JPS6184266A - Control for velocity of transfer of printing head - Google Patents

Abstract

PURPOSE:To determine a velocity of a printing head in parallel to a platen by detecting the thickness of a printing paper, by a method wherein a printing head is brought into contact with a printing paper by a stepping motor, and is returned to an initial position. CONSTITUTION:The printing paper 27 is fitted to the platen 26, and a predetermined number of pulses are inputted. Though the rotation of the stepping motor 24 is blocked and a step-out phenomenon occurs when the gap between a ribbon projector 3 and the paper 27 is reduced to zero, inputting of the pulses is continued until the predetermined number of pulses are completely inputted. Then, pulses for reverse rotation are inputted, and a sense lever 21 is detected by a detecting element. The position of a carriage 1 stopped is made to be the initial position of the printing head 2. Based on the number of pulses, a paper thickness corresponding to a pulse count previously stored in a memory part is read, and the absolute thickness of the paper 27 is detected. Simultaneously, a parallel moving velocity of the carriage 1 corresponding to the paper thickness stored in a ROM or the like is read by a controlling part, and a drive source is controlled to obtain a velocity of the carriage 1 suitable for the paper 27.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention is directed to a printer using a wire dot print head, by ensuring a platen gap of the print head suitable for the thickness of the print paper to be used. The present invention relates to a method of controlling the moving speed of a print head so that the moving speed of the print head is suitable for the thickness of the print head.

[Conventional technology]

A wire dot print head performs printing by colliding a plurality of wires at high speed with an ink ribbon coated with ink on printing paper placed on a platen.

For this purpose, a platen gap is provided at a predetermined distance between the print head tip and the platen.

If this platen gap is too small, the ink ribbon will rub against the printing paper and stain the printing paper surface, 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.

First, if the thickness of the print paper placed 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. In such cases, the platen gap must be adjusted to be larger.

As described above, as a technique for adjusting the platen gap for various thicknesses of printing paper, for example, Japanese Patent Application Laid-Open No. 51-1999.
-58130 and JP-A-52-1.06918, the former uses a pulse motor to move the print head to the print paper placed on a platen, brings the print head into contact with the print paper, and then uses the pulse motor to move the print head to the print paper placed on the platen. An appropriate amount of platen gap is secured by reversing the print head by a predetermined amount to separate the print head from the print paper. The latter is equipped with a light-emitting piece that always follows the surface of the printing paper placed on the platen with light contact, and a light-receiving piece that is fixed at a fixed position receives changes in the position of the light-emitting piece, and based on the measurement value, the print head is moved to the printing paper. An appropriate amount of platen gap is secured by moving the platen closer to or away from it by a predetermined amount.

The platen gap required for printing is secured as described above, but in today's world where high-speed printing is required, in order to reduce the amount of wire movement, the platen gap is set so that the tip of the wire is as close to the printing paper as possible. is desirable. Additionally, in order to perform high-speed printing, the print head must be moved at high speed parallel to the platen.

This movement of the print head is generally adjusted so that it can move as quickly as possible when the print paper placed on the platen is relatively thin and the wire returns from the platen quickly. .

Therefore, as the number of copies of printing paper increases, the total thickness of the printing paper becomes thicker and an air layer is formed between the printing papers, so when the wire collides with the platen through the printing paper,
The contact time between the wire and the printing paper becomes longer, and the return time of the wire becomes slower. When the head is moved, the wire of the print head gets caught on the print paper, causing the wire to bend or break.

Therefore, the platen gap must be adjusted to the thickness of the printing paper, and when the thickness of the printing paper exceeds a certain thickness, the moving speed of the print head must also be adjusted to become slower.

To this end, conventionally, a detection element that detects when the print paper has exceeded a certain thickness is provided independently from the above-mentioned adjustment mechanism for the platen gap and movement speed of the print head. Based on the detection signal, the moving speed of the print head is controlled to be slower than when the printing paper is thin.

[Problem that the invention seeks to solve]

As mentioned above, when performing high-speed printing, it is necessary to adjust the moving speed of the print head as well as the platen gap.
No. 10691.8, although it is possible to secure a Planan gap, does not detect the thickness of the printing paper being used and adjust the moving speed of the print head.

In addition, as described above, there is a method in which the detection element detects when the printing paper exceeds a certain thickness and adjusts the moving speed of the print head, but in this case, the detection element is provided independently. Therefore, there was a problem that the mechanism became complicated and increased in size.

[Failure to solve the problem]

In order to solve the above problems, the present invention uses a stepping motor to move the print head closer to or away from the print paper, determines the initial position of the print head, and moves the print head from this initial position. It consists of a detection means that detects the paper thickness of the printing paper by bringing it into contact with the printing paper and returning it to the initial position, and a control section that determines the parallel movement speed of the print head with respect to the platen based on the information of this detection means. ing.

[Effect]

According to the above-mentioned means, a certain number of pulses are input to the stepping motor, the print head is moved from an initial position to the printing paper placed on the platen and brought into contact with it, and after all of the above certain number of pulses are input, , input a pulse to reverse the stepping motor, move the print head away from the printing paper and return it to the initial position, count the number of input pulses when the stepping motor reverses at this time, and obtain paper thickness information based on this number of pulses. This information is stored in the memory unit in advance, and by reading this information, the paper thickness of the print paper is detected, and based on this detection information, an appropriate distance between the print paper and the print head is secured, and printing is performed on the platen. The translation speed of the head can be determined.

〔Example〕

Fig. 1 is a block diagram of a device control section according to an embodiment of the present invention, Fig. 2 is a perspective view of main parts of the device, Fig. 3 is a left side view in Fig. 2, and Fig. 4 is a right side view in Fig. 2. 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.

2 to 6, 1 is a carriage, 2 is a print head mounted on the carriage ring 1, 3 is a ribbon protector fixed to the carriage 1 and located in front of the print head 2, and 4 is a print head mounted on the carriage ring 1;
5 is an ink ribbon that runs between the tip of the print head 2 and the ribbon protector 3; 5 is a main shaft that supports the movement of the carriage 1, which is provided parallel to a platen (to be described later); and 6 is also an ink ribbon (to be described later), which is provided parallel to the platen. The main shaft 5 is a sub-shaft that supports the movement of the carriage 1. The main shaft 5 passes through the front of the carriage 1 so that the carriage 1 can slide, and the sub-shaft 6 abuts a rotatable roller at the rear end of the carriage 1. are in contact with each other.

1.8 is a side frame on both sides of the device, 9.10 is a square hole provided in each of the side frames 7.8, and both ends of the main shaft 5 are movably supported in the square holes 9 and 10. There is. The subshaft 6 is also rotatably supported by the side frame 7.8. 11,12
are links provided at both ends of the main shaft 5 and the 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. Reference numerals 15 and 16 indicate driven rollers provided on the links 11 and 12, and reference numerals 17 and 18 indicate springs provided on the side frames 7 and 8 from both ends of the main shaft 5, which urge the main shaft 5 in one direction to move the carriage 1. and moving it to one side. 19
．． 20 is a cam fixed to both ends of the subshaft 6, which rotates together with the subshaft 5 to connect the links 11, 1.
2 of the driven rollers 15, 16 and presses them, causing the links 11, 12' to move against the force of the springs 17, 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 moving position of the sense lever 21 and controls the print head 2; A detection element for detecting the initial position, 24 a stepping motor for rotationally driving the pulley 22, and 25 a belt stretched from the pinion of the motor 22 to the pulley 22.

26 is a platen, the platen 26 and the print head 2 face each other, and the main shaft 5 and the sub shaft 6
is arranged parallel to the platen 26. 28
is the printing paper mounted on the platen 26.

One embodiment of the present invention is constructed as described above, and its operation will now be described.

First, when the printing paper 27 is mounted on the platen 26, a predetermined number of pulses are input to the stepping motor 24, and the stemming motor 24 starts rotating. The pulley 22 is rotated by the hub belt 25 of the stepping motor 24.
is transmitted, the subshaft 6 is rotated by the pulley 22, and the cam 19.20 is rotated together with the subshaft 6,
The driven rollers 15, 16 of the link 11.12 are pressed to move the link 11.12 toward the platen 26 against the force of the spring 17.18. The main shaft 5 is moved toward the platen 26 by the links 11 and 12,
Together with this main shaft 25, the carriage 1 and the print head 2 are moved to the print paper 27, and the ribbon protector 3 and the print paper 27 are moved as shown in FIGS.
The gap between them is 0.

Here, the rotation of the stepping motor 240 is stopped and the stepping motor 24 loses synchronization, but this synchronization is ignored and continues until the predetermined number of pulse inputs is completed. When this fixed number of pulse inputs is completed, an input pulse is given to the stepping motor 24 to reverse its rotation, and the stepping motor 24f rotates in the opposite 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, causing the subshaft 6 to rotate in the opposite direction, and the cams 19 and 18 rotating together with the subshaft 6 also to rotate in the opposite direction. rotate to
The pressure on the driven rollers 15, 16 of the links 11, 12 is also gradually released.

Then, the spring 1 acting on the main shaft 5
According to 7.18, the main shaft 5 is connected to the link 11.12.
At the same time, it is moved in a direction away from the platen 26. , This reverse rotation of the stepping motor 24 is caused by the sense lever 21 rotating together with the subshaft 6 as shown in FIG.
moves to the position of the detecting element 23 and continues until it is detected by the detecting element 23. In this way, the platen 26
The position where the carriage 1 moves in the direction away from and stops is the initial position of the print head 2.

The number of pulses inputted when the stepping motor 24 rotates in reverse is counted by a control section (to be described later), and based on the counted number of pulses, the control section corresponds to the number of counted pulses stored in advance in the storage section. Read the paper thickness and print paper 2
Detect the absolute thickness of 7.

Thereafter, the number of pulses corresponding to the paper thickness detected as described above, which is stored in advance in the control section, is read out and inputted to the stepping motor 24, and the stepping motor 24 is rotated by the number of pulses to turn the printing hand 2. It is moved together with the carriage 1 to the platen 26 side using the above-described operating procedure. Note that the number of pulses corresponding to the paper thickness of the control section described above is the number of pulses so that the distance between the print paper 27 and the ribbon protector 3 is an appropriate amount when the print head 2 moves from the initial position to the platen 26 and stops. This is the number of pulses set to rotate the stepping motor 24.

With this, the platen gap in the print paper 27 is secured, and the distance between the print paper 27 and the wire of the print head 2 is adjusted to an appropriate amount.

Therefore, the wire collides with the printing paper 27 with an appropriate pressure, and the best printing quality can be obtained.

Here, if the paper thickness of the printing paper 27 shows a change of more than a certain paper thickness compared to the paper thickness used last time, the printing movement speed of the print head 2, which moves parallel to the platen 26 together with the carriage 1, will cause problems. Therefore, the speed must be adjusted to an appropriate level.

For this purpose, the control section detects the absolute thickness of the printing paper 27, and at the same time reads out and determines the parallel movement speed of the carriage 1 relative to the platen 26 for the thickness of the paper stored in advance in a ROM etc. The carriage 1 is moved at a speed suitable for the printing paper 27 by controlling the drive source.

The moving speed of the carriage 1 that moves the print head 2 is, as explained above, the moving speed of the carriage 1 is generally determined to be as fast as possible based on the conditions of thin printing paper. If the thickness of the printing paper exceeds the thickness of the paper, the contact time between the printing wire and the printing paper will be longer, and the movement of the carriage 1 will damage the printing wire. Therefore, the moving speed of the carriage 1 should be adjusted to match the thicker printing paper. Conversely, when the paper thickness changes from thick to thin, the speed should be returned to the original high speed.

Next, a control section that controls the operation of the above-mentioned mechanism is shown in FIG. 1, and its control procedure will be explained.

Note that parts that are the same as those described above are designated by the same reference numerals as those shown above.

FIG. 1 is a block diagram showing the control unit. 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, and the platen gap adjustment mechanism of the print head is rotated. The section 30 is driven and the ribbon protector 3 and the printing paper 27 are brought into contact with each other.

Next, a pulse for causing the stepping motor 24 to rotate in the opposite direction is output from the stepping motor drive signal circuit 28 to the stepping motor drive circuit 29, and the stepping motor 24 rotates in the opposite direction to the above, thereby moving the print head 2 together with the carriage 1 to the initial position. Return to. This is continued until the detection element 23, which detects the initial position, operates.

In order to reverse the stepping motor 24, the number of pulses output from the stepping motor drive signal circuit 28 is detected by the pulse counter 31, and the paper thickness corresponding to the detection result of the pulse counter 31 stored in the storage section 32 in advance is At the same time, the number of pulses is read out and the information is output to the stepping motor drive signal circuit 28 and the printing speed setting circuit 33, respectively.

The stepping motor drive signal circuit 28 operates the stepping motor drive circuit 29 to rotate the stemming motor 24, operates the platen gap adjustment mechanism 30 of the print head, and moves the print head 2 together with the carriage 1 to the platen 26 again. This ensures a proper platen gap and a proper distance between the printing paper 27 and the wire.

On the other hand, the print speed setting circuit 33 operates the print head lateral movement section 34 to set the speed at which the print head 2 moves parallel to the platen 26 together with the carriage 1 to an appropriate speed.

In the embodiment described above, the paper thickness of the printing paper 27 is detected by detecting whether a direction pulse is input to the stepping motor 24 while the printing hand 2 contacts the printing paper 27 and returns to the initial position. However, in addition to this, after the print head 2 contacts the print paper 27, the stepping motor 2
It is also possible to detect the paper thickness by detecting whether or not the direction pulse 4 is out of step.
Since the paper thickness can also be detected by a change in the contact pressure of the contact member against the printing paper 27, the present invention is not limited to the paper thickness detection means for the printing paper 2T according to the above-described embodiment.

〔Effect of the invention〕

As explained above, in the conventional apparatus, a detection means for detecting the paper thickness of the printing paper placed on the platen was provided separately from the platen gap of the print head and the movement adjustment mechanism of the printing stop. The thickness of the print paper is detected by the platen gap, that is, the movement of the print head to ensure the distance between the print head and the print paper, and the speed of movement of the print head is adjusted based on the detected information. Therefore, no special paper thickness detection means is required, which has the effect of simplifying the device and promoting miniaturization.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a device control unit according to an embodiment of the present invention, FIG. 2 is a perspective view of essential parts of the device, FIG. 3 is a left side view in FIG. 2, and FIG. 4 is a right side view in FIG. 2. 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 24... Step = 16- Tsuping motor 26... Platen 27... Print paper

Claims (1)

[Claims] 1. In a method for controlling the movement speed of a print head to suit the thickness of the print paper, the distance between the print head and the print paper is adjusted by a spacing adjustment mechanism between the print head and the print paper. A method for controlling the moving speed of a print head, characterized by detecting the thickness and controlling the moving speed of the print head based on the information. 2. In claim 1, the stepping motor is rotated in the forward direction with a predetermined pulse to advance the print head toward the printing paper, and then the stepping motor is reversed to return the print head to a predetermined position to move the print head. Counts how many direction pulses are required to return to a predetermined position, and reads the appropriate spacing movement speed of the print head according to the thickness of the printing paper from the storage device, and controls the spacing motor based on this read value. A method for controlling the movement speed of a print head, characterized in that the spacing speed of the print head is set in accordance with the paper thickness of printing paper set on a platen.