JPS6367165A - Serial color thermal printer - Google Patents

Abstract

PURPOSE:To reduce the number of transmission signals and to enhance reliability by reducing erroneous operation due to the contact inferiority of a connector part, by providing a control circuit board controlling operation wherein a thermal head is contacted with recording paper under pressure on the basis of a memory signal, or the pressure contact of said thermal head with the recording paper is released, to a reciprocally movable carriage part loaded with a plurality of thermal head units and the drive mechanisms at every head units. CONSTITUTION:A carriage part reciprocally moves through the slide bearing provided to a housing 21. A head pressure contact and release mechanism for contacting four head units 22, 23, 24, 25 with a flat platen under pressure or releasing said head units from the platen and an ink ribbon take-up mechanism are provided to the carriage part, and a sub-control circuit board 60 having a control circuit for driving the head units is provided thereon. A wire for transmitting a control signal to a solenoid, the wire of a sensor detecting the presence of an ink ribbon and the wire of a microswitch detecting the presence of an ink ribbon cassette are connected to the sub-control circuit board 60.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a thermal transfer type serial color thermal printer.

(Prior Art) Printers are widely used as output devices for information equipment, and as CRT displays become more color-oriented, the need for color printers has increased, and various color printers have come on the market.

Conventional color printers include relatively low-cost printers that display color in several colors with no gradations, and high-priced printers that display full color with 16 to 64 gradations. In addition, recording methods include thermal transfer method, inkjet method, and dot impact method.
(Yellow), M (Magenta), and C (Cyan) are mixed to print seven colors, but the black obtained by mixing the three colors Y, M, and C is pure. Since it is not a black color, only black is prepared separately.
Four colors are used: Y, M, C and B (black).

By the way, there are serial printers that record one line sequentially in the line direction on recording paper, and line printers that record one line at the same time.Now, let's think about conventional thermal transfer serial color printers. As you can see, an ink ribbon with hot-melt inks of Y, M, and C applied sequentially on a transparent resin base is stored in a cassette and used, and unnecessary colored parts of this ink ribbon are removed according to the color to be recorded. The necessary colored portions are overlaid and melted by the head's heat generated by the recording signal, and the color is transferred onto the recording paper. However, with this type of recording method using an ink ribbon, the part of the ink ribbon that is not fed is wasted, and if you try to record colors other than Y, M, and C, you need to go back and forth three times. There is a problem in that the recording speed is restricted and it is not suitable for high-speed recording.

The same problem occurs when monochrome recording is performed using this serial color printer.

Therefore, the present invention is based on a patent application filed on August 28, 1986, titled ``In serial color thermal printer J, with the purpose of eliminating wasted ink ribbons and increasing recording speed.''
A plurality of ink ribbon cassettes of different colors are arranged in a predetermined order in a carriage, and each ink ribbon cassette is provided with a thermal head that heat-fuses the ink ribbon of each ink ribbon cassette, and the thermal head is attached to the recording paper based on a recording signal. We have proposed a serial color thermal printer configured to wind up an ink ribbon in synchronization with the crimping operation when crimping or releasing the crimping.

By the way, in this newly proposed printer, a plurality of ink ribbon cassettes, a plurality of thermal head units for melting the ink ribbon for each ink ribbon cassette, and a device for releasing pressure on these head units are provided in the carriage section. Since the number of driving solenoids equivalent to the number of heads and the number of ribbon sensors equivalent to the number of cassettes for detecting the presence or absence of ink ribbons are installed, the number of signals sent and received becomes extremely large. Furthermore, if drive voltage is applied to multiple (for example, four) head units at the same time, the drive current becomes extremely large, causing the effect of voltage drop, which requires increasing the cable pattern width and reducing the number of transmitted signals. Either the number of cables and the width of the cables need to be increased further due to the increase in the number of cables, or on the other hand, there is a demand for miniaturization of printers, which is difficult in terms of space and may cause malfunctions.

(Object and Structure of the Invention) The present invention has been made in view of the above points, and an object of the present invention is to transmit a large number of signals without significantly increasing the number or width of cables in a color thermal printer. In order to achieve this, a circuit board for head drive control is mounted on a reciprocating carriage portion on which at least a plurality of thermal head units and a drive mechanism for each head unit are mounted.

(Example) The present invention will be explained below based on the drawings.

FIG. 1 is a perspective view of the external appearance of a serial color thermal printer according to the present invention. An operation section 4 is provided on the right side of the -1- plane. By opening the opening/closing lid 3 to one side, color ink ribbon cassettes 5, 6, 7, and 8 can be replaced. The operation unit 4 includes an online switch for connecting the printer to an external device (such as a computer), a density adjustment button, a vapor foot button for feeding recording paper, as well as an alarm for recording paper out, an ink ribbon out warning, and a cassette. There is also a display section that displays a warning that the device is not loaded.

FIG. 2 shows the serial color thermal printer according to the present invention with the cover removed, and P is recording paper.

A main control circuit board 10, a carriage section 20, a paper feed section 30, and a power supply section (not shown) are arranged on the main body base l.

The main control circuit board IO receives recording signals supplied from the outside and signals from various sensors and switches provided in the printer, and controls the paper feed motor of the paper feed unit 30 and the carriage unit 20.
This is a circuit board that outputs control signals to the carriage motor and a sub-control circuit board attached to the carriage section 20, which will be described later.

The carriage part 20 has a housing sink 21 (FIGS. 3 and 7).
4 head units 22, 23, 2 on the top (see figure)
4.25, a head pressure release mechanism for pressing and releasing the head units 22 to 25 from the flat platen 92, and an ink ribbon winding mechanism, and a mechanism for driving the head units. A sub-control circuit board 60 (see FIG. 7) having a control circuit is disposed, the whole is covered with a carriage cover 26, and four ink ribbon cassettes 5.6, 7.8 are loaded onto this carriage cover 26. The carriage part 20 as a whole engages with two wooden guide shafts 27 and 28 via a sliding bearing (not shown) provided in the housing 21, and reciprocates by a mechanism described later. It is configured as follows.

As shown in FIG. 4(a), each of the head units 22 to 25 includes a heating element 22a formed of a resistive heating element and a heat sink plate 22b made of metal such as aluminum that functions as a heat sink.
This heat dissipation plate 22b has a bearing part 22d on the lower side.
, 22e are fixed to the head holder 22c with screws.

A hanging piece 2 is attached to one bearing portion 22e of the head holder 22c.
2f is formed, and one end of a tension spring 42, which constitutes a part of a head pressure release mechanism to be described later, is hooked to this hanging piece 22f.

34 is a flat cable that supplies electricity to the heating element 22a, one end of which is connected to the sub-control circuit board via a connector.

As can be seen from FIG. 3, the head units 22 to 25 having such a configuration have their bearing parts (22d and 22e) successively and loosely inserted into the holder shaft 31 fixed at a position close to the recording part side of the housing 21J. A collar 32 of a predetermined length is interposed between each head unit, and the head units 22 to 25 and the collar 32 are urged in the axial direction by a compression spring 33 from one side of the head unit 25 (on the right side in the figure). This is how it is installed. compression spring 3
By appropriately selecting the spring constant 3, each head unit can rotate independently around the Holt shaft 31, and there is no play between the head units, making it possible to always hold the head in an accurate position. .

Next, the head pressure releasing mechanism will be explained. As can be clearly seen from FIG.
On the top, there is a solenoid 40 corresponding to each head unit,
A lever 41 is provided that is rotatable around a lever shaft 41a that is integrally fixed to a mounting plate that holds the solenoid 40, and the other end of the tension spring 42 mentioned above with respect to the head unit is attached to one end of the lever 41. hung, lever 4
One end of an auxiliary spring 43 is hooked to the other end of 1.

The other end of the auxiliary spring 43 is hooked onto a pin 44 installed on the housing 21, and a plunger 40a of a solenoid 40 is loosely connected to the lever 41 near the other end. Further, a protrusion 41b is formed in the center of the lever 41, and a protrusion 45 for controlling winding of the ink ribbon, which will be described later, is provided at the tip of the protrusion 41b. The solenoid 40 used here has a built-in permanent magnet, and if it is momentarily energized only when energized, the plunger 40a is held in the attracting position or the withdrawn position by the permanent magnet even if the energization is cut off thereafter. It is something.

When the solenoid 40 is energized and the plunger 40a is attracted (solid line position in FIG. 3), the tension spring 42 is pulled due to clockwise rotation of the lever 41, and the head unit (for example, 22) or the holder shaft is pulled. 31 to press the heating element 22a against the flat platen 92 (see FIG. 1) with a predetermined pressure. When a reverse voltage is applied to the solenoid 40 to energize it, the plunger 40a is pulled out (as shown by the chain line in FIG. 3), and in conjunction with the action of the auxiliary spring 43, the lever 4
1 or counterclockwise, and as a result, the head unit rotates on the holder shaft 31, and the heat generating element 22a is placed on the flat platen 9.
Stay away from 2. The operation of each head unit is exactly the same.

Next, the ink ribbon winding mechanism will be explained.

As shown in FIG. 5, the ink ribbon winding mechanism includes a drive gear 51 integrally formed with a gear 51a in two parts and a timing pulley 51b in the lower part, and can swing coaxially with this drive gear 51. lever 52 and gear 5 of drive gear 51
An idler gear 53 that constantly meshes with the idler gear 1a, and a winding gear 54 that meshes with and disengages from the idler gear 53.
It is composed of. As shown in FIG. 6, the rotation shaft 52a of the lever 52 and the shaft 51c of the drive gear 51 are inserted into the boss 55 formed on the housing 21 of the carriage section 20, and one arm of the lever 52 is inserted into the boss 55 formed on the housing 21 of the carriage section 20. 52
A shaft 53a of an idler gear 53 is inserted through a protrusion hole 52c formed in b. Further, a winding member 56 having a felt 56a stretched on its upper surface is provided coaxially with the winding gear 54 in close contact with the lower surface of the gear 54, and the winding member 56 extends above the winding gear 54. A spring 56c is provided around the shaft 56b of the take-up member 56, and a winding top 57 is provided at the tip of the shaft 56b.
is installed.

The lever 52 is provided with another arm 52d, and as will be described later, the tip of this arm 52d works together with the protrusion 45 of the protrusion 41b of the lever 41 of the head pressure release mechanism to wind up the ink ribbon. Control behavior.

A timing belt 59 stretched between two side plates 57 and 58 attached to the main body base plays a major role in transmitting power to the ink ribbon winding mechanism. On one side of the timing belt 59, uneven portions are formed at regular intervals, and the driving gear 51 is connected to the timing belt 59 through the uneven portions.
The timing pulley 51b is engaged with the timing pulley 51b.

FIG. 7 shows the arrangement of the sub-control circuit board 60.

The sub-control circuit board 60 is disposed at one side of the center of the housing 21 shown in FIG. A control circuit for controlling the crimping release mechanism 25 and the ink ribbon winding mechanism is provided, as well as a connector 61 of the flat cable 34 and the main control circuit board 10 for transmitting recording signals to the head units 22 to 25.
An l connector 62 of the flat cable 200 for transmitting signals between the two terminals and the like is provided. Although not shown, the sub-control circuit board 60 also includes the housing 2.
A wire that transmits a control signal, a wire that connects to a sensor that detects the presence or absence of an ink ribbon, or a wire that connects to a microswitch that detects the presence or absence of an ink ribbon cassette is connected to the solenoid 4° installed in 1 and 2. There is.

If the sub-control circuit board 60 is mounted on the carriage section 20 separately from the main control circuit board lO in this way, even if the number of heads is plural, the number of flexible full flat cables can be reduced. The cable can be held in the same manner as in the conventional case of one head, and the cable resistance can be reduced to reduce the voltage drop caused by the head drive current.

In addition to the above components, the carriage section 20 is provided with an ink ribbon sensor 64 on a sub-control circuit board at a position corresponding to each ink ribbon cassette (see FIG. 2). The ink ribbon sensor 64 is a light transmission type sensor, and the ink ribbon runs between a light emitting part and a light receiving part, and detects the presence or absence of the ink ribbon and the end thereof. Of the four types of ink ribbons used, Y (yellow), 9M (magenta), and C (cyan) ink ribbons are transparent, so an aluminum vapor-deposited piece is attached to the end of the ribbon, and B (black) is used. By making the ends of the ink ribbons transparent, it is possible to detect the ends of all four types of ink ribbons using the same type of sensor.

On the other hand, a microswitch (not shown) for detecting the presence or absence of a cassette is provided in the housing sink 21 of the carriage portion 20. This is because the ink ribbon during color transfer is transparent, so the presence of the ink ribbon is detected even if the ink ribbon cassette is not loaded, and when color-forming recording paper is used instead of an ink ribbon. This is because an ink ribbon cassette is not required when recording in the thermal recording mode, so it is necessary to detect the presence or absence of a cassette. The carriage cover 26 is provided with an actuator that prevents removal, and when a cassette is loaded, a microswitch for detecting the presence or absence of a cassette is actuated via this actuator, thereby detecting the presence or absence of a cassette.

The carriage cover 26 has a notch 26 for avoiding the head units 22 to 25 and the ink ribbon sensor 64.
a and an escape hole 26b for projecting the ink ribbon winding top 57 upward, and two dowels are provided for each cassette on the second side for positioning when loading the cassette. It is being

Next, the ink ribbon cassette will be explained.

The ink ribbon cassettes 5 to B loaded on the carriage cover 26 have the same structure for all four colors of Y, M, C, and B as shown in FIG. B, Y, M, and C are arranged in this order. The ink ribbon cassettes are arranged in a straight line connecting the supply reel and take-up reel or perpendicular to the longitudinal direction of the flat platen 92 (that is, the moving direction of the carriage section 20), so that the width of one cassette is narrow, and four cassettes are arranged. The width of the carriage section 20 is made as short as possible even when the carriage section 20 is loaded
The length of the reciprocating path is shortened, and the amount of ink ribbon stored in the cassette is increased.

The ink ribbon cassette 5 is formed into a thin box shape with a main body 5a and a cover 5b, and has a rotatable supply cassette 5c on which ink ribbons R of each color are wound inside, and a winding cassette 5d rotated by a winding top 57. is provided. At the front of the cassette, a part of the head unit 22 (
a recess 5e into which the ink ribbon sensor 64 (not shown in chain lines) can be inserted;
f is formed so that the ink ribbon R contacts the head unit 22, and the ink ribbon sensor 64
In order to cross the line, an entrance/exit is provided, and three guide rollers 5g are provided along the running path from the supply reel to the head section. These guide rollers 5g are rotatable around fixed shafts, and are provided with flanges on the top and bottom to prevent the ribbon from shifting in the vertical direction when the ink ribbon runs. Two fixed guides 5h are provided along the travel path from the head section to the winding hub 5d. Although not shown, a hole is formed in the bottom surface of the cassette body 4a to engage with a tab provided on the top surface of the carriage cover for positioning when loading the cassette. In addition, a compression spring (not shown) is installed between the cassette cover 5b and the supply reel, or this compression spring applies a frictional load to the supply reel to prevent walnuts generated in the ribbon traveling path during ribbon winding. It has the effect of preventing

Next, the drive mechanism of the carriage section 20 will be explained.

As can be seen from FIG. 2, a carriage motor (Stella Pink Motor) 100 is fixed to a stand 71 on the main body base 1.
A timing pulley (not shown) fixed to the shaft of the carriage motor 100 is integrated with a shaft attached to one corner of the stand 71, or is engaged with a timing pulley 72, 74.

A timing belt 73 is stretched between the timing pulley fixed to the shaft of the motor 100 and the timing pulley 72, and an uneven belt is provided on one side between the pulley 74 and the timing pulley 75, which is also mounted on the main body base l. A timing belt 76, which is formed in a circular shape, is stretched in a loop shape, and a portion of the timing belt 76 is fixed to the housing 21 of the carriage part 20 by an appropriate method.

When the carriage motor 100 rotates forward or reverse, the timing belt 76 reciprocates in the direction of the arrow, and the housing 21 and therefore the carriage portion 20 reciprocate accordingly.

Next, the paper feed section 30 will be explained. The paper feed section 30 consists of a mechanism that feeds the recording paper P line by line during recording, and includes a paper feed motor 80 and a gear train 81a, 81b that transmits the rotation of the paper feed motor 80.

81c, 81d, and a pair of paper feed rollers 82a and 82b rotated via the gear trains 81a to 81d,
These paper feed rollers 82a.

The gear trains 81a to 81d and the paper feed rollers 82a and 82b are connected to the side plate 8 fixed to the main body base IJ2.
It is supported by 4.85.

A paper feed roller 82a is provided on the outside of the side plate 84.

A paper feed knob 87 is fixed to the mounting shaft 86 of 82b, and by turning this paper feed knob 87 by hand, the paper feed rollers 82a, 82b can be rotated, thereby pressing the paper feed rollers 82a, 82b. Rollers 83a, 83b
You can manually feed the recording paper held between the

On the other hand, the pressure roller shaft 88 to which the pressure rollers 83a and 83b are fixed is urged in the direction of the shaft 86 by the compressive force of the spring 89.
2b and a pressure roller 83a.

83b, the cam plate 90, which is rotatably fixed to the side plate 84 with a spring bias in one direction about a shaft 89, is moved in a direction opposite to the spring bias. By manually rotating the pressure roller shaft 88 to the shaft 8
6 against the compressive force of the spring 89, thereby releasing the clamping force between the paper feed rollers 82a, 82b and the pressing rollers 83a, 83b, and allowing the recording paper to be freely taken out.

On the other hand, a flat platen 92 is provided near the paper feed section 30. As shown in FIG. 9(A), the platen 92 is a U-shaped metal frame 92 stretched between the side plates 84 and 85.
A long flat rubber plate 92b is held in the frame 92a, and semicircular protrusions 92c are formed at both ends of the frame 92a, and these portions are connected to the side plate 8 as shown in FIG.
It is engaged through a platen holter 93 having a hole 84a attached to a 4°85 (only the side plate 84 is shown) and can be rotated slightly around a protrusion 92c.

Next, the recording operation by the serial thermal printer according to the present invention having the configuration described in "2" will be explained.

When the printer is turned on, the carriage section 20 once moves to the left end, then moves to the right (in the recording direction) and stops at approximately the center.

Before starting recording, open the open/close M3 and load the ink ribbon cassettes 5, 6, 7.8 from the right onto the carriage cover 26 in the order of black, yellow, magenta, and cyan, and operate the roller release lever (not shown). By moving the cam plate, the pressure contact between the paper feed rollers 82a, 82b and the pressing rollers 83a, 83b is released, and the recording paper P is loaded as shown in FIG. After loading, return the roller release lever to its original position and release the paper feed rollers 82a, 82b.
By bringing the pressure rollers 83a and 83b into pressure contact again and manually turning the paper feed knob 87, the recording paper is advanced to a position suitable for recording.

At this time, the main control circuit of the main control circuit board 10 uses a microswitch (not shown) to detect the presence or absence of an ink ribbon cassette, and an ink ribbon sensor 64 to detect the presence or absence of an ink ribbon. Display.

Now, when the online switch of the operation section 4 is turned on with the ink ribbon cassettes 5, 6, 7, and 8 loaded and the ink ribbons stored in each cassette, a recording signal from an external recording information output device (for example, a personal computer) is output. is input to the printer and the recording operation starts.

Once the carriage unit 20 reaches the left end home position, it begins to move in the recording direction (rightward).

When the carriage motor 100 rotates in one direction, the carriage part 20 transmits the rotation to the pulley 72 via the belt 73, and as a result, when the timing pulley 74 is rotated integrally, the rotation is transmitted to the housing 21 or the right side via the timing belt 76. move in the direction.

For example, if you try to print in orange, the orange color is created by mixing Y (yellow) and M (magenta), and first, the ink ribbon cassette 7 of Y, which reaches the printing area first as seen in the recording direction, cooperates with the ink ribbon cassette 7 of Y. A voltage is applied to the heating element 24a of the head unit 24 via the flat cable 34 (see FIG. 4), and a printing signal is applied when the heating element 24a reaches the printing area.

On the other hand, since the head unit 24 needs to be in pressure contact with the recording paper via the ink ribbon (Y) slightly before reaching the printing area, the solenoid 40 is energized. When the solenoid 40 is energized, the plunger 40a is attracted and assumes the position shown in the solid line in FIG. The heating element 24a is brought into pressure contact with the recording paper. At this time, the flat platen 92 can swing around circular protrusions 92c provided at both ends via platen holders 93 attached to the side plates 84 and 85, so that it is in close contact with the heating element surface of the head unit 24. Become.

On the other hand, as the carriage section 20 moves to the right, the drive gear 51 is rotated in the direction indicated by the arrow in FIG. The idler gear 53 is also rotated in the direction of the arrow.

When the head unit 24 approaches the print area, the solenoid 40 is energized and the plunger 40a is sucked, causing the plunger 40a provided at the tip of the protrusion 41b of the lever 41 that was in contact with the tip of the arm 52d of the lever 52 to Since the protrusion 45 is removed from the arm 52d, the lever 52 is connected to the drive gear 51.
As a result of the counterclockwise rotation of , it is driven counterclockwise, and as a result, the idler gear 53 meshes with the winding gear 54 and rotates. The rotation of the winding gear 54 is caused by the winding member 5
shaft 56b via felt 56a and spring 56c of 6.
, and further transmitted to the winding top 57. Since the winding top 57 is engaged with the winding hole of the ink ribbon cassette (Y) 7, the ink ribbon (Y) is wound up.

When the head unit 24 reaches the printing area, the heating element 2
4a is heated according to the print signal, and the heat causes the ink ribbon (Y
) is melted and attached to the recording paper. Thereafter, the ink ribbon cassette (M) 6 cooperates with the adjacent ink ribbon cassette (M) 6 after a predetermined time delay. The head unit 23 is pressed against the recording paper, and then a print signal is applied to heat the heating element 23a, and the head unit 23 is pressed against the recording paper.
M (magenta) color is printed on the Y (yellow) color printed by the print unit 24. In this way, orange, which is a mixed color of Y and M, is printed on the recording paper.

When printing for 1 line is finished, first the solenoid 40 of the head unit 24 for Y is deenergized, and as a result, the plunger 40a is pulled out (as shown by the chain line in FIG. 3), and the compressive force of the spring 42 causes the plunger 40a to be pulled out. The head unit 24 is separated from the recording paper. After the specified time, the ink ribbon (
The head unit 23 for M) is similarly separated from the recording paper.

”Printing signals to the two consecutive head units 24 and 23 and timing R of energizing and deenergizing the solenoid 40
These are H, which is the head spacing, and L, which is the moving distance of the carriage section 20 per l pulse applied to the carriage motor 100.
When the applied pulse frequency is f, it is determined as H/fLsec.

The printing characters are formed in the following manner.

Characters are formed, for example, in a 9×8 dot matrix, and the heating elements 24a of the head unit 24 are provided vertically on nine sides at regular intervals, and a voltage is selectively applied depending on the characters to be printed. . Further, the pitch in the lateral direction can be obtained by applying a voltage in synchronization with a pulse signal level having a constant period depending on the moving speed of the carriage. The pulse frequency applied to the heating element is limited by the thermal responsiveness and durability of the heating element. - For example, the pulse frequency applied to the heating element is kept constant, and the printing pitch is obtained by selecting the moving speed of the carriage.

(2) When printing for a line is completed and all the head units used in connection with the printing are separated from the recording paper, the carriage motor 100 is reversed and the carriage section 20 returns to the home position. After that, the paper feed motor 80 is driven, and the gear trains 81a to 81d and the set of paper feed rollers 82a, 82
The recording paper is fed by one line via b.

Printing is performed by repeating the above operations.

In the above embodiment, an example was explained in which orange color printing is performed using two colors, Y and M, but in addition, it is also possible to print in green, which is a mixture of Y and C, and purple, which is a mixture of M and C. Yes, each ink ribbon cassette can also record in a single color.

Further, in the above embodiment, since the ink ribbon is wound up when the head unit is crimped, the ink ribbon may be fed and wasted even if the space in the line continues for a long time. Therefore, when the space continues for more than 10 characters, for example, by releasing the pressure on the head unit, it is possible to eliminate wasted ink ribbon, and this can be easily achieved by controlling the solenoid 40.

Furthermore, if characters with different pitches (for example, bi-force and elite) coexist in the l line, it is impossible to suddenly change the carriage movement speed at the character boundary, so printing characters with the same pitch is impossible. It is easy to think of a method in which once the printing is completed, the caliper is returned a distance necessary for a run-up to change the speed, and then the speed is changed and printing is performed.

In addition, in this type of serial thermal printer, it is generally possible to record in a thermal mode using thermal paper without using an ink ribbon winder. By dividing the printing area into four equal parts and dividing the printing area into four head units, it is possible to reduce the reciprocating distance of the carriage and significantly increase the printing speed. This idea can also be applied to a recording mode that uses ink ribbons, and if single-color recording is acceptable, all four ink ribbon cassettes should be of the same color, and the recording areas of each head unit should be aligned. You can also adjust the recording speed.

(Effects of the Invention) As explained above, in the present invention, ink ribbon cassettes of different colors are arranged on a carriage in a predetermined order, and the thermal head, which melts the ink ribbon of each ink ribbon cassette, is set with an ink ribbon force. A control circuit board is also provided in the carriage L to control the operation of pressing the thermal head against the recording paper and releasing the pressure based on the recording signal, so that it is possible to use multiple thermal heads. However, because the number and number of flat cables are small, it does not require a large space compared to conventional single-head printers, and the voltage drop due to head drive current is also reduced. Also, if the circuit for controlling the thermal head is installed on the carriage separately from other control circuits, it will be easier to check the circuit, and replacing the circuit elements on the carriage will be much easier as connecting and disconnecting the connector. Become so.

Furthermore, by adopting such a circuit configuration, the number of transmitted signals can be reduced, so malfunctions of the circuit due to poor contact at the connector portion can be reduced, and reliability can be improved.

[Brief explanation of the drawing]

FIG. 1 is an external perspective view of a serial color thermal printer according to the present invention, FIG. 2 is a perspective view showing the main parts of the serial color thermal printer according to the present invention with the cover removed, and FIG. 3 is a plan view of the carriage section. Figure 4 (a) is a perspective view of the head unit, (b) is a side view of the same head unit, Figure 5 is a partially exploded perspective view of the ink ribbon winding mechanism, and Figure 6 is the ink ribbon shown in Figure 5. 7 is a perspective view showing the arrangement of the sub-control circuit board, FIG. 8 is a plan view of the ink ribbon cassette used in the serial color thermal printer according to the present invention, and FIG. 9 is a view of the paper feed section. FIG. 1O is a front view showing the mechanism, and is a partial perspective view showing the mounting portion of the flat platen of the serial color thermal printer according to the present invention. 1...Printer main body base, 2...Cover, 3...
- Opening/closing lid, 4... Operating unit, 10... Main control circuit board, 20... Carriage part, 21... Housing, 22
~25...Head unit, 30...Paper feed section, 40
... Solenoid, 51... Drive gear, 53... Eyetler gear, 54... Winding gear, 59.76...
・Timing belt, 60...Sub control circuit board i7165 (10) Ward
■ ○! 1 shogun

Claims (1)

[Claims] A plurality of ink ribbon cassettes are loaded in a predetermined order in the recording direction on a reciprocating carriage, a plurality of thermal head units that heat melt the ink ribbons stored in each ink ribbon cassette, and each thermal head unit. A head press release mechanism that presses the head to the recording paper via an ink ribbon and releases the press contact with the recording paper, and a control circuit that controls at least the press release operation of the head pressure release mechanism. Serial color thermal printer.