JP2726069B2 - Image recording device - Google Patents

Description

The present invention relates to an image recording apparatus that drives a carriage using a motor.

[Conventional technology]

Conventionally, in an image recording apparatus in which the driving force of a motor is transmitted to a carriage equipped with a recording head via a belt or a wire and the recording head is reciprocally scanned, the change in the angular velocity of the motor until the carriage reaches a steady speed. In general, the angular velocity is controlled such that a constant angular velocity is obtained when the angular acceleration becomes zero by gradually decreasing the angular acceleration.

[Problems to be Solved by the Invention] However, in the conventional apparatus as described above, when the stopped carriage starts to move, a periodic vibration of the carriage in the traveling direction occurs, and the vibration is steadily accompanied by the vibration. Since it accelerates to speed, it has the following disadvantages.

Although the vibration of the carriage gradually attenuates, the vibration of the carriage cannot be fully attenuated even when the carriage drive motor reaches a steady angular velocity. Therefore, it takes a long time for the carriage to reach a steady speed and a long distance is required.

In order to attenuate the vibration of the carriage quickly, it is necessary to increase the sliding force between the carriage and the bearing portion or to apply the sliding force to the carriage by another sliding member to increase the resistance. Requires a high-torque carriage drive motor to increase
This is disadvantageous in terms of space and heat generation.

The waveform diagram in FIG. 7 shows the conventional disadvantages listed in the above section. As an example, the carriage is driven via a belt by a pulse motor of 3.6 mm per step and a pulley having a pitch circle diameter of 10 mm, and the 500 In the case of acceleration to a steady speed of × 0.1πmm / s, the vertical axis represents the driving frequency of the pulse motor and the speed of the carriage, the horizontal axis represents time, and the driving frequency of the pulse motor is represented by a broken-line curve. It is shown by.

As can be seen from FIG. 7, it can be easily understood that the vibration generated at the start of the movement of the carriage remains without being attenuated when the motor reaches the steady speed region.

Accordingly, it is an object of the present invention to quickly attenuate periodic vibrations of a steady-speed moving object such as a carriage without increasing the sliding force of the object without increasing the sliding force.
It is an object of the present invention to provide an image recording apparatus in which a stationary state becomes a steady speed in a short distance.

[Means for solving the problem]

In order to achieve the above object, the present invention is an image recording apparatus having a pulse motor for driving a carriage provided with a recording head for image recording, wherein a driving frequency of the pulse motor for driving and scanning the carriage is determined. A pulse oscillation circuit for generating a pulse signal; and a motor drive circuit for sequentially advancing each phase pattern of the pulse motor in accordance with the pulse signal generated from the pulse oscillation circuit, which is generated when the carriage starts moving from a stop. Due to the periodic vibration in the traveling direction, the acceleration of the carriage decreases from zero to negative, and at a timing until it increases again, the angular acceleration required to bring the pulse motor to a steady angular velocity is increased. The driving frequency of the pulse motor is determined by using the pulse oscillation circuit and the motor drive circuit. Characterized thereby pressurized.

[Action]

According to the present invention, according to the above configuration, the pulse motor is set to a steady state at the timing when the acceleration of the carriage decreases from zero to negative and then increases again due to the periodic vibration in the traveling direction generated when the carriage starts moving from the stop. The drive frequency of the pulse motor is increased by using a pulse oscillation circuit and a motor drive circuit so as to increase the angular acceleration required to achieve the angular velocity. Periodic vibrations can be damped quickly without increasing the sliding force in particular, allowing the carriage to reach a steady speed in a shorter time and a shorter distance.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a circuit configuration of an embodiment of the present invention. Reference numeral 10 denotes a pulse oscillation circuit that generates a pulse signal (f) for determining the drive frequency of the stepping motor 1 that drives and scans the carriage (moving object at a constant speed). This is a motor drive circuit that sequentially advances each phase pattern (A, B, and B signals).

Pulse oscillation circuit 10 has a table as shown in Table 1 below, the pulse width is sequentially outputted from the T _1, accelerated from T ₁ to T _9, then T ₉ and a pulse width of several outputs performs constant speed, then T ₁₀ accelerates again up to Tn, performs constant speed rotation thereafter Tn pulse width. In addition, as the above-mentioned carriage, a carriage of a liquid jet recording apparatus equipped with a recording head for recording characters and images by discharging droplets from a discharge element using thermal energy can be applied.

FIG. 2 shows waveforms of input / output signals of the motor drive circuit 11 of FIG.

FIG. 3 shows a main configuration of an image recording apparatus provided with the stepping motor 1 of FIG. In FIG. 3, reference numeral 2 denotes a carriage on which a recording head (not shown) is mounted, 3 denotes a pulley directly connected to a rotor shaft of a stepping motor (hereinafter referred to as a pulse motor) 1, and 4 denotes a driving force of the motor 1 via the pulley 3. A timing belt 5 to be transmitted to the carriage 2 is a guide rail for guiding the carriage 2.

4 shows the relationship between the time when the driving frequency is applied to the pulse motor 1 via the motor drive circuit 11 and the motor driving frequency by a broken line a. The relationship of the carriage speed of the driven carriage 2 is shown by a solid line b, and the carriage 2
The relationship between the acceleration and time is shown by a solid line c.

The pulse motor 1 is, for example, of 3.6 mm per step, and the carriage 2 is a pulley 3 having a pitch circle diameter of 10 mm.
Is driven along a guide rail 5 via a belt 4 and an image is recorded by a recording head (not shown) fixed to the carriage 2. At this time, the pulse motor 1
It accelerates to pps and the angular acceleration becomes almost zero.

At this time, the carriage 2 has a periodic vibration of 100 m with respect to the traveling direction generated when the carriage 2 starts moving from the stop.
At the time of s, an attempt is made to accelerate to 200 × 0.1πmm / s, but at the time of 100 ms, the speed of the carriage 2 is actually accelerated to about 320 × 0.1πmm / s due to the occurrence of vibration. Once the acceleration becomes zero, decelerate from here to 200 x 0.1
Attempts to move to πmm / s.

Therefore, at the moment of zero acceleration, the drive frequency of the pulse motor 1 is increased by using the pulse oscillation circuit 10 and the motor drive circuit 11 shown in FIG. 2 is prevented, and the difference between the speed of the carriage 2 and the peripheral speed of the pitch circle diameter of the pulley 3 rotated by the pulse motor 1 is reduced. Therefore, the vibration of the carriage 2 becomes small, and the vibration can be attenuated in a short time.
In this example, the angular acceleration of the motor 1 immediately before increasing the angular acceleration of the motor 1 is temporarily zero. Further, the above-mentioned change in acceleration can be easily obtained in advance by an experiment using a known acceleration detection sensor, and based on this experimental value, the change in the motor drive frequency a is set as shown by the broken line in FIG. Like that.

FIG. 5 shows another embodiment of the present invention. In this figure, the relationship between the motor drive frequency applied to the pulse motor 1 and time is indicated by a broken line a, as in the case of FIG. 4 of the first embodiment of the present invention, and the relationship between the carriage speed of the carriage 2 and time is shown. Is indicated by a solid line b, and the relationship between the acceleration of the carriage 2 and time is indicated by a solid line c. In the present embodiment, the acceleration of the driving frequency of the pulse motor 1 is reduced immediately before the acceleration starts decreasing again from zero to negative because of the speed fluctuation generated by the periodic vibration of the carriage 2 in the traveling direction. It has increased. Until this time, carriage 2
Since the acceleration due to the vibration of the pulse motor 1 is decreasing, by increasing the angular velocity of the pulse motor 1 at this time, the carriage 2 is given a positive acceleration, the negative acceleration of the carriage 2 is reduced, and the vibration is rapidly damped. Become.

FIG. 6 shows still another embodiment of the present invention. In this case, similarly to FIG. 4 of the above-described first embodiment of the present invention, the relationship between the motor drive frequency applied to the pulse motor 1 and time is shown. The relationship between the speed and the time of the carriage 2 is shown by a solid line b.
The relationship between the acceleration of the carriage 2 and time is indicated by a solid line c.

In the present example, the acceleration of the driving frequency of the pulse motor 1 increases when the acceleration is about to decrease from zero to negative for the first time due to periodic vibration in the traveling direction of the carriage 2. In the above-described first embodiment, the drive frequency of the pulse motor 1 is accelerated at the second time when the acceleration decreases from zero to negative due to vibration.
The same effect can be obtained by accelerating the drive frequency when the acceleration is about to decrease from zero to negative for the first time.

Naturally, the same effect can be obtained at other times when the acceleration tends to decrease from zero to negative due to vibration. In each of the above-described embodiments, the pulse frequency is taken as an example to control the angular velocity by changing the drive frequency.However, in the case of another motor, for example, a DC motor, depending on the applied voltage, or in the case of an AC motor, It goes without saying that the same effect can be obtained even if the angular velocity of the motor is controlled by the applied power supply frequency.

〔The invention's effect〕

As described above, according to the present invention, at the timing when the acceleration of the carriage decreases from zero to negative and increases again due to the periodic vibration in the traveling direction generated when the carriage starts moving from the stop, The drive frequency of the pulse motor is increased by using the pulse oscillation circuit and the motor drive circuit to increase the angular acceleration required to bring the pulse motor to a steady angular velocity. In this case, the periodic vibration in the traveling direction is rapidly attenuated without increasing the sliding force, so that the carriage can be brought to a steady speed in a shorter time and a shorter distance.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a circuit configuration of an embodiment of the present invention, FIG. 2 is a timing chart showing input / output signal timings of the motor drive circuit in FIG. 1, and FIG. 3 is an embodiment of the present invention in FIG. FIG. 4 is a perspective view showing a main part configuration of an example image recording apparatus, FIG. 4 is a waveform diagram showing a relationship between a driving frequency of a pulse motor, a speed of a carriage, and an acceleration of a carriage in one embodiment of the present invention; FIG. 6 is a waveform diagram showing the relationship between the driving frequency of the pulse motor, the speed of the carriage and the acceleration of the carriage in another embodiment of the present invention, and FIG. 7 is the driving frequency of the pulse motor and the speed of the carriage in the conventional example. FIG. 6 is a waveform diagram showing a relationship between the acceleration and the carriage acceleration. 1 ... motor, 2 ... carriage, 3 ... pulley, 4 ... timing belt, 5 ... guide rail, 10 ... pulse oscillation circuit, 11 ... motor drive circuit.

Claims (1)

(57) [Claims] An image recording apparatus having a pulse motor for driving a carriage provided with a recording head for image recording, wherein a pulse for generating a pulse signal for determining a driving frequency of the pulse motor for driving and scanning the carriage is provided. An oscillation circuit, and a motor drive circuit for sequentially advancing each phase pattern of the pulse motor in accordance with a pulse signal generated from the pulse oscillation circuit, wherein the carriage periodically moves in a traveling direction generated when the carriage starts moving from a stop. The pulse oscillation circuit and the motor so as to increase the angular acceleration required to bring the pulse motor to a steady angular velocity at a timing when the acceleration of the carriage decreases from zero to a negative value and increases again. The drive frequency of the pulse motor is increased by using a drive circuit. Image recording apparatus for.