JPH02113979A - Dot printer - Google Patents

Abstract

PURPOSE:To maintain a space between a printing head and printing paper so that they are not caught by each other by determining the thickness of the printing paper based on the results of the difference between the number of energized pulses which are entered into a pulse motor in a drive mechanism during the backward movement of a mobile element from the printing paper to a detection element when the paper is loaded and the number of energized pulses during the backward movement of the mobile element from a platen to the detection element when the paper is not loaded. CONSTITUTION:A carriage assembly 3 is moved backward to a detection element 13 from a state where a contact element 7 is kept in contact with a platen 2 to which printing paper 16 is not attached. During this backward movement, the number of energized pulses which are entered into a pulse motor 8 by a controller 15 is counted. Next the printing paper 16 is attached to the platen 2, and the carriage assembly 3 is moved backward from a state where the tip of the contact element 7 is kept in contact with the external surface of the printing paper 1. Then during this backward movement, the number of energized pulses which are entered into the pulse motor 8 by the controller 15 is measured. After this, the thickness of the printing paper is measured with the controller 15 based on the measured number of pulses in the case of the former and that in the case of the latter.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Field of Application) The present invention relates to a dot printer device such as a wire dot printer.

(Prior Art) A wire dot printer is equipped with a print head having a large number of print wires, and prints by driving the print wires installed in the print head to collide with print paper loaded on a platen. By moving the print head laterally along the length of the platen, continuous printing can be performed on the print paper. This printer device is widely used as a printer in various devices because it can operate at high speed.

Therefore, in this dot printer device, when the printing head is moved horizontally or when the printing paper is fed, it is necessary to prevent the printing head from getting caught on the printing paper and causing the printing paper to break or the printing head to be damaged. In order to prevent the print head from drawing on the print paper, a predetermined size is set between the tip of the print head and the outer surface of the print paper, taking into account variations in the thickness of the print paper. It is necessary to position them with an interval of . Therefore, the print head must be positioned at a distance from the platen that takes into account the thickness of the print paper and the distance from the print paper. However, the overall thickness of printing paper varies depending on the paper quality such as Ql ('!O), the number of sheets, and the paper thickness per sheet. The position is adjusted by moving it back and forth with respect to the platen to ensure the distance between it and the platen, that is, the distance between it and the printing paper 81.

In conventional dot printers, the following steps are taken to adjust the position of the print head relative to the platen in accordance with the thickness of printing paper loaded on the platen.

That is, in this dot printer device, a movable body equipped with a print head can be moved back and forth with respect to a platen by a drive mechanism, and the movable body is advanced by a drive mechanism (I to 1) to print paper with a print head loaded on the platen. Then, move the movable body away from the printing paper and move it backwards by a distance corresponding to the predetermined size interval, and touch the platen by a distance of χ・1 (thickness of the printing paper x print head). The position is adjusted so as to ensure the distance between the printing paper and the printing paper.FIG. 4 is a flowchart showing the order of this operation.

(Problems to be Solved by the Invention) However, the dot printer device having such a function has the following problems.

In other words, when the printing paper is made with its paper fibers corrected and brought into contact with the printing paper, the printing paper is pressed by the print head and is elastically compressed in the thickness direction. Thereafter, when the print head is released from the printing paper, the pressing force is released and the printing paper returns to its original thickness due to its elasticity. However, in conventional devices, the print head moves backward by a predetermined amount from the position where the print head contacts and presses the print paper to adjust the position and secure the space between the print head and the print paper. However, in reality, when the print head is removed from the print paper, the print paper returns to its original thickness due to its elasticity. For this reason, the size of the gap between the print paper and the print head after elastic restoration and the position at which the print head is moved backward by a predetermined amount based on the position where the print paper is compressed by contacting the print paper are determined. Unlike the size of the gap between the printing paper and the print head obtained by performing the adjustment, the former spacing is smaller than the spacing between the rear stones by the elastic recovery of the printing paper. Therefore, in conventional devices, even if the print head is intended to be spaced apart from the print paper by a predetermined distance, in reality, the predetermined spacing is not secured to account for variations in the thickness of the print paper; When moving the print head laterally or feeding the print paper, the print paper may get caught on the tip of the print head, causing the print paper to be cut or the print head to be damaged.

In other words, in the conventional device, the total thickness of printing paper is A11l.
Since the position of the print head is not adjusted by L, but only by mechanical operation of the print head, the position of the print head relative to the platen, that is, the print paper, is adjusted by taking into consideration the elastic deformation of the print paper. Adjust properly
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The present invention has been made based on the above-mentioned "1." It is an object of the present invention to provide a dot printer device that can properly adjust the position of the dot printer by placing it on the platen.

[Configuration of the Invention (Means for Solving the Problem) In order to achieve the above object, the dot printer device of the present invention includes a movable body equipped with a print head, and a movable body that uses a movable force obtained by rotation of a pulse motor. a drive mechanism that moves forward in a direction approaching the platen and moves backward in a direction away from the platen; and a drive mechanism that is provided at a position apart from the platen and moves backward from the platen when the moving body passes. A detection element detects this, and when printing paper is loaded on the platen, the movable body moves backward from the printing paper to the detection element, and during this backward movement, inputs an input to the pulse motor of the drive mechanism. Count the number of excitation pulses 1, this total is 4-
The number of one pulse is compared with the number of excitation/malus input to the pulse motor of the drive mechanism while the movable body moves backward from the platen to the detection element when no printing paper is loaded on the platen. Find the difference, and calculate the difference.

(Function) First, the drive mechanism moves the movable body backward from the platen by a predetermined amount without loading printing paper on the platen in advance, that is, the number of excitation pulses input to the pulse motor of the moving mechanism reaches a predetermined number. A detection element is provided at the position. Then, with the printing paper loaded on the platen, the drive mechanism moves the movable body backward from the printing paper to the detection element. The detection element detects this backward movement of the moving body, and calculates the number of excitation pulses input to the pulse motor of the drive mechanism during the backward movement up to that point.
By comparing the number of one pulse with the number of pulses when no printing paper is loaded, which is already a total of Δl11, the thickness of the printing paper can be determined with high accuracy. Therefore, based on this measurement result, the print head should be positioned and circumferentially spaced from the platen at an appropriate distance that takes into account the elastic deformation of the print paper depending on the thickness of the print paper. koto i”J
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(Example) An embodiment of the present invention will be described below with reference to the drawings.

A platen 2 for inserting and holding printing paper is attached to one end of the side plates 1, 1, which are arranged parallel to each other with a gap between them. Further, a carriage assembly 3 which is a moving body is provided between the side plates 1 and 1, and this carriage assembly 3
is freely movable in the axial direction (in the axial direction of the platen 2) by a guide shaft 4 which is fixed by hanging over the side plates 1, 1, and an eccentric shaft 5 which is rotatably supported by the side plates 1, 1. 1 [is supported. A print head 6 is mounted on the carriage assembly 3 on the platen 2, and an abutment element 7 is integrally provided facing the platen 2. The carriage assembly 3 is moved along a guide shaft 4 and an eccentric shaft 5 by a machine (not shown).The rotation of this pulse motor 8 is controlled by a controller 15, which will be described later. A gear 9 is attached to the gear shaft of this pulse motor 8, and a gear 12 is attached to one end of the eccentric shaft 5. When the toothed motor 8 is driven to rotate, the rotation is caused by gears 9 and 12.
．． The eccentric shaft 5 rotates by transmitting rotation through 11.12,
The carriage assembly 3 is tilted against the platen 2 and moved forward or backward with a stroke corresponding to the amount of eccentricity of the eccentric shaft 5, depending on the direction of the rotation axis of the eccentric shaft 5. The pulse motor 8 is also provided with a clutch (not shown) that connects the output shaft of the motor and the gear shaft to which the gear 9 is attached to transmit rotation.

This clutch performs rotation transmission when the negative 6:f applied to the gear rotation shaft is below a certain level,
It is of a type that cuts off rotation transmission from the motor output shaft to the gear shaft when a larger negative 6I is applied. In other words, the load applied to the carriage assembly 3 acts on the gear shaft of the clutch equipped on the pulse motor 8 via the eccentric shaft 5 and the gears 12, 11, 10, 9, and the load applied to this gear shaft is If the value is larger than a predetermined value, the rotation transmission from the output shaft of the pulse motor 8 to the gear shaft is interrupted by the action of the clutch.

Further, a detection element 13 is mounted on one side plate 1 at a position set back from the platen 2 by a predetermined distance. The detection element 13 is installed at a position where the detection head 6 of the carriage assembly 3 contacts the platen 2 on which no printing paper 16 is loaded, and from that position a predetermined number of excitation pulses are input to the pulse motor 8. This is the position where the carriage assembly 3 is moved backward by rotationally driving the pulse motor 8. That is, by setting the number of excitation pulses input to the pulse motor 8 in advance,
The detection element 13 is mounted at a position at a distance corresponding to the number of pulses. The detection element 13 detects when the movable body 3 moves backward to the detection element position and outputs a detection signal to the controller 15. Detection element 1
3 specifically includes, for example, the light emitting section 13a and the light emitting section ff1S.
13a, and a light receiving section 13b that receives the light emitted from the light receiving section 13a. In order to notify the detection element 13 that the carriage assembly 3 has moved backward, an elongated hole [4] having a predetermined length is formed along the circumferential direction in the gear 12 attached to the eccentric shaft 5. 3 retreats from the platen 2 to the detection element 13, the elongated hole 14 is located between the light emitting part 13a and the light receiving part 13b, allowing light from the light emitting part 13a to reach the light receiving part 13b, and the carriage When the assembly 3 retreats to the detection element 13, the elongated hole 14 moves due to the rotation of the gear 12 and is removed from the detection element 13, causing the light emitting part 1 to move.
The light from 3a is blocked by the gear 12 and does not reach the light receiving section 13b, so that the light receiving section 13b outputs a (signal) to the controller 15.

In addition, the controller 15 outputs an excitation pulse to the pulse motor 8 to control the drive of the motor, and also controls when the printing paper 16 is not loaded on the platen 2 and when the printing paper 16 is loaded on the platen 2. In each case, the number of excitation pulses input to the pulse motor 8 for the backward movement of the carriage assembly 3 is calculated by comparing the two at AP)L. It also receives a detection signal from the detection cable 13.

The operation of the dot printer device configured as described above will be explained.

First, an excitation pulse is input from the controller 15 to the pulse motor 8 to drive the motor to rotate, and the carriage assembly 3 is moved forward from the detection cable 13 to the platen 2 on which the printing paper 16 is not loaded. Abutting element-7-7 is brought into contact. This stops the forward movement of the carriage assembly 3. In this case, the pulse motor 8 is overloaded and rotation from the pulse motor 8 is cut off by the action of the clutch (
After that, the pulse motor 8 is rotated in the reverse direction to move the carriage assembly 3 backward to the detection element 13 from the state where the contact element 7 is in contact with the platen 2. During this backward movement, the controller 15 counts the number of excitation pulses input to the pulse smoke 8. When the carriage assembly 3 moves backward and reaches the detection element 13, the detection element 13 detects this and outputs it to the controller 15, and the controller 15 that receives this signal stops counting the excitation pulses. The number of input excitation pulses from the platen 2 to the detection probe 13 is measured. Do this work in advance. That is, as described above, the detection element 13 is mounted in advance at a position that is set back a predetermined distance corresponding to a predetermined number of pulses from the platen 2 on which the printing paper 16 is not loaded.

Next, the printing paper 16 is mounted on the platen 2.

Then, as in the case described above, the pulse motor 8 is rotationally driven to move the carriage assembly 3 forward, and the tip of the contact cable 7 is brought into contact with the outer surface of the printing paper 16. In this case as well, the movement of the carriage assembly 3 is stopped and the carriage assembly 3 enters the decoupled state, as in the case described above.

Thereafter, the carriage assembly 3 is moved backward by the rotational drive of the pulse motor 8 to separate the print head 6 from the print paper 16. During this backward movement, the 1111 starvation device 15 measures the number of excitation pulses input to the pulse motor 8, and when the carriage assembly 3 reaches the detection element 73, the detection element 13
The counting of the controller 15 is stopped by a signal output from the controller 15.

Then, the controller 15 calculates the former side pulse number and the latter total Apj pulse number based on the following formula, and as a result, the thickness of the printing paper 16 inserted into the platen 2 is measured. .

Thickness of printing paper (■) - [(Number of measured pulses per pulse when printing paper is loaded - Number of pulses measured when printing paper is not loaded)] x (Amount of carriage assembly movement per pulse) To automatically and accurately measure the thickness of printing paper 16 to be printed. This measurement result is displayed by providing a display section on the controller 15, for example.

Then, based on the thickness of the printing paper 16 obtained by this measurement, since the contact element 7 presses the printing paper 16 roughly, the amount of restoration due to the elasticity of the printing paper 16 when the pressing cord 7 is released is calculated. The size of the interval at which the print head 6 and the print paper 16 will not be caught is set in consideration of the printing purpose. Then, the distance between the print head 6 and the platen 2 is set to ensure this distance, and the position of the print head 6 is adjusted.
That is, the position of the carriage assembly 3 is adjusted.

This position adjustment of the print head 6 is performed by calculating the spacing and the like using the controller 15, and further by moving the controller 15 by pulse reduction.

The order of these operations is shown in the flowchart shown in FIG.

FIG. 5 is a diagram showing the relationship between the thickness of printing paper and the distance between the print head and the platen.

In this diagram, line A shows the ideal relationship between the thickness of the printing paper and the distance between the print head and the platen. In the dot printer device of the present invention, the thickness of the print paper can be known, and based on this, the distance between the print head and the print paper, that is, the distance between the print head and the platen, can be determined by taking into account the restoration due to the elasticity of the print paper. The distance between the two can be adjusted appropriately so that the distance between the two lines approaches the ideal value of line A.

On the other hand, the lines showing the number of pulses represent the print head position adjustments made in the prior art apparatus.

It can be seen that in this case there is a large deviation from the ideal line A.

Note that the configuration in which the drive machine (t) and the drive mechanism have a tax adjustment function are not limited to the embodiments.

Further, the detection element is not limited to the example.

[Effects of the Invention] As explained above, according to the dot printer device of the present invention, the thickness of the printing paper is automatically measured, and based on this measurement result, printing is performed taking into account the elastic deformation of the printing paper. By appropriately adjusting the position of the print head relative to the paper, it is possible to secure a space between the print head and the print paper so that they do not get caught. Therefore, it is possible to perform good dot printing.

[Brief explanation of drawings]

1 to 3 show an embodiment of the present invention, FIGS. 1 and 2 are diagrams showing a dot printer device, FIG. 3 is a flowchart showing the operation of the same device, and FIG. 4 is a conventional device. FIG. 5 is a diagram showing the relationship between the thickness of printing paper and the distance between the print head and the platen. 2...Platen, 3...Carriage assembly, 6...
- Print head, 8... Pulse motor, 13... Detection element, 15... Controller, 16... Print paper. g-body 2 figure

Claims (1)

[Claims] In a dot printer device that prints on the print paper by bringing the print head into contact with the print paper loaded on the platen,
a moving body on which the print head is mounted; and a drive mechanism that moves the moving body forward in a direction approaching the platen and backward in a direction away from the platen using a moving force obtained by rotation of a pulse motor. a detection element that is provided at a position apart from the platen and detects when the movable body moving backward from the platen passes; and when the platen is loaded with print paper, the movable body moves backward from the print paper. The detection element is moved backward, and during this backward movement, the number of excitation pulses input to the pulse motor of the drive mechanism is counted, and this measured pulse number and the The number of excitation pulses input to the pulse motor of the drive mechanism is compared with the number of excitation pulses inputted to the pulse motor of the drive mechanism while the movable body moves backward from the platen to the detection element, and the difference is determined. Based on the result of this difference, the print is placed on the platen. A dot printer device characterized by comprising a controller for determining the thickness of paper.