JP2979512B2 - Head gap adjustment method and head gap adjustment control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head gap adjustment method and a head gap adjustment control device, and more particularly, to a head gap between a print head and a platen which has an appropriate distance according to the thickness of a medium on which printing is performed. And a head gap adjustment control device.

[0002]

2. Description of the Related Art FIG. 10 is a schematic structural view of a main part of an example of a printer. In this printer, a print head 1 and a platen 2 are provided to face each other, and the print head 1 is pushed out to a platen 2 side from a cutout (not shown) of a ribbon protector 3, and an ink ribbon (not shown) is pressed against a medium 4 to perform printing. I have to.

At the time of printing, an automatic gap adjustment is generally performed in order to set an appropriate head gap according to the thickness of the medium 4. A conventional example of a head gap adjustment method using this automatic gap adjustment will be described. The print head 1 and the ribbon protector 3 are mounted on a carriage 5. The carriage 5 is connected to an eccentric cam 7 via a link 6. The eccentric cam 7 is connected to a gap motor 9 via a belt 8. The gap motor 9 is a pulse motor, and α1-α2 step by step in accordance with a pulse signal.
It turns in the direction.

When the gap motor 9 rotates in the α1-α2 direction, the rotation energy is transmitted to the eccentric cam 7 via the belt 8. The rotation energy of the eccentric cam 7 is converted into the movement energy of the carriage 5 in the β1-β2 direction (gap direction). Further, since the carriage 5 is urged in the β2 direction by the spring 10, the carriage 5 moves in the β2 direction at the short diameter portion of the eccentric cam 7 and moves in the β1 direction at the long diameter portion.

In the mechanism that operates as described above, the procedure for adjusting the head gap according to the thickness of the medium 4 is as follows. First, the print head 1 is pressed against the medium 4 by rotating the carriage 5 in the β1 direction by rotating the gap motor 9 in the α1 direction. Then, the rotation of the gap motor 9 is hindered by the drag, so that the gap motor 9 steps out. Then, after the gap motor 9 is stopped, the gap motor 9 is rotated in the reverse direction. This reverse rotation is rotation for the number of pulses set in advance. This number of pulses is
There is a difference depending on the printer model, etc., and the value differs depending on the design.

The movement of the carriage 5 includes a movement in the space direction called a spacing operation in addition to the movement in the gap direction described above. This space direction refers to the front and back direction in the figure, in other words, the width direction of the medium 4. The spacing operation is performed by driving the space motor 11 to engage with a base frame (not shown) via the space rack 12 and move.

[0007]

However, in the above-described conventional head gap adjusting method, the torque of the gap motor is reduced when the stepping motor is out of synchronization. State. For this reason, even if the number of reverse rotations is equal to the set number of pulses, the actual interval differs from the set interval due to the instability of the pressure, and the set interval cannot be accurately set. There is. As a result, clear characters and images cannot be obtained, resulting in poor print quality.

[0008]

According to a first aspect of the present invention, a head gap adjusting method includes the steps of: operating a gap direction drive unit and a space direction drive unit during a head gap adjustment operation; and attaching a ribbon protector to a medium on a platen. Abut against the frictional force caused by the abutment, and in this spacing, the current value supplied to the space direction drive unit is increased so that the spacing speed before and after the abutment is constant. , And when the current value becomes equal to or greater than a preset reference value, the gap direction driving unit is reversed to extend the timing to a predetermined interval.

In the second head gap adjusting method, at the time of the head gap adjusting operation, the gap direction driving unit and the space direction driving unit are operated to bring the ribbon protector into contact with the medium on the platen, and the frictional force generated thereby. By controlling the current value supplied to the space direction drive unit to be constant at the time of this spacing, the spacing speed after the contact is reduced, and the spacing speed at this time is set in advance. The timing is designed so that the gap direction driving unit is reversed when the value becomes equal to or less than the set reference value and is extended to a predetermined interval.

[0010] A head gap adjustment control device for realizing the first and second head gap adjustment methods is provided.

[0011]

According to the above head gap adjusting method, when the gap motor is driven with a stable force without step-out, the spacing operation is performed, and the change value changed by the frictional force between the ribbon protector and the medium. (The current value or the spacing speed) is detected, the change value is compared with a reference value corresponding to the frictional force, and a timing for adjusting to a predetermined head gap is set according to a result of the comparison. Therefore, the head gap can be accurately adjusted.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. The configuration of the printer is the same as that of the conventional printer, and the same reference numerals are given and the description is omitted. However, the embodiment of the present invention is not limited to this. First, the operation of the main mechanism at the time of head gap adjustment in each of the following embodiments will be briefly described with reference to FIG.

In the first, second and third embodiments of the present invention, the gap motor 9 is used during the head gap adjusting operation.
And the space motor 11 are operated. And
Spacing is performed against the frictional force generated between the ribbon protector 3 and the medium 4. At this time, in Examples 1 and 2,
The space motor 11 is controlled so that the spacing speed becomes constant. In the third embodiment, the space motor 11 is controlled with a constant spacing force so that the spacing speed is reduced by the friction force.

Embodiment 1 FIG. 1 is an explanatory block diagram of a head gap adjustment control system of a printer. Reference numeral 13 denotes a CPU for controlling head gap adjustment and the like. Note that a μCPU is preferable. A ROM 14 stores a program for the CPU 13 to perform a head gap adjustment.

Reference numeral 15 denotes an I / O port.
3 for exchanging signals with each of the mechanical systems described later, and performs A / D conversion and D / A conversion of the signals. A speed detector 16 is mounted on the carriage 5 together with the print head 1 and the space motor 11, and detects a driving speed of the carriage 5 in the space direction.
For example, an optical sensor and a disk slit are used.

Reference numeral 17 denotes a driver, which is a space motor 11
Is to be driven. Reference numeral 18 denotes a current value detector for detecting a current value applied to the space motor 11. 1
A driver 9 drives the gap motor 9. FIG. 2 is a conceptual block diagram of a head gap adjustment control device in which the head gap adjustment control system having the above configuration is represented by function realizing means.

The head gap adjustment control device 20 includes:
In the CPU 13 and the ROM 14, the head gap control may be performed according to a program stored in the ROM 14, or each function realizing unit described below may be configured by a circuit or the like. Reference numeral 21 is a reference value storage means for storing a reference value of an upper limit of a current value supplied to the space motor 11 for spacing the carriage 5 at a constant speed. The setting of the reference value
The following conditions were satisfied.

At the time of head gap adjustment, the ribbon protector 3 and the ribbon protector 3 are adjusted according to the pressure applied to the medium 4, the spacing speed, the state of the surface of the medium 4, the thickness of the medium 4, and the like. The frictional force generated with the medium 4 changes. To space the carriage 5 at a constant speed against this frictional force, the space motor 1
The current value supplied to 1 must be gradually increased.

In this case, the reference value is large enough to be distinguished from the current value when there is no frictional force where the ribbon protector 3 and the medium 4 are not in contact with each other, and the gap motor 9 is not out of step. It is set by examining in advance by an experiment or the like on condition that the current value is used. Reference numeral 22 denotes a current value comparing unit which compares a current value sent from the current value detector 18 with a reference value sent from the reference value storage unit 21 and, when the current value becomes equal to or larger than the reference value, the gap motor 9. And a stop control signal for the space motor 11.

Reference numeral 23 denotes a space direction speed control means for controlling a current value supplied to the space motor 11 so as to space the carriage 5 at a constant speed, and receives a stop control signal of the space motor 11. The space motor 11 is stopped. Reference numeral 24 denotes a gap direction speed control means for controlling a current value supplied to the gap motor 9 so as to move the carriage 5 in the gap direction. The motor 9 is stopped.

Next, referring to the flowchart of FIG.
The head gap adjustment control in the case of the printer in FIG. 10 will be described. FIG. 4 shows the head gap and the space motor 11.
4 is a graph for explaining a change over time of a supply current to the power supply. In the following description, it is assumed that the processing is performed by the CPU 13 by each function realizing unit shown in FIG. However, it is assumed that the current value detector 18 is outside the CPU 13 as shown in FIG. S1: When the medium 4 is set on the platen 2, the CPU 13 starts up the space motor 11 and issues a command to supply a large current I to the space motor 11 until the time t1 for stable driving as shown in FIG. , Processing is S2
Transfer to S2: As shown in FIG.
A constant current smaller than the reference value A is supplied to the space motor 11 so that the space motor 11 is driven stably and the carriage 5 is operated at a constant speed. S3: The CPU 13 rotates the gap motor 9 to narrow the head gap X from the retracted position. The beginning of the narrowing is shown at time t2 in FIG. When the head gap X is reduced, the ribbon protector 3 comes into contact with the medium 4 (in FIG. 4, it is assumed that the ribbon protector 3 has come into contact immediately). Then, the pressure applied by the ribbon protector 3 to the medium 4 gradually increases, and the frictional force between the ribbon protector 3 and the medium 4 due to the spacing operation increases. CPU 13
Is to feed back the speed detected by the speed detector 16 to increase the supply current I to the space motor 11, and to perform the spacing operation at a constant speed against the frictional force. S4: The CPU 13 determines the supply current I of the space motor 11
Is larger than or equal to the reference value A. If I <A, the process returns to S3. If I ≧ A, the process proceeds to S5. If I = A, the process may return to S3. S5: The CPU 13 stops the gap motor 9. S6: The CPU 13 stops the space motor 11. S7: The CPU 13 reversely rotates the gap motor 9 by the preset number of pulses according to the reference value A,
At time t4, a predetermined head gap X corresponding to the setting of the printer is controlled.

As described above, if the timing of the reverse rotation of the gap motor 9 is set to a predetermined head gap X, the head gap can be accurately adjusted regardless of the thickness of the medium 4. . As shown in FIG. 4, the current value I may change as shown by a dotted line. That is, this is a case where the current value I is increased when spacing is performed against a load force due to the roughness of the medium 4 or the adhesion of dust. It is preferable that the reference value A is set to a size that does not cause the gap motor 9 to be reversed, in consideration of experiments and the like in advance when spacing against the load force.

Embodiment 2 FIG. 5 is an explanatory block diagram of a head gap adjustment control system of the printer. This head gap adjustment control system is different from the first embodiment in that the current value detector 18 described in the first embodiment is included in the CPU 13. Then, instead of detecting the current value I supplied to the space motor 11, a correction current value of the current value I supplied to the space motor 11 is detected. Further, the reference value is also a small value corresponding to the correction current value.

Therefore, even if the current value I supplied to the space motor 11 is large, the head gap can be accurately adjusted without imposing a load on the CPU 13 and regardless of the thickness of the medium 4. become able to. Other processes and operations are the same as those in the first embodiment, and a description thereof will not be repeated. Embodiment 3 FIG. 6 is an explanatory block diagram of a head gap adjustment control system of the printer.

This head gap adjustment control system does not include the current value detector 18 described in the first and second embodiments. Other configurations are the same as those in the first embodiment, and a description thereof will be omitted. FIG. 7 is a conceptual block diagram of a head gap adjustment control device in which the head gap adjustment control system having the above configuration is represented by function realizing means.

This head gap adjustment control device 25 includes:
In the CPU 13 and the ROM 14, the head gap control may be performed according to a program stored in the ROM 14, or each function realizing unit described below may be configured by a circuit or the like. Reference numeral 26 denotes a reference value storage means for storing a reference value of a lower limit of the speed at which the carriage 5 moves in the space direction when a constant current is supplied to the space motor 11. The reference value was set so as to satisfy the following conditions.

At the time of adjusting the head gap, the ribbon protector 3 and the ribbon protector 3 are adjusted according to the pressure applied to the medium 4, the spacing speed, the state of the surface of the medium 4, the thickness of the medium 4, and the like. The frictional force generated with the medium 4 changes. When the carriage 5 supplies a constant current to the space motor 11 against the frictional force, the spacing speed of the carriage 5 decreases.

In this case, the reference value is large enough to be distinguished from the current value when there is no frictional force where the ribbon protector 3 and the medium 4 are not in contact with each other, and the gap motor 9 is not out of step. It is set by examining in advance by experiments or the like on condition that the speed is set. 27 is a speed comparing means which compares the speed sent from the speed detector 16 with the reference value sent from the reference value storage means 26, and when the speed becomes lower than the reference value, the gap motor 9 and the space motor 11 Is issued.

Reference numeral 23 denotes a space direction speed control means for controlling the space motor 11 with a constant current so as to space the carriage 5 and receives a stop control signal of the space motor 11. At this time, the space motor 11 is stopped. Reference numeral 24 denotes a gap direction speed control means for controlling a current value supplied to the gap motor 9 so as to move the carriage 5 in the gap direction. The motor 9 is stopped.

Next, referring to the flowchart of FIG.
The head gap adjustment control in the case of the printer in FIG. 10 will be described. FIG. 9 shows the head gap and the space motor 11.
4 is a graph for explaining a change over time of a supply current to the power supply. In the following description, it is assumed that each function realizing means shown in FIG. However, it is assumed that the speed detector 16 is outside the CPU 13 as shown in FIG. S1: When the medium 4 is set on the platen 2, the CPU 13 starts up the space motor 11 and issues a command to supply a large current I to the space motor 11 until a stable driving time t1 as shown in FIG. , Processing is S2
Transfer to S2: As shown in FIG. 9, the CPU 13 supplies a constant current to the space motor 11 after time t1 to drive the space motor 11 stably, and operates the carriage 5 at a constant spacing speed. S3: The CPU 13 rotates the gap motor 9 to narrow the head gap X from the retracted position, and the ribbon protector 3
And the medium 4. The time of this contact is time t2 in FIG. Then, the pressure applied by the ribbon protector 3 to the medium 4 gradually increases, and the frictional force between the ribbon protector 3 and the medium 4 due to the spacing operation increases. While monitoring the speed detected by the speed detector 16, the CPU 13 supplies a constant current to the space motor 11 to perform the spacing operation. S4: The CPU 13 checks whether or not the speed V of the carriage 5 has become smaller than the reference value B. If V> B, the process returns to S3. If V ≦ B, the process returns to S3.
Transfer to 5. If V = B, the process may return to S3. S5: The CPU 13 stops the gap motor 9. S6: The CPU 13 stops the space motor 11. S7: The CPU 13 reversely rotates the gap motor 9 by the number of pulses set in advance according to the reference value B.
At time t4, a predetermined head gap X corresponding to the setting of the printer is controlled.

As described above, when the predetermined head gap X is set, the head gap can be accurately adjusted regardless of the thickness of the medium 4. Also,
In the third embodiment, since the detection is performed only by the speed detector 16, the components of the head gap adjustment control device are different from those of the first embodiment.
There is an effect that less is required as compared with.

[0032]

As described above, according to the head gap adjustment method and the head gap adjustment control device of the present invention, when the gap motor is driven with a stable force without stepping out, the spacing operation is performed. A change value (current value or spacing speed) that changes due to a frictional force between the ribbon protector and the medium is detected, and the change value is compared with a corresponding reference value corresponding to the frictional force. In order to adjust the head gap to a predetermined head gap in accordance with the timing.

For this reason, since the change value is obtained when the gap motor is driven stably, if the same medium is used, there is no variation in the timing of reverse rotation of the gap motor, and a predetermined head gap can be obtained with the same number of pulses. Therefore, an effect that accurate adjustment becomes possible is obtained. As a result, clear characters and images can be obtained, and the print quality can be improved.

[Brief description of the drawings]

FIG. 1 is an explanatory block diagram of a head gap adjustment control system of a printer according to a first embodiment.

FIG. 2 is a conceptual block diagram of a head gap adjustment control device.

FIG. 3 is a flowchart of a process of head gap adjustment control.

FIG. 4 is a graph of a time change of a head gap and a current.

FIG. 5 is an explanatory block diagram of a head gap adjustment control system of the printer according to the second embodiment.

FIG. 6 is an explanatory block diagram of a head gap adjustment control system of a printer according to a third embodiment.

FIG. 7 is a conceptual block diagram of a head gap adjustment control device.

FIG. 8 is a flowchart of a process of head gap adjustment control.

FIG. 9 is a graph showing a temporal change of a head gap and a current.

FIG. 10 is a schematic configuration diagram of a main part of a printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Print head 2 Platen 3 Ribbon protector 4 Medium 5 Carriage 6 Link 7 Eccentric cam 8 Belt 9 Gap motor 10 Spring 11 Space motor 12 Space rack 13 CPU 14 ROM 16 Speed detector 18 Current detector 20, 25 Head gap adjustment control Device 21 Reference value storage means 22 Current value comparison means 23 Space direction speed control means 24 Gap direction speed control means 26 Reference value storage means 27 Speed comparison means

Claims (4)

(57) [Claims] 1. A head gap adjusting method for adjusting an interval between a platen of a ribbon protector provided between a print head and a platen, wherein a gap direction driving unit and a space direction driving unit are operated during a head gap adjusting operation. The ribbon protector is brought into contact with the medium on the platen, and the spacing is performed against the frictional force caused by the ribbon protector.In this spacing, the current value supplied to the space direction drive unit is increased so that the ribbon protector is before and after the contact. And the spacing speed is maintained at a constant speed, and when the current value becomes equal to or higher than a preset reference value, the timing is designed so that the gap direction driving unit is reversed and expanded to a predetermined interval. A head gap adjustment method characterized by the above-mentioned. 2. A head gap adjusting method for adjusting an interval between a platen of a ribbon protector provided between a print head and a platen, wherein a gap direction driving unit and a space direction driving unit are operated during a head gap adjusting operation. The ribbon protector is brought into contact with the medium on the platen, and the spacing is performed against the frictional force generated by the ribbon protector, and the current value supplied to the space direction drive unit during this spacing is controlled to be constant. When the subsequent spacing speed decreases and the spacing speed at this time becomes equal to or less than a preset reference value, the timing is designed so that the gap direction driving unit is reversed and expanded to a predetermined interval. Characteristic head gap adjustment method. 3. A head gap adjusting control device for adjusting a distance between a platen of a ribbon protector provided between a print head and a platen, wherein a current is supplied to a gap direction driving unit so as to move the ribbon protector in the gap direction. And a gap direction speed control means for driving the ribbon protector so that the ribbon protector is brought into contact with the medium on the platen and spaced at a constant speed against a frictional force generated by the contact. The space direction speed control means for changing the value of the current supplied to the space direction drive unit, the current value detection means for detecting the current value supplied to the space direction drive unit, and a preset reference value of the current are stored. Reference value storage means, comparing the current value with the reference value, and when the current value becomes equal to or greater than the reference value, a gap Current value comparing means for outputting a stop signal for stopping the driving of the direction driving section and the space direction driving section, and the speed comparing means outputs a stop signal to drive the gap direction driving section and the space direction driving section. A head gap adjustment control device, wherein the head gap adjustment control device controls to extend the gap direction drive unit to a predetermined interval by stopping the gap direction drive unit by stopping the gap direction drive unit. 4. A head gap adjusting control device for adjusting a distance between a platen of a ribbon protector provided between a print head and a platen, wherein a gap for supplying a current to a gap direction driving unit for moving the ribbon protector in the gap direction. A direction speed control means; and a space direction drive unit that drives the gap direction drive unit to cause the ribbon protector to abut against the medium on the platen and space the frictional force generated by the abutment. A space direction speed control unit that supplies a current of the same, a speed detection unit that detects a spacing speed of the space direction drive unit, a reference value storage unit that stores a preset reference value of the spacing speed, and the spacing speed. Is compared with the reference value, and when the spacing speed falls below the reference value, Speed comparing means for outputting a stop signal for stopping driving of the direction driving section and the space direction driving section, and the speed comparing section outputs a stop signal to stop driving of the gap direction driving section and the space direction driving section. A head gap adjustment control device for controlling the gap direction drive unit to reverse the gap direction drive unit so as to extend the gap direction drive unit to a predetermined interval.