Thermal transfer recording apparatus and facsimile apparatus utilizing the same

There is disclosed a thermal transfer recording apparatus in which the ratio of amount of transportation of ink sheet to that of recording sheet is varied according to a measured condition, for example head temperature, of the apparatus. When the temperature or humidity is higher, facilitating the ink transfer from the ink sheet, the ink sheet is advanced by a smaller amount to economize the consumption of the ink sheet.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a thermal transfer recording apparatus for 
image recording on a recording medium by transfer of ink from an ink 
sheet, and a facsimile apparatus utilizing such recording apparatus. 
2. Related Background Art 
In general the thermal transfer printer utilizes an ink sheet consisting of 
a substrate film coated with heat-fusible (or heat-sublimable) ink, and 
effects image recording by selectively heating said ink sheet with a 
thermal head according to an image signal, thereby transferring thus fused 
(or sublimed) ink onto a recording sheet. Since said ink sheet is 
generally so-called one-time ink sheet in which the ink is completely 
transferred to the recording sheet by a single image recording, it is 
necessary, after the image recording of a character or a line, to advance 
the ink sheet corresponding to the recorded length, thereby securely 
bringing an unused portion of the ink sheet to the next recording 
position. Consequently the amount of use of the ink sheet increases, and 
such thermal transfer printers tend to have a higher running cost in 
comparison with ordinary thermal printers utilizing thermosensitive 
recording paper. 
In order to solve the foregoing problem, there have already been proposed 
thermal transfer printers in which the recording sheet and the ink sheet 
are transported with different speeds, as disclosed in the Japanese 
Laid-open Patents Application No. 57-83471 and No. 58-201686 and in the 
Japanese Patent Publication No. 62-58917. 
Also for use in such thermal transfer printers, there is already known a 
multi-print ink sheet capable of plural (n) image recordings. In 
continuous image recording of a length L, such ink sheet allows to reduce 
the length thereof, transported during or after said image recording, to a 
value smaller than L (said value being L/n; n&gt;1). The efficiency of use of 
the ink sheet can therefore be increased to n times of the conventional 
efficiency, and a reduction in the running cost of the thermal transfer 
printer can be expected. Such recording method will hereinafter be called 
the multi printing method. 
In the conventional multi printing, however, the value n is determined 
independently from the temperature of thermal head, or the ambient 
temperature and humidity of the location where the apparatus is installed. 
In thermal transfer printers, a higher temperature of the thermal head or 
inside the thermal transfer printer facilitates the fusing of ink of the 
ink sheet, thereby facilitating the recording operation. Consequently the 
recording operation can be conducted with a larger value of n, namely with 
a smaller ratio of the amount of transportation of the ink sheet to that 
of the recording sheet. 
On the other hand, a lower temperature of the thermal head or inside the 
printer hinders the fusion of ink of the ink sheet, thus rendering the 
recording operation more difficult. Consequently, the recording operation 
has to be conducted with a smaller value of n, namely with a larger ratio 
of the amount of transportation of the ink sheet to that of the recording 
sheet. However the value n in the conventional printers has been selected 
independently from the temperature, so that the ink sheet has not been 
utilized efficiently. 
SUMMARY OF THE INVENTION 
In consideration of the. foregoing, an object of the present invention is 
to provide an improved thermal transfer recording apparatus and a 
facsimile apparatus utilizing such recording apparatus. 
Another object of the present invention is to provide a thermal transfer 
recording apparatus capable of saving the consumption of the ink sheet, 
and a facsimile apparatus utilizing such recording apparatus. 
Still another object of the present invention is to provide a thermal 
transfer recording apparatus capable of saving the consumption of the ink 
sheet and recording a satisfactory image by decreasing or increasing the 
amount of transportation of the ink sheet respectively under an easy or 
difficult condition for ink transfer, and a facsimile apparatus utilizing 
such recording apparatus. 
The foregoing and still other objects of the present invention will become 
fully apparent from the following description to be taken in conjunction 
with the attached drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Now the present invention will be clarified in detail by preferred 
embodiments thereof shown in the attached drawings. 
Facsimile apparatus (FIGS. 1 to 4) 
FIGS. 1 to 4 show a thermal transfer recording apparatus embodying the 
present invention and applied to a facsimile apparatus, wherein FIG. 1 is 
a block diagram showing electrical connections between a control unit 101 
and a recording unit 102 of the facsimile apparatus; FIG. 2 is a block 
diagram of the schematic structure of said facsimile apparatus; FIG. 3 is 
a lateral cross-sectional view of the facsimile apparatus; and FIG. 4 is a 
perspective view of a transport mechanism for a recording sheet 1 and an 
ink sheet 14 in the recording unit 102. 
At first reference is made to FIG. 2 for explaining the schematic structure 
of the facsimile apparatus constituting an embodiment of the present 
invention. 
A reader unit 100 for photoelectrically reading an original image and 
sending a digital image signal to a control unit 101, is provided with an 
original transporting motor and a CCD image sensor. The control unit 101 
is constructed in the following manner. A line memory 110, for storing 
image data of each line, serves to store the image data of a line from the 
reader unit 100 in case of the original transmitting or copying mode, or 
the received and decoded image data of a line in case of the image data 
receiving mode. The image formation is conducted by transferring thus 
stored data to the recording unit 102. An encoder/decoder unit 111 encodes 
the image information to be transmitted for example by MH encoding, and 
decodes the received encoded data into image data. A buffer memory 112 
stores image data which are to be transmitted or which have been received. 
These units of the control unit 101 are controlled by a CPU 113 composed 
for example of a microprocessor. The control unit 101 is further provided 
with a ROM 114 storing control programs of the CPU 113 and other various 
data, and a RAM 115 functioning as a work area for the CPU 113 and serving 
to temporarily store various data. 
A recording unit 102 is provided with a thermal line head and serves to 
record an image on the recording sheet by thermal transfer recording 
method. The details of said recording unit will be explained later with 
reference to FIG. 3. An operation console unit 103 is provided with 
various functional keys for example for starting the transmission, and 
telephone number input keys. A key 103a thereof, used for instructing the 
kind of the ink sheet used, indicates a multi-printing ink sheet or an 
ordinary ink sheet respectively when said switch 103a is on or off. There 
are also provided a display unit 104, usually positioned next to the 
operation console unit and used for displaying the state of various 
functions or of the apparatus; a power source unit 105 for supplying the 
entire apparatus with electric power; a modem (modulator/demodulator) 106; 
a network control unit (NCU) 107 for effecting an automatic call receiving 
operation by detecting the call tone and a line controlling operation; and 
a telephone unit 108. 
In the following there will be given a detailed explanation on the 
structure of the recording unit 102, with reference to FIG. 3, in which 
same components as those in the preceding drawings are represented by same 
numbers. 
Referring to FIG. 3, a sheet roll 10, composed of plain recording paper 11 
wound on a core 10a, is rotatably supported in the apparatus so as to feed 
the recording sheet 11 to a thermal head 13 by the rotation of a platen 
roller 12 in a direction indicated by an arrow. A sheet roll holding unit 
10b removably holds the sheet roll 10. The platen roller 12 serves to 
transport the recording sheet 11 in a direction b, and to press an ink 
sheet 14 and the recording sheet 11 toward heat-generating resistors 132 
of the thermal head 13. The recording sheet 11, which has been subjected 
to image recording by the heat generation of the thermal head 13, is 
transported toward discharge rollers 16 (16a, 16b) by further rotation of 
the platen roller 12, and, upon completion of image recording of a page, 
is cut into a page-sized sheet by mutual engagement of cutter members 15 
(15a, 15b). 
An ink sheet feeding roller 17 on which the ink sheet 14 is wound, and an 
ink sheet take-up roller 18 are driven by an ink sheet transport motor to 
be explained later, thereby taking up the ink sheet 14 in a direction a. 
Said ink sheet feeding roller 17 and ink sheet take-up roller 18 are 
detachably loaded in an ink sheet loading unit 70 in the main body of the 
apparatus. There are also provided a sensor 19 for detecting the remaining 
amount and the transport speed of the ink sheet 14; an ink sheet sensor 20 
for detecting presence or absence of the ink sheet 14; a spring 21 for 
pressing the thermal head 13 to the platen roller 12 across the recording 
sheet 11 and the ink sheet 14; and a recording sheet sensor 22 for 
detecting presence or absence of the recording sheet. 
In the following explained is the structure of the reader unit 100. 
A light source 30 illuminates an original 32. The light reflected by said 
original 32 passes through an optical system (mirrors 50, 51 and a lens 
52), enters a CCD sensor 31 and converted into electrical signals therein. 
The original 32 is transported with a speed corresponding to the reading 
speed of said original 32, by transport rollers 53, 54, 55, 56 driven by 
an unrepresented transport motor. An original stacker table 57 supports 
plural originals 32 which are separated one by one and advanced to the 
reader unit 100, through the operation of a transport roller 54 and a 
separating member 58. 
A control circuit board 41, constituting the principal part of the control 
unit 101, sends various control signals to various parts of the apparatus. 
There are also provided a power source unit 105 for supplying electric 
power to the various parts of the apparatus; a modem board unit 106; and 
an NCU board unit 107 for making connection with the external telephone 
lines. 
FIG. 4 shows the details of the transport mechanism for the ink sheet 14 
and the recording sheet 11. 
In FIG. 4 there are shown a recording sheet transport motor 24 for rotating 
the platen roller 12 thereby transporting the recording sheet 11 in a 
direction b opposite to the direction a; an ink sheet transport motor 25 
for transporting the ink sheet 14 in the direction a by means of a capstan 
roller 71 and a pinch roller 72; gears 26, 27 for transmitting the 
rotation of the recording sheet transport motor 24 to the platen roller 
12; gears 73, 74 for transmitting the rotation of the ink sheet transport 
motor 25 to the capstan roller 71; and a slip clutch unit 75. 
The ink sheet 14 advanced by the capstan roller 71 can be securely wound on 
the take-up roller 18, by selecting the ratio of the gears 74, 75 in such 
a manner that the length of the ink sheet wound on the take-up roller 18 
by the rotation of the gear 75a is larger than that transported by the 
capstan roller 71. The difference between the length of the ink sheet 14 
wound by the take-up roller 18 and that advanced by the capstan roller 71 
is absorbed by the slip clutch unit 75. It is thus made possible to 
prevent fluctuation in the transport speed (or amount) of the ink sheet 
14, resulting from change in the winding diameter of the take-up roller 
18. 
FIG. 1 shows the electric connections of the control unit 101 and the 
recording unit 102 of the facsimile apparatus of the present embodiment, 
wherein same components as those in other drawings are represented by same 
numbers. 
The thermal head 13, constructed as a line head, is provided with a shift 
register 130 for receiving serial recording data or shift clock signals 43 
of a line from the control unit 101, a latch circuit 131 for latching the 
data of the shift register 130 by a latch signal 44; and heat-generating 
resistors 132 of a line, which are divided into m blocks for driving, as 
illustrated by 132-l - 132-m. 
A temperature sensor 133 is mounted on the thermal head 13 for detecting 
the temperature thereof. An output signal 42 of said sensor 133 is A/D 
converted in the control unit 101 and supplied to the CPU 113, which thus 
detects the temperature of the thermal head 13 and regulates the energy 
supplied thereto according to the characteristics of the ink sheet 14, for 
example by varying the pulse duration of a strobe signal 47 or the driving 
voltage of the thermal head 13. A programmable timer 116 is set for the 
measurement of a time by the CPU 113, starts time measurement upon 
receiving a command therefor, and sends an interruption signal or a 
time-out signal to the CPU 113 after the lapse of each designated time. 
The characteristic or kind of the ink sheet 14 may be identified by the 
state of the switch 103a of the operation console unit 103 explained 
before, or by a mark printed on said ink sheet 14, or by a mark, a notch 
or a projection provided on the cartridge of the ink sheets. 
A drive circuit 46 receives drive signals for the thermal head 13 from the 
control unit 101, and releases strobe signals 47 for driving each block of 
the thermal head 13. Said drive circuit 46 is capable, in response to an 
instruction from the control unit 101, of varying the voltage supplied to 
a power supply line 45 for driving the heat-generating resistors 132 of 
the thermal head 13, thereby varying the energy supplied thereto. A drive 
circuit 36 for the cutter members 15 includes a cutter driving motor. A 
sheet discharge motor 39 drives the sheet discharge rollers 16. Drive 
circuits 35, 48, 49 are provided for respectively driving the sheet 
discharge motor 39, recording sheet transport motor 24 and ink sheet 
transport motor 25. These motors are composed of stepping motors in the 
present embodiment, but other motors, for example DC motors, may be 
employed for this purpose. 
Recording process (FIGS. 1-6) 
FIG. 5 is a flow chart of a recording sequence in the facsimile apparatus 
of the present embodiment, and a corresponding control program is stored 
in the ROM 114 of the control unit 101. This sequence is started when 
image data of a line are stored in the line memory 110 and become ready 
for image recording. It is assumed that the control unit 101 detects the 
loading of a multi ink sheet for example through the switch 103a. 
At first a step S1 transfers the recording data of a line to the shift 
register 130. Upon completion of transfer of the recording data of a line, 
a step S2 releases a latch signal 44 to store the recording data of a line 
in the latch circuit 131. Then a step S3 enters the temperature 
information from the temperature sensor 133, and stores the corresponding 
temperature value (t) in the RAM 115. 
Then, steps S4 and S5 discriminate the recording mode, and the sequence 
proceeds to a step S6, S31 or S41 respectively in case of a super fine 
mode, a fine mode or a standard mode. In the super fine mode, the step S6 
starts the transportation of the recording sheet 11 by a half step and 
sets the number l of repeated line recordings at "1". A half step advances 
the recording sheet by 1/15.4 mm, and the ink sheet by 
(1/15.4.times.1/5.times.1/5) mm. 
Then a step S7 discriminates whether the temperature t detected by the 
temperature sensor 133 exceeds 35.degree. C., and, if affirmative, the 
sequence proceeds to a step S8 to start the transportation of the ink 
sheet 14 by 4 half steps. If the temperature t does not exceed 35.degree. 
C. but exceeds 25.degree. C., the sequence proceeds from a step S9 to S10 
to start the transportation of the ink sheet 14 by 5 half steps. If the 
temperature t is equal to or less than 25.degree. C., the sequence 
proceeds to a step S11 to start the transportation of the ink sheet 14 by 
6 half steps. 
Then the sequence proceeds to a step S12 to energize one of the blocks of 
the heat generating resistors 132 of the thermal head 13. A step S13 then 
discriminates whether all the blocks of the heat generating resistors 132 
of the thermal head 13 have been energized, and, if not, the sequence 
proceeds to step S14-S16 to transfer the recording data of next line to 
the shift register 130 of the thermal head 13. When the energization of a 
block is completed in the step S16, the sequence returns to ,the step S12 
for energization of a next block. In the present embodiment, the thermal 
head 13 is driven in 4 blocks (m=4), so that the time required for 
recording of a line in the super fine mode is about 2.5 ms (600 
.mu.s.times.4 blocks). 
When the step S13 identifies the energization of all the blocks, indicating 
the completion of recording of a line, the sequence proceeds to a step S17 
to discriminate whether the recording of l lines, corresponding to 
respective recording mode, has been completed. If (lines have not been 
recorded, the sequence returns to the step S12 to start the transportation 
of the recording sheet 11 by a half step and the ink sheet 14 by 4-6 half 
steps, and to record a line with the same data. 
Upon completion of recording of l lines corresponding to respective 
recording mode, the sequence proceeds to a step S18 to discriminate 
whether the recording of a page has been completed. If not, steps S24-S27 
transfer the recording data of a next line to the thermal head 13, and 
effect auxiliary recording to the already recorded lines. Said auxiliary 
recording is conducted by energizing the heat generating resistors 132 of 
the thermal head 13 again with the already recorded data, with an 
energizing time of about 1/4 of that in the ordinary recording. 
When the step S18 identifies completion of image recording of a page, a 
step S19 advances the recording sheet 11 by a predetermined amount toward 
the discharge rollers 16 (16a, 16b), and a step S20 advances the ink sheet 
14 by (predetermined amount.times.1/20). The amount of transportation of 
the ink sheet in this step is smaller than that with respect to the amount 
of transportation of the recording sheet at the image recording. Then a 
step S21 activates the cutter members 15 (15a, 15b) to cut the recording 
sheet into a page size. The cut recording sheet 11 is discharged from the 
apparatus by the discharge rollers 16. Then a step S22 reverses the 
remaining recording sheet 11 by a length corresponding to the distance 
between the thermal head 13 and the cutter members 15 (predetermined 
amount-.alpha.). Also a step S23 reverses the ink sheet 14 by 
(predetermined amount-.alpha.).times.1/20, and the recording process of a 
page is thus terminated. Said value .alpha. is provided for preventing the 
separation of the recording sheet from the platen roller when the 
recording sheet is reversed. 
On the other hand, if the step S5 identifies the fine mode, the sequence 
proceeds to a step S31 to transport the recording sheet 11 by 2 half steps 
and to set the number l of repeated recordings at "2". Then a step S32 
discriminates whether the temperature t exceeds 35.degree. C., and, if 
affirmative, a step S33 advances the ink sheet 14 by 8 half steps. If the 
temperature t does not exceed 35.degree. C. but exceeds 25.degree. C., a 
step S34 advances the ink sheet 14 by 10 half steps. If the temperature is 
equal to or less than 25.degree. C., a step S36 advances the ink sheet 14 
by 12 half steps. Thereafter the sequence proceeds to the step S12 for 
energizing the thermal head 13. 
In case of the standard mode, the sequence proceeds to the step S5 to S41 
for advancing the recording sheet 11 by 4 half steps and setting the 
number l at "4". Then, if the temperature t exceeds 35.degree. C., the 
sequence proceeds to a step S42 to S43 to advance the ink sheet by 16 half 
steps. If the temperature t does not exceed 35.degree. C. but exceeds 
25.degree. C., a step S45 advances the ink sheet 14 by 20 half steps. If 
the temperature t is equal to or less than 25.degree. C., the sequence 
proceeds from a step S44 to S46 to advance the ink sheet 14 by 24 half 
steps, and the sequence thereafter proceeds to the step S12. 
FIG. 6 illustrates the above-explained relationship between the temperature 
t and the value n. 
When the temperature t exceeds 35.degree. C., the value n is selected 
larger (moving amount of the ink sheet 14 is selected smaller with respect 
to that of the recording sheet 11). In case of 35.degree. 
C..gtoreq.t&lt;25.degree. C. the value n is selected at a medium value, and, 
in case of 25.degree. C..gtoreq.t, the value n is selected smaller (moving 
amount of the ink sheet 14 is selected larger with respect to that of the 
recording sheet 11). 
FIG. 7 shows the moving distance of the recording sheet 11 per line in 
different recording modes. 
Taking the half step drive into consideration, the recording sheet 
transport motor 24 advances the recording sheet 11 by 1/15.4 mm in a half 
step. Said motor 24 is driven by a half step in a line of the super fine 
mode, or 2 half steps in a line of the fine mode, or 4 half steps in a 
line of the standard mode. 
FIG. 8 shows the number of steps required to transport the ink sheet 14 by 
a line in the different recording modes of the present embodiment. 
In the present embodiment, the ink sheet transport motor 25 advances the 
ink sheet 14 by {(1/15.4).times.1/5.times.1/5} mm in a half step. Thus, in 
the super fine mode, the motor 25 advances the ink sheet 14 by 4, 5 or 6 
half steps respectively for the large, medium or small value of n. 
Similarly, in the fine mode, the motor 25 advances the ink sheet 14 by 8, 
10 or 12 half steps respectively for the large, medium or small value of 
n. Also in the standard mode, the motor 25 advances the ink sheet 14 by 
16, 20 or 24 half steps respectively for the large, medium or small value 
of n. 
Consequently, for example in the super fine mode, the transportation ratio 
n of the recording sheet 11 to the ink sheet 14 is (5.times.5) 
.times.1/4=25/4 for a large value of n, or (5.times.5).times. 1/5=5 for a 
medium value of n, or (5.times.5).times.1/6=25/6 for a small value of n. 
The ink sheet 14 is transported by 4-6 half steps for every transportation 
of the recording sheet 11 by a half step. 
In the present embodiment, the transportation ratio n of the ink sheet 14 
and the recording sheet 11 is varied according to the temperature of the 
thermal head 13 as the temperature information, but the present invention 
is not limited to such embodiment. For example, the value n may be varied 
for example according to the ambient temperature of the location where the 
apparatus is installed. 
Also instead of variation of n according to the temperature information in 
the foregoing embodiment, it is possible to vary the value n for example 
according to the humidity. 
FIG. 9 shows such embodiment, in which the value n is selected large, 
medium or small respectively when the humidity h exceeds 70%, 70% 
.gtoreq.h&gt;50%, or 50%.gtoreq.h. 
Also the value n may be varied based on both temperature and humidity. 
Furthermore, in the foregoing embodiment, the value n is rendered variable 
by detecting the ambient condition such as temperature at the recording of 
each line, but it is also possible, for example, to record a page with a 
constant value n, and to vary said value n based on the measurement of 
ambient condition at the end of page. 
Recording principle (FIG. 10) 
FIG. 10 illustrates the state of image recording, employing a multi ink 
sheet in the thermal transfer printer of the present embodiment, with 
mutually opposite transporting directions for the recording sheet 11 and 
the ink sheet 14. 
The recording sheet 11 and the ink sheet 14 are pinched between the platen 
roller 12 and the thermal head 13, which is pressed to the platen roller 
12 under a predetermined pressure exerted by the spring 21. The recording 
sheet 11 is transported in a direction b with a speed V.sub.P, by the 
rotation of the platen roller 12, while the ink sheet 14 is transported in 
a direction a with a speed V.sub.I by the rotation of the ink sheet 
transport motor 25. 
When the heat generating resistors 132 of the thermal head 13 are energized 
by the power source 105, a hatched portion 81 of the ink sheet 14 is 
heated. The ink sheet 14 is composed of a substrate film 14a, and an ink 
layer 14b. The ink of thus heated ink layer 81 is fused, and a part 82 
thereof is transferred onto the recording sheet 11. The transferred ink 
layer portion 82 corresponds approximately to 1/n of the ink layer 81. 
Ink sheet (FIG. 11) 
FIG. 11 is a cross-sectional view of the ink sheet employed in the multi 
printing process of the present embodiment and composed of four layer in 
this case. 
A substrate film of the ink sheet 14 constitutes a second layer. In case of 
multi printing, as a same part of the ink sheet is subjected to thermal 
energy application plural times, said substrate is advantageously composed 
of an aromatic polyamide film or a condenser paper with a high thermal 
resistance, but a conventional polyester film may also be used for this 
purpose. The thickness is preferably as small as possible for improving 
the print quality, but is desirably in a range of 6-8 microns in 
consideration of the strength. 
A third layer is an ink layer containing ink in an amount enough for 
transfers of n times onto the recording sheet. Said ink layer is 
principally composed of a resinous adhesive such as EVA, a coloring 
material such as carbon black or nigrosin dye, and a binding material such 
as Carnauba wax or paraffin wax, so mixed as to enable the transfer of n 
times in a same place. The coating amount of said ink layer is generally 
in a range of 4-8 g/m.sup.2, but can be arbitrarily selected according to 
the desired sensitivity and density. 
A fourth layer is a top coating for preventing the transfer the third layer 
by pressure to the recording sheet in a non-printed area, and is composed 
for example of transparent wax. Thus the transfer by pressure takes place 
only in the fourth layer, and the recording sheet can be protected from 
the background smudge. A first layer is a heat resistant coating for 
protecting the substrate film of the second layer from the heat of the 
thermal head 13. Such top coating is preferably for the multi-printing ink 
sheet in which thermal energy of n lines may be applied to a same position 
(when black information continues), but the presence or absence of such 
top coating may be arbitrarily selected. Also such top coating is 
effective for a substrate film of a relatively low thermal resistance, 
such as a polyester film. 
The structure of the ink sheet 14 is not limited to the embodiment 
explained above, but may also be composed of a substrate layer and a 
porous ink holding layer containing ink therein and provided on a side of 
said substrate layer, or of a heat resistant ink layer consisting of a 
porous network structure formed on a substrate film and impregnated with 
ink. Also said substrate film may be composed, for example, of polyamide, 
polyethylene, polyester, polyvinyl chloride, triacetyl cellulose, nylon or 
paper. Also the heat resistant top coating, which is not necessarily 
indispensable, may be composed, for example, of silicon resin, epoxy 
resin, fluorinated resin or nitrocellulose. 
Also an ink sheet with heat-sublimable ink can be composed, for example, of 
a substrate film of polyethylene terephthalate, polyethylene naphthalate 
or aromatic polyamide, and a coloring material layer formed thereon and 
containing dyes and spacer particles formed from guanamine resin and 
fluorinated resin. 
Also the heating in the thermal transfer printer is not limited to the 
thermal head method explained above, but may also be achieved for example 
by direct current supply or by laser beam irradiation. 
Also the foregoing embodiments have been limited to the printers with a 
thermal line head, but the present invention is likewise applicable to the 
thermal transfer printers of so-called serial type. 
Also the recording medium is not limited to a recording paper but can be of 
any material capable of accepting ink transfer, such as cloth, or plastic 
sheet. Furthermore the ink sheet is not limited to the rolled structure 
shown in the foregoing embodiments, but can be of so-called ink sheet 
cassette structure, in which a casing incorporating ink sheet is 
detachably mounted in the main body of the apparatus. 
Furthermore, though the foregoing embodiments have been limited to 
facsimile apparatus, the present invention is not limited to such 
embodiments and is likewise applicable to a word processor, a typewriter, 
a copying machine or the like. 
Furthermore, the advancement of the ink sheet may be achieved by the 
winding operation of the take-up roller 18. 
As explained above, the foregoing embodiments reduces or increases the 
amount of transportation of the ink sheet with respect to that of the 
recording sheet respectively under an easy or difficult condition for 
fusion or sublimation of the ink sheet, thereby achieving effective use of 
the ink sheet and maintaining a constant recording density, thus improving 
the quality of recorded image. 
As explained in the foregoing, the present invention decreases the amount 
of transportation of the ink sheet under a condition where the ink of the 
ink sheet is easily transferred, thereby saving the consumption of the ink 
sheet, and increases said amount of transportation under a condition where 
the ink transfer is more difficult. Thus the present invention provides 
advantages of economizing the ink sheet and recording satisfactory images.