JP4522309B2 - Platen parallelism adjustment device - Google Patents

Description

  The present invention relates to a platen parallelism adjusting device, and more particularly to an apparatus for adjusting the parallelism of a platen with respect to a print head of a printer.

In a printer, in order to make the print quality of a print medium (recording paper) by a print head moved in the print direction uniform over the entire print head movement direction, the platen is placed on the print head over its entire length. Need to be parallel. However, since the mounting state of the guide rod that supports the carriage of the print head and the support state of the platen are not completely horizontal, the inclination of the platen is measured and the parallelism of the platen is adjusted according to the measured inclination. There is a need. Conventionally, various apparatuses for measuring the inclination of a platen and adjusting the parallelism of the platen according to the measured inclination have been disclosed (for example, see Patent Documents 1 to 8).
Japanese Patent Laid-Open No. 03-027960 Japanese Patent Application Laid-Open No. 07-1781979 Japanese Patent Laid-Open No. 08-058165 JP 09-220840 A Japanese Patent Laid-Open No. 10-1000048 Japanese Patent Laid-Open No. 10-264457 JP 2001-030554 A JP 2001-113765 A

  These can be broadly divided into those that measure the tilt before printing and adjust the parallelism (pre-adjustment type), and those that measure the tilt before printing and store the measured values, and move the print head during printing. Some of them adjust the parallelism according to the position (adjustment type during printing).

Among the above prior arts, Patent Documents 1, 5, and 7 describe two platen lifting / lowering means corresponding to both ends of the platen and positions that contact the platen print head (hereinafter referred to as printing) in order to measure the inclination of the platen. Two platen position detecting means for detecting the movement distance from the head contact position to the reference position are used. These are provided with two platen lifting / lowering means and two platen position detecting means, and thus there are problems of an increase in manufacturing cost and difficulty in securing an installation space.

  Among the above prior arts, Patent Documents 2, 3, and 5 measure the inclination before printing and store the measured value, and raise and lower the platen by the platen moving means based on the measured value at the time of printing. Adjust the parallelism. These have the problem that since the platen movement control process must be performed in parallel with the printing process, the software processing load at the time of printing becomes large, which causes a high-speed printing suppression factor.

  Patent Document 4 stores gap measurement values at the measurement positions on the left and right sides of the platen, calculates parallelism based on the two measurement values and the distance between the two measurement positions, and calculates the calculated value as A device that determines whether or not parallelism is appropriate compared with a reference value and displays a gap measurement value or parallelism is disclosed. However, it is easy to determine whether the parallelism is appropriate from the displayed gap measurement value or parallelism, but after that determination, a specific method is disclosed for how to adjust the parallelism in practice. Not.

  The present invention has been made in view of the above points, and the problems to be solved include parallelism that reduces manufacturing costs, facilitates and corrects parallelism adjustment, and prevents an increase in load during printing processing. It is to provide a degree adjusting device. More specifically, in order to measure the inclination, the minimum number of platen lifting / lowering means and platen position detecting means are used, and simple adjustment means are used to reduce the manufacturing cost and adjust the parallelism based on the measured values. In addition, it is possible to prevent the increase in the software processing load during printing by pre-adjustment.

In order to solve the above problems, the present invention provides a print head moving means for moving the print head in the print direction, and a platen extending in parallel with the move direction of the print head. in a printer having a platen elevating means that to ensure a predetermined gap between the print medium supported on the platen, the platen parallelism adjusting device, the platen elevating means, a stepping motor (hereinafter, referred to as S motor. ), A camshaft that is supported at one end so as to be movable up and down, and is provided with the rotational force of the stepping motor via a friction clutch, a plurality of eccentric cams fixed to the camshaft, and the eccentrics provided on the platen thereby composed of a cam follower which is in contact with the cam, rotatably supported by lifting one end of the camshaft Height adjusting means for adjusting the supporting height by rotation of the adjusting screw, detection means (hereinafter referred to as HP sensor) for detecting that the platen has been moved to a home position (hereinafter referred to as HP), and a platen. Means for counting the number of steps given to the S motor to move the print head from the print head contact position to HP, and the platen when the print head is in the left measurement position is moved from the print head contact position to HP The number of steps given to the S motor and the number of steps given to the S motor to move the platen from the print head contact position to HP when the print head is at the right measurement position of the moving range. Calculating means for calculating the difference between them, or calculating means for converting the number of steps of the difference into the rotation angle of the adjusting screw, and the calculation result is displayed. It is characterized by being configured and display means that (claim 1).

  With the above configuration, when the platen elevating means raises the platen, when the platen comes into contact with the print head, the friction clutch works to stop the rise of the platen. The platen lifting / lowering means moves the platen from the print head contact position to HP, that is, a position detected by the HP sensor. The step number counting means counts the number of steps given to the S motor to move the platen from the print head contact position to HP. When measuring the tilt, the print head moving means moves the print head to the left measurement position, and then counts the number of steps Sa given to the S motor to move the platen from the print head contact position to the HP sensor detection position. Subsequently, after the print head is moved to the right measurement position by the print head moving means, the number of steps Sb given to the S motor for moving the platen from the print head contact position to HP is counted. The calculation means obtains the difference (Sa−Sb) between this and the number of steps (Sb) at the right measurement position with reference to the number of steps (Sa) at the left measurement position. That is, the inclination of the platen is measured. The calculation means may further convert the difference into a required rotation angle of the adjustment screw. Although the conversion rate depends on the pitch of the adjusting screw, for example, one step is 12.6 degrees (the platen lifting distance is 0.0175 mm). The display means displays the number of steps as the calculation result or the rotation angle of the adjusting screw converted from the number of steps as a numerical value. Therefore, the maintenance staff can accurately adjust the parallelism by turning the adjusting screw in the positive direction or the negative direction based on the display content. This parallelism adjustment is performed before printing, that is, when printing processing is not performed.

In the present invention, it is desirable that the display means displays the result of the arithmetic means with a positive or negative sign and the number of steps as the adjustment amount or the numerical value of the rotation angle of the adjustment screw (claim 2).
The display means displays the sign of “positive” or “negative” and the value of the difference in close proximity according to the calculation result. Therefore, the maintenance staff can precisely perform the adjustment work by turning the adjusting screw accurately in the positive direction or the negative direction based on the display content.

  The display means is preferably provided in the vicinity of the adjusting screw. In such a case, the maintenance staff can perform the parallelism adjustment work while viewing the display contents close to each other.

Furthermore, in the present invention, it is desirable to use an adjustment screw having a negative engagement groove on the head, and to provide a step number or rotation angle scale around the head of the adjustment screw on the surface that supports the head of the adjustment screw. (Claim 4).
Thereby, the maintenance staff can adjust the parallelism with higher accuracy by turning the adjusting screw while viewing the display content of the display means and matching the engagement groove with the scale corresponding to the display content.

According to the first aspect of the present invention, the platen parallelism adjusting device includes a platen elevating means, an S motor, and a camshaft that is supported at one end so as to be movable up and down, and is provided with a rotational force of the S motor via a friction clutch. The camshaft includes a plurality of eccentric cams fixed to the camshaft and cam followers that are in contact with the eccentric cams provided on the platen, and supports one end of the camshaft constituting the platen elevating means so as to be movable up and down. A height adjusting means for adjusting the supporting height by rotation of the adjusting screw, an HP sensor for detecting that the platen has been moved to the HP, and the platen for moving the platen from the print head contact position to the HP. The means for counting the number of steps given to the S motor and the platen when the print head is in the left measurement position are moved from the print head contact position to H. The number of steps given to the S motor and the number of steps given to the S motor to move the platen when the print head is in the right measurement position from the print head contact position to HP. Comprising computing means for obtaining the difference, computing means for converting the number of steps of the difference into the rotation angle of the adjusting screw, and display means for displaying the computation result, the platen lifting means, the platen position Since only one detection means (HP sensor) is used and the number of components can be reduced, the manufacturing cost can be reduced. Further, since the parallelism adjustment is performed before printing, the parallelism adjustment does not increase the burden of the printing process of the CPU, and thus does not hinder high-speed printing.

  According to the invention of claim 2, the display means displays the result of the calculation means with a positive or negative sign and the number of steps as the adjustment amount or the value of the rotation angle of the adjustment screw. Based on the display content, the adjustment screw can be accurately turned in the positive direction or the negative direction to perform the adjustment work precisely.

  According to the invention of claim 3, since the display means is provided in the vicinity of the adjusting screw, the platen parallelism can be adjusted accurately and quickly while viewing the display content.

  According to the invention of claim 4, since the adjustment screw having the negative engagement groove is used, and the scale of the step number or the rotation angle is provided around the adjustment screw head on the surface supporting the adjustment screw head. The maintenance staff can adjust the parallelism with higher accuracy by turning the adjusting screw and matching the engagement groove with the scale corresponding to the display content while viewing the display content of the display means.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a schematic configuration of a platen parallelism adjusting device according to the present invention, and FIG. 2 is a front view of a main part of the printer, showing a state in which a print head is present at a left measurement position. FIG. 3 is a front view of the main part of the printer, and shows a state in which the print head is present at the right measurement position. 4 is a perspective view of the platen support height adjusting means, FIG. 5 is a perspective view showing an example of an HP sensor for detecting that the platen has reached HP, and FIG. 6 is a plan view showing an example of an adjustment screw mounting position and a display unit. 7 is a detailed view of the display unit, FIG . 8 is an enlarged view of a circle X portion of FIG. 7, FIG. 9 is a flowchart showing the operation in the platen parallelism adjustment mode, and FIG. 10 is a detailed view of the platen parallelism measurement operation. It is a flowchart to show.

  In order to realize the parallelism adjustment of the platen according to the present invention, as shown in FIG. 1, the print head moving means A, the platen lifting / lowering means B, the HP sensor C as the platen position detecting means, and the platen support are schematically shown. It has a CPU (F) including a height adjusting means D, a display means E, a control means 32, a counting means 33 and a calculating means 34, and a storage means G. The storage means G includes a program memory 35 and a data memory 36.

2 and 3 , 1a and 1b are upper frames of the printer, and 2a and 2b are lower frames. Print head moving means A is provided on the upper frames 1a and 1b. For example, the print head moving means A supports the carriage 4 on the upper and lower guide rods 3a and 3b provided between the upper frames 1a and 1b so as to be slidable in the axial direction of the guide rods 3a and 3b. The print head 5 is attached to the carriage 4 , and a part of the timing belt 8 wound around the pulley 6a attached to the upper frame 1a and the pulley 6b provided in the S motor 7 attached to the upper frame 1b is used. The print head 5 is configured to be coupled to the carriage 4 and moved between the pulleys 6a and 6b along the axis of the guide rods 3a and 3b by one-way rotation and reverse rotation of the S motor 7. . A ribbon mask 9 is provided at the lower end of the print head 5.

  Between the lower frames 2a and 2b, the platen 10 is supported by a sliding guide mechanism (not shown) so as to be movable up and down at a certain position in the left and right direction below the movement area of the ribbon mask 9. One platen lifting / lowering means B for moving the platen up and down from the position where the upper surface of the platen abuts against the ribbon mask of the print head (corresponding to the print head contact position) to the lower HP is located below the platen 10. Is provided.

The platen lifting / lowering means B is configured as follows. That is, an S motor 11 is attached to the lower frame 2a, and the camshaft 12 that penetrates the lower frame 2a from the outside and continues to the vicinity of the lower frame 2b is fixed to the lower frame 2c with brackets 13a, The eccentric cams 15 are fixed to two locations that are rotatably supported by bearings 14a and 14b such as ball bearings held by 13b and are spaced from the both ends of the camshaft 12 by a certain distance in the central direction. Then, a friction clutch 16 such as a torque limiter (registered trademark) is interposed at an end portion of the camshaft 12 on the lower frame 2a side, and an end portion of the driving side portion of the camshaft 12 protrudes to the outside of the lower frame 2a. A belt 18 is wound around a pulley 17a fixed to the end of the pulley 17b and a pulley 17b fixed to the tip of a drive shaft protruding outside the lower frame 2a of the S motor 11.

A lower portion of the two locations spaced equidistantly in the central direction from both ends of the platen 10, the positions corresponding to the eccentric cams 15 of the camshaft 12, cam follower 19 is mounted, placed always eccentric cam 15 Has been.

With the above configuration, when the S motor 11 is rotated in a predetermined direction, the platen 10 is raised via the cam follower 19 by a predetermined amount of rotation of the eccentric cam 15 and the upper surface of the platen is the ribbon mask of the print head. 9, the torque limiter 16 acts and the rotational force of the S motor 11 is cut off and is not transmitted to the driven side portion of the camshaft 12, so that the platen 10 is stopped at the print head contact position. When the S motor 11 of the platen lifting / lowering means B is rotated in the reverse direction, the platen 10 is lowered via the eccentric cam 15 that is reversed.

  For the platen 10, one HP sensor C is provided as detection means for detecting that the platen 10 has reached or exists at the HP. In the illustrated example, this HP sensor C is provided with a light shielding plate 20 as a member to be detected at the center position in the longitudinal direction of the platen, and when the lowered platen 10 reaches HP in the lower frame 2c, the light shielding plate A photoelectric switch 21 that outputs a detection signal when light is blocked by 20 is provided. The light shielding plate 20 and the photoelectric switch 21 are merely examples of the configuration, and other known configurations can be used for the HP sensor.

In the present invention, in order to adjust the parallelism of the platen, the adjusting means for adjusting the platen support height at the end (the right end in FIGS. 1 and 2) opposite to the torque limiter 16 of the camshaft 12. D is provided. As shown in FIG. 4 , the adjusting means D is configured as follows. That is, an inverted L-shaped support plate 23 inserted through a hole 22 provided in the lower frame 2c is joined by welding or the like at its upper horizontal portion, and a vertically long hole (not shown) provided in a vertical portion of the support plate 23. One end of the camshaft 12 is inserted into the camshaft 12 so as to be movable up and down. An L-shaped bracket 13b attached to the camshaft 12 via a bearing 14b is used as an adjustment plate, and a vertical extension 24 provided on the bracket 13b is formed in the hole 22. And is extended upward, passes through a set screw 25 through a vertically long hole (not shown) formed in the upper end of the extension 24, and is formed on the upper protrusion 23 a of the support plate 23. The bracket 13b is fixed up and down by tightening in a screw hole (not shown). Reference numeral 26 denotes a holding portion that improves the guideability of the bracket 13b with respect to the support plate 23.

An adjustment screw 27 is penetrated downward at a position near the hole 22 of the frame 2c, and an E-ring or the like is attached to the adjustment screw immediately below the frame 2c so as to be rotatably held at a certain position. And the lower end part of the adjustment screw is screwed into the horizontal part 28 of the bracket 13b. The head 29 of the adjustment screw 27 is provided with a minus (-) engagement groove, and a simple tool, for example, the tip of a minus driver is fitted into the engagement groove and rotated to the right or left. The support height of one end of the camshaft 12 can be adjusted.
By providing play in the attachment of the bearing 14a to the bracket 13a, the support height of one end of the camshaft 12 can be adjusted with the rotation of the adjusting screw 27.

  As shown in FIG. 8, a scale 30 is provided on the support surface of the adjustment screw 27 along a circumference centered on the axis of the adjustment screw. Therefore, when the engagement groove of the head 29 of the adjustment screw 27 is negative, the adjustment screw is turned to a predetermined rotation angle by turning the adjustment screw with a flathead screwdriver and aligning one end of the engagement groove with a predetermined scale. There is an advantage that it can be turned accurately.

As shown in FIG. 6, a display portion E is provided in the vicinity of the adjustment screw 27. As an example, the display unit E includes display elements 31a, 31b, and 31c each composed of a three-digit seven segment as shown in FIG. 7, and the hundredth display element 31a is calculated by a calculation means described later. "+" Or "-" or "1" or "0" is displayed as the positive or negative sign of the result, and the tenth and first display elements 31b and 31c display the numerical value of the operation result. .

When the processing mode of the printer is selected as the platen parallelism adjustment mode at the time of delivery of the printer or before use, for example, the CPU starts executing a program for processing the platen parallelism adjustment mode. As shown in FIG. 9, first, an initial operation (step 1; hereinafter, steps are represented by S) is performed. That is, the control means 32 controls the platen lifting / lowering means B to lower the platen 10 to the position where the HP sensor C is operated, that is, the position where the light shielding plate 20 operates the photoelectric switch 21, and then the control means 32. Controls the print head moving means A to move the print head 5 to the retracted position outside the print area.

  Next, the CPU performs a platen parallelism measurement operation (S2). Details of S2 are as shown in FIG. That is, the control unit 32 controls the print head moving unit A to move the carriage 4 to the left measurement position (S21). Subsequently, a platen inclination measurement operation (S22) is performed. That is, the platen lifting / lowering means B is controlled to rotate the S motor 11 in a predetermined direction for a predetermined time, thereby raising the platen 10. When the upper surface of the platen comes into contact with the ribbon mask 9, the torque limiter 16 acts and the platen is stopped at that position. Next, the S motor 11 is reversely rotated to lower the platen, and at the same time, the counting means 33 starts counting the number of steps given to the S motor 11 to lower the platen. When the platen is lowered to HP, the photoelectric switch 21 is operated by the light shielding plate 20, and a detection signal is input to the CPU. As a result, the HP arrival of the platen is detected, and the number of steps given to the S motor 11 until reaching the HP from the print head contact position (precisely the ribbon mask contact position) of the platen is counted by the counting means 33. The Thus, the distance from the print head contact position of the platen to the HP is measured. When the HP of the platen is detected, the control means 32 controls the platen lifting / lowering means B again to perform the homing operation. The count value Sa in S22 is stored in the data memory 36 as a measurement result at the left measurement position (S23).

  Next, the control means 32 controls the print head moving means A to move the carriage 4 to the right measurement position (S24). Subsequently, the platen inclination measurement operation (S25) is performed at the right measurement position, as in step S22. The count value Sb by the counting means 33 in S25 is stored in the data memory 36 as a measurement result at the right measurement position (S26).

When the measurement result by the platen inclination measurement operation at the right measurement position is stored, the CPU 34 calculates the difference (Sa−) between the measurement result (Sa) at the left measurement position and the measurement result (Sb) at the right measurement position. Sb), that is, one of the two locations spaced apart in the longitudinal direction of the platen, for example, the platen print head in the other location, using the distance from the platen print head contact position to the HP at the left measurement position as a reference value. A difference from the distance from the contact position to the HP, that is, an inclination is obtained (S27). The difference value is the number of steps of the S motor 11 and is stored in the data memory 36 (S28) .

After the measured value of tilt is stored, the CPU again controls the print head moving means A to move the print head 5 to the retracted position (S29), and then returns to the main flow of FIG. The number of steps as the parallelism measurement result is read from the data memory 36 and displayed on the display unit E (S3) . In this case, when the value of the difference (Sa−Sb) is a positive number, that is, when the right side of the platen is higher than the left side, the display element 31a at the left end of the display unit E has “+” or “1”. When the value of the difference (Sa−Sb) is a negative number, that is, when the right side of the platen is lower than the left side, “−” or “ A sign of “0” is displayed. Then, the two display elements 31b and 31c at the right end of the display means display the number of steps as a tilt measurement value.

  Based on the displayed content, the maintenance staff engages the engagement groove of the head 29 of the adjustment screw 27 with an arbitrary tool, for example, the tip of a flat-blade screwdriver, and the sign is “+” or “1”. The adjustment screw 27 is rotated counterclockwise. If the sign is “−” or “0”, the adjustment screw 27 is rotated clockwise. In this case, the rotation angle is determined while looking at an existing platen parallelism adjustment conversion table in which the number of steps is converted into the rotation angle. For example, the rotation angle of the adjusting screw with respect to the number of steps of 1 is 12.6 degrees, and the elevation distance of the platen when the angle is rotated is 0.0175 mm. Therefore, a required rotation angle can be obtained by multiplying the number of steps displayed on the display unit E by 12.6.

  Even if the rotation angle corresponding to the displayed number of steps can be read from the platen parallelism adjustment conversion table, it is not easy to accurately turn the adjustment screw 27 at the current position to the read rotation angle. However, as shown in FIG. 8, when the scale 30 having finely spaced radiation and power with a pitch of, for example, about 1 degree or 2 degrees is written around the adjustment screw, accurate adjustment is relatively easy. Screw rotation is possible. In that case, if each radiation of the scale represents the number of steps, it is only necessary to turn the adjustment screw by the number of scales that matches the displayed number of steps, so that the adjustment work can be facilitated.

  Since the number of steps of the S motor 11 of the platen lifting / lowering means B, which is the measured value of the platen, and the rotation angle of the adjusting screw have a linear relationship as in the above example, the CPU calculating means 34 further includes Multiply the number of steps, which is the tilt measurement value, by a fixed conversion factor (12.6 in the above example) to convert it to the rotation angle of the adjustment screw, and display the rotation angle that is the calculation result on the display unit E It can also be displayed.

  In this case, it is only necessary to rotate the adjustment screw 27 by the scale corresponding to the displayed numerical value, so that the parallelism can be adjusted more easily and accurately.

The block diagram which shows schematic structure of the platen parallelism adjustment apparatus of this invention. The front view of the principal part of a printer which shows the state in which a print head exists in the left side measurement position. The front view of the principal part of a printer which shows the state in which a print head exists in the right side measurement position. The perspective view of a platen support height adjustment means. The perspective view which shows an example of the detection means which detects that a platen reached | attained HP. The top view which shows an example of an adjustment screw mounting position and a display means. Detailed view of the display means. The enlarged view of the circle | round | yen X part of FIG. The flowchart which shows the operation | movement at the time of platen parallelism adjustment mode. The flowchart which shows the detail of platen parallelism measurement operation | movement.

A print head moving means 5 print head 7 motor 8 belt 9 ribbon mask B platen lifting means 10 platen 11 S motor (stepping motor)
12 Camshaft 13a Bracket 13b Bracket 14a, 14b Bearing 15 Eccentric cam 16 Friction clutch (torque limiter)
19 Cam follower C Platen position detection means (HP sensor)
20 Light-shielding plate 21 Photoelectric switch D Platen support height adjustment means 13b Bracket (adjustment plate)
24 support plate 27 adjustment screw 29 screw head 30 scale E display means 31a, 31b, 31c display element F CPU
32 Control means 33 Counting means 34 Calculation means

Claims (4)

A print head moving means for moving the print head in the print direction, and a platen extending parallel to the print head moving direction is moved up and down relative to the print head so that the print head is supported between the print head and the print medium supported by the platen. in a printer having a platen elevating means that to ensure a predetermined gap,
The platen elevating means includes a stepping motor, a camshaft that is supported at one end so as to be movable up and down, and is provided with a rotational force of the stepping motor via a friction clutch, a plurality of eccentric cams fixed to the camshaft, and the platen And a cam follower that is in contact with each eccentric cam provided in the
One end of the camshaft is supported so as to be movable up and down, a height adjusting means for adjusting the supporting height by rotation of an adjusting screw, a detecting means for detecting that the platen is moved to a home position, and the platen Means for counting the number of steps given to the stepping motor to move from the position in contact with the print head to the home position; and the platen when the print head is in the left measurement position. The number of steps given to the stepping motor to move from the abutting position to the home position and the platen when the print head is in the right measurement position are moved from the abutting position to the home position. Number of steps given to the stepper motor to Arithmetic means for obtaining a difference, or a calculation means for converting the rotation angle of more the adjusting screw the number of steps of the difference, the platen parallelism adjustment device comprising a display means for displaying the calculation result.   The platen parallelism adjusting device according to claim 1, wherein the display means displays the result of the computing means as a positive or negative sign and the number of steps or the numerical value of the rotation angle of the adjusting screw.   The platen parallelism adjusting device according to claim 2, wherein the display means is provided in the vicinity of the adjusting screw.   The adjustment screw has a negative engagement groove on the head, and the scale supporting the head of the adjustment screw has a step number or a rotation angle scale around the adjustment screw head. The platen parallelism adjusting device according to 1, 2, or 3.

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