JP2014184727A - Image recording apparatus and image recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the degradation of image quality of a recorded image.SOLUTION: An image recording apparatus comprises: a heating unit which is located further on a downstream side of a transport pathway than an image recording area, and further on an upstream side of the transport pathway than a transport roller which is rotated by a motor; and a control unit which lowers suction power of a suction unit to a medium from first suction power to second suction power lower than the first suction power during a recording operation, and causes first torque, which is generated at the motor in a period that is during the recording operation and the suction power of the suction unit is suction power lower than the first suction power, to be lower than second torque generated at the motor during the transport operation.

Description

  The present invention relates to an image recording apparatus and an image recording method.

As an image recording apparatus, there is a printer that prints an image by ejecting ink from a head onto a medium such as paper. In the printer, the medium is supported by the platen so that the medium is in a fixed posture with respect to the head, and the platen is provided with a suction hole so that the medium on the platen is held at a fixed position. There is a printer that sucks media from.
A printer having a drying unit (heating unit) that fixes an image on a medium by heating the medium on which the image is printed has also been proposed (for example, Patent Document 1).

JP 2010-125830 A

  When transporting the medium, it is preferable to reduce the suction force of the platen with respect to the medium. In particular, by lowering the suction force of the platen during printing, the medium can be transported immediately after printing is completed, and the overall work time can be shortened. However, in a printer that applies tension to the medium from the downstream side of the medium conveyance path during printing, if the suction force of the platen is reduced during printing, the platen The upper medium is pulled toward the drying unit. If it does so, the position of the medium on a platen will shift | deviate during printing, and the image quality of a printed image will deteriorate.

  The present invention has been made in view of such circumstances, and an object of the present invention is to suppress image quality deterioration of a recorded image.

The main invention for solving the above-described problems is that (A) a recording unit that records an image on a medium located in the image recording area, and (B) an opening portion of a suction hole that includes the medium located in the image recording area. A medium support unit supported by the provided support surface; (C) a suction unit for sucking the medium supported by the medium support unit through the suction hole; and (D) a transport path for transporting the medium by a transport roller. A transport unit that transports the transport roller along the transport path, the transport unit having a motor that rotates the transport roller located downstream of the transport path from the image recording area, and (E) an image recorded on the medium. A heating unit for fixing, the heating unit being located on the downstream side of the conveyance path with respect to the image recording region and on the upstream side of the conveyance path with respect to the conveyance roller rotated by the motor; Transport unit The medium transporting operation and the image recording operation by the recording unit are repeatedly executed, and the suction force of the suction unit with respect to the medium is changed from the first suction force to the first suction force during the recording operation. A first torque generated by the motor during a period in which the recording operation is being performed and the suction force of the suction unit is lower than the first suction force. An image recording apparatus comprising: (G) a control unit that lowers the second torque generated by the motor during the conveying operation.
Other features of the present invention will become apparent from the description of the present specification and the accompanying drawings.

1 is an overall configuration block diagram of a printer. 1 is a cross-sectional view illustrating an outline of a printer. It is a figure explaining the printing process of a comparative example. FIG. 9 is a diagram for explaining a roll paper shift in a printing process of a comparative example. It is a figure explaining the printing process of this embodiment. 6A and 6B are diagrams for describing a printing process according to a modification.

  At least the following matters will become apparent from the description of the present specification and the accompanying drawings.

That is, (A) a recording unit that records an image on a medium positioned in the image recording area, and (B) a medium that supports the medium positioned in the image recording area on a support surface provided with an opening of a suction hole. A support unit; (C) a suction unit that sucks the medium supported by the medium support unit through the suction hole; and (D) a transport unit that transports the medium along a transport path by a transport roller. A transport unit having a motor for rotating the transport roller located on the downstream side of the transport path from the image recording area, and (E) a heating unit for fixing the image recorded on the medium, A heating unit positioned downstream of the conveyance path from the image recording area and upstream of the conveyance roller rotated by the motor; and (F) a conveyance operation of the medium by the conveyance unit; The above The image recording operation by the unit is repeatedly executed, and during the recording operation, the suction force of the suction unit with respect to the medium is changed from the first suction force to a second suction force lower than the first suction force. The first torque generated by the motor during the recording operation and the suction force of the suction portion is lower than the first suction force is generated by the motor during the transport operation. An image recording apparatus comprising: a control unit that lowers the second torque to be generated; and (G).
According to such an image recording apparatus, it is possible to prevent the position of the medium supported by the medium support portion from being shifted during the recording operation, and it is possible to suppress deterioration in the image quality of the recorded image.

In this image recording apparatus, the control unit changes the torque generated by the motor to the first torque after the end of the transport operation and before the start of the recording operation.
According to such an image recording apparatus, it is possible to prevent the position of the medium supported by the medium support portion from being shifted during the recording operation, and it is possible to suppress deterioration in the image quality of the recorded image.

In this image recording apparatus, the control unit raises the suction force of the suction unit from the second suction force to the first suction force after the transport operation ends, and the suction force of the suction unit is increased. After reaching the first suction force, the torque generated by the motor is changed to the first torque.
According to such an image recording apparatus, the medium can be sucked and adsorbed to the medium support portion while the medium is stretched.

(A) a recording unit that records an image on a medium located in the image recording area; and (B) a medium that supports the medium located in the image recording area on a support surface provided with an opening of a suction hole. A support unit; (C) a suction unit that sucks the medium supported by the medium support unit through the suction hole; and (D) a transport unit that transports the medium along a transport path by a transport roller. A transport unit having a motor for rotating the transport roller located on the downstream side of the transport path from the image recording area, and (E) a heating unit for fixing the image recorded on the medium, A heating unit positioned downstream of the conveyance path from the image recording area and upstream of the conveyance roller rotated by the motor; and (F) a conveyance operation of the medium by the conveyance unit; The above The image recording operation by the unit is repeatedly executed, and during the recording operation, the suction force of the suction unit with respect to the medium is changed from the first suction force to a second suction force lower than the first suction force. The first torque generated by the motor during the recording operation and the suction force of the suction portion is lower than the first suction force is generated by the motor during the transport operation. An image recording method comprising: recording an image on the medium using an image recording apparatus provided with a control unit configured to lower the second torque to be performed and (G).
According to such an image recording method, it is possible to prevent the position of the medium supported by the medium support portion from being shifted during the recording operation, and it is possible to suppress deterioration in the image quality of the recorded image.

=== About the printer ===
Hereinafter, an embodiment will be described by taking an inkjet printer (hereinafter, a printer) as an example of the “image recording apparatus”.

  FIG. 1 is a block diagram of the overall configuration of the printer 1. FIG. 2 is a cross-sectional view illustrating an outline of the printer 1. The printer 1 of the present embodiment prints an image on a roll paper S (continuous paper) as a medium. The printer 1 is communicably connected to the computer 2, and the computer 2 creates print data for causing the printer 1 to print an image. The function of the computer 2 may be built in the printer 1.

  The controller 10 (corresponding to a control unit) is a control unit for controlling the printer 1. The interface unit 11 is for transmitting and receiving data between the computer 2 and the printer 1. The CPU 12 is an arithmetic processing unit for controlling the entire printer 1. The memory 13 is for securing an area for storing a program of the CPU 12, a work area, and the like. The CPU 12 controls each unit according to the unit control circuit 14. The detector group 70 monitors the situation in the printer 1, and the controller 10 controls each unit based on the detection result.

  The feeding unit 20 feeds the roll paper S to the transport unit 30. The feeding unit 20 includes a winding shaft 21 on which the roll paper S is wound and rotatably supported, and a relay roller 22 for winding the roll paper S fed from the winding shaft 21 and guiding it to the transport unit 30. Have. The feeding unit 20 is located outside the main body 1 ′ of the printer 1.

  The transport unit 30 (corresponding to the transport unit) transports the roll paper S sent from the feeding unit 20 from a upstream side to a downstream side along a preset transport path by a plurality of transport rollers. is there. The transport unit 30 includes a plurality of relay rollers 31 a to 31 f, a supply roller 32, a discharge roller 33, and a transport drive roller 34. As the roll paper S moves sequentially through these rollers, a transport path for transporting the roll paper S is formed.

The supply roller 32 is provided at a position immediately upstream of the printing area, and includes a pair of rollers 32a and 32b. The roll paper S is sandwiched between the two rollers 32a and 32b. One roller is a supply drive roller 32a that is rotated by the first motor M1, and the other roller is a supply follower roller 32b that rotates in conjunction with the supply drive roller 32a.
Further, the transport driving roller 34 is provided on the downstream side of the transport path with respect to the printing region and on the downstream side of the transport path with respect to the drying furnace 51 (described later). And the conveyance drive roller 34 is a drive roller rotated by the 2nd motor M2 (equivalent to the motor which a conveyance part has).

  The controller 10 prints an image on the roll paper S located in the print area, and then discharges the part of the roll paper S on which the image has been printed from the print area, and removes the part of the roll paper S on which the image has not yet been printed. Supply to the print area. That is, the controller 10 repeatedly executes the printing operation and the roll paper S transport operation alternately.

  Further, the controller 10 controls the position of the first motor M1 and controls the torque of the second motor M2. Then, the controller 10 controls the first motor M1 to rotate a predetermined amount of rotation during the transport operation, and controls the second motor M2 to generate a predetermined torque. Therefore, during the transport operation, the transport drive roller 34 is rotated by the torque generated by the second motor M2, and a tension for transporting the roll paper S to the downstream side of the transport path is applied to the roll paper S. At the same time, the supply roller 32 is also rotated by the first motor M1. As a result, the roll paper S is conveyed downstream in the conveyance path during the conveyance operation.

  The amount of rotation that the first motor M1 rotates during the transport operation corresponds to the length of the roll paper S that is transported in one transport operation. The torque generated by the second motor M2 during the transport operation is set so that tension is applied to the roll paper S so that the roll paper S does not flutter during the transport operation.

  Further, there are cases where the feeding of the roll paper S from the feeding unit 20 (winding shaft 21) cannot catch up during the transport operation. Accordingly, the roll paper S that is transported by one transport operation is wound around the relay rollers 31a and 31b positioned between the feeding unit 20 and the printing area and is loosened. The relay roller 31b located below the printer 1 can be operated in the vertical direction. By doing so, when the feeding of the roll paper S from the feeding unit 20 is delayed during the transport operation, the relay roller 31b is lifted and the loose roll paper S is supplied to the printing area. As a result, the roll paper S having a predetermined length can be supplied to the printing area in a predetermined conveyance time.

  The recording unit 40 (corresponding to a recording unit) prints (records) an image on the roll paper S located in the printing area. The recording unit 40 includes a carriage 41 and a head 42. The carriage 41 moves the head 42 in the X direction (the direction in which the roll paper S is conveyed) and the Y direction (the width direction of the roll paper S) while being guided by a guide shaft (not shown). The head 42 is for ejecting ink onto the roll paper S, and a plurality of nozzles serving as ink ejection portions are provided on the lower surface of the head 42. A two-dimensional image is printed on the roll paper S by ejecting ink while the head 42 moves together with the carriage 41 in the X and Y directions.

  The ink discharge method from the nozzle may be a piezo method in which voltage is applied to the drive element (piezo element) to expand and contract the pressure chamber to discharge ink, or bubbles are generated in the nozzle using a heating element. Alternatively, a thermal method in which ink is ejected by the bubbles may be used.

  In addition, the roll paper S located in the printing area is supported on the upper surface of the platen 43 from the back surface side opposite to the printing surface. A negative pressure chamber 45 is connected to the bottom surface of the platen 43, and a first fan mechanism 46 and a second fan mechanism 47 are attached to the bottom surface of the negative pressure chamber 45 in parallel. The second fan mechanism 47 includes two fans 47a and 47b, and the other fan 47b is attached to the lower side of the one fan 47a. The platen 43 is provided with a suction hole 44 penetrating in the vertical direction, and the negative pressure chamber 45 communicates with the outside (upper part of the platen 31) through the suction hole 44. That is, the platen 43 supports the roll paper S positioned in the printing area on the support surface (upper surface) provided with the opening of the suction hole 44.

  The first fan mechanism 46 and the second fan mechanism 47 discharge the air in the negative pressure chamber 45 to the outside, thereby bringing the negative pressure chamber 45 into a negative pressure state. At that time, outside air on the support surface of the platen 43 is sucked into the negative pressure chamber 45 through the suction holes 44, and the roll paper S on the platen 43 is sucked and adsorbed on the support surface of the platen 43. That is, the roll paper S on the platen 43 is sucked by the negative pressure chamber 45, the first fan mechanism 46, and the second fan mechanism 47 through the suction hole 44, and the roll paper S on the platen 43 is in a predetermined position. Retained. Hereinafter, the negative pressure chamber 45, the first fan mechanism 46, and the second fan mechanism 47 are collectively referred to as a “suction unit”.

  A plurality of heaters 48 (for example, nichrome wires) are disposed inside the platen 43. When the heater 48 is energized, the temperature of the platen 43 rises, and the temperature of the roll paper S on the platen 43 also rises. A heater 48 is provided over the entire area of the platen 43 so that heat is uniformly conducted to the roll paper S on the platen 43. As a result, it is possible to promote drying of the ink that has landed on the roll paper S on the platen 43, and it is possible to suppress bleeding of the ink in the printed image.

  The drying unit 50 (corresponding to a heating unit) has a drying furnace 51 for fixing an image printed on the roll paper S. The drying furnace 51 is located on the downstream side of the transport path with respect to the printing region and on the upstream side of the transport path with respect to the transport driving roller 34 rotated by the second motor M2. The drying furnace 51 has a plurality of fans 52 and a plurality of heaters 53. In the drying furnace 51, air heated by the heater 53 is blown by the fan 52 against the printing surface of the roll paper S supplied into the drying furnace 51. As a result, the ink constituting the image printed on the roll paper S can be dried, and the image printed on the roll paper S can be fixed on the roll paper S. Therefore, even when the rolled paper S that has been printed is wound up in a roll shape, the back surface of the rolled paper S can be prevented from being stained with ink, and a high-quality printed matter can be provided. The configuration of the drying furnace 51 is not limited to this, and high temperature air blown onto the roll paper S may be convected in the drying furnace 51, or the air in the drying furnace 51 is heated by the heater 53. It may be a configuration of only.

  The winding unit 60 is for winding the roll paper S (printed roll paper S) sent by the transport unit 30. The winding unit 60 includes a relay roller 61 that winds and transports the roll paper S sent from the transport driving roller 34, and a winding drive shaft 62 that winds the roll paper S. Note that the winding unit 60 is located outside the main body 1 ′ of the printer 1.

=== High suction mode / Low suction mode ===
As described above, in the printer 1 of the present embodiment, the roll supported by the platen 43 through the suction hole 44 by the suction unit (the negative pressure chamber 45, the first fan mechanism 46, and the second fan mechanism 47). The paper S is sucked and adsorbed on the support surface of the platen 43.

  During the printing operation, the platen 43 is held such that the roll paper S on the platen 43 is held at a predetermined position, and the roll paper S is held flat even if the roll paper S swells due to the moisture of the ink. I want to increase the suction and suction force of the upper roll paper S as much as possible. Since the roll paper S during the printing operation is held in a flat state, the heat of the heater 48 in the platen 43 is easily transferred to the roll paper S on the platen 43, and ink bleeding can be suppressed. Further, ink droplets can be landed on the correct position on the roll paper S, or contact between the roll paper S and the head 42 can be prevented.

  On the other hand, during the transport operation, it is desired to make the suction and suction force for the roll paper S on the platen 43 as weak as possible so that the roll paper S does not flutter so as not to cause a large resistance to transport.

  That is, the suction force of the suction portion with respect to the roll paper S on the platen 43 is desired to be weaker during the transport operation than during the print operation. Therefore, in the printer 1 of the present embodiment, the “high suction mode” in which the suction force of the suction portion with respect to the roll paper S is set to a high suction force (corresponding to the first suction force), and the suction force of the suction portion with respect to the roll paper S. Is provided with a “low suction mode” in which the suction force is lower than the suction force in the high suction mode (corresponding to the second suction force). Then, the controller 10 can switch between the high suction mode and the low suction mode.

  The controller 10 sets the high suction mode during the printing operation and sets the low suction mode during the transport operation. By doing so, the roll paper S on the platen 43 can be held flat at a predetermined position during the printing operation, and the roll paper S can be smoothly conveyed during the conveyance operation. Conversely, by setting the low suction mode during the transport operation, even if the transport force of the roll paper S by the transport unit 30 is weak (specifically, even if the torque value of the second motor M2 is low), The roll paper S can be conveyed. Therefore, cost reduction and power saving can be achieved.

  In order to change the suction force for the roll paper S on the platen 43, the negative pressure in the negative pressure chamber 45 may be changed. By increasing the negative pressure in the negative pressure chamber 45 (by reducing the pressure), the suction force to the roll paper S on the platen 43 can be increased, and by reducing the negative pressure in the negative pressure chamber 45. By increasing the pressure, the suction force for the roll paper S on the platen 43 can be reduced.

  The pressure in the negative pressure chamber 45 (negative pressure) may be set according to the conveyance force of the roll paper S by the conveyance unit 30, the type of the roll paper S, and the like. For example, in the high suction mode, the negative pressure chamber 45 The internal pressure is 805 Pa lower than the atmospheric pressure, and the pressure in the negative pressure chamber 45 is 140 Pa lower than the atmospheric pressure in the low suction mode. Further, the negative pressure chamber 45 is provided with a pressure sensor (not shown) for detecting the pressure in the negative pressure chamber 45 to check whether the pressure in the negative pressure chamber 45 is a desired pressure (negative pressure). You may do it.

  In the printer 1 of the present embodiment, in order to change the negative pressure in the negative pressure chamber 45 according to the mode, in the high suction mode, both the first fan mechanism 46 and the second fan mechanism 47 are turned on to reduce the low suction. In the mode, the first fan mechanism 46 is turned on and the second fan mechanism 47 is turned off.

  This is because when the two fans 47a and 47b are arranged in series as in the second fan mechanism 47 (when the fan shaft is arranged coaxially), one fan having the same characteristics (the first fan) This is because the static pressure can be improved as compared with the one fan mechanism 46). That is, the second fan mechanism 47 in which two fans are arranged in series exhales the air in the negative pressure chamber 45 than the first fan mechanism 46 constituted by one fan exhales the air in the negative pressure chamber 45. However, the negative pressure in the negative pressure chamber 45 can be increased.

  In the low suction mode, the second fan mechanism 47 is turned off, so that the air in the negative pressure chamber 45 is discharged to the outside by the first fan mechanism 46 and the second fan mechanism 47 in the negative pressure chamber 45. Is opened to the atmosphere. Therefore, the negative pressure in the negative pressure chamber 45 immediately decreases (pressure increases), and the switching from the high suction mode to the low suction mode can be performed quickly.

  In order to change the negative pressure in the negative pressure chamber 45, a first fan mechanism 46 constituted by one fan and a second fan mechanism 47 in which two fans 47a and 47b are arranged in series are arranged in parallel. The configuration is not limited to the above. For example, the negative pressure in the negative pressure chamber 45 can be changed by changing the rotational speed of the fan.

=== Print processing ===
<Print processing of comparative example>
FIG. 3 is a diagram for explaining the printing process of the comparative example, and FIG. 4 is a diagram for explaining the deviation of the roll paper S in the printing process of the comparative example. 3 is a graph showing the relationship between the suction force of the suction unit with respect to the roll paper S on the platen 43 and time, and the center diagram of FIG. 3 shows the relationship between the conveyance speed of the roll paper S and time. 3 is a graph showing the relationship between the torque generated by the second motor M2 that rotates the transport drive roller 34 and time. The printing operation is performed at “time 0 to t2”, and the conveyance operation is performed at “time t2 to t5”.

  As described above, it is preferable to increase the suction force of the suction portion with respect to the roll paper S on the platen 43 during the printing operation, and weaken the suction force of the suction portion with respect to the roll paper S on the platen 43 during the transport operation. It is preferable to do. However, if the high suction mode is maintained throughout the printing operation and the high suction mode is switched to the low suction mode after the completion of the printing operation, the transfer operation cannot be performed immediately after the printing operation is completed. . That is, a switching operation from the high suction mode to the low suction mode is required between the printing operation and the transport operation, and the entire work time is increased.

  Therefore, in the comparative example, the high suction mode is switched to the low suction mode during the printing operation. Here, the controller 10 switches from the high suction mode to the low suction mode at “time t1” during the printing operation. By doing so, since the switching operation from the high suction mode to the low suction mode is performed in parallel with the printing operation, the entire work time can be shortened. Note that after the conveyance operation is completed, a switching operation from the low suction mode to the high suction mode is performed, and then the printing operation is started again.

  Then, during the conveyance operation period (t2 to t5), the roll paper S is conveyed at a constant speed V during the acceleration (t2 to t3) when the roll paper S starts to move, as shown in the center diagram of FIG. Are divided into three periods, i.e., a constant speed (t3 to t4) and a deceleration (t4 to t5) before the roll paper S stops. Note that the conveyance speed of the roll paper S is 0 at times other than the conveyance operation.

  The controller 10 controls the torque generated by the second motor M2, and applies tension to the roll paper S to convey the roll paper S via the conveyance drive roller 34 rotated by the second motor M2. . Therefore, the controller 10 controls the torque of the second motor M2 so that the roll paper S is transported at the transport speed shown in the central view of FIG.

  Specifically, as shown in the lower diagram of FIG. 3, the highest torque T1 is generated by the second motor M2 during acceleration (t2 to t3), and the torque during acceleration at a constant speed (t3 to t4). The torque of the second motor M2 is generated so that the torque T2 lower than T1 is generated in the second motor M2, and the lowest torque T4 is generated in the second motor M2 during deceleration (t4 to t5). To control. Note that the controller 10 controls the torque generated by the second motor M2 by controlling the value of the current flowing through the second motor M2.

  In the comparative example, a relatively high tension is applied to the roll paper S even at times other than the conveyance operation (0 to t2, after t5). For this purpose, the controller 10 controls the second motor M2 to generate a torque T3 higher than the torque T4 during deceleration at times other than during the transport operation.

  On the other hand, the position of the first motor M1 that rotates the supply roller 32 on the upstream side of the printing area is controlled, and the portion of the roll paper S sandwiched between the supply rollers 32 remains in that position after the conveyance operation is finished. To be controlled.

  Therefore, the roll paper S between the supply roller 32 and the transport driving roller 34 is in a stretched state without slacking even at times other than during the transport operation. Therefore, contact between the fan 52 and the roll paper S in the drying furnace 51 can be prevented, or the next transport operation can be performed smoothly.

  By the way, in the printer 1, as shown in FIG. 4, the drying furnace is located at the downstream side of the transport path from the printing area and at the upstream side of the transport path from the transport driving roller 34 rotated by the second motor M2. 51 is provided. The inside of the drying furnace 51 is at a high temperature (for example, 75 degrees) in order to fix the image printed on the roll paper S. Therefore, the part of the roll paper S located in the drying furnace 51 contracts toward the center of the drying furnace 51 as the water and ink in the roll paper S evaporate.

  In this comparative example, a relatively high tension is applied to the roll paper S at times other than the conveyance operation. However, in the high suction mode, the suction force F1 of the suction portion, that is, the force that holds the roll paper S on the platen 43 in that position is strong. Therefore, in the high suction mode, the roll paper S on the platen 43 is placed at that position rather than the tension applied to the roll paper S by the second motor M2 (force that pulls the roll paper S to the downstream side of the transport path). The holding force is stronger. Therefore, when the roll paper S in the drying furnace 51 contracts in the high suction mode, the roll paper S on the transport driving roller 34 side (the roll paper S on the downstream side of the transport path from the drying furnace 51) is moved to the drying furnace 51 side. Be pulled.

  On the other hand, when the suction force of the suction portion is lower than the suction force F1 in the high suction mode (that is, in the switching operation or in the low suction mode), the second motor M2 applies it to the roll paper S. The force that holds the roll paper S on the platen 43 in that position is weaker than the tension that is applied. Therefore, when the roll paper S in the drying furnace 51 contracts during the switching operation or the low suction mode, as shown in FIG. 4, the roll paper S on the platen 43 side (the roll on the upstream side of the transport path from the drying furnace 51). The paper S) is pulled toward the drying furnace 51 side.

In this comparative example, the high suction mode is switched to the low suction mode during the printing operation in order to shorten the entire work time. Therefore, after switching from the high suction mode to the low suction mode (in FIG. 3, during the switching operation: time t1 to t2), when the roll paper S in the drying furnace 51 contracts, the printing operation is in progress. The roll paper S on the platen 43 is pulled toward the drying furnace 51 side (downstream of the transport path), and the image printing position is shifted. More specifically, the position of the image printed after switching from the high suction mode to the low suction mode is shifted to the upstream side of the transport path with respect to the position of the image printed in the high suction mode. As a result, the image quality of the printed image is degraded.
Therefore, an object of the present embodiment is to suppress deterioration in image quality of a print image.

<Print processing of this embodiment>
FIG. 5 is a diagram illustrating the printing process according to the present embodiment. The upper diagram of FIG. 5 is a graph showing the relationship between the suction force of the suction unit with respect to the roll paper S on the platen 43 and time, and the center diagram of FIG. 5 is a graph showing the relationship between the torque generated by the second motor M2 that rotates the transport drive roller 34 and time. It is assumed that the printing operation is performed at “time 0 to t2” and the conveyance operation is performed at “time t2 to t5”.

  Also in this embodiment, as in the comparative example, the high suction mode is switched to the low suction mode in the middle of the printing operation (time t1) in order to shorten the entire work time. That is, during the printing operation, the controller 10 changes the suction force of the suction portion with respect to the roll paper S from the high suction force F1 (corresponding to the first suction force) to the low suction force F2 (corresponding to the second suction force). Lower.

  However, during the printing operation of the comparative example (the lower diagram in FIG. 3), the torque T3 generated by the second motor M2 is set to be higher than the torque T4 during deceleration (during the transport operation). During the printing operation of the mode (lower diagram in FIG. 5), the torque T5 generated by the second motor M2 is set to be lower than the torque T4 during deceleration. Hereinafter, the torque T5 lower than the torque T4 at the time of deceleration is also referred to as “micro torque T5”.

  More specifically, in the printer 1 of the present embodiment, the drying is performed at a position on the downstream side of the conveyance path with respect to the printing region and on the upstream side of the conveyance path with respect to the conveyance driving roller 34 rotated by the second motor M2. A furnace 51 is provided, and the controller 10 switches from the high suction mode to the low suction mode in the middle of the printing operation, and the suction is being performed and the suction force of the suction portion is lower than the suction force F1 in the high suction mode. Torque T5 (corresponding to the first torque) generated by the second motor M2 during the period of force, and torques T1, T2, T4 (corresponding to the second torque) generated by the second motor M2 during the conveying operation ) Is lower.

  Therefore, in the present embodiment, the minute torque T5 generated by the second motor M2 during the period during which the printing operation is being performed and the suction force of the suction portion is lower than the suction force F1 in the high suction mode is used. The force can be lowered as the force that holds the roll paper S on the platen 43 in that position becomes stronger than the tension applied to the roll paper S by the torque T5.

  Therefore, in this embodiment, after the high suction mode is switched to the low suction mode during the printing operation, after the suction force of the suction unit becomes weaker than the suction force F1 in the high suction mode, the roll paper S in the drying furnace 51 is used. Even if the shrinkage occurs, as in the high suction mode, the roll paper S on the transport drive roller 34 side (the roll paper S on the downstream side of the transport path from the drying furnace 51) is pulled to the drying furnace 51 side. That is, in this embodiment, even if the high suction mode is switched to the low suction mode during the printing operation, the position of the roll paper S on the platen 43 can be prevented from shifting during the printing operation, and the image printing position can be prevented. Misalignment can be prevented. In other words, in the present embodiment, it is possible to suppress the deterioration of the image quality of the printed image while reducing the overall work time.

  The period during which the printing operation is being performed and the suction force of the suction part is lower than the suction force F1 in the high suction mode corresponds to the switching operation period (time t1 to t2) in FIG.

  Further, in the present embodiment, the second operation is also very small during the period (t1 to t2) during which the printing operation is being performed and the suction force of the suction portion is lower than the suction force F1 in the high suction mode. Torque T5 is generated in the motor M2. If no torque is generated in the second motor M2 during this period (t1 to t2) (that is, if the torque of the second motor M2 is set to 0), the conveyance drive roller 34 and the printing area The roll paper S in between is loosened. If it does so, the fan 52 and the roll paper S in the drying furnace 51 may contact, or the next conveyance operation cannot be performed smoothly.

  On the other hand, as in the comparative example (FIG. 3), during this period (t1 to t2), the second motor M2 generates more torque than necessary (ie, torque T3 larger than torque T4 during deceleration). Then, due to the expansion and contraction of the roll paper S in the drying furnace 51, the position of the roll paper S on the platen 43 side is shifted. As a result, the printing position of the image is shifted, and the image quality of the printed image is deteriorated.

  Therefore, as in this embodiment, during the printing operation and during the period (t1 to t2) in which the suction force of the suction portion is lower than the suction force F1 in the high suction mode, the second motor M2 is used. It is preferable to generate a minute torque T5. By doing so, it is possible to prevent an image printing position shift while preventing the looseness of the roll paper S between the transport driving roller 34 and the printing region.

  That is, in the present embodiment, the roll paper S is loaded in the drying furnace 51 during a period (t1 to t2) in which the suction force of the suction portion is lower than the suction force F1 in the high suction mode during the printing operation. When the second motor M2 expands and contracts, the second motor M2 is caused to generate a minute torque T5 that rotates the second motor M2 in the direction opposite to that during the transport operation. In other words, with the second motor M2, the tension applied to the roll paper S by the minute torque T5 is overwhelmingly weaker than the force that holds the roll paper S on the platen 43 in that position. The generated torque T5 is made minute.

  For example, in this period (t1 to t2), in the comparative example, the second motor M2 generates a torque of 33N, whereas in the present embodiment, the second motor M2 has a torque of 1N or less (however, 0N is included) Not to be generated). The controller 10 controls the torque generated by the second motor M2 by controlling the value of the current that flows through the second motor M2. Therefore, in this period (t1 to t2), for example, in the comparative example, a current of 1 A is supplied to the second motor M2, whereas in this embodiment, a current of 0.27 A is supplied to the second motor M2. It is good to.

  Even during the printing operation, if the high suction mode is in effect (time 0 to t1), even if the torque generated by the second motor M2 is set to a torque larger than the minute torque T5, the drying furnace 51 There is no possibility that the roll paper S on the platen 43 side is displaced due to the expansion and contraction of the roll paper S. However, the position of the first motor M1 is controlled. Therefore, after the end of the transport operation, the first motor M1 tries to stay at that position (that is, the force that the roll paper S sandwiched between the supply rollers 32 tries to stay at that position), and the second The tension applied to the roll paper S by the motor M2 is stable in a balanced state.

  When the torque value of the second motor M2 is changed in this balanced state, the force at which the roll paper S sandwiched between the supply rollers 32 tries to stay at that position and the second moment are changed when the torque value is changed. The balance with the tension applied to the roll paper S by the motor M2 may be lost. At the moment when the balance is lost, the roll paper S on the platen 43 may be shifted to the upstream side (first motor M1 side) of the transport path. For this reason, if the torque of the second motor M2 is reduced from the torque T4 during deceleration to the minute torque T5 during the printing operation, the image printing position may be shifted.

  Therefore, in the present embodiment, the torque generated by the second motor M2 is changed to the minute torque T5 after the end of the transport operation and before the start of the printing operation (between t5 and t6 in FIG. 5). That is, the controller 10 lowers the torque generated by the second motor M2 from the torque T4 during deceleration (torque during the conveyance operation) to the minute torque T5 after the completion of the conveyance operation and before the start of the printing operation. Here, as shown in the lower diagram of FIG. 5, immediately before the start of the printing operation (time t6), the torque generated by the second motor M2 is reduced from the torque T4 during deceleration to the minute torque T5.

  By doing so, since the torque of the second motor M2 does not fluctuate during the printing operation, the roll paper S sandwiched between the supply rollers 32 and the force that causes the roll motor S2 to stay in that position and the second motor M2 to roll the paper S. It is possible to prevent the balance with the tension applied to the material from being lost. Therefore, it is possible to prevent the position of the roll paper S on the platen 43 from being shifted during the printing operation and the image printing position from being shifted.

  Further, in the present embodiment, after the transfer operation is completed, the switching operation from the low suction mode to the high suction mode is performed (the suction force of the suction unit is increased from the second suction force to the first suction force), and the suction unit After the suction force reaches the suction force F1 in the high suction mode, the torque generated by the second motor M2 is changed to the minute torque T5. That is, after the suction force of the suction part reaches the suction force F1 in the high suction mode, the controller 10 reduces the torque generated by the second motor M2 from the torque T4 at the time of deceleration (torque during the transport operation). Reduce to torque T5. Here, as shown in the lower diagram of FIG. 5, immediately after the end of the switching operation (time t6), the torque generated by the second motor M2 is reduced from the torque T4 during deceleration to the minute torque T5.

  By doing so, it is possible to switch from the low suction mode to the high suction mode in a state where torque larger than the minute torque T5 (here, torque T4 during deceleration) is generated in the second motor M2. That is, in a state where a relatively large tension is applied to the roll paper S, the low suction mode is switched to the high suction mode. Therefore, the roll paper S can be sucked and adsorbed on the support surface of the platen 43 in a state where the roll paper S is stretched smoothly. As a result, a predetermined portion of the roll paper S can be sucked and adsorbed on the support surface of the platen 43 in a flat state.

  In this embodiment, in order to reduce the overall work time, the high suction mode is switched to the low suction mode during the printing operation, but the switching operation from the high suction mode to the low suction mode is performed in the latter half of the printing operation. Preferably it is done. Furthermore, it is preferable to start the switching operation from the high suction mode to the low suction mode at the time (time t1) when the time required for the switching operation is calculated backward from the end time of the printing operation (time t2). By doing so, the time of the high suction mode during the printing operation can be made as long as possible. As a result, the roll paper S on the platen 43 can be held in a flat state at a predetermined position for a longer time during the printing operation.

<Modification>
6A and 6B are diagrams for describing a printing process according to a modification. In the above-described embodiment (FIG. 5), the torque generated by the second motor M2 is changed from the torque T4 at the time of deceleration to the minute torque at “time t6” immediately after the end of the switching operation and immediately before the start of the printing operation. Although it is lowered to T5, it is not limited to this.

  For example, as shown in FIG. 6A, the torque generated by the second motor M2 may be reduced from the torque T4 during deceleration to the minute torque T5 at “time t5” immediately after the end of the transport operation. In this case, during the printing operation, the roll in the drying furnace 51 is in a period during which the suction force of the suction portion is lower than the suction force F1 in the high suction mode (t1 to t2 during the switching operation in FIG. 6A). Even if the paper S expands and contracts, it is possible to prevent the position of the roll paper S on the platen 43 from being displaced, and to suppress deterioration in image quality of the printed image.

  Further, for example, as shown in FIG. 6B, the torque generated by the second motor M2 during the period from the end of the transport operation to the start of the switching operation during the printing operation is higher than the minute torque T5 ( For example, the torque T4 during deceleration or the torque T3 higher than the torque T4 during deceleration may be set. Then, the torque generated by the second motor M2 may be changed to the minute torque T5 before the start of the switching operation during the printing operation.

  In this case, in the period when the printing operation is being performed and the suction force of the suction portion is lower than the suction force F1 in the high suction mode (t1 to t2 during the switching operation in FIG. 6B), the rolls are dried in the drying furnace 51. Even if the paper S expands and contracts, it is possible to prevent the position of the roll paper S on the platen 43 from being displaced, and to suppress deterioration in image quality of the printed image.

  However, if the torque generated by the second motor M2 is changed during the printing operation, the roll paper S sandwiched between the supply rollers 32 and the force of the second motor M2 causing the roll paper S to stay in that position. The balance with the tension applied to S may be lost, and the print position of the image may be shifted. Therefore, it is preferable to change the torque generated by the second motor M2 to the minute torque T5 before starting the printing operation as in the above-described embodiment.

=== Other Embodiments ===
Although the present embodiment is mainly described with respect to an image recording apparatus, disclosure of an image recording method and the like is also included. Further, the present embodiment is intended to facilitate understanding of the present invention and is not intended to limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and it is needless to say that the present invention includes equivalents thereof. In particular, the embodiments described below are also included in the present invention.

<About the printer>
In the above-described embodiment, the printer 1 that prints an image while moving the head 42 in the X direction and the Y direction with respect to the roll paper S positioned in the printing area is described as an example, but the present invention is not limited thereto. For example, a printer that prints an image when the roll paper S passes under a fixed head may be used.
The medium on which the image is recorded is not limited to roll paper but may be cut sheet paper or an image recording apparatus that records an image on the medium by ejecting fluid other than ink from the nozzles.
Further, the image recording apparatus is not limited to a printer. For example, a color filter manufacturing apparatus, a staining apparatus, a fine processing apparatus, a semiconductor manufacturing apparatus, a surface processing apparatus, a three-dimensional modeling machine, a gas vaporization apparatus, an organic EL manufacturing apparatus (particularly a polymer The same technology as that of the above-described embodiment may be applied to various devices to which inkjet technology is applied such as an EL manufacturing device, a display manufacturing device, a film forming device, and a DNA chip manufacturing device.

  DESCRIPTION OF SYMBOLS 1 Printer, 1 'main body part, 2 Computer, 10 Controller, 11 Interface part, 12 CPU, 13 Memory, 14 Unit control circuit, 20 Feeding unit, 21 Winding axis, 22 Relay roller, 30 Conveyance unit, 31a-31f Relay Roller, 32 supply roller, 33 discharge roller, 34 transport drive roller, M1 first motor, M2 second motor, 40 recording unit, 41 carriage, 42 head, 43 platen, 44 suction hole, 45 negative pressure chamber, 46 First fan mechanism, 47 Second fan mechanism, 48 heater 50 drying unit, 51 drying furnace, 52 fan, 53 heater, 60 winding unit, 61 relay roller, 62 winding drive shaft.

Claims (4)

(A) a recording unit that records an image on a medium located in the image recording area;
(B) a medium support unit that supports the medium positioned in the image recording area on a support surface provided with an opening of a suction hole;
(C) a suction part that sucks the medium supported by the medium support part through the suction hole;
(D) a transport unit that transports the medium along a transport path by a transport roller, the transport unit having a motor that rotates the transport roller positioned downstream of the transport path from the image recording area;
(E) A heating unit for fixing an image recorded on the medium, which is downstream of the conveyance path from the image recording area, and upstream of the conveyance roller rotated by the motor. A heating unit located in
(F) repeatedly performing the medium transport operation by the transport unit and the image recording operation by the recording unit;
During the recording operation, the suction force of the suction portion with respect to the medium is lowered from the first suction force to a second suction force lower than the first suction force,
A first torque generated by the motor during the recording operation and generated by the motor during the transporting operation is a period during which the suction force of the suction unit is lower than the first suction force. A control unit for lowering the torque than 2;
An image recording apparatus comprising (G). The image recording apparatus according to claim 1,
The controller changes the torque generated by the motor to the first torque after the end of the transport operation and before the start of the recording operation.
Image recording device. The image recording apparatus according to claim 1 or 2, wherein
The controller is
After completion of the transport operation, the suction force of the suction part is increased from the second suction force to the first suction force,
After the suction force of the suction part reaches the first suction force, the torque generated by the motor is changed to the first torque;
Image recording device. (A) a recording unit that records an image on a medium located in the image recording area;
(B) a medium support unit that supports the medium positioned in the image recording area on a support surface provided with an opening of a suction hole;
(C) a suction part that sucks the medium supported by the medium support part through the suction hole;
(D) a transport unit that transports the medium along a transport path by a transport roller, the transport unit having a motor that rotates the transport roller positioned downstream of the transport path from the image recording area;
(E) A heating unit for fixing an image recorded on the medium, which is downstream of the conveyance path from the image recording area, and upstream of the conveyance roller rotated by the motor. A heating unit located in
(F) repeatedly performing the medium transport operation by the transport unit and the image recording operation by the recording unit;
During the recording operation, the suction force of the suction portion with respect to the medium is lowered from the first suction force to a second suction force lower than the first suction force,
A first torque generated by the motor during the recording operation and generated by the motor during the transporting operation is a period during which the suction force of the suction unit is lower than the first suction force. A control unit for lowering the torque than 2;
An image recording method comprising: recording an image on the medium using an image recording apparatus comprising (G).

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