Patent Grant
10632763
The present application claims priority under 35 U.S.C. § 119 to Japanese Patent Applications Nos. 2017-104352 and 2017-104353, each filed on May 26, 2017. The contents of these applications are incorporated herein by reference in their entirety.
The present disclosure relates to a decurling device and an inkjet recording apparatus.
An inkjet recording apparatus includes a formation means, an acquisition means, a drying means, and a control means. The formation means forms an image according to recorded information by ejecting ink toward a recording medium. The acquisition means acquires based on the recorded information a distribution of ink ejection amounts of ink to be ejected in a direction across a sheet conveyance direction of the recording medium with the image formed thereon by the formation means. The drying means dries the recording medium with the image formed thereon by the formation means. The drying means includes a plurality of blowers and a plurality of partition walls. The blowers send heat of a heat source toward the recording medium. The partition walls stand in the sheet conveyance direction of the recording medium between a changing means and the recording medium and partition wind generated by the blowers. The control means performs control on the changing means according to the distribution of the ink ejection amounts acquired by the acquisition means so that drying temperature is higher in a region of the recording medium having a larger ink ejection amount than in a region thereof having a smaller ink ejection amount.
According to a first aspect of the present disclosure, a decurling device includes a decurler. A sheet is conveyed to the decurler. The decurler includes a first roller, a rotary member, and a heat source. The first roller is supported in a rotatable manner. The rotary member is supported in a rotatable manner. The heat source is disposed at the first roller to heat the first roller. The first roller and the rotary member rotate while holding the sheet therebetween to convey the sheet.
According to another aspect of the present disclosure, an inkjet recording apparatus includes the above decurling device and an image forming device.
Description will be made below about embodiments of the present disclosure with reference to the accompanying drawings. Note that elements in the drawings that are the same or equivalent are labelled using the same reference signs and description thereof is not repeated.
The following describes an inkjet recording apparatus 1 according to a first embodiment of the present disclosure with reference to
As illustrated in
The casing 10 accommodates the accommodation section 12, the first conveyor device 20, the image forming device 30, the second conveyor device 40, the third conveyor device 50, the fourth conveyor device 60, the ejection device 70, and the returning device 80. The exit tray 11 is disposed on an outer surface of the casing 10.
The accommodation section 12 accommodates sheets S. The accommodation section 12 is for example a cassette. Examples of the sheets S include plain paper, thick paper, overhead projector (OHP) sheets, envelopes, postcards, and invoice sheets.
The first conveyor device 20 feeds a sheet S accommodated in the accommodation section 12. Specifically, the first conveyor device 20 includes a feeding roller 21, a feeding passage 22, a first roller 23, and a registration roller 24. The feeding roller 21 picks up the sheet S accommodated in the accommodation section 12 and feeds the picked one to the feeding passage 22. The feeding passage 22 is located between the accommodation section 12 and the image forming device 30. The first roller 23 is disposed on the feeding passage 22 and conveys the sheet S fed by the feeding roller 21 to the registration roller 24. The registration roller 24 is located upstream of the image forming device 30 in terms of a sheet conveyance direction X of the sheet S and directly before the image forming device 30. The sheet conveyance direction X of the sheet S refers to a direction in which the sheet S moves in the inkjet recording apparatus 1 when the inkjet recording apparatus 1 executes a job for image formation on the sheet S. The registration roller 24 feeds the sheet S conveyed by the first roller 23 to the image forming device 30 in synchronization with timing of image formation by the image forming device 30.
The image forming device 30 is disposed downstream of the first conveyor device 20 in terms of the sheet conveyance direction X. The image forming device 30 ejects ink. Specifically, the image forming device 30 includes a plurality of heads and the heads eject ink.
The image forming device 30 ejects ink toward the sheet S to form an image on the sheet S. Examples of colors of the ink include black, cyan, magenta, and yellow. The ink is for example a water-based ink.
The second conveyor device 40 is disposed opposite to the image forming device 30. Specifically, the second conveyor device 40 includes a pair of second rollers 41, a first belt 42, and a first suction section 43. The second rollers 41 are spaced from each other in terms of the sheet conveyance direction X. The first belt 42 is an endless belt. The first belt 42 is wound between the second rollers 41. The first belt 42 has a plurality of holes. The first belt 42 is rotated by rotation of the second rollers 41. The first suction section 43 is disposed within a loop of the first belt 42. The first suction section 43 sucks air through the holes of the first belt 42.
The second conveyor device 40 conveys the sheet S in the following manner.
The sheet S fed by the registration roller 24 is placed on the first belt 42. The first suction section 43 sucks air. As a result of suction, the sheet S adheres to the first belt 42 with a suction side S2 thereof in contact with the first belt 42. The first belt 42 rotates to convey the sheet S in the sheet conveyance direction X. In the following description, a side of the sheet S that is opposite to the suction side S2 will be referred to as an image formation side S1.
The image forming device 30 ejects ink toward the sheet S placed on the first belt 42. The image forming device 30 ejects ink toward the image formation side S1 of the sheet S to form an image on the image formation side S1. That is, frontside printing of duplex printing is performed on the sheet S. The image is formed from ink attached to the image formation side S1.
The third conveyor device 50 is disposed downstream of the image forming device 30 in terms of the sheet conveyance direction X. The third conveyor device 50 is disposed also downstream of the second conveyor device 40 in terms of the sheet conveyance direction X. The third conveyor device 50 conveys the sheet S to air-dry ink attached to the sheet S. Specifically, the third conveyor device 50 includes a pair of third rollers 51, a second belt 52, and a second suction section 53. The third rollers 51 are spaced from each other in terms of the sheet conveyance direction X. The second belt 52 is wound between the third rollers 51. The second belt 52 has a plurality of holes. The second belt 52 is rotated by rotation of the third rollers 51. The second suction section 53 is disposed within a loop of the second belt 52. The second suction section 53 sucks air through the holes of the second belt 52.
The third conveyor device 50 conveys the sheet S in the following manner.
The sheet S fed by the second conveyor device 40 is placed on the second belt 52. The second suction section 53 sucks air to cause the sheet S to adhere to the second belt 52 with the suction side S2 thereof in contact with the second belt 52. The second belt 52 rotates to covey the sheet S in the sheet conveyance direction X.
During conveyance of the sheet S by the third conveyor device 50, ink attached to the image formation side S1 of the sheet S is dried through exposure to the air. In the above configuration, ink drying can be accelerated for example by increasing the size of the third conveyor device 50 to increase a conveyance distance of the sheet S in the third conveyor device 50.
The fourth conveyor device 60 is disposed downstream of the third conveyor device 50 in terms of the sheet conveyance direction X. The fourth conveyor device 60 will be described later in detail.
The ejection device 70 is disposed downstream of the fourth conveyor device 60 in terms of the sheet conveyance direction X. The ejection device 70 ejects the sheet S having passed through the image forming device 30 out of the casing 10. Specifically, the ejection device 70 includes an ejection passage 71 and an ejection roller 72. The ejection passage 71 is located between the fourth conveyor device 60 and the exit tray 11. The ejection roller 72 ejects the sheet S conveyed through the ejection passage 71 onto the exit tray 11.
The returning device 80 is disposed downstream of the fourth conveyor device 60 in terms of the sheet conveyance direction X. Specifically, the returning device 80 includes a paper reversing passage 81, a paper returning passage 82, a second diverging guide 83, a reversing roller 84, and a returning roller 85.
The paper reversing passage 81 is connected to the fourth conveyor device 60. The paper returning passage 82 has ends one of which is connected to a joint part 81a between the paper reversing passage 81 and the fourth conveyor device 60. The other end of the paper returning passage 82 is connected to the feeding passage 22. A joint part 82a between the other end of the paper returning passage 82 and the feeding passage 22 is located upstream of the registration roller 24 in terms of the sheet conveyance direction X.
The second diverging guide 83 is disposed at the joint part 81a. The second diverging guide 83 is supported pivotally. The second diverging guide 83 is changeable in posture between a first guide posture and a second guide posture. The first guide posture refers to a posture of the second diverging guide 83 for which communication between the paper reversing passage 81 and the paper returning passage 82 is cut and communication between the paper reversing passage 81 and the fourth conveyor device 60 is established. The second guide posture refers to a posture of the second diverging guide 83 for which communication between the paper reversing passage 81 and the fourth conveyor device 60 is cut and communication between the paper reversing passage 81 and the paper returning passage 82 is established.
The reversing roller 84 is disposed on the paper reversing passage 81. The returning roller 85 is disposed on the paper returning passage 82.
The following describes a sequence in which the returning device 80 conveys the sheet S from the fourth conveyor device 60 to the feeding passage 22.
First, the second diverging guide 83 takes the first guide posture. As a result of the second diverging guide 83 being in the first guide posture, the second diverging guide 83 guides the sheet S from the fourth conveyor device 60 to the paper reversing passage 81.
Subsequently, the reversing roller 84 returns the sheet S from the paper reversing passage 81 to the second diverging guide 83.
Next, the second diverging guide 83 takes the second guide posture. As a result of the second diverging guide 83 being in the second guide posture, the second diverging guide 83 guides the sheet S from the paper reversing passage 81 to the paper returning passage 82.
Subsequently, the returning roller 85 conveys the sheet S from the paper returning passage 82 to the feeding passage 22.
The sheet S is re-conveyed to the image forming device 30 by the returning device 80.
The sheet S conveyed by the returning device 80 has been reversed between a front side (image formation side S1) and a back side (suction side S2). Also, the sheet S conveyed by the returning device 80 has been reversed in position between a leading edge and a trailing edge thereof in the sheet conveyance direction X. Accordingly, the sheet S is sucked to the first belt 42 with the image formation side S1 thereof in contact with the first belt 42. The image forming device 30 then ejects ink toward the suction side S2 of the sheet S to form an image. That is, backside printing of duplex printing is performed on the sheet S.
The following describes the fourth conveyor device 60 and the first diverging guide 90 with reference to
As illustrated in
The decurling device 61 includes a first decurler 63 and a second decurler 64.
The sheet S is conveyed to the first decurler 63. The first decurler 63 is disposed downstream of the image forming device 30 in terms of the sheet conveyance direction X. The first decurler 63 is disposed also downstream of the third conveyor device 50 in terms of the sheet conveyance direction X. Accordingly, the sheet S having passed along the third conveyor device 50 is fed to the first decurler 63.
Specifically, the first decurler 63 includes a first decurling roller 63a and a second decurling roller 63b. The first and second decurling rollers 63a and 63b are supported in a rotatable manner. The first and second decurling rollers 63a and 63b rotate while holding the sheet S therebetween to convey the sheet S. Specifically, the first and second decurling rollers 63a and 63b rotate while holding the sheet S between respective outer circumferential surfaces thereof.
When the first and second decurling rollers 63a and 63b hold the sheet S therebetween, a part of the sheet S located between the first and second decurling rollers 63a and 63b is flattened. As a result, curling of the sheet S can be mitigated. Curling of the sheet S means curving of an edge of the sheet S toward the suction side S2 due to ink attachment to the image formation side S1 of the sheet S.
The first and second decurling rollers 63a and 63b are coated with either or both of ceramic particles and particles such as glass beads. In the above configuration, a contact area of the sheet S in contact with a unit area of the first decurling roller 63a can be reduced. Also, a contact area of the sheet S in contact with a unit area of the second decurling roller 63b can be reduced. As a result, transfer of ink attached to the sheet S to the first and second decurling rollers 63a and 63b can be inhibited.
The sheet S is conveyed to the second decurler 64. The second decurler 64 is disposed downstream of the image forming device 30 in terms of the sheet conveyance direction X. The second decurler 64 is disposed also downstream of the first decurler 63 in terms of the sheet conveyance direction X.
Specifically, the second decurler 64 includes a first dryer roller 64a, a second dryer roller 64b, a first heater 64c, and a first detection section 64d, as illustrated in
The first and second dryer rollers 64a and 64b are coated with either or both of ceramic particles and particles such as glass beads. In the above configuration, a contact area of the sheet S in contact with a unit area of the first dryer roller 64a can be reduced. Also, a contact area of the sheet S in contact with a unit area of the second dryer roller 64b can be reduced. As a result, transfer of ink attached to the sheet S to the first and second dryer rollers 64a and 64b can be inhibited.
The first heater 64c is for example a halogen heater. Specifically, the first heater 64c includes a first power source 64g, a first heat source 64e, and a first heat source casing 64f that accommodates the first heat source 64e.
The first heat source 64e is a member capable of heat generation. The first heat source 64e is for example a filament.
The first heat source 64e is disposed at the first dryer roller 64a. The first heat source 64e is embedded in the first dryer roller 64a in the present embodiment. A configuration in which the first heat source 64e is embedded in the first dryer roller 64a encompasses a configuration in which the first dryer roller 64a has a hollow space in which the first heat source 64e is disposed and a configuration in which the first dryer roller 64a has a substantially hollow cylindrical shape with the first heat source 64e disposed in a space surrounded by an inner circumferential surface of the first dryer roller 64a. The first heat source 64e is mounted for example at either or both of the first dryer roller 64a and a first shaft member. The first shaft member is inserted through the first dryer roller 64a to support the first dryer roller 64a in a rotatable manner.
The first power source 64g supplies power to the first heat source 64e to activate the first heat source 64e. The first power source 64g is an electric power supply in the present embodiment. In the above configuration, the first power source 64g supplies electric power to the first heat source 64e to activate the first heat source 64e. As a result of power supply, the first heat source 64e generates heat to increase the temperature of the first dryer roller 64a.
The first detection section 64d detects the temperature of the first dryer roller 64a. Detection of the temperature of the first dryer roller 64a encompasses detection of the temperature of the first heat source 64e and detection of the temperature of the first heat source casing 64f. The first detection section 64d is for example constituted by a thermistor.
The guide section 62 guides the sheet S. Specifically, the guide section 62 includes a first guide passage 65, a second guide passage 66, a third guide passage 67, and a third diverging guide 68.
The first guide passage 65 is located upstream of the second decurler 64 in terms of the sheet conveyance direction X. The first guide passage 65 has ends one of which is connected to the first decurler 63. The other end of the first guide passage 65 is connected to the second decurler 64.
The second guide passage 66 is located downstream of the second decurler 64 in terms of the sheet conveyance direction X. The second guide passage 66 has ends one of which is connected to the second decurler 64. Accordingly, the second decurler 64 is located between the second and first guide passages 66 and 65.
The other end of the second guide passage 66 is connected to the returning device 80. Specifically, the other end of the second guide passage 66 is connected to the paper reversing passage 81. The ejection passage 71 is connected to a mid-part of the second guide passage 66.
The third guide passage 67 connects the first and second guide passages 65 and 66 directly not via the second decurler 64. The third guide passage 67 has ends one of which is connected to a mid-part of the first guide passage 65. The other end of the third guide passage 67 is connected to a mid-part of the second guide passage 66. In the above configuration, the third guide passage 67 diverges from the first guide passage 65 and leads to the second guide passage 66.
A joint part 67a between the third and second guide passages 67 and 66 is located upstream of a joint part 66a between the second guide passage 66 and the ejection passage 71 in terms of the sheet conveyance direction X. In the above configuration, the sheet S having passed through the third guide passage 67 can be conveyed to the ejection passage 71 and ejected out onto the exit tray 11.
The third diverging guide (diverging guide) 68 is disposed at a joint part 65a between the first and third guide passages 65 and 67. The third diverging guide 68 is supported pivotally. The third diverging guide 68 is changeable in posture between a third guide posture and a fourth guide posture. The third guide posture refers to a posture of the third diverging guide 68 for which communication between the first and third guide passages 65 and 67 is cut and communication between the first guide passage 65 and the second decurler 64 is established. The fourth guide posture refers to a posture of the third diverging guide 68 for which communication between the first guide passage 65 and the second decurler 64 is cut and communication between the first and third guide passages 65 and 67 is established.
When the third diverging guide 68 is in the third guide posture, the sheet S is conveyed to the first guide passage 65, the second decurler 64, and the second guide passage 66 in the stated order.
By contrast, when the third diverging guide 68 is in the fourth guide posture, the sheet S is conveyed to the first guide passage 65, the third guide passage 67, and the second guide passage 66 in the stated order. In the above configuration, the sheet S is conveyed to the second guide passage 66 not via the second decurler 64 when the third diverging guide 68 is in the fourth guide posture.
The first diverging guide 90 is disposed at the joint part 66a. The first diverging guide 90 is supported pivotally. The first diverging guide 90 is changeable in posture between a fifth guide posture and a sixth guide posture. The fifth guide posture refers to a posture of the first diverging guide 90 for which communication between the second guide passage 66 and the ejection passage 71 is cut and communication between the second guide passage 66 and the returning device 80 is established. The sixth guide posture refers to a posture of the first diverging guide 90 for which communication between the second guide passage 66 and the returning device 80 is cut and communication between the second guide passage 66 and the ejection passage 71 is established.
When the first diverging guide 90 is in the fifth guide posture, the sheet S is conveyed from the second guide passage 66 to the returning device 80. Subsequently, backside printing is performed on the sheet S.
By contrast, when the first diverging guide 90 is in the sixth guide posture, the sheet S is conveyed from the second guide passage 66 to the ejection passage 71. Subsequently, the sheet S is ejected onto the exit tray 11.
As described with reference to
Furthermore, the first heat source 64e heats the first dryer roller 64a. In the above configuration, drying of ink attached to the sheet S can be accelerated by the heat of the first dryer roller 64a during conveyance of the sheet S in a manner that the first and second dryer rollers 64a and 64b rotate while holding the sheet S therebetween. As a result, sheet curling can be mitigated and occurrence of problems such as sheet edge folding and a sheet jam can be prevented.
When the first and second dryer rollers 64a and 64b hold the sheet S therebetween, a part of the sheet S located between the first and second dryer rollers 64a and 64b is flattened. As a result, curling of the sheet S can be mitigated.
Mitigation of sheet curling can achieve effective suction of the sheet S to the first belt 42 in backside printing on the sheet S. Consequently, a lift of an edge of the sheet S from the first belt 42 can be prevented. As a result, a situation in which the sheet S is rubbed against the image forming device 30 can be prevented. Thus, smooth backside printing on the sheet S can be achieved.
Furthermore, when the sheet S is heated by the first dryer roller 64a, moisture in ink attached to the sheet S evaporates. Thus, ink drying can be accelerated. As a result, need to air-dry ink attached to the sheet S in the third conveyor device 50 is reduced. This can enable reduction in a distance by which the third conveyor device 50 conveys the sheet S or omission of the third conveyor device 50. Thus, size reduction of the inkjet recording apparatus 1 can be achieved.
The following describes the second decurler 64 with reference to
As illustrated in
A portion of the first heat source casing 64f located opposite to the first heat source 64e is heated substantially uniformly to a specific temperature T. As a result, the first dryer roller 64a is heated to the specific temperature T. Note that the specific temperature T is determined in advance. The specific temperature T is a temperature suitable for accelerating drying of ink attached to the sheet S and is determined for example by an experiment.
When the first and second dryer rollers 64a and 64b hold the sheet S therebetween, the first dryer roller 64a is opposite to the image formation side S1 of the sheet S while the second dryer roller 64b is opposite to the suction side S2 thereof. Accordingly, the image formation side S1 of the sheet S is heated by the first dryer roller 64a.
The first and second dryer rollers 64a and 64b rotate while holding the sheet S therebetween. As a result, the sheet S passes between the first and second dryer rollers 64a and 64b while receiving heat from the first dryer roller 64a.
As described above with reference to
The following describes the inkjet recording apparatus 1 with reference to
As illustrated in
The storage 100 includes a storage device. The storage device includes a main storage device (e.g., semiconductor memory) such as read only memory (ROM) or random access memory (RAM) and may further include an auxiliary storage device (e.g., a hard disk drive). Either or both of the main storage device and the auxiliary storage device store therein various computer programs that are executed by the control device 110.
The storage 100 stores therein information indicating the specific temperature T.
The control device 110 includes a processor such as a central processing unit (CPU) or a micro processing unit (MPU). The control device 110 controls respective elements of the inkjet recording apparatus 1. Specifically, the processor executes computer programs stored in the storage device to control the first conveyor device 20, the image forming device 30, the second conveyor device 40, the third conveyor device 50, the fourth conveyor device 60, the ejection device 70, the returning device 80, the first diverging guide 90, and the storage 100.
The control device 110 includes a receiver 111, a calculator 112, a determination section 113, and a controller 114. Specifically, the processor executes computer programs stored in the storage device to function as the receiver 111, the calculator 112, the determination section 113, and the controller 114.
The receiver 111 receives image data. The image data is data representing an image that the image forming device 30 is to form on the sheet S. The receiver 111 receives for example the image data from an external computer. In a configuration in which the inkjet recording apparatus 1 includes an image reading section, the receiver 111 is capable of receiving the image data from the image reading section.
The calculator 112 acquires the image data from the receiver 111. The calculator 112 calculates an ink ejection amount based on the image data. Specifically, the ink ejection amount refers to an amount of ink that the image forming device 30 is to eject toward a region α of the sheet S located at a trailing edge S3 thereof as illustrated in
The determination section 113 determines based on the ink ejection amount calculated by the calculator 112 whether or not to activate the first heat source 64e. To activate the first heat source 64e means power supply by the first power source 64g to the first heat source 64e to increase the temperature of the first heat source 64e.
When the ink ejection amount calculated by the calculator 112 is larger than a specific reference amount, the determination section 113 determines to activate the first heat source 64e. By contrast, when the ink ejection amount calculated by the calculator 112 is equal to or smaller than the specific reference amount, the determination section 113 determines not to activate the first heat source 64e. Non-activation of the first heat source 64e means no power supply by the first power source 64g to the first heat source 64e. The specific reference amount indicates a maximum value of the ink ejection amount in the region α in a condition in which the sheet S can be smoothly conveyed with occurrence of problems such as a sheet jam prevented. The specific reference amount is determined for example by an experiment. Information representing the specific reference amount is stored in the storage 100 in advance.
The following describes an example of the specific reference amount with reference to
The trailing edge S3 of the sheet S comes first in backside printing on the sheet S. When the specific reference amount is set as in the above example, the trailing edge S3 of the sheet S can be prevented from coming into contact with the image forming device 30 in backside printing on the sheet S. Furthermore, unnecessary activation of the first heat source 64e can be reduced with a result that efficient activation of the first heat source 64e can be achieved.
Description about the controller 114 will be continued with reference to
The controller 114 is connected to the image forming device 30 to control the image forming device 30. Specifically, the controller 114 controls the image forming device 30 to eject ink toward the sheet S.
The controller 114 acquires the image data from the receiver 111. The controller 114 then controls the image forming device 30 based on the image data. In response, the image forming device 30 forms an image corresponding to the image data on the sheet S.
The controller 114 controls the first heat source 64e and the image forming device 30 based on a determination result by the determination section 113.
The controller 114 is connected to the second conveyor device 40 to control the second conveyor device 40. Specifically, the controller 114 controls the pair of second rollers 41, the first belt 42, and the first suction section 43.
The controller 114 is connected to the third conveyor device 50 to control the third conveyor device 50. Specifically, the controller 114 controls the pair of third rollers 51, the second belt 52, and the second suction section 53.
The controller 114 is connected to the guide section 62 to control the guide section 62. Specifically, the controller 114 controls the third diverging guide 68.
The controller 114 is connected to the first decurler 63 to control the first decurler 63. Specifically, the controller 114 controls the first and second decurling rollers 63a and 63b.
The controller 114 is connected to the second decurler 64 to control the second decurler 64. Specifically, the controller 114 controls the first and second dryer rollers 64a and 64b, the first heater 64c, and the first detection section 64d.
The controller 114 is connected to the ejection device 70 to control the ejection device 70. Specifically, the controller 114 controls the ejection roller 72.
The controller 114 is connected to the returning device 80 to control the returning device 80. Specifically, the controller 114 controls the second diverging guide 83, the reversing roller 84, and the returning roller 85.
The controller 114 is connected to the first diverging guide 90 to control the first diverging guide 90.
A motor for example is connected through a gear and a clutch to conveyance members that convey the sheet S, such as the feeding roller 21, the first roller 23, the registration roller 24, the second roller 41, the third roller 51, the third diverging guide 68, the first and second decurling rollers 63a and 63b, the first and second dryer rollers 64a and 64b, the ejection roller 72, the second diverging guide 83, the reversing roller 84, the returning roller 85, and the first diverging guide 90. The controller 114 operates for example the gear, the clutch, and the motor to control operation of the conveyance members.
The following describes operation of the control device 110 with reference to
As illustrated in
The calculator 112 acquires the image data from the receiver 111 at Step S20. The calculator 112 calculates an ink ejection amount of ink to be ejected toward the region α of the sheet S located at the trailing edge S3 thereof.
At Step S30, the determination section 113 determines whether or not to activate the first heat source 64e based on the ink ejection amount calculated by the calculator 112. That is, the determination section 113 determines prior to image formation on the sheet S whether or not to activate the first heat source 64e.
When the ink ejection amount calculated by the calculator 112 is larger than the specific reference amount, the determination section 113 determines to activate the first heat source 64e. By contrast, when the ink ejection amount calculated by the calculator 112 is equal to or smaller than the specific reference amount, the determination section 113 determines not to activate the first heat source 64e.
When the determination section 113 determines to activate the first heat source 64e (Yes at Step S30), the routine proceeds to Step S40. When the determination section 113 determines not to activate the first heat source 64e (No at Step S30), the routine proceeds to Step S100.
At Step S40, the controller 114 activates the first heat source 64e.
At Step S50, the first detection section 64d detects the temperature of the first dryer roller 64a.
At Step S60, the controller 114 receives information indicating the temperature of the first dryer roller 64a from the first detection section 64d. When the controller 114 determines that the temperature of the first dryer roller 64a is equal to or higher than the specific temperature T (Yes at Step S60), the routine proceeds to Step S70. When the controller 114 determines that the temperature of the first dryer roller 64a is lower than the specific temperature T (No at Step S60), the routine returns to Step S50.
At Step S70, the image forming device 30 forms an image on the sheet S. Specifically, the controller 114 first controls the first conveyor device 20 to convey the sheet S accommodated in the accommodation section 12 toward the image forming device 30. Subsequently, the controller 114 controls the second conveyor device 40 to convey the sheet S under the image forming device 30. The controller 114 then controls the image forming device 30 to form an image on the sheet S based on the image data. In response, the image forming device 30 ejects ink toward the sheet S to form the image on the sheet S.
At Step S80, the first decurler 63 conveys the sheet S. Specifically, the controller 114 controls the third conveyor device 50 to convey the sheet S to the first decurler 63. Then, the first and second decurling rollers 63a and 63b of the first decurler 63 rotate while holding the sheet S therebetween to convey the sheet S. As a result, curling of the sheet S is mitigated.
At Step S90, the second decurler 64 conveys the sheet S. Specifically, the controller 114 controls the guide section 62 to guide the sheet S toward the second decurler 64. That is, the controller 114 causes the third diverging guide 68 to take the third guide posture. As a result, the third diverging guide 68 guides the sheet S to the second decurler 64. Then, the first and second dryer rollers 64a and 64b of the second decurler 64 rotate while holding the sheet S therebetween to convey the sheet S. Accordingly, the first dryer roller 64a at a temperature equal to or higher than the specific temperature T comes in contact with the image formation side S1 of the sheet S. As a result of contact, drying of ink attached to the sheet S can be accelerated. Thus, curling of the sheet S can be effectively mitigated.
The sheet S having passed between the first and second dryer rollers 64a and 64b reaches the second guide passage 66.
At Step S100, the image forming device 30 forms the image on the sheet S (see Step S70). Thus, the image is formed on the sheet S in a state in which the first heat source 64e is not activated.
At Step S110, the first decurler 63 conveys the sheet S (see Step S80).
At Step S120, the controller 114 controls the guide section 62 to guide the sheet S to the third guide passage 67. That is, the controller 114 causes the third diverging guide 68 to take the fourth guide posture. As a result, the sheet S is conveyed to the third guide passage 67 and the second guide passage 66 in the stated order not via the second decurler 64.
The sheet S having reached the second guide passage 66 at Step S90 or S120 may be conveyed to the ejection passage 71 to be ejected onto the exit tray 11. Alternatively, the sheet S having reached the second guide passage 66 may be conveyed to the paper reversing passage 81 and the paper returning passage 82 in the stated order for backside printing on the sheet S.
As described with reference to
When unnecessary activation of the first heat source 64e is reduced, the number of times that members composing the second decurler 64, such as the first and second dryer rollers 64a and 64b are heated can be reduced. As a result, the lifetime of the second decurler 64 can be extended.
In a situation in which the sheet S need not be heated, the sheet S can be conveyed not via the second decurler 64 as depicted at Step S120. This can reduce the number of times that the second decurler 64 is activated, and therefore, extend the lifetime of the second decurler 64.
The following describes variations of the second decurler 64 with reference to
As illustrated in
The number of the support rollers 64h is two in the first variation. The support rollers 64h are supported in a rotatable manner. The support rollers 64h are spaced from each other. The dryer belt 64i is an endless belt. The dryer belt 64i is wound between the support rollers 64h. The dryer belt 64i is supported in a rotatable manner. Specifically, the dryer belt 64i is supported by the support rollers 64h in a rotatable manner. The dryer belt 64i is rotated by rotation of the support rollers 64h while in contact with the support rollers 64h.
The first dryer roller 64a and the dryer belt 64i rotate while holding the sheet S therebetween to convey the sheet S. Specifically, the first dryer roller 64a and the dryer belt 64i rotate while holding the sheet S between the outer circumferential surface of the first dryer roller 64a and the outer surface of the dryer belt 64i. The outer surface of the dryer belt 64i refers to one of surfaces of the dryer belt 64i that is opposite to the other surface thereof in contact with the support rollers 64h.
The first dryer roller 64a holds the sheet S in cooperation with the dryer belt 64i between the first dryer roller 64a and a specific portion R of the dryer belt 64i. The specific portion R refers to a portion of the dryer belt 64i located at a position corresponding to the first dryer roller 64a that is not opposite to the support rollers 64h with the dryer belt 64i therebetween. In other words, the specific portion R is a portion of the dryer belt 64i that is out of contact with the support rollers 64h. In the above configuration, the first dryer roller 64a and the dryer belt 64i rotate while holding the sheet S between the first dryer roller 64a and the specific portion R of the dryer belt 64i to convey the sheet S.
The specific portion R of the dryer belt 64i receives pressure from the first dryer roller 64a to warp. As such, the first dryer roller 64a holds the sheet S in cooperation with the dryer belt 64i between the first dryer roller 64a and a warped portion of the dryer belt 64i.
As illustrated in
The support rollers 64h are spaced from one another. The support rollers 64h are not aligned. The number of the support rollers 64h is three in the second variation. In the second variation, two of the three support rollers 64h are disposed on a conveyance path of the sheet S while the other of the support rollers 64h is spaced apart from the conveyance path of the sheet S. The first dryer roller 64a and the dryer belt 64i rotate while holding the sheet S between the first dryer roller 64a and the specific portion R of the dryer belt 64i to convey the sheet S. That is, the first dryer roller 64a holds the sheet S in cooperation with the dryer belt 64i between the first dryer roller 64a and the warped portion of the dryer belt 64i.
As described with reference to
When the first dryer roller 64a and the dryer belt 64i hold the sheet S therebetween, the first dryer roller 64a is located opposite to the image formation side S1 of the sheet S. When the first dryer roller 64a and the dryer belt 64i hold the sheet S therebetween, the dryer belt 64i faces the suction side S2 of the sheet S. In the above configuration, the sheet S warps in a direction opposite to a curling direction while being conveyed through rotation of the first dryer roller 64a and the dryer belt 64i holding the sheet S therebetween. The curling direction refers to a direction in which the sheet S curls. As a result, effective mitigation of sheet curling can be achieved.
The following describes an inkjet recording apparatus 1 according to a second embodiment of the present disclosure with reference to
Specifically, the second decurler 64 includes the first dryer roller 64a, the second dryer roller 64b, the first heater 64c, a second detection section 64q, a second heater 64j, and a third detection section 64k, as illustrated in
The second detection section 64q detects the temperature of ends of the first dryer roller 64a. The ends of the first dryer roller 64a are parts of the first dryer roller 64a that do not overlap the first heat source 64e in terms of an axial direction Z1. The axial direction Z1 refers to a direction along the rotational axis Z of the first dryer roller 64a. Detection of the temperature of the ends of the first dryer roller 64a encompasses detection of the temperature of the first heat source 64e and detection of the temperature of ends of the first heat source casing 64f. The ends of the first heat source casing 64f refer to parts of the first heat source casing 64f that do not overlap the first heat source 64e in the axial direction Z1. The second detection section 64q is for example constituted by a thermistor.
The second heater 64j is for example a halogen heater. Specifically, the second heater 64j includes a second power source 64p, a second heat source 64m, and a second heat source casing 64n that accommodates the second heat source 64m.
The second heat source 64m is a member capable of heat generation. The second heat source 64m is for example a filament.
The second heat source 64m is disposed at the second dryer roller 64b. The second heat source 64m is embedded in the second dryer roller 64b in the present embodiment. Specifically, the second dryer roller 64b has a hollow space in which the second heat source 64m is disposed. The second heat source 64m is mounted for example at either or both of the second dryer roller 64b and a second shaft member. The second shaft member is inserted through the second dryer roller 64b to support the second dryer roller 64b in a rotatable manner.
The second power source 64p supplies power to the second heat source 64m to activate the second heat source 64m. When activated, the second heat source 64m generates heat to increase the temperature of the second dryer roller 64b. The second power source 64p may be identical with or different from the first power source 64g.
The third detection section 64k detects the temperature of a central part of the second dryer roller 64b. The central part of the second dryer roller 64b is a part of the second dryer roller 64b that overlaps the second heat source 64m in terms of the aforementioned axial direction Z1. Detection of the temperature of the central part of the second dryer roller 64b encompasses detection of the temperature of the second heat source 64m and detection of the temperature of a central part of the second heat source casing 64n. The central part of the second heat source casing 64n is a part of the second heat source casing 64n that overlaps the second heat source 64m in terms of the aforementioned axial direction Z1. The third detection section 64k is for example constituted by a thermistor.
As described with reference to
Furthermore, the first heat source 64e heats the first dryer roller 64a. The second heat source 64m heats the second dryer roller 64b. In the above configuration, when the first and second dryer rollers 64a and 64b rotate while holding the sheet S therebetween to convey the sheet S, drying of ink attached to the sheet S can be accelerated with use of heat of the first and second dryer rollers 64a and 64b. As a result, sheet curling can be mitigated and occurrence of problems such as sheet edge folding and a sheet jam can be prevented.
By heating the sheet S using the first and second dryer rollers 64a and 64b, ink drying can be accelerated by evaporating moisture in ink attached to the sheet S. As a result, need to air-dry ink attached to the sheet S in the third conveyor device 50 is reduced. This can enable reduction in a distance by which the third conveyor device 50 conveys the sheet S or omission of the third conveyor device 50. Thus, size reduction of the inkjet recording apparatus 1 can be achieved.
The following describes the second decurler 64 according to the second embodiment with reference to
As illustrated in
When the sheet S is held between the first and second dryer rollers 64a and 64b, the first heat sources 64e are located opposite to respective opposite edges U1 of the sheet S in terms of the axial direction Z1. The first heat sources 64e heat ends of the first dryer roller 64a. Specifically, the first heat sources 64e heat respective opposite ends of the first dryer roller 64a in terms of the axial direction Z1. As a result, the first heat sources 64e heat the respective opposite edges U1 of the sheet S in terms of the aforementioned axial direction Z1.
Parts of the first heat source casing 64f located opposite to the respective first heat sources 64e are heated substantially uniformly to a specific first temperature T1. As a result, respective parts of the first dryer roller 64a located opposite to the first heat sources 64e are heated to the specific first temperature T1. Note that the specific first temperature T1 is determined in advance. The specific first temperature T1 is a temperature suitable for acceleration of drying of ink attached to the opposite edges U1 of the sheet S, and is determined for example by an experiment.
As illustrated in
When the sheet S is held between the first and second dryer rollers 64a and 64b, the second heat source 64m is located opposite to a central part U2 of the sheet S in terms of the aforementioned axial direction Z1. The second heat source 64m heats the central part of the second dryer roller 64b in terms of the aforementioned axial direction Z1. As a result, the second heat source 64m heats the central part U2 of the sheet S in terms of the aforementioned axial direction Z1.
A part of the second heat source casing 64n that is located opposite to the second heat source 64m is heated substantially uniformly to a specific second temperature T2. As a result, a part of the second dryer roller 64b located opposite to the second heat source 64m is heated to the specific second temperature T2. Note that the specific second temperature T2 is determined in advance. The specific second temperature T2 is a temperature suitable for acceleration of drying ink attached to the central part U2 of the sheet S, and is determined for example by an experiment. The specific first and second temperatures T1 and T2 may be equal to or different from each other.
When the first and second dryer rollers 64a and 64b hold the sheet S therebetween, the first dryer roller 64a is opposite to the image formation side S1 of the sheet S while the second dryer roller 64b is opposite to the suction side S2 of the sheet S. The first dryer roller 64a accordingly heats the opposite edges U1 of the sheet S from the image formation side S1 thereof. By contrast, the second dryer roller 64b heats the central part U2 of the sheet S from the suction side S2 thereof.
The first and second dryer rollers 64a and 64b rotate while holding the sheet S therebetween. In the above configuration, the sheet S passes between the first and second dryer rollers 64a and 64b while receiving heat from the first and second dryer rollers 64a and 64b.
As described with reference to
Typically, the opposite edges U1, rather than the central part U2, of the sheet S tend to curl upon ink attachment. Therefore, heating the opposite edges U1 of the sheet S from the image formation side S1 thereof by the first dryer roller 64a can achieve effective heating of the opposite edges U1 of the sheet S and effective mitigation of sheet curling.
The following describes the inkjet recording apparatus 1 according to the second embodiment with reference to
As illustrated in
The storage 100 stores therein information indicating the specific first temperature T1 and information indicating the specific second temperature T2.
The control device 110 includes the receiver 111, a first calculator 115, a second calculator 116, the determination section 113, and a controller 118. Specifically, a processor executes computer programs stored in a storage device of the storage 100 to function as the receiver 111, the first and second calculators 115 and 116, the determination section 113, and the controller 118.
The first calculator 115 acquires image data from the receiver 111. The first calculator 115 calculates a first ink ejection amount based on the image data. Specifically, the first ink ejection amount refers to an amount of ink that the image forming device 30 is to eject toward first regions al of a trailing edge S3 of the sheet S, as illustrated in
The second calculator 116 acquires the image data from the receiver 111. The second calculator 116 calculates a second ink ejection amount based on the image data. The second ink ejection amount refers to an amount of ink that the image forming device 30 is to eject toward a second region α2 of the trailing edge S3 of the sheet S. The second region α2 refers to a region of the trailing edge S3 of the sheet S that occupies a central part thereof in the width direction thereof. The second region α2 represents for example a region liable to curl upon ink attachment. The size of the second region α2 is determined for example by an experiment. Information indicating the second region α2 is stored in the storage 100 in advance.
The determination section 113 determines whether or not to activate the first heat sources 64e based on the first ink ejection amount calculated by the first calculator 115. Activation of the first heat sources 64e means power supply to the first heat sources 64e by the first power source 64g to increase the temperature of the first heat sources 64e.
When the first ink ejection amount calculated by the first calculator 115 is larger than a specific first reference amount, the determination section 113 determines to activate the first heat sources 64e. By contrast, when the first ink ejection amount calculated by the first calculator 115 is equal to or smaller than the specific first reference amount, the determination section 113 determines not to activate the first heat sources 64e. Non-activation of the first heat sources 64e means no power supply by the first power source 64g to the first heat sources 64e. The specific first reference amount indicates a maximum value of the ink ejection amount in the first regions α1 in a condition in which the sheet S can be smoothly conveyed with occurrence of problems such as a sheet jam prevented. The specific first reference amount is determined for example by an experiment. Information indicating the specific first reference amount is stored in the storage 100 in advance.
The following describes an example of the specific first reference amount with reference to
The trailing edge S3 of the sheet S comes first in backside printing on the sheet S. When the specific first reference amount is set as in the above example, the first regions al of the sheet S can be prevented from coming into contact with the image forming device 30 in backside printing on the sheet S. Furthermore, unnecessary activation of the first heat sources 64e can be reduced. Thus, efficient activation of the first heat sources 64e can be achieved.
The determination section 113 also determines whether or not to activate the second heat source 64m based on the second ink ejection amount calculated by the second calculator 116.
When the second ejection amount calculated by the second calculator 116 is larger than a specific second reference amount, the determination section 113 determines to activate the second heat source 64m. By contrast, when the second ejection amount calculated by the second calculator 116 is equal to or smaller than the specific second reference amount, the determination section 113 determines not to activate the second heat source 64m. The specific second reference amount indicates for example a maximum value of the ink ejection amount in the second region α2 in a condition in which the sheet S can be smoothly conveyed with occurrence of problems such as a sheet jam prevented. The specific second reference amount is determined for example by an experiment. Information indicating the specific second reference amount is stored in the storage 100 in advance.
An example of the specific second reference amount is a maximum value of the ink ejection amount in the second region α2 when a curl in the second region α2 of the sheet S has a height smaller than the distance β2 between the image forming device 30 and the second conveyor device 40.
When the specific second reference amount is set as in the above example, the second region α2 of the sheet S can be prevented from coming into contact with the image forming device 30 in backside printing on the sheet S. Furthermore, unnecessary activation of the second heat source 64m can be reduced. Thus, efficient activation of the second heat source 64m can be achieved.
Description of the controller 118 will be continued with reference to
The controller 118 controls the first heat sources 64e, the second heat source 64m, and the image forming device 30 based on a determination result of the determination section 113.
The controller 118 is connected to the second decurler 64 to control the second decurler 64. Specifically, the controller 118 controls the first and second dryer rollers 64a and 64b, the first and second heaters 64c and 64j, and the second and third detection sections 64q and 64k.
The following describes operation of the control device 110 with reference to
At Step S210, the receiver 111 receives image data representing an image to be formed on a sheet S, as depicted in
The first calculator 115 acquires the image data from the receiver 111 at Step S220. The first calculator 115 calculates a first ink ejection amount of ink to be ejected toward the first regions al of the sheet S.
The second calculator 116 acquires the image data from the receiver 111 at Step S230. The second calculator 116 calculates a second ink ejection amount of ink to be ejected toward the second region α2 of the sheet S.
At Step S240, the determination section 113 determines whether or not to activate the first heat sources 64e and the second heat source 64m based on the first ink ejection amount calculated by the first calculator 115 and the second ink ejection amount calculated by the second calculator 116. That is, the determination section 113 determines prior to image formation on the sheet S whether or not to activate the first heat sources 64e and the second heat source 64m.
When the first ink ejection amount is larger than the specific first reference amount and the second ink ejection amount is larger than the specific second reference amount, the determination section 113 makes first determination. The first determination refers to determination to activate the first heat sources 64e and the second heat source 64m.
When the first ink ejection amount is larger than the specific first reference amount and the second ink ejection amount is equal to or smaller than the specific second reference amount, the determination section 113 makes second determination. The second determination refers to determination to activate the first heat sources 64e and not to activate the second heat source 64m.
When the first ink ejection amount is equal to or smaller than the specific first reference amount and the second ink ejection amount is larger than the specific second reference amount, the determination section 113 makes third determination. The third determination refers to determination to activate the second heat source 64m and not to activate the first heat sources 64e.
When the first ink ejection amount is equal to or smaller than the specific first reference amount and the second ink ejection amount is equal to or smaller than the specific second reference amount, the determination section 113 makes fourth determination. The fourth determination refers to determination not to activate the first heat sources 64e and the second heat source 64m.
When the determination section 113 makes the first determination, the routine proceeds to Step S250. When the determination section 113 makes the second determination, the routine proceeds to Step S310. When the determination section 113 makes the third determination, the routine proceeds to Step S370. When the determination section 113 makes the fourth determination, the routine proceeds to Step S430.
As depicted in
At Step S260, the second detection section 64q detects the temperature of the ends of the first dryer roller 64a. The third detection section 64k detects the temperature of the central part of the second dryer roller 64b.
At Step S270, the controller 118 receives information indicating the temperature of the ends of the first dryer roller 64a from the second detection section 64q. The controller 118 also receives information indicating the temperature of the central part of the second dryer roller 64b from the third detection section 64k. When the controller 118 determines that the temperature of the ends of the first dryer roller 64a is equal to or higher than the specific first temperature T1 and the temperature of the central part of the second dryer roller 64b is equal to or higher than the specific second temperature T2 (Yes at Step S270), the routine proceeds to Step S280. When the controller 118 determines that the temperature of the ends of the first dryer roller 64a is lower than the specific first temperature T1 and/or the temperature of the central part of the second dryer roller 64b is lower than the specific second temperature T2 (No at Step S270), the routine returns to Step S260.
At Step S280, the image forming device 30 forms an image on the sheet S. Specifically, the controller 118 first controls the first conveyor device 20 to convey the sheet S accommodated in the accommodation section 12 toward the image forming device 30. The controller 118 then controls the second conveyor device 40 to convey the sheet S under the image forming device 30. The controller 118 next controls the image forming device 30 to form the image on the sheet S. In response, the image forming device 30 ejects ink toward the sheet S to form the image on the sheet S.
At Step S290, the first decurler 63 conveys the sheet S. Specifically, the controller 118 first controls the third conveyor device 50 to convey the sheet S to the first decurler 63. In response, the first and second decurling rollers 63a and 63b of the first decurler 63 rotate while holding the sheet S therebetween to convey the sheet S. Thus, sheet curling is mitigated.
At Step S300, the second decurler 64 conveys the sheet S. Specifically, the controller 118 first controls the guide section 62 to guide the sheet S toward the second decurler 64. That is, the controller 118 causes the third diverging guide 68 to take the third guide posture. As a result, the third diverging guide 68 guides the sheet S to the second decurler 64. Then, the first and second dryer rollers 64a and 64b of the second decurler 64 rotate while holding the sheet S therebetween to convey the sheet S. As such, the first dryer roller 64a having the ends of which temperature is equal to or higher than the specific first temperature T1 comes into contact with the image formation side S1 of the sheet S. On the other hand, the second dryer roller 64b having the central part of which temperature is equal to or higher than the specific second temperature T2 comes into contact with the suction side S2 of the sheet S. As a result of contact, drying of ink attached to the opposite edges U1 and the central part U2 of the sheet S can be accelerated. Thus, effective mitigation of sheet curling at the opposite edges U1 and the central part U2 of the sheet S can be achieved.
The sheet S having passed through the second decurler 64 reaches the second guide passage 66.
At Step S310, the controller 118 activates the first heat sources 64e. The controller 118 does not activate the second heat source 64m.
At Step S320, the second detection section 64q detects the temperature of the first dryer roller 64a.
At Step S330, the controller 118 receives information indicating the temperature of the first dryer roller 64a from the second detection section 64q. When the controller 118 determines that the temperature of the first dryer roller 64a is equal to or higher than the specific first temperature T1 (Yes at Step S330), the routine proceeds to Step S340. When the controller 118 determines that the temperature of the first dryer roller 64a is lower than the specific first temperature T1 (No at Step S330), the routine returns to Step S320.
At Step S340, the image forming device 30 forms an image on the sheet S (see Step S280).
At Step S350, the first decurler 63 conveys the sheet S (see Step S290).
At Step S360, the second decurler 64 conveys the sheet S (see Step S300). The first dryer roller 64a having the ends of which temperature is equal to or higher than the specific first temperature T1 comes into contact with the image formation side S1 of the sheet S. As a result of contact, drying of ink attached to the opposite edges U1 of the sheet S can be accelerated, and effective mitigation of sheet curling at the opposite edges U1 of the sheet S can be achieved.
The sheet S having passed through the second decurler 64 reaches the second guide passage 66.
As depicted in
At Step S380, the third detection section 64k detects the temperature of the central part of the second dryer roller 64b.
At Step S390, the controller 118 receives information indicating the temperature of the second dryer roller 64b from the third detection section 64k. When the controller 118 determines that the temperature of the second dryer roller 64b is equal to or higher than the specific second temperature T2 (Yes at Step S390), the routine proceeds to Step S400. When the controller 118 determines that the temperature of the second dryer roller 64b is lower than the specific second temperature T2 (No at Step S390), the routine returns to Step S380.
At Step S400, the image forming device 30 forms an image on the sheet S (see Step S280).
At Step S410, the first decurler 63 conveys the sheet S (see Step S290).
At Step S420, the second decurler 64 conveys the sheet S (see Step S300). The second dryer roller 64b having the central part of which temperature is equal to or higher than the specific second temperature T2 comes into contact with the suction side S2 of the sheet S. As a result of contact, drying of ink attached to the central part U2 of the sheet S can be accelerated. Thus, effective mitigation of sheet curling at the central part U2 of the sheet S can be achieved.
The sheet S having passed through the second decurler 64 reaches the second guide passage 66.
At Step S430, the image forming device 30 forms an image on the sheet S (see Step S280). Thus, the image is formed on the sheet S in a state in which the first heat sources 64e and the second heat source 64m are not activated.
At Step S440, the first decurler 63 conveys the sheet S (see Step S290).
At Step S450, the controller 118 controls the guide section 62 to guide the sheet S to the third guide passage 67. That is, the controller 118 causes the third diverging guide 68 to take the fourth guide posture. As a result, the sheet S is conveyed to the third guide passage 67 and the second guide passage 66 in the stated order not via the second decurler 64.
Alternatively, after reaching the second guide passage 66 at any of Steps S300, S360, S420, and S450, the sheet S may be conveyed to the ejection passage 71 and ejected onto the exit tray 11. Or, the sheet S having reached the second guide passage 66 may be conveyed to the paper reversing passage 81 and the paper returning passage 82 in the stated order for backside printing on the sheet S.
As described above with reference to
As depicted at Step S440, a to-be-heated region of the sheet S can be selected from among a plurality of regions of the sheet S. The plurality of regions are the opposite edges U1 and the central part U2 in the present embodiment. In the above configuration, a to-be-heated region of the sheet S can be selected in correspondence with a region of the sheet S to which ink is attached. Consequently, running cost of the apparatus can be effectively reduced.
By not unnecessarily activating the first heat sources 64e and the second heat source 64m, the number of times that members of the second decurler 64, such as the first and second dryer rollers 64a and 64b are heated by heat of the first heat sources 64e and the second heat source 64m can be reduced. As a result, the lifetime of the second decurler 64 can be extended.
Furthermore, in a situation in which the sheet S need not be heated, the sheet S can be conveyed not via the second decurler 64 as depicted at Step S450. As a result, the number of times that the second decurler 64 is activated can be reduced and the lifetime of the second decurler 64 can be extended.
The following describes variations of the second decurler 64 with reference to
As illustrated in
The number of the support rollers 64h is two in the third variation. The support rollers 64h are supported in a rotatable manner. The support rollers 64h are spaced from each other. The dryer belt 64i is an endless belt. The dryer belt 64i is wound between the support rollers 64h. The dryer belt 64i is supported in a rotatable manner. Specifically, the dryer belt 64i is supported by the support rollers 64h in a rotatable manner. The dryer belt 64i is rotated by rotation of the support rollers 64h while in contact with the support rollers 64h.
The first dryer roller 64a and the dryer belt 64i rotate while holding the sheet S therebetween to convey the sheet S. Specifically, the first dryer roller 64a and the dryer belt 64i rotate while holding the sheet S between the outer circumferential surface of the first dryer roller 64a and the outer surface of the dryer belt 64i. The outer surface of the dryer belt 64i refers to one of surfaces of the dryer belt 64i that is opposite to the other surface thereof in contact with the support rollers 64h.
The first dryer roller 64a holds the sheet S in cooperation with the dryer belt 64i between the first dryer roller 64a and a specific portion R of the dryer belt 64i. The specific portion R refers to a portion of the dryer belt 64i located at a position corresponding to the first dryer roller 64a that is not opposite to the support rollers 64h with the dryer belt 64i therebetween. In other words, the specific portion R is a portion of the dryer belt 64i that is out of contact with the support rollers 64h. In the above configuration, the first dryer roller 64a and the dryer belt 64i rotate while holding the sheet S between the first dryer roller 64a and the specific portion R of the dryer belt 64i to convey the sheet S.
The specific portion R of the dryer belt 64i receives pressure from the first dryer roller 64a to warp. As such, the first dryer roller 64a holds the sheet S in cooperation with the dryer belt 64i between the first dryer roller 64a and a warped portion of the dryer belt 64i.
The second dryer roller 64b is in contact with the dryer belt 64i. Specifically, the second dryer roller 64b is in contact with the outer surface of the dryer belt 64i. The second dryer roller 64b rotates while in contact with the dryer belt 64i. Specifically, the second dryer roller 64b in contact with the dryer belt 64i rotates together with the dryer belt 64i.
Heat of the second heat source 64m is transferred to the sheet S via the second dryer roller 64b and the dryer belt 64i. That is, the second heat source 64m heats the dryer belt 64i to heat the central part U2 of the sheet S through the dryer belt 64i.
As illustrated in
The support rollers 64h are spaced from one another. The support rollers 64h are not aligned. The number of the support rollers 64h is three in the fourth variation. In the fourth variation, two of the three support rollers 64h are disposed on the conveyance path of the sheet S while the other of the support rollers 64h is spaced apart from the conveyance path of the sheet S. The first dryer roller 64a and the dryer belt 64i rotate while holding the sheet S between the first dryer roller 64a and the specific portion R of the dryer belt 64i to convey the sheet S. That is, the first dryer roller 64a holds the sheet S in cooperation with the dryer belt 64i between the first dryer roller 64a and a warped portion of the dryer belt 64i.
The second dryer roller 64b is in contact with the outer surface of the dryer belt 64i. The second dryer roller 64b in contact with the dryer belt 64i rotates together with the dryer belt 64i.
Heat of the second heat source 64m is transferred to the sheet S through the second dryer roller 64b and the dryer belt 64i. That is, the second heat source 64m heats the dryer belt 64i to heat the central part U2 of the sheet S through the dryer belt 64i.
As described above with reference to
When the first dryer roller 64a and the dryer belt 64i hold the sheet S therebetween, the first dryer roller 64a is located opposite to the image formation side S1 of the sheet S. Also, when the first dryer roller 64a and the dryer belt 64i hold the sheet S therebetween, the dryer belt 64i faces the suction side S2 of the sheet S. In the above configuration, the sheet S warps in a direction opposite to a curling direction while being conveyed through rotation of the first dryer roller 64a and the dryer belt 64i holding the sheet S therebetween. The curling direction refers to a direction in which the sheet S curls. Consequently, effective mitigation of sheet curling can be achieved.
Embodiments of the present disclosure have been described so far with reference to the accompanying drawings (
(1) In the following description, the second decurler 64, the second decurler 641, the second decurler 642, the third decurler 643, and the fourth decurler 644 are referred to generally as a second decurling member. The second decurling member is disposed downstream of the first decurler 63 in terms of the sheet conveyance direction X in the first and second embodiments. However, the second decurling member may be disposed upstream of the first decurler 63 in terms of the sheet conveyance direction X. In the above configuration, the second decurling member heats the sheet S prior to conveyance of the sheet S to the first decurler 63 to accelerate drying of ink on the sheet S. As a result, attachment of ink on the sheet S to rollers (i.e., first and second decurling rollers 63a and 63b) of the first decurler 63 can be effectively inhibited.
(2) The second decurling member is disposed between the image forming device 30 and the ejection passage 71 in the first and second embodiments. However, it is only required that the second decurling member is disposed downstream of the image forming device 30 in terms of the sheet conveyance direction X. The second decurling member may be for example disposed at the paper returning passage 82. In the above configuration, the second decurling member accelerates drying of ink on the sheet S in the paper returning passage 82 to mitigate curling of the sheet S. As a result, a situation in which the sheet S is rubbed against the image forming device 30 in backside printing on the sheet S can be prevented to achieve smooth backside printing on the sheet S.
(3) A third heat source different from the first heat source 64e may be provided at the second dryer roller 64b of the second decurler 64 in the first embodiment. In the above configuration, the third heat source heats the second dryer roller 64b. As a result, the first and second dryer rollers 64a and 64b heat the sheet S, thereby achieving effective sheet heating.
Furthermore, it is possible that in each of the second decurler 641 and the second decurler 642, an additional roller in contact with the dryer belt 64i is provided and a second heat source different from the first heat source 64e is provided at the additional roller. The additional roller rotates while in contact with the dryer belt 64i. In the above configuration, the second heat source heats the dryer belt 64i through the additional roller. As a result, the first dryer roller 64a and the dryer belt 64i heat the sheet S, thereby achieving effective sheet heating.
In a configuration in which the second heat source is provided in the second decurling member, the controller 114 or 118 activates the second heat source in synchronization with timing of activation of the first heat source 64e.
(4) The decurling device 61 includes the first and second decurlers 63 and 64 in the first and second embodiments. However, the decurling device 61 may include only the second decurler 64. That is, the decurling device 61 not including the first decurler 63 mitigates sheet curling using only the second decurler 64. In the above configuration, the number of components of the device can be reduced.
(5) In the second decurler 64 in the first embodiment, when the first and second dryer rollers 64a and 64b hold the sheet S therebetween, the first dryer roller 64a is located opposite to the image formation side S1 of the sheet S while the second dryer roller 64b is located opposite to the suction side S2 of the sheet S. However, it is possible that the first dryer roller 64a is located opposite to the suction side S2 of the sheet S while the second dryer roller 64b is located opposite to the image formation side S1 of the sheet S. That is, the first dryer roller 64a heats the sheet S from the suction side S2 to dry ink attached to the image formation side S1 of the sheet S. However, the first dryer roller 64a can directly heat the image formation side S1 of the sheet S to effectively accelerate drying of ink attached to the image formation side S1 of the sheet S in a configuration in which the first dryer roller 64a is located opposite to the image formation side 51 of the sheet S, as described in the first embodiment.
(6) The first decurler 63 holds the sheet S between the paired rollers (i.e., the first and second decurling rollers 63a and 63b) in the first and second embodiments. However, the first decurler 63 may hold the sheet S between the first decurling roller 63a and a decurling belt. That is, the first decurler 63 holds the sheet S in the same manner as that adopted in the second decurler 641 or 642 in the first embodiment (see
In a configuration in which the first decurler 63 includes the first decurling roller 63a and the decurling belt, the sheet S curls in a direction opposite to the curling direction while being conveyed through rotation of the first decurling roller 63a and the decurling belt holding the sheet S therebetween. Consequently, effective mitigation of sheet curling can be achieved.
(7) The decurling device 61 in the first and second embodiments may be provided in a post-printing processing device. The post-printing processing device is connected to the inkjet recording apparatus 1. The post-printing processing device performs specific post-printing processing on a sheet S. Examples of the specific post-printing processing include punching and stapling. Punching is processing to perforate a sheet S. Stapling is processing by which a stack of sheets S is bound with a binding piece such as a staple.
(8) A sheet S with an ink image formed thereon is conveyed to the decurling device 61 in the first and second embodiments. The ink image refers to an image formed with ink. However, a sheet S with a liquid different from such ink applied thereon may be conveyed to the decurling device 61. The decurling device 61 mitigates curling of a sheet S wetted with the liquid.
(9) In the second decurling member in the second embodiment, the first heat sources 64e are provided at the first dryer roller 64a and the second heat source 64m is provided at the second dryer roller 64b. However, it is possible that the second heat source 64m is provided at the first dryer roller 64a and the first heat sources 64e are provided at the second dryer roller 64b. That is, the first dryer roller 64a heats the central part U2 of the sheet S while the second dryer roller 64b heats the opposite edges U1 of the sheet S. Layout flexibility for the first heat sources 64e and the second heat source 64m can be accordingly increased.
(10) Both of the first decurler 63 and the second decurling member are disposed in the interior of the casing 10 of the inkjet recording apparatus 1 in the first and second embodiments. However, either or both of the first decurler 63 and the second decurling member may serve as a post-printing processing device. In the above configuration, either or both of the first decurler 63 and the second decurling member are provided in the exterior of the casing 10 and connected to the ejection device 70. In the above configuration, the sheet S ejected from the ejection device 70 is conveyed to either or both of the first decurler 63 and the second decurling member. As a result, either or both of the first decurler 63 and the second decurling member mitigate curling of the sheet S ejected from the ejection device 70.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2017-104352 | May 2017 | JP | national |
| 2017-104353 | May 2017 | JP | national |
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| 2003-291332 | Oct 2003 | JP |
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| Number | Date | Country | |
|---|---|---|---|
| 20180339528 A1 | Nov 2018 | US |
