JP7574669B2 - Inkjet printer - Google Patents

Description

This disclosure relates to an inkjet printer.

An inkjet printer has a carriage with a print head that ejects ink, and prints characters, images, etc., on the recording medium by ejecting ink from the print head while moving the carriage relative to the recording medium. The position of the carriage is detected and controlled by reading an encoder scale provided on the main body of the inkjet printer with an encoder provided on the carriage.

There is also known technology that eliminates the need to install a power supply cable to the carriage by supplying power in a non-contact manner between multiple primary coils arranged on the main body along the direction of carriage movement and a secondary coil provided on the carriage side.

JP 2010-228447 A

However, with the above-mentioned conventional technology, there was a problem that the carriage position could not be detected properly when the encoder scale became dirty or otherwise abnormal due to ink mist or grease.

The present disclosure aims to provide an inkjet printer that can properly detect the position of the carriage even if an abnormality occurs in the encoder scale.

To solve the above problems, the inkjet printer of the first aspect of the present disclosure includes a main body, a carriage having a print head that ejects ink and capable of reciprocating in a predetermined direction of movement within the main body, a plurality of primary coils arranged in the main body along the direction of movement of the carriage, a power source that supplies AC power to the primary coils, a secondary coil that is provided on the carriage and performs non-contact power transfer between the primary coils, a plurality of sensors that are provided for each of the primary coils and output a signal corresponding to a magnetic field, and a control unit that detects the position of the secondary coil based on the signals received from the plurality of sensors.

According to the above configuration, the control unit detects the position of the secondary coil provided on the carriage using the primary coil. This makes it possible to properly detect the position of the carriage even if an abnormality occurs in the encoder scale.

A second aspect of the present disclosure is the inkjet printer of the first aspect, wherein the carriage further has an encoder for detecting the position of the carriage, and the control unit detects the position of the carriage based on the detection result of the encoder, and when an undetectable section occurs within the movable range of the carriage where the position of the carriage cannot be detected using the encoder, the control unit may determine the position of the carriage in the undetectable section based on the position of the secondary coil detected based on the signal.

With the above configuration, even if the undetectable section occurs, the carriage position can be detected properly.

A third aspect of the present disclosure is an inkjet printer according to the first or second aspect, in which the control unit may move the carriage in the opposite direction when it detects that the secondary coil has approached a primary coil that is located at the end of the multiple primary coils.

The above configuration allows for contactless power supply while making it possible to detect the carriage position for reciprocating carriage movement without providing a dedicated detection means.

A fourth aspect of the present disclosure is an inkjet printer according to any one of the first to third aspects, in which the control unit may stop the carriage at a position where the secondary coil approaches a primary coil that is located at the end of the plurality of primary coils when terminating the movement of the carriage.

With the above configuration, power can be transferred from the primary coil to the secondary coil immediately when printing begins.

A fifth aspect of the present disclosure is an inkjet printer according to any one of the first to fourth aspects, in which AC power may be supplied from the power source to each of the primary coils while the print head is ejecting ink.

The above configuration simplifies the control of power supply to multiple primary coils, reducing the possibility of time loss.

A sixth aspect of the present disclosure is an inkjet printer according to any one of the first to fourth aspects, in which each of the primary coils is provided with a switch that opens and closes the connection of the primary coil to the power source, and the control unit may control the multiple switches to be opened and closed sequentially while the print head is ejecting ink.

With the above configuration, the power supply from the power source is switched sequentially, which reduces power consumption compared to a constant power supply.

A seventh aspect of the present disclosure is the inkjet printer of the sixth aspect, in which the control unit may assign each of the primary coils to one of a plurality of blocks arranged along the moving direction of the carriage, and control the opening and closing of the switch on a block-by-block basis.

The above configuration makes it easy to control the opening and closing of the primary coil switch to follow the movement of the carriage, even when the carriage is moving at high speed.

The eighth aspect of the present disclosure is the inkjet printer of the seventh aspect, in which the control unit may change the number of the primary coils assigned to the block depending on the moving speed of the carriage.

With the above configuration, AC power can be supplied to the primary coil in accordance with the printing speed, and power can be efficiently supplied to the secondary coil at various printing speeds.

A ninth aspect of the present disclosure is an inkjet printer according to any one of the sixth to eighth aspects, in which the control unit may stop the supply of AC power from the power source by opening a corresponding switch when it detects that the secondary coil has come close to an adjacent primary coil in the moving direction of the carriage in each of the plurality of primary coils.

With the above configuration, in each primary coil, the supply of AC power to the primary coil can be stopped when the power supply operation to the secondary coil is completed, thereby achieving power saving.

According to one aspect of the present disclosure, an inkjet printer can be realized that can properly detect the position of the carriage even if an abnormality occurs in the encoder scale.

1 is a block diagram showing a schematic configuration of an inkjet printer according to a first embodiment of the present disclosure. FIG. 2 is a plan view illustrating a configuration of a main part of the inkjet printer. 2A is a cross-sectional view taken along line AA in FIG. 2, and FIG. 2B is a cross-sectional view taken along line BB in FIG. 2 is a diagram illustrating the relationship between a primary coil and a secondary coil included in an inkjet printer. FIG. FIG. 2 is a diagram illustrating a specific circuit configuration of a primary coil included in an inkjet printer. FIG. 1A is a diagram for explaining the output waveform of the encoder when there is no abnormality in the encoder scale included in the inkjet printer, and FIG. 1B is a diagram for explaining the output waveform of the encoder when an abnormality occurs in the encoder scale included in the inkjet printer. 4 is a flowchart illustrating an example of an operation of the inkjet printer. 8 is a flowchart illustrating a subroutine of a coil position detection operation shown in step S2 of FIG. 7; 8 is a flowchart illustrating a subroutine of the encoder correction operation shown in step S3 of FIG. 7; 10 is a flowchart illustrating another example of the operation of the inkjet printer. FIG. 11 is a block diagram showing a schematic configuration of an inkjet printer according to a second embodiment of the present disclosure. 12 is a diagram for explaining a specific circuit configuration of a primary coil included in the inkjet printer shown in FIG. 11.

[Embodiment 1]
An embodiment of the present disclosure will be described below with reference to Figures 1 to 10. In this embodiment, an inkjet printer 1 will be described as an image forming apparatus. Also, the image formation will be described as printing.

[General configuration of inkjet printer]
FIG. 1 is a block diagram showing a schematic configuration of an inkjet printer according to a first embodiment of the present disclosure.

As shown in FIG. 1, the inkjet printer 1 of this embodiment includes a main body 2 and a carriage 14 that is movable relative to the main body 2 and performs printing on a recording medium P (FIG. 2) such as paper. The main body 2 includes a communication unit 3, a main body memory 4, a display unit 5, and a paper feed unit 6. The main body 2 also includes an encoder scale 7, a controller 8, a power source 9, a primary coil 10, and a sensor 11. The main body 2 further includes an ink cartridge 16 and a carriage drive unit 17.

As described in detail below, the carriage 14 is configured to be able to move back and forth in a predetermined direction within the main body 2. The carriage 14 also has a print head 14a, a secondary coil 14b, a storage battery 14c, and a print data receiving unit 14d. The carriage 14 is also provided with an encoder 12.

The communication unit 3 performs two-way data communication with an external device (e.g., a computer terminal) of the inkjet printer 1 via a wired or wireless network. The communication unit 3 also transmits print data to be printed to the print data receiving unit 14d of the carriage 14 according to instructions from the controller 8.

The main memory 4 is a memory from which information can be read and written. The main memory 4 is, for example, a flash ROM or an EEPROM (registered trademark). The main memory 4 stores predetermined information such as the number of pages printed.

The display unit 5 includes a liquid crystal display, a lamp, etc., and displays predetermined information. The display unit 5 may also be configured to function as an input unit that accepts instructions from the user by being integrated with a touch panel.

The paper feed unit 6 includes a paper feed tray (not shown) that stores recording media, and a paper feed roller that feeds the recording media from the paper feed tray to the carriage 14. The paper feed unit 6 is also provided opposite the carriage 14, and includes a transport path that transports the recording media fed by the paper feed roller, and a transport roller that transports the recording media on the transport path.

The encoder scale 7 and the encoder 12 are detection devices for detecting the position of the carriage 14, and the encoder scale 7 is fixed to the main body 2. The encoder 12 also moves with the carriage 14, and is able to detect the position of the carriage 14 by reading the encoder scale 7.

The controller 8 is a control unit that controls each part of the inkjet printer 1, and includes, for example, an ASIC (Application Specific Integrated Circuit). The controller 8 executes various processes to cause the inkjet printer 1 to perform printing and associated processes.

The controller 8 may include a processor such as a CPU. In this case, a control program that realizes the print control method may be stored in the main memory 4. The processor of the controller 8 may then operate in accordance with the control program stored in the main memory 4 to execute the print process in the inkjet printer 1.

The controller 8 itself may also be provided with a computer-readable recording medium that stores the control program. As the recording medium, a "non-transient tangible medium" such as a ROM (Read Only Memory) or a magnetic disk, card, semiconductor memory, programmable logic circuit, etc. may be used. A RAM (Random Access Memory) on which the control program is deployed may also be used.

The control program may also be supplied to the computer via any transmission medium capable of transmitting the control program (such as a communication network or broadcast waves).

The controller 8 also has a position detection unit 8a that detects the position of the carriage 14 based on the detection result of the encoder 12, and a coil position detection unit 8b that detects the position of the secondary coil 14b based on signals received from the multiple sensors 11. A method for detecting the position of the secondary coil 14b will be described later. The controller 8 also has a discrimination unit 8c that discriminates the primary coil 10 located at the end of the multiple primary coils 10 based on the position of the secondary coil 14b detected by the coil position detection unit 8b.

In addition, in the controller 8, when the position detection unit 8a is unable to detect the position of the carriage 14 based on the detection results of the encoder 12, the position detection unit 8a determines and detects the position of the carriage 14 using the position of the secondary coil 14b detected by the coil position detection unit 8b.

The primary coil 10 has multiple, for example, nine, primary coils 10a to 10i (Figure 4) arranged on the main body 2 along the direction of movement of the carriage 14.

The sensor 11 is, for example, a magnetic sensor, which is provided for each primary coil 10 and outputs a signal corresponding to the magnetic field. In other words, in the inkjet printer 1 of this embodiment, multiple sensors 11, for example, nine sensors 11, are provided near the corresponding primary coils 10, and when a magnetic field is generated between the primary coil 10 and the secondary coil 14b, each sensor 11 outputs a signal corresponding to the generated magnetic field to the coil position detection unit 8b.

The sensor 11 may be a sensor whose sensing unit outputs a signal according to a magnetic field. However, other sensors such as a voltmeter, ammeter, or a detection circuit that appropriately combines a capacitor, or other sensors that output a signal according to a magnetic field in the vicinity of the primary coil 10, may also be used as the sensor 11.

The print head 14a ejects ink from a nozzle at the tip, for example. In addition, in the inkjet printer 1 of this embodiment, in order to form a full-color image, for example, four print heads 14a are provided that eject ink of different colors (e.g., cyan, magenta, yellow, and black).

The secondary coil 14b is provided on the carriage 14 so as to sequentially face each of the nine primary coils 10a to 10i as the carriage 14 moves. For example, the secondary coil 14b is provided vertically above each of the primary coils 10a to 10i so as to face each of the primary coils 10a to 10i, and transmits power contactlessly between the secondary coil 14b and each of the primary coils 10a to 10i. In other words, when the secondary coil 14b faces any one of the primary coils 10, the secondary coil 14b generates a voltage in response to the magnetic field generated by that primary coil 10.

The storage battery 14c is charged with power from the secondary coil 14b. The storage battery 14c also supplies power to electrical components such as the print head 14a and the print data receiving unit 14d mounted on the carriage 14.

The print data receiving unit 14d receives print data from the communication unit 3 of the main body 2. Then, in the carriage 14, the print head 14a ejects ink based on the received print data to perform printing on the recording medium P.

The ink cartridges 16 are filled with ink. The ink cartridges 16 are connected to the print head 14a via an ink supply tube T (Figure 2). In other words, the inkjet printer 1 of this embodiment is provided with four ink cartridges 16 filled with ink of one of the four colors, and each of the four colors of ink is supplied from the ink cartridges 16 to the print head 14a via the ink supply tube T.

The carriage drive unit 17 moves the carriage 14 in a predetermined direction within the main body 2 according to instructions from the controller 8.

[Main components of the inkjet printer]
Fig. 2 is a plan view illustrating the main configuration of the inkjet printer, Fig. 3A is a cross-sectional view taken along line A-A in Fig. 2, and Fig. 3B is a cross-sectional view taken along line B-B in Fig. 2.

As shown in FIG. 2, the inkjet printer 1 of this embodiment is provided with a printing unit 13 that performs printing processing on a recording medium P. In the printing unit 13, the recording medium P is transported by the paper feed unit 6 from the lower side to the upper side in FIG. 2 as appropriate. In addition, in the printing unit 13, the carriage 14 is driven by a carriage drive unit 17 to reciprocate in the left-right direction in FIG. 2.

The printing unit 13 is also provided with two guide members 18, 19 arranged opposite each other at a predetermined distance, and the carriage 14 moves along the guide members 18, 19 while being positioned above the guide members 18, 19.

In the carriage 14, the print head 14a is positioned above the recording medium P between the guide members 18 and 19, and the printing process is performed by ejecting ink from nozzles provided on the underside of the print head 14a onto the recording medium P below.

As shown in Figures 2, 3A, and 3B, the guide member 18 is constructed using a plate material with an L-shaped cross section. The guide member 18 has a sliding surface 18a on which the sliding surface 14g provided on the carriage 14 slides when the carriage 14 moves, and a protruding portion 18b that protrudes toward the carriage 14 at one end of the sliding surface 18a.

The guide member 19 is constructed using a plate material with a C-shaped cross section, and has protrusions 19a, 19b that protrude toward the carriage 14 at one end and the other end, respectively. Protrusion 19a has a sliding surface 19a1 against which sliding surface 14e provided on carriage 14 slides when carriage 14 moves. Protrusion 19b has a sliding surface 19b1 against which sliding surface 14f provided on carriage 14 slides when carriage 14 moves.

In addition, grease is applied to the sliding surfaces 18a, 19a1, and 19b1 of the guide members 18 and 19, allowing the carriage 14 to move smoothly.

The carriage drive unit 17 is provided on a guide member 19 and includes a drive belt 17a to which the carriage 14 is fixed, and pulleys 17b and 17c that are rotatably provided on the guide member 19 and around which the drive belt 17a is wound. In the carriage drive unit 17, a drive motor (not shown) is connected to the pulley 17b, and the drive motor rotates the pulley 17b, thereby rotating the drive belt 17a and the pulley 17c. This causes the carriage 14 to reciprocate in the left-right direction in FIG. 2.

The encoder scale 7 is disposed on the guide member 19 between the protrusion 19b and the drive belt 17a along the movement direction of the carriage 14. The encoder scale 7 is made of a flexible material such as synthetic resin, and one end is fixed to the guide member 19. The other end of the encoder scale 7 is attached to the guide member 19 via a tension member such as a spring, and the encoder scale 7 is provided on the guide member 19 in a state in which deformation such as bending is minimized.

As a result, in the inkjet printer 1 of this embodiment, the accuracy with which the encoder 12 detects the position of the carriage 14 is reduced from being reduced due to deformation of the encoder scale 7.

The encoder scale 7 has multiple slits 7a (Figure 6A) that are opened at predetermined intervals along the movement direction of the carriage 14.

The encoder 12 is fixed to the underside of the carriage 14. For example, a transmission type detector is used for the encoder 12, and as shown in FIG. 3A and FIG. 3B, the encoder 12 has a light-emitting section 12a that emits a predetermined light and a light-receiving section 12b that receives the light from the light-emitting section 12a. The light-emitting section 12a and the light-receiving section 12b are arranged to sandwich the encoder scale 7.

When the light-emitting unit 12a faces the slit 7a of the encoder scale 7, the light-receiving unit 12b receives light from the light-emitting unit 12a and outputs a high-level signal indicating that light has been received to the position detection unit 8a. This allows the controller 8 to detect the position of the carriage 14 based on the detection result of the encoder 12.

In addition to the above description, for example, a reflective encoder can be used in which the light-emitting unit and the light-receiving unit are arranged side by side on the surface of the encoder scale 7, and the light-receiving unit receives light from the light-emitting unit that is reflected by the encoder scale 7.

A protective film TP is provided between the encoder scale 7 and the sliding surface 19b1 of the guide member 19 so as to cover the entire surface of the encoder scale 7. The protective film TP significantly reduces the possibility that the sliding surface 19b1, the recording medium P, or the user's hand will come into contact with the encoder scale 7.

This minimizes the possibility of the grease applied to the sliding surface 19b1 adhering to the encoder scale 7 or deformation such as bending, thereby reducing the deterioration of the detection accuracy of the carriage 14 by the encoder 12.

Below the encoder scale 7, as shown by the two-dot chain line in FIG. 2, there is provided an installation area PA in which the primary coils 10 are installed. In other words, in the installation area PA, multiple primary coils 10 are provided at predetermined intervals along the movement direction of the carriage 14.

As described above, in the carriage 14, as illustrated in Figs. 2 and 3A, the secondary coil 14b is provided near the encoder 12 on the underside of the carriage 14 so as to face the primary coil 10 above the installation area PA. This allows the secondary coil 14b to face one of the primary coils 10 depending on the movement of the carriage 14.

In addition to the above description, the primary coil 10 may be installed at other locations on the guide members 18, 19. For example, the primary coil 10 may be installed on the surface of the protrusion 18b on the carriage 14 side. When the primary coil 10 is installed in this manner, the secondary coil 14b is installed on the underside of the carriage 14 so as to face the primary coil 10 between the primary coil 10 and the print head 14a.

Furthermore, in addition to the above description, a primary coil 10 may be installed on the back surface of the top cover (not shown) of the main body 2 above the carriage 14, facing the top surface of the carriage 14, and a secondary coil 14b may be installed on the top surface of the carriage 14 so as to face the primary coil 10.

[Example of configuration of primary coil and secondary coil]
Fig. 4 is a diagram for explaining the relationship between the primary coil and the secondary coil included in the inkjet printer, and Fig. 5 is a diagram for explaining a specific circuit configuration of the primary coil included in the inkjet printer.

As shown in FIG. 4, nine primary coils 10a-10i are arranged in a line along the direction of movement of the carriage 14. Furthermore, as shown in FIG. 5, the primary coils 10a-10i are connected to a power source 9. In the inkjet printer 1 of this embodiment, while the print head 14a is ejecting ink, AC power is supplied from the power source 9 to each of the primary coils 10a-10i. The current flowing through each of the primary coils 10a-10i generates a magnetic flux in each, generating a magnetic field in the vicinity.

In this way, in the inkjet printer 1 of this embodiment, AC power is supplied to each of the primary coils 10a to 10i while the print head 14a is ejecting ink. As a result, it is possible to simplify the control of the power supply to the multiple primary coils 10a to 10i, and reduce the possibility of time loss.

The secondary coil 14b also moves left and right in FIG. 4 as the carriage 14 moves. When a magnetic field is generated near each of the primary coils 10a to 10i, the secondary coil 14b transmits power contactlessly to the closest primary coil 10. That is, in the secondary coil 14b, an induced current is generated by electromagnetic induction with the closest primary coil 10, and the generated induced current is supplied to the storage battery 14c and stored in the storage battery 14c. In this way, power is supplied contactlessly to the carriage 14 from the power source 9 of the main body 2 via the secondary coil 14b and the primary coil 10 electromagnetically coupled to the secondary coil 14b.

In addition, when an induced current flows through the secondary coil 14b, the magnetic field changes in the primary coil 10 that is electromagnetically coupled to the secondary coil 14b. This can be used to identify the primary coil 10 that is close to the secondary coil 14b.

Therefore, the coil position detection unit 8b can detect the position of the secondary coil 14b, and therefore the position of the carriage 14, based on the signals received from the multiple sensors 11.

[Example of detection results from the position detection unit]
FIG. 6A is a diagram for explaining the output waveform of the encoder when no abnormality occurs in the encoder scale included in the inkjet printer, and FIG. 6B is a diagram for explaining the output waveform of the encoder when an abnormality occurs in the encoder scale included in the inkjet printer.

As shown in FIG. 6A, the encoder scale 7 has alternating slits 7a and blocking sections 7b that block the openings of the slits 7a. In the encoder 12, when the light receiving section 12b faces the slits 7a, a high-level signal is output to the position detection section 8a, and when the light receiving section 12b faces the blocking section 7b, a low-level signal is output to the position detection section 8a.

In other words, the encoder 12 outputs high-level and low-level signals alternately at a predetermined cycle. The position detection unit 8a, for example, counts the number of times a high-level signal is input from the encoder 12, and uses the count result as the number of pulses counted from the encoder 12. The position detection unit 8a then uses the count number to determine the movement distance of the carriage 14 from one end position in the movement direction of the carriage 14, which is set as the home position of the carriage 14, and detects the position of the carriage 14.

Then, the controller 8 drives the carriage drive unit 17 based on the position of the carriage 14 detected by the position detection unit 8a to control the position of the carriage 14.

The position detection unit 8a also uses the count number of the above pulses to control the movement speed of the carriage 14 and the timing of ink ejection from the print head 14a.

Also, as shown in FIG. 6B, when an abnormality occurs in the encoder scale 7, the signal from the encoder 12 changes according to the abnormality that has occurred. Specifically, when ink mist or grease adheres to the encoder scale 7, the slits 7a may be blocked, resulting in the formation of light-shielding sections 7d that block the light from the light-emitting section 12a.

When the light-shielding portion 7d described above occurs on the encoder scale 7, an abnormality occurs in the encoder scale 7, and the encoder 12 outputs only a low-level signal when the light-receiving portion 12b faces the light-shielding portion 7d. As a result, the position detection portion 8a cannot detect the position of the carriage 14 using the detection result of the encoder 12.

Therefore, in the inkjet printer 1 of this embodiment, in an undetectable section where the position detection unit 8a cannot detect the position of the carriage 14, the controller 8 determines the position of the carriage 14 by the coil position detection unit 8b based on the position of the secondary coil 14b detected based on the signal received from the sensor 11. As a result, in the inkjet printer 1 of this embodiment, the position of the carriage 14 can be properly detected even if the above-mentioned undetectable section occurs.

[Example of inkjet printer operation]
Fig. 7 is a flow chart for explaining an example of the operation of the inkjet printer. Fig. 8 is a flow chart for explaining the subroutine of the coil position detection operation shown in step S2 of Fig. 7. Fig. 9 is a flow chart for explaining the subroutine of the encoder correction operation shown in step S3 of Fig. 7. Fig. 10 is a flow chart for explaining another example of the operation of the inkjet printer.

Figures 7 to 9 explain the processing procedure of the inkjet printer 1, including processing related to position control of the carriage 14. The processing procedure explained here is an example of a control method for controlling the inkjet printer 1 by the controller 8.

When the controller 8 receives an instruction to execute a printing operation via the communication unit 3 or the display unit 5, as shown in FIG. 7, the position detection unit 8a judges whether or not an abnormality has occurred in the encoder detection operation based on the signal from the encoder 12 (S1). Specifically, the position detection unit 8a judges whether or not an abnormality has occurred in the encoder detection operation by determining whether or not the level of the signal from the encoder 12 remains the same for a certain period of time, or whether or not the signal from the encoder 12 changes between a high level signal and a low level signal outside the above-mentioned predetermined period.

If it is determined that an abnormality has occurred in the encoder detection operation (YES in S1), the coil position detection unit 8b executes the secondary coil position detection operation described below (S2). Furthermore, the coil position detection unit 8b executes the encoder correction operation described below (S3).

On the other hand, if it is determined that no abnormality has occurred in the encoder detection operation (NO in S1), the position detection unit 8a uses the signal from the encoder 12 to control the carriage 14 (S4).

The controller 8 determines whether the printing operation has ended (S5). If it is determined that the printing operation has not ended (NO in S5), the flow proceeds to step S1.

On the other hand, if it is determined that the printing operation has ended (YES in S5), the inkjet printer 1 ends its operation.

As shown in FIG. 8, in the secondary coil position detection operation, the coil position detection unit 8b detects the position of the secondary coil 14b based on signals received from the multiple sensors 11. Furthermore, the position detection unit 8a detects the position of the carriage 14 based on the position of the secondary coil 14b detected by the coil position detection unit 8b, and refers to the time series of positions to determine whether the movement direction of the carriage 14 is, for example, to the right (S6).

Specifically, when the coil position detection unit 8b detects that the secondary coil 14b is moving to the right or left relative to the nine primary coils 10a to 10i shown in FIG. 4, the position detection unit 8a determines that the carriage 14 is moving to the right or left.

If it is determined that the movement direction of the carriage 14 is to the right (YES in S6), the position detection unit 8a sets A=n-1 and B=n as the numbers of the primary coils 10 located to the left and right of the position where an abnormality in the encoder detection operation was detected in step S1, respectively (S7).

On the other hand, if it is determined that the movement direction of the carriage 14 is leftward (NO in S6), the position detection unit 8a sets C=n+1 and B=n as the numbers of the primary coils 10 located to the left and right of the position where an abnormality in the encoder detection operation was detected in step S1, respectively (S8).

As shown in FIG. 9, in the encoder correction operation, the position detection unit 8a determines the number of steps that serves as the basis for the movement of the carriage 14 based on the position of the primary coil 10 defined by B and A or C set in step S7 or step S8, and the print resolution that is preset according to the printing process (S10).

Specifically, the position detection unit 8a calculates the number K of sections of the primary coil 10 included in the section where an abnormality occurs in the encoder detection operation based on the set B and A or C. The position detection unit 8a obtains the number of steps by multiplying the separation distance W between two adjacent primary coils 10, the number K of sections, and the printing resolution SP (dpi).

Next, the position detection unit 8a determines whether the position of the carriage 14 is within a range in which an abnormality occurs in the encoder detection operation (S11).

If it is determined that the position of the carriage 14 is within the range of an area where an abnormality occurs in the encoder detection operation (YES in S11), the position detection unit 8a controls the carriage 14 using the number of steps obtained in step S10 (S12).

In other words, the number of steps indicates the number of dots (the number of ink ejections from the print head 14a) in the printing process included in the section where an abnormality occurs in the encoder detection operation, so the position detection unit 8a controls the carriage 14 by controlling the timing of ink ejection from the print head 14a using the number of dots and the movement speed of the carriage 14, which is determined by the print resolution.

On the other hand, if it is determined that the position of the carriage 14 is not within the range where an abnormality occurs in the encoder detection operation (NO in S11), the position detection unit 8a uses the detection result of the encoder 12 to control the carriage 14 (S13).

Figure 10 describes the processing procedure of the inkjet printer 1, including processing related to setting and controlling the home position of the carriage 14. This setting and control of the home position of the carriage 14 is an example of an operation that is executed when the printing operation of step S5 is completed.

As shown in FIG. 10, the coil position detection unit 8b detects the position of the secondary coil 14b based on signals received from the multiple sensors 11, and furthermore, the coil position detection unit 8b sets the primary coil 10 that is closest to the secondary coil 14b among the primary coils 10a to 10i as X=m (S14).

Next, the coil position detection unit 8b assigns numbers in sequence, for example, a=1, b=2, ..., i=9 to the primary coils 10a to 10i shown in FIG. 4, from the primary coil 10a at the left end to the primary coil 10i at the right end. The coil position detection unit 8b then determines whether the number of the primary coil 10 set as X=m in step S14 is 5 or greater (S15).

If it is determined that the number of the primary coil 10 set as X=m is 5 or more (YES in S15), the discrimination unit 8c determines that the carriage 14 is located near the right end. Then, the controller 8 moves the carriage 14 to the right (S16). Furthermore, the controller 8 sets the primary coil 10i to the home position of the carriage 14 (S18).

On the other hand, if it is determined that the number of the primary coil 10 set as X=m is not 5 or more (NO in S15), the discrimination unit 8c determines that the carriage 14 is located near the left end. Then, the controller 8 moves the carriage 14 to the left (S17). Furthermore, the controller 8 sets the primary coil 10a to the home position of the carriage 14 (S18).

The reason why the number "5" is used as the judgment value for the primary coil 10 with X=m set in step S15 is that in this embodiment, nine primary coils 10a-10i are used, and the number assigned to the primary coil 10e located at the center of the carriage 14 in the moving direction is used as the judgment value. This makes it easy to perform the optimal setting operation for the home position of the carriage 14.

In this way, when the controller 8 ends the movement of the carriage 14, it stops the carriage 14 at a position where the secondary coil 14b approaches the primary coil 10a or 10i that is located at the extreme end of the multiple primary coils 10a to 10i. This makes it possible in this embodiment to immediately transfer power from the primary coil 10a or 10i to the secondary coil 14b when the next printing starts.

In addition, when the printing operation is not completed, the controller 8 can also control the carriage 14 using the detection results of the coil position detection unit 8b.

Specifically, when the coil position detection unit 8b detects that the secondary coil 14b has approached the primary coil 10a or 10i that is located at the end of the multiple primary coils 10a to 10i, the carriage 14 can be moved in the opposite direction. This makes it possible to realize non-contact power supply while detecting the position of the carriage 14 for reciprocating movement of the carriage 14 without providing a dedicated detection means.

As described above, in the inkjet printer 1 of this embodiment, the coil position detection unit 8b of the controller 8 detects the position of the secondary coil 14b provided on the carriage 14 using the primary coil. As a result, in the inkjet printer 1 of this embodiment, even if an abnormality occurs in the encoder scale 7, the position of the carriage 14 can be properly detected.

[Embodiment 2]
Other embodiments of the present disclosure will be described below. For convenience of explanation, the same reference numerals will be given to components having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

Figure 11 is a block diagram showing a schematic configuration of an inkjet printer according to a second embodiment of the present disclosure. Figure 12 is a diagram explaining a specific circuit configuration of a primary coil included in the inkjet printer shown in Figure 11.

In the figure, the difference between this embodiment and the first embodiment is that a switch is provided between the power source and the primary coil.

As shown in Figures 11 and 12, in the inkjet printer 1 of this embodiment, the main body 2 is provided with a switch 20 that opens and closes the connection of the primary coil to the power source 9. A switch 20 is provided for each of the multiple primary coils 10a to 10i. In other words, in the inkjet printer 1 of this embodiment, nine switches 20a to 20i are installed.

The controller 8 controls the multiple switches 20a-20i to open and close sequentially while the print head 14a ejects ink. As a result, in the inkjet printer 1 of this embodiment, the power supply from the power source 9 is switched sequentially, making it possible to reduce power consumption compared to a constant power supply. In other words, by eliminating power consumption in the primary coil 10 that is not involved in power transmission to the secondary coil 14b, it is possible to reduce power consumption overall.

In addition to the above description, for example, the controller 8 may assign each of the primary coils 10a to 10i to one of a number of blocks arranged along the movement direction of the carriage 14, and control the opening and closing of the switches 20a to 20i on a block-by-block basis.

In this case, even if the carriage 14 moves at high speed, it becomes easy to control the opening and closing of the switch 20 of the primary coil 10 to follow the movement of the carriage 14.

The controller 8 can also change the number of primary coils 10 assigned to the above blocks depending on the movement speed of the carriage 14.

In this case, AC power can be supplied to the primary coil 10 in accordance with the printing speed of the printing unit 13, and power can be efficiently supplied to the secondary coil 14b at various printing speeds.

This disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of this disclosure.

Reference Signs List 1 Inkjet printer 2 Main body 8 Controller (control unit)
9 Power supply 10, 10a to 10i Primary coil 11 Sensor 12 Encoder 14 Carriage 14a Print head 14b Secondary coil 20 Switch

Claims (9)

The main body,
a carriage having a print head that ejects ink and capable of reciprocating in a predetermined moving direction within the main body;
a plurality of primary coils arranged in the main body along the moving direction of the carriage;
a power source for supplying AC power to the primary coil;
a secondary coil provided on the carriage and configured to perform non-contact power transmission between the secondary coil and the primary coil;
A plurality of sensors are provided for each of the primary coils, and each sensor outputs a signal corresponding to a magnetic field;
and a control unit that detects a position of the secondary coil based on the signals received from the plurality of sensors. the carriage further includes an encoder for detecting a position of the carriage;
The control unit detects a position of the carriage based on a detection result of the encoder, and
2. The inkjet printer according to claim 1, wherein, when an undetectable section occurs within a movable range of the carriage, in which the position of the carriage cannot be detected using the encoder, the position of the carriage in the undetectable section is determined based on the position of the secondary coil detected based on the signal. The control unit is
3. The inkjet printer according to claim 1, further comprising a step of moving the carriage in the opposite direction when it is detected that the secondary coil approaches a primary coil located at the end of the plurality of primary coils. The control unit is
4. The inkjet printer according to claim 1, wherein when the movement of the carriage is to be terminated, the carriage is stopped at a position where the secondary coil approaches a primary coil that is located at the end of the plurality of primary coils. The inkjet printer according to any one of claims 1 to 4, wherein AC power is supplied from the power source to each of the primary coils while the print head is ejecting ink. Each of the primary coils is provided with a switch for opening and closing a connection of the primary coil to the power source,
The control unit is
5. The inkjet printer according to claim 1, wherein the switches are controlled so that they are opened and closed sequentially while the print head is ejecting ink. The control unit is
each of the primary coils is assigned to one of a plurality of blocks arranged along the moving direction of the carriage;
7. The inkjet printer according to claim 6, wherein opening and closing of said switches is controlled in units of said blocks. The control unit is
8. The inkjet printer according to claim 7, wherein the number of the primary coils allocated to the block is changed in accordance with a moving speed of the carriage. The inkjet printer according to any one of claims 6 to 8, wherein the control unit, when detecting that the secondary coil is approaching an adjacent primary coil in the moving direction of the carriage, stops the supply of AC power from the power source by opening a corresponding switch.

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