JP2021020351A - Printing device - Google Patents

Abstract

To reduce problems of electromagnetic wave leakage.SOLUTION: A printer includes transceiving antennae arranged on both sides of a working unit of a printer vertically in the operation direction thereof for wireless power feeding to the working unit of the printer.SELECTED DRAWING: Figure 6

Description

The present invention relates to a power transmission method in a printing apparatus represented by an inkjet method, and more particularly to power transmission to a moving portion of a print head having an ink ejection function.

Conventionally, electric power and signal transmission to the print head, which is a moving part, have been realized by wired wiring. As the transmission cable, means such as electric wires, FFC, and FPC have been used. These means are inexpensive and have the advantage of being simple in configuration.

On the other hand, there is a technology to replace the above wiring with a wireless communication means. Wireless power transmission has been realized by the electromagnetic induction method for a long time. By bringing the center of the coil of the device on the transmitting side and the device on the receiving side close to each other, an induced current is generated from the electromagnetic wave on the transmitting side by the change in the electromagnetic wave of the coil on the receiving side for communication. It has been put into practical use from early on as a power supply method for electrical equipment used in water-wet environments such as electric razors and toothbrushes.

In recent years, this method has tended to be used more and more, such as for supplying power to mobile phone chargers and IC cards. While this method has many useful advantages, it has the disadvantage that efficient power transmission cannot be performed unless the positions of the transmitting side and the receiving side are close and stable. Considering this case, it was difficult to draw a practical configuration in a system in which the distance between the transmitting side and the receiving side is large and the distance changes.

Under such circumstances, an electromagnetic resonance type power transmission method using a resonance phenomenon has been proposed (see Patent Document 1). This method is a method capable of selectively transmitting between devices having a specific resonance frequency. In addition, it is possible to transmit electricity between devices that are farther apart than the electromagnetic induction method. The standard of the transmission distance that can be achieved is given by the product of k (coupling coefficient) and Q (wL / R). Even if the transmission distance is lengthened and k (coupling coefficient) is reduced, power can be transmitted by using an antenna having a large Q value. That is, power can be transmitted if the product of the resonance frequency and the mutual inductance is sufficiently larger than the resistance value. There is also a report that the electromagnetic resonance method can achieve a transmission efficiency of 80% or more even if the distance between the devices is 15 cm in a frequency band of several tens of MHz.

Japanese Patent No. 5927789

In the above-mentioned prior case, it is proposed to propose electric power transmission to a moving part such as a head of an inkjet printer by a wireless transmission means. The electromagnetic resonance method is a method that utilizes a resonance phenomenon, and even if the distance between the devices changes, there is no dramatic change in efficiency as compared with the electromagnetic induction method or the like. However, it is self-evident that the arrangement of the antennas on the transmitting side and the receiving side has a constant distance between the antennas, and it is advantageous in terms of power supply that the fluctuation is small. However, if such a configuration is adopted in the head moving part of the inkjet printer, the antenna on the transmitting side becomes an offensive toward the front of the paper ejection port, and depending on the position of the head unit on the receiving side, the antenna on the receiving side may move outward from the paper ejection port. It is inevitable that the structure will allow electromagnetic waves to leak.

The present invention proposes a configuration that reduces the problem of leakage of electromagnetic waves that such a structure has.

In order to solve the above problems, the printing apparatus according to the present invention
It relates to a configuration for reducing leakage of radio waves to the outside in view of practicality in power transmission to a moving part using an electromagnetic resonance method. Place the carriage perpendicular to the operating direction. By doing so, the electromagnetic field leaking from the paper ejection port can be significantly reduced. The resonance frequency moves and the Q value changes, but this is compensated for by arranging power transmission antennas on both sides. Interference can be avoided by separating the resonance frequencies of the antennas arranged on both sides of the carriage.

According to the printing apparatus according to the present invention, since the leakage electromagnetic field is reduced, it becomes easier to use for commercialization.

The figure which shows the electric composition of this proposal The figure which shows the mechanical structure of this proposal The figure which shows the structure of the electric power transmission to a conventional head part Diagram showing power transmission efficiency in the conventional configuration Diagram showing the distance and efficiency between conventional antennas The figure which shows the structure of electric power transmission to the head part of this proposal The figure which shows the power transmission efficiency in the configuration of this proposal

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

In this embodiment, a serial type inkjet printer is assumed. However, the same can be performed even with a multifunctional serial multifunctional inkjet printer equipped with a scanner.

The electrical configuration of the printing apparatus of the present invention is shown in FIG.

Power is supplied via the AC cable 1. The AC power is converted into DC power by the power supply unit 2. The DC power is sent to the power supply IC 6 through the DC power supply line 3 and converted into a DC voltage 7. Similarly, the voltage of the second system converted into DC power by the power supply unit 2 is transmitted to drive the printhead through the power supply line 4.

Further, the DC power source converted by the power supply IC 6 supplies power to the control unit 12 by the DC power supply line 7. The power supply IC 6 is controlled by the DCDC control line 8. The control unit 12 includes an ASIC 13 having a built-in microcomputer, a ROM 15 for storing a program, a RAM 14 as a work area, and an EEPROM 16 for storing settings and the like.

Further, the power supply IC 6 is controlled by the control unit 12 and drives a plurality of motors 9 to 11. These motors are a motor 9 for driving a carrier unit, a motor 10 for transporting paper, and a motor 11 for feeding paper. The printing device exchanges data with the control unit 12 with an external computer or network via the IF unit 17. The user interface is composed of an LCD 24, a touch panel 20, a key 26, and an LED 25, and presents information to the user, and accepts key operations and operations from the user from the touch panel. The touch panel 20 is controlled by the touch panel control IC 19. There are various methods, but a method of detecting capacitance and a method of detecting resistance value can be considered.

The touch panel control IC 19 is controlled by communicating with the control unit 12. The control signal 21 is composed of high-speed serial communication. The LCD 24, the key 26 and the LED 25 are controlled by the panel control IC 23. The panel control IC 23 and the LCD 24 communicate with each other by high-speed parallel communication 28. Further, the panel control IC 23 and the control unit 12 communicate with each other by high-speed serial communication 27.

A plurality of sensors 31, 32, 33, 34, 35, 36 are used for print control. First, the paper tip rear end detection sensor 31 is a sensor that detects the timing when the paper passes the position of the sensor, and it is possible to know the timing when the front end of the paper arrives at this position and the timing when the rear end is separated. It is composed of a photo interrupter in combination with a flag which is a mechanical member. Next, the paper transport position detection sensor 32 is composed of a linear encoder, and detects the position, the rotation direction, and the speed by reading the scale printed on the circular film with the sensor.

Next, the wiper position detection sensor 33 initializes the position of the wiper, which is a function of maintaining the state of the print head by wiping off the ink adhering to the surface of the print head. The wiper is controlled from the position of this sensor and the position information of the paper transport sensor. It is composed of a combination of a mechanical member and a photo interrupter.

Next, the paper separation mechanism position detection sensor 34 is a sensor that detects the inclination angle of the mechanical member at the time of paper feeding, and is composed of a mechanical switch. By using this mechanism, it is possible to feed multiple types of media. Next, the paper feed position detection sensor 35 is composed of a linear encoder and a rotary scale like the paper transport position detection sensor. As a result, the position, rotation method, and speed of the paper feed control are detected. Next, regarding the access cover sensor 36, the drive of the carrier unit, which is a movable part, is stopped by detecting the sensor with a cover on the front of the device that is opened to remove the ink tank and paper. This is to prevent the user from being caught in the carrier unit.

The carriage unit 52 is equipped with a print head 48, an ink tank 51, and a carriage position detection sensor 53. The print head 48 includes a heater board 49 of the head and a sensor 50 that detects the temperature of the head. The ink tank 51 is independent for each color, and is composed of four colors (Y, M, C, Bk) in this embodiment. This unit reciprocates by driving and transmitting the rotation of the carrier motor with a belt. At that time, ink is ejected from the print head 48 to form an image. The heater board 49 of the head is a device made by a semiconductor process, and is powered by the DC power supply 4 sent from the power supply unit 2 based on the power transmitted by the wireless power transmission means.

As the power transmission means to the head, the transmission side is composed of the head power supply control IC 39 in the control unit 12, the head power control unit 40, and the transmission antennas 41 and 42 arranged on both sides in the direction perpendicular to the operation direction of the carriage. To. The receiving side is composed of receiving antennas 45 and 46 and a head power control unit 47 arranged on both sides in a direction perpendicular to the operating direction of the carriage on the carriage unit 52. The head power supply control IC 39 has a function of controlling ON / OFF of power supply to the head.

The head power transmission control unit 40 changes the power input by DC to AC in order to transmit power wirelessly. The AC frequency at that time is set to a resonance frequency having high power transmission efficiency. Further, the control unit also changes the control by aligning or changing the phase of the AC power supplied to the antennas 45 and 46 arranged on both sides of the carriage. The impedance and frequency of the transmitting antenna are designed so that the transmission efficiency is improved. In this embodiment, it is assumed that transmission is performed at the same frequency, but the leakage flux can be further reduced by reversing the phase.

The receiving antennas 45 and 46 have the same frequency characteristics as the opposing transmitting antennas 41 and 42, and can selectively receive power by utilizing the resonance phenomenon. The head power transmission control unit 47 converts the power input by AC into DC and distributes the power to the heater board of the head unit 48, the ink tank 51, and the carriage position detection sensor 53. Since the voltage that drives the head unit and the voltage that drives the circuits and sensors in the ink tank are different, they are converted into multiple voltages and supplied. In addition, the headquarters lock is used to shut off the power when an error occurs in the carriage unit. With the above configuration, electrical transmission is performed into the carriage unit.

On the other hand, in this embodiment, it is assumed that the data is transmitted through the FFC 38. This data line includes print data on the print head 48, communication data with the ink tank 51, a detection signal of the sensor 50 for measuring the temperature of the head unit 48, and a detection signal of the sensor 53 for detecting the position of the carriage unit. .. Ideally, data transmission should also be wireless, but wireless communication using radio waves may cause problems with sensor signals that require high-speed data transfer and sequentiality. Optical communication and other means can be considered, but in this embodiment, wiring using FFC is assumed.

Next, FIG. 2 shows the mechanical configuration of the present proposal. This figure shows the vicinity of the carriage moving part of the printer unit.

Prior to the explanation of wireless power supply, the assumed mechanical configuration will be described in advance.

First, the paper is fed from the cassette arranged at the lower part of this figure by the paper transport roller 60. This roller is driven by the paper transport motor 58, and is controlled by reading the paper transport encoder scale 59. The carriage unit 57 is composed of a print head 61 and an ink tank 62, and it is assumed that the ink tanks are independent of each color. Specifically, the four color tanks C, M, Y, and Bk are loaded independently. The carriage unit 57 is driven by a carriage motor 63. The motor 63 and the carriage unit 57 are connected by a belt 65, and the rotation of the motor is transmitted to the drive. The position of the carriage is detected by the encoder sensor loaded on the carriage unit reading the encoder scale 64. As an operation, an image is formed by operating a carriage unit on a paper surface driven by a one-line paper separation motor and ejecting ink from a print head 61 at that time.

Next, FIGS. 3 to 5 show a method of wirelessly transmitting electric power to the carriage portion of the conventional method.

A feature of conventional wireless power transfer is that the transmitting side antenna 67 and the receiving side antenna 68 are arranged so that the distance becomes constant during carriage scanning. As shown in FIG. 3, the carriage unit moves left and right in the carriage scanning area 70 to perform a printing operation. At that time, the distance between the transmitting antenna 67 and the receiving antenna 68 is kept constant. The positional relationship between antennas is an important factor in wireless power supply. It greatly affects the transmission efficiency. In the electromagnetic induction method, it is assumed that the antennas face each other, and in the magnetic resonance and electric field resonance methods, the distance can be an attenuation factor. Therefore, in the past, it was attempted to achieve this by keeping it constant.

FIG. 4 presents a graph of the relationship between the position of the carriage and the transmission efficiency. As a design condition, it can be said that the condition is satisfied if the transmission efficiency in the carriage scanning area 73 is the minimum efficiency value 74 or more assumed in the design. On the other hand, even in this configuration, the distance between the antennas includes variation, which is the accumulation of vibrations caused by the carriage unit during movement and mounting tolerances of both antennas.

FIG. 5 shows a graph of the distance between antennas and the transmission efficiency.

The variation 77 of the distance between the antennas is shown in the carriage scanning region. If this is the minimum efficiency of 78 or more of the design value, it is shown that there is no problem in operation. As described above, in terms of transmission efficiency, the conventional arrangement has an advantage. Here, in FIG. 3, the magnetic flux 69 emitted from the transmitting antenna 67 is shown. It is an object of this embodiment to reduce the magnetic flux that goes out of the machine in this way.

Next, examples of the present proposal will be described with reference to FIGS. 6 and 7.

FIG. 6 shows the configuration.

Unlike the conventional one, the antenna is arranged perpendicular to the operation direction. The transmitting antennas 82 and 83 and the receiving antennas 84 and 85 correspond to them. Unlike the conventional method, the magnetic fluxes 79 and 80 of the electric transmission are not directed to the paper ejection port, and the leakage flux can be reduced. Further, unlike the paper ejection port, it is possible to have a configuration in which the power transmission area is shielded with metal. On the other hand, the difficulty of this configuration is that the transmission efficiency is not stable. As shown in FIG. 5, the distance between the antennas is a large factor in the transmission efficiency.

FIG. 7 shows a diagram of the carriage position and the transmission efficiency.

In this embodiment, since the antennas are arranged on the left and right sides of the carriage, the combination of the two transmissions becomes the entire transmission. The transmission efficiency of the combination of the transmitting antenna 83 and the receiving antenna 85 is shown in the graph 90, and the transmission efficiency of the combination of the transmitting antenna 82 and the receiving antenna 84 is shown in the graph 91. Then, the dashed line 92 is a plot of the combined values. As shown in this graph, in the carriage scanning area 89, the combined transmission efficiency 92 is equal to or higher than the design minimum efficiency value of 88, indicating that this configuration is satisfied.

Further, in the left and right transmission waveforms, the leakage of magnetic flux can be further reduced by changing the antenna control depending on the position of the carriage. Specifically, in the region where the carriage position is close to the antenna 82, the transmission power from the antenna 83 is reduced. On the contrary, in the region where the carriage position is close to the antenna 83, the transmission power from the antenna 82 is reduced. In addition, the interference between the two transmissions can be reduced by shifting the phase. In the case of opposite phase, the left and right leakage fluxes cancel each other out, so that the phase of the AC power supply applied to the left and right antennas is reversed, and the phase of the flying magnetic flux is reversed, so that they can be canceled out in space. That is.

As described above, in the method of this embodiment, it is possible to realize wireless power transmission of the carriage unit, which is a movable part, while reducing the leakage flux.

79 Power transmission magnetic flux 1, 80 Power transmission magnetic flux 2, 81 Carriage scanning area,
82 transmit antenna 1, 83 transmit antenna 2, 84 receive antenna 1,
85 Receiving antenna 2

Claims (4)

A printing device characterized in that transmission / reception antennas are arranged on both sides perpendicular to the operation direction of the printer operation unit in wireless power supply to the printer operation unit. The printing apparatus according to claim 1, further comprising wireless power transmission means on both sides of the carriage unit. The method for controlling a wireless power transmission means according to claim 2, wherein the control of the power transmission is changed according to the position of the carriage unit. The method for controlling a wireless power transmission means according to claim 2, wherein the leakage flux is reduced by shifting the phase of the magnetic flux of the wireless transmission of the antennas on both sides.