JPH0615879A - Printing device - Google Patents

Abstract

PURPOSE:To ensure that print quality is stable, the ease of operating a printing device is better and productivity is enhanced by providing a means for controlling the speed of a motor which corresponds to a potential detected by a means for detecting a head voltage, and changing the transport speed of a dot head in response to an applied voltage. CONSTITUTION:The actual value of wire flying time variation of a dot head 2 due to a change in power supply voltage is determined, and the variation characteristics of (power supply voltage-wire flying time) is calculated. Further, drive parameters of a transport motor 1 for each potential are decided in accordance with the variation characteristics, and the decided parameters are previously entered in a storage circuit 7 in terms of software. That is, a power supply voltage and the rotating speed of a motor 1 are set at the center value of actual use conditions. In addition, when adjusting a printing position, the voltage is detected by a head voltage detection circuit 6, if a power supply voltage changes after the adjustment of a printing position, and the detected information is transmitted to a motor rotating speed control circuit 4. Further, the circuit 4 determines the rotating speed of the motor 1 in accordance with the potential detected by the circuit 6 based on data entered in the circuit 7, and the circuit 4 adjusts drive parameters for the motor 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus which prints while carrying a dot head bidirectionally and repeats the operation a plurality of times to form a printing apparatus.

[0002]

2. Description of the Related Art Conventionally, in the printing apparatus as described above, when printing is performed bidirectionally at the position A as shown in FIG. 3, the wire of the dot head reaches the printing surface from the start of energization of the dot head. Since the distance L from the energization start position to the dot head to the position A to be printed is determined by the flight time up to and the transport speed of the dot head, when the dot head is transported in each of the directions A and B, The generation positions of the energization timing pulses Tn and Tn 'to the dot head are adjusted to be a distance of 2L.

However, the power source for the dot head and the motor for driving the dot head is generally shared, and if the voltage of the power source changes after the above-mentioned print position adjustment, the print position is displaced from the A position. I will end up.

This will be described with reference to FIG. 6, which shows both the relationship of <power supply voltage-dot head transport speed> change characteristics and <power supply voltage-wire flight time> change characteristics. After performing the above-described print position adjustment at the center value (Typ. Value) of the range, the change in the flight time of the wire shows the characteristic of a with respect to the voltage change of the power supply,
The change in the carrying speed of the dot head shows the characteristic of b when a DC motor having no rotation speed control means is used as the carrying driving motor, while the block diagram of FIG.
When a DC motor or pulse motor having a rotation speed control means configured as described above is used to control the rotation speed of the motor to a constant value, the wire has a characteristic of c. This is because a deviation occurs in the rate of change between the flight time and the transport speed of the dot head.

Since the flight time of the wire is governed by the acceleration component, the square value of the rate of change becomes the change characteristic of the flight time of the wire with respect to the rate of change of the power supply voltage. On the other hand, the transport speed of the dot head in the conventional example shows a characteristic that the rate of change is substantially equal to the power supply voltage when speed control of the transport drive motor is not performed, and the transport speed of the transport drive motor is This is because when the rotation speed is controlled to be constant, it exhibits a characteristic that does not change.

Incidentally, since the change characteristics of the dot head carrying speed and the carrying driving motor rotational speed inevitably coincide with each other in the change of the power supply voltage, the speeds mentioned above are hereinafter referred to as the same meanings. It will be expressed as a thing.

Here, a DC having no rotation speed control means
A case where a motor is used will be described with reference to FIG. 4. When the power supply voltage is increased after the printing position adjustment described above, the flight time of the wire becomes relatively slow with respect to the transport speed of the dot head. The distance from the energization of the dot head to the printing point with the pulses Tn and Tn ′ is L + α, and the printing position shift in both directions is 2α. Further, when the voltage of the power supply is lowered, the flight time of the wire becomes relatively fast with respect to the transport speed of the dot head, so that the pulse Tn and Tn ′ from energization of the dot head to the printing point The distance is L-β, and the print position shift from both directions is 2β.

On the other hand, when a DC motor or a pulse motor having a rotation speed control means is used to control the rotation speed of the motor to a constant value with respect to a change in power supply voltage, an example is shown in FIG.
In the explanation, when the power supply voltage is increased after the printing position adjustment described above, the flight time of the wire is relatively fast with respect to the transport speed of the dot head.
The distance from energizing the dot head to the printing point at Ln and Tn 'is L-α', and the printing position shift from both directions is 2
α '. Further, when the power supply voltage is lowered, the flight time of the wire becomes relatively slow with respect to the transport speed of the dot head, and therefore, from the energization of the dot head with the pulses Tn and Tn ′ to the printing point. The distance is L + β ', and the print position shift from both directions is 2β'.

As described above, in the conventional printing apparatus, the printing position shift is unavoidable for the above reasons regardless of whether the rotation speed control of the dot head transport drive motor is performed or not. Therefore, the print position adjustment described above is performed at the center value in the actual allowable voltage range of the printing device, and the print position deviation amount is evenly distributed to minimize the absolute amount. After allowing or allowing each printing apparatus to be combined with a dedicated power source, the above-described print position adjustment is performed, and the voltage change after the adjustment is avoided to prevent the print position deviation.

As described above, in order to maintain the best print quality without print position deviation, there is no choice but to set the power supply voltage to the same voltage as when the print position is adjusted, and when evaluating and inspecting the printing apparatus alone. , Voltage adjustment or print position adjustment is required for each power source used, and even for the dedicated power source of each printing device,
Since it is necessary to adjust the printing position again, it is troublesome and there is a problem in mass productivity.

Further, when replacing the printing apparatus during actual use, it is necessary to adjust the printing position again or adjust the voltage again, which is inconvenient.

[0012]

SUMMARY OF THE INVENTION Therefore, the present invention is intended to solve the above-mentioned problems, and its purpose is to stabilize the print quality, improve the usability of the printing apparatus, and improve the mass productivity by improving the function. Is to raise.

[0013]

In order to solve the above-mentioned problems, a printing apparatus according to the present invention is a printing apparatus which prints while carrying a dot head in both directions and repeats the operation a plurality of times. In the above, a motor for carrying the dot head, a head voltage detecting means for detecting a voltage applied to the dot head, and a motor speed control means for controlling the rotation speed of the motor in accordance with the potential detected by the head voltage detecting means. And the dot head transport speed is
It is characterized in that it changes according to the voltage applied to the dot head. Further, the motor speed control means is characterized by having a storage means for associating the voltage applied to the dot head with the rotation speed of the motor.

[0014]

With the above-described means, the rotation speed of the dot head transport drive motor is varied so that the rate of change between the dot head transport speed and the dot head wire flight time is the same with respect to changes in the power supply voltage. It can be controlled.

[0015]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing drive control means of a transport driving motor 1 for a dot head 2. The circuit configuration of the drive control means shown in the block diagram 1 according to an embodiment of the present invention is shown in the block diagram 2. A head voltage detection circuit 6 and a storage circuit 7 are added to the circuit configuration of the conventional drive control means. In a block diagram 1 showing an embodiment of the present invention,
A case where a pulse motor is used as the transport driving motor 1 will be described.

By grasping the actual value of the change in the flight time of the wire of the dot head 2 due to the change of the power supply voltage, the change characteristic a of <voltage of power supply-time of flight of wire> shown in FIG. At the same time, the drive condition of the transport drive motor 1 is determined for each potential, and is input to the storage circuit 7 in advance by software. For example, the power supply voltage and the rotation speed of the conveyance driving motor 1 are set to the center values of the actual use conditions,
When the above-mentioned print position adjustment is performed, when the power supply voltage changes after the print position adjustment, the voltage is detected by the head voltage detection circuit 6, and the information is transmitted to the motor rotation speed control circuit 4.

Since the rotation speed of the transport drive motor 1 can be controlled by the drive pulse frequency on the drive control circuit side, the motor rotation speed control circuit 4 detects the head voltage detection circuit 6 from the data input to the memory circuit 7. The rotation speed of the motor 1 is determined according to the applied potential, and the motor rotation speed control circuit 4 adjusts the drive condition (drive pulse frequency) of the conveyance drive motor 1 to determine the rotation speed of the conveyance drive motor 1. Is controlled according to the change characteristics of the flight time of the wire.

Next, referring to the block diagram 1 of the present invention, a case where a DC motor is used as the transport driving motor 1 will be described.

Unlike the above-mentioned use of the pulse motor, the actual value of the change in the flight time of the wire due to the change in the power supply voltage is grasped, and the power supply voltage-the flight time of the wire is shown in FIG.
Change characteristic a is determined and stored in advance in hardware by a combination of circuit elements such as resistors and capacitors configured in the speed control circuit 4 so that the driving condition of the conveyance driving motor 1 matches the characteristic a. It is configured as the circuit 7. For example, when the power supply voltage and the rotation speed of the conveyance driving motor 1 are set to the center values of the actual use conditions and the above-described print position adjustment is performed, if the power supply voltage changes after the print position adjustment, the voltage is The voltage is detected by the voltage detection circuit 6, and the information is transmitted to the motor rotation speed control circuit 4.

The rotation speed of the transport drive motor is detected by a motor speed detection circuit 5 such as a tacho generator or an encoder, and the information is transmitted to the motor rotation speed control circuit 4. In the motor rotation speed control circuit 4, the storage circuit 7
Based on the data input to the head voltage detection circuit 6
The rotation speed of the transport drive motor 1 is determined in accordance with the potential detected by and the drive condition (current value or energization time) of the transport drive motor 1 is adjusted by the motor rotation speed control circuit 4. While controlling the information transmitted from the speed detection circuit 5, the rotation speed of the transport driving motor 1 is controlled in accordance with the change characteristic of the flight time of the wire. By performing the above-described motor speed control, it is possible to variably control the rotation speed of the transport drive motor 1 in accordance with the change characteristics of the flight time of the wire with respect to the change in the voltage applied to the dot head 2. Becomes

[0021]

According to the printing apparatus of the present invention, the motor for moving the dot head, the head voltage detecting means for detecting the voltage applied to the dot head, and the motor corresponding to the potential detected by the head voltage detecting means. And a motor speed control means for controlling the rotation speed, wherein the carrying speed of the dot head changes in accordance with the applied voltage of the dot head, and the motor speed control means has the applied voltage of the dot head. And a rotation speed of the motor are associated with each other. According to the present invention, the rotation of the transport drive motor is adjusted in accordance with the change characteristic of the flight time of the wire due to the change in the voltage applied to the dot head. Since variable control that changes the speed is possible, the printing position deviation due to the voltage change after the printing position adjustment described above does not occur, and the printing quality of the printing device is reduced. It can be.

Further, since the voltage adjustment for each power source or the reprinting position adjustment is unnecessary, the usability of the printing apparatus is improved, and the workability at the time of evaluation and inspection is reduced, thereby improving the mass productivity. Is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of a motor drive control circuit according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a motor drive control circuit configuration in a conventional example.

FIG. 3 is an explanatory diagram of a printing position adjusting method in a conventional example.

FIG. 4 is an explanatory diagram of a print position shift occurring when a motor rotation speed is not controlled in a conventional example.

FIG. 5 is an explanatory diagram of occurrence of printing position deviation during constant motor rotation speed control in a conventional example.

FIG. 6 is a graph showing the change characteristics of the dot head transport speed and the wire flight time with respect to changes in the power supply voltage.

[Explanation of symbols]

 1 Motor for Transport Drive 2 Dot Head 3 Motor Drive Circuit 4 Motor Rotation Speed Control Circuit 5 Motor Rotation Speed Detection Circuit 6 Head Voltage Detection Circuit 7 Storage Circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location 9211-2C 114C

Claims (2)

[Claims] 1. A printing apparatus configured to print by carrying a dot head bidirectionally while carrying out printing and repeating the operation a plurality of times, and a motor for carrying the dot head, and an application to the dot head. Head voltage detection means for detecting a voltage, and a motor speed control means for controlling the rotation speed of the motor corresponding to the potential detected by the head voltage detection means, the transport speed of the dot head, the A printing device characterized in that it changes according to the applied voltage of the dot head. 2. The printing apparatus according to claim 1, wherein the motor speed control unit has a storage unit that associates a voltage applied to the dot head with a rotation speed of the motor.