JPH07178979A - Serial printer - Google Patents

Abstract

PURPOSE:To keep a constant gap even when a print head and a platen are tilted. CONSTITUTION:A microprocessor 37 controls a platen moving section 30 and a carriage moving section 32, measures a distance between the platen and the print head at two points separated in the printing direction on the platen, and stores the obtained result in a platen-ribbon protector bracket distance memory 34. The microprocessor 37 obtains a tilt of the platen from the difference of the distance, controls the platen moving section 30 and the carriage moving section 32 in printing, and moves the platen up and down in accordance with the tilt by moving a carriage unit so as to keep a gap constant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a serial printer, and more particularly to a gap position adjusting device between a print head and a platen.

[0002]

2. Description of the Related Art FIG. 12 is a side view showing a schematic configuration of a serial printer, and FIG. 13 is a front view. 1 is the print head,
Reference numeral 2 is a platen arranged to face the print head 1, and 3 is a ribbon protector bracket attached to the print head 1 so as to face the platen 2.

A feed roller 4 for conveying a medium 5 such as a passbook is driven by a motor (not shown) to rotate the feed roller 4 and feed the clamped medium 5 between the print head 1 and the platen 2. , The medium 5 is moved to the print position. As shown in FIG. 13, the platen 2 extends in a direction orthogonal to the moving direction of the medium 5, and the print head 1 is mounted on the platen 2 by a mechanism (not shown).
It is possible to move in the printing direction along.

At the time of printing in the serial printer having such a structure, the print head 1 is used with a small gap g opened with respect to the platen 2. If the print head 1 is used in a state in which the gap g between the print head 1 and the platen 2 is narrower than an appropriate value, problems such as medium feeding failure and ribbon feeding failure may occur.

If the print head 1 is used in a state where the gap g is wider than an appropriate value, print may be blurred and unclear, or head pin breakage may occur. Therefore, the gap g between the print head 1 and the platen 2 must be managed accurately. In particular, as the printing speed of the printer becomes faster, the pin stroke of the print head 1 becomes shorter, and therefore the proper value of the gap and its allowable range become narrower, and it becomes necessary to perform gap management at a higher level. ing.

As described above, in order to manage the gap g between the print head 1 and the platen 2 in the serial printer, the print head 1 has a structure that can be moved far and far with respect to the plante 2, or vice versa. 2 has a structure in which the print head 1 can be moved far and far, and the gap g can be changed.

[0007]

However, in the conventional serial printer, as shown in FIG. 13, the print head 1 has a platen 2 over the entire area L in the print direction.
And a gap g1 when the print head 1 is located on the side of position 1 which is one end of the platen 2 and a position on the side of position 2 which is the side of the other end. However, even if the gap g2 is equal to the gap g2, the parallelism is ensured by the accuracy of the parts, the assembly variation, or the foreign matter entering between the print head 1, the ribbon protector bracket 3 and the platen 2. I often cannot. Therefore, even if an appropriate gap g1 necessary for printing is provided on the position 1 side, g is increased as the print head 1 moves toward the position 2 side.
When 1 <g2, the gap gradually widens, and when g1> g2, the gap gradually narrows, deviating from the proper gap range required for printing. The gap exceeds the proper range. Then, as described above, there are problems such as medium feeding failure, ribbon feeding failure, unclear printing, and broken head pin.

In order to solve such a problem, FIG.
FIG. 2 is a side view of a serial printer in which the height of the platen 2 with respect to the print head 1 can be finely adjusted. 6 is a rack to which the platen 2 is attached, 7 is a height of the platen 2 when the platen 2 is attached to the rack 6. The eccentric shoulder collar 7 is adjustable, and the height of the platen 2 is finely adjusted by the eccentric shoulder collar 7 so that the parallelism between the print head 1 and the platen 2 can be ensured.

However, even if the height of the platen 2 can be finely adjusted in this way, the parallelism between the print head and the platen is affected by the impact on the serial printer during transportation or the distortion of the place where the serial printer is installed. Change and the deviation from the proper gap range necessary for printing causes problems such as medium feeding failure, ribbon feeding failure, unclear printing, and broken head pin.

The present invention solves the above-described problem that the parallelism between the print head and the platen cannot be ensured when the print head moves, and the print head deviates from the proper gap range required for printing. An object of the present invention is to provide a serial printer capable of detecting a print head and a platen inclination before printing, moving the platen according to the inclination, and always maintaining a constant gap.

Further, according to the present invention, the inclination between the print head and the platen can be detected before printing, and the printing speed can be controlled according to this inclination to prevent print blurring, dot omission, and head pin breakage. The purpose is to provide a serial printer. Furthermore, the present invention establishes the reliability of variable gap control or print speed control by determining the presence or absence of foreign matter when detecting the inclination between the print head and the platen before printing, and at the same time, media breakage or head pin breakage. An object of the present invention is to provide a serial printer capable of preventing the above.

It is another object of the present invention to provide a serial printer capable of constantly maintaining a proper gap required for printing by automatically adjusting the parallelism between the print head and the platen.

[0013]

In order to achieve this object, the present invention is directed to a platen arranged to face a print head, and a gap is adjusted by moving the platen toward and away from the print head. A carriage unit for mounting a print head, a shaft extending along the platen for guiding the movement of the carriage unit, and a drive mechanism for moving the carriage unit along the shaft. In a serial printer provided with a carriage driving means for moving the unit in the printing direction along the platen,
The distance between the print head and the platen is measured at multiple points on the platen, the inclination of the platen is calculated from the difference in the distance between the print head and the platen at these multiple points, and the carriage drive unit is controlled to move the carriage unit along the platen. When the carriage unit moves in the printing direction along the platen by moving the platen driving means in accordance with this inclination to move the platen toward or away from the print head while moving in the printing direction. And a control means for forming a constant gap between the print head and the platen.

In the serial printer, the carriage speed storage means for storing the moving speed of the carriage unit according to the inclination of the platen and the distance between the print head and the platen are measured at a plurality of points on the platen. Inclination of the platen is obtained from the difference in the distance between the print head and the platen in FIG. 1, the moving speed of the carriage unit corresponding to this inclination is read from the carriage speed storing means, and the carriage driving means is based on the read moving speed of the carriage unit. May be provided to control the carriage unit to change the moving speed of the carriage unit.

Further, the distance between the print head and the platen is measured at a plurality of points on the platen, and the inclination of the platen is obtained from the difference in the distance between the print head and the platen at the plurality of points. If it is determined that there is a foreign substance, the operation is stopped if it is determined by measuring the foreign substance when measuring the distance between the print head and the platen. Then, a control means for notifying the operator may be provided.

According to the present invention, the platen driving means is provided with a mechanism for independently moving the left and right sides of the platen, and the distance between the print head and the platen is measured at a plurality of points on the platen. The platen tilt is obtained from the difference in the distance between the print head and the platen, and the platen drive means is controlled according to this tilt to move the platen, thereby providing a control means for parallelizing the print head and the platen. Characterize.

Further, according to the present invention, the carriage height adjusting means for changing the inclination of the shaft for guiding the movement of the carriage unit of the carriage driving means, and the distance between the print head and the platen are measured at a plurality of points on the platen. The inclination of the platen is obtained from the difference in the distance between the print head and the platen at a plurality of positions, and the carriage height adjusting means is controlled according to the inclination to change the inclination of the shaft to make the print head parallel to the platen. A control means is provided.

[0018]

According to the present invention having the above-described structure, the distance between the print head and the platen is measured at a plurality of points on the platen, and the inclination of the platen is obtained from the difference in the distance between the print head and the platen at the plurality of points. When the carriage unit is moved in the printing direction during printing, the platen is moved up and down according to this inclination to keep the gap necessary for printing constant even if the parallelism between the print head and the platen is incorrect. .

Although the gap is kept constant by controlling as described above, the pin stroke of the print head changes when the platen is tilted and the platen is tilted. The moving speed of the carriage unit is read and the moving speed of the carriage unit is changed according to the pin stroke. further,
When calculating the print head and platen tilt, this tilt may have been calculated because the platen itself is tilted, or when measuring the distance between the print head and the platen, the foreign matter was measured and the tilt was erroneously calculated. If it is determined that there is a foreign substance, the operation is stopped to prevent malfunction of the device.

Further, according to the present invention, the distance between the print head and the platen is measured at a plurality of points on the platen, the inclination of the platen is obtained from the difference in the distance between the print head and the platen at the plurality of points, and the inclination is determined according to the inclination. The tilt of the platen to make the print head parallel to the platen. further,
In the present invention, the distance between the print head and the platen is measured at a plurality of points on the platen, the inclination of the platen is obtained from the difference in the distance between the print head and the platen at the plurality of points, and the carriage unit moves according to the inclination. Change the inclination of the shaft guiding the so that the print head and platen are parallel.

[0021]

Embodiments Embodiments will be described below with reference to the drawings. FIG. 1 is a control block diagram of a serial printer showing a first embodiment of the present invention, and FIG. 2 is a side view showing a platen up / down mechanism mounted on the serial printer.
The configuration of the platen up / down mechanism will be described with reference to FIG.

In the drawing, 11 is an up / down (hereinafter referred to as U / D) motor, and a motor gear 12 and a slit disk 13 are fixed to the shaft of this U / D motor 11. Reference numeral 14 denotes a rack to which the platen 2 is attached. The rack 14 supports the platen 2 so that the platen 2 can move toward and away from the print head 1 and can move in the vertical direction. A rack gear portion 14a extending along is provided. The racks 14 are attached to both ends of the platen 2 in the extending direction.

Reference numeral 15a denotes a motor gear 1 of the U / D motor 11.
2 is a large gear that meshes with 2; 15b is a small gear that is coaxial with this large gear 15a; 15c is a large gear that meshes with this small gear 15b; 15d is a small gear that is coaxial with this large gear and that meshes with the rack gear portion 14a of the rack 14. The driving force generated by the U / D motor 11 is transmitted to the rack 14 by these gear groups, and the rotational movement of the U / D motor 11 is converted into the vertical movement of the rack 14. The rack 14 is the platen 2
Since they are attached to both ends of the gear 15c, 1g in order to transmit the driving force to the other rack 14,
A shaft extends from 5d along the platen 2, and a small gear is attached to the shaft so that the gear is attached to the rack 14
Is engaged with the rack gear portion 14a. This allows
The driving force is simultaneously transmitted to the racks 14 on both the left and right sides, and the platen 2 can be moved up and down while maintaining the parallel state.

Reference numeral 16 is a photosensor for detecting the rotation amount of the slit disk 13,
3 is provided with a plurality of slits along the circumferential direction, and the U / D motor 1 is provided by detecting the slits with the photosensor 16 and counting the number of the slits.
The rotation amount of 1 can be recognized, whereby the position of the platen 2 that moves up and down by rotating the U / D motor 11 can be managed.

Reference numeral 17 denotes a contact detection sensor, which detects that the platen 2 or the medium 5 has come into contact with the lower surface of the ribbon protector bracket 3. Next, the operation of the up / down mechanism of the platen 2 having the above configuration will be described. As an initial operation of the printer of the auto gap method, an operation for storing the distance from the initial DOWN position of the platen 2 to the ribbon protector bracket 3 as basic data for the subsequent medium thickness measurement is performed.

That is, by sending a forward signal to the U / D motor 11, the U / D motor 11 is rotated in a predetermined direction so that the platen 2 at an initial position apart from the ribbon protector bracket 3 to a certain extent is moved to the ribbon protector. Move in the direction of the bracket 3. When the forward signal is continuously sent to the U / D motor 11, the space between the platen 2 and the ribbon protector bracket 3 becomes narrower, and finally the platen 2 and the ribbon protector bracket 3 come into contact with each other. The contact between the platen 2 and the ribbon protector bracket 3 is detected by the contact detection sensor 17, which stops the rotation of the U / D motor 11.

At this time, the feedback pulse from the photo sensor 16 counts the number of slits detected before the U / D motor 11 starts rotating and the platen 2 comes into contact with the ribbon protector bracket 3. Is stored as the distance from the initial position of the platen 2 to the ribbon protector bracket 3, and then,
The U / D motor 11 is rotated in the opposite direction to return the platen 2 to the initial position.

Next, when the medium is conveyed by the feed roller 4 and positioned between the print head 1 and the platen 2,
The thickness of this medium is detected. That is, the U / D motor 1
By sending a forward signal to 1, the U / D motor 11 is rotated in a predetermined direction, and the platen 2 at the initial position is moved in a direction approaching the medium.

When the forward signal is continuously sent to the U / D motor 11, the medium is pushed up by the platen 2 and comes into contact with the ribbon protector bracket 3, which is detected by the contact detection sensor 17 to rotate the U / D motor 11. Stopped. At this time, the feedback pulse from the photo sensor 16 counts the number of slits detected until the U / D motor 11 starts rotating and the medium comes into contact with the ribbon protector bracket 3. As described above, the distance between the initial position of the platen 2 and the ribbon protector bracket 3 is stored, and the slit detected before the U / D motor 11 starts rotating and the platen 2 contacts the ribbon protector bracket 3 is detected. The difference from the counted number when the number is counted is obtained, and this difference is stored as the thickness of the medium.

Then, an optimum gap g corresponding to the medium thickness is set, the U / D motor 11 is rotated by a predetermined amount in the opposite direction to the above, and the platen 2 is moved away from the ribbon protector 3. After the gap g is provided between the medium and the ribbon protector bracket 3, the U / D motor 1
1 is stopped and the platen 2 is fixed. FIG. 3 is a perspective view showing the main configuration of the serial printer.

In the figure, 18 is a carriage unit on which the print head 1 is mounted. 19 is a belt for moving the carriage unit 18 in the spacing direction, 2
Reference numeral 0 is a DC motor for driving the belt 19, 21 is a main shaft for supporting the carriage unit 18 and for guiding the movement of the carriage unit 18, and 22 is a sub-shaft for guiding the movement of the carriage unit 18. Is.

Reference numeral 23 is a slit disk fixed on the shaft of the DC motor 20, and is provided with a plurality of slits in the circumferential direction. Reference numeral 24 is a photosensor for detecting the slits of the slit disk 23. By counting the number of slits, the rotation amount of the DC motor 20 can be recognized, and by this, the carriage unit that moves by the rotation of the DC motor 20. It is possible to manage 18 positions, moving distances, moving speeds, and the like.

Next, a first embodiment of the present invention will be described with reference to the control block diagram of FIG. In the figure, reference numeral 30 denotes a platen moving unit, which is composed of the U / D motor 11, the slit disk 13, the photo sensor 16 and the contact detection sensor 17 described in FIG. A platen position management control unit 31 controls the U / D motor 11 based on the detection information from the photo sensor 16 and the contact detection sensor 17 of the platen moving unit 30.

Reference numeral 32 denotes a carriage moving unit, which is composed of the DC motor 20, the slit disk 23 and the photo sensor 24 described with reference to FIG. Reference numeral 33 denotes a carriage position management control unit, and this carriage position management control unit 33 uses the D / C motor 2 based on detection information from the photo sensor 24 of the carriage moving unit 32.
Control 0.

A platen-ribbon protector bracket distance storage unit 34 stores at least two distances from the initial position of the platen 2 to the ribbon protector bracket 3 in the platen-ribbon protector bracket distance storage unit 34. . Reference numeral 35 is a platen gap storage unit, and the platen gap storage unit 35 stores the gap and the like set according to the medium thickness by the operation described in FIG.

Reference numeral 36 denotes a platen basic movement amount storage unit. The platen basic movement amount storage unit 36 previously obtains the medium thickness of the medium as described in FIG. In order to provide a gap between the medium and the ribbon protector bracket 3, data or the like indicating the amount of movement of the platen 2 according to the medium thickness is stored. Reference numeral 37 denotes a microprocessor for controlling each of the above-mentioned components, which controls the serial printer by exchanging data between the above-mentioned units and executing arithmetic processing in the arithmetic unit 38.

FIG. 4 is a front view of the serial printer showing the position of the print head 1. The operation of the first embodiment having the above-mentioned construction will be described below. First, as an initial operation, the microprocessor 37 causes the carriage moving unit 32 to
Is controlled to move the carriage unit 18 to move the print head 1 to the position 1 shown in FIG.

That is, a signal for rotating the D / C motor 20 is sent and the rotation of the slit disk 23 is detected by the photo sensor 24, whereby the carriage unit 1 is detected.
8 position is monitored and print head 1 is positioned at position 1. Next, the microprocessor 37 controls the platen moving unit 30 to move the platen 2 and obtains the distance from the platen at the initial position to the ribbon protector bracket 3.

That is, a forward signal is sent to the U / D motor 11 to rotate it, and the platen 2 at the initial position is moved toward the ribbon protector bracket 3. U / D
When the forward signal is continuously sent to the motor 11, the distance between the platen 2 and the ribbon protector bracket 3 becomes narrower, and finally the platen 2 and the ribbon protector bracket 3 come into contact with each other. The contact between the platen 2 and the ribbon protector bracket 3 is detected by the contact detection sensor 17, which causes the U / D motor 11 to move.
The rotation of is stopped.

At this time, the microprocessor 37 uses the feedback pulse from the photo sensor 16 to generate U
/ D The motor 11 starts rotating and counts the number of slits detected until the platen 2 contacts the ribbon protector bracket 3.
The distance g1 from the initial position of the platen 2 to the ribbon protector bracket 3 is stored in the platen-ribbon protector bracket distance storage unit 34, and then the U / D motor 11 is rotated in the opposite direction to the above.
Return the platen 2 to the initial position.

Next, the microprocessor 37 controls the carriage moving unit 32 to move the carriage unit 18 to move the print head 1 from the position 1 to the position 2 on the opposite side. As described above, the platen moving unit 30 is controlled to move the platen 2, and the distance g2 from the platen 2 at the initial position in the position 2 to the ribbon protector bracket 3 is obtained, and this is stored as the distance between the platen and the ribbon protector bracket. It is stored in the unit 34.

Then, the microprocessor 37 can determine how much the parallelism of the platen 2 is deviated from the difference between g1 and g2 stored in the platen-ribbon protector bracket distance storage section 34 as described above. it can. That is, the distance between the platen 2 and the ribbon protector bracket 3 at the position 1 is g1 mm, the distance between the platen 2 and the ribbon protector bracket 3 at the position 2 is g2 mm, the distance between the position 1 and the position 2 is L mm, and the platen 2 is operated U If the resolution of the / D motor 11 is Amm and the resolution of the D / C motor 20 that operates the carriage unit 18 is Bmm,
The difference H in height between the platen 2 on the left and right is obtained by the following equation (1).

[0043]

## EQU1 ## H = g1-g2 (1) Note that when H in the formula (1) is positive, g1> g2, and when H is negative, g1 <g2. It is possible to determine the direction of inclination. Then U
Since the resolution of the / D motor 11 is Amm, the difference between the heights of the platen 2 on the left and right sides is represented by the number of pulses P1 as shown in the following equation (2).

[0044]

## EQU2 ## P1 = H / A (2) If the distance L between position 1 and position 2 is represented by the number of pulses P2 in accordance with the resolution of the DC motor 20, the resolution of this DC motor 20 is Bmm. Therefore, P2 is expressed by the following equation (3).

[0045]

[Equation 3] P2 = L / B (3) Therefore, the pulse number P3 is obtained by the following equation (4), and the U / D motor 11 is driven by one pulse every time the DC motor 20 is driven by P3 pulses. By driving, the distance between the platen 2 and the ribbon protector bracket 3 can be kept constant.

[0046]

## EQU00004 ## P3 = P2 / P1 (4) In the expression (1), when H = 0, it can be determined that the platen 2 is not tilted. In this case, U /
The D motor 11 is not driven. For example, the distance between the platen 2 and the ribbon protector bracket 3 at position 1 is g1 = 5 mm, and the distance between the platen 2 and the ribbon protector bracket 3 at position 2 is g2 = 5.5.
mm, the distance between position 1 and position 2 is L = 200
mm, the resolution of the U / D motor 11 that operates the platen 2 is A = 0.1 mm, and the resolution of the D / C motor 20 that operates the carriage unit 18 is B = 0.2 mm. The difference H is calculated by the above-mentioned formula (1) and becomes H = -0.5 mm. Since H is negative, the platen 2 in FIG.
Can be determined to be in a state of falling to the left.

When the difference H between the left and right heights of the platen 2 is expressed by the number of pulses P1 from the above equation (2), the U / D motor 1
Since the resolution of 1 is 0.1 mm, P1 = −5 pulses. Also, the distance L between position 1 and position 2
Is represented by the number of pulses P2 in accordance with the resolution of the DC motor 20, P2 = 1000 pulses from the above equation (3).

Then, from the equation (4), 1000 pulses, which is the distance between the position 1 and the position 2, is divided by -5 pulses, which is the difference in height between the platen 2 on the left and right,
The number of pulses P3 = −200 is obtained. Therefore, in FIG. 4, the D / C is set so that the carriage unit 18 moves to the left.
When rotating the motor 20, set the D / C motor 20 to 2
The U / D motor 11 is rotated by 1 pulse so that the platen 2 is moved upward every time it is rotated by 00 pulses, and conversely, the D / D is moved so that the carriage unit 18 is moved rightward.
When the C motor 20 is rotated, every time the D / C motor 20 is rotated by 200 pulses, the U / D motor 11 is rotated by 1 pulse so that the platen 2 moves downward.

As described above, when the carriage unit 18 is moved left and right for printing, the carriage unit 1
Every time 8 moves by 200 pulses of the DC motor 20, the platen 2 is moved up and down by 1 pulse of the U / D motor 11 so that even if the platen 2 is tilted, it is necessary for printing set according to the medium thickness. The large gap g can be kept constant.

The distance g1 between the platen 2 and the ribbon protector bracket 3 at the position 1 and the distance g2 between the platen 2 and the ribbon protector bracket 3 at the position 2 are determined by detecting the slit disk 13 with the photosensor 16. Since this is represented by the number of pulses according to the resolution of the U / D motor 11, if the above example is represented by a general formula, the inclination of the platen 2: P1 = g1
-G2, distance between position 1 and position 2: P2,
Platen 2 up / down timing: P3 = P2 /
It becomes P1.

As a result, the carriage unit 18 becomes P
The inclination of the platen 2 is moved up and down by one pulse according to the sign of the inclination: P1 of the platen 2 every time it moves by 3 pulses, so that the inclination of the platen 2 peculiar to each machine is smoothly corrected. It is possible to stably set the gap g required for printing, which is set according to the medium thickness, within an appropriate allowable range.

In this embodiment, the platen side is moved in order to make the gap between the print head and the platen variable, but it is also possible to move the carriage unit side. Further, in the present embodiment, the inclination of the platen is obtained based on the difference in height between two places on the left and right. You may ask.

FIG. 5 is a control block diagram of a serial printer showing a second embodiment of the present invention. In the second embodiment, the structure of the serial printer is the same as that described with reference to FIGS. 2 and 3, and in FIG. 5, the platen moving unit 30, the platen position management control unit 31, and the carriage moving unit 32 are used. The carriage position management control unit 33, the platen-ribbon protector bracket distance storage unit 34, the platen gap storage unit 35, and the platen basic movement amount storage unit 36 are the same as those described in the first embodiment with reference to FIG. The description is omitted here.

In FIG. 5, reference numeral 38 denotes a carriage speed storage unit, and this carriage speed storage unit 38 has a platen 2
A data table for gradually changing the speed of the DC motor 20 is formed so that the moving speed of the carriage unit 18 can be obtained according to the inclination of. That is, when the platen 2 is not tilted, the moving speed of the carriage unit 18 is set to the maximum speed, and when the tilt of the platen 2 is small, it is slightly slower than this, and as the tilt of the platen 2 becomes larger, it gradually becomes slower. A data table has been created.

Reference numeral 39 denotes a microprocessor for controlling each of the above-mentioned components, which controls the serial printer by exchanging data between the above-mentioned units and executing arithmetic processing in the arithmetic unit 38. FIG. 6 is a front view of a serial printer showing the concept of the second embodiment of the present invention, and the second embodiment will be described below.

FIG. 6A shows a state in which the platen 2 is parallel to the print head 1. By providing a gap g required for printing in accordance with the thickness of the medium 5, the print head 1
The pin stroke of the pin (not shown) is g, and printing can be performed with an appropriate stroke. However, as shown in FIG. 5B, when the platen 2 is tilted with respect to the print head 1, the platen 2 is tilted even if the gap g necessary for printing is provided according to the thickness of the medium 5. Therefore, the pin stroke of the print head 1 is g + P,
The length P extends beyond the pin stroke g of the main body.
According to the first embodiment, the gap can be kept constant even if the platen 2 is tilted, so that g + P is constant, but the larger the tilt of the platen 2, the larger the value of P becomes. In other words, the pin stroke becomes longer,
This may cause problems such as print faintness, missing dots, and broken pins.

Therefore, in the second embodiment, the printing speed according to the pin stroke is obtained by changing the printing speed according to the inclination of the platen 2. That is, after setting the gap g according to the medium thickness, the microprocessor 39 causes the carriage moving unit 32 to move.
To move the carriage unit 18 to position the print head 1 at the position 1, and to move the platen moving unit 3
The platen 2 is moved by controlling 0, and the distance g1 from the platen 2 at the initial position in position 1 to the ribbon protector bracket 3 is obtained from the output of the photosensor 16 at this time, and this is determined as the platen-ribbon protector bracket. It is stored in the distance storage unit 34.

Next, the microprocessor 39 moves the print head 1 from the position 1 to the opposite position 2 and further moves the platen 2 to move the platen 2 from the platen 2 in the initial position in the position 2 to the ribbon protector bracket. The distance g2 up to 3 is calculated, and this is stored in the platen-ribbon protector bracket distance storage unit 34.
Remember.

Then, the microprocessor 39 calculates the difference between g1 and g2 stored in the platen-ribbon protector bracket distance storage unit 34 as described above, and as described in the first embodiment, the platen 2 The tilt of the platen 2 is calculated from the tilt of the carriage unit 18 and the pulse of the carriage unit 18 is moved up and down. Thereby, as described in the first embodiment, even if the platen 2 is inclined, the gap g required for printing set according to the medium thickness can be made constant. In the second embodiment, the microprocessor 39 reads the data indicating the moving speed of the carriage unit 18 corresponding to the inclination of the platen 2 from the carriage speed storage unit 38.

As described above, the carriage speed storage unit 38 stores data that gradually decreases the moving speed of the carriage unit 18 as the inclination of the platen 2 increases. Based on the data read from the carriage speed storage unit 38 via the management control unit 33, the carriage moving unit 3
Control 2

That is, as the inclination of the platen 2 becomes larger, the pin stroke of the print head 1 becomes longer,
Since the moving speed of the carriage unit 18 is gradually decreased as the inclination of the platen 2 increases, a printing speed corresponding to the pin stroke can be obtained, and the moving speed of the carriage unit 18 decreases as the pin stroke increases. It is possible to prevent the occurrence of troubles such as print faintness, missing dots, and broken pins.

In this embodiment, the platen side is moved in order to make the gap between the print head and the platen variable, but it is also possible to move the carriage unit side. FIG. 7 is a control block diagram of a serial printer showing a third embodiment of the present invention. In addition, in the third embodiment, the structure of the serial printer is the same as that described in FIGS. 2 and 3, and in FIG. 7, the platen moving unit 30, the platen position management control unit 31, and the carriage moving unit 32 are shown. The carriage position management control unit 33, the platen-ribbon protector bracket distance storage unit 34, the platen gap storage unit 35, the platen basic movement amount storage unit 36, and the carriage speed storage unit 38 are the same as those in the first embodiment shown in FIGS. The embodiment is similar to that described with reference to FIG. 5, and therefore the description thereof is omitted here. In FIG. 7, a display unit 40 displays information for informing the operator that a failure has occurred in the device.

Reference numeral 41 denotes a microprocessor for controlling each of the above-mentioned constituent elements, which controls the serial printer by exchanging data between the above-mentioned respective sections and executing arithmetic processing in the arithmetic section 38. The operation of the third embodiment having the above configuration will be described below. First, the microprocessor 41
Is similar to the procedure described in the first embodiment, the distance g1 between the platen 2 and the ribbon protector bracket 3 at position 1 and the platen 2 at position 2
The distance g2 between the ribbon protector bracket 3 and the ribbon protector bracket 3 is obtained.

That is, the microprocessor 41 controls the carriage moving unit 32 to move the carriage unit 18 and move the print head 1 to the position 1 shown in FIG. Next, the microprocessor 41 controls the platen moving unit 30 to move the platen 2 so that the ribbon protector bracket 3 moves from the platen 2 in the initial position.
Up to the position 1 at position 1 and the platen-ribbon protector bracket distance storage unit 34
Remember.

Similarly, the microprocessor 41 controls the carriage moving unit 32 to control the carriage unit 18.
To move the print head 1 from the position 1 to the opposite position 2, and the microprocessor 41 controls the platen moving unit 30 to move the platen 2 to the initial position as described above. A distance g2 at a position 2 from a certain platen 2 to the ribbon protector bracket 3 is calculated and stored in the platen-ribbon protector bracket distance storage unit 34.

The microprocessor 41 previously recognizes the distance L between the position 1 and the position 2, and the difference between g1 and g2 stored in the platen-ribbon protector bracket distance storage section 34 and the position 1 are stored.
Using the distance L between the position 2 and the position 2, the tilt angle Q1 of the platen 2 is calculated by the following equation (5).

[0067]

## EQU5 ## Q1 = (g1-g2) / L (5) Here, the position 3 is set in advance to a position facing the inner side from the position 1 by an arbitrary distance, and the position 3
The position 4 is set at a position different from the position 2 and inward from the position 2 by an arbitrary distance, and the microprocessor 41 operates the distance g3 between the platen 2 and the ribbon protector bracket 3 at the position 3 in the same manner as described above. Also, a distance g4 between the platen 2 and the ribbon protector bracket 3 at the position 4 is obtained, and this is calculated as the platen-ribbon protector bracket distance storage unit 34.
Remember.

The microprocessor 41 previously recognizes the distance L2 between the position 3 and the position 4, and the difference between g3 and g4 stored in the platen-ribbon protector bracket distance storage unit 34 and the position 3 are stored. Using the distance L2 from the position 4, the tilt angle Q2 of the platen 2 at another point is calculated from the equation (6) shown below.

[0069]

## EQU6 ## Q2 = (g3-g4) / L2 (6) Usually, from the difference between the tilt angle obtained from the height difference between two points on the platen 2 and the height difference between the other two points. Since the calculated tilt angles are almost the same, the microprocessor 41 compares the Q1 and Q2, and if the difference between the two values is within a predetermined allowable value, the platen 2 is tilted. Judgment is made to move the platen 2 up and down in accordance with the movement of the carriage unit 18 described in the first embodiment to keep the gap constant, and further, the inclination of the platen 2 described in the second embodiment. According to the above, the operation of changing the moving speed of the carriage unit 18 is performed.

On the other hand, if the tilt angle obtained from the height difference between two points on the platen 2 is different from the tilt angle obtained from the difference between the heights of two other points, the platen 2 is moved. When the distance between the platen 2 and the ribbon protector bracket 3 is calculated by moving the platen 2 and the ribbon protector bracket 3, it is considered that the correct distance could not be calculated because of a foreign substance between the platen 2 and the ribbon protector bracket 3. , The microprocessor 41 compares Q1 and Q2, and if the difference between the two values exceeds a predetermined allowable value, the microprocessor 41 determines that there is a foreign object somewhere in positions 1 to 4, and the display unit 40 An error display will be displayed to inform the operator of the device abnormality, and
Stop the operation of the device.

As a result, the carriage unit 18 is originally
Although the platen 2 is parallel to the movement of the platen 2, it is erroneously detected that the platen 2 is tilted due to the presence of a foreign substance, and the platen 2 is moved along with the movement of the carriage unit 18 described in the first embodiment. The operation of vertically moving the platen 2 is erroneously performed to change the gap, or the operation of changing the moving speed of the carriage unit 18 in accordance with the inclination of the platen 2 described in the second embodiment is erroneously performed. It is possible to prevent the moving speed of 18 from being slowed.

In the third embodiment, the inclination obtained from the height difference between the positions 1 and 2 and the positions 3 and 4 set inside the inclination.
Compared with the slope obtained from the difference in height between
In addition to this, by comparing the inclinations at a plurality of positions, such as between position 1 and position 4, between position 2 and position 3, the microprocessor 41 can detect which position the foreign matter is in, and display By displaying the location of the foreign matter on the section 40, the maintenance work of the operator can be facilitated.

FIG. 8 is a control block diagram of a serial printer showing a fourth embodiment of the present invention, and FIG. 9 is a side view showing a platen up / down mechanism mounted on the serial printer according to the fourth embodiment. First, with reference to FIG.
The platen up / down mechanism in this embodiment will be described. In FIG. 9, the print head 1, platen 2, ribbon protector bracket 3, feed roller 4, rack 14, rack gear portion 14a, contact detection sensor 17, carriage unit 18, main shaft 21, etc.
The embodiment is similar to that described with reference to FIGS.

In the figure, 42a is an up / down (hereinafter referred to as U / D) motor, which is the U / D motor 42a.
The shaft of the motor gear 43a and the slit disk 44a
Are fixed respectively. The U / D motor 42a is
Although not shown in the drawing, the U / D is provided so as to correspond to one rack 14 of the racks 14 attached to both ends of the platen 2 in the extending direction and overlaps with the motor 42a, but not shown. A motor 42b is provided, and a motor gear 43b is fixed to the shaft of the U / D motor 42b.

45a is a large gear meshing with the motor gear 43a of the U / D motor 42a, 46a is a small gear coaxial with this large gear 45a, 47a is a large gear meshing with this small gear 46a, and 48a is coaxial with this large gear 47a. , A small gear that meshes with the rack gear portion 14a of the rack 14, the driving force generated by the U / D motor 42a is transmitted to the rack 14 by these gear groups, and the rotational movement of the U / D motor 42a is changed to the vertical movement of the rack 14. To be converted.

The racks 14 are attached to both ends of the platen 2, and the driving force of the U / D motor 42b provided corresponding to the racks 14 is applied to the other rack 14.
In order to transmit the driving force to the gear group, a gear group having the same configuration as described above, that is, the motor gear 43 of the U / D motor 42b.
b, a small gear 46b coaxial with the large gear 45b, and a large gear 47 that meshes with the small gear 46b.
b, a small gear 48b coaxial with the large gear 47b and engaged with the rack gear portion 14a of the rack 14 is provided.

As a result, the U / D motors 42a, 42b
The driving force is simultaneously transmitted to the racks 24 on both the left and right sides by simultaneously driving the platen 2 and the platen 2 can be moved up and down while maintaining the parallel state.
By driving either one of 2a and 42b, the driving force can be transmitted only to one rack 14 and the inclination of the platen 2 can be changed.

Reference numeral 49a is a photosensor for detecting the rotation amount of the slit disk 44a. The slit disk 44a is provided with a plurality of slits along its circumferential direction. By detecting and counting the number of the slits, the rotation amount of the U / D motor 42a can be recognized. This makes U / D
When rotating the motors 42a and 42b in synchronization,
It is possible to control the position of the entire platen 2 that moves up and down, and to control the tilt of the platen 2 by controlling the position of one side of the platen 2 by rotating only the U / D motor 42a. Is possible.

The operation of the fourth embodiment will be described below with reference to the control block diagram of FIG. In addition, in FIG.
Is a microprocessor for controlling each component, which controls the serial printer by exchanging data between the above-mentioned units and executing arithmetic processing in the arithmetic unit 38. Further, 51 is a platen moving part, and this platen moving part 51 has the above-mentioned left and right U / D motors 42a, 42b,
The microprocessor 5 includes a slit disk 44a, a photo sensor 49a, and a contact detection sensor 17.
0 can control the U / D motors 42a and 42b to rotate in synchronization, and can rotate only the U / D motor 42a whose rotation is detected by the photo sensor 49a. .

Platen position management control unit 31, carriage moving unit 32, carriage position management control unit 33, platen-ribbon protector bracket distance storage unit 34, platen gap storage unit 35, and platen basic movement amount storage which are other components. Since the part 36 is the same as that described in the first embodiment shown in FIG. 1, the description thereof is omitted here.

First, as an initial operation for obtaining the parallelism of the platen, the microprocessor 50 controls the carriage moving unit 32 to move the carriage unit 18 and move the print head 1 to the position 1 shown in FIG. . That is, a signal for rotating the D / C motor 20 is sent and the slit disk 23 is detected by the photo sensor 24.
The position of the carriage unit 18 is monitored by detecting the rotation of the print head 1, and the print head 1 is positioned at the position 1.

Next, the microprocessor 50 controls the platen moving part 51 to move the platen 2 and obtains the distance from the platen at the initial position to the ribbon protector bracket 3 at the position 1. That is, U
A forward signal is sent to both the / D motors 42a and 42b to rotate them in synchronism with each other, and the platen 2 in the initial position is moved toward the ribbon protector bracket 3.

When the forward signal is continuously sent to the U / D motors 42a and 42b, the distance between the platen 2 and the ribbon protector bracket 3 becomes narrower until the platen 2 and the ribbon protector bracket 3 come into contact with each other. The contact between the platen 2 and the ribbon protector bracket 3 is detected by the contact detection sensor 17, which stops the rotation of the U / D motors 42a and 42b.

At this time, the microprocessor 50 receives the feedback pulse from the photo sensor 49a,
The number of slits detected until the U / D motor 42a starts rotating and the platen 2 contacts the ribbon protector bracket 3 is counted, and the counted number is counted from the initial position of the platen 2 in the position 1 to the ribbon protector bracket 3 Is stored in the platen-ribbon protector bracket distance storage unit 34 as a distance g1 up to and then the U / D motors 42a and 42b are rotated in the opposite direction to return the platen 2 to the initial position.

Next, the microprocessor 50 controls the carriage moving unit 32 to move the carriage unit 18 to move the print head 1 from the position 1 to the position 2 on the opposite side, and further, the microprocessor 50 operates as described above. As described above, the platen moving unit 51 is controlled to move the platen 2 to obtain the distance g2 from the platen 2 at the initial position in position 2 to the ribbon protector bracket 3, and store this as the distance between the platen and the ribbon protector bracket. It is stored in the unit 34.

Then, the microprocessor 50 can determine how much the parallelism of the platen 2 is deviated from the difference between g1 and g2 stored in the platen-ribbon protector bracket distance storage section 34 as described above. it can. That is, the microprocessor 50 is a platen-
The g1 and g2 stored in the ribbon protector inter-bracket distance storage unit 34 are read out to obtain the difference between g1 and g2. When there is no difference, it can be determined that the platen 2 is parallel to the carriage unit 18, and when there is a difference, it can be determined that the platen 2 is tilted.

If there is a difference between g1 and g2, U / is set so that this difference can be eliminated and g1 = g2.
The rotation amount of the D motor 42a is obtained. That is, the distances g1 and g2 from the platen 2 at the initial position to the ribbon protector bracket 3 are obtained as the number of pulses by counting the slits of the slit disk 44a. For example, when g1 = P10 pulses and g2 = P20 pulses are set. Then, the difference between g1 and g2 P30 pulse = P10−P20
By determining the above, g1 = g2 can be obtained by rotating the U / D motor 42a by P30 pulses. In addition,
The rotation direction of the U / D motor 42a at this time is g1 and g
It depends on the sign of the difference from 2.

Thus, the distance g1 from the platen 2 to the ribbon protector bracket 3 at position 1
And the distance g2 from the platen 2 to the ribbon protector bracket 3 at the position 2 is different, the microprocessor 50 eliminates this difference and obtains the rotation amount of the U / D motor 42a such that g1 = g2. U /
The D motor 42b is not rotated, and only the U / D motor 42a is rotated in the predetermined direction by this rotation amount.

As a result, the platen 2 becomes parallel to the carriage unit 18, and thereafter, the operation for setting the gap g according to the medium thickness required for printing is continued. As an initial operation of the automatic gap setting, an operation for storing the distance from the initial DOWN position of the platen 2 to the ribbon protector bracket 3 as basic data for subsequent medium thickness measurement is performed.

That is, the microprocessor 50 is U /
By sending a forward signal to the D motors 42a and 42b, the U / D motors 42a and 42b are rotated in synchronization with each other in a predetermined direction, and the platen 2 at an initial position apart from the ribbon protector bracket 3 to a certain extent is moved to the ribbon protector. Move in the direction of the bracket 3. U / D motor 42
If a forward signal is continuously sent to a and 42b, the distance between the platen 2 and the ribbon protector bracket 3 becomes narrower until the platen 2 and the ribbon protector bracket 3 come into contact with each other. The contact between the platen 2 and the ribbon protector bracket 3 is detected by the contact detection sensor 17, which causes the microprocessor 50 to stop the rotation of the U / D motors 42a and 42b.

At this time, the number of slits detected by the feedback pulse from the photo sensor 49a until the U / D motor 42a starts rotating and the platen 2 comes into contact with the ribbon protector bracket 3 is counted. Is stored as the distance from the initial position of the platen 2 to the ribbon protector bracket 3, and then the U / D motors 42a and 42b are rotated in the opposite direction to return the platen 2 to the initial position.

Next, when the medium is conveyed by the feed roller 4 and positioned between the print head 1 and the platen 2,
The thickness of this medium is detected. That is, the microprocessor 50 sends a forward signal to the U / D motors 42a and 42b to rotate the U / D motors 42a and 42b synchronously in a predetermined direction, so that the platen 2 in the initial position approaches the medium. Move in the direction.

When the forward signal is continuously sent to the U / D motors 42a and 42b, the medium is pushed up by the platen 2 and comes into contact with the ribbon protector bracket 3, which is detected by the contact detection sensor 17 and the microprocessor 50 causes the U / D to move to U / D. The rotations of the D motors 42a and 42b are stopped. At this time, the number of slits detected by the feedback pulse from the photo sensor 49a until the U / D motor 42a starts rotating and the medium comes into contact with the ribbon protector bracket 3 is counted. As described above, as a distance stored from the initial position of the platen 2 to the ribbon protector bracket 3, the slit detected before the U / D motor 42a starts rotating and the platen 2 contacts the ribbon protector bracket 3 The difference from the counted number when the number is counted is obtained, and this difference is stored as the thickness of the medium.

Then, the microprocessor 50 sets the optimum gap g according to the medium thickness from the data stored in the platen basic movement amount storage unit 36, and the U / D motor that forms the gap g. 42a, 42b
The U / D motors 42a and 42b are rotated by a predetermined amount in the opposite direction to move the platen 2 in a direction away from the ribbon protector 3 and the gap between the medium and the ribbon protector bracket 3 is calculated. After providing g, U
/ D motor 42a, 42b is stopped and the platen 2 is fixed.

As a result, the gap g required for printing is formed in accordance with the thickness of the medium, and printing is possible. At this time, as described above, the platen 2 is made parallel to the print head 1. Since the position of the platen 2 is adjusted, the gap g can be kept constant over the entire area even if the print head 1 moves for printing. Although the mechanism for vertically moving the platen 2 is used in the fourth embodiment, a mechanism for vertically moving the carriage unit 18 side may be used. Further, not only the U / D motor 42a but also the slit disk and the photosensor may be mounted coaxially with the U / D motor 42b, and the mechanism may be adjusted either left or right.

FIG. 10 is a control block diagram of a serial printer showing a fifth embodiment of the present invention, and FIG. 11 is a perspective view of a serial printer having a carriage unit height adjusting mechanism. First, referring to FIG. The height adjusting mechanism will be described. In the serial printer of FIG. 11, the print head 1, the platen 2, the ribbon protector bracket 3, the carriage unit 18, the main shaft 21, and the sub shaft 22 are the same as those described in each of the above embodiments, and This serial printer is provided with the platen up / down mechanism described in the first embodiment with reference to FIG. 2 and moves the platen 2 up and down with respect to the print head 1 to make the gap g variable and It is possible to move the carriage unit 18 carrying the print head 1 in the printing direction along the platen 2 by the mechanism described in 3.

In FIG. 11, reference numeral 52 is a stepping motor which generates a driving force for moving the carriage unit 18 up and down, and a motor gear 53 is attached to the shaft. 54 is a gear that meshes with this motor gear 53, and 55
Is a gear that meshes with this gear 54, and the main shaft 21 whose outer peripheral surface supports the carriage unit 18.
A cam that abuts on one end side thereof, 57 is a shaft connecting the cam 56 and the gear 55,
The diameter is changed by rotating around the shaft 57, and the one end side of the main shaft 21 can be pushed down by rotating in the direction of increasing the diameter.

Reference numerals 58a and 58b are arms for supporting both ends of the main shaft 21, and 59a and 59b are springs for lifting the main shaft 21 upward through the arms 58a and 58b, respectively. The main shaft 21 is lifted by the spring 59a via the arm 58a.
When the diameter of the cam 56 increases due to the rotation of the cam 56, the main shaft 21 is pushed down against the spring 59a. When the diameter decreases, the spring 59a causes the main shaft 21 to move to the cam 56. Since it is pressed, the main shaft 21 is lifted by the spring 59a.

The other end of the main shaft 21 is lifted by a spring 59b via an arm 58b and pressed by a frame (not shown) so as not to move up and down, whereby the cam 56 rotates. By doing so, the inclination of the main shaft 21 can be changed, and the height of the carriage unit 18 guided by the main shaft 21 with respect to the platen 2 can be changed to change the gap.

Reference numeral 60 denotes a slit disk which is arranged coaxially with the cam 56 and the gear 55 and which rotates in synchronization with the rotation thereof. Reference numeral 61 denotes a photosensor for detecting the rotation amount of the slit disk 60. Is provided with a plurality of slits along the circumferential direction thereof, and by detecting the slits with the photo sensor 61 and counting the number of the slits, the rotation amount of the cam 56 can be recognized. By rotating the cam 56, it is possible to manage the position, the amount of movement, etc. of the carriage unit 18 that moves up and down.

The operation of the fifth embodiment will be described below with reference to the control block diagram of FIG. In FIG. 10, reference numeral 62 denotes a microprocessor for controlling each component, which controls the serial printer by exchanging data between the above-mentioned units and executing arithmetic processing in the arithmetic unit 38. Further, 63 is a carriage moving part, and this carriage moving part 63 is the carriage unit 1 described in FIG.
DC motor 20 for moving 8 in the printing direction, slit disk 23 for managing the printing direction position and movement amount of carriage unit 18, photosensor 24, and stepping motor 52 for moving carriage unit 18 in the vertical direction. And carriage unit 18
It is composed of a slit disk 60 and a photo sensor 61 for controlling the vertical position and the amount of movement.

Platen moving unit 3 which is another component
0, the platen position management control unit 31, the carriage position management control unit 33, the platen-ribbon protector bracket distance storage unit 34, the platen gap storage unit 35, and the platen basic movement amount storage unit 36 in the first embodiment shown in FIG. The description is omitted here because it is similar to that described.

First, when the printer is powered on, the microprocessor 62 controls the stepping motor 52 to rotate the stepping motor 52 in a predetermined direction to move the main shaft 21 to the initial position, The rotation of the stepping motor 52 is stopped to bring it into a holding state. The rotation of the stepping motor 52 is controlled by detecting the slit disk 60 by the photo sensor 61, and the microprocessor 62 controls the position and movement amount of the main shaft 21 from the output of the photo sensor 61.

Next, the microprocessor 62 uses the platen 2
The operation to detect the inclination of is performed. That is, the microprocessor 62 sends a signal for rotating the D / C motor 20 and monitors the position of the carriage unit 18 in the printing direction by detecting the rotation of the slit disk 23 by the photo sensor 24, and the print head 1 is detected. It is positioned at position 1 shown in FIG.

Next, the microprocessor 62 controls the platen moving section 30 to move the platen 2 and obtain the distance from the platen at the initial position to the ribbon protector bracket 3 at the position 1. That is, U
A forward signal is sent to the / D motor 11 to rotate the platen 2 in the initial position in the ribbon protector bracket 3 direction.

When the forward signal is continuously sent to the U / D motor 11, the platen 2 and the ribbon protector bracket 3 are
The distance between the platen 2 and the ribbon protector bracket 3 finally comes into contact with each other. The contact between the platen 2 and the ribbon protector bracket 3 is detected by the contact detection sensor 17, which stops the rotation of the U / D motor 11.

At this time, the microprocessor 62 uses the feedback pulse from the photosensor 16 to generate U
/ D The motor 11 starts rotating and counts the number of slits detected until the platen 2 contacts the ribbon protector bracket 3.
The distance g1 from the initial position of the platen 2 to the ribbon protector bracket 3 is stored in the platen-ribbon protector bracket distance storage unit 34, and then the U / D motor 11 is rotated in the opposite direction to the above.
Return the platen 2 to the initial position.

Next, the microprocessor 62 controls the carriage moving unit 63 to move the carriage unit 18 in the printing direction, to move the print head 1 from the position 1 to the opposite position 2 and further to the microprocessor. 62 controls the platen moving part 30 to move the platen 2 upward as described above,
The distance g2 from the platen 2 at the initial position to the ribbon protector bracket 3 is obtained and stored in the platen-ribbon protector bracket distance storage unit 34.

The microprocessor 62 determines how much the parallelism between the platen 2 and the carriage unit 21 is deviated from the difference between g1 and g2 stored in the platen-ribbon protector bracket distance storage section 34 as described above. Can be determined. That is, the microprocessor 62 reads g1 and g2 stored in the platen-ribbon protector bracket distance storage unit 34, and obtains the difference between g1 and g2. If there is no difference, it can be determined that the platen 2 and the carriage unit 18 are parallel to each other, and if there is a difference, it can be determined that they are tilted.

When the stepping motor 52 rotates, the cam 56 rotates, and the diameter of the cam 56 changes, so that one end of the main shaft 21 moves up and down.
As a result, the inclination of the main shaft 21 changes, so if there is a difference between g1 and g2, the main shaft 2
1 is moved up and down to obtain g1 = g2, and the number of pulses required to rotate the stepping motor 52 is obtained. The stepping motor 52 is rotated by this number of pulses to finely adjust the inclination of the main shaft 21 to perform stepping. Motor 5
The rotation of No. 2 is stopped to bring it into the holding state.

As a result, the parallelism between the platen 2 and the carriage unit 18 is maintained, and thereafter, the automatic gap setting operation as described in the fourth embodiment is performed to adjust the medium thickness required for printing. To form a gap g. As a result, the gap g required for printing is formed in accordance with the medium thickness and printing becomes possible. At this time, as described above, the main shaft 21 of the main shaft 21 is arranged so that the platen 2 and the print head 1 are parallel to each other. Since the position is adjusted, even if the print head 1 moves for printing, the gap g can be kept constant over the entire area.

Although the slit disk 60 and the photo sensor 61 are mounted on the shaft of the cam 56 in this embodiment, they may be arranged on the shaft of the stepping motor 52.

[0113]

As described above, according to the present invention, the distance between the print head and the platen is measured at a plurality of points on the platen, and the inclination of the platen is calculated from the difference in the distance between the print head and the platen at the plurality of points. Then, while moving the carriage unit in the printing direction along the platen, the platen is moved toward or away from the print head according to this inclination, and the carriage unit moves in the printing direction along the platen. Since a constant gap is formed between the print head and the platen when printing, even if the platen and carriage unit are not parallel to each other due to manufacturing variations, defective assembly, or deformation, it is always possible to print. It can maintain the required constant gap and prevent missing dots and medium jams to provide high quality printing. It has the effect of.

If the parallelism between the platen and the carriage unit is deviated and inclined, the pin stroke of the print head is extended. However, the distance between the print head and the platen is measured at a plurality of points on the platen, and printing is performed at the plurality of points. The platen tilt is calculated from the difference in the distance between the head and the platen, and the carriage unit is moved at the carriage unit moving speed according to this tilt to perform printing, so the carriage unit moves according to the print head pin stroke. It is possible to change the speed and prevent the head pin from breaking due to the improper moving speed of the carriage unit with respect to the pin stroke, eliminating the stoppage of the device due to the breaking of the head pin, and eliminating missing dots. It has an effect that it can be prevented and high quality printing can be provided.

Further, when the distance between the print head and the platen is measured at a plurality of points on the platen and the tilt of the platen is obtained from the difference in the distance between the print head and the platen at the plurality of points, this tilt is determined by the platen itself. If it is determined that there is a foreign substance by judging whether it was obtained by tilting or whether it was obtained by measuring the foreign substance when measuring the distance between the print head and the platen and erroneously obtaining the inclination, Since it is decided to stop the operation and notify the operator, it is possible to prevent erroneous detection due to foreign matter, and by correcting the parallelism between the platen and the print head due to erroneous detection, it is possible to prevent medium jamming and head pin breakage. With
It can provide high-quality printing without missing dots, and can measure the distance between the print head and the platen at multiple points to identify the position of foreign matter, and by notifying the operator of the position of foreign matter, maintenance can be performed. It has an effect that can be easily performed.

Further, according to the present invention, the distance between the print head and the platen is measured at a plurality of points on the platen, the inclination of the platen is obtained from the difference in the distance between the print head and the platen at the plurality of points, and the inclination is determined according to the inclination. By moving the platen side or the carriage unit side so that the print head and platen are parallel, it is possible to maintain a constant gap required for printing at all times, and avoid head pin breaks, dot omissions, and media jams. It has the effect that it can provide high-quality printing by preventing it, and the device side automatically corrects the inclination of the print head and platen, so that maintenance work is not necessary and the accuracy of parts is reduced and assembly is possible. Even if you do not need to perform advanced work, you can always maintain a certain gap necessary for printing, so you can secure high-quality printing,
This has the effect of reducing the cost required to maintain high accuracy.

[Brief description of drawings]

FIG. 1 is a control block diagram of a serial printer showing a first embodiment of the present invention.

FIG. 2 is a side view showing a platen up / down mechanism mounted on a serial printer.

FIG. 3 is a perspective view showing a main configuration of a serial printer.

FIG. 4 is a front view of the serial printer showing the position of the print head.

FIG. 5 is a control block diagram of a serial printer showing a second embodiment of the present invention.

FIG. 6 is a front view of a serial printer showing the concept of a second embodiment of the present invention.

FIG. 7 is a control block diagram of a serial printer showing a third embodiment of the present invention.

FIG. 8 is a control block diagram of a serial printer showing a fourth embodiment of the present invention.

FIG. 9 is a side view showing a platen up / down mechanism mounted on the serial printer.

FIG. 10 is a control block diagram of a serial printer showing a fifth embodiment of the present invention.

FIG. 11 is a perspective view of a serial printer including a carriage unit height adjusting mechanism.

FIG. 12 is a side view showing a schematic configuration of a serial printer.

FIG. 13 is a schematic front view of a serial printer.

FIG. 14 is a side view of a serial printer in which the height of the platen with respect to the print head can be finely adjusted.

[Explanation of symbols]

30 platen moving part 32 carriage moving part 34 platen-ribbon protector bracket distance storage part 37 microprocessor

Claims (6)

[Claims] 1. A platen arranged to face the print head, gap adjusting means for adjusting a gap formed between the platen and the print head, a carriage unit for mounting the print head, and a platen along the platen. A serial printer including a shaft that extends and guides the movement of the carriage unit and a drive mechanism that moves the carriage unit along the shaft, and a carriage drive unit that moves the carriage unit in the printing direction along the platen. , The distance between the print head and the platen is measured at a plurality of points on the platen, the inclination of the platen is obtained from the difference in the distance between the print head and the platen at the plurality of points, and the carriage drive means is controlled to set the carriage unit to the platen. This tilt while moving in the printing direction along Accordingly, the platen driving means is controlled to move the platen toward or away from the print head, and when the carriage unit moves in the printing direction along the platen, the platen is fixed between the print head and the platen. A serial printer having a control means for forming a gap. 2. The serial printer according to claim 1, wherein a carriage speed storing means for storing a moving speed of the carriage unit according to a tilt of the platen, and a distance between the print head and the platen are measured at a plurality of positions on the platen. , The inclination of the platen is obtained from the difference in the distance between the print head and the platen at the plurality of positions, the moving speed of the carriage unit corresponding to this inclination is read from the carriage speed storage means, and based on the read moving speed of the carriage unit. A serial printer including a control unit that controls the carriage driving unit to change the moving speed of the carriage unit. 3. The serial printer according to claim 1, wherein the gap adjusting means includes platen driving means for adjusting the gap by moving the platen toward and away from the print head. Characteristic serial printer 4. The serial printer according to claim 1, wherein the distance between the print head and the platen is measured at a plurality of points on the platen, and the inclination of the platen is calculated from the difference in the distance between the print head and the platen at the plurality of points. Then, determine whether this inclination was obtained by inclining the platen itself, or whether the inclination was erroneously obtained by measuring a foreign substance when measuring the distance between the print head and the platen. When it is determined that there is a serial printer, the serial printer is provided with a control unit that stops the operation and notifies the operator. 5. A platen arranged to face the print head, platen driving means for adjusting the gap by moving the platen toward and away from the print head, and a carriage unit for mounting the print head. A carriage driving means for moving the carriage unit in a printing direction along the platen, the shaft extending along the platen and guiding the movement of the carriage unit, and a drive mechanism for moving the carriage unit along the shaft. In the serial printer provided with, the platen driving means includes a mechanism for independently moving the left and right sides of the platen, and the distance between the print head and the platen is measured at a plurality of points on the platen, and printing at the plurality of points is performed. The inclination of the platen can be calculated from the difference in the distance between the head and the platen. Because, a serial printer that moves the platen by controlling the platen drive means in response to the inclination, characterized by comprising a control means for collimating the print head and the platen. 6. A platen arranged to face the print head, a platen drive means for moving the platen toward and away from the print head to adjust the gap, and a carriage unit for mounting the print head. A carriage driving means for moving the carriage unit in a printing direction along the platen, the shaft extending along the platen and guiding the movement of the carriage unit, and a drive mechanism for moving the carriage unit along the shaft. In a serial printer including: a carriage height adjusting unit that changes the inclination of a shaft that guides the movement of the carriage unit of the carriage driving unit; and a distance between the print head and the platen is measured at a plurality of positions on the platen. Distance between print head and platen The serial is characterized by including a control means for determining the inclination of the platen from the difference, controlling the carriage height adjusting means according to the inclination to change the inclination of the shaft, and making the print head and the platen parallel to each other. Printer.