Conveying device and recording device

Abstract

To provide a conveying device capable of suppressing sheet conveyance failure.SOLUTION: The conveying device includes: a conveying section that conveys a sheet while applying tension to the sheet along a sheet conveying direction; and a tension detection section that detects tension of the sheet being conveyed to the conveying section. The tension detection section is configured to be switchable between a first mode capable of detecting tension of a value between a first lower limit value TL1 and a first upper limit value TU1, and a second mode capable of detecting tension between a second lower limit value TL2 greater than the first lower limit value TL1 and a second upper limit value TU2 greater than the first upper limit value TU1. The conveying device includes a control section that switches between the first mode and the second mode based on the tension detected by the tension detection section.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a transport device and a recording device including the transport device. [Background technology]

[0002] Conventionally, as a conveying device for conveying a sheet as a conveying medium, a configuration is known in which the sheet is conveyed while tension is applied to the sheet along the conveying direction. Patent Document 1 discloses a configuration in which the sheet conveying speed is controlled based on the tension detected by a tension detection unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-145499 A Summary of the Invention [Problem to be solved by the invention]

[0004] Various types of conveying media, such as film, plain paper, and cardboard, can be used as the sheet to be conveyed by the conveying device. However, there is a large gap in the tension detection range between film, which should be conveyed with low tension to prevent stretching, and cardboard, which should be conveyed with high tension to prevent slack. Therefore, if a configuration is adopted in which the tensions of multiple types of sheets are detected by a common detection circuit, the tension detection range is wide, resulting in low resolution and making it difficult to control the tension with high precision. If the tension control is not precise enough, the sheet may stretch in the conveying direction, or the sheet may slacken and cause a jam, resulting in poor conveying.

[0005] In order to solve the above-mentioned problems, an object of the present invention is to provide a conveying device capable of suppressing sheet conveyance failure. [Means for solving the problem]

[0006] In order to achieve the above object, the conveying device of the present invention comprises: a conveying section that conveys the sheet while applying tension to the sheet along a conveying direction of the sheet; a tension detection unit that detects tension of the sheet being conveyed to the conveying unit; Equipped with the tension detection unit is configured to be switchable between a first mode capable of detecting tension between a first lower limit value and a first upper limit value, and a second mode capable of detecting tension between a second lower limit value larger than the first lower limit value and a second upper limit value larger than the first upper limit value, The tension detecting unit detects the tension, and the control unit switches between the first mode and the second mode based on the tension detected by the tension detecting unit. Effect of the Invention

[0007] According to the present invention, it is possible to provide a conveying device capable of suppressing sheet conveyance failure. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a schematic cross-sectional view showing the configuration of the recording apparatus of the first embodiment during recording. [Diagram 2] FIG. 2 is a schematic cross-sectional view showing the configuration of the recording apparatus of the first embodiment during cleaning. [Diagram 3] FIG. 1 is a block diagram of a recording apparatus according to a first embodiment. [Figure 4] FIG. 2 is a block diagram of a tension control configuration according to the first embodiment. [Diagram 5] FIG. 2 is a block diagram of a switching unit according to the first embodiment. [Figure 6] FIG. 4 is a tension detection characteristic diagram of the first embodiment. [Figure 7] 4 is a flowchart of tension control in the first embodiment. [Figure 8] 4 is a flowchart of tension control in the first embodiment. [Figure 9] FIG. 11 is a tension detection characteristic diagram of the second embodiment. [Figure 10]10 is a flowchart of tension control in the second embodiment. [Figure 11] 10 is a flowchart of tension control in the second embodiment. [Figure 12] FIG. 13 is a tension detection characteristic diagram of the third embodiment. [Figure 13] 13 is a flowchart of tension control in the third embodiment. [Figure 14] 13 is a flowchart of tension control in the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiment of the present invention will be described in detail with reference to the drawings. Note that the dimensions, materials, shapes, and relative positions of the components described in the embodiment may be changed as appropriate depending on the configuration of the device to which the invention is applied and various conditions. In other words, the scope of the present invention is not limited to the following embodiment.

[0010] The conveying device of the present invention can be applied to, for example, a recording device that records an image on a sheet as a recording medium while conveying the sheet. Hereinafter, a high-speed line printer that uses a continuous sheet wound in a roll will be described as an example of a recording device to which the present invention is applied. Such a recording device is suitable for the printing field, for example, for mass printing in print laboratories. However, the application of the present invention is not limited to high-speed line printers, and can be applied to various recording devices and other devices that convey sheets.

[0011] <Example 1> (Recording device) First, a schematic configuration of a recording device 101 according to a first embodiment will be described with reference to Fig. 1. Fig. 1 is a schematic cross-sectional view showing the internal configuration of the recording device 101. In the following description, the up-down direction of the paper surface of Fig. 1 is the up-down direction of the recording device 101. In the first embodiment, a sheet as a recording medium (conveying medium) is conveyed from right to left on the paper surface so that the direction from the front to the back of the paper surface of Fig. 1 corresponds to the sheet width direction.

[0012] Inside the main body of the recording device 101 of the first embodiment, a sheet supply unit 102, a sheet identification sensor 103, a first conveying roller pair 104, a meandering correction unit 105, a tension detection unit 106, and a recording unit 107 are provided in this order along a sheet conveying path S. Furthermore, downstream of the recording unit 107 in the sheet conveying direction, a post-processing unit 109, a second conveying roller pair 110, and a sheet recovery unit 111 are provided in this order along the sheet conveying path S. In addition to the above-mentioned units, the recording device 101 also includes a head cleaning unit 108, a controller unit 301, and a print engine unit 302. In FIG. 1, the sheet conveying path S is indicated by a solid line. In a recording operation by the recording device 101, a sheet is conveyed along the conveying path S while undergoing a predetermined process in each unit.

[0013] The sheet supply unit 102 is a unit for holding and supplying a continuous sheet wound in a roll. The sheet supply unit 102 is configured to store a roll 113 and pull out and supply a sheet. The number of rolls that can be stored is not limited to one, and the unit may store two or three or more rolls and selectively pull out and supply a sheet. In addition, the sheet is not limited to being wound in a roll as long as it is a continuous sheet. For example, a continuous sheet with perforations for each unit length may be folded back at each perforation and stacked, and stored in the sheet supply unit 102.

[0014] The sheet identification sensor 103 is used to identify a sheet (conveyed medium). In the first embodiment, the identification sensor is used as a means for identifying the sheet, but the sheet may be identified by a human being who performs the identification and inputs the identification result to the operation unit 119.

[0015] The first conveying roller pair 104 is a conveying unit that sends the sheet to a meandering correction unit 105, a tension detection unit 106, a recording unit 107, and a post-processing unit 109, which are arranged in the following order along a sheet conveying path S. The first conveying roller pair 104 is also a tension applying unit that applies sheet tension between the first conveying roller pair 104 and a second conveying roller pair 110. The first conveying roller pair 3 rotates by driving a motor (not shown) to convey the sheet with tension.

[0016] The meandering correction unit 105 is a unit for correcting meandering in the sheet width direction when the sheet is conveyed under tension. The meandering correction unit 105 is configured to include a meandering correction roller 105a and a meandering detection sensor (not shown) for detecting meandering of the sheet. The meandering correction roller 105a can change the inclination with respect to the sheet by a motor (not shown), and corrects meandering of the sheet based on the measurement by the meandering detection sensor. At this time, the sheet is wrapped around the meandering correction roller 105a, thereby improving the meandering correction function.

[0017] The tension detection unit 106 is a unit for detecting tension when tension transport is performed between the first transport roller pair 104 and the second transport roller pair 110. As the tension detection unit 106, for example, a known tension detection means that converts tension into a load and extracts the load as an electrical signal can be appropriately used. The type of the tension detection unit can also be a known detection type, such as a differential transformer type or a strain gauge type, depending on the configuration of the transport unit.

[0018] The recording unit 107 is a sheet processing unit that performs recording processing on the conveyed sheet from above using a recording head 114 to form an image on the sheet. A conveying path S in the recording unit 107 is formed by guide rollers 115 arranged in an upwardly convex arc shape, and a certain tension is applied to the sheet to ensure a clearance between the sheet and the recording head 114.

[0019] In the first embodiment, a plurality of recording heads 114 are arranged in an arc shape following the transport path S (along the transport direction). In the first embodiment, four line-type recording heads corresponding to four colors, Bk (black), Y (yellow), M (magenta), and C (cyan), are provided as the recording heads 114. The number of colors and the number of recording heads 114 are not limited to four. The plurality of recording heads 114 are integrally held by a head holder 116. The head holder 116 is configured to be movable in the vertical direction so that the clearance between the sheet and the recording heads 114 can be changed. As the inkjet method, a method using a heating element, a method using a piezoelectric element, a method using an electrostatic element, a method using a MEMS element, or the like can be adopted. Ink of each color is supplied to the recording head 114 from an ink tank (not shown) through an ink tube.

[0020] The head cleaning unit 108 is composed of a cleaning unit (not shown) that cleans the ink ejection surface of the recording head 114, and a cap unit 117 that moisturizes the ink ejection surface of the recording head 114. The cleaning unit may be selected from a wide variety of options depending on the characteristics of the ink used, the recording time, and the interval, and may be any type of unit, including wiping with an elastic blade such as urethane, suction with a strip-shaped cloth or nonwoven fabric, or a rubber suction nozzle, and is not limited thereto.

[0021] The cap unit 117 is a rubber member molded in a barrel shape that covers the ejection nozzle area of ​​the ink ejection surface. By contacting the outside of the area, contact between the outside air and the discharge nozzle is reduced, and drying is suppressed. The form is not limited, and a sealed space may be created by arranging rubber ribs or the like on a plate-shaped member and contacting the ribs. Also, in order to make the pressure on the discharge nozzle equal to atmospheric pressure, an air communication passage may be provided within a range that does not affect the suppression of drying. Furthermore, a configuration may be adopted in which negative pressure is applied to the sealed space to suck ink out of the nozzle. In order to increase the moisture retention ability, a configuration may be adopted in which liquid is supplied into the cap to increase humidity.

[0022] A plurality of cleaning units corresponding to a plurality of recording heads 114 and a cap unit 117 are arranged in an arc shape, and are integrally held by a cleaning holder 118. The head cleaning section 108 is configured to be slidable between a facing position facing the recording heads 114 and a retracted position retracted from the position facing the recording heads 114.

[0023] During a recording operation on a sheet, the head cleaning unit 108 is located at the retracted position shown in FIG. 1. On the other hand, during a cleaning operation of the recording head 114, the head cleaning unit 108 is located at the opposing position. FIG. 2 is a schematic diagram showing the internal configuration of the recording device 101 in a state in which the head cleaning unit 108 is located at the opposing position. When the head cleaning unit 108 is located at the opposing position, each cap unit 117 is located directly below the corresponding recording head 114. When the head cleaning unit 108 slides from the retracted position (position in FIG. 1) to the opposing position (position in FIG. 2), the head holder 116 is raised in advance, the head cleaning unit 108 is slid, and then the head holder 116 is lowered. Note that the head cleaning unit 108 is not limited to being composed of a cleaning unit and a cap unit 117, and may be composed of only one of the cleaning unit and the cap unit 117. Furthermore, the sliding direction of the head cleaning unit 108 may be along the sheet conveying direction or along the sheet width direction.

[0024] The post-processing unit 109 is a unit that reduces the liquid content contained in the ink applied onto the sheet by the recording unit 107 and improves the fixation of the ink to the sheet. The post-processing unit 109 is composed of a drying unit 121, a fixing unit 122, and a cooling unit 123.

[0025] The drying unit 121 heats the recorded sheet to dry the applied ink. Inside the drying unit 121, hot air is applied to at least the upper surface side of the sheet passing through to dry the ink applied surface. Note that the drying method may be a combination of a method of applying hot air, a method of irradiating the sheet surface with electromagnetic waves (ultraviolet rays, infrared rays, etc.), and a conductive heat transfer method by contact with a heating element.

[0026] The fixing unit 122 applies a predetermined amount of heat to the sheet dried in the drying unit 121, softening and melting the ink, thereby improving the fixation of the ink to the sheet. Inside the fixing unit 122, hot air equal to or greater than the amount of heat of the drying unit 121 is applied to the sheet passing through at least from the upper surface side, thereby fixing the image (ink) to the ink-applied surface. Note that the fixing method is not limited to the method of applying hot air, and may be a method of irradiating the sheet surface with electromagnetic waves (ultraviolet rays, infrared rays, etc.), a method of clamping the sheet with a heating element and applying heat and pressure, or a combination of these.

[0027] The cooling section 123 cools the sheet on which the image has been fixed by the fixing section 122, solidifies the softened ink, and suppresses the amount of change in the sheet temperature in downstream processes of the recording device. Inside the cooling section 123, air with a lower temperature than the sheet is blown onto at least the upper surface side of the passing sheet to cool the ink application surface. The cooling method is not limited to the method of blowing air, and may be a conductive heat transfer method using contact with a heat dissipation member, or a combination of these.

[0028] The second conveying roller pair 110 is a unit that conveys the sheet while applying tension to the sheet together with the first conveying roller pair 104, and adjusts the tension of the sheet. The roller pair 110 is rotated by being driven by a motor (not shown). In the first embodiment, the print engine unit 302 adjusts the tension by controlling the speed of the second conveying roller pair 110 in accordance with the tension detected by the tension detection unit 106. Thus, in the first embodiment, the conveying unit that conveys the sheet while applying tension to the sheet along the sheet conveying direction includes the first conveying roller pair 104 and the second conveying roller pair 110. The first conveying roller pair 104 and the second conveying roller pair 110 also function as tension adjustment means that can adjust the tension of the sheet.

[0029] The sheet tension adjustment means is not limited to the above-mentioned configuration. For example, a clutch may be provided as an additional configuration for adjusting the sheet tension. A mechanism may be added that can adjust the sheet tension by controlling the torque of the clutch based on the detection result of the tension detection unit 106. In this case, there are two methods: a speed control method for controlling the roller speed of the second conveying roller pair, and a torque control method for controlling the torque value transmitted from the clutch. Depending on the purpose, the tension control methods can be switched or both can be used simultaneously.

[0030] The sheet recovery unit 111 is a unit for winding the recorded sheet onto a core. The number of recoverable rolls is not limited to one, and may have two or three or more cores and may be configured to selectively switch between them to recover the sheet. Depending on the content of the post-recording processing, the continuous sheet may be cut using a cutter and the cut sheets may be stacked, instead of being wound onto a core.

[0031] The controller unit 301 is a unit that controls each part of the entire recording device 101. The controller unit 301 has a CPU, a storage device, a controller equipped with various control units, an external interface (I / F), and an operation unit 308 through which a user performs input and output. The operation of the recording device 101 is controlled based on commands from the controller or a host device 120 such as a host computer connected to the controller via an external interface.

[0032] The print engine unit 302 is a unit that mainly controls the conveying unit and the recording unit of the recording device 101. The print engine unit 302 drives the first conveying roller pair 104 and the second conveying roller pair 110 based on the detection result of the tension detection unit 106, to control the sheet conveying speed and tension.

[0033] (Overall control configuration of the recording device) 3 is a block diagram showing the control configuration of the recording device 101. The control section of the recording device 101 is mainly composed of a controller unit 301 that controls the entire recording device 101, and a print engine unit 302 that controls the recording section. A print controller 311 controls various mechanisms of the print engine unit 302 according to instructions from a main controller 304 of the controller unit 301.

[0034] In the first embodiment, the controller unit 301 includes an external I / F 303, a main controller 304, a ROM 305, a RAM 306, a print engine I / F 307, an operation unit 308, and an image processing unit 309. The print engine unit 302 includes a controller I / F 310, a print controller 311, a ROM 312, a RAM 313, and an image processing controller 314. The print engine unit 302 further includes a scanner control unit 315, a transport control unit 316, an ink supply control unit 317, a head carriage control unit 318, a head maintenance control unit 319, and a head I / F 320.

[0035] In the controller unit 301, a main controller 3 configured by a CPU Main controller 304 controls the entire recording device 101 using RAM 306 as a work area in accordance with programs and various parameters stored in ROM 305. For example, when a print job is input from an external host device via external I / F 303, image processing unit 309 performs predetermined image processing on the image data received in accordance with instructions from main controller 304. Then, main controller 304 transmits the image data that has been subjected to the image processing to print engine unit 302 via print engine I / F 307.

[0036] The means by which the recording device 101 acquires image data is not limited to the above. For example, image data may be acquired from another host device via wireless communication or wired communication. Also, image data may be acquired from an image reading device as an external device connected to the recording device 101 or an image reading device connected inside the device, or image data may be acquired from an external storage device (such as a USB memory) connected to the recording device 101. In this way, the means by which image data is acquired is not limited to communication means, connected external devices, etc.

[0037] An operation unit 308 is used to input and output data to and from the recording device, and can be used to instruct operations such as copying and scanning, set recording modes, and recognize information about the recording device.

[0038] In the print engine unit 302, a print controller 311 including a CPU and the like controls various mechanisms of the recording unit according to programs and various parameters stored in a ROM 312, using a RAM 313 as a work area. When various commands and image data are received via a controller I / F 310, the print controller 311 temporarily stores them in the RAM 313. The print controller 311 causes an image processing controller 314 to convert the stored image data into recording data so that the recording head 114 can use it for a recording operation. When the recording data is generated, the print controller 311 causes the recording head 114 to execute a recording operation based on the recording data via a head I / F 320. At this time, the print controller 311 drives a conveying unit of the recording device 101 via a conveying control unit 316 to convey a sheet. According to an instruction from the print controller 311, a recording operation is executed by the recording head 114 in conjunction with the sheet conveying operation, and recording processing is performed.

[0039] A head carriage control unit 318 changes the orientation and position of the print head 114 depending on the operating state, such as the maintenance state and printing state, of the printing apparatus 101. An ink supply control unit 317 controls the pressure and concentration of ink supplied to the print head 114 so that they fall within appropriate ranges. A head maintenance control unit 319 controls the operation of a cap unit and a wiping unit in the maintenance unit when performing a maintenance operation on the print head 114.

[0040] The control configuration of the recording device 101 is not limited to the above configuration. For example, the print controller 311 may control the mechanisms of the recording units, or each control unit may have a CPU, ROM, RAM, etc., and the print controller 311 may control only the entire device.

[0041] (Tension control configuration) 4 is a block diagram of the tension control configuration of the recording apparatus 101 in the first embodiment. The transport control unit 316 performs transport control in accordance with commands from the print controller 311 via a transport control I / F 401. The transport control unit 316 includes the transport control I / F 401, a transport unit 402, a recognition unit 403, a tension detection unit 106, a switching unit 405, a CPU 406, a ROM 411, and a RAM 412.

[0042] The CPU 406 includes a switching control unit 407, a comparison unit 408, a calculation unit 409, and a conveyance speed control unit 410. The conveyance control unit 316 controls the conveyance speed of the conveyance unit 402 by the conveyance speed control unit 410 of the CPU 406.

[0043] The ROM 411 stores a target tension Tt and a switching tension Ts for each type of sheet. The target tension Tt is an ideal tension value during sheet transport. The transport control unit 316 controls the sheet tension each time so that it approaches the target tension Tt. The switching tension Ts is a tension threshold value used when switching the sheet tension detection range.

[0044] The identification unit 403 is a sheet information acquisition unit used to identify the type of sheet and acquire sheet information including the type of sheet. The identification unit 403 determines the target tension Tt according to the type of sheet. In the first embodiment, when the sheet is conveyed, the target tension Tt determined for each type of sheet stored in the ROM 411 is set according to the identification result by the identification unit 403.

[0045] The tension detection unit 106 detects the tension of the sheet, and stores a tension detection value Td in the RAM 412. In the first embodiment, the tension detection range of the tension detection unit 106 is configured to be switchable based on the tension detection value Td stored in the RAM 412 and the switching tension Ts stored in the ROM 411.

[0046] The switching unit 405 is controlled by a switching control unit 407 of a CPU 406, and the tension detection range of the tension detection unit 106 is switched depending on the switching state of the switching unit 405. The switching control unit 407 performs switching control by comparing the switching tension Ts in a ROM 411 with the tension detection value Td acquired by the tension detection unit 404 using a comparison unit 408 of the ROM 411, and performs switching control depending on the result.

[0047] A calculation unit 409 of the CPU 406 compares the target tension Tt for each type of sheet stored in a ROM 411 with the tension detection value Td acquired by the tension detection unit 404 in a comparison unit 408, and calculates the conveying speed from the comparison result.

[0048] The detailed configuration of the switching unit 405 will be described with reference to FIG. 5. The switching unit 405 is composed of a first gain unit 451, a second gain unit 452, and an offset unit 453. The tension detection value Td is gain-adjusted by the first gain unit 451, or offset-corrected by the offset unit 453 and then gain-adjusted by the second gain unit 452. Then, based on the output value, the tension detection range is appropriately switched. In the first embodiment, the output value of the first gain unit 451 is 0 to 5V, the output value of the second gain unit 4521 is 0 to 10V, the output value of the offset unit 453 is 0 to 5V, and the output value of the tension detection unit 106 is 0 to 5mV. Also, the offset unit 453 performs offset correction of -5V.

[0049] (Tension detection method) Next, a tension detection method according to the first embodiment will be described. When detecting tension by the tension detection unit 106, a wider tension detection range allows the tension detection unit 106 to detect a wider range of tension, but the resolution is lower, making it difficult to obtain a tension value with high accuracy. However, if the tension detection range is narrowed in order to obtain a tension value with higher accuracy, the tension value cannot be obtained accurately if the tension value falls outside the tension detection range. Therefore, in the first embodiment, a switching tension Ts is provided as a threshold value, and the tension detection range is switched based on the tension detection value Td obtained each time by the tension detection unit 106.

[0050] The tension detection unit 106 according to the first embodiment is configured to be switchable between a first mode in which the tension detection range is a first detection range DR1 and a second mode in which the tension detection range is a second detection range DR2. More specifically, the tension detection unit 106 is switchable between the first mode and the second mode by the switching control unit 407 based on the tension detected by the tension detection unit 106.

[0051] The lower limit of the first detection range DR1 is a first lower limit value TL1, and the upper limit is a first upper limit value TU1. The lower limit of the second detection range DR2 is a second lower limit value TL2 that is larger than the first lower limit value TL1 and smaller than the first upper limit value TU1, and the upper limit is a second upper limit value TU2 that is larger than the first upper limit value TU1. That is, an overlapping region VDR is provided between the first detection range DR1 and the second detection range DR2, where the tension detection ranges overlap. The upper limit of the overlapping region VDR is the first upper limit value TU1, and the lower limit is the second lower limit value TL2.

[0052] FIG. 6 shows a tension detection characteristic diagram according to the first embodiment. The tension detection characteristic diagram is a graph in which the vertical axis indicates tension [N] and the horizontal axis indicates time [s]. FIG. 6 shows the target tension Tt and the switching tension Ts when the sheet is not a film. FIG. 6 also shows the overlapping region VDR by etching. In the first embodiment, the target tension Tt when the sheet is not a film is a value within the second detection range DR2, and is set to a value greater than the first upper limit value TU1. Also, the switching tension Ts is a value within the range of the overlapping region VDR.

[0053] 6, a method will be described in which, from a state in which the recording apparatus 101 is stopped, sheet conveyance is started and the tension is gradually increased to approach the target tension Tt. The left side of Fig. 6 shows the transition of the tension when the sheet tension is adjusted from a state in which the tension is 0 to the target tension Tt.

[0054] In the initial setting, the tension detection unit 106 is set to the first mode and detects tension within the first detection range DR1. When the first conveying roller pair 104 and the second conveying roller pair 110 start to be driven and the sheet starts to be conveyed, the tension of the sheet gradually increases with an increase in the rotation speed of the rollers of the first conveying roller pair 104 and the second conveying roller pair 110, i.e., an increase in the sheet conveying speed. During the sheet conveyance, the tension detection unit 106 continues to acquire the tension detection value Td at least until the tension becomes equal to the target tension Tt. Then, when the tension detection value Td becomes equal to or greater than the switching tension Ts, the CPU 406 (switching control unit 407) controls the switching unit 405 to switch the tension detection range from the first detection range DR1 to the second detection range DR2. In this way, the tension detection unit 106 is switched from the first mode to the second mode.

[0055] In the first embodiment, there is an overlapping area VDR between the first detection range DR1 and the second detection range DR2. This setting prevents the tension detection value Td from going outside the first detection range DR1 during switching of the tension detection range, and prevents the tension detection value Td from being detected normally. In FIG. 6, a switching time Sp1 is shown as the time required for switching the tension detection range. The switching time Sp1 is the time required for the tension to change from the switching tension Ts to the first upper limit value TU1.

[0056] When the tension detection value Td reaches the target tension Tt, the increase in tension is stopped and the tension is maintained at the target tension Tt. In this way, in the first embodiment, tension control is performed such that the tension detection range is switched while the tension is increasing.

[0057] Next, a method of gradually decreasing the tension of a sheet and stopping the conveyance while the sheet is being conveyed by the recording device 101 will be described with reference to Fig. 6. The right side of Fig. 6 shows the transition of the tension when the sheet tension is adjusted from the target tension Tt to 0.

[0058] When the sheet tension is the target tension Tt, the tension detection unit 106 is set in the second mode and detects the tension within the second detection range DR2. When the rotation speed of the rollers of the first conveying roller pair 104 and the second conveying roller pair 110 is gradually reduced, the sheet tension gradually decreases. In the sheet stopping operation, the tension detection unit 106 continues to acquire the tension detection value Td until the tension becomes 0. Then, when the tension detection value Td becomes equal to or less than the switching tension Ts, the CPU 406 (switching control unit 407) controls the switching unit 405 to switch the tension detection range from the second detection range DR2 to the first detection range DR1. In this way, the tension detection unit 106 is switched from the second mode to the first mode.

[0059] As described above, there is an overlapping area VDR between the first detection range DR1 and the second detection range DR2. This setting prevents the tension detection value Td from falling outside the second detection range DR2 during switching of the tension detection range, causing a period of time during which the tension detection value Td is not detected normally. In FIG. 6, a switching time Sp2 is shown as the time required for switching the tension detection range. The switching time Sp2 is the time required for the tension to change from the switching tension Ts to the second lower limit value TL2.

[0060] When the tension detection value Td becomes 0, the decrease in tension is stopped and the conveyance of the sheet is stopped. In this manner, in the first embodiment, tension control is executed such that the tension detection range is switched while the tension is decreasing.

[0061] Thus, in the first embodiment, in both cases where the sheet tension is gradually increased and decreased, the tension detection range of the tension detection unit 106 is switched based on the switching tension Ts to detect the tension. That is, according to the configuration of the first embodiment, even when performing tension control for a sheet with a large target tension Tt, the single tension detection unit 106 can detect tension from 0 to the target tension Tt with high accuracy. Therefore, according to the configuration of the first embodiment, tension control can be performed with high accuracy with a simple configuration.

[0062] Although the above-mentioned operation example was for a case where the sheet was not a film, for example, for a sheet that does not require strong tension such as a film, the target tension Tt may be set smaller than the switching tension Ts. In the first embodiment, the target tension Tt for the film is set smaller than the switching tension Ts, and the tension detection range is not switched during film tension control.

[0063] (Tension control method) Next, a tension control method in the recording apparatus 101 will be described. First, a tension control method for increasing the sheet tension from 0 to a target tension Tt will be described with reference to Fig. 7. Fig. 7 shows a flowchart of tension control at the start of sheet conveyance according to the first embodiment. In the first embodiment, the sheet tension control is performed by the CPU 406 of the conveyance control unit 316.

[0064] In controlling the tension of the sheet, first, in step S501, the type of the sheet (transport medium) is identified. Next, in step S502, it is determined whether the sheet is a film. If the sheet is a film (YES in S502), the process proceeds to step S503, where 0 is substituted into Flag, and Flag=0 is set. On the other hand, if the sheet is If the sheet is not a film (NO in S502), the process proceeds to step S504, where 1 is substituted into the flag, and Flag=1 is set. The flag is used in a later step to determine whether or not to switch the tension detection range. In the first embodiment, Flag=0 indicates that the sheet is a film, and Flag=1 indicates that the sheet is a transport medium other than a film.

[0065] After a value is assigned to Flag in step S503 or step S504, the process proceeds to step S505, where SW is set to 0. SW is used to set the tension detection range. In the first embodiment, when SW=0, the tension detection unit 106 is in the first mode, and the tension detection range is set to the first detection range DR1. When SW=1, the tension detection unit 106 is in the second mode, and the tension detection range is set to the second detection range DR2. That is, in step S505, first, as an initial setting, the tension detection unit 106 is in the first mode, and the tension detection range is set to the first detection range DR1.

[0066] After SW=0 is set in step S505, sheet conveyance is started in step S506. After sheet conveyance is started, the latest tension detection value Td is compared with the target tension Tt in step S507, and it is determined whether the tension detection value Td is less than the target tension Tt.

[0067] If Tt≦Td (NO in S507), the process proceeds to step S512 to reduce the tension, and the sheet conveying speed is reduced. Note that if the tension detection value Td is equal to the target tension Tt, tension control ends in the following step S513, so in principle Td=Tt does not occur when it is determined in step S507. After step S512, the process proceeds to step S513.

[0068] If Tt>Td (YES in S507), a process for increasing the tension is performed. Specifically, first, in step S508, it is determined whether or not Flag=0.

[0069] If Flag=0 (YES in S508), the process proceeds to step S511, where the conveying speed is increased. At this time, the sheet is a film, and the target tension Tt is set lower than the switching tension Ts. Therefore, since there is no need to switch the tension detection range of the tension detection unit 106, the conveying speed is increased in step S511 without comparing the tension detection value Td with the switching tension Ts.

[0070] If Flag=0 is not true (NO in S508), the process proceeds to step S509, where it is determined whether or not the tension detection value Td is equal to or greater than the switching tension Ts.

[0071] If Ts>Td (NO in S509), the process proceeds to step S511, where the conveying speed is increased. That is, the conveying speed is increased in step S511 while the tension detection range remains set to the first detection range DR1. At this time, although the sheet is not a film, tension control continues while the tension detection range remains the first detection range DR1, because the tension is still small.

[0072] If Ts≦Td (YES in S509), the process proceeds to step S510, where SW=1 is set. Then, the tension detection unit 106 is switched from the first mode to the second mode, and the tension detection range is set from the first detection range DR1 to the second detection range DR2. At this time, since the sheet is other than the film and the target tension Tt is set to be greater than the switching tension Ts, and the tension detection value Td is approaching the first upper limit value TU1 of the first detection range DR1, the tension detection range is switched to the second detection range DR2. Then, in step S510, The process proceeds from step S510 to step S511, where the conveying speed is increased.

[0073] After the conveying speed is increased in step S511 or decreased in step S512, the process proceeds to step S513. In step S513, a new tension detection value Td is acquired, and it is determined whether or not the tension detection value Td has reached the target tension Tt. If Tt=Td is not true (NO in S513), the process proceeds again to step S507, and tension control continues. Then, the operations from step S507 to step S513 are repeatedly executed until the tension detection value Td reaches the target tension Tt. On the other hand, if Tt=Td is true (YES in S513), it is determined that the tension has reached the target tension Tt, and tension control ends.

[0074] With this configuration, when controlling to gradually increase the tension of a sheet having a relatively high target tension Tt, the tension detection range is switched from the second detection range DR2 to the first detection range DR1 when the tension detection value Td becomes equal to or greater than a predetermined threshold value. Therefore, with the configuration of the first embodiment, the sheet tension can be detected with high resolution at all times.

[0075] In tension control, it is not necessary to perform all steps as described above, and the execution contents and execution order of each step can be changed as appropriate. For example, if it is determined that Flag=0 in step S508, the operation of the subsequent step S508 may be omitted, and the process may proceed directly from step S507 to step S511. Also, for example, if SW=1 is set once in step S510, the operations from step S508 to step S510 may be omitted, and only the operations of steps S507, S511 (S512), and S513 may be repeated. In the above control example, the tension control is terminated when Tt=Td, but the tension control may be terminated when the difference between the tension detection value Td and the target tension Tt becomes equal to or less than a predetermined value.

[0076] Next, a tension control method for lowering the sheet tension to 0 will be described with reference to Fig. 8. Fig. 8 shows a flowchart of tension control when the sheet conveyance is stopped according to the first embodiment. Even when the tension is lowered, the CPU 406 of the conveyance control unit 316 controls the sheet tension.

[0077] When the conveyance of the sheet is stopped, first, in step S601, it is determined whether or not the tension detection value Td is 0. If Td=0 (YES in S601), the conveyance of the sheet is stopped and the tension control is also ended.

[0078] If Td=0 is not true (NO in S601), the process proceeds to step S602, where it is determined whether Flag=0 is true.

[0079] When Flag = 0 (YES in S602), the process proceeds to step S605 and the conveyance speed is decreased. At this time, since the sheet is a film, the tension detection unit 106 is set in the first mode, and the tension detection range is the first detection range DR1. When the sheet is a film, there is no need to switch the tension detection range of the tension detection unit 106, and the conveyance speed is decreased in step S605 without comparing the tension detection value Td with the switching tension Ts.

[0080] When Flag ≠ 0 (NO in S602), the process proceeds to step S603, and it is determined whether the tension detection value Td is less than or equal to the switching tension Ts. When the sheet is other than a film, when starting the conveyance stop control of the sheet, the tension detection unit 106 is set in the second mode, and the tension detection range is the second detection range DR2. Therefore, it is determined by comparing the tension detection value Td with the switching tension Ts whether it is necessary to switch the tension detection range of the tension detection unit 106.

[0081] When Ts < Td (NO in S603), the process proceeds to step S605 and the conveyance speed is decreased. That is, the conveyance speed is decreased in step S605 while the tension detection range remains set to the second detection range DR2.

[0082] When Ts ≥ Td (YES in S603), the process proceeds to step S604 and SW = 0 is set. Then, the tension detection unit 106 is switched from the second mode to the first mode, and the tension detection range is set from the second detection range DR2 to the first detection range DR1. At this time, since the sheet is other than a film, the target tension Tt is set larger than the switching tension Ts, and the tension detection value Td is approaching the second lower limit value TL2 of the second detection range DR2, the tension detection range is switched to the first detection range DR1. Then, the process proceeds from step S604 to step S605 and the conveyance speed is increased.

[0083] If the conveying speed is reduced in step S605, the process returns to step S601. Then, the operations from step S601 to step S605 are repeatedly executed until the tension detection value Td becomes 0.

[0084] With this configuration, when controlling to gradually reduce the tension of a sheet having a relatively high target tension Tt, the tension detection range is switched from the second detection range DR2 to the first detection range DR1 when the tension detection value Td becomes equal to or less than a predetermined threshold value. Therefore, with the configuration of the first embodiment, the sheet tension can be detected with high resolution at all times.

[0085] In tension control, it is not necessary that all steps are performed as described above, and the execution content and execution order of each step can be changed as appropriate. For example, once SW=0 is set in step S604, the operations of subsequent steps S603 and S604 may be omitted. In the above control example, the tension is set to 0, but the tension can be controlled in the same manner as in the above control example when lowering the tension to a predetermined target value.

[0086] In this way, according to the configuration of the first embodiment, tension control is performed while the tension detection range is appropriately switched according to the tension of the sheet. In the first embodiment, when a conveyed medium whose target tension Tt set according to the type of sheet is smaller than the second lower limit value TL2 is used, the tension detection unit 106 always detects the tension within the first detection range DR1. On the other hand, when a conveyed medium whose target tension Tt is larger than the second lower limit value TL2 is used, the tension detection range is switched from the first detection range DR1 to the second detection range DR2 when the tension is gradually increased. Also, when a conveyed medium whose target tension Tt is larger than the second lower limit value TL2 is used, the tension detection range is switched from the second detection range DR2 to the first detection range DR1 when the tension is gradually decreased.

[0087] As described above, according to the configuration of the first embodiment, in both cases where the sheet tension is gradually increased and decreased, the tension detection range of the tension detection unit 106 can be switched according to the type of sheet and the tension detection value Td. In other words, since the tension can be controlled while always being detected with high resolution and high accuracy, it is possible to suppress the occurrence of sheet stretching and bending, and to suppress sheet conveyance failure. Furthermore, it is possible to suppress image quality degradation caused by sheet conveyance failure.

[0088] In the first embodiment, the target tension Tt is set individually according to sheet information such as the type of sheet, but the switching tension Ts and the tension detection area may be set individually according to the sheet information. For example, the first upper limit value TU1, the first lower limit value TL1, the second upper limit value TU2, the second lower limit value TL2, and the switching tension Ts may be determined individually for each predetermined sheet information. By configuring the tension detection range to be switched according to the sheet information including the thickness and material of the sheet and the tension detection value Td, it is possible to detect and control the tension with higher accuracy. In the first embodiment, the control to increase the tension of the sheet and the control to decrease the tension of the sheet are distinguished as separate controls, but they may be collectively performed as one tension control from the start of conveying the sheet to the stop of conveying the sheet of the recording device 101.

[0089] <Second Example> Next, a second embodiment of the present invention will be described. The second embodiment differs from the first embodiment in that two switching tensions are set for switching the tension detection range. By providing two switching tensions for the tension detection range, it is possible to reduce overlapping areas of the tension detection range and improve the tension detection accuracy. Below, only the differences between the configuration of the second embodiment and the configuration of the first embodiment will be described. The same reference numerals will be used for the same parts of the configuration of the second embodiment as those of the first embodiment, and the description will be omitted.

[0090] (Tension detection method) A tension detection method according to the second embodiment will be described. The tension detection unit 106 according to the second embodiment is configured to be switchable between a first mode in which the tension detection range is a first detection range DR1, and a second mode in which the tension detection range is a second detection range DR2. More specifically, the tension detection unit 106 can switch between the first mode and the second mode by the switching control unit 407 based on the tension detected by the tension detection unit 106.

[0091] The lower limit of the first detection range DR1 is a first lower limit value TL1, and the upper limit is a first upper limit value TU1. The lower limit of the second detection range DR2 is a second lower limit value TL2 that is larger than the first lower limit value TL1 and smaller than the first upper limit value TU1, and the upper limit is a second upper limit value TU2 that is larger than the first upper limit value TU1. That is, the first detection range DR1 and the second detection range DR2 have an overlapping region VDR where the tension detection ranges overlap.

[0092] In the second embodiment, a first switching tension Ts1, which is a first threshold, and a second switching tension Ts2, which is a second threshold, are set as the tension thresholds used when switching the tension detection range. The first switching tension Ts1 is the same value as the second lower limit value TL2 of the second detection range DR2, and the second switching tension Ts2 is the same value as the first upper limit value TU1 of the first detection range DR1 and is greater than the first switching tension Ts1. That is, the upper limit value of the overlapping region VDR in the second embodiment is the second switching tension Ts2, and the lower limit value is the first switching tension Ts1. Therefore, the range of the overlapping region VDR in the second embodiment is narrower than the overlapping region VDR in the first embodiment.

[0093] In the second embodiment, since there is an overlapping region VDR, it is possible to prevent the tension detection value Td from going out of the tension detection range during switching of the tension detection range, and to prevent the occurrence of a time during which the tension detection value Td is not detected normally. In Fig. 9, switching times Sp1 and SP2 are shown as times for switching the tension detection range. The switching time Sp1 is the time until the tension changes from the first switching tension Ts1 to the first upper limit value TU1. The switching time Sp2 is the time until the tension changes from the second switching tension Ts2 to the second lower limit value TL2.

[0094] FIG. 9 shows a tension detection characteristic diagram according to the second embodiment. The graph shows tension [N] on the axis and time [s] on the horizontal axis. Fig. 9 shows the target tension Tt, the first switching tension Ts1, and the second switching tension Ts2 when the sheet is not a film. Fig. 9 also shows the overlapping region VDR by etching. In the second embodiment, the target tension Tt when the sheet is not a film is set to a value within the second detection range DR2 and greater than the first upper limit value TU1.

[0095] 9, a method will be described in which, from a state in which the recording apparatus 101 is stopped, sheet conveyance is started and the tension is gradually increased to approach the target tension Tt. The left side of Fig. 9 shows the transition of the tension when the sheet tension is adjusted from a state in which the tension is 0 to the target tension Tt.

[0096] In the initial setting, the tension detection unit 106 is set to the first mode and detects tension within a first detection range DR1. When sheet conveyance is started, the tension of the sheet gradually increases as the sheet conveyance speed increases. In the second embodiment, when the tension detection value Td becomes equal to or greater than the first switching tension Ts1, the CPU 406 (switching control unit 407) controls the switching unit 405 to switch the tension detection range from the first detection range DR1 to the second detection range DR2. In this way, the tension detection unit 106 is switched from the first mode to the second mode. Then, when the tension detection value Td reaches the target tension Tt, the increase in tension is stopped and the tension is maintained at the target tension Tt.

[0097] Next, a method of gradually decreasing the tension of a sheet and stopping the conveyance while the sheet is being conveyed by the recording device 101 will be described with reference to Fig. 9. The right side of Fig. 9 shows the transition of the tension when the sheet tension is adjusted from the target tension Tt to 0.

[0098] When the sheet tension is the target tension Tt, the tension detection unit 106 is set in the second mode and detects the tension within the second detection range DR2. When the sheet conveying speed is gradually reduced, the sheet tension is gradually reduced. In the second embodiment, when the tension detection value Td becomes equal to or less than the second switching tension Ts2, the CPU 406 (switching control unit 407) controls the switching unit 405 to switch the tension detection range from the second detection range DR2 to the first detection range DR1. In this way, the tension detection unit 106 is switched from the second mode to the first mode. Then, when the tension detection value Td becomes 0, the reduction in tension is stopped and the conveyance of the sheet is stopped.

[0099] In this way, in the second embodiment, the tension detection range of the tension detection unit 106 is switched based on the switching tension Ts in both cases where the sheet tension is gradually increased and decreased, and the tension is detected. Furthermore, in the second embodiment, the overlapping area VDR of the first detection range DR1 and the second detection range DR2 can be set narrower than in the first embodiment. Therefore, it is possible to set the ranges of the first detection range DR1 and the second detection range DR2 narrower, and the resolution in each detection range can be further improved. Furthermore, since the tension can be detected and controlled with high accuracy, sheet conveyance failure can be suppressed.

[0100] (Tension control method) Next, a tension control method for the recording device 101 according to the second embodiment will be described. Since the tension control method according to the second embodiment has many overlapping parts with the tension control method according to the first embodiment, a description of the overlapping parts will be omitted and the description will focus on the differences.

[0101] First, a tension control method for increasing the sheet tension from 0 to a target tension Tt will be described with reference to Fig. 10. Fig. 10 shows a state where the sheet conveyance is started in the second embodiment. 13 shows a flowchart of tension control in the second embodiment. In the second embodiment, the tension control of the sheet is performed by the CPU 406 of the conveyance control unit 316.

[0102] The process from step S801 to step S806 is the same as the process from step S501 to step S506 in the first embodiment. That is, in controlling the tension of the sheet, the type of the sheet is identified (S801), the type of the sheet is determined (S802), a value is assigned to Flag (S803, S804), SW=0 is set (S805), and conveyance of the sheet is started (S806).

[0103] Furthermore, steps S807 to S813 are generally similar to steps S507 to S513 in the first embodiment. Of these steps, the second embodiment differs from the first embodiment in that the threshold value compared with the tension detection value Td in step S809 is the first switch tension Ts1. That is, while the tension detection value Td is smaller than the first switch tension Ts1, the tension in the second embodiment is controlled in the same way as in the first embodiment.

[0104] If it is determined in step S807 that Tt≦Td (NO in S807), the flow proceeds to step S812 where the sheet conveying speed is reduced in order to reduce the tension, and then in step S813 it is determined whether or not to end the tension control.

[0105] In step S807, if it is determined that Tt>Td (YES in S807), and Flag=0 and the sheet is a film (YES in S808), the process proceeds to step S811, where the sheet conveying speed is increased. After that, in step S813, it is determined whether or not to end the tension control.

[0106] If it is determined in step 807 that Tt>Td (YES in S807), and Flag is not 0 and the sheet is not a film (NO in S808), the process proceeds to step S809. In step S809, it is determined whether the tension detection value Td is equal to or greater than the first switching tension Ts1. If Ts1>Td (NO in S809), the process proceeds to step S811 where the conveying speed is increased. If Ts1≦Td (YES in S809), the process proceeds to step S810 where SW=1 is set and the tension detection range is switched from the first detection range DR1 to the second detection range DR2. Thereafter, the process proceeds to step S811 where the conveying speed is increased, and it is determined in step S813 whether or not to end tension control.

[0107] In step S813, it is determined whether the newly obtained tension detection value Td has reached the target tension Tt, and the operations from step S807 to step S813 are repeatedly executed until the tension detection value Td reaches the target tension Tt.

[0108] Subsequently, referring to FIG. 11, a tension control method for lowering the tension of the sheet to 0 will be described. FIG. 11 shows a flowchart of the tension control when the sheet conveyance stops according to the second embodiment. Also during the tension reduction, the CPU 406 of the conveyance control unit 316 controls the tension of the sheet.

[0109] The steps from step S901 to step S905 are generally the same as the steps from step S601 to step S605 according to the first embodiment. Among these steps, the second embodiment is different from the first embodiment in that the threshold value compared with the tension detection value Td in step S903 is the second switching tension Ts2. That is, while the tension detection value Td is greater than the second switching tension Ts2, the tension in the second embodiment is controlled in the same manner as in the first embodiment.

[0110] The steps of step S901, S902, and S905 are the same as the steps of step S601, S602, and S605 according to the first embodiment, respectively. That is, when the sheet is a film, after determining whether the tension detection value Td is 0 (S901) and determining whether the sheet is a film (S902), the conveyance speed of the sheet is decreased (S905), and the process returns to step S901 again.

[0111] When the sheet is not a film (NO in S902), the process proceeds to step S903, and it is determined whether the tension detection value Td is less than or equal to the second switching tension Ts2. When Ts2 < Td (NO in S903), the process proceeds to step S905, the conveyance speed is decreased, and the process returns to step S901 again.

[0112] If Ts2≧Td (YES in S903), the process proceeds to step S904, where SW is set to 0, and the tension detection range is switched from the second detection range DR2 to the first detection range DR1. After that, the process proceeds to step S905, where the conveying speed is reduced, and the process proceeds to step S901 again.

[0113] In step S901, it is determined whether a newly acquired tension detection value Td has become 0, and the operations from step S901 to step S905 are repeatedly executed until the tension detection value Td becomes 0.

[0114] In this way, according to the configuration of the second embodiment, tension control is performed while the tension detection range is appropriately switched according to the tension of the sheet. In the second embodiment, when a conveyed medium whose target tension Tt set according to the type of sheet is smaller than the second lower limit value TL2 is used, the tension detection unit 106 always detects the tension within the first detection range DR1. On the other hand, when a conveyed medium whose target tension Tt is larger than the first upper limit value TU1 is used, the tension detection range is switched from the first detection range DR1 to the second detection range DR2 when the tension is gradually increased. Also, when a conveyed medium whose target tension Tt is larger than the first upper limit value TU1 is used, the tension detection range is switched from the second detection range DR2 to the first detection range DR1 when the tension is gradually decreased. Note that each detection range is set so that the target tension Tt of each conveyed medium is not located within the range of the overlapping region VDR.

[0115] As described above, according to the configuration of the second embodiment, in both cases where the sheet tension is gradually increased and gradually decreased, the tension detection range of the tension detection unit 106 can be switched according to the type of sheet and the tension detection value Td. Furthermore, compared to the first embodiment, the ranges of the first detection range DR1 and the second detection range DR2 can be set narrower, so that the tension can be detected and controlled with higher accuracy, and sheet conveyance failures can be suppressed.

[0116] <Third Example> Next, a third embodiment of the present invention will be described. The third embodiment differs from the first embodiment in that three types of tension detection ranges are provided, and four switching tensions are set for switching the tension detection ranges. By increasing the number of tension detection ranges, it is possible to reduce overlapping areas of the tension detection ranges and improve the tension detection accuracy. Below, only the differences between the configuration of the third embodiment and the configuration of the first embodiment will be described. The same reference numerals are used for the same parts of the configuration of the third embodiment as those of the first embodiment, and the description will be omitted.

[0117] (Tension detection method) A tension detection method according to the third embodiment will be described. The detection unit 106 is configured to be switchable between a first mode in which the tension detection range is a first detection range DR1, a second mode in which the tension detection range is a second detection range DR2, and a third mode in which the tension detection range is a third detection range DR3. More specifically, the tension detection unit 106 can be switched between the first mode and the second mode by the switching control unit 407 based on the tension detected by the tension detection unit 106. Furthermore, the tension detection unit 106 can be switched between the second mode and the third mode by the switching control unit 407 based on the tension detected by the tension detection unit 106.

[0118] The lower limit of the first detection range DR1 is a first lower limit value TL1, and the upper limit is a first upper limit value TU1. The lower limit of the second detection range DR2 is a second lower limit value TL2 that is greater than the first lower limit value TL1 and less than the first upper limit value TU1, and the upper limit is a second upper limit value TU2 that is greater than the first upper limit value TU1. The lower limit of the third detection range DR3 is a third lower limit value TL3 that is greater than the first upper limit value TU1 and the second lower limit value TL2 and less than the second upper limit value TU2, and the upper limit is a third upper limit value TU3 that is greater than the second upper limit value TU2.

[0119] The first detection range DR1 and the second detection range DR2 have a first overlapping area VDR1 where the tension detection ranges overlap. The upper limit of the overlapping area VDR is a first upper limit value TU1, and the lower limit is a second lower limit value TL2. The second detection range DR2 and the third detection range DR3 have a second overlapping area VDR2 where the tension detection ranges overlap. The upper limit of the overlapping area VDR is a second upper limit value TU2, and the lower limit is a third lower limit value TL3.

[0120] In the third embodiment, since the first overlapping area VDR1 and the second overlapping area VDR2 exist, the tension detection value Td does not fall outside the tension detection range during switching of the tension detection range, and a time during which the tension detection value Td is not detected normally is prevented from occurring. FIG. 12 shows switching times Sp1, SP2, SP3, and SP4 as times for switching the tension detection range. The switching time Sp1 is the time until the tension changes from the first switching tension Ts1 to the first upper limit value TU1. The switching time Sp2 is the time until the tension changes from the second switching tension Ts2 to the second lower limit value TL2. The switching time Sp3 is the time until the tension changes from the third switching tension Ts3 to the second upper limit value TU2. The switching time Sp4 is the time until the tension changes from the fourth switching tension Ts4 to the third lower limit value TL3.

[0121] In the third embodiment, four thresholds are set as the tension thresholds used when switching the tension detection range. Specifically, a first switching tension Ts1 as the first threshold, a second switching tension Ts2 as the second threshold, a third switching tension Ts3 as the third threshold, and a fourth switching tension Ts4 as the fourth threshold are set. The first switching tension Ts1 is the same value as the second lower limit value TL2 of the second detection range DR2, and the second switching tension Ts2 is the same value as the first upper limit value TU1 of the first detection range DR1 and is larger than the first switching tension Ts1. The third switching tension Ts3 is the same value as the third lower limit value TL3 of the third detection range DR3, and the fourth switching tension Ts4 is the same value as the second upper limit value TU2 of the second detection range DR2 and is larger than the third switching tension Ts3. That is, the upper limit value of the first overlapping region VDR1 according to the third embodiment is the second switching tension Ts2, and the lower limit value is the first switching tension Ts1. In addition, the upper limit value of the second overlap region VDR2 is the fourth switch tension Ts4, and the lower limit value is the third switch tension Ts3.

[0122] Fig. 12 shows a tension detection characteristic diagram according to the third embodiment. The tension detection characteristic diagram is a graph in which the vertical axis indicates tension [N] and the horizontal axis indicates time [s]. Fig. 12 shows the target tension Tt when the sheet has the highest target tension Tt among the selectable sheet types. Fig. 12 also shows a first switch tension Ts1, a second switch tension Ts2, a third switch tension Ts3, and a fourth switch tension Ts4, and the first overlap The region VDR1 and the second overlap region VDR2 are indicated by etching. In the case of this control example, the target tension Tt is set to a value within the third detection range DR3 and greater than the second upper limit value TU2.

[0123] 12, a method will be described in which, from a state in which the recording apparatus 101 is stopped, sheet conveyance is started and the tension is gradually increased to approach the target tension Tt. The left side of Fig. 12 shows the transition of the tension when the sheet tension is adjusted from a state in which the tension is 0 to the target tension Tt.

[0124] In the initial setting, the tension detection unit 106 is set to the first mode and detects tension within a first detection range DR1. When sheet conveyance is started, the sheet tension gradually increases as the sheet conveyance speed increases. In the third embodiment, when the tension detection value Td becomes equal to or greater than the first switching tension Ts1, the CPU 406 (switching control unit 407) controls the switching unit 405 to switch the tension detection range from the first detection range DR1 to the second detection range DR2. In this way, the tension detection unit 106 is switched from the first mode to the second mode.

[0125] With the tension detection unit 106 in the second mode, tension control continues, and when the tension detection value Td becomes equal to or greater than the third switching tension Ts3, the tension detection range is switched from the second detection range to the third detection range DR3. Then, the tension detection unit 106 is switched from the second mode to the third mode. Thereafter, tension control continues with the tension detection unit 106 in the third mode, and when the tension detection value Td reaches the target tension Tt, the increase in tension is stopped and the tension is maintained at the target tension Tt.

[0126] Next, a method of gradually decreasing the tension of a sheet and stopping the conveyance while the sheet is being conveyed by the recording device 101 will be described with reference to Fig. 12. The right side of Fig. 12 shows the transition of the tension when the tension of the sheet is adjusted from the target tension Tt to 0.

[0127] When the sheet tension is the target tension Tt, the tension detection unit 106 is set in the third mode and detects the tension within the third detection range DR3. When the sheet conveying speed is gradually reduced, the sheet tension is gradually reduced. In the third embodiment, when the tension detection value Td becomes equal to or less than the fourth switching tension Ts4, the CPU 406 (switching control unit 407) controls the switching unit 405 to switch the tension detection range from the third detection range DR3 to the second detection range DR2. In this way, the tension detection unit 106 is switched from the third mode to the second mode.

[0128] Tension control continues with the tension detection unit 106 in the third mode, and when the tension detection value Td becomes equal to or less than the second switching tension Ts2, the tension detection range is switched from the second detection range to the first detection range DR1. Then, the tension detection unit 106 is switched from the second mode to the first mode. Then, tension control continues thereafter with the tension detection unit 106 in the first mode, and when the tension detection value Td becomes 0, the reduction in tension is stopped and the conveyance of the sheet is stopped.

[0129] In this way, in the third embodiment, the tension detection range is divided into a greater number of ranges than in the first embodiment, and therefore the resolution in each detection range is increased. As a result, tension can be detected and controlled with higher accuracy, and therefore stretching or bending of the sheet can be suppressed, thereby suppressing sheet conveyance problems.

[0130] (Tension control method) Next, a description will be given of a tension control method in the recording device 101. The tension control method according to the third embodiment has many overlapping parts with the tension control method according to the first embodiment, so a description of the overlapping parts will be omitted and the description will focus on the differences.

[0131] First, a tension control method for increasing the sheet tension from 0 to a target tension Tt will be described with reference to Fig. 13. Fig. 13 shows a flowchart of tension control at the start of sheet conveyance according to the third embodiment. In the third embodiment, the sheet tension control is performed by the CPU 406 of the conveyance control unit 316.

[0132] Steps S1101, S1102, and S1104 are the same as steps S501, S502, and S503 in Example 1. That is, in controlling the tension of the sheet, first, the type of the sheet is identified (S1101), and it is determined whether the sheet is a film or not (S1102). If the sheet is a film, 0 is substituted into Flag, and Flag=0 is set (S1104).

[0133] If the sheet is not a film (NO in S1102), the process proceeds to step S1103, where it is determined whether the sheet is cardboard. In the third embodiment, the detection ranges are set so that the target tension Tt for cardboard is greater than the second upper limit value TU2 of the second detection range DR2, and the target tension Tt for sheets other than film and cardboard is a value within the range of the second detection range DR2.

[0134] If the sheet is a film (YES in S1103), the process proceeds to step S1105, where 2 is assigned to Flag, and Flag = 2. On the other hand, if the sheet is not cardboard (NO in S1103), the process proceeds to step S1106, where 1 is assigned to Flag, and Flag = 1. In the third embodiment, Flag = 0 indicates that the sheet is a film, Flag = 1 indicates that the sheet is a transport medium other than film or cardboard, and Flag = 2 indicates that the sheet is cardboard.

[0135] After a value is assigned to the Flag in any one of steps S1104, S1105, and S1106, the process proceeds to step S1107. Steps S1107 to S1109 are the same as steps S505 to S507 in the first embodiment. That is, setting SW=0 (S1107), starting sheet conveyance (S1108), and determining whether the tension detection value Td is less than the target tension Tt (S1109) are performed. In the third embodiment, when SW=0, the tension detection unit 106 is in the first mode, and the tension detection range is set to the first detection range DR1. When SW=1, the tension detection unit 106 is in the second mode, and the tension detection range is set to the second detection range DR2, and when SW=2, the tension detection unit 106 is in the third mode, and the tension detection range is set to the third detection range DR3.

[0136] If it is determined in step S1109 that Tt≦Td (NO in S1109), the flow proceeds to step S1117 to reduce the sheet conveying speed in order to reduce the tension, and then in step S1118 it is determined whether or not to end the tension control.

[0137] If it is determined in step S1109 that Tt>Td (YES in S1109), the process proceeds to step S1110, where it is determined whether Flag=0, that is, whether the sheet is a film. If Flag=0 and the sheet is a film (YES in S1110), the process proceeds to step S1116, where the sheet conveying speed is increased.

[0138] On the other hand, if Flag=0 and the sheet is not a film (NO in S1110), step The process proceeds to step S1111, where it is determined whether the tension detection value Td is equal to or greater than the first switch tension Ts1.

[0139] If Ts1>Td (NO in S1111), the process proceeds to step S1116, where the conveying speed is increased. That is, tension control continues with the tension detection unit 106 in the first mode and the tension detection range being the first detection range DR1.

[0140] If Ts1≦Td (YES in S1111), the process proceeds to step S1112, where it is determined whether Flag=1, that is, whether the sheet is a conveying medium other than film or cardboard.

[0141] If Flag=1 (YES in S1112), the sheet is a conveying medium other than film or cardboard, and the process proceeds to step S1114, where SW=1 is set. Then, the tension detection unit 106 is switched from the first mode to the second mode, and the tension detection range is set from the first detection range DR1 to the second detection range DR2. After that, the process proceeds from step S1114 to step S1116, and the conveying speed is increased. In this case, the tension control thereafter is performed with the tension detection unit 106 in the second mode and the tension detection range in the second detection range DR2.

[0142] If Flag=1 is not true (NO in S1112), the sheet is thick paper, so the process proceeds to step S1113, where it is determined whether the tension detection value Td is equal to or greater than the third switch tension Ts3.

[0143] If Ts3>Td (NO in S1113), the process proceeds to step S1114, where SW is set to 1, and the process proceeds to step S1116, where the conveying speed is increased. In this case, the tension detection unit 106 is in the second mode, and the tension detection range is the second detection range DR2, and the subsequent tension control is performed.

[0144] If Ts3≦Td (YES in S1113), the process proceeds to step S1115, where SW is set to 2. Then, the tension detection unit 106 is switched to the third mode, and the tension detection range is set to the third detection range DR3. After that, the process proceeds from step S1115 to step S1116, and the conveying speed is increased. In this case, the subsequent tension control is performed with the tension detection unit 106 in the third mode and the tension detection range in the third detection range DR3.

[0145] After the conveying speed is increased in step S1116 or decreased in step S1117, the process proceeds to step S1118. The process of step S1118 is similar to the process of step S513 in the first embodiment. Then, the operations from step S1109 to step S1118 are repeatedly executed until the tension detection value Td becomes the target tension Tt.

[0146] In tension control, it is not necessary that all steps are performed as described above, and the execution content and order of each step can be changed as appropriate. For example, once it is determined that Flag=0 in step S1110 or once it is determined that Flag=1 in step S1112, the operations of the following steps S1110 and S1112 may be omitted. Also, for example, once SW=2 is set in step S1115, the operations from step S1110 to step S1115 may be omitted, and only the operations of steps S1110, S1116 (S1117), and S1118 may be repeated. Also, in the above control example, tension control was terminated when Tt=Td, but it may be terminated when the difference between the tension detection value Td and the target tension Tt falls below a predetermined value. If this occurs, the tension control may be terminated.

[0147] Next, referring to FIG. 14, a tension control method for reducing the tension of the sheet to 0 will be described. FIG. 14 shows a flowchart of tension control when the sheet conveyance stops according to the third embodiment. Even when the tension is decreasing, the CPU 406 of the conveyance control unit 316 controls the tension of the sheet.

[0148] The steps of steps S1201, S1202, and S1208 are the same as the steps of steps S601, S602, and S605 according to the first embodiment, respectively. That is, when the sheet is a film, it is determined whether the tension detection value Td is 0 (S1201), and after determining whether the sheet is a film (S1202), the conveyance speed of the sheet is decreased (S1208), and the process returns to step S1201 again.

[0149] If Flag≠0 (NO in S1202), the sheet is a conveyance medium other than a film, and the process proceeds to step S1203 to determine whether the tension detection value Td is less than or equal to the fourth switching tension Ts4. If Ts4 < Td (NO in S1203), the process proceeds to step S1208 to decrease the conveyance speed, and then returns to step S1201 again.

[0150] If Ts4≥Td (YES in S1203), the process proceeds to step S1204 to determine whether the tension detection value Td is less than or equal to the second switching tension Ts2.

[0151] If Ts2≥Td (YES in S1204), the process proceeds to step S1206 where SW = 0, and the tension detection range is switched to the first detection range DR1. At this time, regardless of whether the sheet is cardboard or a conveyance medium other than film and cardboard, the same processing is performed. Then, the process proceeds to step S1208 to decrease the conveyance speed, and then returns to step S1201 again.

[0152] If Ts2 < Td (NO in S1204), the process proceeds to step S1205 to determine whether Flag = 1, that is, whether the sheet is a conveyance medium other than film and cardboard.

[0153] If it is determined in step S1205 that Flag = 1 is not satisfied (NO in S1205), the sheet is cardboard (Flag = 2), and the tension detection value Td is within the range of Ts2 < Td ≤ Ts4. Therefore, the process proceeds to step S1207, where SW = 1 is set, and the tension detection range is switched to the second detection range DR2. Then, the process proceeds to step S1208, where the conveyance speed is decreased, and the process returns to step S1201 again.

[0154] On the other hand, if it is determined in step S1205 that Flag = 1 is satisfied (YES in S1205), the sheet is a conveyance medium other than film and cardboard, and the tension detection value Td is within the range of Ts2 < Td ≤ Ts4. In this case, the tension detection range is already the second detection range DR2 at the start of tension control. Therefore, thereafter, the process proceeds to step S1208, where the conveyance speed is decreased, and the process returns to step S1201 again.

[0155] In step S1201, it is determined whether the newly acquired tension detection value Td has become 0, and the operations from step S1201 to step S1208 are repeatedly executed until the tension detection value Td becomes 0.

[0156] Note that in tension control, it is not always necessary for all steps to be performed as described above, and the execution content and execution order of each step can be changed as appropriate. For example, After SW = 1 is set once in step S1205, the operations of subsequent step S1205 and step S1207 may be omitted.

[0157] In this way, according to the configuration of the third embodiment, tension control is performed while the tension detection range is appropriately switched according to the tension of the sheet. In the second embodiment, when a conveying medium whose target tension Tt set according to the type of sheet is smaller than the second lower limit value TL2 is used, the tension detection unit 106 always detects the tension within the first detection range DR1. On the other hand, when a conveying medium whose target tension Tt is larger than the first upper limit value TU1 and smaller than the third lower limit value TL3 is used, the tension detection range is switched from the first detection range DR1 to the second detection range DR2 when the tension is gradually increased. Also, when a conveying medium whose target tension Tt is larger than the first upper limit value TU1 and smaller than the third lower limit value TL3 is used, the tension detection range is switched from the second detection range DR2 to the first detection range DR1 when the tension is gradually decreased. Also, when a conveying medium whose target tension Tt is larger than the second upper limit value TU2 is used, the tension detection range is switched in the order of the first detection range DR1, the second detection range DR2, and the third detection range DR3 when the tension is gradually increased. Furthermore, when a conveyed medium with a target tension Tt greater than the second upper limit value TU2 is used and the tension is gradually reduced, the tension detection range is switched in the order of the third detection range DR3, the second detection range DR2, and the first detection range DR1. Note that each detection range is set so that the target tension Tt of each conveyed medium is not located within the range of the overlapping region VDR.

[0158] As described above, according to the configuration of the third embodiment, in both cases where the sheet tension is gradually increased and gradually decreased, the tension detection range of the tension detection unit 106 can be switched according to the type of sheet and the tension detection value Td. Furthermore, since the tension detection range is divided into a greater number of parts compared to the first embodiment, it is possible to detect and control the tension with higher accuracy and suppress sheet conveyance failure.

[0159] The disclosure of this embodiment includes the following configuration. (Configuration 1) a conveying unit that conveys the sheet while applying tension to the sheet along a conveying direction of the sheet; a tension detection unit that detects tension of the sheet being conveyed to the conveying unit; Equipped with the tension detection unit is configured to be switchable between a first mode capable of detecting tension between a first lower limit value and a first upper limit value, and a second mode capable of detecting tension between a second lower limit value larger than the first lower limit value and a second upper limit value larger than the first upper limit value, A conveying device comprising: a control unit that switches between the first mode and the second mode based on the tension detected by the tension detection unit. (Configuration 2) The conveying unit has a tension adjusting unit that adjusts the tension applied to the sheet, The control unit of the conveying device described in configuration 1 is characterized in that when the tension detection unit is in the first mode and the tension of the sheet is increased toward a target value by the tension adjustment means, when the tension detected by the tension detection unit becomes equal to or greater than a threshold value, the control unit switches the tension detection unit to the second mode. (Configuration 3) 3. The conveying device according to configuration 2, wherein the threshold value is greater than the second lower limit value and less than the first upper limit value. (Configuration 4) The conveying unit has a tension adjusting unit that adjusts the tension applied to the sheet, The control unit, when the control unit is in the second mode and the tension adjustment unit is used to reduce the tension of the sheet toward a target value, detects the tension detected by the tension detection unit. 4. The conveying device according to any one of configurations 1 to 3, wherein the tension detector switches to the first mode when the tension becomes equal to or lower than a threshold value. (Configuration 5) 5. The conveying device according to configuration 4, wherein the threshold value is greater than the second lower limit value and less than the first upper limit value. (Configuration 6) The conveying unit has a tension adjusting unit that adjusts the tension applied to the sheet, The control unit is when the tension detection unit is in the first mode and the tension adjustment unit is increasing the tension of the sheet toward a target value, when the tension detected by the tension detection unit becomes equal to or greater than a first threshold value, the tension detection unit is switched to the second mode; The conveying device described in configuration 1 is characterized in that when the tension detection unit is in the second mode and the tension adjustment means reduces the sheet tension toward a target value, when the tension detected by the tension detection unit becomes equal to or less than a second threshold value that is greater than the first threshold value, the tension detection unit is switched to the first mode. (Configuration 7) the first threshold value is equal to the second lower limit value, 7. The conveying device according to configuration 6, wherein the second threshold value is the same value as the first upper limit value. (Configuration 8) the tension detection unit is configured to be switchable to a third mode capable of detecting tension between a third lower limit value that is greater than the first upper limit value and less than the second upper limit value, and a third upper limit value that is greater than the second upper limit value, The conveying device according to configuration 1, wherein the control unit is capable of switching between the second mode and the third mode based on the tension detected by the tension detection unit. (Configuration 9) The conveying unit has a tension adjusting unit that adjusts the tension applied to the sheet, The control unit is when the tension detection unit is in the first mode and the tension adjustment unit is increasing the tension of the sheet toward a target value, when the tension detected by the tension detection unit becomes equal to or greater than a first threshold value, the tension detection unit is switched to the second mode; when the tension detection unit is in the second mode and the tension adjustment unit is reducing the tension of the sheet toward a target value, when the tension detected by the tension detection unit becomes equal to or smaller than a second threshold value that is larger than the first threshold value, the tension detection unit is switched to the first mode; when the tension detection unit is in the second mode and the tension adjustment unit is increasing the tension of the sheet toward a target value, if the tension detected by the tension detection unit becomes equal to or greater than a third threshold value that is greater than the second threshold value, the tension detection unit is switched to the third mode; The conveying device described in configuration 8, characterized in that when the tension detection unit is in the third mode and the tension adjustment means reduces the sheet tension toward a target value, when the tension detected by the tension detection unit becomes equal to or less than a fourth threshold value that is greater than the third threshold value, the tension detection unit is switched to the second mode. (Configuration 10) the first threshold value is equal to the second lower limit value, The second threshold value is equal to the first upper limit value, the third threshold value is the same value as the third lower limit value, 10. The conveying device according to configuration 9, wherein the fourth threshold value is the same value as the second upper limit value. (Configuration 11) a sheet information acquiring unit that acquires predetermined sheet information of the sheet being conveyed; A conveying device described in any one of configurations 1 to 10, characterized in that the first lower limit value, the first upper limit value, the second lower limit value, and the second upper limit value are individually determined in advance for each of the specified sheet information. (Configuration 12) A conveying device according to any one of configurations 1 to 11, a recording unit that records an image on a sheet; A recording device comprising: [Explanation of symbols]

[0160] 106: tension detection unit, 407: switching control unit (control unit), TL1: first lower limit value, TU1: first upper limit value, TL2: second lower limit value, TU2: second upper limit value

Claims

1. a conveying unit that conveys the sheet while applying tension to the sheet along a conveying direction of the sheet; a tension detection unit that detects tension of the sheet being conveyed to the conveying unit; Equipped with the tension detection unit is configured to be switchable between a first mode capable of detecting tension of a value between a first lower limit value and a first upper limit value, and a second mode capable of detecting tension between a second lower limit value larger than the first lower limit value and a second upper limit value larger than the first upper limit value, A conveying device comprising: a control unit that switches between the first mode and the second mode based on the tension detected by the tension detection unit.

2. The conveying unit has a tension adjusting unit that adjusts the tension applied to the sheet, The conveying device according to claim 1, characterized in that when the tension detection unit is in the first mode and the tension adjustment means is used to increase the sheet tension toward a target value, the control unit switches the tension detection unit to the second mode when the tension detected by the tension detection unit becomes equal to or greater than a threshold value.

3. 3. The conveying apparatus according to claim 2, wherein the threshold value is greater than the second lower limit value and less than the first upper limit value.

4. The conveying unit has a tension adjusting unit that adjusts the tension applied to the sheet, The conveying device according to claim 1, characterized in that when the control unit is in the second mode and the tension adjustment means reduces the sheet tension toward a target value, the control unit switches the tension detection unit to the first mode when the tension detected by the tension detection unit falls below a threshold value.

5. 5. The conveying apparatus according to claim 4, wherein the threshold value is greater than the second lower limit value and less than the first upper limit value.

6. The conveying unit has a tension adjusting unit that adjusts the tension applied to the sheet, The control unit is when the tension detection unit is in the first mode and the tension adjustment unit is increasing the tension of the sheet toward a target value, when the tension detected by the tension detection unit becomes equal to or greater than a first threshold value, the tension detection unit is switched to the second mode; The conveying device according to claim 1, characterized in that when the tension detection unit is in the second mode and the tension adjustment means is used to reduce the sheet tension toward a target value, the tension detection unit is switched to the first mode when the tension detected by the tension detection unit becomes equal to or less than a second threshold value that is greater than the first threshold value.

7. the first threshold value is equal to the second lower limit value, 7. The transport device according to claim 6, wherein the second threshold value is the same value as the first upper limit value.

8. the tension detection unit is configured to be switchable to a third mode capable of detecting tension between a third lower limit value that is greater than the first upper limit value and less than the second upper limit value, and a third upper limit value that is greater than the second upper limit value, 2. The transport device according to claim 1, wherein the control unit is capable of switching between the second mode and the third mode based on the tension detected by the tension detection unit. sending device.

9. The conveying unit has a tension adjusting unit that adjusts the tension applied to the sheet, The control unit is when the tension detection unit is in the first mode and the tension adjustment unit is increasing the tension of the sheet toward a target value, when the tension detected by the tension detection unit becomes equal to or greater than a first threshold value, the tension detection unit is switched to the second mode; when the tension detection unit is in the second mode and the tension adjustment unit is reducing the tension of the sheet toward a target value, when the tension detected by the tension detection unit becomes equal to or smaller than a second threshold value that is larger than the first threshold value, the tension detection unit is switched to the first mode; when the tension detection unit is in the second mode and the tension adjustment unit is increasing the tension of the sheet toward a target value, if the tension detected by the tension detection unit becomes equal to or greater than a third threshold value that is greater than the second threshold value, the tension detection unit is switched to the third mode; The conveying device according to claim 8, characterized in that when the tension detection unit is in the third mode and the tension adjustment means is used to reduce the sheet tension toward a target value, when the tension detected by the tension detection unit becomes equal to or less than a fourth threshold value that is greater than the third threshold value, the tension detection unit is switched to the second mode.

10. the first threshold value is equal to the second lower limit value, the second threshold value is equal to the first upper limit value, the third threshold value is equal to the third lower limit value, 10. The transport device according to claim 9, wherein the fourth threshold value is the same value as the second upper limit value.

11. a sheet information acquiring unit that acquires predetermined sheet information of the sheet being conveyed; 2 . The conveying device according to claim 1 , wherein the first lower limit value, the first upper limit value, the second lower limit value, and the second upper limit value are individually determined in advance for each of the predetermined sheet information.

12. A conveying device according to any one of claims 1 to 11, a recording unit that records an image on a sheet; A recording device comprising:

Images