JPH0542356B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention, in a printer using a wire dot print head, secures a platen gap of the print head suitable for the thickness of the print paper used, and The present invention relates to a method for controlling the moving speed of a printing head so as to obtain a moving speed of the printing head suitable for the thickness.

[Conventional technology]

The wire dot print head prints by colliding multiple wires at high speed with an ink ribbon on the printing paper set on the platen.
For this purpose, a platen gap is provided at a predetermined distance between the print head tip and the platen.

If the platen gap is too small, the ink ribbon will rub against the print paper, staining the surface of the print paper, and if it is too large, the collision force of the wire will be small, resulting in problems such as a decrease in print density. Must be set appropriately.

In other words, if the thickness of the print paper set on the platen changes, for example if it becomes thicker, the print paper surface will move closer to the ink ribbon and come into contact with it or press the ink ribbon against the print head. must be adjusted to increase the platen gap.

Techniques for adjusting the platen gap for various thicknesses of printing paper are disclosed in, for example, Japanese Patent Laid-Open Nos. 51-58130 and 1982-106918.

The former is achieved by rotating the pulse motor in the forward direction to move the print head forward, bringing the tip of the print head into contact with the print paper, and then rotating the pulse motor in the reverse direction by a predetermined amount to move the print head backward and away from the print paper. Ensures appropriate platen gap.

In addition, the latter is equipped with a light-emitting piece that always follows the surface of the printing paper set on the platen with light contact, and changes in the position of the light-emitting piece are received by a light-receiving piece fixed at a fixed position, and the print head is adjusted based on the measured value. Proper platen gap is ensured by moving it closer to or farther away from the printing paper.

In this way, there is a technology to ensure an appropriate platen gap for the thickness of the printing paper, but in today's world where high-speed printing is required, in order to reduce the amount of movement of the wire in the print head, it is necessary to attach the tip of the wire to the printing paper. It is desired to move the print head as close as possible and to move the print head parallel to the platen at high speed.

This space movement speed of the print head is limited by the relatively thin thickness of the print paper set on the platen.
It is common to adjust the wire to move as fast as possible in a state where it returns quickly from the platen.

On the other hand, as the number of copies of printing paper increases, the total paper thickness of the printing paper becomes thicker, and an air layer is created between the printing papers, so when the wire collides with the platen through the printing paper, the wire and the printing paper The contact time with the wire will be longer and the return time of the wire will be slower.

Therefore, in this state, if the print head is moved through space at a speed adjusted based on the condition that the print paper set on the platen is thin as described above, the wire of the print head will get caught in the print paper, causing the wire It got bent or broken.

Therefore, the platen gap must be adjusted to the thickness of the printing paper, and if the printing paper is thicker than a certain thickness, the moving speed of the printing head must also be adjusted to slow down.

To this end, conventionally, a detection element for detecting when the printing paper has exceeded a certain thickness was provided independently from the above-mentioned adjustment mechanisms such as the platen gap and movement speed of the print head, and the detection element detected The signal controls the print head movement speed to be slower than when the printing paper is thin.

[Problem that the invention seeks to solve]

However, among the above-mentioned conventional technologies, the technology of JP-A No. 51-58130 and the technology of JP-A-52-106918 can secure the platen gap, but cannot detect the thickness of the printing paper being used. Since the moving speed of the print head is not adjusted, it is difficult to print well on both thick and thin printing paper that requires a large number of copies. There is.

In addition, in the method of adjusting the moving speed of the printing head by detecting when the printing paper exceeds a certain thickness using a detection element, the detection element is provided independently, which makes the mechanism complicated. Along with this, there was the problem of increasing size.

[Means for solving problems]

In order to achieve this object, the present invention has a tip facing a platen through a ribbon protector, and moves forward and backward with respect to the platen together with the ribbon protector by a stepping motor.
In the method for controlling the movement speed of a printing head that moves in a space parallel to the platen by a spacing motor, the printing head is advanced by applying a predetermined number of forward rotation pulses to the stepping motor, and the ribbon protector is moved forward. The printing head is brought into contact with the printing paper set on the platen, and then a pulse for reverse rotation is given to the stepping motor, thereby retracting the print head to the initial position, and at the same time retracting the pulse for reverse rotation required for this retraction. The number of pulses is counted by a counting means, the counted value is compared with the number of pulses stored in a recording means to detect the paper thickness of the printing paper, and the platen and the tip of the printing head are The number of forward rotation pulses to obtain an appropriate platen gap between the two is read from the storage means, and the read forward rotation pulses are applied to the stepping motor to advance the print head, and the detected paper thickness is An appropriate space movement speed of the print head is read from the recording means, and if the printing paper is thick, the print head space movement speed is slow, and if the printing paper is thin, the printing is slow. The spacing motor is characterized in that the spacing motor is controlled so that the space movement speed of the head becomes faster.

[Effect]

The present invention having such a configuration can detect the paper thickness of the print paper set on the platen by moving the print head forward and backward to obtain an appropriate platen gap, so there is no need for any special paper thickness detection means. Therefore, it is possible to simplify and downsize the device, and also to correspond to the detected paper thickness, if the paper thickness is thick, the print head space movement speed is slow, and if the paper thickness is thin, the print head space movement speed is slow. Since the spacing motor is controlled so as to speed up printing, it is possible to perform good printing without bending or damaging the wire of the printing head.

〔Example〕

Examples will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an example of a control system for implementing the print head movement speed control method according to the present invention, and FIG. 2 is a perspective view of essential parts of a printer to which the print head movement speed control method of the present invention is applied. Figure, 3rd
The figure is a left side view of FIG. 2, FIG. 4 is a right side view of FIG. 2, FIG. 5 is a side sectional view of FIG. 2, and FIG. 6 is a right side view showing the initial position of the print head. .

First, an explanation will be given using Figures 2 to 6. In these figures, 1 is the carriage, 2 is the print head mounted on the carriage 1, and 3 is the ribbon protector located in front of the print head 2 fixed to the carriage 1. , 4 is an ink ribbon running between the tip of the print head 2 and the ribbon protector 3.

5 is a main shaft that supports the carriage 1 and guides its movement; 6 is also a main shaft 5;
Similarly, it is a subshaft that supports the carriage 1 and guides its movement, and both shafts 5 and 6 are provided parallel to the platen, which will be described later, and the main shaft 5 is located at the front of the carriage 1. The carriage 1 slides therethrough, and the subshaft 6 abuts a rotatable roller provided at the rear end of the carriage 1.

The printing head 2, along with the carriage 1 and ribbon protector 3, is moved by a spacing motor (not shown) along a main shaft 5 and a subshaft 6 in a direction parallel to the platen.

7 and 8 are a pair of left and right side frames, 9 and 10
are square holes provided in both side frames 7 and 8, and both ends of the main shaft 5 are movably supported in the square holes 9 and 10, and the subshaft 6 is rotatably supported in the side frames 7 and 8. Possibly supported.

Reference numerals 11 and 12 denote links provided at both ends of the main shaft 5 and subshaft 6, respectively, and are rotatably attached to the main shaft 5 and movably attached to the subshaft 6 through elongated holes 13 and 14. It is being

15 and 16 are driven rollers provided on the links 11 and 12; 17 and 18 are springs passed between both ends of the main shaft 5 and posts provided on the side frames 7 and 8;
Reference numeral 16 urges the main shaft 5 toward the rear side of the square holes 9 and 10 to attach the print head 2 together with the carriage 1.
works to push back.

Cams 19 and 20 are fixed to both ends of the subshaft 6, rotate together with the subshaft 5, contact the driven rollers 15 and 16 of the links 11 and 12, and press the cams so that the links 11 and 12 are moved by the springs 17 and 16, respectively. It functions to move against the force of 18.

21 is a sense lever fixed to one end of the subshaft 6 together with the cam 20; 22 is a pulley fixed to the end of the subshaft 6 together with the cam 19; 23 is a pulley that detects the movement position of the sense lever 21 and adjusts the initial position of the print head 2; 24 is a stepping motor that rotationally drives the pulley 22, and 25 is a belt stretched from the pinion of the stepping motor 24 to the pulley 22.

26 is a platen, and the tip of the print head 2 faces the platen 26 with a ribbon protector 3 interposed therebetween.

27 is a printing paper set on the platen 26.

Next, the detection of the thickness of the print paper 26, the setting of the platen gap, and the space movement of the print head 1 using the above-described configuration will be explained.

First, when the printing paper 27 on the platen 26 is set, a predetermined number of pulses are sequentially input to the stepping motor 24, and the stitching motor 24 starts rotating forward.

The rotation of this stepping motor 24 is controlled by the belt 2.
5 to the pulley 22, and the subshaft 6 is rotated by the pulley 22, so the cams 19 and 20 rotate together with the subshaft 6, pressing the driven rollers 15 and 16 of the links 11 and 12, and the link 11 and 12 are advanced toward the platen 26 against the force of springs 17 and 18.

These links 11, 12 push the main shaft 5 toward the platen 26, so that together with the main shaft 25, the carriage 1 and the print head 2 move forward toward the printing paper 27, as shown in FIGS. 3 and 4. The ribbon protector 3 comes into contact with the printing paper 27 as shown in FIG.

At this point, since the carriage 1 and the print head 2 are prevented from moving forward, the stepping motor 24 will step out of step, but this step out will be ignored and the stepping motor 24 will continue to operate until the specified number of pulse inputs are completed.
rotation is performed.

When this fixed number of pulse inputs is completed, a pulse is then applied to the stepping motor 24 to reverse its rotation, causing the stepping motor 24 to rotate in the reverse direction.

This reverse rotation of the stepping motor 24 is transmitted from the belt 25 to the pulley 22 and then to the subshaft 6, and since the subshaft 6 rotates in the opposite direction, the cams 19 and 20 that rotate together with the subshaft 6 also rotate in the same direction as described above. It rotates in the opposite direction, and the pressure of the driven rollers 15, 16 of the links 11, 12 is gradually released.

Along with this, the springs 17 and 18 acting on the printing shaft 5 are restored, and the printing shaft 5 moves in a direction away from the platen 26 together with the links 11 and 12 due to the urging force, so that the carriage 1 and the printing head 2 move backward. .

This retraction of the carriage 1 and print head 2 is
As shown in FIG. 6, the sense lever 21, which rotates together with the subshaft 6, moves to the position of the detection element 23 until it is detected by the detection element 23.

When the sense lever 21 is detected by the detection element 23, the stepping motor 24 is stopped from rotating in reverse, thereby stopping the print head 2 together with the carriage 1 at the initial position.

The number of pulses required from the start of reverse rotation of the stepping motor 24 to the time of stopping at this time is counted by a counting means of the control system, which will be described later, and based on this counted number of pulses, a count is pre-stored in the storage means. Read the paper thickness corresponding to the number of pulses and print paper 2.
Detect the absolute thickness of 7.

Thereafter, the number of pulses for obtaining an appropriate platen gap corresponding to the detected paper thickness stored in advance in the storage means is read out, and that number of pulses for forward rotation are input to the step pin motor 24 to start the step. By rotating the ping motor 24 in the forward direction, the print head 2 and the carriage 1 are advanced from the initial position toward the platen 26 in the same operating procedure as described above.

This ensures a proper platen gap, so that when the wire of the print head 1 is driven, the wire collides with the print paper 27 with the proper pressure to obtain the best print quality.

On the other hand, if the paper thickness of the print paper 27 detected as described above has changed by more than a certain value compared to the one used last time, the space movement speed of the print head 2 must be adjusted accordingly.

For this purpose, the control system detects the absolute thickness of the printing paper 27, and at the same time reads out the appropriate space movement speed of the printing head 2 for the detected paper thickness stored in advance in the storage means, and controls a spacing motor (not shown). , move the print head 1 through the space at an appropriate speed.

As explained above, the appropriate space movement speed for the print head 2 is that the movement speed of the carriage 1 is generally set to be as fast as possible for thin printing paper. When the paper thickness exceeds a certain paper thickness, the wire and printing paper 2
7 and damage the wires due to the movement of the print head 2.
The speed of movement of the paper is slowed down to match the thickness of the printing paper, and conversely, when the thickness of the paper changes from thick to thin, it is returned to its original high speed.

Next, the control system shown in FIG. 1 for controlling the operation of the mechanism described above will be explained.

In FIG. 1, the same parts as those explained in FIGS. 2 to 6 are designated by the same reference numerals.

First, a certain number of pulses are output from the stepping motor drive signal circuit 28 to the stepping motor drive circuit 29, the stepping motor 24 rotates forward, and the platen gap adjustment mechanism 30 of the print head is driven. moves forward together with the carriage 1 and the ribbon protector 3, and the ribbon protector 3 comes into contact with the printing paper 27 set on the platen 26.

The platen gap adjustment mechanism 30 of the printing head is composed of 5 to 25 parts as shown in FIGS. 2 to 6.

Next, stepping motor drive signal circuit 2
8 outputs a pulse to reversely rotate the stepping motor 24 to the stepping motor drive circuit 29, thereby causing the stepping motor 24 to rotate in the reverse direction and move the print head 2 together with the carriage 1 and ribbon protector 3 to the initial position. make it retreat.

At this time, the print head 2 is positioned at the initial position by the detection element 23 detecting the sense lever 21 and stopping the reverse rotation of the stepping motor 24 based on the output thereof, as described above.

On the other hand, in order to reversely rotate the stepping motor 24, the number of pulses output from the stepping motor drive signal circuit 28 is counted by a pulse counter (counting means) 31, and the number of pulses is counted by a pulse counter (counting means) 31, The paper thickness is detected by comparing the paper thickness value corresponding to the counted value of the pulse counter 31, and the number of pulses for forward rotation to obtain an appropriate platen gap for the detected paper thickness is stored in the memory section. 32 and outputs it to the stepping motor drive signal circuit 28. Furthermore, the space speed of the printing head 2 appropriate for the detected paper thickness is read from the storage section 32 and output to the printing speed setting circuit 33.

As a result, the stepping motor drive signal circuit 28 operates the stepping motor drive circuit 29 to rotate the stepping motor 24 in the forward direction by the number of pulses mentioned above, thereby operating the platen gap adjustment mechanism 30 of the print head, thereby causing the carriage 1 and Print head 2 integrated with ribbon protector 3
At the same time, the print speed setting circuit 33 operates the print head lateral movement unit 34 using the spacing motor described above to move the print head 2 to the ribbon protector 1 and the ribbon protector 3. Move the space together at an appropriate speed.

In the embodiment described above, the number of pulses required for the rotation of the stepping motor 24 from when the ribbon protector 3 located at the tip of the print head 2 comes into contact with the print paper 27 until the print head 2 returns to the initial position is determined by the counter. Although the paper thickness of the printing paper 27 is detected by counting, the present invention is not limited to this. For example, after the ribbon protector 3 comes into contact with the printing paper 27, the stepping motor 24 steps out by how many pulses. It is also possible to detect the paper thickness by counting the number of print sheets 27, or by providing a contact member that comes into contact with the print paper 27, and detecting the paper thickness by changing the contact pressure of this contact member against the print paper 27. It is.

〔Effect of the invention〕

As explained above, the present invention advances the printing head by applying a predetermined number of forward rotation pulses to the stepping motor to bring the ribbon protector into contact with the printing paper set on the platen,
Next, the printing head is retreated to the initial position by applying pulses for reverse rotation to the stepping motor, and the number of pulses for reverse rotation required during this retreat is counted by a counting means, and the counted value is stored. A forward rotation pulse that detects the paper thickness of the printing paper by comparing it with the number of pulses stored in the means, and obtains an appropriate platen gap between the platen and the tip of the print head for the detected paper thickness. reading the number from the storage means, applying the read pulse for forward rotation to the stepping motor to move the print head forward;
reading out from the storage means an appropriate space movement speed of the print head for the detected paper thickness;
The spacing motor is controlled so that when the printing paper is thick, the space movement speed of the print head is slow, and when the printing paper is thin, the space movement speed of the print head is fast. ing.

Therefore, according to this, the paper thickness of the print paper set on the platen can be detected by the forward and backward movement of the print head to obtain a proper platen gap, so a special paper thickness detection means is not required.
This has the effect of simplifying and downsizing the device, and also corresponds to the detected paper thickness.If the paper thickness is thick, the printing head space movement speed is slow, and if the paper thickness is thin, the printing head space movement speed is slow. Since the spacing motor is controlled to increase the moving speed, it is also possible to perform good printing without bending or damaging the print head wire.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a control system for implementing the print head movement speed control method according to the present invention, and FIG. 2 is a perspective view of essential parts of a printer to which the print head movement speed control method of the present invention is applied. Figure, 3rd
The figure is a left side view of FIG. 2, FIG. 4 is a right side view of FIG. 2, FIG. 5 is a side sectional view of FIG. 2, and FIG. 6 is a right side view showing the initial position of the print head. . 1...Carriage, 2...Print head, 3...
Ribbon protector, 23...detection element, 24...
Stepping motor, 26...Platen, 27...
...Print paper, 31...Pulse counter, 32...
Memory department.

Claims (1)

[Claims] 1. The leading end faces the platen through a ribbon protector, moves forward and backward with respect to the platen integrally with the ribbon protector by a stepping motor, and moves in a direction parallel to the platen by a spacing motor. In the method for controlling the movement speed of a printing head that moves in space, the printing head is advanced by applying a predetermined number of forward rotation pulses to the stepping motor, and the ribbon protector is brought into contact with printing paper set on a forward platen. Then, by applying reverse rotation pulses to the stepping motor, the print head is retracted to the initial position, and the number of reverse rotation pulses required during this retraction is counted by a counting means, and the count is calculated. The paper thickness of the printing paper is detected by comparing the numerical value with the number of pulses stored in the storage means, and an adjustment is made to obtain an appropriate platen gap between the platen and the tip of the print head for the detected paper thickness. The number of rotation pulses is read from the storage means, and the read forward rotation pulses are applied to the stepping motor to advance the print head, and the print head is moved by an appropriate space for the detected paper thickness. The speed is read from the storage means, and when the printing paper is thick, the printing head space movement speed is slow, and when the printing paper is thin, the printing head space movement speed is fast. A method for controlling the moving speed of a printing head, comprising controlling the spacing motor.