JP7386720B2 - inkjet printer - Google Patents

Description

The present invention relates to an inkjet printer equipped with an ink warming mechanism for warming ink supplied to an inkjet head.

Conventionally, an ink supply device for supplying ink to a print head chip is known (for example, see Patent Document 1). The ink supply device described in Patent Document 1 includes an ink storage section that stores ink to be supplied to a print head chip. The ink storage section is formed in the shape of a flat rectangular parallelepiped, and an ink storage space is formed in the ink storage section. Further, the ink supply device described in Patent Document 1 includes a preheating plate and a preheating heater for heating ink supplied to a print head chip.

In the ink supply device described in Patent Document 1, an ink storage section stores ink that flows through a preheating plate. The preheating heater and the preheating plate are formed in a rectangular flat plate shape. The outer shape of the preheating heater and the outer shape of the preheating plate are the same. The preheating heater is disposed between the preheating plate and the ink storage section, and heats the ink passing through the preheating plate and the ink stored in the ink storage section.

In the ink supply device described in Patent Document 1, a temperature sensor is attached to the surface of the preheating plate. In this ink supply device, an appropriate reference temperature is set in advance according to the viscosity of the ink used, and the temperature measured by the temperature sensor is compared with the reference temperature. Also, if the temperature measured by the temperature sensor is lower than the reference temperature, power is supplied to the preheating heater and the preheating heater generates heat, and if the temperature measured by the temperature sensor is higher than the reference temperature, power is not supplied to the preheating heater. will be stopped.

Japanese Patent Application Publication No. 2006-213061

In the ink supply device described in Patent Document 1, a temperature sensor is attached to the surface of a preheating plate that has the same outer shape as that of a preheater. Therefore, in this ink supply device, the heat of the preheater is likely to be directly transmitted to the temperature sensor via the preheating plate, and the influence of the preheater on the detection result of the temperature sensor may become large. If the influence of the preheating heater on the detection result of the temperature sensor becomes large, it becomes difficult for the temperature sensor to properly detect the temperature of the ink passing through the preheating plate, and as a result, the ink cannot be adjusted based on the detection result of the temperature sensor. There is a risk that the product may not be heated to the appropriate temperature. Furthermore, if the ink cannot be heated to an appropriate temperature, there is a risk that the viscosity of the ink supplied to the print head chip will vary widely.

Therefore, an object of the present invention is to suppress variations in the viscosity of ink supplied from the ink warming mechanism to the inkjet head in an inkjet printer equipped with an ink warming mechanism for warming ink supplied to the inkjet head. Our goal is to provide a capable inkjet printer.

In order to solve the above problems, an inkjet printer of the present invention includes an inkjet head that discharges ink, and an ink warming mechanism that warms the ink supplied to the inkjet head. A block-shaped heating unit body in which an ink passing section is formed, a heater attached to the heating unit body to heat the heating unit body, and a heater attached to the heating unit body to heat the heating unit body. The ink passage section includes a temperature sensor that detects temperature and a heater control section that controls the heater based on the detection result of the temperature sensor. The main body of the heating unit is formed with a heater attachment part to which a heater is attached and a sensor attachment part to which a temperature sensor is attached.If the flow direction of ink flowing into the ink passage part is the ink flow direction, the sensor The attachment portion is characterized in that it is provided so as to protrude upstream of the heater attachment portion in the ink flow direction.

In the inkjet printer of the present invention, the heating section main body in which the ink passage section is formed has a heater attachment section to which the heater is attached and a sensor attachment section to which the temperature sensor is attached; Assuming that the flow direction of ink flowing into the ink flow direction is defined as the ink flow direction, the sensor mounting portion is provided so as to protrude upstream of the heater sticking portion in the ink flow direction. That is, in the present invention, the temperature sensor is attached to the sensor attachment portion that protrudes upstream in the ink flow direction of the heater attachment portion.

Therefore, in the present invention, it becomes difficult for the heat of the heater to be directly transmitted to the temperature sensor, and it becomes possible to reduce the influence of the heater on the detection result of the temperature sensor. Therefore, in the present invention, the temperature of the ink passing through the ink passage can be appropriately detected by the temperature sensor via the heating unit main body, and as a result, the temperature of the ink passing through the ink passage path can be appropriately detected by the temperature sensor. , it becomes possible to appropriately control the heater so as to suppress variations in the temperature of ink supplied to the inkjet head. Therefore, in the present invention, it is possible to suppress variations in the viscosity of the ink supplied from the ink warming mechanism to the inkjet head.

Furthermore, in the present invention, since the temperature sensor is attached to the sensor attachment part that protrudes upstream in the ink flow direction of the heater attachment part, the temperature of the ink before being warmed by the heater is reflected in the detection result of the temperature sensor. It becomes easier. Therefore, in the present invention, it is possible to control the heater reflecting the external temperature (environmental temperature) of the inkjet printer based on the detection result of the temperature sensor. For example, if the external temperature of the inkjet printer is low and the temperature of the ink before it is warmed by the heater is low, the temperature detected by the temperature sensor is likely to be low. It becomes possible to increase the heating temperature. In addition, if the external temperature of the inkjet printer is high and the temperature of the ink before it is warmed by the heater is high, the temperature detected by the temperature sensor is likely to be high. It becomes possible to lower the heating temperature. As a result, in the present invention, it is possible to effectively suppress variations in the viscosity of the ink supplied from the ink warming mechanism to the inkjet head.

Furthermore, in the present invention, since the sensor attachment part is provided to protrude upstream of the heater attachment part in the ink flow direction, for example, a part of the heater attached to the heater attachment part is cut out, and the heater attachment part is cut out. There is no need to attach a temperature sensor to the cutout. Therefore, in the present invention, it becomes possible to attach the heater to the entire heater attachment section, and as a result, it becomes possible to efficiently heat the heating section main body with the heater.

In the present invention, the inkjet printer includes a pressure adjustment mechanism that accommodates ink supplied to the ink passage section and adjusts the pressure of the ink supplied to the inkjet head, and at least a part of the pressure adjustment mechanism is heated. A second ink flow path through which ink flows is formed inside the pressure adjustment mechanism, and the sensor mounting portion is connected to the outer surface of the portion of the pressure adjustment mechanism where the second ink flow path is formed. Preferably, they are close together. With this configuration, the temperature of the ink before being warmed by the heater is more likely to be reflected in the detection result of the temperature sensor. Therefore, based on the detection result of the temperature sensor, it is possible to control the heater in a way that better reflects the external temperature of the inkjet printer. As a result, it becomes possible to more effectively suppress variations in the viscosity of the ink supplied from the ink warming mechanism to the inkjet head.

In the present invention, the heating section main body may be formed with a pressure adjustment mechanism housing part in which a part of the pressure adjustment mechanism is housed, and the sensor mounting part may constitute a part of the pressure adjustment mechanism housing part. preferable. With this configuration, it becomes possible to attach the temperature sensor to the heating unit main body using the pressure adjustment mechanism housing part in which a part of the pressure adjustment mechanism is accommodated. Therefore, even if the sensor attachment portion is formed on the heating section main body, it is possible to simplify the configuration of the heating section main body.

In the present invention, for example, the pressure adjustment mechanism is disposed above the ink passage section, and the sensor attachment section is disposed above the heater attachment section.

In the present invention, the heater control section controls the heater based on the detection result of the temperature sensor so that the temperature of the heating section main body becomes a predetermined reference temperature, and also performs heating due to the influence of ink flowing into the ink passage section. Calculating the amount of temperature decrease of the heating section body based on the detection result of the temperature sensor after ink discharge from the inkjet head starts, and updating the reference temperature based on the calculated amount of temperature decrease of the heating section body. is preferred. With this configuration, when the amount of temperature drop in the heating unit main body due to the influence of ink flowing into the ink passage section is large, and it is estimated that the amount of ink flowing into the ink passage section per unit time is large, , it is possible to update the reference temperature to a higher temperature, and the amount of temperature drop of the heating unit main body due to the influence of ink flowing into the ink passage section is small, and the amount of ink flowing into the ink passage section per unit time is reduced. When it is estimated that the inflow amount is small, it becomes possible to update the reference temperature to a lower temperature.

Therefore, when the amount of ink supplied from the ink heating mechanism to the inkjet head per unit time increases and the time required for ink to pass through the ink passage section becomes shorter, the reference temperature is updated to a higher temperature. It is possible to control the heater based on the detection result of the temperature sensor and to heat the ink supplied to the inkjet head to a predetermined temperature, and also to control the unit of ink supplied to the inkjet head from the ink heating mechanism. When the amount of ink supplied per hour decreases and the time it takes for ink to pass through the ink passage section becomes longer, the heater is controlled based on the reference temperature updated to a lower temperature and the detection result of the temperature sensor, and the inkjet It becomes possible to prevent the ink supplied to the head from being heated above a predetermined temperature. As a result, it becomes possible to effectively suppress variations in the viscosity of the ink supplied from the ink warming mechanism to the inkjet head.

In the present invention, the inkjet printer includes a second temperature sensor for detecting the external temperature of the inkjet printer, and the heater control section detects the detection result of the second temperature sensor before ink is ejected from the inkjet head. It is preferable to initially set the reference temperature based on.

If the external temperature of an inkjet printer is high, the temperature of the ink flowing into the ink passage section will be high, so even if the amount of heat applied to the ink passing through the ink passage section is small, the ink supplied to the inkjet head cannot be heated to a specified temperature. While it is possible to heat the inkjet printer, if the external temperature of the inkjet printer is low, the temperature of the ink flowing into the ink passage section will be low, so if the amount of heat applied to the ink passing through the ink passage section is not large, Although it becomes difficult to heat the ink supplied to the inkjet head to a predetermined temperature, with this configuration, when the external temperature of the inkjet printer is high, the reference temperature is set based on the detection result of the second temperature sensor. It becomes possible to initially set the reference temperature to a low temperature, and when the external temperature of the inkjet printer is low, it becomes possible to initially set the reference temperature to a high temperature based on the detection result of the second temperature sensor.

Therefore, when the external temperature of the inkjet printer is high, the heater is controlled based on the reference temperature, which is initially set to a low temperature, and the detection results of the temperature sensor to heat the ink supplied to the inkjet head to a predetermined temperature. In addition, when the external temperature of the inkjet printer is low, the heater is controlled based on the reference temperature, which is initially set to a high temperature, and the detection results of the temperature sensor, and the ink supplied to the inkjet head is controlled. can be heated to a predetermined temperature. Therefore, regardless of the external temperature of the inkjet printer, it is possible to heat the ink supplied to the inkjet head to a predetermined temperature. This makes it possible to suppress variations in the viscosity of ink supplied to the printer.

As described above, in the present invention, in an inkjet printer equipped with an ink warming mechanism for warming ink supplied to the inkjet head, it is possible to suppress variations in the viscosity of the ink supplied from the ink warming mechanism to the inkjet head. becomes possible.

1 is a perspective view of an inkjet printer according to an embodiment of the present invention. 2 is a schematic diagram for explaining the configuration of the inkjet printer shown in FIG. 1. FIG. FIG. 3 is a perspective view of a portion of the peripheral portion of the carriage shown in FIG. 2; 4 is a sectional view of the pressure adjustment mechanism shown in FIG. 3. FIG. FIG. 4 is a cross-sectional view for explaining the configuration of the heating section main body shown in FIG. 3. FIG. 4 is a block diagram for explaining the configuration of the ink warming mechanism shown in FIG. 3. FIG. 4 is a flowchart for explaining an example of a method for controlling the heater shown in FIG. 3. FIG. 4 is a graph for explaining an example of a method of controlling the heater shown in FIG. 3. FIG. 7 is a diagram for explaining an example of a table stored in the heater control unit shown in FIG. 6. FIG. 7 is a flowchart for explaining an example of a heater control method according to another embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the drawings.

(Schematic configuration of inkjet printer)
FIG. 1 is a perspective view of an inkjet printer 1 according to an embodiment of the invention. FIG. 2 is a schematic diagram for explaining the configuration of the inkjet printer 1 shown in FIG. 1. As shown in FIG. FIG. 3 is a partial perspective view of the peripheral portion of the carriage 4 shown in FIG. 2. As shown in FIG. FIG. 4 is a sectional view of the pressure adjustment mechanism 11 shown in FIG. 3.

The inkjet printer 1 of this embodiment (hereinafter referred to as "printer 1") is, for example, a business inkjet printer, and prints on a print medium 2. The printing medium 2 is, for example, printing paper, cloth, a resin film, or the like. The printer 1 includes an inkjet head 3 (hereinafter referred to as the "head 3") that discharges ink toward a print medium 2, a carriage 4 on which the head 3 is mounted, and a carriage 4 that moves in the main scanning direction (see FIG. A carriage drive mechanism 5 for moving the carriage 4 in the Y direction), a guide rail 6 for guiding the carriage 4 in the main scanning direction, and a plurality of ink tanks 7 containing ink to be supplied to the head 3. . In the following explanation, the main scanning direction (Y direction) is referred to as the "left-right direction", and the vertical direction (Z direction in Figure 1, etc.) and the sub-scanning direction (X direction in Figure 1, etc.) perpendicular to the main scanning direction is referred to as " "Anteroposterior direction".

The head 3 discharges ultraviolet curing ink (UV ink). Further, the head 3 discharges ink downward. A nozzle surface (ink ejection surface) on which a plurality of nozzles are arranged is formed on the lower surface of the head 3 . The head 3 includes a piezoelectric element that ejects ink from a nozzle. A platen 8 is arranged below the head 3. The print medium 2 for printing is placed on the platen 8 . The print medium 2 placed on the platen 8 is conveyed in the front-rear direction by a medium feeding mechanism (not shown). The carriage drive mechanism 5 includes, for example, two pulleys, a belt that spans the two pulleys and is partially fixed to the carriage 4, and a motor that rotates the pulleys.

The printer 1 also includes a temperature sensor 10 (hereinafter referred to as "external temperature sensor 10") for detecting an external temperature Ta of the printer 1, and a pressure sensor 10 for adjusting the pressure of ink supplied to the head 3. It includes an adjustment mechanism 11 and an ink warming mechanism 12 for warming the ink supplied to the head 3. External temperature sensor 10 is, for example, a thermistor. The external temperature sensor 10 is arranged on the operation panel 13 of the printer 1 (see FIG. 1). The external temperature sensor 10 of this embodiment is a second temperature sensor.

The ink warming mechanism 12 is disposed between the pressure adjustment mechanism 11 and the head 3 on the ink supply path to the head 3 . Ink is supplied to the ink warming mechanism 12 from the pressure adjustment mechanism 11 . The pressure adjustment mechanism 11 accommodates ink to be supplied to the ink warming mechanism 12 . Specifically, the pressure adjustment mechanism 11 accommodates ink to be supplied to an ink flow path 21a formed inside the heating section main body 21, which will be described later. The head 3 discharges ink supplied from the ink warming mechanism 12. The pressure adjustment mechanism 11 and the ink warming mechanism 12 are mounted on the carriage 4.

Ink is supplied to the pressure adjustment mechanism 11 from the ink tank 7. Specifically, the ink tank 7 is arranged above the pressure adjustment mechanism 11, and ink is supplied from the ink tank 7 to the pressure adjustment mechanism 11 due to the water head difference. The pressure adjustment mechanism 11 is a mechanical pressure damper, and mechanically adjusts the pressure of ink supplied to the head 3 without using a pressure adjustment pump. Further, the pressure adjustment mechanism 11 adjusts the pressure of ink supplied to the head 3 so that the ink chamber formed inside the head 3 has a negative pressure.

An ink flow path 15 through which ink flows is formed inside the pressure adjustment mechanism 11 . Specifically, an ink flow path 15 is formed inside the main body frame 14 of the pressure adjustment mechanism 11 . In this embodiment, two ink flow paths 15 are formed inside the main body frame 14. A part of the ink flow path 15 serves as a pressure chamber 16 for making the internal pressure of the head 3 negative pressure. The ink flow path 15 of this embodiment is a second ink flow path.

The pressure adjustment mechanism 11 includes a thin flexible membrane 17 that forms part of the wall surface of the pressure chamber 16 . The pressure adjustment mechanism 11 also includes a sealing valve 18 that is biased toward a closed position that stops ink from flowing into the pressure chamber 16, and an open valve 19 that is biased away from the sealing valve 18. It is equipped with The release valve 19 is fixed to a flexible membrane 17, and the flexible membrane 17 is biased in a direction that increases the volume of the pressure chamber 16. The release valve 19 pushes the sealing valve 18 towards an open position which allows ink to flow into the pressure chamber 16 when the amount of ink in the pressure chamber 16 decreases. When the sealing valve 18 moves to the open position, ink flows into the pressure chamber 16.

The pressure adjustment mechanism 11 is formed in the shape of a flat rectangular parallelepiped with a thin thickness in the left-right direction. The pressure adjustment mechanism 11 is attached to the ink warming mechanism 12. In this embodiment, two pressure adjustment mechanisms 11 are attached to one ink warming mechanism 12. The two pressure adjustment mechanisms 11 attached to one ink warming mechanism 12 are arranged adjacent to each other in the left and right direction.

(Configuration of ink heating mechanism)
FIG. 5 is a cross-sectional view for explaining the configuration of the heating section main body 21 shown in FIG. 3. As shown in FIG. FIG. 6 is a block diagram for explaining the configuration of the ink warming mechanism 12 shown in FIG. 3. As shown in FIG.

The ink warming mechanism 12 is an extra-head ink warming device disposed outside the head 3 . The ink warming mechanism 12 functions to reduce the viscosity of the ink supplied to the head 3 by warming the ink supplied to the head 3. The ink warming mechanism 12 is arranged above the head 3. The ink heating mechanism 12 includes a heating unit main body 21 formed in a block shape, a heater 22 attached to the heating unit main body 21, and a temperature sensor 23 (hereinafter referred to as “warming unit main body 21”) attached to the heating unit main body 21. temperature sensor 23).

The heater 22 is a sheet heater formed in a sheet shape. Further, the heater 22 is a print heater that includes a conductive pattern and an insulating sheet (insulating film) that sandwiches the conductive pattern from both sides. In this embodiment, one heater 22 is attached to the heating section main body 21. The heater 22 heats the heating section main body 21. The heating section temperature sensor 23 is, for example, a thermistor. The heating section temperature sensor 23 detects the temperature of the heating section main body 21 . The ink warming mechanism 12 also includes a heater control section 24 that controls the heater 22 based on the detection result of the heating section temperature sensor 23. The heater 22 and the heating section temperature sensor 23 are electrically connected to the heater control section 24 . Furthermore, the external temperature sensor 10 is electrically connected to the heater control section 24 .

The heating unit main body 21 is formed into a generally rectangular parallelepiped shape as a whole. Further, the heating section main body 21 is made of a metal material with high thermal conductivity. For example, the heating section main body 21 is made of an aluminum alloy. An ink flow path 21a through which ink flows is formed inside the heating section main body 21. Specifically, two ink flow paths 21a through which ink is supplied to the head 3 from one pressure adjustment mechanism 11 of the two pressure adjustment mechanisms 11 attached to the ink heating mechanism 12, and the other A total of four ink channels 21a, including two ink channels 21a through which ink supplied from the pressure adjustment mechanism 11 to the head 3 flows, are formed inside the heating section main body 21. In this embodiment, the ink flow path 21a constitutes an ink passage section through which ink passes.

The ink flow path 21a is formed in a flow path forming portion 21b that constitutes the lower end portion of the heating section main body 21. The upper side of the flow path forming part 21b is a housing part 21c in which a lower part of the pressure adjustment mechanism 11 is housed. That is, the heating section main body 21 is formed with an accommodating section 21c in which a part of the pressure adjustment mechanism 11 is accommodated, and a part of the pressure regulation mechanism 11 is accommodated in the heating section main body 21. The accommodating portion 21c of this embodiment is a pressure adjustment mechanism accommodating portion.

As described above, the upper side of the flow path forming portion 21b serves as the accommodating portion 21c, and the pressure adjustment mechanism 11 is arranged above the ink flow path 21a. The housing portion 21c is formed in a box shape with an open top. An ink inflow portion 21d through which ink flows from the pressure adjustment mechanism 11 toward the ink flow path 21a is formed at the upper end of the flow path forming portion 21b. An ink outflow portion 21e from which ink flows out from the ink flow path 21a toward the head 3 is formed at the lower end of the flow path forming portion 21b.

The heater 22 is attached to the left and right side surfaces and the front surface of the heating section main body 21. The upper end of the heater 22 is disposed below the upper end of the housing section 21c (that is, the upper end of the heating section main body 21). Further, the upper end of the heater 22 is arranged above the lower end of the accommodating portion 21c (that is, the upper end of the flow path forming portion 21b). The lower end of the heater 22 is disposed below the lower end of the accommodating portion 21c (that is, the upper end of the flow path forming portion 21b). Further, the lower end of the heater 22 is arranged above the lower end of the flow path forming portion 21b (that is, the lower end of the heating section main body 21). A portion of the heating section main body 21 to which the heater 22 is attached is a heater attachment section 21f. That is, the heating section main body 21 is formed with a heater attachment section 21f to which the heater 22 is attached.

The heating section temperature sensor 23 is attached to the front surface of the heating section main body 21. For example, the heating section temperature sensor 23 is fixed to the front surface of the heating section main body 21 with a screw (not shown). The heating section temperature sensor 23 is arranged above the heater 22 . That is, the heating section temperature sensor 23 is attached to the heating section main body 21 above the heater attachment section 21f. A portion of the heating section main body 21 to which the heating section temperature sensor 23 is attached is a sensor attachment section 21g. That is, the heating section main body 21 is formed with a sensor attachment section 21g to which the heating section temperature sensor 23 is attached.

The sensor attachment portion 21g projects upward from the heater attachment portion 21f. That is, a portion of the heating section main body 21 that extends upward from the heater attachment section 21f is a sensor attachment section 21g, and the sensor attachment section 21g is arranged above the heater attachment section 21f. The lower end of the sensor attachment part 21g is connected to the upper end of the heater attachment part 21f. Further, the heating section temperature sensor 23 is attached to the upper end portion of the front surface of the accommodating section 21c. That is, the upper end portion of the housing portion 21c is a sensor attachment portion 21g, and the heating section temperature sensor 23 is attached to the front surface of the sensor attachment portion 21g. The sensor attachment portion 21g constitutes a part of the housing portion 21c. Note that the heating section temperature sensor 23 may be attached to the left and right side surfaces of the sensor attachment section 21g (that is, the upper end portions of the left and right side surfaces of the accommodating section 21c).

Further, the sensor mounting portion 21g is arranged at approximately the same position as the pressure chamber 16 of the pressure adjustment mechanism 11 in the vertical direction. That is, the sensor mounting portion 21g is arranged beside the pressure chamber 16. Furthermore, the sensor attachment portion 21g is close to the outer surface of the portion of the pressure adjustment mechanism 11 where the ink flow path 15 is formed. Specifically, the sensor attachment portion 21g is close to the outer surface of the portion of the main body frame 14 where the ink flow path 15 is formed. More specifically, the sensor attachment portion 21g is in contact with the outer surface of the portion of the main body frame 14 where the ink flow path 15 is formed. Note that a slight gap may be formed between the outer surface of the portion of the main body frame 14 where the ink flow path 15 is formed and the sensor mounting portion 21g.

The pressure adjustment mechanism 11 is arranged above the ink flow path 21a, and ink flows downward into the ink flow path 21a. That is, in this embodiment, assuming that the flow direction (downward) of ink flowing into the ink flow path 21a is the ink flow direction, the sensor mounting portion 21g is arranged on the upstream side (upper side) of the heater pasting portion 21f in the ink flow direction. has been done. That is, the sensor attachment part 21g is provided to protrude upstream (upper side) of the heater attachment part 21f in the ink flow direction, and the heating section temperature sensor 23 is provided upstream of the heater attachment part 21f in the ink flow direction. It is attached to the heating section main body 21.

(Heater control method)
FIG. 7 is a flowchart for explaining an example of a method for controlling the heater 22 shown in FIG. FIG. 8 is a graph for explaining an example of a method of controlling the heater 22 shown in FIG. FIG. 9 is a diagram for explaining an example of a table stored in the heater control unit 24 shown in FIG. 6.

The heater control unit 24 controls the heating unit temperature sensor so that the temperature of the heating unit body 21 (more specifically, the temperature of the heating unit body 21 when printing the print medium 2) becomes a predetermined reference temperature Tb. The heater 22 is controlled based on the detection result of 23 (that is, based on the temperature of the heating section main body 21). Furthermore, before ink is ejected from the head 3, the heater control unit 24 initializes the reference temperature Tb based on the detection result of the external temperature sensor 10 (that is, based on the external temperature Ta of the printer 1). Furthermore, the heater control unit 24 measures the amount of temperature decrease in the heating unit main body 21 due to the influence of the ink flowing into the ink flow path 21a, using the heating unit temperature sensor 23 after the ejection of ink from the head 3 is started. The reference temperature Tb is calculated based on the detection result, and the reference temperature Tb is updated based on the calculated amount of temperature decrease of the heating section main body 21.

Specifically, the heater control unit 24 controls the heater 22 as follows. Note that, as an example of a method for controlling the heater 22, a method for controlling the heater 22 when the optimum temperature of ink supplied to the head 3 is about 45° C. will be described below.

As shown in FIG. 7, for example, when a print command for the print medium 2 is input to the control unit of the printer 1, the heater control unit 24 detects the external temperature Ta of the printer 1 using the external temperature sensor 10 (step S1 ). Thereafter, the heater control unit 24 initializes the reference temperature Tb based on the detection result of the external temperature sensor 10 in step S1 (step S2). More specifically, in step S2, the heater control unit 24 initializes the reference temperature Tb based on the optimum temperature of the ink supplied to the head 3 and the detection result of the external temperature sensor 10 in step S1.

In this embodiment, the heater control unit 24 includes a plurality of external temperatures Ta that can be detected by the external temperature sensor 10 and a reference temperature Tb that is associated in advance with each of the plurality of external temperatures Ta that can be detected by the external temperature sensor 10. is stored in a table. For example, the table shown in FIG. 9 is stored in the heater control unit 24, and the heater control unit 24 initializes the reference temperature Tb, which is associated with the external temperature Ta detected in step S1, in step S2.

For example, when the external temperature Ta of the printer 1 detected in step S1 is 15° C., the heater control unit 24 initially sets the reference temperature Tb to 52° C. in step S2 (see FIG. 8(A)). . Further, for example, when the external temperature Ta of the printer 1 detected in step S1 is 25°C, the heater control unit 24 initializes the reference temperature Tb to 48°C in step S2 (see FIG. 8(B)). If the external temperature Ta of the printer 1 detected in step S1 is 35° C., the heater control unit 24 initializes the reference temperature Tb to 44° C. in step S2 (see FIG. 8C). ).

After that, the heater control section 24 supplies power to the heater 22 to heat the heating section main body 21 (step S3). When the temperature of the heating unit main body 21 heated by the heater 22 reaches the initially set reference temperature Tb (see FIG. 8, step S4), ejection of ink from the head 3 is started (step S5). That is, ink begins to be ejected toward the print medium 2. When the ejection of ink from the head 3 is started and the supply of ink from the ink warming mechanism 12 to the head 3 is started, the ink in the ink flow path 21a flows from the pressure adjustment mechanism 11 to the ink flow path 21a. Since the ink flows into the ink flow path 21a, the temperature of the heating section main body 21 may decrease due to the influence of the ink flowing into the ink flow path 21a (see FIG. 8).

When a predetermined period of time has elapsed after the start of ink ejection from the head 3, the heater control unit 24 detects the temperature of the heating unit main body 21 using the heating unit temperature sensor 23 (step S6). Furthermore, the heater control unit 24 calculates the amount of temperature decrease of the heating unit main body 21 based on the detection result of the heating unit temperature sensor 23 in step S6 (step S7). That is, in step S7, the heater control unit 24 calculates the amount of temperature decrease of the heating unit main body 21 due to the influence of the ink flowing into the ink flow path 21a based on the detection result of the heating unit temperature sensor 23. Specifically, the heater control unit 24 calculates the value per unit time obtained by subtracting the temperature of the heating unit main body 21 detected in step S6 from the reference temperature Tb by the elapsed time from the start of ink ejection to step S6. The amount of temperature decrease is calculated in step S7.

Thereafter, the heater control unit 24 updates the reference temperature Tb based on the amount of temperature decrease of the heating unit main body 21 calculated in step S7 (step S8). For example, if the amount of temperature decrease calculated in step S7 is large, the heater control unit 24 updates the reference temperature Tb to a temperature higher than the reference temperature Tb set in step S2 (see FIG. (See broken lines in (A) to (C)).

For example, if the external temperature Ta of the printer 1 detected in step S1 is 15° C. or 25° C. and the amount of temperature decrease calculated in step S7 is small, the heater control unit 24 The reference temperature Tb is updated to a temperature lower than the set reference temperature Tb (see solid lines in FIGS. 8(A) and 8(B)), and the external temperature Ta of the printer 1 detected in step S1 is 35. ℃, and if the amount of temperature decrease calculated in step S7 is small, the heater control unit 24 sets the reference temperature Tb to be approximately the same as the reference temperature Tb set in step S2. Update is performed (see solid line in FIG. 8(C)).

Further, for example, if the external temperature Ta of the printer 1 detected in step S1 is 15° C. or 25° C., and the amount of temperature decrease calculated in step S7 is neither large nor small, the heater control unit 24 , the reference temperature Tb is updated to a temperature similar to the reference temperature Tb set in step S2 (see dashed lines in FIGS. 8A and 8B), and the printer 1 detected in step S1 is updated. If the external temperature Ta is 35° C. and the amount of temperature decrease calculated in step S7 is neither large nor small, the heater control unit 24 sets the temperature slightly higher than the reference temperature Tb set in step S2. The reference temperature Tb is updated by setting the reference temperature Tb to be the reference temperature Tb (see the dashed line in FIG. 8(C)).

Thereafter, the heater control unit 24 controls the heater 22 based on the reference temperature Tb updated in step S8 until printing on the print medium 2 is completed (steps S9 and S10). Specifically, the heater control unit 24 controls the heater 22 so that the temperature detected by the heating unit temperature sensor 23 becomes the reference temperature Tb updated in step S8 until printing of the print medium 2 is completed. Control.

(Main effects of this form)
As explained above, in this embodiment, the heating section temperature sensor 23 is attached to the sensor attaching part 21g that protrudes above the heater attaching part 21f to which the heater 22 is attached. Therefore, in this embodiment, the heat of the heater 22 is less likely to be directly transmitted to the heating section temperature sensor 23, and the influence of the heater 22 on the detection result of the heating section temperature sensor 23 can be reduced. Therefore, in this embodiment, the temperature of the ink passing through the ink flow path 21a can be appropriately detected by the heating part temperature sensor 23 via the heating part main body 21, and as a result, the temperature of the heating part Based on the appropriate detection result of the sensor 23, it becomes possible to appropriately control the heater 22 so that variations in the temperature of the ink supplied to the head 3 are suppressed. Therefore, in this embodiment, it is possible to suppress variations in the viscosity of the ink supplied from the ink warming mechanism 12 to the head 3.

In addition, in this embodiment, since the heating section temperature sensor 23 is attached to the sensor attachment section 21g that protrudes upstream in the ink flow direction of the heater attachment section 21f, the temperature of the ink before being warmed by the heater 22 is increased. This is more likely to be reflected in the detection results of the hot part temperature sensor 23. Therefore, in this embodiment, the heater 22 can be controlled based on the detection result of the heating section temperature sensor 23, reflecting the external temperature Ta of the printer 1. As a result, in this embodiment, it is possible to effectively suppress variations in the viscosity of the ink supplied from the ink warming mechanism 12 to the head 3.

In particular, in this embodiment, the sensor mounting portion 21g is close to the outer surface of the portion of the pressure adjustment mechanism 11 where the ink flow path 15 is formed, so that the temperature of the ink before being warmed by the heater 22 is lower than that of the heating portion. This is more likely to be reflected in the detection results of the temperature sensor 23. Therefore, in this embodiment, it is possible to control the heater 22 that more closely reflects the external temperature Ta of the printer 1 based on the detection result of the heating section temperature sensor 23, and as a result, the ink heating mechanism 12 is able to It becomes possible to more effectively suppress variations in the viscosity of the supplied ink.

In this embodiment, the sensor attachment portion 21g protrudes above the heater attachment portion 21f. Therefore, in this embodiment, for example, it is not necessary to cut out a part of the heater 22 attached to the heater attachment part 21f and to attach the heating section temperature sensor 23 to the cutout part of the heater 22. Therefore, in this embodiment, it becomes possible to attach the heater 22 to the entire heater attachment section 21f, and as a result, it becomes possible to efficiently heat the heating section main body 21 by the heater 22.

In this embodiment, the sensor attachment part 21g constitutes a part of the accommodating part 21c in which a part of the pressure adjustment mechanism 11 is accommodated. Therefore, in this embodiment, even if the sensor attachment portion 21g is formed in the heating section main body 21, the configuration of the heating section main body 21 can be simplified.

In this embodiment, the heater control unit 24 calculates the amount of temperature decrease of the heating unit main body 21 due to the influence of ink flowing into the ink flow path 21a based on the detection result of the heating unit temperature sensor 23, and The reference temperature Tb is updated based on the amount of temperature decrease of the section body 21. Specifically, when it is estimated that the amount of temperature decrease in the heating section main body 21 is large and the amount of ink flowing into the ink flow path 21a per unit time is large, the heater control section 24 controls the initial When the set reference temperature Tb is updated to a higher temperature and it is estimated that the amount of temperature decrease in the heating section main body 21 is small and the amount of ink flowing into the ink flow path 21a per unit time is small, The initially set reference temperature Tb is updated to a lower temperature, or the initially set reference temperature Tb is updated to a similar temperature.

Therefore, in this embodiment, when the amount of ink supplied from the ink heating mechanism 12 to the head 3 per unit time increases, and the passage time of the ink passing through the ink flow path 21a becomes short, the temperature increases. It becomes possible to control the heater 22 based on the reference temperature Tb updated in When the amount of ink supplied from the heating mechanism 12 to the head 3 per unit time decreases, and the time taken for the ink to pass through the ink flow path 21a becomes longer, the temperature is set to the same level as the initially set reference temperature Tb. The heater 22 is controlled based on the reference temperature Tb that has been updated to the temperature or a lower temperature and the detection result of the heating section temperature sensor 23 to prevent the ink supplied to the head 3 from being heated above a predetermined temperature. It becomes possible to do so. Therefore, in this embodiment, it is possible to effectively suppress variations in the viscosity of the ink supplied from the ink warming mechanism 12 to the head 3.

In this embodiment, if the external temperature Ta of the printer 1 is high and the temperature of the ink flowing into the ink flow path 21a is high, even if the amount of heat added to the ink passing through the ink flow path 21a is small, it will not be supplied to the head 3. On the other hand, if the external temperature Ta of the printer 1 is low and the temperature of the ink flowing into the ink flow path 21a is low, the ink passing through the ink flow path 21a may be heated to a predetermined temperature. If the amount of heat applied is not large, it will be difficult to heat the ink supplied to the head 3 to a predetermined temperature. The reference temperature Tb is initially set based on the detection result. Specifically, when the external temperature Ta of the printer 1 is high, the heater control unit 24 sets the reference temperature Tb to a low temperature based on the detection result of the external temperature sensor 10, so that the external temperature Ta of the printer 1 is low. In this case, the reference temperature Tb is set to a high temperature based on the detection result of the external temperature sensor 10.

Therefore, in this embodiment, when the external temperature Ta of the printer 1 is high, the heater 22 is controlled based on the reference temperature Tb, which is initially set to a low temperature, and the detection result of the heating section temperature sensor 23, and the head 3 In addition, when the external temperature Ta of the printer 1 is low, the reference temperature Tb, which is initially set to a high temperature, and the detection by the heating section temperature sensor 23 can be heated to a predetermined temperature. Based on the results, it becomes possible to control the heater 22 to heat the ink supplied to the head 3 to a predetermined temperature. Therefore, in this embodiment, it is possible to heat the ink supplied to the head 3 to a predetermined temperature regardless of the external temperature Ta of the printer 1, and as a result, regardless of the external temperature Ta of the printer 1, the ink It becomes possible to suppress variations in the viscosity of the ink supplied from the heating mechanism 12 to the head 3.

(Other embodiments)
Although the embodiment described above is an example of a preferred embodiment of the present invention, it is not limited thereto, and various modifications can be made without changing the gist of the present invention.

In the above-described embodiment, as shown in FIG. 10, after updating the reference temperature Tb in step S8, the heater control unit 24 controls the heater 22 based on the reference temperature Tb updated in step S8 until a predetermined period of time has elapsed. may be controlled (steps S9, S11). For example, the heater control unit 24 may control the heater 22 based on the reference temperature Tb updated in step S8 until the print operation of one scan by the head 3 is completed. In this case, for example, after updating the reference temperature Tb in step S8, when a predetermined period of time has elapsed, the process proceeds to step S10, and if printing on the print medium 2 has not been completed, the process returns to step S6.

In step S7 after step S10, the heater control unit 24, for example, sets a predetermined value by subtracting the temperature of the heating unit body 21 detected in the current step S6 from the reference temperature Tb updated in the previous step S8. Calculate the amount of temperature decrease per unit time divided by the elapsed time. In this case, even if the amount of ink supplied from the ink warming mechanism 12 to the head 3 per unit time varies while printing the print medium 2, the ink is supplied from the ink warming mechanism 12 to the head 3. It becomes possible to suppress variations in ink viscosity.

In the embodiment described above, the heating section temperature sensor 23 may be attached inside the sensor attachment section 21g (that is, inside the upper end side portion of the housing section 21c). Furthermore, in the embodiment described above, the external temperature sensor 10 may be attached to the body frame of the printer 1 or may be mounted on the carriage 4. In addition, in the above-described embodiment, if the external temperature Ta of the printer 1 can be appropriately detected by the heating part temperature sensor 23, the external temperature Ta of the printer 1 can be detected by the heating part temperature sensor 23. good. That is, the temperature sensor that detects the external temperature Ta of the printer 1 and the temperature sensor that detects the temperature of the heating section main body 21 may be a common heating section temperature sensor 23.

In the embodiment described above, the heater control unit 24 initializes the reference temperature Tb based on the external temperature Ta of the printer 1 detected by the external temperature sensor 10; The reference temperature Tb may be initialized according to the specifications of the ink to be used (specifically, according to the optimum temperature of the ink supplied to the head 3). Furthermore, in the above-described embodiment, the heater control unit 24 does not need to update the reference temperature Tb.

In the embodiment described above, the entire pressure adjustment mechanism 11 may be housed in the housing portion 21c. Further, in the above-described embodiment, a large gap may be formed between the outer surface of the portion of the main body frame 14 where the ink flow path 15 is formed and the sensor mounting portion 21g. Furthermore, in the embodiment described above, the heater 22 may be a heater other than the seat heater. Further, in the above-described embodiment, the number of ink channels 21a formed in the heating section main body 21 may be three or less, or five or more.

In the embodiment described above, an ink reservoir (ink chamber) in which ink accumulates may be formed inside the heating section main body 21 instead of the ink flow path 21a. In this case, the ink pool constitutes an ink passage portion through which ink passes. Further, in the above-described embodiment, an ink reservoir may be formed inside the heating section main body 21 in addition to the ink flow path 21a. In this case, the ink passage 21a and the ink reservoir constitute an ink passage section through which ink passes.

In the embodiment described above, the printer 1 may include a sub-tank in which ink to be supplied to the head 3 is stored instead of the pressure adjustment mechanism 11. Further, in the above-described embodiment, the printer 1 may include, instead of the platen 8, a table on which the print medium 2 is placed and a table drive mechanism that moves the table in the front-back direction. Furthermore, in the embodiment described above, the printer 1 may be a 3D printer that forms a three-dimensional object. Further, in the above-described embodiment, the ink ejected by the head 3 may be a water-based ink or a solvent ink.

1 Printer (inkjet printer)
3 head (inkjet head)
10 External temperature sensor (second temperature sensor)
11 Pressure adjustment mechanism 12 Ink warming mechanism 15 Ink channel (second ink channel)
21 Heating section main body 21a Ink flow path (ink passage section)
21c Housing part (pressure adjustment mechanism housing part)
21f Heater attachment part 21g Sensor attachment part 22 Heater 23 Heating part temperature sensor (temperature sensor)
24 Heater control section

Claims (6)

An inkjet head that discharges ink, and an ink heating mechanism that warms the ink supplied to the inkjet head,
The ink heating mechanism includes: a block-shaped heating section main body in which an ink passage section through which ink passes is formed; a heater attached to the heating section main body and heating the heating section main body; comprising a temperature sensor attached to the heating unit main body to detect the temperature of the heating unit main body, and a heater control unit controlling the heater based on the detection result of the temperature sensor,
The ink passage portion includes at least one of an ink channel through which ink flows and an ink reservoir in which ink accumulates;
The heating unit main body is formed with a heater attachment part to which the heater is attached, and a sensor attachment part to which the temperature sensor is attached,
If the flow direction of the ink flowing into the ink passage section is defined as the ink flow direction,
The inkjet printer is characterized in that the sensor attachment section is provided to protrude upstream of the heater attachment section in the ink flow direction. Ink supplied to the ink passage section is accommodated, and a pressure adjustment mechanism is provided that adjusts the pressure of the ink supplied to the inkjet head,
At least a portion of the pressure adjustment mechanism is housed in the heating unit main body,
A second ink flow path through which ink flows is formed inside the pressure adjustment mechanism,
2. The inkjet printer according to claim 1, wherein the sensor mounting portion is close to an outer surface of a portion of the pressure adjustment mechanism where the second ink flow path is formed. A pressure adjustment mechanism accommodating part in which a part of the pressure adjustment mechanism is housed is formed in the heating unit main body,
3. The inkjet printer according to claim 2, wherein the sensor mounting section constitutes a part of the pressure adjustment mechanism housing section. The pressure adjustment mechanism is arranged above the ink passage section,
4. The inkjet printer according to claim 2, wherein the sensor attachment section is arranged above the heater attachment section. The heater control unit controls the heater based on the detection result of the temperature sensor so that the temperature of the heating unit main body becomes a predetermined reference temperature, and also controls the heater based on the detection result of the temperature sensor so that the temperature of the heating unit main body becomes a predetermined reference temperature. The amount of temperature decrease of the heating section main body is calculated based on the detection result of the temperature sensor after the ejection of ink from the inkjet head is started, and the temperature reduction amount of the heating section main body is calculated based on the calculated amount of temperature reduction of the heating section main body. 5. The inkjet printer according to claim 1, wherein the reference temperature is updated. comprising a second temperature sensor for detecting an external temperature of the inkjet printer,
6. The inkjet printer according to claim 5, wherein the heater control section initializes the reference temperature based on a detection result of the second temperature sensor before ink is ejected from the inkjet head.

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