Thermal recording films and method of thermal image recording using the same

The improved thermal recording film includes a clear film base, a thermal recording layer formed on one side of the film base and a matted layer formed on the other side of the film base. The improved method of thermal image recording using a thermal recording film having a thermal recording layer on one side of a clear film base, preferably the improved thermal recording film described above includes the steps of processing the image to be recorded in such a way that the correct image will come out when viewed from the side opposite to the thermal recording layer, and recording the thus processed image on the thermal recording layer in the thermal recording film. The improved thermal recording film and the method of thermal image recording permit the recorded image to be viewed without being affected by abrasions and other defects formed on the image recording surface due to sliding contact with the thermal head, and yet allow for appropriate adjustment of the luster on the image viewing surface, to thereby enable the image to be viewed under more advantageous conditions.

BACKGROUND OF THE INVENTION 
This invention relates to the art of thermal recording films for use in 
thermal image recording and a method of the thermal image recording using 
said films. 
Thermal recording film in which a thermal recording layer is formed on the 
film base as a support is commonly used to record the images produced in 
diagnosis by ultrasonic scanning. This recording method, commonly referred 
to as thermal image recording, eliminates the need for wet processing and 
offers several advantages including convenience in handling. Hence, the 
use of the thermal image recording system is not limited to small-scale 
applications such as diagnosis by ultrasonic scanning and an extension to 
those areas of medical diagnoses such as MRI and X-ray photography where 
large and high-quality images are required, is under review. 
As is well known, thermal image recording involves the use of a thermal 
head having a glaze in which heating elements for heating a thermal 
recording film to record an image are arranged in one direction and, with 
the glaze in contact with the thermal recording film (thermal recording 
layer), the two members are moved relative to each other in a direction 
perpendicular to the direction in which the heating elements are arranged, 
as the respective heating elements are heated imagewise in accordance with 
the image to be recorded to heat the thermal recording layer, thereby 
accomplishing image reproduction. 
Thus, in the process of thermal image recording, the thermal head in 
contact with the thermal film is moved relative to the latter such that 
the thermal recording layer is heated to effect image recording. In 
addition, it is not uncommon that the temperature of the thermal head (its 
glaze) becomes as high as 200.degree. C. and above even in the normal 
image recording mode. Therefore, many abrasions are formed on the thermal 
recording layer in the thermal film or sheet on account of sliding with 
the thermal head and, in an extreme case, such abrasions can interfere 
with the correct viewing of image. 
As a further problem, the luster of the thermal recording layer and, hence, 
the image recording surface cannot be adjusted appropriately and the 
uncontrolled luster of the image recording surface can be another cause of 
interference with the correct viewing of image. 
Such abrasion and unnecessary luster not only result in the deterioration 
of the quality of finished images; they can also cause a serious problem 
in medical areas by leading to a wrong diagnosis. 
SUMMARY OF THE INVENTION 
The present invention has been accomplished under these circumstances and 
has as an object, providing a thermal recording film that permits the 
recorded image to be viewed without being affected by abrasions and other 
defects formed on the image recording surface due to sliding contact with 
the thermal head and which yet allows for appropriate adjustment of the 
luster on the image viewing surface, and thereby enables the image to be 
viewed in a more advantageous manner. 
Another object of the invention is to provide a method of performing 
thermal image recording using said thermal recording film. 
In order to attain the object described above, the first aspect of the 
present invention provides a thermal recording film comprising a clear 
film base, a thermal recording layer formed on one side of the film base, 
and a matted layer formed on the other side of the film base. 
In order to attain another object described above, the second aspect of the 
invention provides a method of thermal image recording using a thermal 
recording film having a thermal recording layer on one side of a clear 
film base, the method comprising the steps of processing the image to be 
recorded in such a way that the correct image will come out when viewed 
from the side opposite to the thermal recording layer, and recording the 
thus processed image on the thermal recording layer in the thermal 
recording film. 
Preferably, the thermal recording film is the one recited above.

DETAILED DESCRIPTION OF THE INVENTION 
The thermal recording film of the invention and the method of thermal image 
recording using the film will now be described in detail with reference to 
the preferred embodiment illustrated in the accompanying drawings. 
FIG. 1 shows schematically an embodiment of a thermal image recording 
apparatus that can implement the thermal image recording method of the 
invention using the thermal recording films of the invention. The thermal 
image recording apparatus generally indicated by 10 in FIG. 1 and which is 
hereunder simply referred to as a "recording apparatus" performs thermal 
image recording on thermal recording films of a given size, say, B4 
(namely, thermal recording films in the form of cut sheets, which are 
hereunder referred to as "thermal films A"). The apparatus 10 comprises a 
loading section 14 where a magazine 24 containing thermal films A is 
loaded, a feed/transport section 16, a record/transport section 18, a 
recording section 20 performing thermal image recording on the thermal 
films A by means of the thermal head 66, and an ejecting section 22. 
The thermal head 66 is connected to processing means 80 which optionally 
performs image processing on the image to be recorded on the thermal film 
A such that it will come out correctly when it is viewed from the side 
opposite to the recording surface. 
FIG. 2 is a cross sectional view showing schematically the thermal film A 
of the invention. The thermal film A of the invention comprises a film 
base 90 typically made of clear film such as clear polyethylene 
terephthalate (PET), which is a support, a thermal recording layer 92 
formed on one side of the film base 90 and a matted layer 94 formed on the 
other side of the film base 90. 
The function of the matted layer 94 is to adjust the luster on the image 
viewing side of the thermal film A from which the user looks at the 
recorded image and it may be formed by applying a clear paint having fine 
particles dispersed therein and drying the applied coat. The matted layer 
94 provides fine asperities on the surface of the viewing side of the film 
base 90 such that the incident light will undergo random reflection. Thus, 
in the thermal film A of the invention, the surface on the side opposite 
the recording layer 92 is used as a viewing surface and it is rendered 
"dull" by a matting treatment. 
The method of forming the matted layer 94 is in no way limited to the 
example just described above and any known methods are applicable, such as 
a method in which a clear paint is applied to a surface of the film base 
90 and the applied coat is brought into intimate contact with a surface 
having an appropriate degree of roughness until the paint dries, and a 
method in which a surface of the film base 90 is directly processed to 
form fine asperities. 
The luster of the viewing surface can also be adjusted by controlling the 
surface state (surface roughness which determines the degree of random 
reflection of light) of the matted layer 94 by a suitable technique 
depending on the method by which it is formed. If the matted layer 94 is 
formed by applying a dispersion of fine particles, the luster of the 
viewing surface can be adjusted by controlling the quality of the 
dispersed fine particles. 
In the thermal film A of the illustrated case, the recording layer 92 is a 
thermal recording layer of the type that is formed on thermal recording 
materials such as ordinary thermal films. 
As in the case of ordinary thermal films, the thermal film A of the 
illustrated case is subjected to thermal recording as the thermal head 
urged against the recording layer 92 moves relative to the film A. 
Basically, image recording on the thermal film A is performed by the image 
recording method of the invention (which is hereunder referred to simply 
as the "recording method"), provided that a reversed image is recorded on 
the recording layer 92 such that it will come out correctly when viewed 
from the matted layer 94 on the side which is opposite the side where the 
recording layer 92 is formed, and the thus recorded image is viewed from 
the matted layer 94 (i.e., the viewing side). 
Thus, using the thermal film A and by applying the recording method of the 
invention, one can observe the recorded image without any adverse effects 
of the abrasions and other flaws on the recording surface 92 that have 
developed on account of sliding contact with the thermal head 66. 
Furthermore, in spite-of the fact that the (thermal) recording layer 92 
cannot usually be subjected to a matting treatment, the thermal film A 
which has a viewing surface on the side remote from the recording layer 92 
is provided with the matted layer 94 and this permits the recorded image 
to be viewed under appropriately controlled luster conditions. 
Typically, such thermal films A are stacked in a specified number, say, 100 
to form a bundle, which is either wrapped in a bag or bound with a band to 
provide a package. In the illustrated recording apparatus 10, the 
specified number of the thermal films A bundled together with the 
recording layer 92 facing down are accommodated within the magazine 24 in 
the recording apparatus 10 and the thermal film A is taken out of the 
magazine 24 one by one and submitted to the thermal image recording. 
The magazine 24 is an enclosure or a casing having a cover 26 freely opened 
and closed. The magazine 24 containing the thermal films A is loaded in 
the loading section 14 of the recording apparatus 10. The recording method 
of the invention may be applicable to the thermal films having no matted 
layer as well as the thermal films A of the invention having the matted 
layer 94. 
The loading section 14 has an inlet 30 formed in the housing 28 of the 
recording apparatus 10, a guide plate 32, guide rolls 34 and a stop member 
36; the magazine 24 is inserted into the recording apparatus 10 via the 
inlet 30 in such a way that the portion fitted with the cover 26 is coming 
first; thereafter, the magazine 24 as it is guided by the guide plate 32 
and the guide rolls 34 is pushed until it contacts the stop member 36, 
whereupon it is loaded at a specified position in the recording apparatus 
10. 
The feed/transport section 16 has the sheet feeding mechanism using the 
sucker 40 for grabbing the thermal film A by application of suction, 
transport means 42 and a transport guide 44; the thermal films A are taken 
out of the magazine 24 in the loading section 14 and transported to the 
record/transport section 18 which is located downstream in the direction 
of film transport. 
The transport means 42 is composed of a transport roller 46, a pulley 47a 
coaxial with the roller 46, a pulley 47b coupled to a rotating drive 
source, a tension pulley 47c, an endless belt 48 stretched between the 
three pulleys 47a, 47b and 47c, and a nip roller 50 that is to be pressed 
onto the transport roller 46. The forward end of the thermal film A which 
has been sheet-fed by means of the sucker 40 is pinched between the 
transport roller 46 and the nip roller 50 such that the film A is 
transported downstream. 
When a signal for the start of recording is issued, the cover 26 is opened 
by the OPEN/CLOSE mechanism (not shown) in the recording apparatus 10. 
Then, the sheet feeding mechanism using the sucker 40 picks up one sheet 
of thermal film A from the magazine 24 and feeds the forward end of the 
thermal film A to the transport means 42 (to the nip between rollers 46 
and 50). At the point of time when the thermal film A has been pinched 
between the transport roller 46 and the nip roller 50, the sucker 40 
releases the thermal film A and, the fed thermal film A is supplied by the 
transport means 42 into the record/transport section 18 as it is guided by 
the transport guide 44. At the point of time when the thermal film A to be 
used in recording has been completely ejected from the magazine 24, the 
OPEN/CLOSE mechanism closes the cover 26. 
The record/transport section 18 has a regulating roller pair 52, a 
transport roller pair 56 and a guide 58. The advancing end of the thermal 
film A first reaches the regulating roller pair 52. Therefore, the 
distance between the transport means 42 and the regulating roller pair 52 
which is defined by the transport guide 44 is set to be somewhat shorter 
than the length of the thermal film A in the direction of its transport. 
The regulating roller pair 52 are normally at rest. When the advancing end 
of the thermal film A reaches the regulating roller pair 52, the 
temperature of the thermal head 66 is checked and if it is at a specified 
level, the regulating roller pair 52 start to transport the thermal film 
A. Then, the thermal film A is guided by the guide 58 and transported to 
the recording section 20 by means of the regulating roller pair 52 and the 
transport roller pair 56. 
The recording section 20 has the thermal head 66, a platen roller 60, a 
guide 62 and a fan 76 for cooling the thermal head 66. The thermal head 66 
is capable of thermal recording at a recording (pixel) density of, say, 
about 300 dpi. The head comprises a glazed active device for performing 
thermal recording on the thermal films A and a heat sink fixed to the 
device. The thermal head 66 is supported on a support member 68 that can 
pivot about a fulcrum 68a either in the direction of arrow a or in the 
reverse direction. 
The platen roller 60 rotates at the preset speed of the image recording to 
transport the thermal film A in a direction perpendicular to the extending 
direction of the glaze as thermal film A is held in the specified 
position. As already mentioned, since the thermal films A are accommodated 
together with the recording layer 92 facing down within the magazine 24, 
the platen roller 60 in contact with the matted layer 94 of the thermal 
film A transports the thermal film A. 
Before the thermal film A is transported to the recording section 20, the 
support member 68 has pivoted to UP position (in the direction opposite to 
the direction of arrow a) so that the thermal head 66 (or its glaze) is 
not in contact with the platen roller 60. When the advancing end of the 
thermal film A being transported by the record/transport section 18 has 
reached the record START position (i.e., corresponding to the glaze of the 
thermal head 66), the support member 68 pivots in the direction of arrow a 
and the thermal film A becomes pinched between the thermal head 66 and the 
platen roller 60 with the glaze of the thermal head 66 in contact with the 
recording layer 92, and then the thermal film A is transported downstream 
as it is held in the specified position by means of the platen roller 60; 
in the meantime, the thermal head 66 which has the individual heating 
elements on the glaze for heating imagewise performs thermal recording of 
the original image on the thermal film A. 
In the illustrated recording apparatus 10 which can implement the recording 
method of the invention, the thermal head 66 is connected to means 80 
which processes the image to be recorded on the recording layer 92 such 
that the correct image will come out when viewed from the matted layer 94; 
more specifically, the thermal head 66 is connected to means 80 that 
reverses the image which is to be recorded by the thermal head 66. 
As already mentioned, the thermal film A has the transparent film base 90 
and is basically characterized in that the matted layer 94 on the side 
opposite the recording layer 92 is used as a viewing surface. On the other 
hand, the ordinary image reading apparatus R or the like supplies the 
thermal head 66 with image information that will produce an image which is 
to be viewed from the recording layer 92. Therefore, in the recording 
apparatus 10 for implementing the recording method of the invention, the 
image delivered from the image reader R or the like is reversed by the 
processing means 80, then fed to the thermal head 66 which records the 
reversed image on the recording layer 92. 
Thus, according to the recording method of the present invention, the 
recorded image can be viewed without being adversely affected by the 
abrasions that were formed on the recording layer 92 by the sliding action 
of the thermal head 66. The thermal film A has the added advantage of 
permitting the recorded image to be viewed under properly controlled 
luster conditions. 
The method in which the processing means 80 can employ for image reversing 
is not limited to any particular type and any known techniques of 
processing image information may be employed to transpose the recording 
pixels. In one example, the pixels in the image corresponding to the row 
of heating elements in the thermal head 66 (or its glaze surface) that 
have been delivered from the image reader R or the like may be transposed 
such that they are reversed right and left. More specifically, image 
reading from the memory or the like which is usually performed from the 
right to the viewing direction may be replaced by reading from the left. 
In addition, the processing means 80 is connected to means for switching 
the apparatus between two operational modes, one for effecting the 
reversing of image and the other for not performing the image reversing. 
If the latter mode is selected, the information on the image to be 
recorded that is delivered to the thermal head 66 from the image reader R 
or the like is directly used to perform normal thermal recording and 
produce an image for viewing from the recording layer 92. 
After the end of thermal image recording, the thermal film A as it is 
guided by the guide 62 is transported by the platen roller 60 and a 
transport roller pair 63 to be ejected into a tray 72 in the ejecting 
section 22. The tray 72 projects exterior to the recording apparatus 10 
via the outlet 74 formed in the housing 28 and the thermal film A carrying 
the recorded image is ejected via the outlet 74 for takeout by the 
operator. 
On the foregoing pages, the thermal recording films and the thermal image 
recording method of the invention have been described in detail but the 
present invention is in no way limited to the stated embodiments and 
various improvements and modifications can of course be made without 
departing from the spirit and scope of the invention. 
As described above in detail, the thermal recording film of the invention 
and the method of thermal image recording using said film have the 
advantage of permitting the recorded image to be viewed without being 
affected by abrasions and other defects formed on the image recording 
surface due to sliding contact with the thermal head and yet allowing for 
appropriate adjustment of the luster on the image viewing surface to 
thereby enable the image to be viewed under more advantageous conditions. 
This advantage is particularly significant in medical areas since errors 
in diagnosis due to difficulties in image viewing can be considerably 
reduced.