JP3590700B2 - Heating element array flatness adjustment mechanism - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to the adjustment Organization for adjusting the planarity of the heat-generating element array used in the thermal printer.
[0002]
[Prior art]
The thermal printer records an image on a recording paper using thermal energy generated by a thermal head. This thermal head has a heating element array in which many heating elements are arranged in a line.
[0003]
For example, in a thermal printer, a thermal recording paper which develops color directly by heating is used. The thermal head generates heat in a state where the heating element array is pressed against the thermosensitive recording paper, and records an image line by line. When recording this one line, each heating element generates thermal energy based on the characteristic curve of the thermosensitive recording paper, gives the thermal energy to the thermosensitive recording paper, and virtually squares pixels on the thermosensitive recording paper. Record the dot within. The density of this dot is determined according to the applied thermal energy.
[0004]
The heat energy transmitted from the heating element to the thermal recording paper depends on the contact pressure between the heating element and the thermal recording paper. The higher the contact pressure, the higher the density, and the lower the contact pressure, the lower the density. Therefore, it is necessary to ensure high-precision planarity in the longitudinal direction of the heating element array and to make the heating elements contact the thermal recording paper with a uniform contact pressure.
[0005]
Conventionally, a measuring device shown in FIG. 9 is used to measure the flatness of the heating element array, and an adjusting mechanism for correcting the curvature of the heating element to obtain flatness is provided in the thermal head. In FIG. 9, the thermal head 50 includes a head main body 51 and a support frame 52.
[0006]
As shown in FIG. 10, the head main body 51 includes a ceramic substrate 54 having a heating element array 53 formed on the lower surface, and an aluminum substrate 55 having the ceramic substrate 54 mounted on the lower surface. A plurality of radiating fins 56 are formed at a constant pitch on the upper portion of the aluminum substrate 55 to radiate heat of the aluminum substrate 55.
[0007]
An adjustment reference plate 57 is overlaid on the upper part of each heat radiation fin 56. The adjustment reference plate 57 is, for example, a plate member made of metal, having high rigidity, and having little thermal deformation. As shown in FIG. 9, both ends in the longitudinal direction of the adjustment reference plate 57 are fixed to the radiation fins 56 by two fixing screws 58. A plurality of, for example, three female screws 59 are provided at equal intervals between the fixed both ends.
[0008]
The adjustment screw 61 is screwed into the female screw 59 on the left end of the adjustment reference plate 57, and the tip thereof contacts the upper surface of the heat radiation fin 56 as shown in FIG. 11. Similarly, the adjusting screws 62 and 63 are screwed into the female screws 59 at the center and right end, respectively, and come into contact with the upper surface of the radiation fin 56 at the corresponding position.
[0009]
Each of the adjustment screws 61 to 63 is turned in a direction (hereinafter, referred to as an extrusion direction) that protrudes from the adjustment reference plate 57 toward the heat radiation fin 56, so that the tip end of the adjustment screw faces the upper surface of the heat radiation fin 56. (To the heating element array side). The pressed ceramic substrate 54 below the radiation fin 56 is deformed so as to protrude downward via the aluminum substrate 55. Further, when the adjustment screw is turned in a direction of being pulled out to the rear side of the adjustment reference plate 57 (hereinafter referred to as a pull-back direction) from a state in which the ceramic substrate 54 is deformed so as to protrude by the adjustment screw, the ceramic protruded downward. The substrate 54 is pulled back to the rear side by the elasticity of the head main body 51. Thus, by rotating each of the three adjustment screws 61 to 63 in the pushing direction or the pulling-back direction, the deformation of the heating element array 53 formed on the ceramic substrate 54 in the longitudinal direction is corrected.
[0010]
When correcting the deformation of the heating element array 53, the thermal head 50 is mounted on the measuring device 65. The measurement device 65 includes a support block 66 on which the support frame 52 is set, and, for example, three first to third dial gauges 67 to 69. Each of the dial gauges 67 to 69 is disposed such that the probes 67 a to 69 a are in contact with the portions directly below the adjusting screws 61 to 63 in the portion of the ceramic substrate 54 close to the heating element array 53. Each of these dial gauges 67 to 69 measures the height of the ceramic substrate 54 from an appropriately determined reference horizontal level. Thereby, the deformation of the heating element array 53 can be known indirectly.
[0011]
When the adjustment is performed by the measuring device 65, first, the adjusting screws 61, 63 at both ends are turned so that the numerical values of the first and third dial gauges 67, 69 at both ends are the same. Next, the numerical value of the central second dial gauge 68 is read, and the central part of the ceramic substrate 54 is adjusted by a predetermined formula based on the read numerical value and the numerical values of the first and third dial gauges 67 and 69. Find the position (projection amount). Then, while reading the second dial gauge 68, the adjustment screw 62 is turned to adjust so as to match the obtained adjustment position. Thereafter, the numerical values of the first and third dial gauges 67 and 69 are read, and the adjusting screws 61 and 63 are adjusted again so that they match. After this adjustment, the numerical value of the second dial gauge 68 is read again.
[0012]
If the numerical value of the second dial gauge 68 has reached a predetermined value, the adjustment is completed. If the numerical value has not reached the predetermined value, the center of the ceramic substrate 51 is adjusted with the adjusting screw 62. After adjusting the screws 61 and 63, the second dial gauge 68 is read. By repeatedly performing such adjustment, the shape of the ceramic substrate 54 is adjusted such that the protrusion amount at the center portion is in a range of, for example, 50 to 70 μm with respect to both end portions. By correcting the deformation of the ceramic substrate 54, the flatness of the heating element array 53 is improved.
[0013]
[Problems to be solved by the invention]
By the way, during recording with the thermal head, the head body (heating element array) is adjusted by the bimetal effect generated between the ceramic substrate and the aluminum substrate and between the radiation fins and the aluminum substrate due to the heat generation of the heating element array. To be deformed by being curved away from or closer to the adjustment reference plate. However, in the above-described flatness adjusting mechanism, when the head body is going to be deformed so as to approach the adjusting reference plate, the adjusting screw presses the radiation fin, so that the vertical direction of the heating element array is reduced. Deformation can be suppressed, but when the head body is going to deform away from the adjustment reference plate, each adjustment screw only holds down the radiating fins. The shape changes and the flatness deteriorates. Therefore, during recording of an image, there has been a problem that the shape of the heating element array changes, the contact pressure becomes non-uniform, and density unevenness occurs.
[0014]
SUMMARY OF THE INVENTION The present invention has been made to solve the above problem, and has as its object to provide a flatness adjusting mechanism of a heating element array which is not easily deformed even under the influence of heat during recording.
[0015]
[Means for Solving the Problems]
In order to achieve the above object, in the flatness adjusting mechanism for a heating element array according to claim 1, a first direction in which the heating element array extends above an aluminum substrate on which a substrate having the heating element array is fixed to a lower surface. A first female screw formed in a state extending in the vertical direction from the upper surface of the radiating fins, all or a predetermined number of the radiating fins arranged in a plurality,
A reference plate superimposed on the upper surface of the radiation fin,
A second female screw having a larger diameter than the first female screw and formed in the reference plate so as to face the first female screw;
An outer adjustment screw that is screwed into the second female screw and whose tip presses the upper surface of the radiation fin downward;
A hole formed to penetrate the center of the outer adjustment screw,
An inner adjustment screw which is screwed into the first female screw through the hole, pulls up the radiation fin toward the reference plate, and keeps the upper surface of the radiation fin from separating from the tip of the outer adjustment screw. is there.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
In FIG. 2 showing a thermal head provided with the flatness adjusting mechanism of the present invention, a thermal head 10 includes a head main body 11 and a support frame 12. The head body 11 has the same configuration as the head body 51 shown in FIG. 9, and the ceramic substrate 14 on which the heating element array 13 is formed is fixed to the lower surface of the aluminum substrate 15.
[0017]
A plurality of heat radiation fins 16 are formed on the aluminum substrate 15 at a constant pitch in a direction in which the heating element array 13 extends. Female screws 17 are provided on each of the radiating fins 16 at both ends and a central portion thereof, and on upper surfaces 16a of some of the radiating fins 16 therebetween. The intervals between the female screws 17 are equal in the direction in which the heating element array 13 extends.
[0018]
An elongated adjustment reference plate 20 is disposed on the upper surface 16a of each heat radiation fin 16. The adjustment reference plate 20 is made of a material that is less thermally deformed and has high rigidity. A female screw 21 having a diameter larger than that of the female screw 17 is provided in a portion of the adjustment reference plate 20 that faces each of the female screws 17 of the radiation fin 16. Each female screw 21 is screwed with an outer adjustment screw 22. Each outer adjustment screw 22 has a thread formed on the outer peripheral surface thereof, and a through hole 22a (see FIG. 1) formed at the center. The inside adjustment screw 23 is inserted into the through hole 22a. The head of the inner adjustment screw 23 is larger than the diameter of the through hole 22a, and comes into contact with the receiving surface 22b (see FIG. 1) in the head of the outer adjustment screw. The inner adjustment screw 23 is formed with a male screw. The outer adjusting screw 22, the inner adjusting screw 23, the adjusting board 20, and the female screws 17 of the radiation fins 16 constitute a flatness adjusting mechanism of the heating element array 13.
[0019]
As shown in FIG. 1, each outer adjustment screw 22 screwed to the female screw 21 of the adjustment reference plate 20 has its tip abutting on the upper surface 16 a of the radiating fin 16 to press the radiating fin 16 downward. . On the other hand, the inner adjustment screw 23 is screwed into the female screw 17 of the radiating fin 16 while passing through the through hole 22a of the outer adjusting screw 22, and the radiating fin 16 is pulled up so that the upper surface 16a becomes the tip of the outer adjusting screw 22. Stay away from In this manner, by applying the force for pushing the heat radiation fin 16 downward by the outer adjustment screw 22 and the force for pulling the heat radiation fin 16 upward by the inner adjustment screw 23, the heating element array 13 can be moved to either the upper or lower side. It does not deform in the direction.
[0020]
FIGS. 3 and 4 show a measuring device for measuring the flatness of the heating element array 13. The measuring device includes a measuring table 30, a stroke conversion unit 31 and a computer 32. The measurement table 30 is provided with four support blocks 34, and the thermal head 10 is set horizontally on the measurement table 30 by mounting the support frame 12 on each of the support blocks 34. In addition, although each support block 34 is provided with a clamp or the like for fixing the support frame 12, this is omitted in FIG.
[0021]
Further, a plurality of, for example, seven linear gauges 35 are provided on the measuring table 30. These linear gauges 35 indirectly measure the flatness of the heating element array 13 by measuring the height of the lower surface of the ceramic substrate 14. Each linear gauge 35 has a slidable probe 36 urged upward, and the stroke (slide) of the probe 36 causes the height of the ceramic substrate 14 with respect to a reference horizontal level appropriately determined. Measure.
[0022]
As shown in FIG. 5, each of the linear gauges 35 is arranged such that the probe 36 is in contact with a portion (measurement position) of the ceramic substrate 14 substantially immediately below each outer adjustment screw 22 at a position close to the heating element array 13. Have been. The probe 36 slides up and down according to the height of the measurement position. Each linear gauge 35 generates a stroke signal having a signal level corresponding to the stroke amount of the probe 36. Note that a linear gauge that generates a number of pulses according to the stroke amount of the probe 36 may be used.
[0023]
A stroke signal from each linear gauge 35 is sent to a stroke conversion unit device 31. The stroke conversion unit 31 converts each stroke signal into stroke data representing the stroke amount of each probe 36 according to the signal level. At the time of this conversion, the stroke conversion unit 31 corrects the individual difference of the linear gauge 35, the deviation of the height of the probe 36 in the initial state, and the like, and creates stroke data representing the stroke amount with respect to the reference horizontal level. Each of the obtained stroke data is sent to the computer 32.
[0024]
The computer 32 displays, on the built-in monitor 37, a shape line 40 (see FIG. 8) representing the flatness of the ceramic substrate 14, that is, the flatness of the heating element array 13, based on the input stroke data. As shown in the functional block diagram of FIG. 6, each stroke data from the stroke conversion unit 31 is input to the shape calculating means 32a. The shape calculating means 32a calculates a curve representing the height relative to the reference horizontal level by interpolating between the measurement positions from the seven stroke data. Display data representing this curve is sent to the monitor 37 via the driver 32b. The display on the monitor 37 is updated as needed, and the shape of the heating element array 13 being adjusted is displayed in real time. Thus, the shape of the heating element array 13 can be adjusted while observing the display on the monitor 37.
[0025]
Next, the operation of the above configuration will be described with reference to FIG. The thermal head 10 is placed on the measuring table 30 with the flatness adjustment mechanism attached. The probe 36 of each linear gauge 35 contacts the lower surface of the ceramic substrate 14 and slides downward according to the position. Thus, each linear gauge 35 generates a stroke signal having a signal level corresponding to the stroke amount when the probe 36 is depressed.
[0026]
The stroke signal output from each linear gauge 35 is sent to the stroke conversion unit 31 and is converted into stroke data representing the height of the measurement position of the ceramic substrate 14 with respect to the reference horizontal level. Each of these stroke data is sent to the computer 32. The computer 32 calculates and calculates a shape line representing the planarity of the ceramic substrate 14 (the heating element array 13) based on the input stroke data, and displays the shape line on the monitor 37.
[0027]
FIG. 8 shows an example of a display on the monitor 37. For example, when the right end is higher than the left end of the heating element array 13, as shown in FIG. 8A, the right end of the shape line 40 indicating the planarity of the heating element array 13 is shifted upward from the left end. It is displayed in the shape of Here, the right-side outer adjustment screw 22 in FIG. 2 is rotated in the pushing direction, and the left-side outer adjustment screw 22 is rotated in the pull-out direction. When the right outer adjustment screw 22 is rotated in the pushing direction, the tip of the outer adjustment screw 22 presses the right end radiation fin 16 downward, so that the heating element array 13 projects downward together with the ceramic substrate 14. It is transformed as follows. At this time, the probe 36 that is in contact with the measurement position at the right end of the ceramic substrate 14 is slid downward, and the signal level of the stroke signal increases accordingly, so that the right end of the shape line 40 on the monitor 37 moves downward. .
[0028]
In addition, when the outer adjustment screw 22 at the left end is rotated in the pulling-out direction, the tip moves upward, so that the radiation fin 16 that has been pushed down is displaced upward. Thereby, the heating element array 13 is deformed upward together with the ceramic substrate 14. At this time, the probe 36 which is in contact with the right end portion of the ceramic substrate slides upward by the urging force of the linear gauge 35, so that the signal level of the stroke signal decreases accordingly, and the left end of the shape line 40 on the monitor 37 becomes Move up.
[0029]
For example, as shown in FIG. 8A, horizontal auxiliary lines 41a and 41b extending from the left and right ends of the shape line 40 toward the center are displayed, respectively, so as shown in FIG. 8B. The operator adjusts the height of both ends of the heating element array 13 by rotating the left and right outer adjustment screws 22 so that the heights of the horizontal auxiliary lines 41a and 41b match.
[0030]
Since the monitor 37 displays a shape auxiliary curve 42 representing a predetermined shape of the heating element array 13, the outer adjustment screw 22 is pushed out in the pushing direction so that the shape auxiliary curve 42 matches the shape line 40. And rotation in the pull-out direction to make adjustments. After this adjustment, the inside adjustment screw 23 is screwed into each outside adjustment screw 22 so that the tip of the outside adjustment screw 22 is pressed against the upper surface 16 a of the heat radiation fin 16.
[0031]
If the type of the shape auxiliary curve displayed on the monitor 37 is switched by operating the keyboard 38 (see FIG. 4), the heating element array 13 can be easily adjusted to various shapes.
[0032]
The thermal head 10 in which the flatness of the heating element array 13 has been adjusted as described above is removed from the measuring table 30 and incorporated into a thermal printer. Each heating element of the thermal head 10 generates heat during printing. At this time, due to the bimetal effect of the head main body 11, the heating element array 13 is deformed in the vertical direction of the head main body 10 and tends to be curved. However, since the head body 11 is provided with a force for pushing the radiation fin 16a downward by the outer adjustment screw 22 and a force for pulling the radiation fin 16a upward by the inner adjustment screw 23, deformation due to heat is prevented. Is done. Therefore, even during recording, the flatness of the heating element array 13 is maintained in the same state as at the time of adjustment, the contact pressure of each part of the heating element array 13 with the thermal recording paper becomes uniform, and the occurrence of density unevenness is prevented.
[0033]
In the above embodiment, the number of the outer adjustment screws is smaller than the number of the radiation fins, but the outer adjustment screws may be provided corresponding to all the radiation fins. Further, in order to increase the adjustment accuracy, the number of linear gauges may be larger than the number of outer adjustment screws.
[0034]
Further, in the above embodiment, the height of the ceramic substrate is measured, but the probe may be brought into contact with the heating element array to measure the heating element array. Alternatively, the probe may be brought into contact with the aluminum substrate to measure the planarity of the heating element array indirectly.
[0035]
【The invention's effect】
As described above, according to the present invention, the lower end of the outer adjustment screw applies a pressing force to the radiation fin, and the inner adjustment screw passed through the hole of the outer adjustment screw pulls the radiation fin toward the reference plate. , The verticality of the heating element array in the vertical direction can be adjusted via the radiation fins by the two adjusting screws, and the deformation of the heating element array in the vertical direction due to heat generation during printing can be prevented. be able to.
[Brief description of the drawings]
FIG. 1 is a sectional view of a main part showing an adjustment mechanism embodying the present invention.
FIG. 2 is a perspective view schematically showing a thermal head.
FIG. 3 is a perspective view showing a measuring table of the measuring device.
FIG. 4 is a perspective view showing a stroke conversion unit and a computer of the measuring device.
FIG. 5 is an explanatory diagram showing a contact state between a linear gauge and a head main body.
FIG. 6 is a functional block diagram of the measuring device.
FIG. 7 is a flowchart showing a procedure for adjusting the flatness of the heating element array.
FIG. 8 is an explanatory diagram showing a display example of a monitor.
FIG. 9 is a perspective view showing a conventional measuring device.
FIG. 10 is a perspective view showing a structure of a head main body.
FIG. 11 is a perspective view showing a conventional adjusting mechanism.
[Explanation of symbols]
REFERENCE SIGNS LIST 10 thermal head 11 head body 13 heating element array 14 ceramic substrate 16 radiating fin 16a upper surface 17, 21 female screw 20 adjustment reference plate 22 outer adjustment screw 23 inner adjustment screw 30 measuring table 31 stroke conversion unit 32 computer 35 linear gauge 36 probe 37 monitors

Claims (1)

A thermal head comprising: a substrate having a heating element array extending in a first direction; and an aluminum substrate on which the substrate is fixed on a lower surface and a plurality of radiating fins are arranged in an upper part in a first direction.
A first female screw formed in a state extending in the vertical direction from the upper surface of the radiating fins, all or every predetermined number of the radiating fins,
A reference plate superimposed on the upper surface of the radiation fin,
A second female screw having a larger diameter than the first female screw and formed on the reference plate so as to face the second female screw;
An outer adjusting screw that is screwed into the second female screw and whose tip presses the upper surface of the radiating fin downward;
A hole formed to penetrate the center of the outer adjustment screw,
An inner adjustment screw that is screwed into the first female screw through the hole, pulls up the radiation fin toward the reference plate, and keeps the upper surface of the radiation fin from separating from the tip of the outer adjustment screw. A feature is a flatness adjustment mechanism for the heating element array.

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