks. Specifically, shear will occur in the printing process
if the contact time between the hammer and the print drum is too
great, resulting in smudged printing or ripped paper. In order to
overcome this defect, the contact time of the hammer with the
character must be shortened, thereby increasing the operating speed
of said hammer. In the conventional printers of the type described
the hammer is directly operated by electromagnets, and an increase
in the operating speed of the hammer requires an increase in the
size and power of said electromagnets. However, an increase in the
size and power of the electromagnets results in an increase in the
volume of the printer and requires increased electric power
consumption, and is therefore undesirable. To avoid the
above-described defects, a device wherein the energy for printing
can be obtained from a continuously rotating body is utilized.
SUMMARY OF THE INVENTION
The object of this invention is to provide a high speed compact
flying printer.
Another object of this invention is to provide a flying printer
with precise operation.
A further object of this invention is to provide a flying printer
of simple construction with minimum number of components, which
enables easy assembly and mass scale production.
A further object of this invention is to provide a flying printer
with small electric power consumption.
In the compact flying printer according to the invention, the
hammer and hammer lever are made in one piece. In order to position
the hammer exactly against the character on the print drum, a guide
member having a guide groove or guide hole arranged in zig-zag form
is provided. The trigger lever is formed with a guide portion in
linear form and a transmitting portion projected from said guide
portion. One end of the trigger lever is projected from the other
surrounding parts and so that said trigger level can be easily
taken out after finishing assembly of the printer. The trigger
lever strikes against the trigger lever stopper at its sloping
portion to secure precise operation. Inked ribbon winding, color
changing of ribbon and paper feeding are driven by the motor device
of the printer. The above devices are mounted on one side of the
printer. The main components for printing are housed in a unit. A
guide plate for paper feeding is wave formed to advance the paper
smoothly. Thus, clear printing can be obtained.
BRIEF DESCRIPTION OF THE DRAWINGS
For a fuller understanding of the invention, reference is had to
the following descriptions taken in connection with the
accompanying drawings, in which:
FIG. 1 is a schematic representation showing the operation of a
conventional flying printer;
FIGS. 2 and 3 are perspective views of the flying printer according
to the invention;
FIG. 3-a is a front elevational view of a hammer lever guide plate
of the flying printer of this invention;
FIGS. 4, 5, 6, 7 and 8 are sectional views describing the operation
of the flying printer of this invention;
FIG. 9 is an enlarged view of the regulating plate of the flying
printer of this invention;
FIG. 10 is a sectional view of the flying printer of this
invention;
FIG. 11 is a schematic diagram showing the construction of the
driving shaft of the flying printer of this invention;
FIG. 12 is a perspective view showing the electromagnets and base
member thereof of the invention;
FIG. 13 is a partial perspective view of the detecting device of
the flying printer of this invention;
FIG. 13-a is a sectional view of the device shown in FIG. 13;
FIG. 14 is a partial perspective view showing paper feeding
mechanism and ribbon feeding mechanism;
FIGS. 15, 16 and 17 show the operation of the arrangement of FIG.
14;
FIG. 18 is a perspective view showing color change of the inked
ribbon;
FIGS. 19 and 20 show the operation of the arrangement of FIG.
18;
FIG. 21 is a sectional view showing the paper guide of a
conventional type of flying printer;
FIG. 22 shows the effect caused by the arrangement of FIG. 21;
FIG. 23 is a sectional view showing a paper guide device according
to the invention; and
FIG. 24 is another sectional view showing a paper guide device
according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 is a schematic representation of one column of a
conventional type of a flying printer wherein 301 is a print
hammer, 302 a hammer lever, and 303 a rotary axis for said hammer
lever. Disposed immediately below hammer 301 is a print drum 304
having print characters spaced apart on the peripheral surface
thereof. The print drum 304 and a print drum gear 305 are mounted
for rotation on a print drum shaft 306. The print drum gear 305
meshingly engages an intermediate pinion 307 which is adapted to
drive an intermediate gear 308 fixed thereto. 310 is a ratchet
wheel, 311 a pawl extended from the ratchet wheel, 312 a trigger
lever pin A, and 313 a trigger lever pin B. A trigger lever 314 is
formed with a tail portion 315 and a projection 316. 317 is a
trigger lever stopper. A trigger lever guide 318 is provided to
guide the trigger lever 314 during displacement of the trigger
lever. A spring 319 is secured between lever 314 and a fixing point
320 for biasing the end 338 of the trigger lever 314 out of the
locus of the pawl 311. The end 321 of the arm of hammer lever 302
is engageable by a shoulder 322 of the trigger lever 314 upon
linear displacement of the latter, causing the hammer lever 302 to
pivot and the hammer 301 to strike print drum 304 via paper 330,
upon which a character is to be imprinted, and an inked ribbon 331
which are interposed between the hammer 301 and the print drum 304.
A timing lever 323 is disposed to engage tail 315 of trigger lever
314 and is pivotably mounted on a timing lever shaft 324. Fixed to
the timing lever 323 is a magnetic plate 325 movement of which is
controlled by electromagnets 326 and 327. A spring 328 is mounted
between the corner of hammer lever 302 and a fixing point 329 to
normally bias said hammer lever in the position shown with hammer
301 spaced from print drum 304. 329 is a fixing point of spring
328, 332 is a center of gravity of said trigger lever.
In FIG. 1, only one column is illustrated by way of example.
However, an actual printer would include the desired number of
columns, each of which would comprise a hammer 301, a hammer lever
302, a trigger lever 314, a trigger lever spring 319, a timing
lever 323, a magnetic plate 325, electromagnets 326 and 327, and a
hammer lever spring 328.
When the flying printer is activated but no timing signals are
applied to the electromagnets or to the paper advance mechanism, a
motor continuously rotates the ratchet wheel 310 in the direction
of arrow 333, thereby also rotating the print drum 304 in the same
direction through the intermediate gears 307 and 308. On the
surface of the print drum 304, many columns each including all the
characters to be printed are disposed. Pawl 311 is provided on the
surface of the ratchet wheel 310. The gear ratio between the
ratchet wheel 310 and the print drum 304 is selected so that the
pitch time of the pawl equals the circumferential spacing of the
characters on the peripheral surface of the print drum 304. Thus,
each rotation of the pawl corresponds to the advancing of one
character on the print drum. For example, if there are 16
characters on the print drum and one pawl is on the ratchet wheel,
the rotational ratio between the ratchet wheel and the print drum
is 16:1. In non-printing condition, the electromagnets 326 and 327
are not actuated electrically, and the trigger lever 314 is biased
to the direction of the spring fixing point 320 by means of the
spring 319, and is positioned by means of the trigger lever guide
318. Therefore, the end 338 of the trigger lever 314 is placed
lower than the position shown in FIG. 4, and the pawl 311 does not
engage with the end 338 of the trigger lever 314. Magnetic plate
325 is biased to the direction of the arrow 336 by the force of the
spring 319.
In order to print a desired character on the paper 331 by means of
the hammer 1 when the print command enters in the control circuit,
the electromagnets 326 and 327 are energized immediately before the
desired character on the peripheral surface of the print drum 304
passes under the hammer 301. The energization of one of said
electromagnets 326 and 327 rotatably displaces its respective
magnetic plate 325 in the direction of the arrow 337. This rotating
force is transmitted to the trigger lever 314 through the trigger
lever tail 315. Thus the trigger lever 314 rotates in the
counterclockwise direction around the trigger lever guide 318 and
touches the trigger lever guide 312 to be positioned thereby.
FIG. 1 shows this state. When the ratchet wheel 310 further
rotates, the pawl 311 engages with end 338 of trigger lever 314.
The linear displacement of the trigger lever 314 is transmitted to
the arm 321 of the hammer lever 302 by means of the shoulder 322 of
said trigger lever. Said hammer lever is in turn rotated in the
counterclockwise direction causing the hammer 1 to strike the print
drum through inked ribbon 331 and paper 330 at the moment when the
desired character is positioned under said hammer.
This type of printer, as will be clear from the above description
and FIG. 1, has disadvantages as follows. Since one end 338 of said
trigger lever is struck by the pawl 311 and the other end of said
trigger lever engages with the timing lever 323, the trigger lever
occupies a large space in the longitudinal direction due to its
long shape and it is not suitable as a compact flying printer. As
the guide members 312, 313 and 318 for the trigger lever are
separately mounted, construction becomes complicated. Besides, as
the trigger lever is encompassed by the guide members 312, 313 and
318 and the stopper 317, assembly becomes difficult. It is
necessary to remove said guide member in case of repair. The
engaging point between the trigger lever stopper 317 and the
trigger lever projection 316 is on the upper portion of the center
of gravity of motion direction, so motion of the trigger lever
after striking aginst the stopper 317 is large and so it is not
suitable for a compact printer.
The present invention seeks to eliminate the above defects.
FIG. 2 is a perspective view of the printer according to the
invention, wherein 101 and 101' are main frames, 102 a hammer lever
guide plate for guiding the hammer levers 3 in a fixed position, 5
a print drum, 108 a paper, 112 a paper feeding roller for advancing
the paper, 113 an inked ribbon, 114 a spool for said inked
ribbon.
FIG. 3 is a perspective view of the printer according to the
invention viewed from the other side having motor device 105
mounted thereon.
FIGS. 4, 5 and 6 show the construction of one column according to
the invention. 1 is a ratchet wheel rotating continuously at a
constant speed driven by the motor. The trigger lever 2 is guided
by the trigger lever guides 8-3 and 8-6. The trigger lever is
biased out of the locus of the ratchet wheel 1 when the plunger 11
is not energized. The trigger lever 2 and the trigger lever
regulating plate 8 have stopper faces 2-1, 2-2, 8-1 and 8-2
respectively against which the trigger lever strikes when it is
actuated. The hammer lever 3 is pivoted on the axis 4. Print drum
5, having characters on the surface thereof, is rotated at a speed
a predetermined ratio slower than that of ratchet wheel 1. The
timing lever 10 controls the engaging depth of the trigger lever
with the ratchet wheel. The plunger 11 operates according to the
print command signal.
Referring to FIGS. 5 and 6 for describing the operation, the
plunger 11 is energized and said lever rotates in the
counterclockwise direction when the print command enters. At this
moment, the trigger lever 2 is pushed by one end 10-1 of the timing
lever and rotates in the counterclockwise direction around the
contact point between tail 2-5 and the guide groove 8-3. Then the
contact portion 2-3 of the trigger lever enters in the locus of the
pawl of the ratchet wheel. The trigger lever is struck by the pawl
and displaces linearly in the direction of the arrow 12. At the
same time, the hammer lever 3 is struck by one end 2-4 of the
trigger lever and rotates around the axis 4. Said contact portion
2-3 and one end 2-4 of trigger lever 2 constitute the energy
transmitting portion of said trigger lever, said energy
transmitting portion defining the end of a neck projecting
laterally from the longitudinally extending body portion of the
trigger lever engaging trigger lever guides 8-3 and 8-6. The tail
2-5 of said body portion extends through the aperture 8-3 in
trigger lever guide 8 (see FIG. 9). The print hammer mounted on the
end of the hammer lever strikes the print drum 5, and printing is
performed. The trigger lever 2 strikes against the trigger lever
stopper 8-1 immediately before the hammer strikes gainst the print
drum and returns to its initial position. Without the trigger lever
stopper 8-1, the hammer lever would strike again against the
trigger lever during the return stroke to its initial position
after receiving the repulsive force from the drum. Thus, ghost
printing or double printing occurs, i.e., the same character or two
characters are printed on the same place on the paper. The trigger
lever stopper is provided to eliminate this defect. It is necessary
to place this trigger lever stopper carefully in order to prevent
the ghost printing or double printing, so that the trigger lever
does not enter again in the locus of the ratchet wheel immediately
after stroking against the trigger lever stopper 8-1.
On the other hand, when printing a symbol which does not occupy the
space of one character such as comma (,) or decimal point (.),
together with characters within the space of one character, e.g.,
"9," alpha-numeric characters and symbols and characters such as
comma and period are disposed in one column and by operating the
hammer twice, the character (9) and symbol (,) are printed within
one column, thus the printing time is shortened and high speed
printer is obtainable.
In prior art arrangements, characters 0 1 2 . . . 8 9 . . . and
symbols , and . are disposed on the print drum. For printing "9,",
"9" is printed in the first rotational cycle of the print drum, and
in the second cycle of rotation, "," is printed. Thus printing time
is prolonged due to the second cycle rotation of the print
drum.
Further, there is another method for printing "9,", wherein "9" is
printed in one column, "," is printed in the next column. In this
case printing time for two columns is necessary. Thus printing time
is wasted by one character. Besides the number of characters is
increased from 12 to 14. Therefore the size of the print drum is
increased and high speed printer cannot be obtained.
The present invention seeks to eliminate the above defects and to
provide a compact flying printer wherein the engaging portion of
the ratchet wheel with the trigger lever is out of the locus of the
ratchet wheel immediately after the ratchet wheel strikes against
the trigger lever, so that undesirable double striking is prevented
and the trigger lever is a little spaced from the trigger lever pin
when the trigger lever is biased by the timing lever, so that the
high speed printing can be performed precisely and
continuously.
Now, reference is made to the action of the trigger lever when the
print command signal is applied in and the trigger lever 2 is
struck by the ratchet wheel. At the moment when the trigger lever 2
is struck by the ratchet wheel 1, the center of gravity of the
trigger lever 2 is in such a position as shown by G in FIG. 7, and
the engaging portion 2-3 between said lever and the ratchet wheel
is above the center of gravity G, the trigger lever 2 displaces in
the direction of the arrow 12 rotating in the counterclockwise
direction.
Suppose that the distance from the center of gravity G to the
trigger lever portion which is struck by the tooth of the racchet
wheel is r and the distance from the center of gravity G to the
axis of rotation a (center of striking) is R, we obtain from the
equation of rotation when the rigid body is struck by the
impulse:
rR = k.sup.2 1
wherein
k= radius of rotation around the center of gravity of the trigger
lever.
Therefore at the moment when the trigger lever 2 is struck by the
ratchet wheel 1, the center of gravity of the trigger lever rotates
around a toward-the-inside direction of the locus of the tooth of
the ratchet wheel. However, rotation of the the trigger lever is
stopped by striking of the stopper face 2--2 of the guided portion
of the trigger lever against the stopper face 8-2 of the regulating
member 8 for the trigger lever and the trigger lever moves linearly
in the direction of the arrow 16 to operate the hammer lever 3. The
trigger lever stopper 8-1 is provided to prevent the double
striking of hammer in such a manner that the trigger lever strikes
against said stopper 8-1 immediately before the hammer strikes
against the drum. However, this arrangement is not sufficient
enough to prevent the double striking. After striking against the
trigger lever stopper 8-1, the trigger lever may again return
toward the inside of locus 14 of the pawl 1-1 of the ratchet wheel
and strike an undesirable character.
The arrangement according to the invention is so designed that by
placing the axis of rotation of the trigger lever properly
immediately after the trigger lever 2 strikes against the stopper
8-1, the engaging portion 2-3 between the trigger lever and the
ratchet wheel tooth is placed out of the locus of the pawl. Suppose
that the center of gravity of the trigger lever when the trigger
lever 2 strikes against the stopper 8-1 is G (FIG. 7), a distance
from G to the line of action 15 of the impact force caused when the
trigger lever strikes against the stopper 8-1 is l, and a distance
from the center of gravity G to the rotary axis of the trigger
lever after being struck by the ratchet wheel tooth is L, we
obtain:
Ll = k.sup.2 2.
If the striking between stopper or striking face point 2-1 of the
trigger lever and the stopper 8-1 is below the locus 16 of the
center of gravity of the trigger lever, the trigger lever 2
performs rotational movement toward the inside direction of the
ratchet wheel 1 so that the trigger lever is engaged firmly with
the tooth of the ratchet wheel. Therefore, it is required that the
impact point on stopper or striking face 2-1 be above the locus 16
of the center of gravity in order that the trigger lever comes out
of the locus of the pawl. On the other hand, double striking may
occur depending upon the position of the rotary center when the
trigger lever 2 strikes against the stopper 8-1.
As shown in FIG. 7, in the case where the locus 17 of one end 2-3
of the trigger lever intersects the locus 14 of the pawl 1-1 when
the trigger lever 2 strikes against the stopper 8-1, one end 2-3
enters in the locus of the pawl during rotation of the trigger
lever, so double striking may occur. It is clear that in the
situation as shown in FIG. 7, the locus 17 of one end 2-3 of the
trigger lever intersects with the locus 14 of the pawl. The axis of
rotation of the trigger lever is along the line 18 connecting said
intersecting point with the center point of the ratchet wheel. The
angle made by the line 18 and the locus 16 of the center of gravity
G is .phi.. If the rotary axis of the trigger lever is on point
(a') as shown by the solid line 19, one end 2-3 of the trigger
lever is surely out of the locus 14 of the ratchet wheel tooth.
At this time, the stopper or striking face 2-1, which is located on
the neck connecting the energy transmitting portion of the trigger
lever and the body portion thereof, is parallel to the line made by
the rotary center of the trigger lever and the center of gravity of
the trigger lever. The trigger lever struck by the ratchet wheel
moves along the motion line 16. It is so designed that the angle of
the stopper or striking face 2-1 of the trigger lever is:
90.degree. < .theta. < 180.degree.
In the arrangement according to the invention as shown in FIG. 5,
in order to ensure continuous printing, the regulating member 8-2
is spaced from the projection 2-2 on the trigger lever 2 when the
trigger lever is biased within the locus of the ratchet wheel 1 by
the timing lever 10. Without said space, the trigger lever 2
contacts with the guide member 8-2 when the timing lever 10
operates continuously. Therefore, precise continuous printing is
impossible as the trigger lever cannot return to the engaging
portion with the ratchet wheel 1 even after finishing printing due
to the friction loss between the guide member 8-2 and the
projection 2-2 of the trigger lever.
As described above, the printing method according to the invention
eliminates undesirable double striking in case of continuous
printing and to perform continuous printing precisely. Thus a
printer with high reliability and high printing speed can be
realized. Further, the print drum can be miniaturized which results
in compact high speed flying printer.
It is apparent that if the radius of rotational movement after the
trigger lever 2 strikes against the stopper 8-1 is smaller, it is
more suitable for a compact printer. Therefore it is necessary to
make the value of L small in the equation (2). k is a constant
which is fixed by the shape and material of the trigger lever.
Therefore, in order to reduce the value of L, it is necessary to
increase the value of l. Explaining this with reference to FIG. 8,
angle g is defined by line 90 and the locus 16 of the center of
gravity of the trigger lever. Since the line 20 connecting the
center of gravity G with the center of rotation a' defines a right
angle with the line of action 15 of the force, the locus of the
intersecting point between the two lines defining angle g defines
the arc 21 whose diameter is the line 90 connecting G with 2-1'.
Therefore, if the angle g becomes equal to zero the surface 2-1 of
the trigger lever is parallel with the line 90 connecting G with
the striking point 2-1', l becomes maximum, and accordingly the
radius of the rotation of the trigger lever attains minimum
value.
In the flying printer according to our invention, printing energy
is given by the continuously rotating ratchet wheel, so that the
speed of the trigger lever is constant when it is struck by the
tooth of the ratchet wheel. Therefore, the speed of the hammer
lever struck by the trigger lever is determined by the speed of the
ratchet wheel. In order to obtain sufficient printing energy, the
mass of the hammer lever must be large. However, in the compact
printer, it is required to reduce the size of the hammer lever. As
a result, the height of the hammer lever is increased and the
thickness of the hammer lever is the same with that of the hammer,
which results in compact printer. The hammer and the hammer lever
can be made from the same material. Thus the compact hammer body
can be produced without decreasing the mass. The hammer body,
consisting of the hammer and the hammer lever, can be manufactured
in a single process such as pressing out. This is very advantageous
for mass scale production.
The hammer 3 must precisely correspond to the character on the
print drum 5, which necessitates the use of a guide member for
guiding the hammer body. In the printer according to the invention,
a guide plate 102 for hammer lever is provided. Said guide plate
102 is provided with the guide groove or guide hole arranged in
zig-zag form as shown in FIG. 3-a to receive a projecting portion
106 of each hammer lever. This arrangement of the guide plate
reduces the size of the printer due to the fact that the hammer
body has uniform thickness.
The trigger lever 2 consists of a guide portion and a transmitting
portion. The guide portion in linear form comprises the projection
2-2 for displacing the trigger lever through linear motion. Said
guide portion moves slidably on the flat portion 8-2 of the trigger
lever regulating plate. Said transmitting portion projected from
said trigger lever engages with the ratchet wheel at 2-3 and
engages with the hammer lever at 2-4, and strikes against the
trigger lever stopper 8-1 at neck portion 2-1. As the shape of the
trigger lever is so constructed as above mentioned, its size is not
increased longitudinally. It is also very advantageous for easy
assembling as will be disclosed in the following. Unlike the
conventional trigger lever, the connecting point between the
transmitting portion and the trigger lever stopper forms one part
of the transmitting portion. As a result, the shape of the trigger
lever is simplified.
The regulating plate 8 regulates the motion of the trigger lever to
displace it toward the inside direction of the locus of the ratchet
wheel tooth when the trigger lever is struck by the ratchet wheel.
As shown in FIG. 9, the regulating plate 8 has guide hole 8-3 on
one end, and the trigger lever stopper 8-1 on the other end. This
construction makes it unnecessary to provide guide pins, and as a
result, the number of the parts required is reduced, construction
is simplified and assembly becomes easy.
In FIG. 10, one end 2-5 of the trigger lever 2 is projected from
the other surrounding parts. Since the guide portion of the trigger
lever is flat plate shaped, the guide hole of the regulating plate
8 is simple in its construction, so the trigger lever can be easily
removed and inserted for replacement by picking up one end 2-5
after completing the assembling of the printer. This enables easy
replacement and adjustment of the trigger lever after
assembling.
FIG. 11 shows means for mounting the power shaft 116 coaxial with
the ratchet wheel 1 on the main frames 101 and 101' of the printer.
The power shaft 116 is mounted on the main frames through the
bearings 117 and 117' in such a manner that the flange portions
117-1 and 117'-1 are on the outside of the main frames 101 and
101'. Since the diameter of the hole 172 provided on the main frame
is larger than that of the ratchet wheel 1, the ratchet wheel with
motor mechanism 105 can be easily assembled and reassembled after
completing the assembling. Generally, the cross sectional shape of
the ratchet wheel is asymmetrical, so undesirable vibration is
caused through the whole printer mechanism during high speed
rotation. Therefore, it is necessary to eliminate the unbalancing
of the printer including the motor and the ratchet wheel. In the
printer according to the invention, the fly wheel 171 for balancing
is mounted with the rotor of the motor. After eliminating the
unbalance between the motor with fly wheel and the ratchet wheel,
they are mounted as a unit. This construction is suitable for mass
scale production. As shown in FIGS. 2 and 3, the shaft of the paper
feeding roller 112 is inserted in the bearing through the opening
118 and 118' provided on the upper portion of the main frames 101
and 101'. So assembly and replacement of parts is very easy. It is
very advantageous for mass scale production.
The electromagnets 11 for operating the timing lever occupies a
relatively large space in the printer. As shown in FIG. 10, in the
printer according to this invention, the electromagnets are
symmetrically disposed with the center line of the printer.
Besides, as shown in FIG. 12, the electromagnets are mounted in
zig-zag form on the base member 190 of the electromagnets, so a
number of electromagnets are arranged in the narrow space.
FIG. 13 shows a detecting device of the printer according to the
invention which detects timing of the ratchet wheel and the print
drum. The detecting device consists of the illuminating
semiconductor 120, such as illuminating diode buried in the base
plate 121 and the semi-conductor 122 for detecting
photo-illumination mounted on the base plate 121'. Between the
semi-conductors 120 and 122', a shield plate 125 fixed on the
ratchet wheel shaft 116 is provided. In the conventional type of
the printer, such magnetic means as magnetic head is used for
detecting position of the character to be printed. As these
magnetic devices require large spaces, they cannot be incorporated
in the compact printer. The detecting means, according to the
invention, using the semi-conductor elements eliminates the above
defect. Said semi-conductor elements are mounted in the circuit
board.
FIGS. 25 and 26 show a simple embodiment according to this
invention for mounting the print drum on the main frames. This
embodiment answers the requirement from the user to change the
print drum for various character patterns. On the upper portion of
the main frame 101 of the printer, according to the invention,
inserting channel 400 is provided communicating between the edge of
the frame and hole 401. The outer periphery of the bearing 402 for
the shaft 403 of the print drum has flat planes 405 in parallel
with each other as shown in FIGS. 25 and 26 for inserting the
bearing 402 into the inserting channel 400. For mounting the print
drum on the main frame as shown in FIG. 25, sai flat plane 405 is
faced against the channel portion and bearing 402 is slid down
until it is inserted in the hole 401. Then as shown in FIG. 26, the
bearing 402 is rotated about 90.degree. from the inserting portion
400 of the main frame and L-shaped fitting plate 406 is fitted to
strengthen the fixing of the bearing on the frame. This
construction enables easy replacement of the print drum and the
paper feeding roller. It is very advantageous for mass scale
production. At the same time it is also very convenient for the
user.
Reference is now made to the attachment of the printer, such as
inked ribbon mechanism, color changing of ribbon and the driving
device for feeding the paper.
FIGS. 14, 15, 16 and 17 are views of the paper feeding mechanism
and ribbon feeding mechanism. 131 is a ratchet wheel for paper
feeding fixed on the paper feeding shaft 132. 135 is a paper
feeding roller made of rubber. Paper feeding ratchet lever 133 is
rotatably mounted on the paper feeding lever 136 by means of pin
134 said ratchet lever being biased in the clockwise direction
(FIG. 17) by spring 154. Said paper feeding lever 136 is biased
upward by the spring 153. Saw-toothed lever 137 provided with saw
teeth 137-1 is rotatably mounted on the paper feeding lever 136 by
means of the pin 138 and is biased in the counterclockwise
direction by the spring 139. Lever 143 cooperated with the
electromagnets for paper feeding is rotatably mounted on the paper
feeding lever 136 by means of the pin 145 and is biased in the
clockwise direction by the spring 139. Magnetic plate 144 facing to
the electromagnet 150 for feeding the paper is fixed on the lever
143. Wheel 146 is fixed coaxial with the print drum 152 and engages
with the saw teeth 137-1 of the saw-toothed lever 137. Said wheel
146 rotates in the certain reduction transmitted from the motor
axis 147 through the intermediate wheel 151. Ribbon feeding lever
148 is biased in the clockwise direction by the spring 149 and is
rotatably mounted on the axis 141.
FIG. 15 shows the position wherein paper and ribbon are advanced
and printing is completed. The wheel 146 mounted coaxially with the
print drum 152 disengages from the saw-toothed lever 137 which is
rotatably mounted on the paper feeding lever 136 by means of the
pin 138, as one end 143-1 of the lever 143 engages with the notch
137-3 of the lever 137. Energy is transmitted from the motor 147 of
the printer through the intermediate wheel 151 to the wheel 146
with certain reduction ratio to rotate the print drum
continuously.
FIG. 16 shows the condition of the paper feeding mechanism and
ribbon feeding mechanism when a signal is supplied to the
electromagnets. When the signal is supplied to the electromagnet
150, the magnetic plate 144 is actuated and the lever 143 connected
to the electromagnet rotates in the counterclockwise direction to
feed the paper. One end 143-1 of the lever 143 disengages from the
notch 137-3 of the lever 137 and the lever 137 rotates in the
counterclockwise direction by means of the spring 139. As a result,
the continuously rotating wheel 146 engages with the saw teeth
137-1. The paper feeding lever 136 is supplied energy for feeding
the paper from the wheel 146 through the lever 137 and the lever
137 displaces downwardly guided by the pins 141 and 142 and the
paper feeding shaft 132 to store the energy in the spring 153.
Through the motion of the paper feeding lever 136, the projection
136-1 of the paper feeding lever 136 engages with the ribbon
feeding lever 148 by its flat plane 148-2 and energy for feeding
the ribbon is stored in the spring 149. When the paper feeding
lever 136 is lowered to the predetermined position, the portion
137-2 of the lever 137 contacts the motor shaft 147. The lever 137
then rotates around the pin 138 in the clockwise direction and the
saw teeth 137-1 are disengaged from the wheel 146. The notch 137-3
of the lever 137 and one end 143-1 of the lever 143 are locked as
in the initial position by the force of the spring 139. The paper
feeding lever 136 returns to its initial position by the energy
stored in the spring 153.
The mechanism for winding and reversing the inked ribbon is pushed
by the flat portion 148-1 of the lever 148 by means of the energy
stored in the spring 149 and winds the inked ribbon and reverses
it.
Referring to FIG. 17 for describing the paper feeding mechanism,
the ratchet wheel 131 for feeding paper is rotated one pitch by the
lever 133 with pawl 133-1 to advance the paper by one line. To
advance the paper by exactly one line, the paper feeding mechanism
is designed in such a manner that the ratchet wheel 131 for feeding
the paper is locked in the normal rotating direction by the pawl
133-1 of the lever 133, the tooth of the ratchet wheel for paper
feeding, the flat portion 133-2 of the lever 133 and the shaft 132
for paper feeding. The paper feeding mechanism is thus designed to
prevent the paper feeding roller from rotating over one pitch due
to moment of inertia of the paper feeding roller. Further, rotation
of the paper feeding roller due to the force applied in the normal
rotational direction for printing is checked.
FIG. 18 is a perspective view showing ribbon shift mechanism
according to this invention for changing color of ribbon in
registration with the hammers by shifting the ribbon laterally. 136
is a paper feeding lever, 155 a ribbon guide lever, 156 a ribbon
shift lever, 157 a ribbon shaft lever spring, 158 an electromagnet
for ribbon shift, 160 a lever connected to a magnetic plate 159
facing to the electromagnet 158 for ribbon shift, 161 is a spring
connected to the lever 160, and 162 a bridge having the
intermediate wheel 151, the spring 157 and the spring 161 mounted
thereon.
Describing the operation of the inked ribbon of black and and red,
FIG. 19 shows the condition for printing in black color. The
electromagnet 158 is not energized, so printing is performed in
black without displacing the ribbon shift lever 156 and the ribbon
guide lever 156.
When the print command for red is not supplied to the
electromagnet, the notch 160-1 of the lever 160 of the
electromagnet engages with the notch 156-2 of the ribbon shift
lever 156, and the ribbon guide lever 155 does not operate.
Therefore, ribbon shift is not performed. For printing in red, as
shown in FIG. 20, the electromagnet 158 is energized by the print
command for red, and the magnetic plate 159 is actuated, and the
lever 160 of the electromagnet for ribbon shift is rotated
counterclockwise around the pin 163 to unlock the ribbon shift
lever 156. The lever 156 moves the ribbon guide lever 155 upward by
the force of the spring 157 and sets the red ribbon in printing
position.
When the paper feeding lever moves downward by connecting the wheel
146 with the saw-toothed lever 137 after completing printing in
red, the projection 136-2 of the paper feeding lever 136 is
connected to one end 156-1 of the ribbon shift lever, then the
ribbon guide lever 155 and the ribbon shift lever 156 move to their
original position. The notch 156-2 is locked again with the notch
160-1 of the lever 160. So the ribbon mechanism is in such a
condition wherein printing is not performed in red.
Referring to FIG. 17, this describes the relative movement between
the saw-toothed lever 137 and the wheel 146. When the saw-toothed
lever 137 connects with the wheel 146 and moves downwardly
substantially along the line of action 200, the rotary axis 138 of
the saw-toothed lever 137 lies on the right (in FIG. 17) side of
side line of action in the initial position. Accordingly, a moment
of force is applied to the toothed-lever in the counterclockwise
direction and the lever 137 rotates counterclockwise to connect the
lever 137 more firmly with the wheel 146.
As the lever 137 continues to lower downwardly, the rotary shaft
138 of the lever 137 approaches said line of action 200 until it
reaches to the right side of the line of action 200. At this
moment, the lever 137 receives a moment in the clockwise direction
from the wheel 146 and rotates clockwise. In our invention, the
saw-toothed lever 137 is pressed down until the flat portion 147-2
of the lever 137 strikes motor shaft 147.
The driving device for the paper feeding mechanism substantially
consists of the rotational body including ratchet wheel 146, a
transmission device including paper feeding lever 136 and the
saw-toothed lever 137, a first detent device including lever 143 of
the electromagnet and spring 139, a first trigger device including
electromagnet 150, a disconnecting device including motor shaft 147
and flat portion 137-2 of the saw-toothed lever, and first spring
member for paper feeding including the spring 153. For the purpose
of feeding the ribbon, a second lever 148 and spring 149 is
provided. For the purpose of shifting the ribbon, a second detent
device including shoulder 156-2 of the ribbon shift lever 156 and
the electromagnet 160, a second spring member 149, and a second
trigger device including the lever 158 is provided.
The foregoing structure is advantageous in that the energy for
winding and reversing the inked ribbon and changing the color of
inked ribbon and feeding the paper is supplied by the motor shaft
of the printer, and the trigger device is used only for triggering
of ribbon feeding, paper feeding and color changing of the inked
ribbon, therefore the electromagnet can operate on minimum electric
power. Thus, a driving device for paper feeding and ribbon feeding
suitable for compact printer can be obtained.
In the invention, the transmitting device, the disconnecting
device, and the first detent device are combined and mounted on one
lever and the driving device for feeding the paper and the inked
ribbon can be assembled as a unit independent from the printer
body, therefore making assembly easy.
According to the invention, the wheel for driving the print drum
also serves as a driving device for feeding paper and ribbon.
Further, the disconnecting device also partially serves as a motor
shaft of the printer. As a result, the number of parts required is
reduced and construction is simplified.
The rotational body for driving the paper feeding device and the
ribbon feeding device according to the invention are not directly
connected to the motor shaft of the printer but are connected to
the stepped down wheel of the motor shaft. Therefore, it is easy to
self-start even at overload. Thus a printer with high reliability
is obtainable.
The saw-toothed lever 137 according to the invention engages more
firmly with the wheel 146 at the beginning of engagement and in the
disengaging process it easily and surely disengages from the wheel
146 as the rotational force is applied to the saw-toothed lever in
such a direction as to accelerate the disengagement. Further, force
is not given excessively to the disengagement member 147, and wear
of the disengaging member 147 is reduced.
Reference is now made to the device for guiding the paper according
to the invention.
FIG. 21 is a side view of one embodiment of the flying printer
according to the invention. 5 is a print drum rotating
continuously. Character 202 is disposed on the periphery of the
print drum 5. Hammer 3 flies to the character on the print drum 5.
4 is a rotary shaft of the hammer, 205 a driving wheel for feeding
the pressure sensitive paper step by step. 112 is a paper feeding
roller pressed against said driving wheel through the paper. 207
and 208 are upper paper guide and lower paper guide respectively to
feed the paper between the hammer and the print drum 1. 209 is a
pressure sensitive paper, the thickness of which is d. A plurality
of print hammers are disposed in parallel corresponding to the
number of columns to be printed. Each hammer of the hammer body
detects the position of the desired character on the continuously
rotating print drum. When the character to be printed is placed in
position, each hammer body rotationally flies to perform printing.
During one rotation of the print drum 5, a whole one line is
printed on the paper 209.
Irregular printing as shown in FIG. 22 is caused due to the fact
that the position of the paper is shifted from the normal position
facing to the hammer 3 during one rotation of the print drum. This
irregular printing increases as the gap between the upper paper
guide 207 and the lower paper guide 208 is large compared with the
paper thickness d. The paper 209 may pass the course M or N between
the upper paper guide 207 and the lower paper guide 208, although
the paper is fed in the predetermined position by the paper feeding
wheel 205 and the paper feeding wheel to be driven 112.
Accordingly, printing may be performed when the paper 209 is in M
course at one time and N course at another time. As a result,
characters do not come on a uniform line. If the gap(s) between the
upper paper guide 207 and the lower paper guide 208 is equal to the
paper thickness d, this irregular printing will never occur.
However, if s < d, it is impossible to insert the paper in said
gap. It is very difficult to make the gap(s) a little larger than
the thickness (d) over the whole lengths of the paper guide in a
mass scale production.
The present invention intends to eliminate this irregular printing
by making the gap(s) nearly equal to the thickness (d).
Referring to one embodiment according to the invention, FIG. 23 is
a side view showing one embodiment and FIG. 24 is a partial cross
sectional view of FIG. 23. The projections 207a and 208a are
provided on the upper paper guide 207 and the lower paper guide 208
alternately as shown in FIG. 24. By making the gap (t) between the
projection 207a and 208a nearly equal to the paper thickness, said
irregular printing will be eliminated. In case of t < d or t
.ltoreq. 0 due to manufacturing error, the flexible paper can be
inserted in said gap and advanced smoothly. Thus it is easy to
apply mass scale production. Further, the paper can be advanced
smoothly even if the printer is subjected to the rapid change in
the environment temperature and the paper sticks to the paper guide
when the temperature approaches the dew point.
As described above, the present invention provides a high speed
flying printer with low electrical power consumption, which is
useful as an output device such as an electronic desk calculator or
cash register.
It will thus be seen that the objects set forth above, and those
made apparent from the preceding description, are efficiently
attained and, since certain changes may be made in the above
constructions without departing from the spirit and scope of the
invention, it is intended that all matter contained in the above
description or shown in the accompanying drawings shall be
interpreted as illustrative and not in a limiting sense.
It is also to be understood that the following claims are intended
to cover all of the generic and specific features of the invention
herein described, and all statements of the scope of the invention
which, as a matter of language, might be said to fall
therebetween.
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