JPH0441254A - Impact dot printer - Google Patents

Abstract

PURPOSE:To print favorably for a long time without exceeding and receding printing forces by controlling a driving energy of printing wire independently in accordance with a detected value of a detecting circuit for detecting output signals of a pressure sensor. CONSTITUTION:When a printing force is to be adjusted, a print head 8 is moved to a position at the left end so as to strike a pressure sensor 13 in accordance with a print command through an ink ribbon 12. A striking surface 14 is adjusted to be at a position on the same plane as a striking surface of a platen 11, so that a printing force equivalent to a printing force at striking the platen 11 can be detected constantly even if a platen gap is changed. It is determined whether or not an output value of the pressure sensor 13 is within a predetermined allowable range. When the value is outside the allowable range, a driving energy is reset dependent on its exceeding and receding values so as to strike the pressure sensor again. This routine is repeated, and when the output value of the pressure sensor 13 enters the allowable range, a set data at that time is rewritten in a memory circuit and the routine proceeds to a next printing wire. Such a setting is done for all printing wires and an adjustment of the printing force is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure and control method of an impact dot printer.

[Prior Art] Impact dot printers print characters and symbols composed of dot matrices by selectively protruding multiple printing wires, but in order to obtain good printing quality, it is necessary to compensate for variations in the printing power of each printing wire. It is necessary to keep it as small as possible.

However, in order to reduce variations in printing power, it is necessary to extremely precisely control the precision of each individual component and the assembly precision, which has been a factor in increasing the cost of the print head.

Further, even if the variation in printing force is initially small, the frequency of use of each printing wire is different, and as a result of long-term use, the variation gradually increases depending on the state of wear of each part. Furthermore, there are many factors that affect printing power, such as ambient temperature, platen gap, and adhesion of paper powder, and printing power constantly fluctuates.

In order to reduce the influence of these variations in printing power,
Conventionally, drive energy has been set so that sufficient print density is achieved at the lower limit of printing force variation.

[Problems to be Solved by the Invention] However, when the drive energy is set in this way, the printing force may become excessive, leading to problems such as deterioration of the life of the ink ribbon and print head, increase in noise, and damage to the printing paper. Occur. In addition, the overall driving energy is larger,
This results in increased heat generation and reduced throughput.

The present invention is intended to solve these problems, and its purpose is to always supply appropriate driving energy to the printing force that fluctuates due to many factors, and to prevent insufficient or insufficient printing force.
To provide a highly reliable impact dot printer that is free from excessive printing and provides good printing over a long period of time.

[Means for Solving the Problems] Accordingly, the impact dot printer of the present invention includes a print head having a plurality of print wires, a carriage for moving the print head from side to side, and a position within the movable range of the print head and outside the print area. a pressure-sensitive sensor provided in the pressure-sensitive sensor, a print head drive circuit that sequentially hits each printing wire on the pressure-sensitive sensor, a detection circuit that detects the output signal of the pressure-sensitive sensor, and a drive energy for each printing wire that is independently controlled. and a drive energy control circuit for controlling, according to the detection value of the detection circuit,
It is characterized by independently controlling the drive energy of each printing wire.

Further, the present invention is characterized in that closed feedback control is performed to increase or decrease the drive energy so that the detection value of the detection circuit falls within a preset reference range.

Further, each printing wire is characterized by having a memory circuit that independently stores drive energy setting data, and a backup circuit that backs up the data in the memory circuit.

Further, the present invention is characterized in that it includes a storage circuit that stores in advance the optimum drive energy according to the detection value of the detection circuit.

Further, it is characterized in that the striking surface of the pressure-sensitive sensor is provided on the same plane as the striking surface of the normal printing area.

[Examples] Hereinafter, details of the present invention will be described based on illustrated examples.

FIG. 1 is a block diagram showing the overall configuration of an embodiment of the present invention. The signal generated by the pressure sensor 1 is converted by the detection circuit 2 into an electrical signal of a level that can be handled by the comparison/judgment circuit 3, and compared with the reference signal generated by the reference signal generation circuit 4. Based on the result, the drive energy control circuit 5 sets the drive energy and outputs a command to the print head drive circuit 6. The setting data of the drive energy control circuit 5 can be read from and written to the memory circuit 7.

FIG. 2 is a schematic diagram of an impact dot printer showing an embodiment of the present invention, in which the print head 8 is connected to a carriage guide shaft 9.
It is fixed to a carriage 10 that moves while being guided by. Normally, the printing head 8 moves within a printing area of the platen 11 and prints on printing paper (not shown) inserted between the platen 11 and the ink bottle 12.

The pressure-sensitive sensor 13, which is disposed within the movable range of the print head 8 and outside the printing area, is an element such as a piezo element that generates an electromotive force according to pressure, and as shown in FIG. When it collides with the striking surface of the pressure sensor, it generates an electromotive force proportional to the striking force.

When adjusting the print force, the print head 8 moves to the position shown by the broken line and hits the pressure sensor 13 via the ink ribbon 12 in accordance with the print command. The striking surface 14 is the platen 11
Even if the platen gap is changed, the same printing force as when hitting the platen 11 can always be detected.

FIG. 4 is a flowchart showing a control method for printing force adjustment.

The print power adjustment command is issued when the power is turned on or at any time by manual operation. Upon receiving this command, the print head moves to the impact position of the pressure-sensitive sensor described above. Next, the drive energy is set according to the data stored in the memory circuit (the drive conditions stored at the time of the previous printing force adjustment), and striking is performed. Next, it is determined whether the output value of the pressure sensor is within a preset allowable range, and if it is outside the allowable range, the drive energy is reset according to the excessive or small value, and the Back to hitting the sensor.

This routine is repeated, and when the output value of the pressure sensor falls within the allowable range, the setting data at that time is rewritten in the memory circuit, and the process proceeds to setting the next printing wire. Perform this setting for all printing wires and complete the printing force adjustment. The driving condition data written in the memory circuit is backed up by a battery and is saved even after the power is turned off.

FIG. 5 is a flowchart showing another embodiment of the printing force adjustment method.

First, a blow is applied to the pressure sensor under standard driving conditions, and the detected value is digitized by an A/D converter. Optimum driving conditions corresponding to the detection data of the pressure sensor are written in advance in the memory circuit, and this data is read, driving energy is set, and the process proceeds to setting the next printing wire.

In the case of this adjustment method, since closed feedback is not provided, the printing force setting accuracy is lower than that of the above-mentioned method, but the adjustment time is significantly shortened.

FIG. 6 is a graph showing the printing power of a conventional impact dot printer with constant drive energy, and FIG. 7 is a graph showing the printing power when the drive energy is corrected according to the above-described embodiment. In this example, the driving energy is adjusted by changing the energization time. When the energization time is constant, for a printing wire whose printing force exceeds the permissible range, increase or decrease the energization time by several tens of microseconds to increase or decrease the energization time by several tens of microseconds.
~5.5N.

[Effects of the Invention] As described above, according to the present invention, printing force can be directly detected,
Because each printing wire is adjusted independently, it is not affected by factors that cause printing force to fluctuate, such as initial variations in the print head, ambient temperature, platen gap, adhesion of paper dust, drive unit wear, and ink ribbon thickness. The drive energy is always set to the optimum value for the printer, and a constant printing force with no excess or deficiency can be obtained. As a result, we have solved various problems related to the basic performance of impact dot printers, such as problems such as heat generation, noise, paper damage, and deterioration of ink ribbon and print head life when the drive energy is too high, and insufficient print density when the drive energy is too low. Can be solved effectively.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a schematic diagram of an impact driver 1-printer showing an embodiment of the invention, and Fig. 3 shows the output signal of the pressure sensor and the operation of the printing wire. 4 and 5 are flowcharts showing the operation of the embodiment of the present invention, and FIGS. 6 and 7 are graphs showing the printing power of impact dot printers according to the prior art and the embodiment of the present invention, respectively. . 1.1 2 ・ 3 ・ ・ 4 ・ 5 ・ 6 ・ 7 ・ 10 ・ 11 ・ 12 ・ 15 ・ ... Pressure sensor detection circuit Comparison/judgment circuit Reference signal generation circuit Drive energy control circuit Print head drive circuit Storage circuit Print head, carriage, platen, ink ribbon, backup circuit and above Applicant: Seiko Epson Co., Ltd. Representative Patent attorney: Kizobe Suzuki @1 person Figure 4 Figure 5

Claims (5)

[Claims] (1) A print head having a plurality of print wires, a carriage that moves the print head left and right, a pressure sensor installed within the movable range of the print head and outside the printing area, and a pressure sensor installed on each of the pressure sensors. A print head drive circuit that sequentially hits the print wires, a detection circuit that detects the output signal of the pressure-sensitive sensor, and a drive energy control circuit that independently controls the drive energy of each print wire. An impact dot printer characterized by independently controlling the drive energy of each printing wire according to detected values. (2) The impact dot printer according to claim 1, wherein closed feedback control is performed to increase or decrease drive energy so that the detection value of the detection circuit falls within a preset reference range. (3) The impact dot printer according to claim 1, further comprising a memory circuit that independently stores drive energy setting data for each printing wire, and a backup circuit that backs up data in the memory circuit. (4) The impact dot printer according to claim 1, further comprising a memory circuit that stores in advance the optimum drive energy according to the detection value of the detection circuit. (5) The impact dot printer according to claim 1, wherein the impact surface of the pressure sensor is provided on the same plane as the impact surface of the normal printing area.