Inkjet recording device and conveyance control method

Abstract

To convey a recording medium on which an image has been formed along a conveyance path between a conveying mechanism and a heating section without igniting the recording medium.SOLUTION: An inkjet recording device according to one aspect of the present invention comprises: an inkjet recording section 322 that forms an image on a recording medium; a cylindrical temperature-controlled recording drum 321 that conveys the recording medium; a heater that heats an outer circumferential surface of the temperature-controlled recording drum 321; a conveyance path switching section 20 that switches a conveyance path of the recording medium between a first conveyance path that does not pass between the temperature-controlled recording drum 321 and the heater, and a second conveyance path that passes between the temperature-controlled recording drum 321 and the heater; and a control unit 40 that, in accordance with a printing mode, controls a switching operation by the conveyance path switching section 20 and, when the second conveyance path is selected, stops heating by the heater.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an inkjet recording apparatus and a transport control method. [Background technology]

[0002] In recent years, devices (hereinafter simply referred to as "inkjet recording devices") that eject ink from the nozzles of an inkjet head (hereinafter simply referred to as "head") have become widespread. In inkjet recording devices, it is important to ensure that the ink ejected from the nozzles of the head wets and spreads uniformly onto the recording medium. The wetness and spread uniformity of the ink on the recording medium can be ensured by appropriately controlling the temperature of the recording medium.

[0003] For example, when ink is ejected from the nozzles of a head and lands on a recording medium to record an image, the temperature of the recording medium may deviate from the target temperature. In this case, the ink dots may not spread properly, which may result in a decrease in the quality of the recorded image. The target temperature is the optimum temperature depending on the intended use of the image.

[0004] In conventional inkjet recording devices, the temperature (thermal energy) of the transport mechanism that transports the recording medium is transmitted to the recording medium by controlling the temperature of the transport mechanism. The temperature of the transport mechanism is controlled in order to prevent the temperature of the recording medium from deviating from a target temperature.

[0005] For example, Patent Document 1 discloses an inkjet recording apparatus equipped with a drum heater that heats the outer peripheral surface of an image forming drum. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2016 / 190335 Summary of the Invention [Problem to be solved by the invention]

[0007] However, if a recording medium is transported between the transport mechanism and the heating unit while a heating unit such as a drum heater is controlling the heating of the transport mechanism, there is a risk that the recording medium may catch fire or emit smoke. Therefore, while the heating unit is controlling the heating of the transport mechanism, a transport path that does not pass between the transport mechanism and the heating unit is selected.

[0008] However, depending on the printing mode of the recording medium, it may be desirable to transport the recording medium along a transport path that passes between the transport mechanism and the heating unit. Such a printing mode includes, for example, a post-white mode. In the post-white mode, an image is formed on the recording medium using white ink after the image has been formed. In other words, the image is formed on the recording medium in two separate steps.

[0009] In this printing mode, the recording medium must be transported back to the head position while the ink that landed on the surface of the recording medium during the first rotation of the transport mechanism is still in an uncured state. If the ink that landed on the recording medium during the first rotation were cured at that point, the wettability of the recording medium would change. If ink is then ejected onto the recording medium during the second rotation of transport while the wettability of the recording medium has changed, there is a risk that the ink will be repelled by the surface of the recording medium.

[0010] When the recording medium is transported back to the head position while the ink is still uncured, it must be transported without being turned over. This is because if the recording medium is turned over, the uncured ink will adhere to the transport member. Therefore, the recording medium must be transported without passing through a reversing mechanism that turns the recording medium over. One route for transporting the recording medium without passing through the reversing mechanism is one that makes the recording medium make another revolution around the outer periphery of the transport mechanism.

[0011] However, the outer peripheral surface of the conveying mechanism is heated by the aforementioned heating unit. Therefore, when control is performed to make the recording medium make another rotation on the outer peripheral surface of the conveying mechanism, the recording medium is heated by the heating unit. If the recording medium is heated by the heating unit, there is a risk that the recording medium will catch fire. Patent Document 1 does not describe the need to convey the recording medium along a conveying path that passes between the conveying mechanism and the heating unit, nor does it describe a method for achieving such conveyance.

[0012] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to make it possible to transport a recording medium on which an image has been recorded through a transport path that passes between a transport mechanism and a heating unit without causing the recording medium to ignite. [Means for solving the problem]

[0013] An inkjet recording device according to one aspect of the present invention includes an image forming unit that forms an image by ejecting ink onto a recording medium, a cylindrical transport mechanism that holds and transports the recording medium on its outer circumferential surface, a heating unit that heats the outer circumferential surface of the transport mechanism, a switching unit that switches the transport path of the recording medium between a first transport path that does not pass between the transport mechanism and the heating unit and a second transport path that passes between the transport mechanism and the heating unit, and a control unit that controls the switching of the transport path by the switching unit depending on a print mode. When the control unit causes the switching unit to select the first transport path, the control unit stops heating by the heating unit. [Effects of the Invention]

[0014] According to the present invention, a recording medium on which an image has been recorded can be transported along a transport path that passes between the transport mechanism and the heating unit without causing the recording medium to ignite. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a side view showing an example of a schematic configuration of an inkjet recording apparatus according to an embodiment of the present invention. [Figure 2] FIG. 1 is a perspective view showing an example of the configuration of a temperature-controlled recording cylinder according to an embodiment of the present invention; [Figure 3] 1 is a block diagram showing an example of the hardware configuration of an inkjet printing apparatus according to an embodiment of the present invention; [Figure 4] 10A and 10B are diagrams illustrating examples of transport paths switched by a transport path switching unit according to an embodiment of the present invention. [Figure 5] 10 is a flowchart illustrating an example of a procedure for a transport control process when a first printing mode is set according to an embodiment of the present invention. [Figure 6] 10 is a flowchart illustrating an example of a procedure for a transport control process when a second print mode is set according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this specification and the drawings, elements having substantially the same functions or configurations are designated by the same reference numerals, and redundant description will be omitted.

[0017] <General configuration of inkjet recording device> 1 is a side view showing an example of the schematic configuration of an inkjet recording apparatus 1 according to this embodiment. As shown in FIG. 1, the inkjet recording apparatus 1 includes a supply device 200, a recording device 300, and a discharge device 400.

[0018] 1. Feeding device The supply device 200 includes a supply tray 231, a supply unit 220, and a temperature sensor m4. The supply tray 231 is a tray that stores the recording medium P. The supply unit 220 supplies the recording medium P from the supply tray 231 to the recording device 300. The temperature sensor m4 measures the temperature of the recording medium P.

[0019] 1.1 Feeding tray The supply tray 231 is a plate-like member on which a plurality of recording media P cut to a predetermined size are stacked. The supply tray 231 is configured to move up and down depending on the amount of recording media P placed on it. The position of the supply tray 231 is adjusted to a position where the top recording medium P is supplied by the supply unit 220 to the temperature-controlled transport drum 310 of the recording device 300.

[0020] The supply tray 231 is provided with a movable arm (not shown) equipped with a suction unit. The movable arm sucks the top sheet of the supply tray 231 and transports it to the supply unit 220.

[0021] 1.2 Supply section The supply unit 220 includes a circular supply belt 223. The inner side of the circular supply belt 223 is supported by a plurality of rollers, for example, two rollers 221 and 222. When the rollers 221 and 222 rotate with the recording medium P placed on the supply belt 223, the recording medium P is supplied to the recording device 300 along the supply belt 223.

[0022] 1.3 Temperature Sensor The temperature sensor m4 is configured, for example, by a non-contact infrared detection sensor. The temperature sensor m4 is installed at a position facing the top recording medium P on the supply tray 231, and measures the temperature of the recording medium P. The temperature sensor m4 then outputs the measured temperature of the top recording medium P to the control unit 40 in the recording device 300.

[0023] 1.4 Recording Media The recording medium P placed on the supply tray 231 is made up of, for example, sheets of paper. Examples of sheets of paper include plain paper ranging from thin paper to thick paper, high-quality paper, coated printing paper such as art paper or coated paper, water-soluble paper, Japanese paper, and postcard paper. The material of the recording medium P is not limited to paper. The recording medium P may also be made of, for example, plastic film, cloth, leather, etc. The color of the recording medium P is also not limited to white.

[0024] 2. Recording device As shown in FIG. 1, a recording apparatus 300 according to this embodiment includes a temperature-controlled transport drum 310, a recording mechanism 320, a temperature-controlled recording drum 321, an image reading unit 324, and a reversing mechanism 330.

[0025] The temperature-controlled transport drum 310 carries the recording medium P along its outer circumferential surface and transports it to the recording mechanism 320. The temperature-controlled transport drum 310 is supplied with the recording medium P supplied from the supply unit 220 of the supply device 200, or the recording medium P delivered from the second reversing drum 332 of the reversing mechanism 330. A heater H1 that heats the outer circumferential surface of the temperature-controlled heating drum 310 is provided near the temperature-controlled transport drum 310. The heat of the temperature-controlled transport drum 310 is then transmitted to the recording medium P as it is transported along the outer circumferential surface of the temperature-controlled heating drum 310 heated by the heater H1. The temperature of the heating temperature by the heater H1 is adjusted by the control unit 40, and the temperature of the recording medium P transported along the temperature-controlled transport drum 310 is also adjusted.

[0026] Recording mechanism 320 (an example of an image forming unit) is composed of temperature-controlled recording cylinder 321 and inkjet recording unit 322. Temperature-controlled recording cylinder 321 transports recording medium P handed over from temperature-controlled transport cylinder 310 while adjusting the temperature. Inkjet recording unit 322 forms (records) an image on recording medium P transported on temperature-controlled recording cylinder 321. Inkjet recording unit 322 has heads 322W, 322Y, 322M, 322C, and 322K (each an example of an image forming unit).

[0027] Head 322W is an ink head that ejects white ink onto the recording medium P, and head 322Y is an ink head that ejects yellow ink onto the recording medium P. Head 322M is an ink head that ejects magenta ink onto the recording medium P, and head 322C is an ink head that ejects cyan ink onto the recording medium P. Head 322K is an ink head that ejects black ink onto the recording medium P. Heads 322W, 322Y, 322M, 322C, and 322K are arranged in this order from the upstream side in the transport direction of the recording medium P, at predetermined intervals.

[0028] The recording mechanism 320 according to this embodiment can perform printing according to a plurality of printing modes. The plurality of printing modes include a background printing mode, a white-on-white mode, and an image reading mode. In the background printing mode, a background is first formed on a transparent plastic film by solidly applying white ink or the like, and then an image is formed on the recording medium P after the background has been formed. Note that the color of the image printed as the background in the background printing mode is not limited to white, and may be another color.

[0029] The after-white mode is a mode in which an image is formed in white ink, such as highlights and white text, on the recording medium P on which an image has already been formed. The background printing mode and after-white mode are examples of a first printing mode in which an image is formed on the same side of the recording medium P during the first and second rotations of transport by the transport mechanism (temperature-controlled recording cylinder 321).

[0030] In the first printing mode, once image formation on the recording medium P is completed on both the first and second rotations of transport by the temperature-controlled recording cylinder 321, fixing is performed by the ink curing and drying device 323. This is because if a fixing process is performed on the recording medium P on which an image has been formed on the first rotation of transport, the wettability and other properties of the recording medium P will change. If the wettability of the recording medium P changes, there is a possibility that the recording medium P will repel the ink ejected from the inkjet recording unit 322 on the second rotation.

[0031] Therefore, the recording medium P needs to be transported again to the position of the inkjet recording unit 322 while the ink that landed on the recording medium P during the first round of transport is still in an uncured state. If the recording medium P is transported using the reversing mechanism 330 (described later) at this time, the recording medium P will be turned over. When the recording medium P is turned over, the uncured ink on the recording medium P will adhere to the outer periphery of the reversing mechanism 330.

[0032] Therefore, in the first printing mode in this embodiment, the recording medium P after image formation is controlled to make another rotation along the temperature-controlled recording cylinder 321 without being handed over to the reversing mechanism 330. This control is performed by the control unit 40 instructing the transport path switching unit 20, which will be described later, to switch the transport destination of the recording medium P.

[0033] The image reading mode is an example of a second printing mode in which the image reading unit 324 reads an image after the image is formed by the recording mechanism 320. In the image reading mode, the recording mechanism 320 forms an image on the recording medium P during the first rotation of the temperature-controlled recording cylinder 321. Then, during the second rotation, the image reading unit 324 reads the recording medium P on which the image has been formed. In other words, even in the image reading mode, the control unit 40 controls the recording medium P after the image formation to make another rotation along the temperature-controlled recording cylinder 321.

[0034] Furthermore, in this embodiment, in the second print mode, the control unit 40 also controls the conveying speed to be different between the first and second revolutions of the temperature-controlled recording cylinder 321 conveying the recording medium P. More specifically, the control unit 40 changes the conveying speed during the second revolution to be slower than the conveying speed during the first revolution. By performing such control by the control unit 40, it becomes possible to increase the resolution of the reading of the recording medium P by the image reading unit 324 during the second revolution of the conveying.

[0035] The control of changing the conveying speed to a slower speed during the second rotation is performed, for example, when performing image inspections to detect ejection defects, misalignment of ink landing positions, ink density, etc. This is because these image inspections require the generation of high-resolution scanned images.

[0036] The recording mechanism 320 is also provided with a transport path switching unit 20. The transport path switching unit 20 switches the transport destination of the recording medium P on which an image has been recorded to one of the temperature-controlled recording cylinder 321, the discharge mechanism 410, and the reversing mechanism 330. When the transport path switching unit 20 sets the transport destination of the recording medium P to the temperature-controlled recording cylinder 321, the recording medium P makes another rotation around the temperature-controlled recording cylinder 321.

[0037] Reversing mechanism 330 includes first reversing cylinder 331 and second reversing cylinder 332. First reversing cylinder 331 reverses recording medium P delivered from recording mechanism 320, and delivers the recording medium P after being reversed to second reversing cylinder 332. Second reversing cylinder 332 delivers recording medium P delivered from first reversing cylinder 331 to temperature-controlled transport cylinder 310 via a transport path that does not pass between heater H2 and temperature-controlled recording cylinder 321.

[0038] 2.1 Transfer mechanism 2.1.1 Temperature-controlled conveying drum The transport mechanism according to this embodiment includes a temperature-controlled transport cylinder 310. The temperature-controlled transport cylinder 310 transports the recording medium P supplied from the supply unit 220 of the supply device 200 or the recording medium P transported from the second reversing cylinder 332 to the temperature-controlled recording cylinder 321. The temperature-controlled transport cylinder 310 also has the function of transporting the recording medium P while adjusting its temperature, as described above.

[0039] In this embodiment, the circumferential length of the temperature-controlled transport drum 310 is set to, for example, approximately twice or more the maximum length in the transport direction of the recording medium P, which is a paper sheet. By setting the circumferential length of the temperature-controlled transport drum 310 to such a length, the length over which the recording medium P contacts the temperature-controlled transport drum 310 can be increased. This makes it possible to stably adjust the temperature of the recording medium P.

[0040] A heater H1, which is a temperature adjusting member for the temperature controlled transfer drum 310, is installed near the temperature controlled transfer drum 310. The heater H1 is configured, for example, by a non-contact heater such as a halogen lamp that emits infrared rays.

[0041] In one specific example, the temperature-controlled transfer drum 310 is configured with a known Peltier device or the like that operates under the control of the control unit 40. The Peltier device is a Peltier roller with a sheet-like thermoelectric conversion device element built in. The thermoelectric conversion device element switches between cooling and heating operations by switching the polarity of the voltage applied to the sheet-like element between + and -.

[0042] Heater H1 is operated under the control of control unit 40 and radiates heat to preheat temperature-controlled transport drum 310. This heats temperature-controlled transport drum 310 and recording medium P transported around the temperature-controlled transport drum 310 to a predetermined temperature prior to the image recording process. The image recording process includes an image recording process on the front side of recording medium P and an image recording process on the back side.

[0043] As the temperature adjusting member, a heating or cooling fan, a roller or belt incorporating a thermoelectric conversion device, or the like can also be used.

[0044] A temperature sensor m1 is installed near the heater H1. The temperature sensor m1 detects the temperature of the temperature-controlled transfer drum 310 and outputs information about the detected temperature to the control unit 40. A non-contact element such as a thermopile can be used as the temperature detection element of the temperature sensor m1. However, a contact element such as a thermocouple or a thermistor may also be used as the temperature detection element of the temperature sensor m1.

[0045] The control unit 40 controls the heating or cooling operation of the heater H1 based on the temperature detected by the temperature sensor m1 so that the outer circumferential surface of the temperature-controlled transfer drum 310 reaches a predetermined temperature.

[0046] 2.1.2 Delivery of recording media The temperature-controlled transport drum 310 is equipped with a claw portion 310a for receiving and delivering the recording medium P. The claw portion 310a can be opened and closed, and when closed, holds the front end of the recording medium P in the transport direction. A cam mechanism (not shown) is provided in the claw portion 310a. The cam mechanism opens and closes each of the multiple claws that make up the claw portion 310a. The cam mechanism closes the claw portion 310a when receiving the recording medium P, and opens the claw portion 310a when delivering the recording medium P. The operation of the cam mechanism is controlled by the control unit 40 based on information about the transport destination of the recording medium P switched by the transport path switching unit 20.

[0047] The temperature controlled transfer drum 310 has three positions for transferring the recording medium P: position A, position B, and position C. Position A: A location where the recording medium P is transferred from the supply section 220 of the supply device 200 to the temperature-controlled transport drum 310. Position B: A position where the recording medium P is transferred from the second reversing cylinder 332 of the reversing mechanism 330 to the temperature-controlled transport cylinder 310. Position C: A position where the recording medium is transferred from the temperature-controlled transport cylinder 310 to the temperature-controlled recording cylinder 321.

[0048] From the viewpoint of shortening the transport path and preventing the device from becoming bulky, it is preferable that positions B and C are located downstream of position A in the transport direction, and position B is located between positions A and C.

[0049] The second reversing cylinder 332 is provided with one claw portion 332a, and the temperature-controlled transport cylinder 310 is provided with two claw portions 310a spaced at 180° intervals. The temperature-controlled recording cylinder 321 is provided with three claw portions 321a spaced at 120° intervals. When the temperature-controlled recording cylinder 321 rotates 120° in the counterclockwise direction F2 in FIG. 1, the first reversing cylinder 331 rotates in the clockwise direction F1. When the first reversing cylinder 331 rotates in the clockwise direction F1, the second reversing cylinder 332 rotates once in the counterclockwise direction F2. When the second reversing cylinder 332 rotates once in the counterclockwise direction F2, the temperature-controlled transport cylinder 310 rotates 180° in the clockwise direction F1.

[0050] 1, position A is formed on the opposite side of position C across temperature-controlled transport drum 310. By forming position A in such a position, it is possible to increase the amount of wrapping of recording medium P supplied from supply device 200 around temperature-controlled transport drum 310. In other words, it is possible to ensure sufficient contact time with recording medium P, thereby enabling stable temperature control of recording medium P.

[0051] 2.2 Recording mechanism The recording mechanism 320 includes a temperature-controlled recording cylinder 321 and an inkjet recording unit 322 . 2.2.1 Temperature-controlled recording cylinder The temperature-controlled recording cylinder 321 receives the recording medium P transported from the temperature-controlled transport cylinder 310, and transports the recording medium P while controlling its temperature while supporting it on its outer circumferential surface. The temperature-controlled recording cylinder 321 delivers the transported recording medium P after controlling its temperature to the discharge mechanism 410 or the reversing mechanism 330.

[0052] Here, the configuration of the temperature-controlled recording cylinder 321 will be described with reference to Fig. 2. Fig. 2 is a perspective view showing an example of the configuration of the temperature-controlled recording cylinder 321. As shown in Fig. 2, the temperature-controlled recording cylinder 321 is provided with claw portions 321a for supporting the recording medium P on its outer circumferential surface, and an air intake portion 321s.

[0053] Claw portion 321a is composed of multiple claws. The multiple claws are arranged at predetermined intervals from one another along the rotation axis direction of temperature-controlled recording cylinder 321 (the sub-scanning direction of inkjet recording unit 322). Claw portion 321a also includes a cam mechanism (not shown). The cam mechanism operates to open and close the claws at positions facing temperature-controlled transport cylinder 310, cylinder 411 included in discharge mechanism 410 (described below), and first reversing cylinder 331.

[0054] Specifically, for example, claw portion 321a closes at the timing when one end of the recording medium P is handed over from temperature-controlled transport drum 310, thereby holding the one end of the recording medium P. Claw portion 321a also opens at the timing when one end of the recording medium P is handed over to drum 411 or first reversing drum 331, which are provided in the discharge mechanism. As a result, one end of the recording medium P is handed over to claw portion 411a of drum 411 or claw portion 331a of first reversing drum 331.

[0055] The temperature-controlled recording cylinder 321 has three holding areas for recording media P, which are obtained by dividing its outer circumferential surface into thirds. In other words, the temperature-controlled recording cylinder 321 can hold a maximum of three recording media P. Note that the number of holding areas for recording media P on the temperature-controlled recording cylinder 321 is not limited to three.

[0056] The intake section 321s includes a plurality of intake holes provided on the outer peripheral surface of the temperature-controlled recording cylinder 321 and a suction force generating section (not shown). The suction force generating section generates a suction force that draws gas into the temperature-controlled recording cylinder 321 through the intake holes. Examples of members used in the suction force generating section include a blower and a fan. The suction force generated by the suction force generating section sucks the recording medium P being transported along the outer peripheral surface of the temperature-controlled recording cylinder 321 so that it follows the outer peripheral surface of the temperature-controlled recording cylinder 321.

[0057] The hollow interior of the temperature-controlled recording cylinder 321 is divided into three sections corresponding to the holding areas of the three recording media P. The temperature-controlled recording cylinder 321 also has an intake circuit (not shown). The intake circuit is a circuit that can individually select and apply suction force to each of the intake sections 321s of the three holding areas of the temperature-controlled recording cylinder 321. By configuring the temperature-controlled recording cylinder 321 in this way, it can be operated so that suction force is not applied to the holding areas that are not holding a recording medium P.

[0058] 2, a portion of the recording medium P is shown curled up from the outer peripheral surface of the temperature-controlled recording cylinder 321, but this is for the purpose of illustrating the air intake holes. In reality, when an image is recorded by the inkjet recording unit 322, the entire recording medium P is supported so as to fit along the outer peripheral surface of the temperature-controlled recording cylinder 321.

[0059] Returning to Figure 1, the explanation will continue. The temperature-controlled recording cylinder 321 is provided with a cylinder rotation motor (not shown). The cylinder rotation motor is driven under the control of the control unit 40. The temperature-controlled recording cylinder 321 is rotated in the counterclockwise direction F2 by an angle proportional to the amount of rotation of the cylinder rotation motor, whereby the recording medium P is transported by the temperature-controlled recording cylinder 321.

[0060] A heater H2 is disposed at a position facing a portion along the outer peripheral surface from position E to position C in the rotation (transport) direction (counterclockwise direction F2) of the temperature-controlled recording cylinder 321. Position E is the location where the recording medium P is transferred from the temperature-controlled recording cylinder 321 to the first reversing cylinder 331.

[0061] The heater H2 (an example of a heating unit) is operated under the control of the control unit 40, and heats the temperature-controlled recording cylinder 321 to a predetermined temperature by radiating heat for preheating the temperature-controlled recording cylinder 321.

[0062] When the temperature-controlled recording cylinder 321 controls the recording medium P after image formation to make another revolution, the recording medium P is transported between the heater H2 and the temperature-controlled recording cylinder 321. If the recording medium P continues to be heated by the heater H2, there is a risk of the recording medium P catching fire. Therefore, in this embodiment, when the temperature-controlled recording cylinder 321 controls the recording medium P after image formation to make another revolution, the control unit 40 controls the heater H2 to turn off heating.

[0063] A temperature sensor m2 is installed near the heater H2. The temperature sensor m2 detects the temperature of the temperature-controlled transfer drum 310 and outputs information about the detected temperature to the control unit 40. The temperature detection element of the temperature sensor m2 may be the same as that of the temperature sensor m1 described above.

[0064] A recording medium detection unit 50 is provided near the temperature sensor m2 and upstream in the conveying direction of the recording medium P. The recording medium detection unit 50 is configured with, for example, a reflective sensor, and detects the recording medium P being conveyed by the temperature-controlled recording cylinder 321. The recording medium detection unit 50 then outputs the detection result to the control unit 40.

[0065] When the above-described control to make the recording medium P rotate again by the temperature-controlled recording cylinder 321 after image formation is not performed, the recording medium P is transported along a transport path that does not pass between the heater H2 and the temperature-controlled recording cylinder 321. In other words, the recording medium P is transported along a transport path that passes through the first reversing cylinder 331, the second reversing cylinder 332, and the temperature-controlled transport cylinder 310 and returns to the temperature-controlled recording cylinder 321. Therefore, when the transport path switching unit 20 selects a transport path that does not pass between the heater H2 and the temperature-controlled recording cylinder 321, the recording medium P will not pass between the heater H2 and the temperature-controlled recording cylinder 321. If the recording medium P does pass between the heater H2 and the temperature-controlled recording cylinder 321, it is because the recording medium P has erroneously entered. The recording medium detection unit 50 is a sensor that detects erroneous entry of the recording medium P.

[0066] When the recording medium detection unit 50 detects the erroneous entry of a recording medium P, the control unit 40 controls the discharge mechanism 410 to discharge the recording medium P. By performing such control by the control unit 40, the erroneous entry of the recording medium P can be prevented from being heated by the heater H2.

[0067] When control is performed to make the recording medium P after image formation make another revolution by the temperature-controlled recording cylinder 321, the control unit 40 turns off detection of the recording medium P by the recording medium detection unit 50. By performing such control by the control unit 40, detection of the recording medium P by the recording medium detection unit 50 is no longer performed. In other words, the recording medium P is prevented from being discharged to the discharge tray 431 by the discharge mechanism 410. Therefore, it is possible to make the recording medium P after image formation make another revolution by the temperature-controlled recording cylinder 321. As described above, when control is performed to make the recording medium P after image formation make another revolution by the temperature-controlled recording cylinder 321, heating by the heater H2 is also turned off. Therefore, the recording medium P is not heated by the heater H2.

[0068] 2.2.2 Delivery of recording media The temperature-controlled recording cylinder 321 has three claws 321a for transferring the recording medium P. The structure of the claws 321a is the same as that of the claws 310a, so a description thereof will be omitted. In the temperature-controlled recording cylinder 321, the three claws 321a are provided at 120° intervals around the rotation axis of the temperature-controlled recording cylinder 321. The transfer positions for the recording medium P on the temperature-controlled recording cylinder 321 are the following three positions: Position C, Position D, and Position F.

[0069] Position C (already explained in the transfer position of the recording medium P related to the temperature-controlled transfer drum 310) Position D: A position where the recording medium P is transferred from the temperature-controlled recording cylinder 321 to the cylinder 411 of the discharge mechanism 410. Position E: A position where the recording medium P is transferred from the temperature-controlled recording cylinder 321 to the first reversing cylinder 331 of the reversing mechanism 330.

[0070] For example, when double-sided printing is performed, the recording medium P is transported from the temperature-controlled recording cylinder 321 through the reversing mechanism 330 and the temperature-controlled transport cylinder 310, and then back to the temperature-controlled recording cylinder 321. In this case, the claws 321a provided on the cylinder on the upstream side in the transport direction are controlled to open, and the claws 321a provided on the cylinder on the downstream side in the transport direction are controlled to close. By controlling the opening and closing of the claws 321a in this manner, one end of the recording medium P is sequentially transferred from the cylinder on the upstream side in the transport direction to the cylinder on the downstream side in the transport direction.

[0071] 2.2.3 Inkjet recording unit Inkjet recording unit 322 applies ink to one side of recording medium P to record an image. Inkjet recording unit 322 is equipped with heads 322W, 322Y, 322M, 322C, and 322K. Inkjet recording unit 322 also is equipped with a head driving unit 30 (see FIG. 3) that drives each of these heads.

[0072] Each of the heads 322W, 322Y, 322M, 322C, and 322K has a nozzle opening (not shown) that ejects ink onto the recording medium P. The nozzle opening is provided on an ink ejection surface that faces the transport surface of the temperature-controlled recording cylinder 321. The ink is applied to the recording medium P by ejecting ink from the nozzle opening onto the recording medium P at appropriate timing according to the rotation of the temperature-controlled recording cylinder 321 that holds the recording medium P. Then, an image is recorded on the recording medium P by applying the ink to the recording medium P.

[0073] Inkjet head The distance between the ink ejection surface of each of the heads 322W, 322Y, 322M, 322C, and 322K and the transport surface of the temperature controlled recording cylinder 321 is set to a predetermined constant distance. In addition, each of the heads 322W, 322Y, 322M, 322C, and 322K has a plurality of nozzles that individually eject ink, arranged in a direction perpendicular to the transport direction of the recording medium P.

[0074] The inkjet recording unit 322 is provided with an ink tank (not shown) that stores ink and supplies ink to each head. Each inkjet recording unit 322 may be provided with an ink heater or the like as a means for heating the ink before ejection.

[0075] A supply pressure adjustment mechanism (not shown) is provided in the ink path leading from the ink tank to each of the heads 322W, 322Y, 322M, 322C, and 322K. The supply pressure from the supply pressure adjustment mechanism is adjusted to a pressure slightly lower than atmospheric pressure. Adjusting the supply pressure to this pressure prevents ink from spilling out of the nozzles of each of the heads 322W, 322Y, 322M, 322C, and 322K.

[0076] The head driver 30 supplies drive signals under the control of the controller 40. The drive signals are signals that deform the piezoelectric elements of each head at appropriate timing in accordance with image data. When each head 322W, 322Y, 322M, 322C, and 322K is driven based on the drive signals, an amount of ink corresponding to the pixel value of the image data is ejected from each nozzle.

[0077] ink For example, actinic ray curable ink can be used. The curing characteristics of actinic ray curable ink are often susceptible to temperature. Therefore, by optimizing the temperature of the temperature-controlled recording cylinder 321 when using ink, better and more stable image recording can be achieved.

[0078] For example, actinic ray curable ink may be one that is cured by irradiation with ultraviolet rays. The energy rays that cure the ink are not limited to ultraviolet rays. The energy rays may be other energy rays such as infrared rays or electron beams. The light source of the ink curing and drying device 323, which will be described later, is replaced depending on the type of energy rays.

[0079] The actinic radiation-curable ink may also contain other components as necessary. Examples of such other components include gelling agents, polymerization initiators, polymerization inhibitors, coloring materials such as dyes and pigments, dispersants, fixing resins, surfactants, pH adjusters, moisturizers, and ultraviolet absorbers. The composition may contain only one type of such other component, or two or more types.

[0080] Furthermore, from the viewpoint of recording images with good quality and stability, the ink is preferably a phase-change ink, and the phase change in the ink preferably occurs before and after recording on the recording medium P.

[0081] When the ink contains a solid component containing a colorant and a solvent component, the ink curing and drying device 323 may be configured as a drying device that evaporates the solvent component. Examples of the drying device include non-contact drying devices such as an infrared heater and a hot air blower.

[0082] 2.2.4 Ink curing and drying device When ultraviolet curable ink is used, an LED, a high-pressure mercury lamp, or the like is used for the light emitting unit (not shown) of the ink curing and drying device 323 (an example of a fixing unit). The ink curing and drying device 323 emits active rays such as ultraviolet light from the light emitting unit toward the recording medium P carried on the temperature controlled recording cylinder 321. This causes a polymerization reaction in the ink on the recording medium P, causing the ink on the recording medium P to harden and be fixed onto the recording medium P.

[0083] The light source of the light-emitting unit is not limited to an LED or a high-pressure mercury lamp. For example, a mercury lamp having an operating pressure of several hundred Pa to 1 Mega Pa, a light source that can be used as a germicidal lamp, or the like may be used as the light source. Alternatively, a cold cathode fluorescent lamp, an ultraviolet laser light source, a metal halide lamp, or the like may be used as the light source. It is desirable that the light source of the light-emitting unit be a power-saving light source that can irradiate ultraviolet light at a higher illuminance.

[0084] The ink curing and drying device 323 is provided near the outer peripheral surface of the temperature controlled recording cylinder 321. More specifically, the ink curing and drying device 323 is provided downstream of the inkjet recording unit 322 in the transport direction of the recording medium P and upstream of the transport path switching unit 20. By arranging the ink curing and drying device 323 in such a position, the ink on the recording medium P is cured and dried before the recording medium P reaches the position of the transport path switching unit 20.

[0085] Temperature sensor near downstream of inkjet recording section A temperature sensor m3 is installed near the downstream side of the inkjet recording unit 322 and upstream of the ink curing and drying device 323. The temperature sensor m3 detects the temperature of the recording medium P and outputs the temperature to the control unit 40. The temperature sensor m3 can also detect the surface temperature of the temperature-controlled recording cylinder 321 when the recording medium P is not passing through.

[0086] 2.3 Image reading unit The image reading unit 324 is provided downstream of the ink curing and drying device 323. The image reading unit 324 is configured with, for example, an in-line sensor, and optically reads the entire surface of the recording medium P being transported along the outer circumferential surface of the temperature-controlled recording cylinder 321. The image reading unit 324 then outputs the read image to the control unit 40.

[0087] As described above, in the image reading mode where high-resolution image reading is required, the control unit 40 controls the temperature-controlled recording cylinder 321 to slow down the conveying speed during the second rotation of the conveyance. Specifically, the control unit 40 sets the conveying speed of the temperature-controlled recording cylinder 321 during image formation during the first rotation of the conveyance to 3000 sph (sheets per hour) or 6000 sph. Then, during image reading during the second rotation, the control unit 40 controls the conveying speed of the temperature-controlled recording cylinder 321 to slow down to 750 sph or the like. This control by the control unit 40 can improve the reading resolution in the sub-scanning (conveyance) direction of the recording medium P on which an image has been formed.

[0088] 2.4 Reversing mechanism The reversing mechanism 330 is a mechanism that turns over the recording medium P, one side of which has been coated with ink, and delivers the turned-over recording medium P to the temperature-controlled transport drum 310.

[0089] The reversing mechanism 330 is composed of a first reversing cylinder 331 and a second reversing cylinder 332. The first reversing cylinder 331 receives the recording medium P from the temperature-controlled recording cylinder 321 at the position E. The first reversing cylinder 331 then transfers the received recording medium P to the second reversing cylinder 332 at the position F. The second reversing cylinder 332 transfers the received recording medium P to the temperature-controlled transport cylinder 310 at the position B. The temperature-controlled transport cylinder 310 transfers the recording medium P received at the position B to the temperature-controlled recording cylinder 321 at the position C. By operating the reversing mechanism 330 in this manner, the recording medium P transferred from the temperature-controlled recording cylinder 321 is reversed, and the reversed recording medium P is transferred to the temperature-controlled recording cylinder 321 again.

[0090] The diameter of first reversing drum 331 is, for example, approximately twice the diameter of second reversing drum 332. The rotational movements of first reversing drum 331 and second reversing drum 332 are controlled by motors (hereinafter referred to as "independent drive motors"; not shown) that are independent drive sources.

[0091] 2.4.1 Delivery of recording media The first reversing drum 331 has two claws 331a. Each claw 331a can be opened and closed, and when closed, it holds the leading end of the recording medium P in the transport direction. The rotation of the first reversing drum 331 and the second reversing drum 332 is controlled by an independent drive motor. Specifically, the independent drive motor controls the timing at which the end not gripped by the claws 331a reaches position F. More specifically, the independent drive motor controls the rotation of the first reversing drum 331 and the second reversing drum 332 so that the end of the ungripped recording medium P reaches position F at the timing at which the claws 331a of the first reversing drum 331 and the claws 332a of the second reversing drum 332 reach position F. The independent drive motor controls the closing of the claws 322a of the second reversing drum 332 at the timing at which the claws 332a of the second reversing drum 332 pass position F. This control is performed by the independent drive motor, and the second reversing cylinder 332 receives the end of the recording medium P. Thereafter, the claws of the claw portion 331a of the first reversing cylinder 331 release the recording medium P at a predetermined position, and the recording medium P is transferred from the first reversing cylinder 331 to the second reversing cylinder 332.

[0092] Furthermore, when the claws 332a of the second reversing cylinder rotate to position B, which is a position closely facing the temperature-controlled transport cylinder 310, while gripping the end of the recording medium P, the claws 332a of the second reversing cylinder are controlled to open. At the same time, the claws 310a of the temperature-controlled transport cylinder 310, which has reached position B, are controlled to close.

[0093] By transporting the recording medium P in this manner by the reversing mechanism 330, the recording medium P, which has been turned over, is returned to the temperature-controlled recording cylinder 321 without passing between the heater H2 and the temperature-controlled recording cylinder 321. Therefore, it is possible to prevent the recording medium P, which has been turned over, from catching fire or emitting smoke.

[0094] 3. Discharge device The discharge device 400 according to the present invention includes a discharge mechanism 410. The discharge mechanism 410 transports the recording medium P transported from the transport path switching unit 20 to a discharge tray 431.

[0095] 3.1 Ejection mechanism 1, the discharge mechanism 410 according to this embodiment includes cylinders 411 to 413, a discharge chain 415, multiple gears 414, and multiple tension gears 416. The cylinder 411 receives the recording medium P from the temperature-controlled recording cylinder 321. The cylinder 412 receives the recording medium P from the cylinder 411. The multiple discharge chains 415 receive the recording medium P from the cylinder 412 and deliver it to the discharge section 420. The multiple gears 413 drive the discharge chain 415. The multiple tension gears 416 apply tension to each of the multiple gears 414 and the discharge chain 415.

[0096] The discharge mechanism cylinder 411 has two claws 411a that clamp one end of the recording medium P. The structure of the claws 411a is the same as the claws 321a of the temperature controlled recording cylinder 321, so a description thereof will be omitted.

[0097] When the claw portion 321a of the temperature-controlled recording cylinder 321 and the claw portion 411a of the cylinder 411 are at the transfer position D from the temperature-controlled recording cylinder 321 to the discharge mechanism 410, the multiple claws that make up the claw portion 321a of the temperature-controlled recording cylinder 321 are open. Also, the multiple claws that make up the claw portion 411a of the cylinder 411 are closed. The opening and closing of the claw portion 411a is performed by a cam mechanism (not shown) based on the control of the control unit 40. By performing such opening and closing operations of the claw portions by the cam mechanism, the recording medium P is transferred from the temperature-controlled recording cylinder 321 to the cylinder 411 of the discharge mechanism 410.

[0098] 3.1.1 Discharge section The trunk 412 is also provided with two sets of claws 412a. In addition, the discharge chain 415 is also provided with a plurality of claws (not shown) at intervals of 1 / 2 the circumferential length of the trunk 411 and the trunk 412. Furthermore, the trunk 412 is provided with a cam mechanism (not shown). The cam mechanism opens and closes the plurality of claws of each claw portion of the trunk 411 and the trunk 412 at a position where the trunk 411 and the trunk 412 face each other. In addition, the cam mechanism opens and closes the plurality of claws of each claw portion of the trunk 411 and the discharge chain 415 at a position where the trunk 411 and the discharge chain 415 face each other.

[0099] The recording medium P is transferred from the body 411 to the body 412 and then to the discharge chain 415. Then, at the position of the discharge section 420, the recording medium P is placed on the discharge tray 431 by opening the multiple claws of the claw section of the discharge chain 415.

[0100] The discharge unit 420 stores the recording medium P after image recording on a discharge tray 431 until the recording medium P is removed by the user.

[0101] 4.Transport path switching section The transport path switching unit 20 (see FIG. 3, an example of a switching unit) switches the destination of the recording medium P on which an image is formed by the inkjet recording unit 322 to either the discharge mechanism 410, the reversing mechanism 330, or the temperature-controlled recording cylinder 321.

[0102] When single-sided printing is performed by the inkjet recording unit 322, the transport path switching unit 20 sets the transport destination of the recording medium P on which an image has been formed to the discharge mechanism 410. On the other hand, when double-sided printing is performed by the inkjet recording unit 322, the transport destination of the recording medium P on which an image has been formed is set to the first reversing cylinder 331 of the reversing mechanism 330. Furthermore, the transport path switching unit 20 sets the transport destination of the recording medium P on which images have been formed on both the front and back sides to the cylinder 411 of the discharge mechanism 410.

[0103] Furthermore, in the after-white mode or background printing mode, the transport path switching unit 20 changes the transport destination of the recording medium P between the first and second revolutions around the temperature-controlled recording cylinder 321. More specifically, at the end of the first revolution, the transport path switching unit 20 does not switch the transport destination of the recording medium P on which an image has been formed but the ink is not yet cured. In other words, the transport destination of the recording medium P on which an image has been formed is set to the temperature-controlled recording cylinder 321. As a result, the recording medium P makes another revolution around the temperature-controlled recording cylinder 321. Meanwhile, in the second revolution, the transport path switching unit 20 switches the transport destination of the recording medium P to the discharge mechanism 410. By performing such control, the recording medium P on which an image has been formed in each of the first and second revolutions is discharged to the discharge tray 431.

[0104] Also, in the image reading mode, the transport path switching unit 20 does not switch the transport destination of the recording medium P on which the image has been read at the end of the first rotation. That is, the temperature-controlled recording cylinder 321 makes another rotation. On the other hand, at the end of the second rotation, the transport path switching unit 20 sets the transport destination of the recording medium P on which the image has been read in the second rotation to the discharge mechanism 410.

[0105] 5. Control Unit The control unit 40 adjusts the set temperatures of the temperature control members and the like in accordance with the desired image recording conditions based on the temperature information output from each temperature sensor. The temperature control members are a collective term for the temperature control transport drum 310, the temperature control recording drum 321, heaters H1 and H2, and other temperature control members (not shown). The control unit 40 also controls the operations of the temperature control transport drum 310, the recording mechanism 320, the discharge mechanism 410, and the reversing mechanism 330.

[0106] The "image recording conditions" include the amount of ink on the front surface, paper size, size of the image on the front surface, type of ink, material of the recording medium P, basis weight of the recording medium P, temperature and humidity of the recording device 300, etc. The amount of ink on the front surface is the amount of ink that constitutes the ink image recorded on the front surface of the recording medium P. The size of the image on the front surface is the size of the image formed on the front surface of the paper.

[0107] The control unit 40 also instructs the transport path switching unit 20 to set the transport destination of the recording medium P. For example, if single-sided printing is specified in the print job, the control unit 40 causes the transport path switching unit 20 to switch the transport destination of the recording medium P after image formation to the cylinder 411 of the discharge mechanism 410. If double-sided printing is specified in the print job, the control unit 40 causes the transport path switching unit 20 to switch the transport destination of the recording medium P, on whose first side an image has been formed, to the first reversing cylinder 331 of the reversing mechanism 330. If the printing mode is the first mode, the control unit 40 causes the transport path switching unit 20 to set the transport destination of the recording medium P, on whose first side an image has been formed, to the temperature-controlled recording cylinder 321. If the printing mode is the first mode, the control unit 40 also controls to turn off heating by the heater H2 and detection of the recording medium P by the recording medium detection unit 50.

[0108] Furthermore, when the printing mode is the second mode (image reading mode) and high-resolution reading is required, the control unit 40 controls to reduce the transport speed of the recording medium P in the second rotation. Note that the control unit 40 may also control to reduce the transport speed of the recording medium P in the second rotation when another printing mode, such as the after-white mode, is set. In the after-white mode, the control to reduce the transport speed in the second rotation by the temperature-controlled recording cylinder 321 is performed, allowing the inkjet recording unit 322 to draw highlights, white characters, and the like of the image with high resolution.

[0109] <Configuration of the control system of the inkjet printing apparatus> Next, the configuration of the control system of the inkjet recording apparatus 1 of the present invention will be described with reference to Fig. 3. Fig. 3 is a block diagram showing an example of the hardware configuration of the inkjet recording apparatus 1.

[0110] The inkjet recording apparatus 1 includes a data input unit 10, an inkjet recording unit 322, an ink curing and drying device 323, an image reading unit 324, a temperature detection unit 80, and a recording medium detection unit 50. The inkjet recording apparatus 1 also includes a supply unit 220, a temperature-controlled transport drum 310, a recording mechanism 320, a transport path switching unit 20, a reversing mechanism 330, and a discharge mechanism 410.

[0111] The data input unit 10 includes an input interface and memory connected to an external device (not shown). The external device (not shown) is, for example, a PC (Personal Computer). The memory may be, for example, a hard disk drive (HDD) or a solid state drive (SSD). Note that the memory may also include a dynamic random access memory (DRAM).

[0112] Under the control of the control unit 40, the data input unit 10 acquires data related to a print job from an external device (not shown) and records the acquired print job in memory or the like. The print job includes job commands including a print mode, image data of the image to be printed, various setting data, etc. When the print job is executed, the data input unit 10 reads the image data from memory and outputs it to the head driving unit 30.

[0113] The inkjet recording unit 322 and the ink curing and drying device 323 have already been described with reference to FIG. 1, and therefore a description thereof will be omitted. The temperature detection unit 80 is made up of temperature sensors m1 to m4. The temperature sensors m1 to m4 have already been described with reference to FIG. The recording medium detection unit 50 has also been described with reference to FIG. 1, and so a description thereof will be omitted.

[0114] The control unit 40 includes a CPU (Central Processing Unit) 401, a ROM (Read Only Memory) 402, a RAM (Random Access Memory) 403, and a non-volatile storage 404.

[0115] The CPU 401 reads out program code of software that realizes each function according to this embodiment from the ROM 402, expands it in the RAM 403, and executes it. Variables, parameters, etc. that are generated during the calculation processing by the CPU 401 are temporarily written to the RAM 403.

[0116] The control unit 40 may include a processing device such as an MPU (Micro-Processing Unit) instead of the CPU 401. Furthermore, the control unit 40 may use both a CPU and an MPU. Furthermore, the control unit 40 may be configured with an FPGA (Field-Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), or the like.

[0117] The nonvolatile storage 404 may be, for example, a hard disk drive (HDD), a solid state drive (SSD), an optical disk, or a nonvolatile memory card. In addition to an operating system (OS) and various parameters, software programs for implementing the various functions according to this embodiment are also recorded in this nonvolatile storage 404. The programs may be stored in the ROM 402.

[0118] The program is stored in the form of a computer-readable program code, and the CPU 401 sequentially executes operations in accordance with the program code. In other words, the ROM 402 or the non-volatile storage 404 is used as an example of a computer-readable non-transitory recording medium that stores a program to be executed by a computer.

[0119] The supply unit 220, temperature controlled transport drum 310, recording mechanism 320, transport path switching unit 20, reversing mechanism 330, and discharge mechanism 410 have already been described with reference to FIG. 1, and therefore further description will be omitted.

[0120] <Examples of transport routes that can be switched by the transport route switching unit> Next, the transport paths switched by the transport path switching unit 20 will be described. Fig. 4 is a diagram showing an example of the transport paths switched by the transport path switching unit 20. Fig. 4 shows a simplified version of the inkjet recording apparatus 1 shown in Fig. 1. In Fig. 4, parts corresponding to those in Fig. 1 are given the same reference numerals, and duplicated explanations will be omitted.

[0121] In this embodiment, the transport path switching unit 20 switches the transport path of the recording medium P to any one of the following first to third transport paths based on the control of the control unit 40.

[0122] First transport path: A path that passes through position B, position C, position D, position E, position F, and position B in this order, and then returns to position C. Second transport path: A path that passes through positions B, C, D, and E in this order and then returns to position C. Third transport path: A path that passes through positions C and D and is discharged onto the discharge tray 431.

[0123] The first transport path is the path indicated by the dashed arrow in FIG. 4. The first transport path is a path along which the recording medium P fed from the supply device 200 is transported by the temperature-controlled transport cylinder 310, the temperature-controlled recording cylinder 321, the first and second reversing cylinders 331 and 332 of the reversing mechanism 330, and the temperature-controlled transport cylinder 310. After an image is formed on the recording medium P transported along the first transport path by the inkjet recording unit 322, the recording medium P is reversed by the reversing mechanism 330 and returned to the temperature-controlled recording cylinder 321. In other words, this is a path that does not pass between the heater H2 and the temperature-controlled recording cylinder 321 (denoted as "directly below the heater" in the drawing). The first transport path is also a path along which the first side of the recording medium P is transported when double-sided printing is performed.

[0124] The second transport path is the path indicated by the dashed-dotted arrow in Fig. 4. The second transport path is a path along which the recording medium P fed from the supply device 200 is transported by the temperature-controlled transport cylinder 310 and the temperature-controlled recording cylinder 321. After an image is formed on the recording medium P transported along the second transport path by the inkjet recording unit 322, the recording medium P is transported for another round by the temperature-controlled recording cylinder 321. In other words, the second transport path is a path that passes between the heater H2 and the temperature-controlled recording cylinder 321. The second transport path is a path selected by the transport path switching unit 20 when transporting the recording medium P for the first round in the first printing mode or the second printing mode.

[0125] When the second transport path is selected by the transport path switching unit 20, the control unit 40 controls to turn off heating by the heater H2. Furthermore, the control unit 40 also controls to turn off detection by the recording medium detection unit 50. By performing such control by the control unit 40, the recording medium P transported by the temperature-controlled recording cylinder 321 for the first time can be prevented from being heated by the heater H2. Furthermore, the recording medium P transported by the temperature-controlled recording cylinder 321 for the first time can be prevented from being detected by the recording medium detection unit 50. In other words, it is possible to prevent the recording medium P that should make another rotation around the temperature-controlled recording cylinder 321 from being erroneously transported to the discharge mechanism 410.

[0126] That is, according to this embodiment, in a first printing mode such as the after-white mode or the background printing mode, the recording medium P on which the ink is not cured can be returned to the position of the inkjet recording unit 322 without being handed over to the reversing mechanism 330. In other words, it is possible to prevent the uncured ink from adhering to the reversing mechanism 330, and to form an image on the recording medium P in the second rotation.

[0127] Furthermore, according to this embodiment, in the image reading mode (second printing mode), the recording medium P on which an image has been formed can be rotated another time on the temperature-controlled recording drum 321 without being discharged from the discharge mechanism 410. This allows the control unit 40 to perform control to change the conveyance speed of the recording medium P between the first rotation in which image formation is performed and the second rotation in which image reading is performed.

[0128] More specifically, the control unit 40 can reduce the transport speed of the recording medium P during the second rotation compared to the first rotation. By performing such control by the control unit 40, it is possible to increase the resolution of image reading in the sub-scanning direction by the image reading unit 324. Therefore, using the image read by the image reading unit 324, the control unit 40 can detect ink ejection defects, deviations in ink landing positions, ink density, etc. with high accuracy.

[0129] Furthermore, in the image reading mode, the present embodiment can prevent the recording medium P on which an image has been formed before image reading by the image reading unit 324 from being discharged from the discharge mechanism 410. Therefore, the present embodiment can save the user the trouble of setting the recording medium P, on which the image is to be read, back into the supply device 200.

[0130] The third transport path is indicated by a solid arrow in Fig. 4. The third transport path is a path along which the recording medium P on which an image has been formed in the first rotation of transport or on one side (front side) of which an image has been formed is transported by the temperature-controlled recording cylinder 321 and the discharge mechanism 410.

[0131] In the first printing mode, an image is formed in white ink on the recording medium P transported through the third transport path by the inkjet recording unit 322, and then the recording medium P is subjected to a fixing process by the ink curing and drying device 323. Then, the recording medium P after the fixing process is discharged to a discharge tray 431 by the discharge mechanism 410.

[0132] In the second print mode, the recording medium P transported through the third transport path is discharged onto the discharge tray 431 by the discharge mechanism 410 after the image reading unit 324 has read the image on the recording medium P.

[0133] <Transport control process by inkjet recording device> Next, a transport control process performed by the inkjet recording apparatus 1 according to this embodiment will be described. Fig. 5 is a flowchart showing an example of the procedure for the transport control process when the first print mode is set. Fig. 6 is a flowchart showing an example of the procedure for the transport control process when the second print mode is set.

[0134] [Transport control process in first print mode] First, the transport control process when the first print mode is set will be described with reference to Fig. 5. As described above, the first print mode is a print mode in which the inkjet recording unit 322 forms an image on the same side of the recording medium P during the first and second rotations of transport of the recording medium P. The first print mode includes a background printing mode and a white-after mode.

[0135] First, the supply section 220 of the supply device 200 (see FIG. 1) transports the recording medium P to the temperature-controlled transport cylinder 310 (step S1). Hereinafter, the notation "step" in step Sn (n is a natural number equal to or greater than 2) may be omitted. Next, the temperature-controlled transport cylinder 310 transports the recording medium P to the temperature-controlled recording cylinder 321 (S2). Next, the inkjet recording section 322 forms an image (ejects ink) on the recording medium P transported by the temperature-controlled recording cylinder 321 (S3). The recording medium P with the image formed on its surface is transported along the outer circumferential surface of the temperature-controlled recording cylinder 321 without undergoing a fixing process by the ink curing / drying device 323.

[0136] Next, under the control of the control unit 40, the transport path switching unit 20 sets the transport destination of the recording medium P to the temperature-controlled recording cylinder 321 (S4). By performing the processing of step S4, the recording medium P makes another revolution around the outer circumferential surface of the temperature-controlled recording cylinder 321. Next, the control unit 40 controls to turn off heating by the heater H2 and detection by the recording medium detection unit 50 (S5). By performing the control of step S5, the recording medium P transported along the temperature-controlled recording cylinder 321 is prevented from being heated by the heater H2. Furthermore, by performing the processing of step S5, the recording medium P is prevented from being detected by the recording medium detection unit 50. This prevents the detected recording medium P from being discharged to the discharge tray 431 by the discharge mechanism 410.

[0137] Next, the recording medium P transported along the temperature-controlled recording cylinder 321 passes directly below the heater H2 and again reaches the position of the inkjet recording unit 322 (S6). When the recording medium P passes directly below the heater H2, the intake section 321s (see FIG. 2) of the temperature-controlled recording cylinder 321 generates a suction force under the control of the control unit 40. As a result, the recording medium P is attracted to and held on the outer peripheral surface of the temperature-controlled recording cylinder 321. On the other hand, when the transport destination set by the transport path switching unit 20 is the first reversing cylinder 331 of the reversing mechanism 330, the control unit 40 does not generate a suction force in the intake section 321s. This control by the control unit 40 allows the recording medium P to be smoothly transferred from the temperature-controlled recording cylinder 321 to the first reversing cylinder 331.

[0138] Next, the inkjet recording unit 322 forms a second image on the recording medium P (S7). When the printing mode is the background printing mode, the inkjet recording unit 322 forms an image on the recording medium P on which a background has already been formed using white ink or the like. When the printing mode is the back white mode, the inkjet recording unit 322 forms an image using white ink on the recording medium P on which an image has already been formed.

[0139] Next, the ink curing and drying device 323 performs a fixing process on the recording medium P (S8). Next, the transport path switching unit 20 switches the transport destination of the recording medium P to the cylinder 411 of the discharge mechanism 410 (S9). Next, the discharge mechanism 410 discharges the recording medium P to the discharge tray 431 (S10). After the processing of step S10, the transport control process when the first print mode is set ends.

[0140] In the above-described embodiment, in a first printing mode such as a background printing mode or a white-after printing mode, the recording medium P is conveyed another round along the temperature-controlled recording cylinder 321 with heating by the heater H2 turned off. Therefore, according to this embodiment, printing in the first printing mode can be achieved while preventing the recording medium P from being heated by the heater H2 and without temporarily discharging the recording medium P on which an image has been formed onto the discharge tray 431. Therefore, according to this embodiment, it is possible to save the user the trouble of loading the recording medium P into the supply device 200 again when printing in the first printing mode.

[0141] Furthermore, in the embodiment described above, the recording medium P on which an image has been formed during the first rotation of transport makes another rotation around the outer circumferential surface of the temperature-controlled recording cylinder 321 without undergoing fixing processing by the ink curing and drying device 323. In other words, according to this embodiment, the image is formed on the recording medium P during the second rotation without changing the wettability of the recording medium P on which the image has been formed during the first rotation. Therefore, it is possible to prevent the ink that constitutes the image formed the second time from being repelled by the recording medium P. This allows printing to be performed satisfactorily in the first print mode.

[0142] Furthermore, in the above-described embodiment, the recording medium P on which the ink is not cured is not transported to the reversing mechanism 330. Therefore, it is possible to prevent the uncured ink on the recording medium P from adhering to the first reversing cylinder 331 of the reversing mechanism 330.

[0143] [Transport control process in second print mode] Next, the transport control of the recording medium P by the inkjet recording apparatus 1 according to this embodiment when the second print mode is set will be described with reference to Fig. 6. As described above, the second print mode includes the image reading mode.

[0144] 5, the process from step S11 to S13 is the same as the process from step S1 to S3 in Fig. 5, and therefore a description thereof will be omitted. After the image is formed on the recording medium P in step S13, the ink curing and drying device 323 performs a fixing process on the recording medium P (S14). Next, the transport path switching unit 20 sets the destination of the recording medium P to the temperature-controlled recording cylinder 321 based on the control of the control unit 40 (S15). By performing the process of step S15, the recording medium P makes another revolution around the outer circumferential surface of the temperature-controlled recording cylinder 321.

[0145] Next, the control unit 40 controls to turn off heating by the heater H2 and to turn off detection by the recording medium detection unit 50 (S16). Next, the control unit 40 executes control to change the conveying speed of the recording medium P by the temperature controlled recording cylinder 321 to a low speed (S17). More specifically, the control unit 40 reduces the conveying speed of the recording medium P to a speed that allows the image reading unit 324 to read an image at high resolution.

[0146] The control unit 40 changes the transport speed of the recording medium P from after an image is formed on the recording medium P during the first rotation of the transport until the image is read by the image reading unit 324 during the second rotation. In other words, the control unit 40 changes the transport speed of the recording medium P during the time until the recording medium P on which the image has been formed reaches the position of the image reading unit 324 again.

[0147] Furthermore, the control to reduce the conveying speed during the second rotation of the conveyance may be performed when the printing mode is the first printing mode. When the printing mode is the first printing mode, the control unit 40 changes the conveying speed during the period from after an image is formed on the recording medium P during the first rotation of the conveyance until an image is formed by the inkjet recording unit 322 during the second rotation. In other words, the control unit 40 changes the conveying speed of the recording medium P during the period from when an image has been formed on the recording medium P until the recording medium P reaches the position of the inkjet recording unit 322 again.

[0148] Next, the recording medium P being transported on the temperature controlled recording cylinder 321 reaches the position of the image reading unit 324 (S18). Next, the image reading unit 324 reads the recording medium P on which the image has been formed (S19). Next, the transport path switching unit 20 switches the transport destination of the recording medium P to the cylinder 411 of the discharge mechanism 410 based on the control of the control unit 40 (S20). Next, the discharge mechanism 410 discharges the recording medium P to the discharge tray 431 (S21). After the processing of step S21, the transport control processing when the second print mode is set ends.

[0149] In the above-described embodiment, in a second printing mode such as an image reading mode, the recording medium P is conveyed another round along the temperature-controlled recording cylinder 321 with heating by the heater H2 turned off. Therefore, according to this embodiment, printing in the second printing mode can be achieved without temporarily discharging the recording medium P on which an image has been formed onto the discharge tray 431, while preventing heating of the recording medium P by the heater H2. Therefore, according to this embodiment, the user can be saved the trouble of loading the recording medium P into the supply device 200 again when printing in the second printing mode.

[0150] In the above-described embodiment, the control unit 40 changes the conveying speed of the recording medium P during the second rotation to a speed slower than the conveying speed during the first rotation. Therefore, according to this embodiment, the resolution of the reading of the recording medium P performed by the image reading unit 324 during the second rotation can be improved.

[0151] In addition, the control unit 40 can increase the resolution of the image formed on the recording medium P by the inkjet recording unit 322 in the second round by controlling the conveying speed of the recording medium P to be slower in the second round, for example, when the trailing white mode is set.

[0152] Furthermore, in the above-described embodiment, by adding the head 322W that ejects white ink to the inkjet recording unit 322, printing in either the background printing mode or the after-white mode becomes possible. In other words, there is no need to provide a dedicated mechanism for printing in the background printing mode or the after-white mode. Therefore, according to this embodiment, it is possible to prevent the inkjet recording apparatus 1 from becoming larger.

[0153] In the above-described embodiment, an example was given in which the ink heads in the inkjet recording unit 322 are arranged in the transport direction in the order W, Y, M, C, and K, but the present invention is not limited to this. The head 322W that ejects color inks may be provided downstream of the head 322K that ejects black ink, for example.

[0154] Furthermore, in the above-described embodiment, an example was given in which the recording medium detection unit 50 was provided upstream of the heater H2, but the present invention is not limited to this. The recording medium detection unit 50 may also be provided downstream of the heater H2. This makes it possible to determine the position of the recording medium P when the conveyance of the recording medium P stops when the rear end of the recording medium P passes the position of the heater H2. Furthermore, the recording medium detection unit 50 may also be provided both upstream and downstream of the heater H2.

[0155] Furthermore, in the above-described embodiment, an example was given in which the inkjet recording apparatus 1 is provided with the image reading unit 324, but the present invention is not limited to this. The inkjet recording apparatus according to the present invention may be configured without an image reading unit. In an inkjet recording apparatus without an image reading unit, only control related to the first print mode is performed.

[0156] Furthermore, the above-described embodiments and variants provide detailed and specific descriptions of the configurations of the devices and systems in order to clearly explain the present invention, and are not necessarily limited to those having all of the configurations described.

[0157] 3, the control lines or information lines shown by solid lines are those considered necessary for explanation, and do not necessarily show all control lines or information lines in the product. In reality, it can be considered that almost all components are interconnected.

[0158] Furthermore, in this specification, processing steps describing chronological processing include not only processing that is performed chronologically in the order described, but also processing that is not necessarily performed chronologically but is performed in parallel or individually (for example, parallel processing or processing by objects). [Explanation of symbols]

[0159] 1...inkjet recording device, 20...conveyance path switching unit, 40...control unit, 50...recording medium detection unit, 80...temperature detection unit, 300...recording device, 310...temperature controlled conveying cylinder, 320...recording mechanism, 321...temperature controlled recording cylinder, 322...inkjet recording unit, 323...ink curing and drying device, 324...image reading unit, 330...reversing mechanism, 331...first reversing cylinder, 332...second reversing cylinder, 400...discharge device, 410...discharge mechanism, 431...discharge tray, H1, H2...heater

Claims

1. an image forming unit that forms an image by ejecting ink onto a recording medium; a cylindrical transport mechanism that transports the recording medium; a heating unit that heats an outer peripheral surface of the conveying mechanism; a switching unit that switches a transport path of the recording medium between a first transport path that does not pass between the transport mechanism and the heating unit and a second transport path that passes between the transport mechanism and the heating unit; a control unit that controls the switching unit to switch the transport path in accordance with a print mode, The control unit stops heating by the heating unit when causing the switching unit to select the second transport path. Inkjet recording device.

2. The first transport path is a path along which the recording medium is transported along the outer circumferential surface of the transport mechanism and a reversing mechanism that reverses the recording medium, and then returns to the transport mechanism. The inkjet recording apparatus according to claim 1 .

3. The printing mode in which the control unit causes the switching unit to select the first transport path is a first printing mode in which the image forming unit forms an image on the same side of the recording medium during each of the first and second revolutions of the transport of the recording medium by the transport mechanism, or a second printing mode in which the transport speed of the recording medium is made different during the first and second revolutions of the transport of the recording medium by the transport mechanism. The inkjet recording apparatus according to claim 2 .

4. a fixing unit that fixes the ink onto the recording medium by curing the ink that has landed on the recording medium, When the printing mode is the first printing mode, the control unit does not cause the fixing unit to fix the image formed on the recording medium in the first rotation, and causes the recording medium to be transported along the first transport path while the ink that has landed on the recording medium is in an uncured state. The inkjet recording apparatus according to claim 3 .

5. The fixing unit performs a fixing process on the recording medium on which the image has been formed by the image forming unit during the second rotation. The inkjet recording apparatus according to claim 4 .

6. The control unit changes the conveying speed of the recording medium by the conveying mechanism in the second rotation to a speed slower than the conveying speed in the first rotation in the first printing mode or the second printing mode. The inkjet recording apparatus according to claim 5 .

7. an image reading unit that reads the recording medium on which the image has been formed by the image forming unit and generates a read image; The second printing mode is an image reading mode in which the image reading unit reads the image on the recording medium after the image forming unit forms the image on the recording medium.

7. The inkjet recording apparatus according to claim 6.

8. The control unit changes the conveying speed until the recording medium on which the image is formed in the first rotation reaches the position of the image reading unit. The inkjet recording apparatus according to claim 7 .

9. The control unit changes the conveying speed until the recording medium on which the image is formed in the first rotation reaches the position of the image forming unit.

7. The inkjet recording apparatus according to claim 6.

10. a recording medium detection unit that detects the recording medium entering between the conveying mechanism and the heating unit; When the control unit causes the switching unit to select the second transport path, the control unit stops detection by the recording medium detection unit. The inkjet recording apparatus according to claim 5 or 9.

11. the conveying mechanism further includes a suction unit that sucks the recording medium conveyed along an outer circumferential surface of the conveying mechanism; When the control unit causes the switching unit to select the second transport path, the control unit causes the suction unit to suck the recording medium into the transport mechanism. The inkjet recording apparatus according to claim 10.

12. an image forming procedure for forming an image by ejecting ink onto a recording medium; a transport procedure in which a cylindrical transport mechanism transports the recording medium; a heating step in which a heating unit heats an outer peripheral surface of the conveying mechanism; a switching step in which a switching unit switches a transport path of the recording medium between a first transport path that does not pass between the transport mechanism and the heating unit and a second transport path that passes between the transport mechanism and the heating unit; a control procedure for controlling the switching of the transport path by the switching unit in accordance with a print mode, In the control procedure, when the switching unit selects the second transport path, the heating unit stops heating. Transport control method.

Images