JPH054223B2 - - Google Patents

Description

[Detailed description of the invention] (Technical field) The present invention relates to a thermal transfer recording device.

(Prior art) A recording sheet such as paper is superimposed on the ink layer of an ink sheet, and both sheets are run against a thermal head, and the ink layer is removed from the back side of the ink sheet by the thermal head in accordance with an image signal. A thermal transfer recording method is known in which ink is positionally selectively heated and melted, and the heated and melted ink is transferred onto a recording sheet to obtain a recorded image on the recording sheet.

This type of thermal transfer recording method has excellent image quality, high recording speed, and extremely quiet recording, making it suitable for output printers such as computers and word processors, or facsimile machines. It is intended to be applied to the recording section of communication equipment, etc.

An ink sheet is an ink layer formed by heating and melting ink on a base sheet such as a thin resin film or condenser paper, coating the base sheet, and then cooling and solidifying at room temperature. The ink that makes up the ink layer is solidified at normal temperatures, so in this state,
Even if another object comes into contact with the ink layer, the ink will not adhere to this object. However, when the ink layer is heated, the ink melts and easily adheres to objects that come into contact with it.

Thermal melting of the ink by the thermal head is performed from the back side of the ink sheet, as described above. In other words, the ink in the ink layer is heated through the base sheet, and in order to increase recording speed and save energy required for recording, the base sheet is made thin and the ink is heated through the base sheet. It is preferred to increase heat transfer to the layer. Since the ink layer itself is extremely thin, this ultimately results in
The only solution is to reduce the thickness of the ink sheet itself. From this point of view, very thin ink sheets have recently come to be realized.

By the way, in conventionally known thermal transfer recording devices, it is troublesome to install the ink sheet into the recording device, and the ink sheet is often damaged during installation.
Wrinkles and the like often occur, which often causes recording failure. In addition, when a recording sheet is not conveyed properly or jammed, it is difficult to remove the recording sheet that has stagnated inside the device. There were also problems such as damage to the parts. A thermal transfer recording device is also known in which the upper and lower parts of the recording device can be opened and closed at different times with the ink sheet conveyance path facing each other in order to facilitate the installation and replacement of ink sheets (Japanese Unexamined Patent Application Publication No. 1989-1999). Publication No. 140270). It is true that replacing the ink sheet is easy if the top and bottom of the device can be opened and closed, but when replacing the ink sheet and closing the top and bottom of the device, the ink sheet inevitably becomes loose. ,
The occurrence of wrinkles on the ink sheet due to this slack cannot be avoided.

(Objective) Therefore, an object of the present invention is to provide a novel thermal transfer recording device that effectively solves such problems.

(composition) The present invention will be explained below.

The thermal transfer recording device of the present invention has the following features in terms of the structure of the invention.

That is, first, the upper part of the recording apparatus can be opened and closed in a hinge-like manner with the ink sheet conveyance path facing the lower part of the apparatus. The ink sheet is movably held at the top of the device.

Second, of a thermal head and a platen roller that clamp the ink sheet and the recording sheet in the recording section, the thermal head is provided at the upper part of the apparatus, and the platen roller is provided at a fixed position at the lower part of the apparatus. The platen roller is driven to rotate intermittently to move both sheets relative to the thermal head. Further, between the feeding side of the held ink sheet and the thermal head, there is provided a buffer guide means that comes into contact with the back side of the ink sheet and applies a buffering tension to the ink sheet, and this buffer guide means is also provided in the apparatus. installed at the top.

The reason why the upper part of the apparatus can be opened and closed in a hinge-like manner with the ink sheet conveyance path opposite to the lower part of the apparatus is because the ink sheet is installed in the thermal transfer recording apparatus.
This is to make replacement easy and reliable, and to facilitate the removal of recording sheets stagnant within the apparatus when a recording sheet conveyance failure occurs.

Furthermore, of the thermal head and the platen roller, the platen roller is provided at a fixed position at the bottom of the apparatus for the following reasons.

That is, the platen roller is driven to rotate intermittently to cause the ink sheet and the recording sheet to run relative to the thermal head. Therefore, extremely high precision is required for the intermittent rotation of the platen roller, and for this reason, the platen roller needs to be directly driven by a drive motor. If the platen roller is installed on the top of the device,
Inevitably, a drive motor must also be provided at the top of the device, and due to the weight of the drive motor, a large amount of force is required to open and close the top of the device. Therefore, in order to avoid such inconvenience, a platen roller is provided at the bottom of the apparatus. The meaning of providing the buffer guide means will be described later.

Hereinafter, description will be given based on specific examples.

FIG. 1 shows the appearance of an example of a thermal transfer recording device embodying the present invention.

FIG. 2 shows only the main parts necessary for explanation of the inside of this thermal transfer recording apparatus.

FIG. 3 shows a state in which the upper part of the thermal transfer recording apparatus is opened with respect to the lower part of the apparatus.

First, to explain the symbols appearing in FIG. 1, numeral 1 is the lid, numeral 2 is the main body, numeral 3 is the tray, numeral 4 is the cassette, and numeral 5 is the
The cover member and the symbol S each indicate a recording paper as a recording sheet.

The lid part 1 can be opened and closed with respect to the main body part 2.

Among the various parts of the apparatus, the part that is opened and closed together with the lid part 1 is the upper part of the apparatus, and the part that is fixed to the main body part 2 is the lower part of the apparatus. The tray 3 is removably attached to the lid part 1. The cassette 4 stores the recording sheets S in a stack therein, and is attached to the recording apparatus main body 2. Although plain paper is used as the recording paper S, it goes without saying that, for example, a resin film or the like can be used as the recording sheet if necessary. Recording paper S is
Various sizes can be used, and each size is stored in a dedicated cassette for use. Regardless of the dimensions of the recording paper S, the length of the recording paper in the direction perpendicular to the recording paper conveyance direction is referred to as the width of the recording paper, and the direction of the length is referred to as the width direction of the recording paper.
No matter what size recording paper is used,
The center portion in the width direction is always set with respect to the main body portion 2 in a fixed position. That is,
In this example of the apparatus, the recording paper is set by a so-called center sorting method.

The cassette 4 is provided with a magnetic pattern corresponding to the size of the stored recording paper at the engagement portion with the main body 2, and the main body 2 detects the magnetic pattern to detect the set recording paper. detects the dimensions of the thermal head and controls the drive area of the thermal head.

In addition to the recording paper stored in the cassette, this apparatus also allows other recording sheets to be manually loaded into the apparatus for recording. The lid member 5 is adapted to open and close the entrance of the recording sheet setting section for manual feeding.

Now, to explain each part of the apparatus with reference to FIG. 2, reference numeral 11 is a paper distribution roller, numeral 12 is a paper feed roller, numeral 13 is a return roller, numeral 14 is a guide, numerals 15 and 16 are guides, and numeral 17 is a Sensors 18A and 18B are registration rollers 19
2 shows a guide, and 20 shows a platen roller, respectively.

Further, code IS is an ink sheet, code 21 is a guide pipe, code 22 is a buffer guide, code 23 is a guide pipe, code 24 is a guide roller, code 2
5 is a thermal head, 26 is a bracket, 27 is a relay roller, 28 is a guide, and 29 is a peeling claw.

Furthermore, codes 30A, 30B, 32A, 32
B, 34A, 34B are discharge rollers, code 31A,
31B, 33A, and 33B are guides, 35 is a control unit, 36 is a power source, 37 is a cover, 38 is a sensor, 39 is a take-up spool, and 40 is a take-up shaft.

The paper distribution roller 11 has a shaft equipped with a plurality of rollers arranged at intervals in a skewer shape, and these rollers have a rubber surface and have sufficient frictional force against the recording paper S. . This paper distribution roller 11 rotates clockwise during operation.

The paper feed roller 12 and the return roller 13 are also equipped with a plurality of rollers arranged in a skewered manner on their shafts, and the surfaces of these rollers are made of rubber, and each has sufficient friction against the recording paper S. It has power. During operation, the paper feed roller 12 rotates clockwise, but the return roller 13 is rotated clockwise via a friction transmission mechanism.

The guide 14 is plate-shaped, and from the cassette 4,
It constitutes a conveyance path for recording paper leading to registration rollers 18A and 18B. The guides 15 and 16 are also plate-shaped and constitute a conveyance path for recording sheets that are manually set, that is, a manual conveyance path.

The sensor 17 is for detecting recording sheets,
The actuator 17A is placed near the confluence of the conveyance path formed by the guide 14 and the manual feed conveyance path. Of course, actuator 1
In the arrangement section 7A, guides 14, 15, 16
is cut out.

Roller 18A constituting the registration roller,
Among the rollers 18B, the roller 18A is on the driving side, and the roller 18B is on the driven side. Drive side roller 18
The surface of roller A is made of rubber, and the roller 18B on the driven side is made of stainless steel. The end of the guide 14 on the registration roller side is connected to the rollers 18A, 1.
It is located at a lower position than the contact part of 8B,
The recording paper is not obstructed from entering the contact portion. Further, the guide 14 is connected to the paper feed roller 1.
From the feeding position according to 2, register roller 1
It gradually rises toward 8A and 18B.

The guide 19 includes registration rollers 18A, 18
A conveyance path from B to the platen roller 20 is configured.

The platen roller 20 is a rubber roller and can be driven to rotate intermittently in both forward and reverse directions by a step motor (not shown).

The thermal head 25 has a plate shape elongated in the direction perpendicular to the drawing, and has a large number of minute heating elements arranged in an array in the longitudinal direction of the head, that is, in the direction perpendicular to the drawing. This heating element array arrangement section is hereinafter referred to as a writing section.

The thermal head 25 is held by a bracket 26, and during recording, it is connected to the writing section and the platen roller 20 via an ink sheet IS and a recording paper S.
are in pressure contact with each other along the generatrix of the platen roller 20 in the longitudinal direction. Thermal head 2
5 and the platen roller 20 are hereinafter referred to as a recording section.

The guide 28 is plate-shaped and forms a conveyance path for the recording paper from the recording section to the discharge rollers 30A and 30B. The peeling claw 29 is auxiliary provided to ensure separation of the recording paper S and the ink sheet IS after recording.

Ejection rollers 30A, 30B, 32A, 32B, 3
4A and 34B transfer the recording paper S after recording to the tray 3.
A conveyance path for discharging upward is provided by guides 31A,
31B, 33A, and 33B.

Ejection rollers 30A, 30B, 32A, 32B, 3
4A and 34B both have a plurality of rollers mounted on the shaft in a skewed manner. The discharge rollers 30A, 32A, and 34A are on the driven side and are made of a material that is not easily stained by ink, such as resin or aluminum. The discharge rollers 30B, 32B, and 34B are on the drive side and are made of a material such as rubber that has a sufficient coefficient of friction against the recording paper. Further, these discharge rollers 30A to 34B are all set to the same feeding speed. Moreover, the feeding speed by these discharge rollers is
The feeding speed of the relay roller 27 is set higher than the feed speed of the relay roller 27.

In the end, the recording paper S is transferred from the guide 14 or the manual feeding path to the registration rollers 18A, 18B, .
The guide 19 passes through the platen roller 20 to the recording section, the guide 28, and the discharge rollers 30A, 30.
B, guides 31A, 31B, discharge rollers 32A, 3
2B, guides 33A, 33B, discharge roller 34A,
34B and is discharged onto the tray 3. The recording paper transport path from cassette 4 to tray 3 is
It is shown by a broken line in FIG. Immediately after the discharge rollers 30A and 30B in the recording paper conveyance path, a sensor 38 is installed to detect the recording paper to be discharged after recording.
is provided, and the actuator 38A is inserted into the recording paper conveyance path. Guide 31
A and 31B are plate-shaped, but of course, the portion where the actuator 38A is arranged is cut out.

On the other hand, the ink sheet IS is wound into a roll and set on the upper part of the thermal transfer recording device. For ink sheet IS, first, guide pipe 2
1, and then the guide pipe 23
After wrapping around the upper side, and then wrapping around the lower side of the guide roller 24, it reaches the recording section, passes through the relay roller 27, and then winds up on the take-up spool 3.
9 , and is wound around the take-up spool 39 by rotating the take-up spool 39 counterclockwise by the take-up shaft 40 . Note that the winding shaft 4
0 is provided at the bottom of the device. ink sheet
The transport path of the IS is shown by a chain line in FIG.

Now, the guide pipe 21 is rotatably provided at the top of the device. The buffer guide 22 is a rotatable pipe, and the guide pipes 21 and 23
, and comes into contact with the upper surface of the ink sheet IS, that is, the back surface of the ink sheet IS. Buffer guide 22
A bracket (not shown) that rotatably holds the
Together with the buffer guide 22, it constitutes a buffer guide means. ) is itself swingably held on the rotating shaft of the guide pipe 21, and therefore the buffer guide 22 itself is swingable and can be moved between the position shown by the solid line and the position shown by the broken line. It is now possible to oscillate.

The guide pipe 23 is arranged at the bottom of the device and is rotatable. The guide roller 24 is disposed at the top of the device, is rotatable, is made of foamed rubber, and has a low hardness and a large outer diameter.

The relay roller 27 has a surface formed of rubber or foamed rubber that has sufficient frictional transmission force with respect to the base sheet of the ink sheet IS, and is set at a feeding speed that is 1 to 10% higher than the feeding speed of the platen roller 20. .

The control unit 35 is a circuit system including a CPU, and is mainly composed of a printed circuit board.

The device also has two drive motors (not shown). One of them is the step motor mentioned above, and the others are regular motors for continuous rotation.

Here, if each part is associated with the upper part of the device and the lower part of the device, it will be as follows. As mentioned earlier,
The upper part of the apparatus can be opened and closed with the lid 1 in a hinged manner relative to the lower part of the apparatus.
Guide pipe 21, buffer guide 22, guide roller 24, thermal head 25, relay roller 2
7, discharge rollers 32A, 32B, 34A, 34B,
This is why guides 33A and 33B are provided. Also, as mentioned above, the ink sheet IS is set at the top of the apparatus. The platen roller 20 and others are located at the bottom of the device.

Therefore, as shown in Fig. 3, when the upper part of the apparatus is lifted upward, the upper part of the apparatus opens in a hinged manner with the ink sheet conveyance path (the path indicated by the chain line in Fig. 2) facing the lower part of the apparatus. It turns out.

The cover 37 is swingable around the shaft 37A, and when the upper part of the apparatus is opened, it follows the lid part 1 and rotates to the position shown in FIG. 3.

Note that the swing shaft for opening and closing the upper part of the device is
It is indicated by the symbol X in the figure and FIG.

Next, driving of each part will be explained. As mentioned above, the device has a step motor and a regular motor. These motors are arranged at the bottom of the apparatus, and among these motors, the step motor drives the platen roller 20, the relay roller 27, and the winding shaft 40. Platen roller 2
0 and the relay roller 27 are directly driven by a step motor, but the take-up shaft 40 is driven with constant torque via a friction transmission mechanism.

On the other hand, the normal motor first moves the paper delivery roller 11, the paper feed roller 12, the return roller 13, the drive side roller 18A of the registration roller, and then the side drive side of each ejection roller, that is, the ejection roller. 30
B, 32B, and 34B are driven. Of these,
Return roller 13, discharge roller 30B, 32B, 34B
is driven with constant torque via a friction transmission mechanism.

Each roller is operated according to predetermined timing by an electromagnetic clutch.

Various controls in the recording process are performed by a control unit 35. FIG. 4 shows a flow diagram of this control system.

In the figure, a portion surrounded by a solid line frame indicated by reference numeral 4-1 indicates a thermal transfer recording device. The host system is a system that supplies image signals to the thermal transfer recording device, and is a computer, word processor, communication device, or the like. The host system and thermal transfer recording device are mediated by a video interface. In the figure, the part indicated by the symbol 4-2 surrounded by a broken line is the control unit 3.
It corresponds to 5. This control unit 35 includes a CPU,
It has a video interface, bit unit energy control circuit, RAM, head driver, pulse width determination circuit, AMP, and mechanical driver. The head driver is the thermal head 25 (second
Figure). The mechanical driver is a motor,
Drives clutches, solenoids, etc. The bit unit energy control circuit and pulse width determining circuit will be described later.

The recording process using this thermal transfer recording apparatus will be explained below.

As shown in Figure 3, the upper part of the apparatus is opened in a hinged manner relative to the lower part of the apparatus, and the ink sheet IS wound into a roll is set in a holding mechanism (not shown) at the upper part of the apparatus, and the ink sheet IS attached to the tip of the sheet is taken up. The spool 39 is locked to the take-up shaft 40. After that, if the upper part of the device is closed, the state shown in FIG. 2 will be obtained.

During recording, first, a lifting mechanism (not shown) operates to lift up the leading end of the recording paper S in the cassette 4. As a result, the leading edge of the topmost sheet of recording paper S comes into contact with the paper distribution roller 11.

Subsequently, the paper delivery roller 11, the paper feed roller 12, and the return roller 13 are driven, and each is rotated in the direction of the arrow. Note that since the return roller 13 is driven via a friction transmission mechanism, contact with the paper feed roller 12 causes
A slip occurs in the friction transmission mechanism, and the paper feed roller 12 rotates counterclockwise.

As the sheet distribution roller 11 rotates, the topmost sheet of recording paper S in the cassette 4 is distributed from within the cassette 4. The distributed recording paper S is transferred to the paper feed roller 12.
The paper is conveyed along the guide 14. At this time, the friction transmission mechanism of the paper feed roller 12 is slipping.

Although it is rare, sometimes two or more sheets of recording paper are distributed by the paper distribution roller 11. In such a case, only the topmost sheet is fed toward the registration rollers due to the action of the paper feed rollers 12 and the return rollers 13.

That is, the conveyance force due to friction between the paper feed roller 12 and the recording paper is F _FP , the conveyance force due to friction acting between the recording paper and the recording paper is F _PP , and the return roller 1
Let F _RP be the recording paper return force caused by the friction between 3 and the paper, then these three forces are F _FP > F _PP , F _RP > F _PP ,
It is set so that F _FP > F _RP . In other words, by forming the surfaces of the paper feed roller 12 and return roller 13 with rubber, the relationship F _FP > F _PP and F _RP > F _PP , and the relationship F _FP > F _RP , the return roller This is achieved by setting the maximum transmission torque immediately before slippage occurs in the friction transmission mechanism that transmits rotation to the shaft 13 within a range where this relationship holds true. Because of this force relationship, when two or more sheets of recording paper are delivered and held by the paper feed roller 12 and return roller 13, the return roller 13 rotates clockwise correctly and reaches the maximum position. Except for the top one, pull the other recording papers back to the cassette 4 side. Therefore, even if a plurality of sheets of recording paper are delivered by mistake, only one sheet of recording paper is always sent to the recording section.

In order to realize stable conveyance of the recording paper S, the conveyance speed of the paper feed roller 12 is set higher than that of the paper distribution roller 11, and the reverse direction conveyance speed of the return roller 14 is set higher than that of the paper feed roller 12. It is desirable to make it even larger.

The leading edge of the recording paper S conveyed by the paper feed roller 12 gradually advances upward along the guide 14.
Defeat actuator 17A of sensor 17,
After that, it reaches registration rollers 18A and 18B. As mentioned above, among the registration rollers, the driving side roller 18A has a rubber surface and the driven side roller 18B has a stainless steel roller.
When the registration rollers 18A and 18B enter the contact area between both rollers, the registration rollers 18A and 18B are not yet driven.
Not rotating. The leading edge of the recording paper that is being conveyed is connected to the rollers 18A and 1 by the end of the guide 14.
Since it is located lower than the contact part of 8B, first of all, the stainless steel roller 1 is smooth and slippery.
It hits the circumferential surface of 8A, slides on this circumferential surface, and smoothly reaches the above-mentioned contact portion.

The registration rollers 18A and 18B are rotated after a predetermined period of time after the sensor 17 is turned on, but as described above, when the leading edge of the recording paper enters the registration roller contact area,
It is not driven, but is driven a little later after the above-mentioned entry. During this time, the paper feed roller 12 continues to convey the recording paper S, and therefore, the recording paper S whose leading end is stopped by the contact portion of the registration rollers 18A and 18B is moved between the registration rollers and the paper feed roller. form a slack in between.

Subsequently, the registration rollers 18A and 18B rotate to convey the recording paper S to the recording section.

As described above, since the recording paper S is slackened and then the registration rollers are driven to transport the recording paper, the skew of the recording paper and uneven transport speed that occur between the cassette and the registration rollers are eliminated. It can be corrected and the subsequent transport position of the recording paper can be accurately controlled.

Note that when the registration rollers 18A and 18B rotate, the paper feed rollers 12 and the like are deactivated and follow the movement of the recording paper S by free rotation.

When loading recording paper manually, use guide 1.
The recording paper is fed into the apparatus through the manual feed conveyance path indicated by 5 and 16. The fed recording paper knocks down the actuator 17A with its tip and rushes into the contact portion of the registration rollers 18A and 18B.

The registration rollers 18A and 18B start rotating a predetermined time after the sensor 17 is turned on. If this predetermined time is set to about 0.5 to 1.5 seconds, assuming that the distance from the position where the sensor 17 is turned on to the contact portion of the registration rollers 18A, 18B is 20 mm, a good operational feeling can be obtained.

The time interval from when the sensor 17 turns on to when the registration rollers are driven needs to be different depending on whether the recording paper is fed manually or from a cassette, and these two feeding modes can be distinguished. This is necessary, but this will be discussed later.

Now, when the registration rollers 18A and 18B rotate to send the recording paper to the recording section, the platen roller 20 rotates counterclockwise and grips the leading end of the recording paper S into the recording section. In this way, the recording paper S
is set in the recording section, registration roller 1
8A and 18B are released from driving and left in a freely rotatable state thereafter.

Subsequently, the platen roller 20 is rotated counterclockwise by intermittent driving to cause the recording paper S and the ink sheet S to run toward the thermal head 25.

At the same time, an image signal is applied to the thermal head 25, and writing is performed. In other words, the minute heating element that constitutes the writing section of the thermal head 25 generates heat in response to the image signal, and instantaneously generates heat.
The temperature rises to around 300℃. This heat is transmitted to the ink layer via the base sheet of the ink sheet IS, and the ink in the heated portion is thermally melted and transferred onto the recording paper S.

As mentioned above, this recording device can use recording paper of different sizes, and these
They are transported through the device using a so-called center sorting method. Therefore, if the width of the recording paper used is shorter than the length of the writing section of the thermal head 25, the image signal applied to the thermal head 25 is masked according to the width of the recording paper, and the thermal By timing the latching to the head 25, appropriate image recording is achieved according to the width of the recording paper.

Now, the recording paper S and the ink sheet IS that have passed through the recording section are bonded together due to the adhesive force of the thermally transferred ink.
Although they are stuck together, the two are separated from each other by the relay roller 27. That is,
As mentioned above, the ink sheet IS is extremely thin, so
The so-called stiffness of the ink sheet IS and the recording sheet S are greatly different. Therefore, ink sheet IS
When the conveyance direction of the ink sheet IS is suddenly changed greatly by the relay roller 27, the recording paper S cannot follow the change in the direction of the ink sheet IS due to its elastic force, that is, its stiffness, and the recording paper S automatically changes to the ink sheet IS. Separated and along the guide 28, the discharge rollers 30A, 30
It rushes into the contact area of B. The peeling claw 29 is used when separation of the two sheets fails due to some reason.
This is provided to ensure that the two are separated.

Since the relay roller 27 separates both sheets on its outer periphery, its diameter is preferably made as small as possible. When the diameter of the relay roller 27 becomes smaller, even thinner and weaker paper can be reliably separated, so that a wide variety of paper types can be used as recording paper.

The peeled ink sheet IS is then sequentially wound onto a take-up spool 39.

On the other hand, for recording paper S, discharge rollers 30A, 30
B, guides 31A, 31B, discharge rollers 32A, 3
2B, the guides 33A, 33B, and finally the tray 3 is conveyed by the discharge rollers 34A, 34B.
is discharged upwards. In this way, a desired thermal transfer recorded image is obtained.

The common tangential plane at the contact portion of the discharge rollers 34A, 34B is oriented slightly upward to the right in FIG. Therefore, the recording paper S is discharged slightly upward to the right. In this way, tray 3
Good stock is guaranteed.

Note that the sensor 38 detects the leading edge and trailing edge of the ejected recording paper according to the tilting of the actuator 38A.
By detecting the return and comparing the signal with a theoretical value, not only is it possible to detect a failure in conveyance of the recording paper S, that is, the occurrence of a so-called jam, but also to determine the recording operation completion time.

Also, after finishing writing in the recording section, the ink sheet
The IS is sent to the separation position together with the recording paper S, but if the IS is left as it is and the next recording is performed, the ink sheet portion between the recording section and the separation section will be wasted. Therefore, after separating the recording paper and the ink sheet, the platen roller 20 is reversed, and the part of the ink sheet located at the separating section and the recording section is returned to the recording section. In the case of continuous recording, the paper is pulled back after the last page of recording paper is separated.

This ink sheet pulling back will be described later.

The above is an overview of the recording process in the thermal transfer recording apparatus shown in FIGS. 1 to 4.

Below, some features of the above embodiment will be explained.

The first feature relates to the supply of recording paper S. As described above, in the apparatus of the embodiment, the recording paper S can be supplied using a cassette method or a manual feeding method.

Then, a sensor 17 is arranged near the confluence of the conveyance paths of each supply method, and after this sensor 17 is turned on, rotation of the registration rollers 18A and 18B is started after a certain delay time. ing.

By the way, since the moving speed of the recording paper is generally different depending on whether the recording paper is fed automatically from the cassette or manually, the leading edge of the recording paper is Therefore, the delay time needs to be different depending on whether the supply is from a cassette or manually. Therefore, if the delay time is to be varied depending on the feeding method in this manner, it is necessary to detect the recording paper feeding method and select each delay time. To detect the recording paper supply method,
In this embodiment, the following steps are taken. That is, the presence or absence of the sheet distribution roller 11 being driven is detected, and this result is combined with the detection by the sensor 17 to make a determination. That is, in the case of feeding from a cassette, the paper distribution roller 11 is always driven.
When the paper distribution roller 11 is driven, it is detected that paper is being supplied from the cassette.

On the other hand, when recording paper is fed manually, the paper distribution roller 11 does not operate. Therefore, if the sensor 17 is turned on even though the sheet distributing roller 11 is not driven, it is immediately known that the sheet is being fed manually.

The second feature relates to the relay roller 27. As mentioned above, the relay roller 27 is
The surface is formed of rubber or foamed rubber that has sufficient friction transmission force against the platen roller 20, and is driven by a step motor like the platen roller 20.
The speed of the peripheral surface is set to be 1 to 10% faster, for example, 5% faster than the conveyance speed by the platen roller 20. By configuring the relay roller in this way, the following effects can be obtained.

That is, firstly, the conveying force of the ink sheet IS is improved. As described above, the ink sheet IS and the recording paper S in the recording section are transported by the platen roller 20. That is, the platen roller 20 contacts the back side of the recording paper S, rotates, and conveys the recording paper S. At this time, the ink sheet IS is transported together with the recording paper S by the frictional force exerted by the recording paper S. In this way, the conveyance of the ink sheet IS in the recording section depends on the frictional force between it and the recording paper S, so when the recording paper used has a small coefficient of friction with the ink sheet IS. may cause slippage between the ink sheet and the ink sheet, resulting in failure of ink sheet conveyance. However, since the relay roller 27 has sufficient frictional transmission force to the ink sheet IS, and its circumferential speed is set higher than the conveyance speed by the platen roller 20, the relay roller 27 can
A tensile force is applied that pulls the ink sheet, thereby ensuring reliable transport of the ink sheet IS in the recording section. Since the circumferential speed of the relay roller is higher than the conveyance speed of the ink sheet IS in the recording section, the relay roller 27 applies a tensile force due to friction to the ink sheet IS while moving the ink sheet IS.
We are fighting against IS. Second, due to the above-mentioned tensile force, the ink sheet IS is moved to the relay roller 2.
7 and the recording section, both the recording paper and the recording paper are stretched taut. This allows the ink sheet IS,
It is possible to prevent wrinkles from forming on the recording paper S,
Further, good separation between the two can be achieved.

Third, there is the prevention of uneven feeding of recording paper and ink sheets. In other words, the ink sheet after recording is
The ink is taken up by the take-up spool 39, but as mentioned above, since the take-up spool 39 is driven by a step motor with a constant torque through a friction transmission mechanism, the ink taken up on the take-up spool 39 is taken up by the take-up spool 39. When the diameter of the sheet IS is small, the tensile force of the ink sheet due to winding is large, and as the diameter increases, the tensile force becomes smaller. If the relay roller 27 were not present, this variation in tensile force would be transmitted to the recording section, causing uneven feeding, but because of the presence of the relay roller 27, the above fluctuation would not be transmitted to the recording section.

Note that the relay roller 27 may be rotationally driven via a friction transmission mechanism instead of being directly driven by the step motor.

The third feature relates to the discharge rollers 30A, 30B, etc. As mentioned earlier, the discharge rollers 30A, 30
In B etc., drive side rollers 30B, 32B, 3
4B is the side that contacts the back surface of the recording paper S,
The peripheral surface is formed of a material such as rubber that has a sufficient friction transmission force to the recording paper S, and is driven by a normal motor via a friction transmission mechanism, and the peripheral speed for conveyance is set at the platen roller 20. , is set larger than the circumferential speed of the relay roller 27, and the circumferential speeds of the discharge rollers 30B, 32B, and 34B are equal to each other. In addition, rollers 30A and 32 on the driven side
A and 34A are made of a material that is not stained by ink, such as resin or aluminum.

First, since the circumferential speed of the discharge roller 30B is higher than that of the platen roller 20 and the relay roller 27, the recording paper S is stretched tightly on the guide 28, and wrinkles are prevented from forming in this area. Ru. In addition, the discharge rollers 30A, 32A, 34A are
Since the ink does not stain, the ink on the recording paper adheres to the ejection roller, and then again.
The so-called offset phenomenon, which occurs when images are transferred onto recording paper, can be effectively prevented.

Further, since the conveyance speed of the recording paper S by the discharge rollers 30A to 34A is the same, the recorded image formed on the recording paper S by the transfer ink is transferred to the guide 3.
It will not be rubbed by 1A and 33A.

Generally, when conveying sheet-like materials, it is common sense to set the conveyance speed higher toward the downstream side of the conveyance path to create tension in the conveyed sheet and to stabilize the conveyance. Applying this idea to the ejection path of the paper S, in the case of this device, the ejection path has a large curve, and for example, tension is applied to the recording paper between the ejection rollers 30A, 30B and 32A, 32B. And the recorded image on the recording paper is
It is rubbed by the guide 31A, leaving scratch marks. Therefore, in this device, this problem is solved by making the conveying speed of all discharge rollers equal.

This problem is a common problem when the recording paper ejection path is curved, regardless of whether the upper and lower parts of the device open or close. This method is applicable to general cases where the recording paper ejection path is curved.

The fourth feature relates to the buffer guide 22.

As already mentioned, the buffer guide 22 is pipe-shaped and is rotatably mounted on a bracket (not shown), and the bracket is rotatably held on the rotation shaft of the guide pipe 21.
As shown in FIG. 2, it is possible to swing between the attitude shown by the solid line and the attitude shown by the broken line.

The buffer guide 22 contacts the upper surface of the ink sheet S between the guide pipe 21 and the guide pipe 23 due to its own weight. And the buffer guide 22
is maintained in a suspended state by the tension of the ink sheet between the position shown by the solid line and the position shown by the broken line.

By using such a buffer guide 22, the following effects can be obtained.

That is, the first is a buffering effect when the ink sheet IS is supplied to the recording section. That is, the mass of the ink sheet wound into a roll is prevented from being applied as an inertial load to the feeding force in the recording section.

Second, since the buffer guide always maintains tension on the ink sheet, including when replacing the ink sheet, wrinkles are prevented from forming on the ink sheet.

Third, when the unused portion of the ink sheet IS is pulled back by reversing the platen roller 20 after recording, the amount of the pulled back of the ink sheet is absorbed by the swinging, causing the ink sheet to sag or fold. can be prevented.

This buffer guide can also be applied to general thermal transfer recording devices.

Note that the guide roller 24, which also has a buffering effect, has the effect of making it easier for the recording paper S to enter the recording section.

The fifth feature relates to the attachment of the ink sheet IS (FIG. 2).

As mentioned above, the ink sheet IS is wound into a roll and is removably installed at the top of the device, and supplies the ink sheet to the recording section one after another. sheet
The IS needs to be easy to attach and detach from the device.

In this embodiment, the ink sheet IS is held at the top of the apparatus by a support 401 and a leaf spring 402, as shown in FIG. 5, by holding the spool SP around which it is wound. , equipped on the device.

The spool SP is slightly longer than the width of the ink sheet IS, and slightly protrudes from both ends of the ink sheet wound into a roll, and both ends are held by a holding mechanism as shown in FIG. Therefore, to equip the ink sheet, it is only necessary to push the spool SP into the inside of the support 401 through the opening.
The pushed-in spool SP is stably click-stopped by the spring force of the leaf spring 402 and is set on the top of the device. Also spool SP
To remove the spool from the device, simply
It is only necessary to pull out the SP from the opening under the elastic force of the leaf spring 402.

The spool SP is rotatable relative to the holding mechanism shown in FIG. 5, and rotates counterclockwise as the ink sheet IS is drawn out by the drive of the platen roller 20, thereby delivering the ink sheet.

Now, the support body 401 is provided with a friction member 401A made of cork or the like at a portion that contacts the spool SP. The other parts of the support body 401, the leaf spring 402, and the spool SP are extremely prone to slipping against each other. Therefore, when the spool SP rotates counterclockwise, friction is generated between the spool SP and the friction member 401A.
Since the spool SP acts in the direction of pressing it against the support body 401, the spool SP is held extremely stably at the top of the device during its rotation.

Such a spool holding method can be applied not only to the embodiments but also to a wide range of general recording devices.

A sixth feature relates to the bracket 26 that supports the thermal head 25.

In order to perform correct thermal transfer recording, the accuracy of the relative positional relationship between the platen roller 20 and the thermal head 25 must be maintained. This problem is a so-called alignment problem.

In addition, for proper thermal transfer recording, it is necessary for the thermal head and the platen roller to press each other uniformly in the longitudinal direction, but since the thermal head is in the shape of a long and thin plate as described above, When a pressing force is applied in the thickness direction at both longitudinal ends, deflection inevitably occurs, and the pressing force at the center becomes smaller than at both longitudinal ends, making it impossible to obtain a uniform pressing force over the longitudinal direction. do not have.

Bracket 26 holding thermal head 25
solved the problems of alignment and equalization of pressing force as follows.

FIG. 6 shows the bracket 26 in an explanatory manner.

The bracket 26 has a flat plate portion 261 and a support portion 2.
62, a bent portion 263, and a contact portion 264, and the entire portion is integrally formed.

The thermal head 25 is fixed to the lower surface of the flat plate-like portion 261 of the bracket 26. When fixed to the bracket 26, the longitudinal direction of the thermal head 25 is the Y direction in FIG. 6th
In the figure, the bracket 26 is illustrated in a reduced size in the Y direction, and actually has a length in the Y direction that can hold the thermal head 25 in the longitudinal direction.

The support part 262 has a long hole 2621, and by fitting a pin fixed to an immovable member at the top of the device into the long hole 2621, the bracket 26 can be attached to the top of the device so as to be able to swing freely. be equipped with.

The bent portion 263 has an angle θ with respect to the flat plate portion 261.
It is folded upward to form a shape. Regarding this bent portion 263, the Z direction in FIG. 6 is referred to as the width direction of the bent portion 263.

Note that the angle θ is an acute angle of about 60 degrees to 80 degrees.

A locking piece 2631 for locking a pressing spring is provided at both ends of the bent portion 263 in the Y direction. The contact portions 264 are formed at both ends of the flat plate portion 261 in the Y direction and are bent downward.

Now, referring to FIG. 7, the upper part of the apparatus is closed to the lower part of the apparatus, and the thermal head 25 and the platen roller 20 are in pressure contact with each other. In the figure, reference numeral 265 denotes a pressing spring, which is stretched between the locking piece 2631 at both ends in the Y direction (direction perpendicular to the drawing) and an immovable member on the upper part of the device. It is gender.

On the other hand, a contact member 200 for positioning is attached to the rotation shaft 20A of the platen roller 20.
It is rotatably fitted into A and fixed to an immovable member at the bottom of the device.

Now, when the upper part of the apparatus is opened to the lower part of the apparatus and then gradually closed, the thermal head first touches the platen roller 2 in the middle of the closing operation.
The contact portion 264 of the bracket 26 contacts the contact member 200.

Furthermore, when the upper part of the apparatus is completely closed to the lower part of the apparatus, the thermal head 25 receives an upward pressing force from the platen roller 20, and the bracket 26 rotates clockwise around the pin PN, and the seventh The state shown in the figure is realized. At this time, spring 2
65 is stretched out against its shrinking habit,
The elastic force presses the thermal head 25 against the platen roller 20. of course,
Under normal conditions, at this time, the thermal head 25
An ink sheet is interposed between and the platen roller 20.

The contact portion 264 of the bracket 26 and the contact member 2
00 are brought into close contact with each other at each linear portion, so that the relative positional relationship between the platen roller and the thermal head is accurately aligned.

By the way, the spring 265 is in the Z direction, that is,
The bracket 265 is stretched across the bent portion 263 in the width direction, and the elastic force of the spring 265 acts in the width direction. The bent portion 263 exhibits extremely strong rigidity against bending when a force is applied in the width direction,
Even if force is applied at both ends in the Y direction, the bent portion 263
No bending occurs at all. Therefore, the thermal head 25 can be brought into uniform pressure contact with the platen roller 20 over its longitudinal direction.

Next, as described above, the bent portion 263 is bent at an acute angle with respect to the flat plate portion 261. Therefore, as described above, when the pressing force of the spring 265 acts, this pressing force has a component force in a direction parallel to the flat plate-shaped portion and orthogonal to the Y direction. This component force acts as a force that presses the contact portion 264 of the bracket 26 against the contact member 200 on the platen roller 20 side. This ensures the contact between the contact portion 264 and the contact member 200, and the correct relative positional relationship between the thermal head 25 and the platen roller 20 is always maintained.

The seventh feature relates to the supply of recording paper S to the recording section.

The platen roller 20 is driven intermittently during image recording, but is driven at the maximum speed of the platen roller 20 when feeding the recording paper into the recording section. However, driving the platen roller 20 at the same speed as the registration roller is not a good idea in terms of driving efficiency. Therefore, from this point of view, in this embodiment, the conveyance speed for supplying the recording paper to the recording section is set higher than the conveyance speed by the platen roller 20, so that the first sheet can be recorded quickly. There is. Specifically, registration roller 18
The conveyance speed of the recording paper S by A and 18B is set to about 2.5 times the conveyance speed by the platen roller 20.

As mentioned above, the drive of the registration rollers is released when the leading edge of the recording paper is gripped into the recording section by the platen roller 20, but as described above, the conveyance speed of the registration rollers and the platen roller is high. Therefore, in order to properly perform the above-mentioned bit insertion, it is necessary to devise a method. That is,
For good biting, it is ideal that the conveyance speed by the registration roller and the conveyance speed by the platen roller are equal to each other.

Now, in order to perform the above-mentioned bit insertion well, this device is configured as follows.

That is, referring to FIG. 8, first, the rotation of the platen roller 20 is stopped, and the registration rollers 18A and 18B are rotated by 340 msec. Then, the recording paper moves to the registration roller 18.
A and 18B transport the ink toward the recording section, and its tip end is at the contact area between the platen roller 20 and the thermal head 25 via the ink sheet IS, and is further transported by the registration rollers 18A and 18B.
It is rolled out to form a slight loop.

Subsequently, the rotation of the registration rollers 18A and 18B is stopped, and at the same time, the platen roller 20
is driven and rotates counterclockwise for 180msec. During the first 90 msec of this 180 msec, the platen roller 20 absorbs most of the loop of the recording paper while biting the leading edge of the recording paper into the recording section. Subsequently, after the above 90 msec has elapsed, the registration roller is rotated again by 90 msec. During this time, the platen roller also rotates, and the recording paper is completely gripped into the recording section.

The 90 msec period between when the rotation of the registration roller is stopped and then rotated again is a period to absorb the difference in conveyance speed between the platen roller and the registration roller.If this stop period is not provided, the recording paper The loop formed by the blade becomes too large, making it impossible to insert it into the mouth smoothly.

The mechanism of the above-mentioned biting can also be seen as follows.

That is, as described above, if the conveying speed by the platen roller is V, then that by the registration roller is 2.5V. Therefore, in Figure 8, if we focus on the 180 msec during which the platen roller rotates, at this time, the registration roller is
Stops rotating for 90msec, then rotates for 90msec.
Therefore, the average conveyance speed by the registration roller during this 180msec is (90msec x
2.5V)/180msec=1.25V, and the difference between this average conveyance speed and the conveyance speed V of the platen roller is 0.25V.

In other words, the above-mentioned method of inserting the grip is that, by intermittent driving of the registration roller, the average conveying speed of the recording paper approaches the conveying speed of the platen roller, thereby perfecting the grip. There is.

Therefore, if possible, more ideal gripping may be achieved by controlling the intermittent drive of the registration rollers to make the average conveyance speed even closer to the conveyance speed of the platen rollers. . However, from a practical point of view,
Control as shown in FIG. 8 above is sufficient.

The eighth feature relates to the timing of recording paper distribution during continuous recording. That is, in this thermal transfer recording apparatus, recording is started by a print command from the host system (FIG. 4).
This print signal, if only one page is recorded,
It turns off after receiving the "printing" signal from the recording device. However, in the case of continuous recording, it is turned on. In the case of continuous recording, if the print signal is on at the stage when the trailing edge of the previous recording paper is detected by the sensor 17, the next recording paper is dispensed. This recording paper has registration rollers 18A, 1
8B waits until the leading edge is bitten, and is fed into the recording section at a timing such that the leading edge does not overlap the trailing edge of the previous recording paper. These operations are controlled by the control unit's CPU.

The ninth feature relates to the timing of pulling back the ink sheet.

As mentioned above, in this embodiment, the ink sheet IS is pulled back in order to use the ink sheet IS as efficiently as possible. That is, after the recording of the last page is completed, the recording paper and the ink sheet are further conveyed, and both are transferred to the relay roller 2.
After complete separation in step 7, the unused portion of the ink sheet between the separation point and the recording section is pulled back to the recording section.

To do this, it is necessary to detect when the trailing edge of the recording paper reaches the separation point. A possible method for performing this detection is to detect the length of time, for example, from when the sensor 17 detects the trailing edge of the recording paper until the trailing edge reaches the separation point.

However, in the device of this embodiment,
In order to improve the recording speed, a method is used in which lines with "all white" image information are skipped. The presence or absence of skips varies depending on the image information, and depending on the number of skips, the time from when the trailing edge of the recording paper is detected by the sensor 17 until the trailing edge reaches the separation point is longer or shorter. Therefore, detection based on time as described above is impossible.

Therefore, in this embodiment, the sensor 17
The above-mentioned detection is performed by counting the number of drive lines of the platen roller 20 from when the trailing edge of the recording paper is detected until the trailing edge reaches the separation point. This is also controlled by the CPU of the control unit 35.

The tenth feature relates to temperature monitoring.

In this embodiment, the parts that generate a large amount of heat are the thermal head 25 and the power supply.

The amount of heat generated changes depending on the image information, that is, whether there is a lot of white information or a lot of black information, so the instantaneous power supply capacity has a maximum value (when one line is completely black). Although this is necessary, thermal design based on this maximum value would increase the size of the device, which is not a good idea.

Therefore, in this example, the thermal design of the power supply is performed at 120W for the maximum power consumption of 300W.
The thermal head 25 is not particularly provided with a heat sink or the like.

However, a thermistor is attached as a heat detection element to the thermal head 25 and the power transistor of the power supply, and the CPU of the control unit 35 monitors it. This thermistor is commonly used for determining the pulse width of an image signal, which will be described later.

During recording, the temperature of either the thermal head 25 or the power transistor (not shown) reaches a preset limit temperature, that is,
When the temperature exceeds 60°C for the thermal head 25 and 110°C for the power transistor, only the thermal transfer recording on the recording paper that is currently being recorded continues and ends, and then the thermal transfer recording device is placed in a "waiting" state for a certain period of time. During this time, the device can be cooled without recording.

In experiments, when recording ordinary character images, the system did not enter a "waiting" state even after two hours of continuous recording. Therefore, under normal recording conditions, it is considered that there is almost no waiting state.

The eleventh feature relates to control of the energy applied to the thermal head 25.

When a pulse current is passed through the individual tiny heating elements that make up the writing section of the thermal head 25 as an image signal, the temperature of the heating elements instantly and rapidly increases to 300°C.
It rises to the front and back, and then falls somewhat gradually due to heat radiation. The characteristics of this rise and fall are
It changes depending on the substrate temperature of the thermal head 25 and the pulse width of the pulse current.

As described above, when a pulse current is passed through the heating element, the temperature of the heating element falls less sharply after the peak than the rise. Therefore, if the same heating element is driven continuously, the next generation of heat will overlap before the temperature has sufficiently decreased, and the temperature of the heating element will increase cumulatively, causing damage to the ink sheet IS and damage to the ink. This causes problems such as a decrease in image resolution due to excessive transfer.

In this embodiment, this problem is solved by controlling the energy applied to the thermal head 25.

That is, in this embodiment, the writing section of the thermal head 25 is divided into four blocks in the longitudinal direction, and writing is performed twice for each line. Furthermore, each time it is written, it is compared with the information on the immediately previous line, and only the bits for which the image information was white in the immediately preceding line are written twice, and the number of bits for which the image information was black in the immediately preceding line is not written. Do it only once.

This control is performed by the bit unit energy control circuit shown in FIG.

In other words, the bit unit energy control circuit is
When an image signal for one line is received from the video interface, the head driver is driven by this image signal to perform writing, and the image signal is stored in the RAM. Continuing on, the next one
When it receives an image signal for a line, it reads the image signal of the immediately previous line from the RAM, compares the signals, and writes only the bits that were white in the immediately previous line.

By the way, as mentioned above, the rise and fall characteristics of the heating element also depend on the substrate temperature of the thermal head 25, so when the substrate temperature itself becomes high, it becomes difficult to control the applied energy in bit units as described above. Even if this is done, the temperature of the heating element will increase cumulatively, which may cause problems such as damage to the ink sheet.

Therefore, in this embodiment, this problem is solved by using a pulse width determining circuit (Fig. 4) to control the pulse width itself of the pulse current applied to the heating element according to the substrate temperature. . That is, as the substrate temperature rises, the pulse width becomes smaller. This control, of course,
This is performed by the CPU of the control unit 35.

Note that the substrate temperature is detected by the thermistor mentioned in the explanation of the tenth feature.

The twelfth feature relates to shifting the application of image signals for each recording paper in the writing section when images of the same format are continuously recorded.

Some images that are thermally transferred and recorded have ruled lines, such as traditional symbols. When images of the same format having such ruled lines are continuously recorded, a specific heating element in the thermal head 25 is continuously used to record the ruled lines, and the frequency of use of the same heating element is concentrated. This will adversely affect the lifespan of the thermal head.

Therefore, in this embodiment, in such a case, the above problem is solved by shifting the application of the image signal by 1 bit in the writing section within a range of 8 bits for each recording paper. .

As a result, the device for recording images on recording paper is
Although there is a deviation depending on the recording paper, the amount of deviation is
Since it is only 8 bits at most, or 1 mm, it is not a problem.

(Effects) As described above, according to the present invention, a novel thermal transfer recording device can be provided.

In this thermal transfer recording device, the upper part of the device is
Since the ink sheet conveyance path is opened and closed in a hinge-like manner with respect to the lower part of the apparatus, it is extremely easy to install and replace ink sheets in the apparatus, and to deal with jams in recording sheets.

In addition, in the recording section, the platen that transports the ink sheets and recording sheets is provided at the bottom of the device, and the step motor that directly drives the platen is also placed at the bottom of the device, so the top of the device is free of heavy objects such as motors. Since it is not mounted, the top of the device can be easily opened and closed.

In the embodiment, the ink sheet wound into a roll was set at the top of the device, but it may also be set at the bottom of the device. By doing so, the opening/closing operation of the upper part of the device can be made easier.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the external appearance of one embodiment of the present invention, FIG. 2 is an explanatory front view showing only the main parts of the inside of the above embodiment, and FIG. FIG. 4 is a flowchart showing the control system in the above embodiment; FIG. 5 is a diagram illustrating the holding of the take-up spool in the above embodiment. , FIG. 6 is an explanatory perspective view showing the bracket for holding the thermal head in the above embodiment, FIG. 7 is a diagram for explaining the function of the bracket in the above embodiment, and FIG. 8 is a recording FIG. 6 is a diagram illustrating rotational driving of a platen roller and a registration roller to feed a sheet into a recording unit. 1... Lid (the upper part of the device opens and closes together with this lid), 2... Main body (the lower part of the device is fixed to the main body), 3... Tray, 4... Cassette,
18A, 18B... Registration roller, IS... Ink sheet, S... Recording paper as a recording sheet,
20... platen roller, 25... thermal head, 27... relay roller, 30A, 30B,
32A, 32B, 34A, 34B...discharge roller,
31A, 31B, 33A, 33B... Guide.

Claims (1)

[Scope of Claims] 1. A recording sheet is superimposed on the ink layer of the ink sheet, both sheets are run against a thermal head, and ink is applied from the back side of the ink sheet by the thermal head in accordance with an image signal. A thermal transfer recording device that heats and melts ink in a layer selectively and transfers the melted ink onto a recording sheet to obtain a recorded image on the recording sheet, and holds the ink sheet in a movable manner. The upper part of the device can be opened and closed in a hinge-like manner with respect to the lower part of the device, with the ink sheet conveyance path in front of it, and the upper part of the device can be opened and closed in a hinged manner with respect to the lower part of the device. A buffer guide means for applying buffering tension to the ink sheet and a thermal head are provided in the upper part of the apparatus, and together with the thermal head, the ink sheet and the recording sheet are clamped and pressed in the recording section, and are driven to rotate intermittently. A thermal transfer recording device, characterized in that a platen roller for running both sheets relative to a thermal head is provided at a fixed position at the bottom of the device.