JP2020152038A - Liquid discharge device - Google Patents

Abstract

To provide means of inhibiting the conveyance speed of a conveyor belt from being changed over time through heating by a heater.SOLUTION: A printing device 10 comprises: a print head 24 to discharge an ink to a sheet conveyed in a conveyance direction; a heater 26 positioned at the downstream of the print head 24 in the conveyance direction; a conveyor belt 25 facing the print head 24; a conveyor belt 27 facing the heater 26; and a controller. The controller 130 determines a correction value Vt to correct a rotational speed V of a pulley 93 and drive the pulley 93 on the basis of the determined correction value Vt.SELECTED DRAWING: Figure 5

Description

The present invention relates to a printing apparatus including a printing unit, a heater, and a transport belt.

As an example of the printing apparatus, there is known an image forming apparatus in which printing is performed by adhering ink discharged from a head to a sheet. This image forming apparatus has a transport belt that supports the seat at a position facing the head. The conveyor belt has an endless belt hung between two rollers (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2007-276970

In the image forming apparatus, for example, when the sheet needs to be heated for the ink to be fixed to the sheet, a heater is provided downstream of the head in the transport direction. The ink discharged from the head to the sheet is heated by the heater and adheres to the sheet. Further, even in the electrophotographic image forming apparatus, the toner adhering to the sheet is heated by the heater and adheres to the sheet. It is desirable that the sheet to which the printing material such as ink or toner is attached is supported at a position facing the heater.

For example, if a transport belt is provided at a position facing the heater, the transport belt is heated by the heater. As a result, there is a problem that the transfer speed of the sheet by the transfer belt changes due to the expansion of the roller around which the endless belt is wound. When one sheet is transported by both the transport belt facing the printing unit and the transport belt facing the heater, when the transport speed of the transport belt facing the heater changes, printing is performed via the sheet. The transport speed of the transport belt facing the portion is also affected. If the transport speed of the transport belt facing the printing unit changes, problems such as deterioration of print image quality may occur.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a means for suppressing a time-dependent change in the transport speed of a transport belt due to heating of a heater.

The printing apparatus according to the present invention is located in a printing unit for printing by adhering a printing material to a sheet transported in the transport direction and downstream of the printing section in the transport direction, and is transported in the transport direction. A heater that heats the sheet and at least one of the printing materials adhering to the sheet, a first transport belt that faces the printing unit and transports the sheet in the transport direction, a rotating body, and the above. It is provided with a second transport belt that faces the heater and that transports the sheet in the transport direction by transmitting the rotation of the rotating body and moving at a transport speed, and a control unit. The control unit determines a correction value for correcting the rotation speed of the rotating body with respect to the time-dependent change of the transfer speed of the second transport belt due to the heating of the heater, and based on the determined correction value, the above Drive the rotating body.

According to the above configuration, the change with time of the transport speed of the second transport belt due to the heating of the heater is suppressed.

According to the present invention, the time-dependent change of the transport speed of the transport belt due to the heating of the heater is suppressed. As a result, the transport speed of the sheet transported facing the printing unit and the heater becomes stable.

FIG. 1 is a perspective view of the front wall 31 side of the printing apparatus 10. FIG. 2 is a schematic view of a cross section of II-II of FIG. FIG. 3 is a schematic view of a cross section III-III of FIG. FIG. 4 is a block diagram including the controller 130. FIG. 5 is a flowchart showing the operation of the printing device 10. FIG. 6 is a flowchart showing a transport operation. FIG. 7 is a schematic view showing a transport belt 27 and the like according to a modified example.

Hereinafter, the printing apparatus 10 according to the embodiment of the present invention will be described. It is needless to say that the embodiments described below are merely examples of the present invention, and the embodiments can be appropriately changed without changing the gist of the present invention. Further, in the following description, the direction from the start point to the end point of the arrow is expressed as the direction, and the traffic on the line connecting the start point and the end point of the arrow is expressed as the direction. Further, in the following description, the vertical direction 7 is defined based on the state in which the printing device 10 is usably installed (the state in FIG. 1), and the side where the discharge port 13 is provided is the front side (front side). The front-rear direction 8 is defined as, and the left-right direction 9 is defined when the printing device 10 is viewed from the front side (front side).

[Appearance configuration of printing device 10]
As shown in FIG. 1, the printing apparatus 10 records an image on roll paper 11 (see FIG. 2) or the like by an inkjet recording method. The housing 14 has a substantially rectangular parallelepiped shape in which a discharge port 13 is formed on a front wall 31. The discharge port 13 is located on the right side of the front wall 31. The housing 14 has a size that allows it to be placed on a table. That is, the printing device 10 is suitable for being placed on a table and used. Of course, the printing device 10 may be used by being placed on the floor surface.

The operation panel 17 is located on the left side of the discharge port 13 on the front wall 31. The operation panel 17 has, for example, a display, input keys, and the like. The user inputs input for operating the printing device 10 and confirming various settings on the operation panel 17.

A cover 16 is provided below the operation panel 17. By opening the cover 16, the internal space of the housing 14 is exposed. A tank 70 (see FIG. 2), which will be described later, is located behind the cover 16. The cover 16 in the closed state is a part of the front wall 31 of the housing 14.

[Internal configuration of printing device 10]
As shown in FIG. 3, a partition wall 71 is provided in the internal space of the housing 14. The partition wall 71 is a wall that extends in the vertical direction 7 and the front-rear direction 8. In other words, the partition wall 71 extends in the vertical direction 7 and the front-rear direction 8. As shown in FIG. 3, the upper end of the partition wall 71 is connected to the upper wall 33 of the housing 14, and the lower end of the partition wall 71 is connected to the lower wall 34 of the housing 14. The front end of the partition wall 71 is connected to the front wall 31 of the housing 14, and the rear end of the partition wall 71 is connected to the rear wall 32 of the housing 14.

The internal space of the housing 14 is composed of a first space 81 and a second space 82. The first space 81 is a portion of the internal space of the housing 14 to the right of the partition wall 71. The second space 82 is a portion of the internal space of the housing 14 on the left side of the partition wall 71. That is, the partition wall 71 is located between the first space 81 and the second space 82. The partition wall 71 has an opening 72. The first space 81 and the second space 82 are connected through the opening 72.

As shown in FIG. 2, a transport path 22 is formed in the first space 81. In the first space 81, roll paper 11, feeding rollers 20, 21, first transport roller pair 54, second transport roller pair 55, transport belts 25, 27, heater 26, and temperature sensor 44 are arranged. .. As shown in FIGS. 2 and 3, a tank 70, a cap 73, a control board 74, a power supply circuit 75, and a wiper 101 are arranged in the second space 82.

The print head 24 (an example of a printing unit) includes a carriage 241 and a discharge module 242 mounted on the carriage 241. The carriage 241 can move in the left-right direction 9. Therefore, the print head 24 can be located in either the first space 81 or the second space 82.

As shown in FIG. 2, the print head 24 has two ejection modules 242. The two ejection modules 242 are arranged apart from each other in the front-rear direction 8 in the print head 24. In each discharge module 242, a plurality of nozzles 30 are arranged side by side in the left-right direction 9.

As shown in FIG. 2, the first space 81 has a sheet accommodating space 15 capable of accommodating the roll paper 11. The seat accommodating space 15 is formed in the rear part of the first space 81. The seat accommodating space 15 is a space defined by the partition wall 18. In the sheet accommodating space 15, the roll paper 11 is accommodated with the left-right direction 9 as the roll axis direction. The seat accommodating space 15 opens upward at the rear. A gap 29 through which the sheet drawn from the roll paper 11 can pass is formed between the partition wall 18 and the rear wall 32.

The feeding roller 20 is located in the seat accommodating space 15. The feeding roller 21 is located directly above the seat accommodating space 15 in the first space 81. The sheet pulled out rearward from the roll paper 11 winds around the feeding roller 20 and extends upward, and further winds around the feeding roller 21 and extends forward. The uppermost position of the circumferential surface of the feeding roller 21 is equivalent to the discharge port 13 in the vertical direction 7.

As shown in FIG. 2, a transport path 22 is formed over the feed roller 21 and the discharge port 13. The transport path 22 extends substantially linearly. The transport path 22 is a space through which the sheet can pass. Although not shown in detail in each drawing, the transport path 22 is defined by a guide member, a print head 24, transport belts 25, 27, a heater 26, and the like located apart from each other in the vertical direction 7. In the transport path 22, the forward direction is the transport direction.

As shown in FIG. 2, a first transport roller pair 54 is provided upstream of the print head 24 in the transport path 22 in the transport direction. The first transfer roller pair 54 has a first transfer roller 60 and a pinch roller 61. In the transport path 22, a second transport roller pair 55 is provided downstream of the heater 26 in the transport direction. The second transfer roller pair 55 has a second transfer roller 62 and a pinch roller 63. The rotation of the motor (not shown) is transmitted to the first transfer roller 60 and the second transfer roller 62 to rotate. In the first transfer roller pair 54 and the second transfer roller pair 55, the first transfer roller 60 and the second transfer roller 62 rotate in a state where the sheet extending from the roll paper 11 is sandwiched between the rollers constituting the first transfer roller pair 54 and the second transfer roller pair 55. By doing so, the sheet is conveyed in the conveying direction.

The print head 24, the transfer belts 25, 27, and the heater 26 are located in the transfer path 22 between the first transfer roller pair 54 and the second transfer roller pair 55.

The carriage 241 is supported in the internal space of the housing 14 by a pair of guide rails (not shown) arranged at intervals in the front-rear direction 8. Each of the pair of guide rails extends from the first space 81 to the second space 82. The opening 72 is located between the pair of guide rails in the front-rear direction 8. The carriage 241 is connected to a motor (not shown) via a known belt mechanism. As a result, the carriage 241 can move along with the discharge module 242 along the left-right direction 9. As the configuration for moving the carriage 241, a known configuration can be adopted in addition to the belt mechanism.

The transport path 22 extends along the front-rear direction 8 at a position facing the print head 24 in the vertical direction 7. That is, the left-right direction 9 in which the print head 24 moves is orthogonal to the front-rear direction 8 in which the transport path 22 extends. The direction in which the print head 24 moves may intersect the direction in which the transport path 22 extends, and does not necessarily have to be orthogonal to each other.

The print head 24 can be moved to the first position shown by the solid line in FIG. 3 and the second position shown by the broken line in FIG. The print head 24 at the first position is located in the first space 81. The print head 24 at the second position is located in the second space 82. The print head 24 passes through the opening 72 when moving from the first position to the second position and when moving from the second position to the first position. That is, the opening 72 has a size that allows the print head 24 to pass through.

The print head 24 at the first position faces the transport belt 25 across the transport path 22 downstream of the first transport roller pair 54 in the transport direction, and is located above the transport belt 25 and the transport path 22. ing. The print head 24 at the second position is retracted to the left from the transport path 22. The print head 24 at the second position is located above the cap 73 so as to face the cap 73. The arrangement of the two caps 73 corresponds to the arrangement of the two ejection modules 242 of the print head 24 located above.

When the print head 24 is in the first position, ink is ejected from a plurality of nozzles 30 toward the transport path 22 and the transport belt 25 (or the sheet supported by the transport belt 25). When the print head 24 is in the second position, ink (an example of a recording material or a liquid) is ejected from a plurality of nozzles 30 toward the space inside the cap 73.

As shown in FIG. 3, the plurality of nozzles 30 are formed side by side in the left-right direction 9 on the lower surface of the discharge module 242. In FIG. 2, only one row of the plurality of nozzles 30 is shown in each discharge module, but the plurality of nozzles 30 are provided in a plurality of rows in the transport direction in one discharge module 242. When the print head 24 is located at the first position, both ends of the plurality of nozzles 30 in the left-right direction 9 face each other of both ends of the transport path 22 in the left-right direction 9. As shown in FIG. 2, the tank 70 is located in the second space 82 behind the cover 16. Ink is stored in the tank 70. Although not shown, ink is supplied from the tank 70 to the print head 24 through the tube 76.

The ink is a liquid containing pigments, resin fine particles, and the like, and is a so-called latex ink. The ink has a viscosity suitable for uniformly dispersing pigments and resin fine particles. The pigment is the color of the ink. The resin fine particles are for adhering pigments to the sheet, and are, for example, synthetic resins that exceed the glass transition temperature when the heater 26 is heated. The latex ink contains other known components as a composition.

As shown in FIGS. 2 and 3, the transport belt 25 (an example of the first transport belt) is located below the print head 24 at the first position. The transport belt 25 has a pair of pulleys 90, 91 and an endless belt 92 wound around the pulleys 90, 91. The pulleys 90 and 91 can rotate about an axis along the left-right direction 9, respectively. The pulleys 90 and 91 have the same shape including the outer diameter. The pulleys 90 and 91 are made of, for example, synthetic resin or metal. The pulleys 90 and 91 are separated from each other in the front-rear direction 8. An endless belt 92 is wound around the pulleys 90 and 91. The upper surface of the endless belt 92 is parallel to the surface on which each nozzle 30 of the print head 24 opens. The dimension of the endless belt 92 along the left-right direction 9 is larger than the dimension of the roll paper 11 along the left-right direction 9.

The roll paper 11 conveyed through the transfer path 22 is supported on the upper surface of the endless belt 92 of the transfer belt 25 at a position facing the print head 24. The pulley 90 rotates by transmitting a drive from a motor (not shown). The pulley 91 rotates together with the endless bell 92 rotated by the pulley 90. By rotating the endless belt 92, the roll paper 11 supported on the upper surface of the endless belt 92 is conveyed in the conveying direction. Although not shown in each figure, the roll paper 11 may be attracted to the upper surface of the endless belt 92 by applying an electrostatic force or a suction force to the endless belt 92.

As shown in FIG. 3, the print head 24 at the second position is located above the cap 73 so as to face the cap 73.

The cap 73 is connected to the motor 78 via a transmission gear and a cam, and can move in the vertical direction 7 by transmitting a driving force from the motor 78. Specifically, the cap 73 is movable between the cap position shown by the broken line in FIG. 3 and the uncap position shown by the solid line in FIG. The cap 73 at the cap position comes into close contact with the lower surface of the print head 24 from below and covers the plurality of nozzles 30 from below. The state of the cap 73 and the print head 24 at this time is the cap state. The uncap position is below the cap position. The cap 73 at the uncap position is separated from the plurality of nozzles 30. At this time, the plurality of nozzles 30 are exposed without being covered by the cap 73. The state of the cap 73 and the print head 24 at this time is the uncapped state. The upper end of the cap 73 at the uncap position is located below the opening 72.

The opening 72 is not limited to the one in which the top, bottom, front and back are all partitioned by the partition wall 71 (that is, the through hole provided in the partition wall 71). For example, the opening 72 may be a notch cut downward from the upper end of the partition wall 71.

One end of the tube 77 is connected to the cap 73. The tube 77 is a flexible resin tube. The other end of the tube 77 is connected to a waste ink tank (not shown). If the ink is discharged from the nozzle 30 when the cap 73 is located at the cap position, the ink is discharged to the waste ink tank through the tube 77.

As shown in FIG. 3, the wiper 101 is located in the vicinity of the partition wall 18 in the second space 82. The wiper 101 can move in the vertical direction 7. After the ink is ejected empty, the wiper 101 is moved upward when the cap 73 moves from the cap position to the uncap position and the print head 24 moves from the second position to the first position. When the carriage 241 is moved from the second position to the first position while the wiper 101 is held at the upper position, the nozzle surface 243 of the print head 24 moves while being in contact with the upper end of the wiper 101. As a result, the ink adhering to the nozzle surface 243 is wiped off by the wiper 101. When the carriage 241 is positioned in the first position, the wiper 101 is moved to a lower position.

As shown in FIG. 2, the heater 26 is located above the transport path 22, downstream of the print head 24 and upstream of the second transport roller pair 55.

As shown in FIG. 4, the heater 26 is located downstream of the opening 72 in the transport direction. That is, the heater 26 and the opening 72 are positioned apart from each other in the transport direction.

The heater 26 is a so-called halogen heater. As shown in FIG. 2, the heater 26 has a halogen lamp 40, a reflector 41, and a housing 42, which are heating elements that emit infrared rays. The housing 42 has a substantially rectangular parallelepiped shape. An opening 43 along the left-right direction 9 is formed on the lower wall of the housing 42. Infrared light from the halogen lamp 40 and the reflector 41 is radiated to the outside through the opening 43. The halogen lamp 40 is located in the internal space of the housing 42. The halogen lamp 40 has an elongated cylindrical shape, and the left-right direction 9 is the longitudinal direction. In the internal space of the housing 42, the reflector 41 is located above the halogen lamp 40. The reflector 41 is a metal plate coated with a ceramic film or the like, and is curved in an arc shape with the vicinity of the opening 43 as the central axis. Instead of the reflector 41, a halogen lamp 40 coated with a ceramic film or the like may be used.

The heater 26 heats at least one of the sheet passing below the opening 43 and the ink adhering to the sheet. In this embodiment, the heater 26 heats both the sheet and the ink. When the ink is heated, the resin fine particles are glass-transitioned, and the sheet that has passed under the heater 26 is cooled, so that the glass-transitioned resin is cured. As a result, the ink is fixed on the sheet.

A temperature sensor 44 is provided in the vicinity of the heater 26. The temperature sensor 44 is a thermocouple, a thermistor, or the like. The temperature sensor 44 outputs a signal corresponding to the ambient temperature around the heater 26.

As shown in FIGS. 2 and 3, the transport belt 27 (an example of the second transport belt) is located below the heater 26. The transport belt 27 has a pair of pulleys 93, 94 (an example of a rotating body) and an endless belt 95 wound around the pulleys 93, 94. The pulleys 93 and 94 can rotate about an axis along the left-right direction 9, respectively. The pulleys 93 and 94 have the same shape including the outer diameter. The pulleys 93 and 94 are made of, for example, synthetic resin or metal. The pulleys 93 and 94 are separated from each other in the front-rear direction 8. An endless belt 95 is wound around the pulleys 93 and 94. The upper surface of the endless belt 95 faces the opening 43 of the heater 26. The dimension of the endless belt 95 along the left-right direction 9 is larger than the dimension of the roll paper 11 along the left-right direction 9.

The pulley 93 is provided with a rotary encoder 96 (an example of a speed sensor). The rotary encoder 96 has an encoder disk 97 and an optical sensor 98. The encoder disk 97 is provided coaxially with the pulley 93 and rotates together with the pulley 93. On the encoder disk 97, a plurality of two types of indexes having different transmittances are alternately arranged on the entire circumference in the circumferential direction. The optical sensor 98 can optically read two types of indexes of the encoder disk 97. When the optical sensor reads the two types of indexes of the rotating encoder disk 97, the two types of signals are output from the optical sensor 98 in a pulse shape. The output signal of the optical sensor 98 is received by a controller described later, and the rotation speed of the pulley 93 is determined. Although detailed description is omitted, the pulley 90 of the transport belt 25 is also provided with a rotary encoder 86 having an encoder disk 87 and an optical sensor 88.

The roll paper 11 conveyed through the transfer path 22 is supported on the upper surface of the endless belt 95 of the transfer belt 27 at a position facing the heater 26. The pulley 93 rotates when a drive is transmitted from a motor (not shown). The pulley 94 rotates together with the endless bell 95 that is rotated by the pulley 93. By rotating the endless belt 95, the roll paper 11 supported on the upper surface of the endless belt 95 is conveyed in the conveying direction. Although not shown in each figure, the roll paper 11 may be attracted to the upper surface of the endless belt 95 by applying an electrostatic force or a suction force to the endless belt 95.

Further, as shown in FIG. 2, a substrate 17A connected to the operation panel 17 is provided behind the operation panel 17.

As shown in FIG. 3, the control board 74 and the power supply circuit 75 are arranged in the second space 82. The arrangement positions of the control board 74 and the power supply circuit 75 shown in FIG. 3 are examples, and the control board 74 and the power supply circuit 75 can be arranged at arbitrary positions in the second space 82.

The control board 74 is a board made of glass epoxy or the like. Further, the control board 74 is mounted with a control circuit composed of a CPU, ROM, RAM, ASIC, and the like. The operation of the printing device 10 is controlled by the CPU executing the program stored in the ROM and the ASIC performing a specific function set. The control board 74 on which the control circuit is mounted is the controller 130 (see FIG. 4, an example of the control unit).

The power supply circuit 75 is a circuit configured by a large-capacity capacitor or the like. In the present embodiment, the power supply circuit 75 is mounted on a substrate made of paper phenol or the like. The power supply circuit 75 is a circuit that converts electric power for supplying power to each component included in the printing apparatus 10.

[Controller 130]
Hereinafter, the configuration of the controller 130 will be described with reference to FIG. The present invention is realized when the controller 130 performs a process according to a flowchart described later. The controller 130 controls the overall operation of the printing device 10. The controller 130 includes a CPU 131, a ROM 132, a RAM 133, an EEPROM 134, and an ASIC 135. The CPU 131, ROM 132, RAM 133, EEPROM 134, and ASIC 135 are connected by an internal bus 137.

The ROM 132 stores a program or the like for the CPU 131 to control various operations. The RAM 133 is used as a storage area for temporarily recording data, signals, etc. used by the CPU 131 when executing the program, or as a work area for data processing. The EEPROM 134 stores settings, flags, and the like that should be retained even after the power is turned off. For example, the EEPROM 134 stores a speed V1, a threshold value T, and a correction value Vt according to temperature.

The transport motors 100 and 101, the feed motor 102, and the carriage drive motor 103 are connected to the ASIC 135. The ASIC 135 incorporates a drive circuit that controls each motor. The CPU 131 outputs a drive signal for rotating each motor to a drive circuit corresponding to each motor. The drive circuit outputs a drive current corresponding to the drive signal acquired from the CPU 131 to the corresponding motor. This causes the corresponding motor to rotate. That is, the controller 130 controls the feeding motor 102 to rotate the feeding rollers 20 and 21. Further, the controller 130 controls the transport motor 100 to rotate the pulley 90. Further, the controller 130 controls the transport motor 101 to rotate the pulley 93. Further, the controller 130 controls the carriage driving motor 103 to move the carriage 40.

Further, rotary encoders 86 and 96 are connected to the ASIC 135. The controller 130 recognizes the rotation speed of the pulley 90 based on the output result of the rotary encoder 86. The controller 130 recognizes the rotation speed of the pulley 93 based on the output result of the rotary encoder 96.

Further, a temperature sensor 44 is connected to the ASIC 135. The controller 130 recognizes the ambient temperature of the heater 26 based on the output result of the temperature sensor 44.

A print head 24 is connected to the ASIC 135. The controller 130 controls the power supply to the print head 24, and selectively ejects ink droplets from each nozzle 30.

A power supply circuit 75 is connected to the ASIC 135. The ASIC 135 controls the power supply of the heater 26 to the halogen lamp 40 by controlling the power supply circuit 75. Although not shown in FIG. 4, electric power is supplied to each motor from the power supply circuit 75.

The controller 130 is not limited to the above, and only the CPU 131 may perform various processes, only the ASIC 135 may perform various processes, and the CPU 131 and the ASIC 135 cooperate with each other. It may perform various processes. Further, the controller 130 may be one in which one CPU 131 performs processing independently, or one in which a plurality of CPU 131s share the processing. Further, the controller 130 may be one in which one ASIC 135 performs processing independently, or a controller 130 in which a plurality of ASIC 135s share the processing.

[Operation of printing device 10]
The image recording operation by the printing apparatus 10 will be described below with reference to FIGS. 5 and 6.

Upon receiving the print data, the controller 130 controls a motor (not shown) to move the cap 73 at the cap position to the uncap position. Further, the carriage drive motor 103 is controlled to move the carriage 241 to move the print head 24 from the second position to the first position. Further, the controller 130 energizes the halogen lamp 40 of the heater 26 from the power supply circuit 75 (S10). Further, the controller 130 controls the feed motor 102 to rotate the feed rollers 20 and 21, and also controls the transport motors 100 and 101 to rotate the pulleys 90 and 93. As a result, the tip of the roll paper 11 is fed below the print head 24 at the first position (S11). In the rolled paper 11 that has been sent out, the surface of the roll that faces outward in the radial direction faces the print head 24 and the heater 26.

Then, the controller 130 controls the transport motors 100 and 102 and the feed motor 102 to rotate the feed rollers 20, 21 and pulleys 90 and 93, and rolls from the print head 24 based on the print data. Ink is ejected toward the paper 11 (S12).

The roll paper 11 transported on the transport belts 25 and 27 toward the discharge port 13 is formed between the first transport roller pair 54 and the second transport roller pair 55, the upper surface of the endless belt 92 of the transport belt 25, and It moves toward the discharge port 13 while being supported by the upper surface of the endless belt 95 of the transport belt 27. The ink droplets ejected from the print head 24 adhere to the roll paper 11 supported by the transport belt 25. When the roll paper 11 to which the ink droplets are attached reaches below the heater 26, the roll paper 11 is heated by the heater 26 while being supported by the transport belt 27. Ink droplets are fixed on the roll paper 11 by heating the heater 26.

In response to the determination that printing based on the print data has been completed (S13: Yes), the controller 130 rolls the roll paper 11 until the printed portion comes out of the discharge port 13 to the outside of the housing 14. After transporting 11, the transport motors 100 and 101 and the feed motor 102 are controlled to stop the rotation of the feed rollers 20 and 21 and the pulleys 90 and 93 (S14). Further, the controller 130 stops energization from the power supply circuit 75 to the halogen lamp 40 of the heater 26 (S15).

Hereinafter, the speed correction of the transport belt 27 will be described with reference to FIG.
When the controller 130 starts the transfer (S11), the controller 130 determines whether the temperature based on the signal received from the temperature sensor 44 is equal to or higher than the threshold value T according to the flow of FIG. 6 (S20). The controller 130 sets the rotation speed V1 as the rotation speed V of the pulley 93 according to the determination that the temperature is not equal to or higher than the threshold value T (S20: No) (S21). The rotation speed V1 is, for example, the same as the rotation speed of the pulley 90, and is predetermined and stored in the EEPROM 134.

The controller 130 determines the correction value Vt corresponding to the temperature according to the determination that the temperature is equal to or higher than the threshold value T (S20: Yes) and reads it from the EEPROM 134 (S22). As the correction value Vt, for example, a plurality of correction values Vt corresponding to each predetermined temperature range are stored in the EEPROM 134. Each correction value Vt is a value for lowering the rotation speed of the pulley 93. The plurality of correction values Vt are set so as to greatly reduce the rotational speed of the pulley 93 as the temperature range increases. The correction value Vt may be derived from a function with respect to temperature.

The controller 130 sets the rotation speed V of the pulley 93 to (V1-Vt) based on the correction value Vt read from the EEPROM 134 and the rotation speed V1 (S23).

Then, returning to the flow of FIG. 5, the controller 130 controls the pulley 93 based on the setting of either S21 or S23 to print S12. As a result, the endless belt 95 of the transport belt 27 rotates while moving at a transport speed along the transport direction.

[Action and effect of the embodiment]
In the above-described embodiment, the pulleys 93 and 94 may thermally expand as the temperature of the heater 26 rises. When the outer diameters of the pulleys 93 and 94 increase due to thermal expansion, the speed at which the endless belt 95 rotates, that is, the transport speed of the transport belt 27 increases. On the other hand, since the rotation speed of the pulley 93 is corrected by the correction value Vt corresponding to the ambient temperature of the heater 26, the time-dependent change of the transport speed of the transport belt 27 is suppressed.

[Modification example]
In the above-described embodiment, the controller 130 determines the correction value Vt based on the output of the temperature sensor 44, but instead of the temperature sensor 44, a speed sensor that detects the moving speed of the endless belt 95 of the transport belt 27 It may be provided. In the embodiment provided with the speed sensor, the controller 130 detects the moving speed Va of the endless belt 95 based on the output of the speed sensor. Then, the controller 130 may obtain the difference ΔV between the moving speed Va and the target speed Vb stored in advance in the RAM, and determine the correction value Vt according to the difference ΔV. The correction value Vt according to the difference ΔV is set so as to greatly reduce the rotation speed of the pulley 93 as the difference ΔV increases. The correction value Vt may be derived from a function for the difference ΔV.

Further, instead of the temperature sensor 44, the controller 130 may count the driving time of the heater 26. In the embodiment of counting the drive time of the heater 26, the controller 130 counts the elapsed time from driving the heater 26 (S10) to stopping the drive of the heater 26 (S15) based on a clock or the like. .. Then, the controller 130 may determine the correction value Vt according to the elapsed time. The correction value Vt according to the elapsed time is set so as to greatly reduce the rotation speed of the pulley 93 as the elapsed time increases. The correction value Vt may be derived from a function with respect to the elapsed time.

[Other variants]
The printing material is not limited to ink as long as it is fixed to the sheet by heating. Therefore, for example, the printing material may be toner or the like that is fixed to the sheet by heating. In that case, the heater 26 melts the toner in order to fix the toner on the sheet. Further, the transport belt 27 transports the sheet at a position facing the heater 26.

For example, as shown in FIG. 7, the heater 26 and the transport belt 27 may be provided in the transport path 112 between the photoconductor drum 110 and the fixing roller 111 that presses the toner onto the sheet. In the printing operation, toner is adhered to the sheet by the photoconductor drum 110. Then, while the sheet is conveyed by the conveying belt 27, the toner is heated by the heater 26. Then, the toner heated by the fixing roller 91 is pressure-bonded to the sheet.

Further, in the above-described embodiment, the temperature sensor 44 detects the ambient temperature of the heater 26, but instead of the temperature sensor 44, a temperature sensor that detects the temperature of the heater 26 itself may be provided.

Further, in the above-described embodiment, a so-called line head type head in which the print head 24 does not move when the printing device 10 prints on the roll paper 11 is adopted, but the present invention is not limited to this. For example, when the printing apparatus 10 prints on the roll paper 11, the print head 24 ejects ink while moving in the left-right direction 9 with respect to the stopped roll paper 11, and then the roll paper 11 causes a line break. A so-called serial head type head that is repeatedly transported to the paper may be adopted.

Further, the tank 70 is not limited to the one that stores the ink of one color of black, and may be the one that stores the inks of four colors of black, yellow, cyan, and magenta, respectively.

Further, the discharge port 13 does not necessarily have to be formed on the front wall 31 of the housing 14. For example, the discharge port 13 may be formed on the rear wall 33 of the housing 14, and the printed roll paper 11 passing through the discharge port 13 may be discharged diagonally upward or upward.

Further, the above-mentioned printing device 10 can print on the roll paper 11, but the printing device 10 is not limited to this, and for example, the printing device 10 may be a device that prints on the roll paper 11 and the cutting paper. However, the device may print only on the cutting paper.

Further, the above-mentioned printing device 10 is used in a state where the front wall 31 and the rear wall 32 of the housing 14 are along the vertical direction 7 and the horizontal direction 9, but the usage posture of the printing device 10 is not limited to this. ..

10 ... Printing device 24 ... Printing head (printing unit, head)
25 ... Conveyance belt (first transport belt)
26 ... Heater 27 ... Conveyance belt (second transport belt)
44 ... Temperature sensor 93, 94 ... Pulley (rotating body)
130 ... Controller (control unit)

Claims (6)

A printing unit that prints by attaching a printing material to a sheet that is transported in the transport direction,
A sheet located downstream of the printing unit in the transport direction and transported in the transport direction, and a heater that heats at least one of the printing materials adhering to the sheet.
A first transport belt that faces the printing unit and transports the sheet in the transport direction,
With a rotating body,
A second transport belt that faces the heater and transports the sheet in the transport direction by transmitting the rotation of the rotating body and moving at a transport speed.
It is equipped with a control unit.
The control unit
A correction value for correcting the rotation speed of the rotating body with respect to the time course change of the transfer speed of the second transport belt due to the heating of the heater is determined.
A printing device that drives the rotating body based on the determined correction value. It is further equipped with a temperature sensor that detects the temperature of the heater or the ambient temperature around the heater.
The printing apparatus according to claim 1, wherein the control unit determines the correction value according to the output of the temperature sensor. It is further equipped with a speed sensor for detecting the transfer speed of the second transfer belt.
The printing device according to claim 1, wherein the control unit determines the correction value according to the output of the speed sensor. The printing apparatus according to claim 1, wherein the control unit determines the correction value according to the driving time of the heater. The printing apparatus according to any one of claims 1 to 4, wherein the correction value is a value that reduces the rotation speed according to the passage of driving time of the heater. The printing apparatus according to any one of claims 1 to 5, wherein the printing unit is a head that discharges a liquid onto a sheet conveyed by the first conveying belt.

Images