Stamp device with a printing element, movable ink supplying device, and plate making device employing an elongate heat sensitive stencil paper

A compact portable stamp device which can prevent the ink stains on an operator and his/her clothes and the occurrence of nonuniform printing and, further, simplifies the operation of changing the color of the ink. The stamp device comprises a heat sensitive stencil paper fed between first and second rollers. The heat sensitive stencil paper has a laminate structure including a thermoplastic film layer and a porous carrier layer. The stamp device has a stencil paper feeding unit for drawing the heat sensitive stencil paper from the first roller and winding the heat sensitive stencil paper around the second roller, and elastic ink impregnated member, provided in the feed path of the heat sensitive stencil paper between the first and second rollers, and a moving unit for moving the ink impregnated member between a first position where the ink impregnated member is separate from the heat sensitive stencil paper and a second position where the ink impregnating member is in close contact with the heat sensitive stencil paper. The ink impregnating member is brought into close contact witht the heat sensitive stencil paper to exude ink from the ink impregnated member through a perforated portion of the thermoplastic film thereby transferring an image onto a printing paper.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to a stamp device employing an elongated heat 
sensitive stencil paper capable of being perforated by heat and, more 
particularly, to a compact portable stamp device which records a stamp 
image on a medium with an ink through the elongated heat sensitive stencil 
paper previously perforated by heat using a thermal head. 
2. Description of the Prior Art 
There is known a compact portable stamp device employing a stencil paper 
having a perforation pattern formed of characters, figures, and/or symbols 
that are drawn using a pencil or a ball-point pen. Such a stamp device, as 
disclosed in U.S. Pat. No. 3,799,053 (Japanese Examined Patent Publication 
No. 54-9523), for example, includes a table and an inking unit. In this 
stamp device, the inking unit is mounted to reciprocate relative to the 
table and the stencil paper is mounted on the inking unit. When the inking 
unit is positioned at one end of a reciprocating stroke, mimeograph 
printing is carried out, and when the inking unit is positioned at the 
other end of the surface, the stamp device is accommodated in the table. 
However, in the stamp device disclosed in U.S. Pat. No. 3,799,053, when 
exchanging the stencil paper, the operator's hands or clothes are often 
stained by the ink. Further, the ink cannot be replaced by another ink 
having a different color. 
Also known is a heat sensitive stencil paper which can be perforated by 
infrared irradiation or heat of a thermal head to form a pattern of 
characters or the like. In particular, a typical example of such a heat 
sensitive stencil paper is formed by bonding a thermoplastic film and a 
porous thin paper to each other with use of an adhesive. A compact 
portable stamp device employing such a heat sensitive stencil paper is 
disclosed in Japanese Utility Model Laid-open Publication No. 63-11855, 
for example. In this stamp device, a mimeograph printing plate is 
detachably attached to a base including a grip portion, a cushion layer, 
and a cohesive layer. The mimeograph printing plate has a three-layer 
structure consisting of a perforated stencil paper, a frame, and a cover 
sheet having an ink impermeability. Ink is applied or placed in a space 
between the stencil paper and the cover sheet by the frame. In this stamp 
device, mimeograph printing can be effected by attaching the mimeograph 
printing plate having a perforated pattern of desired characters, figures, 
and/or symbols to the base and pressing the mimeograph printing plate 
against a printing paper. 
In the stamp device disclosed in Japanese Utility Model Laid-open 
Publication No. 63-11855, the operator's hands or clothes are less likely 
to be stained with ink as compared with the former prior art. However, the 
ink must be manually applied potentially causing the ink layer thickness 
to be nonuniform. As a result, nonuniformity of print occurs. 
SUMMARY OF THE INVENTION 
The invention addresses and solves the above problems. Thus, it is an 
object of the invention to provide a compact portable stamp device which 
can prevent stains by the ink and the occurrence of nonuniformity of print 
and to simplify the operation of changing the ink color. 
Another object of the invention is to provide a compact portable stamp 
device which records a stamp image on a medium with an ink through a 
previously perforated elongated heat sensitive stencil paper. 
A further object of the invention is to provide a compact portable stamp 
device which records a stamp image on a medium with an ink through an 
elongated heat sensitive stencil paper previously perforated by heat of a 
thermal head. 
The stamp device employing a heat sensitive stencil paper which has a 
pattern of pores formed by application of heat, comprising: 
an elongated heat sensitive stencil paper having an end wound around a 
first roller and a lead end for winding around a second roller; 
stencil paper feeding unit for drawing the heat sensitive stencil paper 
from the first roller and feeding the heat sensitive stencil paper to the 
second roller, the stencil paper feeding unit for feeding the pattern of 
pores of the heat sensitive stencil paper to a position between the first 
and second rollers; 
an ink supplying unit for supplying an ink to the pattern of pores of the 
heat sensitive stencil paper, the ink supplying unit being provided in a 
feeding path of the heat sensitive stencil paper between the first and the 
second rollers; and 
a moving unit for moving the ink supplying unit between a first position 
where the ink supplying unit is separated from the heat sensitive stencil 
paper and a second position where the ink supplying unit is in close 
contact with the pattern of pores of the heat sensitive stencil paper. 
In the stamp device having the above structure, when the pattern of pores 
of the heat sensitive stencil paper, produced where the heat is applied by 
the thermal head, is fed to a position between the first roller and the 
second roller, the ink supply unit is disposed in the first position where 
it is separated from the heat sensitive stencil paper. Then, the ink 
supplying unit is moved to the second position by the moving unit so as to 
be pressed against the heat sensitive stencil paper. As a result, the ink 
in the ink supply unit penetrates the pores of the thermoplastic film to 
transfer the pattern image onto the printing paper. 
Therefore, it is unnecessary for an operator to apply ink and the 
operator's hands or clothes are not stained by the ink. Furthermore, as 
the ink impregnating member is elastic, uniform printing can be effected 
even if a printing surface is uneven. Additionally, color change of the 
ink can be simply carried out in the first position where the ink 
impregnated supplying member is separate from the stencil paper and can be 
easily replaced.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Preferred embodiments of the invention will now be described with reference 
to the drawings. 
FIG. 1 is a vertical sectional view of a printing element of a stamp device 
according to the preferred embodiment, showing the ink impregnating member 
in a first position where it is separate from the heat sensitive stencil 
paper. The printing element is generally constructed so that a heat 
sensitive stencil paper (which will be hereinafter referred simply to as a 
stencil paper) 3 rolled at both its ends, is accommodated in a housing 1. 
The right end of the stencil paper 3, as viewed in FIG. 1, is wound around 
a supply spool 5 which functions as a first roller and the left end of the 
stencil paper 3 is wound around a take-up spool 7 which functions as a 
second roller. The supply spool and the take-up spool 7 are rotatably 
supported to the housing 1. 
As shown in FIG. 3, the stencil paper 3 has a laminate structure formed by 
bonding a thermoplastic film 9 and a porous carrier 13 to each other using 
an adhesive layer 11. In this preferred embodiment, the thermoplastic film 
9 is formed from a polyethylene terephthalate film (which will be 
hereinafter referred to simply as a PET film) having a thickness of about 
2 microns. However, the film may be made of any suitable thermoplastic 
material such as polypropylene or vinylidene chloride-vinyl chloride 
copolymer. The thickness of the PET film is preferably in the range of 1 
to 4 microns. If the thickness is less than 1 micron, the manufacturing 
cost becomes high and the strength becomes low, resulting in no 
significant practical use. In contrast, if the thickness is more than 4 
microns, it is too thick to perforate the film with a thermal head having 
a rated power of about 1 millijoule per dot. 
The porous carrier 13 in this preferred embodiment is formed from a porous 
thin sheet of paper made primarily of a natural fiber such as Manila hemp, 
kozo or mitzumata; a synthetic fiber such as PET, polyvinyl alcohol or 
polyacrylonitrile; or a semisynthetic fiber such as rayon. The thickness 
of the porous carrier 13 is about 40 microns and is preferably in the 
range of 20 to 100 microns. The stencil paper 3 having the above structure 
is wound in such a manner that the thermoplastic film 9 is directed to the 
outside of the housing 1 as viewed in FIG. 1. 
A feeding path of the stencil paper 3 is described with reference to FIG. 
1. The stencil paper 3 is drawn from the supply spool 5 and is fed to a 
cylindrical boss 15 integrally formed with the housing 1. A leaf spring 
19, having a felt 17 at one end thereof, is provided above the cylindrical 
boss 15. The leaf spring 19 is bent at its other end to form an L-shaped 
portion which is supported to the housing 1. The leaf spring 19 is 
normally elastically deformed so that the felt 17 provided at the one end 
of the leaf spring 19 normally presses the cylindrical boss 15 through the 
stencil paper 3 passing therebetween. The felt 17 and the leaf spring 19 
function as tension applying member. Accordingly, a predetermined 
frictional force is normally applied to the stencil paper 3 passing 
between the felt 17 and the cylindrical boss 15. 
The stencil paper 3, drawn between the felt 17 and the cylindrical boss 15, 
is fed to the take-up spool 7 through a paper guide which is formed by a 
platen 21, a guide roller 23, and a guide roller 25 and is wound around 
the take-up spool 7. A torsion coil spring 27 is wound at its one end 
portion around the take-up spool 7 and an arm portion formed at the other 
end of the torsion coil spring 27 is engaged with a shaft 29 integrally 
formed with the housing I. The torsion coil spring 27 is wound around the 
take-up spool 7 in such a manner that the torsion coil spring 27 is 
slackened in association with clockwise rotation of the take-up spool 7, 
as viewed in FIG. 1, while being tightened in association with 
counterclockwise rotation of the take-up spool 7. Accordingly, when the 
take-up spool 7 is rotated in a winding direction of the stencil paper 3 
(clockwise direction), the load applied to the take-up spool 7 by the 
torsion coil spring 27 is small, while when the take-up spool 7 is rotated 
in an unwinding direction of the stencil paper 3 (counterclockwise 
direction), the load applied to the take-up spool 7 by the torsion coil 
spring 27 is very large. 
The platen 21 is rotatably supported to the housing 1. A platen driving 
gear 22 is mounted on one end of the platen 21, so that a driving torque 
is transmitted through the platen driving gear 22 to the platen 21. A 
cylindrical guide 31 is integrally formed with the housing 1, at an upper 
middle portion of the housing 1, and extends both upwardly and downwardly 
from the upper middle portion thereof along the vertical direction (as 
viewed in FIG. 1). A grip unit 32 which functions as a moving means, is 
vertically slidably inserted in the cylindrical guide 31. One portion of 
the cylindrical guide 31 has an opening, as shown in FIG. 2, that is 
engaged by a first arm 73 of a latch 69 described below. 
As shown in FIG. 4, the grip unit 32 comprises a grip portion 33, a 
cylindrical member 35 for being engaged with the grip portion 33, and a 
compression coil spring 41 which is disposed between the cylindrical 
member 35 and the grip portion 33 along the vertical direction. The grip 
portion 33 is formed in a stepped shape along the vertical direction such 
that a diameter thereof is stepwise reduced toward its lower end portion 
which is inserted into the cylindrical member 35. The lower end of the 
grip portion 33 is circumferentially divided to form a plurality of tongue 
portions. Four of the tongue portions are provided with outwardly 
projecting pawls 37, respectively. The cylindrical member 35 is provided 
with four axially elongated holes 39 adapted to respectively engage the 
four pawls 37 of the grip portion 33. Accordingly, when the grip portion 
33 is inserted into the cylindrical member 35, the four pawls 37 of the 
grip portion 33 are brought into engagement with the four holes 39 of the 
cylindrical member 36, respectively. 
The cylindrical member 35 is provided at its lower end portion with a 
flange 38 and an external thread portion 40 below the flange 38. The 
compression coil spring 41 is interposed between the grip portion 33 and 
the cylindrical member 35, so as to generate an upward biasing force 
against the grip portion 33 to move the upper part of the grip portion 33 
away from where its lower part enters the cylindrical member 35. The 
biasing force of the compression coil spring is set to a value such that 
the pawls 37 are not deformed by creep deformation. Therefore, there is no 
possibility that the grip portion 33 totally separates from the 
cylindrical member 35. 
In the grip unit 32 having the above described structure, relative rotation 
of the grip portion 33 and the cylindrical member 35 around the vertical 
direction is inhibited, and relative axial movement of the grip portion 33 
and the cylindrical member 35 along the vertical direction is permitted 
because of the engagements between the pawls 37 of the grip portion 33 and 
the holes 39. That is, the grip portion 33 and the cylindrical member 35 
can be relatively axially moved by a given stroke corresponding to an 
axial gap between each pawl 37 and the respective hole 39 engaging 
therewith by depressing the grip portion 33 and the cylindrical member 35 
against the biasing force of the compression coil spring 41. As shown in 
FIG. 1, another compression coil spring 43 is provided between the grip 
unit 32 and the housing 1 so that the grip unit 32 is normally upwardly 
biased by the compression coil spring 43. 
An ink pad unit 45, which functions as ink supplying unit, is provided 
under the grip unit 32 such that the ink pad unit 45 is coupled to the 
cylindrical member 35 of the grip unit 32. As shown in FIG. 5, the ink pad 
unit 45 comprises an ink pad cartridge 47, an ink pad holder 49 mounted in 
the ink pad cartridge 47, an ink pad 51, as an ink impregnating member, 
bonded to the ink pad holder 49, and a leaf spring 53 mounted on the ink 
pad holder 49 for pressing the ink pad holder 49 upwardly. The ink pad 51 
is formed of a porous elastic material capable of holding the ink. An 
upper surface of the ink pad 51 is fixedly bonded to the ink pad holder 49 
by an adhesive. 
The ink pad holder 49 is formed in a box-like shape. An upper surface of 
the ink pad holder 49 is integrally formed with an internal thread portion 
55 adapted to engage with the external thread portion 40 of the 
cylindrical member 35. The upper surface of the ink pad holder 49 is 
further integrally formed with two pawls 57. The ink pad cartridge 47 is 
also formed in a box-like shape. An upper surface of the ink pad cartridge 
47 is formed with a rectangular through hole 48. An internal size of the 
ink pad cartridge 47 is so set as to just accommodate the ink pad holder 
49. The leaf spring 53 is formed in a substantially H-shaped configuration 
and is provided at its central portion with a through hole 59 for 
receiving the internal thread portion 55 of the ink pad holder 49 and is 
provided with two recesses 61 for respectively engaging the two pawls 57 
of the ink pad holder 49. The leaf spring 53 has four arms 63. A length of 
the leaf spring 53 extending in the direction of the four arms 63 is set 
to be larger than that of the through hole 48 of the ink pad cartridge 47 
in a longitudinal direction thereof. The central portion of the leaf 
spring 53 is mounted on the ink pad holder 49 by engaging the two recesses 
61 of the leaf spring 53 with the two pawls 57 of the ink pad holder 49, 
and the four arms 63 of the leaf spring 53 resiliently abut against the 
upper surface of the ink pad cartridge 47. Accordingly, the upper surface 
of the ink pad holder 49 is normally pressed against the ink pad cartridge 
47 by the spring force of the leaf spring 53, so that the ink pad 51 is 
normally received in the ink pad cartridge 47 so as not to project out of 
the ink pad cartridge 47 (see FIG. 1). 
As shown in FIG. 2, a side wall of the housing I is formed with an opening 
65 through which the ink pad unit 45 is to be inserted into the housing 1. 
When the ink pad unit 45 is inserted in the housing 1, the ink pad 
cartridge 47 is guided by guide grooves 67 so as to be held in a fixed 
position in the housing 1. Further, the internal thread portion 55 of the 
ink pad holder 49 is detachably engaged with the external thread portion 
40 of the cylindrical member 35. Accordingly, the ink pad holder 49 is 
vertically movable in the ink pad cartridge 47 in association with 
vertical movement of the grip unit 32. 
As shown in FIG. 2, a latch 69 is provided in the housing 1. The latch 69 
is rotatably supported to a shaft 71 integrally formed with the housing 1. 
The latch 69 has three arms, that is, a first arm 73 abutting against the 
cylindrical member 35 through opening in the cylindrical guide 31, a 
second arm 75 engaged with one end of a tension coil spring 79, and a 
third arm 77 abutting against a button key 81. 
The first arm 73 and the opening in the cylindrical guide 31 function as 
retaining means for retaining ink pad unit 45 in the second position where 
the ink pad 51 is in close contact with the stencil paper 3, and the 
button key 81 functions as a releasing means for releasing the first arm 
73 of the latch 69 from the opening in the cylindrical guide 31 as 
described below. 
The other end of the tension coil spring 79 is connected to the housing 1 
so that the latch 69 is normally biased in a counterclockwise direction, 
as viewed in FIG. 2, by the spring force of the tension coil spring 79. 
The button key 81 is axially slidably supported to a guide groove 83 
integrally formed with the housing A compression coil spring 85 is 
interposed between a flange portion formed at one end of the button key 81 
and the housing 1, so that the flange portion of the button key 81 is 
biased by the spring force of the compression coil spring 85 to abut 
against the third arm 77 of the latch 69. The spring force of the tension 
coil spring 79 is larger than the spring force of the compression coil 
spring 85, with the result that the first arm 73 of the latch 69 is 
normally kept in resilient abutment against an outer circumference of the 
cylindrical member 35. 
A frame 84 for regulating vertical movement of the ink pad unit 45 is 
provided below the ink pad unit 45. The frame 84 is fixed to the housing 1 
in such a manner that a side peripheral portion of the frame 84 is mounted 
to a lower end portion of the housing 1. The frame 84 has a central 
aperture 88 that is smaller than that of the ink pad 51. 
A plate making device 86 of the stamp device, for making a pattern of pores 
by the application of heat to the stencil paper 3, mounted in the printing 
element, is shown in FIG. 6. Desired characters, figures and/or symbols of 
pores are formed in the stencil paper 3 passing between the plate making 
device 86 and the stamp device as described below. As shown in FIG. 6, the 
plate making device 86 comprises an input section 87 for inputting data of 
the desired characters, figures and/or symbols and a release lever 96 for 
selecting one of a set position and a release position between the plate 
making device 86 and the stamp device, a liquid crystal display 91 having 
a predetermined number of columns on an upper face, for displaying the 
data input by the input section 87, and a plate making section 89 for 
receiving the printing element and making the pattern of pores formed by 
application of heat to the stencil paper 3. 
In the input section 87, characters and symbols are marked on the upper 
surface of the character selecting dial in a circumferential arrangement. 
For example, a mark indicating a desired character is set at a 
predetermined position by turning the character selecting dial. The plate 
making device 86 has recessed portion for detachably holding the printing 
element. 
The thermal head 93, as a heating means, is disposed at a position, 
confronting the platen 21 in the printing element, in the recessed 
portion, and a stencil paper feeding gear 95 is disposed at a position 
confronting the platen driving gear 22 of the printing element. A side 
wall of the recessed portion in the plate making section 89 is provided 
with a take-up spool driving cam 97. As shown in FIG. 1, the thermal head 
93 and the stencil paper feeding gear 95 are adapted to move into contact 
with or away from the platen 21 and the platen driving gear 22 of the 
printing-element, respectively, in association with the selection of 
either a set position or a release position of the release lever 96. 
Referring to FIG. 18, the thermal head 93 has a plurality of heating 
elements 42 which are arranged in a row 36 along the direction 
perpendicular to the stencil paper feed direction. The number of the 
heating elements 2 is 448 with, in this embodiment, eight thermal elements 
per millimeter. The heating elements 42 are driven selectively in 
synchronism with the feed of the stencil paper 3 to form pores in the 
stencil paper 3 by thermal punching according to input data input by the 
input section 87 (FIG. 6). 
In FIG. 1, a contact position of the thermal head 93 and the stencil paper 
feeding gear 95 with respect to the platen 21 and the platen driving gear 
22 is shown by a solid line, while a separate position is shown by a 
phantom line. The take-up spool driving cam 97 is adapted to engage with 
the take-up spool 7. When the thermal head 93 comes into contact with the 
platen 21 with the stencil paper 3 passing therebetween, a current is 
supplied to the thermal head 3 to thermally perforate the thermoplastic 
film 9 of the stencil paper 3. Both the stencil paper feeding gear 95 and 
the take-up spool driving cam 97 are adapted to be driven by a stencil 
paper feed motor 34. The stencil paper feeding gear 95 is adapted to mesh 
with the platen driving gear 22 to feed the stencil paper 3 by a 
predetermined distance. The take-up spool driving cam 97 is adapted to 
apply to the take-up spool 7 a winding torque for winding the stencil 
paper 3 fed by the platen driving gear 22. 
Electrical control of the plate making device 86 for making a pattern of 
pores formed by heating application of the thermal head 93 on the stencil 
paper 3 and feeding the stencil paper 3 is carried out by a control 
section included in the frame and shown in FIG. 19. The control section is 
connected to the input section 87 through an input interface 58 of a 
microcomputer 50, the latter functioning as a control means. The input 
interface 58 is connected by a bus 60 to a CPU 62 for controlling the 
stamp device, a ROM 64 for storing a control program, as shown in FIG. 19, 
a RAM 66 that functions as a storage means, a thermal punching character 
generator 68 (hereinafter referred to as "thermal punching CG-ROM") for 
generating characters for thermal punching by the thermal head 93, a 
display character generator 82 (hereinafter referred to as "display 
CG-ROM") for generating characters for the display 91, and an output 
interface 80. 
The ROM 64 has a program memory 70 for storing programs to control the 
operation of the stamp device, and a dictionary memory 72 for kana-kanji 
or other appropriate conversions. The RAM 66 has counters (not shown) in 
addition to an input buffer 76, a thermal punching buffer 74 and a shift 
register 78. 
The thermal punching CG-ROM 68 generates a dot pattern for thermal printing 
on the basis of input character code data. The display CG-ROM 82 generates 
a dot pattern to be displayed on the display 91 on the basis of input 
character code data. 
A thermal head driving circuit 90, a motor driving circuit 92 and a display 
driving circuit 94 are connected to the output interface 80. The thermal 
head 93, the stencil paper feed motor 34 and the display 91 are connected 
respectively to the thermal head driving circuit 90, the motor driving 
circuit 92 and the display driving circuit 94. 
FIG. 20 shows the thermal head driving circuit 90. One of the electrodes of 
each of the heating elements 42 is connected to a power feed terminal 100 
connected to the positive terminal of a 12 volt power supply. The other 
electrode of the power supply is connected to a ground of a driver 102. 
The output terminal of an inverter 106 has an input terminal connected to 
a thermal punching strobe input terminal 104 and the output terminal of a 
data latch circuit 110 has an input terminal which is connected to a latch 
signal input terminal 108. The other input terminal of the thermal 
punching drivers 102 are connected to an associated data latch circuit 
110. The input terminal of each data latch circuit 110 is connected to the 
output terminal of a shift register 116 having input terminals connected 
respectively to a data input terminal 112 and a clock input terminal 114. 
The control section orders that print data representing characters to be 
printed as stored in the shift registers 116 in synchronism with a clock 
signal. Upon the reception of a latch signal by the data latch circuits 
110, the print data stored in the shift registers 116 are applied to and 
stored in the corresponding data latch circuits 110 and, at the same time, 
the same print data are applied to the thermal punching drivers 102. In 
this state, if a thermal punching pulse signal in the 0 state is applied 
to the input terminal through the thermal punching strobe input terminal 
104, a signal in the 1 state is output at the output terminal of the 
inverter 106 connected to the input terminals of the thermal punching 
drivers 102. Accordingly, the output terminal of the thermal punching 
drivers 102 are in the 0 state when the data provided by the data latch 
circuits 110 are in the 1 state and, consequently, a driving current is 
supplied through the power feed terminal 100 to the corresponding heating 
elements 42. The pulse width of the thermal punching pulse signal applied 
to the thermal punching strobe input terminal 104 is determined so that 
the heating elements 42 are heated to a surface temperature suitable for 
thermal punching, for example, a temperature greater than 200.degree. C. 
A stamping stencil producing program executed by the control section of the 
stamp device will be described with reference to FIG. 21. 
Upon connection of the stamp device to a power supply, the buffers and the 
register of the RAM 66 are initialized in step S1. Thermal punching data 
entered by operating the input section 87 is stored in the input buffer 76 
in steps S2, S3 and S4, and then characters corresponding to the thermal 
punching data are read from the display CG-ROM 82 and are displayed on the 
display 91 in step S5. When produce stencil is selected using the input 
section, step S7 is executed after steps S2 and S6 to develop a dot 
pattern, generated by the thermal punching CG-ROM 68, in the thermal 
punching buffer 74. Subsequently, dot lines of the dot pattern are 
transferred one dot line at a time to the shift register 116 and pores 
corresponding to the dot lines are formed in the stencil paper 3 in step 
S8. A query is made in step S9 to see if all the pores corresponding to 
the thermal punching data have been formed. If the response in step S9 is 
negative, steps S8 and S9 are repeated. Thus, the dot pattern is formed in 
the stencil paper by the row 36 of the 448 heating elements 42. If produce 
stencil has not been selected in step S6, then the control section 
determines whether another action, such as stencil paper advance, has been 
input using the input section 87. If so, the process is executed. The 
stamping device thus executes the stamping stencil producing program to 
form the desired character string on the stencil paper 3. 
The control section is disclosed in U.S. patent application Ser. No. 
07/811,974, concurrently filed Dec. 23, 1991, to TAKASHI MIKI AND TETSUJI 
FUWA and entitled "STAMP DEVICE EMPLOYING A HEAT SENSITIVE STENCIL PAPER 
TO BE PERFORATED BY HEAT OF A THERMAL HEAD", the disclosure of which is 
incorporated herein by reference. 
The operation of the stamp device as constructed above will now be 
described. As previously mentioned, FIG. 1 shows a first position of the 
printing element where the ink pad 51 is separated from the stencil paper 
3, and the printing element is mounted to the plate making device 86. 
(shown in part). In this condition, the thermal head 93 is in pressure 
contact with the platen 21, through the stencil paper 3, and the stencil 
paper feeding gear 95 is in mesh with the platen driving gear 97. 
First, print information is input from the input section 87 of the plate 
making device 86, and a print start command is finally input. In response 
to the print start command, the stencil paper feeding motor is driven to 
rotate. A torque of the motor is transmitted through the stencil paper 
feeding gear 95 to the platen driving gear 22, thereby rotating the platen 
21 in the clockwise direction as viewed in FIG. 1. Since the stencil paper 
3 is sandwiched, under pressure, between the platen 21 and the thermal 
head 93, the stencil paper 3 is fed by a frictional force between the 
thermal head 93 and the platen 21. At this time, a back tension is applied 
to the stencil paper 3 in a direction reverse to a feeding direction 
thereof by a frictional force between the stencil sheet 3 and the felt 17. 
The thermal head 93 is controlled to be electrically heated at a 
predetermined timing according to the print information by a control 
section, as discussed above, in the plate making device 86, so that 
portions (dots) of the thermoplastic film 9 of the stencil paper 3 are 
melted by the heat of the thermal head 93, thereby forming a predetermined 
perforation image on the stencil paper 3. The stencil paper 3 fed from the 
platen 21 is wound around the take-up spool 7 by a winding torque 
transmitted through the take-up driving cam 97 to the take-up spool 7. 
This winding torque is generated by a known slip mechanism (not shown) 
interposed between the stencil paper feeding motor and the take-up spool 
driving cam 97. Accordingly, the stencil paper 3 is wound around the 
take-up spool 7 by an amount equal to a feeding amount generated by the 
platen 21. After the predetermined perforation image is formed on the 
stencil paper 3 by the heat of the thermal head 93, a perforation image 
formed area of the stencil paper 3 is fed to a position centered on the 
aperture 88 of the frame 84. 
After the plate making in the stamp device is completed, the grip portion 
33 of the printing element is depressed downwardly to move the ink pad 51 
to a second position where the ink pad 51 closely contacts the stencil 
paper 3 as shown in FIGS. 7 and 8. More specifically, when the grip 
portion 33 is depressed downwardly against the spring force of the 
compression coil spring 43, the cylindrical member 35, guided by the 
cylindrical guide 31 as shown in FIG. 2, is urged downwardly by the 
compression coil spring 41. Because the ink pad holder 49 is connected 
with the cylindrical member 35, by the engagement between the thread 
portions 40 and 55, the ink pad holder 49 is lowered by the lowering of 
the cylindrical member 35 counter to the spring force of the leaf spring 
53, as the ink pad holder 49 is guided by the side wall portion of the ink 
pad cartridge 47. In this manner, the ink pad 51 comes into close contact 
with the stencil paper 3. 
Thereafter, when the cylindrical member 35 is further lowered from the 
position establishing contact between the ink pad 51 and the stencil paper 
3, a peripheral portion of the ink pad 51 comes into contact with the 
frame 84 through the stencil paper 3. When the cylindrical member 35 is 
further lowered from this position, the peripheral portion of the ink pad 
51 is compressed by the frame 84, and an upper end of the cylindrical 
member 35 reaches the first arm 73 of the latch 69. 
As a result, the latch 69 is rotated, by force from the tension coil spring 
79, in the counterclockwise direction, as viewed in FIG. 8, and the first 
arm 73 of the latch 69 is brought into engagement with the upper end of 
the cylindrical member 35. The spring force of the tension coil spring 79 
is larger than the sum of the spring force of the compression coil spring 
43 acting to lift the cylindrical member 35 and the spring force of the 
leaf spring 53 acting to lift the ink pad holder 49. Therefore, the latch 
69 is securely engaged with the upper end of the cylindrical member 35 
rather than being forced back by the compression coil spring 43 and the 
leaf spring 3. The first arm 73 of the latch 69 and the upper end of the 
cylindrical member 35 function as a retaining means for retaining contact 
between the ink pad 51 and the stencil paper 3. In this condition, a 
peripheral portion of the perforation image formed area of the stencil 
paper is pressed between the frame 84 and the ink pad 51. Therefore, the 
stencil paper 3 is substantially prevented from slipping between the frame 
84 and the ink pad 51. The above-mentioned operation is carried out while 
the printing element is mounted on the plate making device 86. 
Then, the release lever 96, shown in FIG. 6, is moved to the release 
position to thereby separate the thermal head 93 and the stencil paper 
feeding gear 95 from the platen 21 and the platen driving gear 22, 
respectively, so that the printing element may be removed from the plate 
making device 86. Thereafter, as shown in FIG. 9, the printing element is 
placed at a desired printing position such that the perforation image 
formed area of the stencil paper 3 is opposed to the desired printing 
position on the printing paper 98. In this position, when the grip portion 
33 is further depressed, the compression coil spring 41 in the cylindrical 
member 35 is compressed, and the ink pad 51 contacting the printing paper 
98 through the stencil paper 3 is accordingly elastically deformed by the 
spring force of the compression coil spring 41 according to a compression 
quality thereof. When the grip portion 33 is further depressed from this 
position, an inside upper end of the grip portion 33 comes into abutment 
against an upper end of the cylindrical guide 31 of the housing 1 with the 
result that further depression of the grip portion 33 is prevented. 
In the above position, the ink pad 51 is elastically deformed by a 
predetermined amount according to the spring force of the compression coil 
spring 41. Accordingly, the ink held in the ink pad 51 is forced therefrom 
in an amount corresponding to an elastic deformation amount of the ink pad 
51 to pass through the perforated portion of the stencil paper 3 onto the 
printing paper 98. Thus, a transferred image on the printing paper 98 is 
obtained that corresponds to the perforated image formed on the stencil 
paper 3. 
At this time, the grip portion 33 is in contact with the upper end of the 
cylindrical guide 31 of the housing Therefore, any further depression 
force applied to the grip portion 33 is merely transferred through the 
housing 1 and the frame 84 to the printing paper 98. That is, excessive 
elastic deformation of the ink pad 51 beyond the predetermined quantity is 
prevented. Accordingly, it is possible to prevent a deterioration in print 
quality due to excessive ink being forced from the ink pad 51. Further, as 
the ink pad 51 is formed of an elastic material, it can be readily 
deformed to follow any unevenness of the printing paper 98, thus 
preventing the occurrence of a local blur. Moreover, as the compression 
coil spring 41 is interposed between the grip portion 33 and the ink pad 
51, a uniform pressure can be applied to the printing paper 98. 
According to the stamp device described above, after a number of sheets of 
paper are printed using the same plate and it deteriorates, or a different 
pattern is desired, printing can be continued using a new plate. In this 
case, before mounting the printing element to the plate making device 86 
to make the new plate, the ink pad 51 is moved from the second position 
where the ink pad 51 is in close contact with the stencil paper 3 to the 
first position where the ink pad 51 is separated from the stencil paper 3. 
More specifically, referring to FIG. 8, the button key 81 is depressed 
against the spring force of the tension coil spring 79 to thereby rotate 
the latch 69 in the clockwise direction and disengage the latch 69 from 
the upper end of the cylindrical member 35. 
As a result, the ink pad holder 49 is lifted by the spring forces of the 
compression coil spring 43 and the leaf spring 53 until the upper surface 
of the ink pad holder 49 comes into abutment against the lower surface of 
the ink pad cartridge 47. In this manner, the depression of the button key 
81 causes the ink pad 51 to move to the first position where the ink pad 
51 is separated from the stencil paper 3. Then, the printing element is 
mounted to the plate making device 86 with the release lever 96 of the 
plate making device 86 in the release position. Then, the release lever 96 
is moved to the set position, thereby making ready the plate making device 
86 to make a new plate described above. 
According to the stamp device described above, color change and 
replenishment of the ink can be easily carried out by exchanging the ink 
pad unit 45. Such an exchange will be described with reference to FIGS. 1 
and 10. 
Referring to FIG. 1, the grip portion 33 is first rotated in the 
counterclockwise direction to disengage the external thread portion 40 of 
the cylindrical member 35 from the internal thread portion 55 of the ink 
pad holder 49. As a result, the grip unit 32 is lifted by the spring force 
of the compression coil spring 43 to upwardly move the cylindrical member 
35 until an upper surface of the flange 38 comes into abutment against a 
lower end of the cylindrical guide 31 of the housing 1. This position is 
shown in FIG. 10. As shown in FIG. 10, the ink pad unit 45, which has been 
separated from the grip unit 32, can be drawn leftwardly through the 
opening 65 of the housing 1. Thus, the ink pad unit 45 can be removed. 
Further, installation of the ink pad unit 45 is carried out in the reverse 
order to that of the removal. 
As discussed above, with the stamp device of this preferred embodiment, the 
ink pad unit 45 can be exchanged very simply so that operator's hands or 
clothes are not stained by the ink during a change in the color of the ink 
or a replenishment of the ink. 
It should be noted that the invention is not limited to the above preferred 
embodiment, but may be embodied in various modes without departing from 
the scope of the invention. For instance, while the second position of the 
ink pad 51 tightly contacting the stencil paper 3 is maintained by the 
engagement of the latch 69 with the cylindrical member 35, and printing is 
effected by further depressing the grip portion 33 in the above preferred 
embodiment, the latch 69 may be removed, and the printing may be effected 
when the ink pad 51 is moved to the second position where the ink pad 51 
tightly contacts the stencil paper 3. 
A second embodiment will be described in reference to FIGS. 11 and 12. 
The main difference between the first embodiment and the second embodiment 
is the mechanical structure of the plate making device 86 of the first 
embodiment has been modified. In particular, a latch release bar 99 is 
provided, on the side wall of the plate making device 86 of the second 
embodiment, for releasing the button key 81. Therefore common elements 
between the first embodiment and the second embodiment are designated by 
the same reference numbers and labels and the detailed explanation 
relating to the common elements will be omitted. 
As shown in FIG. 11, the release bar 99, which functions as a retention 
releasing means, is provided at an engaging position, opposing the 
releasing button key 81 when the stamp device is mounted on the plate 
making device 86 on the side wall of the plate making device 86. 
According to the stamp device, after a plurality of sheets of paper are 
printed using the same plate, printing can then be carried out using a new 
plate. 
In this case, in the first embodiment, before mounting the printing element 
to the plate making device 86 to make the new plate, the ink pad 51 must 
be moved from the second position where the ink pad 51 is in close contact 
with the stencil paper 3 to the first position where the ink pad 51 is 
separated from the stencil paper 3. To do so, the button key 81 is 
depressed, against the spring force of the tension coil spring 79, to 
thereby rotate the latch 69 in the clockwise direction and disengage the 
latch 69 from the upper end of the cylindrical member 35. 
As a result, the ink pad holder 49 is lifted by the spring forces of the 
compression coil spring 43 and the leaf spring 53 until the upper surface 
of the ink pad holder 49 comes into abutment against the lower surface of 
the ink pad cartridge 47. In this manner, the depression of the button key 
81 causes the ink pad 51 to move to the first position where the ink pad 
51 is separate from the stencil paper 3. 
However, with the second embodiment, if the operator erroneously fails to 
depress the button key 81 before mounting the printing element to the 
plate making device 86, the latch release bar 99, in the plate making 
device 86, depresses the button key 81 upon mounting the printing element 
so that the ink pad 51 is reliably moved to the second position where the 
ink pad 51 is separate from the stencil paper 3. 
In both embodiments, the printing element is mounted to the plate making 
device 86 with the release lever 96 of the plate making device 86 in the 
release position. Then, the release lever 96 is moved to the set position, 
thereby obtaining the ready condition of the plate making device 86 as 
discussed above. At this time, the new plate is made in the stamp device 
by using the plate making device 86. Accordingly, there is no possibility, 
in the second embodiment, that the stencil paper 3 is fed under the 
condition where it remains in close contact with the ink pad 51 thereby 
avoiding problems such as a defective feed or breakage of the stencil 
paper 3. 
A third embodiment will be described in reference to FIGS. 13-17. 
The main difference between the first embodiment and the third embodiment 
is in the regulating member for regulating amount of vertical movement of 
the grip unit 32 as shown in FIG. 15. The common elements between the 
first embodiment and the third embodiment are designated by the same 
reference numbers and labels and a detailed explanation relating to the 
common elements is omitted. 
In the first embodiment, the frame 84 is fixed to the housing 1 in such a 
manner that a side peripheral portion of the frame 84 is mounted to a 
lower end portion of the housing 1. However, the frame 84 is not fixed to 
the housing 1 in the third embodiment. Rather, the movement limit for the 
grip unit 32 is provided by making an inner end surface 186 of the grip 33 
abut against an upper end surface 184 of the cylindrical guide 31 of the 
housing 1, so that the grip unit 32 is not permitted to move beyond a 
predetermined point. 
The ink pad 51 is further moved from a second position where the ink pad 5 
is in close contact with the stencil paper 3 to a third position where the 
ink pad 51 is pressed under a predetermined pressure against the recording 
medium 98 through the stencil paper 3. At this time, the movement of the 
ink pad 51 is limited at the third position by both the upper end surface 
184 of the cylindrical guide 31 and the inner end surface 186 of the grip 
33 which function as the limiting means. Thus, the ink pad 51 is 
compressed by a predetermined amount when in the third position. 
Accordingly, ink in the ink pad 51 is forced therefrom to penetrate the 
perforated portion of the thermoplastic film of the stencil paper 3 to 
produce a transferred image on the recording medium 98 corresponding to 
the perforation image formed in the stencil paper 3. The grip 33 is not 
permitted to move downwardly beyond a predetermined point by the abutment 
of the grip 33 against the upper end surface 184 of the cylindrical guide 
31 of the housing 1. That is, excessive compression of the ink pad 51 
beyond a predetermined point is prohibited. Accordingly, there is no 
possibility that excessive ink is squeezed from the ink pad 51 to thereby 
cause a deterioration in the print quality. 
Although the invention has been described in its preferred forms with a 
certain degree of particularity, obviously many changes and variations are 
possible therein. It is therefore to be understood that the invention may 
be practiced otherwise than as specifically described herein without 
departing from the scope and spirit of the invention.