JP2022116308A - Post-processing device, method of controlling post-processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a post-processing device that suppresses the deformation of a medium in a stacker and enables smooth post-processing.

SOLUTION: The post-processing device includes: a stacker where a medium is temporarily loaded; a post-processing part that performs post-processing on the medium loaded on the stacker; a paper discharge tray where the medium to be discharged is stacked; and a suppressing part that suppresses the deformation of the medium in the condition where it is loaded on the stacker.

SELECTED DRAWING: Figure 12

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a post-processing device and a control method for the post-processing device.

2. Description of the Related Art Conventionally, there has been known a post-processing apparatus including a placed sheet processing section that performs post-processing such as stapling and shift processing on sheets on which images have been formed (see, for example, Japanese Laid-Open Patent Publication No. 2002-100001). In the post-processing device, post-processing is performed while a plurality of sheets having images formed thereon are placed on a processing tray.
As an apparatus for forming an image on paper, for example, an inkjet printer having a recording head that ejects liquid ink in the form of droplets is known.

JP 2015-107840 A

By the way, when an image is formed using an inkjet printer, the paper on which the image is formed may curl (a state in which a portion of the paper is bent or deformed) due to absorption of ink (moisture) or drying of the ink. There is
For this reason, when sheets on which an image has been formed by an inkjet printer are sequentially placed on the processing tray of the post-processing device, if the degree of curling of the first placed sheet increases, the sheet conveyed later may However, there is a problem that the curled portion of the paper placed earlier causes the paper to be unevenly arranged or causes a problem in transportation.

DISCLOSURE OF THE INVENTION The present invention has been made to solve the problem of unevenness of media and transportation problems, and can be implemented as the following forms or application examples.

[Application Example 1] A post-processing apparatus according to this application example includes a stacker on which media are temporarily placed, and a post-processing section that performs post-processing on the media placed on the stacker. a discharge tray for stacking the discharged medium; and a suppression unit for suppressing deformation of the medium placed on the stacker.

According to this configuration, for example, a medium on which an image or the like is formed can be placed on the stacker, and post-processing can be performed on the medium placed on the stacker by using the post-processing section.
Here, as a method of forming an image on a medium such as paper, for example, an inkjet printer that ejects liquid ink as droplets may be used.
However, a medium on which an image is formed by an inkjet printer may curl due to the absorption of ink (moisture), drying of the ink, or the form of image formation (for example, single-sided or double-sided printing). . For this reason, when a medium on which an image is formed by an inkjet printer is placed on a stacker, the placed medium curls, and a part of another medium is caught in the curled portion, resulting in unevenness of the medium, There is a risk of causing a transport failure or the like.
Therefore, according to the above configuration, deformation such as curling of the media placed on the stacker is suppressed by the suppressing section. As a result, it is possible to reduce the occurrence of media irregularities, transport failures, and the like.

APPLICATION EXAMPLE 2 In the post-processing apparatus according to the application example described above, when a jam occurs upstream of the stacker in the transport path of the medium, the suppressing unit suppresses deformation of the medium. do.

If a jam in which the medium is clogged in the transport path occurs on the upstream side of the transport path of the medium from the stacker, the transport of the medium is stopped to clear the jam. However, until the jam is cleared and the media is transported again, the media already placed on the stacker will be deformed (curled) to a large extent. When the medium is conveyed to the stacker, the curled portion of the medium already placed on the stacker may catch part of another medium.
Therefore, according to the above configuration, when a jam occurs, the suppressing section suppresses the deformation of the media placed on the stacker. As a result, the curling of the medium can be suppressed, and it is possible to reduce medium conveyance failures and the like.

Application Example 3 The post-processing apparatus according to the application example is characterized in that the suppression unit suppresses between the stacker and the discharge tray.

According to this configuration, the suppressing section exerts a curl suppressing function on the medium between the stacker and the discharge tray. That is, the suppression unit suppresses curling of the media outside the stacker. Therefore, the suppression unit can independently suppress the curling of the medium without being involved in the stacker.

Application Example 4 The suppression unit of the post-processing device according to the above application example includes a first roller and a second roller, and the first roller and the second roller are spaced apart in a direction in which the medium is sandwiched between the first roller and the second roller. is variable between a first interval and a second interval that is narrower than the first interval. The space between the first roller and the second roller is variable to the second space through the medium placed on the stacker.

If a jam in which the medium is clogged in the transport path occurs on the upstream side of the transport path of the medium from the stacker, the transport of the medium is stopped to clear the jam. However, until the jam is cleared and the media is transported again, the media already placed on the stacker will be deformed (curled) to a large extent. When the medium is conveyed to the stacker, the curled portion of the medium already placed on the stacker may catch part of another medium.
Therefore, in the above configuration, when a jam occurs, the gap between the first roller and the second roller is varied from the first gap to the second gap via the media placed on the stacker. That is, the gap between the first roller and the second roller is narrowed. Thereby, the curling of the media left in the stacker is easily regulated by the first roller and the second roller. Therefore, curling is suppressed, and it is possible to reduce medium conveyance failures and the like.

Application Example 5 In the post-processing device according to the application example described above, at the first interval, either one of the first roller and the second roller does not contact the medium, A two-spacing is characterized by a first roller and a second roller contacting the media.

According to this configuration, by changing the distance from the first distance to the second distance, the medium is sandwiched between the first roller and the second roller, so curling of the medium can be reliably suppressed.

Application Example 6 The post-processing apparatus according to the above application example is characterized in that the suppression unit suppresses on the stacker.

According to this configuration, the suppressing section exerts a curl suppressing function on the media on the stacker. That is, the suppressing section can suppress the curling of the medium while being involved with a part of the stacker.

Application Example 7 In the post-processing device according to the above application example, the suppressing section includes a contact section capable of coming into contact with the surface of the medium, and the distance between the medium placed on the stacker and the contact section is is variable between a first interval and a second interval that is narrower than the first interval. The distance between the medium placed on the stacker and the contact portion is variable to the second distance.

According to this configuration, when a jam occurs in which the medium is jammed in the transport path upstream of the stacker in the transport path, the distance between the medium placed on the stacker and the contact portion is reduced from the first distance. Variable to the second interval. That is, the distance between the medium and the contact portion is narrowed. Therefore, the curling of the media left in the stacker is easily regulated by the contact portion. Therefore, curling is suppressed, and medium conveyance failures can be reduced.

Application Example 8 In the post-processing device according to the above application example, the contact portion does not contact the medium at the first distance, and the contact portion does not contact the medium at the second distance. characterized by contact.

According to this configuration, by changing the distance from the first distance to the second distance, the medium is brought into contact with the contact portion, and deformation of the medium is further restricted. Therefore, curling of the medium can be reliably suppressed.

APPLICATION EXAMPLE 9 In the post-processing apparatus according to the above application example, the suppression unit is an air blower, and when a jam occurs upstream of the stacker in the transport path of the medium, the paper is placed on the stacker. It is characterized by blowing air against the medium in the state.

According to this configuration, it is possible to easily suppress deformation such as curling of the medium due to air pressure caused by air blowing.

[Application Example 10] In the post-processing apparatus according to the above application example, the suppression unit includes a humidification unit capable of humidifying the medium placed on the stacker, and the medium is conveyed rather than the stacker. It is characterized in that when the jam occurs on the upstream side of the path, the medium placed on the stacker is humidified.

According to this configuration, when a jam occurs, deformation of the medium is suppressed while humidifying the medium. This makes it possible to more effectively suppress curling of the medium.

APPLICATION EXAMPLE 11 In the post-processing device according to the above application example, when the jam occurs on the upstream side of the transport path of the media relative to the stacker, the post-processing apparatus can The suppressing unit is driven after the medium on the side is conveyed to the stacker.

According to this configuration, when a state (jam) in which the medium is jammed in the transport path occurs on the upstream side of the transport path of the medium from the stacker, there is a normal flow between the stacker and the location where the jam occurred. The medium is transported to the stacker, and then the suppressor is driven. As a result, normal media (medium that is not jammed) are not discarded, and waste can be reduced.

APPLICATION EXAMPLE 12 In the post-processing device according to the application example described above, when the jam is cleared, the detection result of the detection unit arranged in the conveying path upstream of the suppression unit and at a position closest to the suppression unit Based on, the driving of the suppressing unit is canceled.

When the jam is cleared, the drive of the suppressing unit is released and the medium transport is restarted, but the time until the first medium transported after the jam is cleared is placed on the stacker is relatively long. In that case, the deformation of the media already placed on the stacker before the jam occurs becomes large. On the other hand, it is also necessary to consider the time required for the media stacker to be reliably transported after the suppression unit is driven. Therefore, when the jam is resolved, the timing of releasing the driving of the suppression unit becomes a problem.
Therefore, according to the above configuration, it is detected that the media transported after the jam is resolved can be placed on the stacker, and furthermore, the detection result of the detection unit disposed closest to the upstream of the transport path of the suppressing unit Based on this, the driving of the suppression unit is released. That is, after the jam is cleared, the suppression unit can be driven using the maximum amount of time until the media are placed on the stacker. Therefore, it is possible to suppress the deformation of the medium after the jam is cleared.

Application Example 13 A printing apparatus according to this application example includes an image forming apparatus that forms an image on a medium, a stacker that temporarily places the medium on which the image is formed, and a stacker that places the medium on which the image is formed. a post-processing unit configured to perform post-processing on the media in a stacked state; and a suppressing unit configured to suppress deformation of the media in the state of being placed on the stacker. and a device.

According to this configuration, when the medium on which the image is formed by the image forming apparatus is placed on the stacker, the suppressing section suppresses deformation such as curling of the medium. As a result, it is possible to reduce the occurrence of non-uniformity of the medium, transportation failure, and the like.

Application Example 14 A printing apparatus according to this application example includes an image forming apparatus that forms an image on a medium, a stacker that temporarily places the medium on which the image is formed, and a stacker that places the medium on which the image is formed. a post-processing unit configured to perform post-processing on the media in a stacked state; and a suppressing unit configured to suppress deformation of the media in the state of being placed on the stacker. and an intermediate conveying device that conveys the medium on which the image has been formed by the image forming device to the post-processing device.

According to this configuration, the medium on which the image is formed by the image forming apparatus is transported to the post-processing device via the intermediate transport device. Then, when the medium on which the image is formed is placed on the stacker, the suppression unit suppresses deformation such as curling of the medium. As a result, it is possible to reduce the occurrence of non-uniformity of the medium, transportation failure, and the like.

1 is a schematic diagram showing the configuration of a printing apparatus; FIG. FIG. 2 is a configuration diagram showing the configuration of an image forming apparatus; FIG. 2 is a configuration diagram showing the configuration of an intermediate conveying device; 4A and 4B are schematic diagrams showing the operation of the post-processing device; 4A and 4B are schematic diagrams showing the operation of the post-processing device; 4A and 4B are schematic diagrams showing an operation method of the printing apparatus; 4A and 4B are schematic diagrams showing an operation method of the printing apparatus; 4A and 4B are schematic diagrams showing an operation method of the printing apparatus; 4A and 4B are schematic diagrams showing an operation method of the printing apparatus; Schematic which shows the structure of a suppression part. Schematic which shows the structure of a suppression part. Schematic which shows the structure of a suppression part. FIG. 2 is a block diagram showing a partial configuration of a control unit of the printing apparatus; 4 is a flowchart showing a control method of the printing device; 4 is a flow chart showing an execution processing method of a suppression unit; 4 is a flowchart showing a method of canceling the suppression unit;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following figures, the scale of each member and the like is changed from the actual scale in order to make the size of each member and the like recognizable.

First, the configuration of the printing apparatus will be described. FIG. 1 is a schematic diagram showing the configuration of a printing apparatus, FIG. 2 is a configuration diagram showing the configuration of an image forming apparatus, and FIG. 3 is a configuration diagram showing the configuration of an intermediate conveying device. As shown in FIG. 1, the printing apparatus 1 according to this embodiment includes an image forming apparatus 100, an intermediate conveying apparatus 200, and a post-processing apparatus 300. As shown in FIG. It also has a control unit 10 (see FIG. 13) that controls driving of each mechanism in the printing apparatus 1 in an integrated manner. The image forming apparatus 100 is, for example, an apparatus that forms an image on a sheet of paper M as a medium. The post-processing device 300 is, for example, a device that performs post-processing such as stapler processing for binding a plurality of sheets of paper M on which images have been formed. The intermediate conveying device 200 is a device that conveys the sheet M on which an image has been formed by the image forming device 100 to the post-processing device 300 . The intermediate conveying device 200 is arranged between the image forming device 100 and the post-processing device 300 .

In the printing apparatus 1 of the present embodiment, the third discharge path 153 as the upstream transport path of the image forming apparatus 100 is connected to the intermediate transport path 218 of the intermediate transport apparatus 200, and the intermediate transport path 218 is connected to the post-processing apparatus 300. It is connected to the downstream transport path 319 . Then, by the third discharge path 153 , the intermediate transport path 218 , and the downstream transport path 319 , from the image forming apparatus 100 on the upstream side in the transport direction of the sheet M to the post-processing apparatus via the intermediate transport apparatus 200 . 300 (a chain double-dashed line in FIG. 1).

As shown in FIG. 1, the image forming apparatus 100 is an inkjet printer that records images such as characters, figures, and photographs by attaching ink, which is an example of a liquid, to paper M, which is an example of a medium. It has a recording-apparatus-side housing 101 having a shape. An operation unit 102 for performing various operations of the image forming apparatus 100 is attached to the upper portion of the recording apparatus side housing 101 .

The image forming apparatus 100 is provided with a paper cassette 103 extending from the center to the bottom of the image forming apparatus 100 in the vertical direction Z. As shown in FIG. In this embodiment, four paper cassettes 103 are arranged side by side in the vertical direction Z. As shown in FIG. Each paper cassette 103 accommodates sheets of paper M on which recording is to be performed by the image forming apparatus 100 in a stacked state. Further, each paper cassette 103 is formed with a grip portion 103a that can be gripped by the user. The paper cassette 103 is configured to be detachable from the housing 101 on the recording apparatus side. Note that the sheets M accommodated in the respective sheet cassettes 103 may be of different types, or may be of the same type.

A rectangular front plate cover 104 is provided above the uppermost paper cassette 103 in the vertical direction Z. As shown in FIG. The front plate cover 104 is rotatably provided with a long side adjacent to the paper cassette 103 as a base end. It is configured to be rotatable between two positions, a closed position forming part of the body 101 .

Further, as shown in FIG. 2, a discharge port 108 through which the paper M is discharged is formed in a part of the recording device housing 101 on the intermediate conveying device 200 side. Further, below the discharge port 108, a paper discharge tray 109 extending from the recording device side housing 101 toward the intermediate conveying device 200 is provided so as to be attachable as required. That is, the paper M ejected through the ejection port 108 is placed on the paper ejection tray 109 . Note that the discharge tray 109 is detachable from the recording apparatus housing 101, and has a base end connected to the recording apparatus housing 101 toward a tip opposite to the base end. It has an upward slope (rising to the left in FIG. 2).

As shown in FIG. 2, in the recording apparatus housing 101 of the image forming apparatus 100, there are a recording unit 110 for recording the paper M from above in the vertical direction Z, and an intra-apparatus transport path 120 for the paper M. A conveying unit 130 for conveying along is provided. The intra-apparatus transport path 120 is formed such that when the width direction of the paper M is the direction along the front-rear direction Y, the paper M is transported with the direction intersecting the width direction as the transport direction.

The recording unit 110 includes a line-head type recording head 111 capable of simultaneously ejecting ink across substantially the entire width of the paper M. As shown in FIG. The recording unit 110 forms an image on the paper M by applying ink ejected from the recording head 111 to a recording surface (a surface on which an image is printed) of the paper M facing the recording head 111 .

The transport unit 130 is arranged along the intra-apparatus transport path 120 and has a plurality of transport roller pairs 131 driven by a transport drive motor (not shown) and a belt transport unit 132 provided immediately below the recording unit 110 . is doing. That is, ink is ejected from the recording head 111 onto the paper M being conveyed by the belt conveying unit 132, and recording is performed.

The belt conveying unit 132 includes a drive roller 133 arranged upstream of the recording head 111 in the conveying direction, a driven roller 134 arranged downstream of the recording head 111 in the conveying direction, these rollers 133, 134 and an endless annular belt 135 . As the drive roller 133 is driven to rotate, the belt 135 rotates, and the sheet M is conveyed downstream by the belt 135 that rotates. That is, the outer peripheral surface of the belt 135 functions as a support surface that supports the paper M on which recording is performed.

The intra-apparatus transport path 120 branches into a supply path 140 through which the paper M is transported toward the recording unit 110, a discharge path 150 through which the paper M on which recording has been performed by the recording unit 110 and which has been recorded is transported. and a branch path 160 that branches at a mechanism 147 .

The supply route 140 has a first supply route 141 , a second supply route 142 and a third supply route 143 . In the first supply path 141 , a sheet M inserted from an insertion opening 141 b exposed by opening a cover 141 a provided on the right side surface of the recording apparatus housing 101 is conveyed to the recording section 110 . That is, the sheet M inserted from the insertion port 141b is linearly transported toward the recording section 110 by the rotational driving of the first drive roller pair 144. As shown in FIG.

In the second supply path 142, in the vertical direction Z, the paper sheets M contained in the paper cassettes 103 provided in the lower part of the recording apparatus side housing 101 are conveyed to the recording section 110. FIG. That is, of the paper sheets M stored in the paper cassette 103 in a stacked state, the uppermost paper sheet M is sent out by the pickup roller 142a and separated sheet by sheet by the pair of separation rollers 145, after which the posture in the vertical direction Z is reversed. While being rotated, the second drive roller pair 146 is driven to rotate and conveyed toward the recording unit 110 .

In the third supply path 143 , when performing double-sided printing in which images are recorded on both sides of the paper M, the paper M whose one side has been recorded by the recording unit 110 is conveyed to the recording unit 110 again. That is, a branch path 160 branching from the ejection path 150 is provided downstream of the recording unit 110 in the transport direction. That is, when double-sided printing is performed, the paper M is conveyed to the branch path 160 by the operation of the branch mechanism 147 provided in the middle of the ejection path 150 . In addition, a pair of branch path rollers 161 capable of rotating in both forward and reverse directions is provided downstream of the branch mechanism 147 in the branch path 160 .

In double-sided printing, the paper M printed on one side is once guided to the branch path 160 by the branch mechanism 147 and conveyed downstream in the branch path 160 by the pair of branch path rollers 161 rotating normally. After that, the sheet M conveyed to the branch path 160 is reversely conveyed in the branch path 160 from the downstream side to the upstream side by the branch path roller pair 161 that reverses. That is, the conveying direction of the sheet M conveyed along the branch path 160 is reversed.

The paper M reversely conveyed from the branch path 160 is conveyed to the third supply path 143 and conveyed toward the recording section 110 by the plurality of conveying roller pairs 131 . By being conveyed through the third supply path 143 , the paper M is reversed so that the other side that is not printed faces the recording section 110 , and is conveyed toward the recording section 110 by rotational driving of the third drive roller pair 148 . be done. In other words, the third supply path 143 functions as a reversing transport path that transports the sheet M while reversing the orientation of the sheet M in the vertical direction Z. As shown in FIG.

Of the supply paths 141 , 142 , and 143 , the second supply path 142 and the third supply path 143 transport the paper M toward the recording unit 110 while the posture of the paper M is curved in the vertical direction Z. On the other hand, in the first supply path 141, the paper M is conveyed toward the recording unit 110 without the posture of the paper M being greatly curved compared to the second supply path 142 and the third supply path 143. .

The paper M conveyed through each of the supply paths 141, 142, and 143 is conveyed to the alignment roller pair 149 arranged on the upstream side in the transportation direction of the recording unit 110, and then to the alignment roller pair 149 whose rotation has stopped. Its tip hits. The inclination of the sheet M with respect to the conveying direction is corrected (skewed) by the state in which the sheet M collides against the pair of alignment rollers 149 . Then, the skew-corrected sheet M is transported to the recording unit 110 in an aligned state by the subsequent rotational driving of the alignment roller pair 149 .

The recording unit 110 performs recording on one side or both sides of the sheet M, and the recording sheet M is transported by the transport roller pair 131 along the discharge path 150 forming the downstream part of the intra-apparatus transport path 120 . The discharge route 150 branches into a first discharge route 151 , a second discharge route 152 , and a third discharge route 153 at positions downstream of the branching route 160 . That is, after the sheet M on which recording has been completed is conveyed through a common discharge route (upstream discharge route) 154 constituting the upstream portion of the discharge route 150, a guide mechanism (switching mechanism) provided at the downstream end of the common discharge route 154 Guide portion 180 guides to one of first to third discharge paths 151 , 152 , and 153 constituting the downstream portion of discharge path 150 .

A first ejection path (upper ejection path) 151 is provided so as to curve upward along the branch path 160 and extend upward from the recording apparatus side housing 101 . The paper M conveyed through the first discharge path 151 is discharged from a discharge port 155 that opens in a part of the recording apparatus side housing 101 so as to be the terminal end of the first discharge path 151 . Then, the paper M discharged from the discharge port 155 falls downward in the vertical direction Z, and is discharged onto the mounting table 156 in a stacked state as indicated by the two-dot chain line in FIG. The sheet M is discharged from the discharge port 155 onto the mounting table 156 by the transport roller pairs 131 arranged at a plurality of positions on the discharge path 150 in such a manner that the recording surface faces downward in the vertical direction Z during single-sided printing. be.

The mounting table 156 has an inclined shape rising upward in the vertical direction Z as it goes rightward in the left-right direction X, and the sheets M are mounted on this mounting table 156 in a stacked state. At this time, each sheet M placed on the mounting table 156 moves to the left along the inclination of the mounting table 156, and moves toward the vertical side wall 157 provided below the discharge port 155 of the recording apparatus side housing 101. is placed close to the

The first ejection path 151 also has a curved reversing path 151 a for reversing the front and back of the paper M recorded by the recording unit 110 while the paper M is conveyed to the ejection port 155 . That is, the curved reversal path 151a is curved with the recording surface of the sheet M recorded by the recording unit 110 facing inward, and the state in which the recording surface of the sheet M faces upward in the vertical direction Z to the vertical direction Z. The sheet M is turned over so that it faces downward. Accordingly, in the ejection path 150, the sheet M is ejected from the ejection port 155 in a state in which the recording surface faces the mounting table 156 during single-sided printing by passing through the curved reversal path 151a.

The second ejection path 152 branches downward in the vertical direction Z from the first ejection path 151 and extends linearly (horizontally) from the recording unit 110 toward the intermediate conveying device 200 . Therefore, the sheet M conveyed through the second ejection path 152 is not conveyed in a curved posture as in the first ejection path 151, but is kept in the same posture as when it passed through the recording unit 110. It is conveyed linearly and discharged from the discharge port 108 toward the paper discharge tray 109 . That is, the second ejection path 152 functions as a non-reversing ejection path that conveys the sheet M toward the ejection tray 109 without reversing the orientation of the sheet M. FIG.

The third discharge path 153 branches downward in the vertical direction Z from the second discharge path 152 and extends obliquely downward in the vertical direction Z so as to go downward from the recording apparatus housing 101 . The downstream end thereof is connected to the intermediate conveying path 218 of the intermediate conveying device 200 . That is, the paper M conveyed through the third discharge path 153 is discharged to the intermediate conveying device 200 . A transport detection unit 199 capable of detecting the presence or absence of the paper M is provided in the third discharge path 153 . The transport detection unit 199 is, for example, a light transmission type or light reflection type photointerrupter, and includes a light emitting unit that emits light and a light receiving unit that receives the light emitted from the light emitting unit. As the light emitting element of the light emitting section, for example, an LED (Light Emitting Diode) light emitting element, a laser light emitting element, or the like is applied. Also, the light-receiving portion is configured by a phototransistor, a photo IC, or the like. The presence or absence of the sheet M (ON/OFF of light reception in the light receiving section) can be detected by the light emitting section and the light receiving section.

The transport detection unit 199 is connected to the control unit 10 (see FIG. 13) and driven and controlled based on a predetermined program. The control unit 10 drives the transport detection unit 199 to detect the presence or absence of the paper M by comparing the amount of light received by the light receiving unit with a predetermined threshold value. When the presence and absence of the paper M are repeatedly detected in synchronization with the driving of the transport roller pair 131, it is determined that the paper M is transported normally. On the other hand, if the amount of light received by the light-receiving unit remains unchanged at a predetermined timing or within a predetermined period of time, it is determined that there is an abnormal state (jam). For example, when the paper M is not normally conveyed from the recording head 111 side due to the occurrence of a paper M conveyance failure, it is determined that an abnormal state (jam) has occurred.

A part of the ejection path 150 and a part of the branch path 160 are attached to a drawer unit 170 provided in the recording apparatus side housing 101 . It should be noted that the drawer unit 170 is configured to be detachable from the recording apparatus housing 101 .

Here, the paper M that can be applied to the printing apparatus 1 is preferably hygroscopic and flexible. Ink jet paper having a water-soluble ink absorbing layer containing PVP) or the like. Art paper, coated paper, cast paper, etc., which are used in general offset printing, are examples of absorbent recording media of a type in which water-soluble ink permeates at a relatively low speed.

In the present embodiment, "paper M" generally refers to paper made mainly of pulp (mainly cellulose) and used for printers and the like, and is defined in JIS-P-0001 No. 6139. Specifically, for example, high-quality paper, PPC copy paper, uncoated printing paper, and the like can be mentioned. As the paper M, those commercially available from various companies can be used, for example, Xerox 4200 (manufactured by Xerox), GeoCycle (manufactured by Georgia-Pacific), and various other types of paper can be used. Moreover, it is preferable that the paper M has a basis weight of 60 to 120 g/m ² .

Next, the ink composition used in the printing apparatus 1 (image forming apparatus 100) of this embodiment will be described.

The ink composition according to this embodiment preferably contains at least one compound selected from the group consisting of (A), (B) and (C) described below. In addition, from the viewpoint of safety, handleability, and various performances (color development, strike-through aptitude, ink reliability), the ink composition is preferably an aqueous ink composition in which the main solvent of the ink is water. It is preferable to use pure water or ultrapure water such as ion-exchanged water, ultrafiltrated water, reverse osmosis water, and distilled water. In particular, it is preferable to use water that has been sterilized by ultraviolet irradiation or the addition of hydrogen peroxide in order to prevent the generation of mold and bacteria and enable long-term storage of the ink. From the viewpoint of ensuring appropriate physical properties (viscosity, etc.) of the ink and ensuring the stability and reliability of the ink, the water content in the ink composition is preferably 60% by mass to 10% by mass.

By setting the content of water contained in the ink composition within the above range, the amount of water absorbed by the cellulose in the paper M becomes smaller than in conventional ink compositions, which causes cockling and curling. Swelling of cellulose, which is believed, can be suppressed. Hereinafter, properties suitable for suppressing cockling or curling are also referred to as "cockling aptitude" and "curl aptitude", respectively.

If the water content is less than 10% by mass, fixability to the recording medium (paper M) may deteriorate. On the other hand, if the water content exceeds 60% by mass, cockling or Curl is likely to occur.

The viscosity of the ink in the temperature range of 10° C. to 40° C. is influenced by the temperature characteristics of the colorant, humectant, solvent, etc. contained in the ink. Among these, the influence of the humectant is particularly large, and depending on the type, addition amount, and content ratio of the humectant, the viscosity at 10°C tends to increase and the viscosity at 40°C tends to decrease. In this specification, a smaller difference in viscosity between 10° C. and 40° C. is expressed as excellent temperature-dependent viscosity characteristics of the ink.

The ink composition according to the present embodiment has the following (A), (B) and ( It preferably contains at least one compound selected from the group consisting of C). These compounds also act as humectants. Here, the compound (A) is at least one compound selected from the group consisting of glycerin, 1,2,6-hexanetriol, diethylene glycol, triethylene glycol, tetraethylene glycol and dipropylene glycol, and (B) The compound of (C) is at least one compound selected from the group consisting of trimethylolpropane and trimethylolethane, and the compound of (C) is selected from the group consisting of betaines, sugars and ureas, and has a molecular weight of 100 at least one compound in the range of -200.

The compound (A) is particularly effective in suppressing clogging, and is also effective in suppressing curling and cockling. However, it is a substance with poor strike-through aptitude due to its excellent permeability to a recording medium. Glycerin and triethylene glycol are preferable as the compound (A) from the viewpoint of exhibiting the above effects more effectively and reliably.
The compound (B) is particularly effective in suppressing clogging, and is a substance excellent in strike-through aptitude due to its permeation suppressing effect. Trimethylolpropane is preferable as the compound (B) from the viewpoint of exhibiting these effects more effectively and reliably.
The compounds (A) and (B) have a property of having a large difference in viscosity between 10° C. and 40° C., and therefore, as the content in the ink composition increases, the temperature-dependent viscosity characteristics are greatly affected. , the ink composition also has a large viscosity difference between 10°C and 40°C.

The compound (C) is a substance particularly excellent in curling and cockling aptitude. In addition, this compound is a substance having excellent viscosity characteristics depending on temperature. Specific examples of the compound (C) include glycine betaine (molecular weight: 117, also referred to as "trimethylglycine"), γ-butyrobetaine (molecular weight: 145), homaline (molecular weight: 137), trigonelline (molecular weight: 137), carnitine (molecular weight: 137), 161), homoserine betaine (161), valine betaine (159), lysine betaine (188), ornithine betaine (176), alanine betaine (117), stachydrine (185), and betaine glutamate (189) Betaines, glucose (180), mannose (180), fructose (180), ribose (150), xylose (150), arabinose (150), which are N-trialkyl substituted amino acids such as , Sugars such as galactose (No. 180) and sorbitol (No. 182), allyl urea (No. 100), N,N-dimethylol urea (No. 120), malonyl urea (No. 128), carbamyl urea (No. 103), 1, Ureas such as 1-diethyl urea (same as 116), n-butyl urea (same as 116), creatinine (same as 113) and benzyl urea (same as 150). Also, if the molecular weight is less than 100, there is a strong tendency for the difference in viscosity between 10°C and 40°C to increase. On the other hand, when the molecular weight is 200 or more, the viscosity of the ink composition tends to increase with respect to the amount of the compound added to the ink composition. Therefore, the molecular weight of the compound (C) is preferably in the range of 100-200. Among these, betaines and sugars are preferred, and betaines are more preferred, since they are particularly effective in suppressing curling. From the same point of view, the betaine is more preferably glycine betaine, the sugar is more preferably sorbitol, and among these, glycine betaine is particularly preferable. As glycine betaine, for example, commercially available products such as Aminocoat (manufactured by Asahi Kasei Chemicals Corp.) can also be used.

From the viewpoint of curling suitability, cockling suitability, strike-through suitability, and clogging suitability, the total amount of (A), (B) and (C) is 10% to 40% by weight in the ink composition. preferably
In addition, the mass ratio of the contents of these compounds is (A):(B):(C)=(1.0):(0.1) from the viewpoint of exhibiting the above effects of these compounds in a well-balanced manner. ~1.0): (1.0 to 3.5) is preferred. When the mass ratio of the compound of (B) to the compound of the group (A) (referred to as "the compound of (A)"; the same shall apply hereinafter) is greater than the above, the suitability for curling and the suitability for cockling are reduced. However, if it is reduced, the strike-through aptitude is lowered. When the mass ratio of the compound (C) to the compound (A) is more than the above, the clogging suitability is lowered, and when it is less, the curling aptitude and the cockling aptitude are lowered.

In addition, the ink composition according to the present embodiment is used for the purpose of preventing clogging in the vicinity of the nozzles of the inkjet head, appropriately controlling the penetration and bleeding of the ink into the recording medium, and imparting the drying property of the ink. , preferably contains a water-soluble organic solvent. From the above viewpoint, the water-soluble organic solvent preferably contains 1,2-alkanediol and/or glycol ether. Specific examples of 1,2-alkanediols include 1,2-octanediol, 1,2-hexanediol, 1,2-pentanediol, and 4-methyl-1,2-pentanediol. Further, specific examples of glycol ethers include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol mono-n-propyl ether. , ethylene glycol mono-iso-propyl ether, diethylene glycol mono-iso-propyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-t-butyl ether, diethylene glycol mono-t-butyl ether, triethylene glycol mono-n-butyl ether, 1-methyl-1-methoxybutanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-t-butyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-iso-propyl ether, dipropylene glycol monomethyl ethers, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-iso-propyl ether. In addition to the above, 2-pyrrolidone, N-methyl-2-pyrrolidone, etc. can also be used as water-soluble organic solvents. These water-soluble organic solvents can be used alone or in combination of two or more. % to 50% by mass.

Furthermore, the ink composition preferably contains a surface tension modifier in order to control the wettability of the ink to the recording medium and to obtain the permeability to the recording medium and the printing stability in the inkjet recording method. Acetylene glycol-based surfactants and polyether-modified siloxanes are preferred as surface tension modifiers. Examples of acetylene glycol-based surfactants include Surfynol 420, 440, 465, 485, 104, STG (manufactured by Air Products, product names), Olphine PD-001, SPC, E1004, E1010 (manufactured by Japan Shin Kagaku Kogyo Co., Ltd., product names), acetylenol E00, E40, E100, and LH (Kawaken Fine Chemicals Co., Ltd., product names). Examples of polyether-modified siloxanes include BYK-346, 347, 348, and UV3530 (manufactured by BYK-Chemie). One or more of these can be used in the ink composition, and are included so as to adjust the surface tension of the ink composition to preferably 20 mN/m to 40 mN/m, preferably 0 in the ink composition. .1% by mass to 3.0% by mass.

In addition, pH adjusters, complexing agents, antifoaming agents, antioxidants, ultraviolet absorbers, antiseptic/antifungal agents, and the like can be added to the ink composition as necessary. As the pH adjuster, for example, alkali hydroxides such as lithium hydroxide, potassium hydroxide and sodium hydroxide and/or alkanolamines such as ammonia, triethanolamine, tripropanolamine, diethanolamine and monoethanolamine can be used. can. In particular, it preferably contains at least one pH adjuster selected from alkali metal hydroxides, ammonia, triethanolamine and tripropanolamine to adjust the pH to 6-10. If the pH is out of this range, it will adversely affect the materials constituting the ink jet printer, and the clogging recovery property tends to deteriorate.

The ink composition according to this embodiment preferably contains a pigment for the purpose of image formation and printing. As the pigment used in the ink composition according to the present embodiment, both known inorganic pigments and organic pigments can be used. Examples of such pigments include pigments such as pigment yellow, pigment red, pigment violet, pigment blue, and pigment black listed in the Color Index, as well as phthalocyanine, azo, anthraquinone, azomethine, and condensed ring pigments. Examples include pigments such as In addition, organic pigments such as yellow No. 4, 5, 205, 401; orange No. 228, 405; blue No. 1, 404, carbon black, titanium oxide, zinc oxide, zirconium oxide, iron oxide, ultramarine blue , Prussian blue, chromium oxide, and other inorganic pigments. Color indexes of pigments include, for example, C.I. I. Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42, 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104, 108, 109, 110, 117, 120, 128, 138, 150, 153, 155, 174, 180, 198, C.I. I. Pigment Red 1, 3, 5, 8, 9, 16, 17, 19, 22, 38, 57: 1, 90, 112, 122, 123, 127, 146, 184, 202, C.I. I. Pigment Violet 1,3,5:1,16,19,23,38, C.I. I. Pigment Blue 1, 2, 15, 15:1, 15:2, 15:3, 15:4, 16, C.I. I. Pigment Black 1, 7 may be mentioned, and one or more pigments may be included in the ink composition.

The pigment used in this embodiment may be in a resin-dispersed form. Pigments in such embodiments are pigment dispersions dispersed in an aqueous medium together with dispersants such as polymer dispersants and surfactants using a ball mill, roll mill, bead mill, high-pressure homogenizer, high-speed stirring disperser, or the like. Alternatively, a dispersibility imparting group (hydrophilic functional group and/or salt thereof) is directly or indirectly bonded to the pigment surface via an alkyl group, an alkyl ether group, an aryl group, etc., and an aqueous medium without a dispersant It is preferably formulated into the ink composition as a pigment dispersion that has been processed as a self-dispersing pigment that is dispersed and/or dissolved therein and dispersed in an aqueous medium.

Examples of dispersants include, as polymer dispersants, natural polymer compounds such as glue, gelatin, saponin, polyvinyl alcohols, polypyrrolidones, acrylic resins (polyacrylic acid, acrylic acid-acrylonitrile copolymer, vinyl acetate-acrylic acid copolymer, vinyl acetate-acrylic acid ester copolymer, etc.), styrene-acrylic acid resins (styrene-acrylic acid copolymer, styrene-methacrylic acid copolymer, styrene-methacrylic acid- Acrylic acid alkyl ester copolymer, styrene-α-methylstyrene-acrylic acid copolymer, styrene-α-methylstyrene-acrylic acid-acrylic acid alkyl ester copolymer, styrene-vinyl acetate-acrylic acid copolymer, etc. ), styrene-maleic acid resins, vinyl acetate-fatty acid vinyl-ethylene copolymer resins, and synthetic high molecular compounds such as salts thereof. Any graft type may be used.

Examples of surfactants used as dispersants include anionic surfactants such as fatty acid salts, higher alkyldicarboxylates, higher alcohol sulfate salts, and higher alkylsulfonates, fatty acid amine salts, fatty acid ammonium salts, and the like. Nonionic surfactants such as cationic surfactants, polyoxyalkyl ethers, polyoxyalkyl esters and sorbitan alkyl esters can be mentioned.

Among these dispersants, water-insoluble resins are particularly preferred. Specifically, the water-insoluble resin consists of a block copolymer resin of a monomer having a hydrophobic group and a monomer having a hydrophilic group, and contains at least a monomer having a salt-forming group. Resins which later have a solubility of less than 1 g in 100 g of water at 25° C. are preferred. Monomers having a hydrophobic group include, for example, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-amyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, decyl Methacrylic acid esters such as methacrylate, dodecyl methacrylate, octadecyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate and glycidyl methacrylate; vinyl esters such as vinyl acetate; vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; aromatic vinyl monomers such as methylstyrene, vinyltoluene, 4-t-butylstyrene, chlorostyrene, vinylanisole and vinylnaphthalene; These can be used individually by 1 type or in mixture of 2 or more types.
Examples of the monomer having a hydrophilic group include polyethylene glycol monomethacrylate, polypropylene glycol monomethacrylate, ethylene glycol/propylene glycol monomethacrylate, and these are used singly or in combination of two or more. be able to. Monomers having a salt-forming group include, for example, acrylic acid, methacrylic acid, styrenecarboxylic acid, and maleic acid, and these can be used singly or in combination of two or more. Furthermore, macromonomers such as styrene-based macromonomers and silicone-based macromonomers having a polymerizable functional group at one end and other monomers can be used in combination.

This water-insoluble resin is preferably used as a salt neutralized with an alkaline neutralizer such as tertiary amines such as ethylamine and trimethylamine, lithium hydroxide, sodium hydroxide, potassium hydroxide and ammonia, and has a weight average molecular weight of 10,000. Those having a molecular weight of about 150,000 are preferable from the viewpoint of stably dispersing the pigment.

A self-dispersing pigment that can be dispersed and/or dissolved in water without a dispersant is, for example, a dispersibility-imparting group or an active species having a dispersibility-imparting group by subjecting the pigment to physical or chemical treatment. It is produced by bonding (grafting) to the surface of a pigment. Examples of physical processing include vacuum plasma processing. Examples of chemical treatment include a wet oxidation method in which the pigment surface is oxidized with an oxidizing agent in water, and a method in which p-aminobenzoic acid is bonded to the pigment surface to bond a carboxyl group via a phenyl group. can. An ink composition containing a self-dispersing pigment does not need to contain a dispersant such as those described above, which is contained in order to disperse a normal pigment. , it is easy to prepare an ink with excellent ejection stability. In addition, since a significant increase in viscosity due to the dispersant can be suppressed, it becomes possible to contain a larger amount of pigment, and it becomes possible to sufficiently increase the print density or facilitate handling. Due to such advantages, the self-dispersing pigment is particularly effective for black ink compositions that require high concentrations. preferably contains at least a self-dispersible pigment that can be dispersed and/or dissolved in water.

In the present embodiment, a self-dispersing pigment surface-treated by oxidation treatment with hypohalous acid and/or hypohalite salt or oxidation treatment with ozone is preferable in terms of high color development. It is also possible to use a commercial product as a self-dispersing pigment. Examples of such commercial products include Microjet CW-1 (trade name; manufactured by Orient Chemical Industry Co., Ltd.), CAB-O-JET200, and CAB. -O-JET300 (trade name; manufactured by Cabot Corporation) can be exemplified.

These pigments preferably have a volume average particle diameter in the ink of 50 nm to 200 nm from the viewpoint of storage stability of the ink and prevention of nozzle clogging. These volume average particle diameters can be obtained by particle size measurement using Microtrac UPA150 (manufactured by Microtrac), particle size distribution analyzer LPA3100 (manufactured by Otsuka Electronics Co., Ltd.), or the like.

These pigments are preferably contained in the ink composition in an amount of 6% by mass or more.
If the content is less than 6% by mass, the print density (color development) may be insufficient. Moreover, although the upper limit of the content is not particularly limited, the content may be, for example, 25% by mass or less. If the content is more than 25% by mass, reliability problems such as nozzle clogging and unstable ejection may occur.

The ink composition according to the present embodiment preferably contains a resin emulsion from the viewpoint of improving fixability to a recording medium. The resin emulsion preferably contains resin particles having a minimum film-forming temperature of less than 20°C. By using a resin emulsion containing resin particles having a minimum film-forming temperature of less than 20° C., the resin particles form a film at an ambient temperature in a use environment of usually 20° C. or higher, so that the coating of the ink composition is improved. Improves fixability and abrasion resistance to recording media.
Here, the minimum film-forming temperature is measured as follows. First, a resin emulsion is applied to a thickness of 0.3 mm on a stainless steel plate of a temperature gradient test device. Immediately after application, the basket containing silica gel is placed on the plate and covered with a clear plastic lid. After drying the coating film, read the temperature at the boundary between the uniform continuous film portion and the cloudy portion, and take it as the minimum film-forming temperature.

These resin emulsions contain one or more resin particles selected from the group consisting of acrylic resins, methacrylic resins, vinyl acetate resins, vinyl chloride resins, and styrene-acrylic resins. is preferred. These resins may be used as homopolymers or copolymers, and both single-phase structures and multi-phase structures (core-shell type) can be used.

Furthermore, at least one of the resin emulsions contained in the ink composition used in the present embodiment is in the form of an emulsion of resin particles obtained by emulsion polymerization of an unsaturated monomer, and is incorporated in the ink composition. preferably. Even if the resin particles are added alone to the ink composition, the dispersion of the resin particles may be insufficient. Therefore, the emulsion form is preferable from the viewpoint of the production of the ink composition. From the viewpoint of the storage stability of the ink composition, the emulsion is preferably an emulsion of acrylic resin particles, that is, an acrylic emulsion.
An emulsion of resin particles (such as an acrylic emulsion) can be obtained by a known emulsion polymerization method. For example, unsaturated monomers (such as unsaturated vinyl monomers) can be obtained by emulsion polymerization in water in which a polymerization initiator and a surfactant are present.

Examples of unsaturated monomers include acrylic acid ester monomers, methacrylic acid ester monomers, aromatic vinyl monomers, vinyl ester monomers, and vinyl cyanide monomers that are generally used in emulsion polymerization. , halogenated monomers, olefinic monomers, and diene monomers.

As unsaturated monomers, more specifically, methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, n-amyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate , octyl acrylate, decyl acrylate, dodecyl acrylate, octadecyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, glycidyl acrylate; methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n - methacrylic acid esters such as amyl methacrylate, isoamyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, octyl methacrylate, decyl methacrylate, dodecyl methacrylate, octadecyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, glycidyl methacrylate; vinyl esters; vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; halogenated monomers such as vinylidene chloride and vinyl chloride; Aromatic vinyl monomers such as vinyl naphthalene; Olefins such as ethylene and propylene; Dienes such as butadiene and chloroprene; Vinyl ethers, vinyl ketones and vinyl pyrrolidone; Unsaturated carboxylic acids such as maleic acid; acrylamides such as acrylamide, methacrylamide, and N,N'-dimethylacrylamide; 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, etc. and hydroxyl group-containing monomers. These are used singly or in combination of two or more.

A crosslinkable monomer having two or more polymerizable double bonds can also be used as the unsaturated monomer. Examples of crosslinkable monomers having two or more polymerizable double bonds include polyethylene glycol diacrylate, triethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, 1,9-nonanediol diacrylate, polypropylene glycol diacrylate, 2,2′-bis(4-acryloxypropyloxyphenyl)propane, 2,2′ - diacrylate compounds such as bis(4-acryloxydiethoxyphenyl)propane; triacrylate compounds such as trimethylolpropane triacrylate, trimethylolethane triacrylate, tetramethylolmethane triacrylate; ditrimethyloltetraacrylate, tetramethylolmethanetetra acrylates, tetraacrylate compounds such as pentaerythritol tetraacrylate; hexaacrylate compounds such as dipentaerythritol hexaacrylate; ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 1,3-butylene glycol di methacrylate, 1,4-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, polybutylene glycol dimethacrylate, 2,2′-bis(4 -methacryloxydiethoxyphenyl)propane; trimethacrylate compounds such as trimethylolpropane trimethacrylate and trimethylolethane trimethacrylate; methylenebisacrylamide; and divinylbenzene. These are used individually by 1 type or in mixture of 2 or more types.

In addition to the polymerization initiator and surfactant used in emulsion polymerization, a chain transfer agent, a neutralizing agent, and the like may also be used according to conventional methods. Particularly preferred neutralizers are ammonia and inorganic alkali hydroxides such as sodium hydroxide and potassium hydroxide.

In the present embodiment, the resin emulsion contains 1 resin particle in the ink composition from the viewpoint of more effectively obtaining ink composition physical properties suitable for inkjet, reliability (clogging, ejection stability, etc.), fixability, and the like. It is preferably contained so as to be in the range of mass % to 10 mass %.

The volume average particle size of the resin emulsion contained in the ink composition is preferably 5 nm to 400 nm, more preferably 50 nm to 200 nm, from the viewpoint of dispersion stability and fixability of the resin particles in the ink composition. is more preferred. This volume average particle size is measured, for example, using Coulter Counter N4 (manufactured by Coulter, trade name).

Next, the intermediate conveying device 200 will be described. As shown in FIG. 1, the intermediate conveying device 200 includes an intermediate conveying section 252 capable of conveying the paper M. As shown in FIG. The intermediate conveying section 252 includes at least one reversing section (two first reversing sections 241 and a second reversing section 242 in this embodiment) that reverses the conveyed sheet M. FIG. The first reversing section 241 and the second reversing section 242 are positioned downstream of the recording section 110 in the transport direction in the transport path, and reverse the paper M on which an image is formed (printed). The intermediate conveying device 200 also includes an intermediate conveying path 218 along which the paper M is conveyed. Therefore, the intermediate conveying device 200 has a drying function of drying the sheet M on which an image is formed in the image forming apparatus 100 while conveying it, and a reversing function of reversing the sheet M conveyed from the image forming apparatus 100. .

Intermediate transport path 218 of intermediate transport apparatus 200 is connected to third discharge path 153 of image forming apparatus 100 . The intermediate conveying route 218 includes an introduction route 243 whose upstream end is connected to the third discharge route 153, and a first branch route 244 and a second branch route 245 that branch at a branch point A that is the downstream end of the introduction route 243. and That is, the branch point A is connected to the downstream end of the introduction path 243, the upstream end of the first branched path 244, and the upstream end of the second branched path 245, respectively. The path lengths in the conveying direction of the first branch path 244 and the second branch path 245 are substantially the same length.

Furthermore, the intermediate conveying route 218 is connected to the first junction route 246 connected to the first connection point B, which is the downstream end of the first branch route 244, and the second connection point C, which is the downstream end of the second branch route 245. It has a connected second merging path 247 . The path lengths in the conveying direction of the first merging path 246 and the second merging path 247 are substantially the same length.

Also, the first connection point B is connected to the first inverting path 248 of the first inverting section 241 . Also, the second connection point C is connected to the second inverting path 249 of the second inverting section 242 . That is, the first connection point B is connected to the downstream end of the first branch path 244 , the upstream end of the first merging path 246 , and one end of the first reverse path 248 . Also, the second connection point C is connected to the downstream end of the second branch path 245 , the upstream end of the second merging path 247 , and one end of the second reverse path 249 . The path lengths of the first reversing path 248 and the second reversing path 249 are configured to be equal to or longer than the length of the paper M on which image formation (printing) can be performed by the image forming apparatus 100 in the transport direction.

Further, the intermediate conveying route 218 is provided with a confluence D where the first confluence route 246 and the second confluence route 247 merge, and has an outlet route 250 connected to the confluence D. That is, the confluence D is connected to the downstream end of the first confluence path 246 , the downstream end of the second merge path 247 , and the upstream end of the lead-out path 250 . The lead-out path 250 extends downward between the first reversing path 248 and the second reversing path 249 toward the post-processing device 300, then turns around the first reversing path 248 and extends upward. . The lead-out path 250 is composed of a first lead-out path 250a arranged on the upstream side and a second lead-out path 250b arranged on the downstream side of the first lead-out path 250a. A downstream end of the second lead-out path 250b is connected to the downstream transport path 319 of the post-processing device 300 .

In the present embodiment, the introduction route 243, the first branch route 244, and the second branch route 245 constitute the pre-reversal route 218a, the first confluence route 246, the second confluence route 247, and the outlet route. 250 constitute a post-inversion path 218b. The pre-reversal path 218a is positioned upstream in the transport direction from the first reversing section 241 or the second reversing section 242 in the transport direction. Further, the post-reversal path 218b is positioned downstream in the transport direction from the first reversing section 241 or the second reversing section 242 in the transport direction. That is, the intermediate conveying path 218 has a pre-reversing path 218a positioned upstream in the conveying direction from the first reversing section 241 and the second reversing section 242, and a post-reversing path 218b positioned downstream in the conveying direction. is doing.

In addition, as shown in FIG. 3 , the intermediate transport device 200 includes an intermediate transport section 252 capable of transporting the paper M along the intermediate transport path 218 . The first reversing section 241 and the second reversing section 242 in the intermediate conveying section 252 are configured to be able to reverse the sheet M being conveyed.

A first conveying roller pair 254 driven by a first driving motor (not shown) is arranged on the introduction path 243 , the first branch path 244 and the second branch path 245 . A second conveying roller pair 256 driven by a second driving motor (not shown) is arranged on the first joining path 246, the second joining path 247, and the first lead-out path 250a. A third conveying roller pair 257 driven by a third drive motor (not shown) is arranged on the second lead-out path 250b. The numbers of the first transport roller pair 254, the second transport roller pair 256, and the third transport roller pair 257 can be arbitrarily set depending on the form of each transport path. Then, while each roller pair of the intermediate transport section 252 sandwiches and supports the sheet M from both sides, one roller of the roller pair is rotationally driven to transport the sheet M along the transport path.

In addition, an introduction detection unit 258 that detects the paper M is provided in the introduction path 243 . The introduction detection unit 258 is, for example, a photointerrupter, and has the same specific configuration as the transport detection unit 199 . A guide flap 259 is provided at a branch point A on the downstream side of the introduction detection section 258 in the transport direction. The guide flap 259 is driven by a solenoid or the like, and switches between the first branched path 244 and the second branched path 245 to guide the sheet M conveyed along the lead-in path 243 .

Furthermore, at the downstream end of the first branch path 244, while allowing the movement of the paper M from the first branch path 244 to the first reversing path 248, the paper M from the first reversing path 248 to the first branch path 244 A first restricting flap 261 is provided to restrict the movement of the . Furthermore, at the downstream end of the second branch path 245, while allowing the movement of the paper M from the second branch path 245 to the second reversing path 249, the paper M from the second reversing path 249 to the second branch path 245 A second restricting flap 262 is provided to restrict the movement of the . These first regulation flap 261 and second regulation flap 262 are urged by an urging force of an urging member (not shown) so as to close the downstream end of the first branch path 244 or the second branch path 245. .

A first detection unit 281 that detects the paper M is arranged on the first branch path 244 , and a second detection unit 282 that detects the paper M is arranged on the second branch path 245 . A third detection unit 283 for detecting the paper M is arranged on the first junction path 246 . Further, a fourth detection section 284 for detecting the paper M is arranged on the first lead-out path 250a, and a fifth detection section 285 for detecting the paper M is arranged on the second lead-out path 250b. Note that the first to fifth detectors 281 , 282 , 283 , 284 , and 285 are, for example, photointerrupters, and have the same specific configuration as the transport detector 199 . The number of detection units in each transport path can be arbitrarily set according to the form of each transport path.

The first reversing unit 241 includes a first reversing detection unit 264 that detects the sheet M sent to the first reversing path 248, and a first reversing roller pair 265 (this embodiment) provided on the first reversing path 248. 2 pairs) are arranged. The first reversing roller pair 265 is driven forward or reverse by a first reversing motor (not shown) based on a signal transmitted when the first reversing detection unit 264 detects the paper M.

Further, the second reversing section 242 includes a second reversing detection section 267 that detects the sheet M sent to the second reversing path 249, and a second reversing roller pair 268 (a book sheet) provided on the second reversing path 249. In the embodiment, 5 pairs) are arranged. The second reversing roller pair 268 is driven forward or reverse by a second reversing motor (not shown) based on a signal transmitted when the second reversing detector 267 detects the paper M. Note that the first and second reversal detection units 264 and 267 are, for example, photo interrupters, and have the same specific configuration as the transport detection unit 199 .

Next, the configuration of the post-processing device will be described. As shown in FIG. 1, the post-processing device 300 has a substantially box-shaped frame 320 . The frame 320 has a post-processing paper feed port 322 and a post-processing paper discharge port 323 . The post-processing paper feed port 322 and the post-processing paper discharge port 323 are each formed with an opening, and the post-processing paper feed port 322 is arranged corresponding to the downstream end of the intermediate transport path 218 of the intermediate transport device 200, The intermediate conveying path 218 and the downstream conveying path 319 are connected. The downstream transport path 319 is arranged from the post-processing paper feed port 322 to the post-processing paper discharge port 323, and the paper M transported from the intermediate transport device 200 is supplied from the post-processing paper feed port 322, and the paper M After being subjected to post-processing, etc., the paper is discharged from the post-processing discharge port 323 .

A stacker 328 , a post-processing section 325 and the like are arranged inside the frame 320 . The stacker 328 temporarily stacks the paper M, and has a stacking surface 328a having a substantially flat surface on which the paper M can be placed, and a stacker 328 formed substantially perpendicular to the edge of the stacking surface 328a. and a wall surface 328b.

The post-processing unit 325 performs a punching process for punching holes in the sheets M placed on the stacker 328, a stapling process for binding the sheets M every predetermined number, Post-processing such as shift processing for shifting and adjusting the position of each sheet or bundle in the width direction is performed by an appropriate mechanism. Note that the post-processing unit 325 can perform a paper folding unit that folds the paper M, a cutting process that cuts the paper M, a signature process that folds the paper M, a bookbinding process that binds the paper M, a collation process, and the like. A mechanism may be provided.

A downstream transport section 335 is arranged along the downstream transport path 319 inside the frame 320 . The downstream transport section 335 has a pair of transport rollers 327 driven by drive rollers (not shown). A paper discharge roller pair 329 is arranged in the vicinity of the post-processing paper discharge port 323 in the downstream transport path 319 . The transport roller pair 327 is arranged upstream of the stacker 328 and the post-processing section 325 in the downstream transport path 319 and transports the paper M fed from the post-processing paper feed port 322 to the stacker 328 . A transport detection unit 356 that detects the paper M is arranged near the post-processing paper feed port 322 in the downstream transport path 319 . The transport detection unit 356 is, for example, a photointerrupter, and has the same specific configuration as the transport detection unit 199 .

Further, inside the frame 320, a guide portion 330 is provided to guide the sheet M transported along the downstream transport path 319. As shown in FIG. The guide portion 330 has a protrusion shape. The guide portion 330 includes a guide surface 330a having a substantially flat surface, and the guide surface 330a is arranged to face the downstream transport path 319 (stacker 328). The width of the guide surface 330a of the present embodiment, which is substantially perpendicular to the transport direction of the paper M, is substantially the same as the width of the paper M which is substantially perpendicular to the transport direction. As a result, the paper M can be easily transported. The guide section 330 is arranged downstream of the transport roller pair 327 and upstream of the paper discharge roller pair 329 in the downstream transport path 319 . Accordingly, the paper M transported from the transport roller pair 327 is transported to the stacker 328 via the guide section 330 .

The stacker 328 of the present embodiment is arranged downstream of the transport roller pair 327 in the downstream transport path 319 and temporarily stacks the paper M to be processed by the post-processing section 325 . A stacking surface 328a of the stacker 328 is arranged obliquely so that at least one edge side of the plurality of sheets M placed on the stacker 328 are aligned. In this embodiment, one end of the stacker 328 is arranged on the side of the post-processing discharge port 323 , and the other end (wall surface 328 b ) of the stacker 328 is arranged on the side of the post-processing section 325 . The post-processing discharge port 323 is arranged above the post-processing section 325 , and the stacker 328 is arranged obliquely downward toward the post-processing section 325 . As a result, one end side of the paper sheets M placed on the stacker 328 contacts the wall surface 328b of the stacker 328, thereby aligning one end side of the paper sheets M. FIG.

4 and 5 are schematic diagrams showing the operation of the post-processing device. Specifically, it is a schematic diagram showing the operation of the discharge roller pair 329 . The paper discharge roller pair 329 is arranged on one end side of the stacker 328 and is configured to discharge the paper M placed on the stacker 328 one by one or for each bundle of a predetermined number of sheets. The paper discharge roller pair 329 includes a first paper discharge roller 329a and a second paper discharge roller 329b. The first paper discharge roller 329a and the second paper discharge roller 329b are arranged in the vertical direction Z, and the first paper discharge roller 329a is arranged above the second paper discharge roller 329b. The first paper discharge roller 329a and the second paper discharge roller 329b are configured to be separated from each other and pressed against each other. In this embodiment, the first paper discharge roller 329a is configured to be movable with respect to the second paper discharge roller 329b by a drive motor.

Then, when the paper M transported from the transport roller pair 327 is placed on the stacker 328, the paper discharge roller pair 329 is separated as shown in FIG. At this time, the first discharge roller 329a is arranged at the first position Ps1 where the gap G between the first discharge roller 329a and the second discharge roller 329b is the first gap G1. The first position Ps1 is a defined home position, and the first gap G1 is a value that maximizes the gap G between the first paper discharge roller 329a and the second paper discharge roller 329b. Note that the gap G is the gap in the direction in which the paper M is sandwiched between the first paper discharge roller 329a and the second paper discharge roller 329b. It is the shortest dimension to the outermost peripheral surface. In this state, after a part of the paper M has passed between the first paper discharge roller 329a and the second paper discharge roller 329b, as shown in FIG. The pair of discharge rollers 329 (first discharge roller 329a, second discharge roller 329b) is rotated in the direction of pulling back toward the stacker 328 side. As a result, the paper M is placed on the stacker 328 . At this time, the first discharge roller 329a moves to a nip position Psn below the first position Ps1 where the paper M is nipped between the first discharge roller 329a and the second discharge roller 329b. Then, until a predetermined number of sheets of paper M are placed on the stacker 328, the separating and pressing operations by the first paper discharge roller 329a and the second paper discharge roller 329b are repeated.

Further, when the sheet M that has undergone post-processing in the post-processing section 325 is to be discharged to the discharge tray 331 side, a predetermined number of sheets M are nipped, and the pair of discharge rollers 329 (first discharge roller 329a, second discharge roller 329a, 2. The discharge roller 329b) is rotated in the direction of conveying the sheet to the side opposite to the stacker 328 side. As a result, the sheet M can be discharged to the discharge tray 331 side. At this time, the first discharge roller 329a is arranged at the nip position Psn where the first discharge roller 329a and the second discharge roller 329b nip the paper M placed on the stacker 328 (see FIG. 5). .

The paper discharge tray 331 is provided outside the frame 320 and stacks the paper M discharged from the post-processing paper discharge port 323 . The paper discharge tray 331 has a loading surface 331a on which the paper M is loaded (placed), and protrudes outward from the frame 320 .

Next, a basic operating method of the printing apparatus will be described. 6 to 9 are schematic diagrams showing how the printing apparatus operates. In the following description, the transport mode of the sheet M transported from the image forming apparatus 100 to the post-processing device 300 via the intermediate transport device 200 will be described. Note that the paper sheets M supplied to and conveyed by the recording head 111 of the image forming apparatus 100 are designated as the first sheet Ma, the second sheet Mb, and the third sheet Mc in order from the first sheet, and the fourth sheet M is the fourth sheet. The sheet Md will be described.

First, when the printing process (image forming process) is executed, the control unit 10 drives each driving motor. As a result, a pickup roller 142a connected to each drive motor, a transport roller pair 131, a drive roller 133, a first transport roller pair 254, a second transport roller pair 256, a third transport roller pair 257, and a first reversing roller pair 265 , the second reversing roller pair 268, the conveying roller pair 327, and the like are driven.

Then, the recording unit 110 ejects ink from the recording head 111 onto the paper M to form an image (performs printing). In this case, the printing process may be single-sided printing or double-sided printing.

Then, as shown in FIG. 6, the first sheet Ma conveyed through the third discharge path 153 at the pre-reversal speed is transferred to the introduction path 243 at substantially the same speed. Then, when the introduction detection unit 258 detects the leading edge of the first sheet Ma, the control unit 10 drives the solenoid to position the guide flap 259 at the first position P1. That is, the guide flap 259 guides the first sheet Ma to the first branch path 244 . The leading edge of the first sheet Ma transported to the first connection point B contacts the first regulation flap 261 to move the first regulation flap 261 against the biasing force of the biasing member. That is, the first regulation flap 261 moves so as to open the downstream end of the first branch path 244 . Therefore, the first sheet Ma is sent to the first reversing path 248 at the pre-reversal speed by the first reversing roller pair 265 that is driven to rotate in the normal direction. Then, when the first sheet Ma passes through the first regulation flap 261, the first regulation flap 261 moves from the position to open the downstream end of the first branch path 244 to the position to close it.

As shown in FIG. 7, when the first reversal detection unit 264 detects the trailing edge of the first sheet Ma, the control unit 10 switches the first reversing roller pair 265, which has been normally driven, to reverse rotation. Then, the first reversing section 241 feeds the first sheet Ma from the first reversing path 248 to the first connection point B side at the post-reversal speed. Also, at this time, the first regulation flap 261 guides the first sheet Ma to the first joining path 246 . That is, the first reversing section 241 reverses (switches back) the orientation of the first sheet Ma by feeding the first sheet Ma sent from the first branch path 244 to the first joining path 246 .

Also, when the introduction detection unit 258 detects the leading edge of the second sheet Mb, the control unit 10 drives the solenoid to change the position of the guide flap 259 . That is, the control unit 10 moves the guide flap 259 positioned at the first position P1 to the second position P2. The guide flap 259 then guides the second sheet Mb to the second branch path 245 .

As shown in FIG. 8, the first sheet Ma reversed by the first reversing section 241 is conveyed through the post-reversal path 218b at the post-reversal speed. Then, when the first sheet Ma passes through the first connection point B, the controller 10 rotates the first reversing roller pair 265 forward. Further, the control section 10 reversely rotates the second reversing roller pair 268 when the second reversing detection section 267 detects the trailing edge of the second sheet Mb. That is, the second reversing section 242 reverses the second sheet Mb and sends it to the second merging path 247 at the post-reversal speed in the same manner as the first reversing section 241 .

Furthermore, when the introduction detection unit 258 detects the leading edge of the third paper Mc, the control unit 10 drives the solenoid to change the position of the guide flap 259 . Specifically, the control unit 10 moves the guide flap 259 positioned at the second position P2 to the first position P1. That is, the guide flap 259 alternately guides the conveyed sheet M to the first branch path 244 and the second branch path 245 .

As shown in FIG. 9, the second sheet Mb reversed by the second reversing section 242 and sent to the second merging path 247 is conveyed through the derivation path 250 via the merging point D. As shown in FIG. Note that, at this time, the intermediate conveying unit 252 conveys the first sheet Ma and the second sheet Mb at a post-reversal speed that is lower than the pre-reversal speed. Therefore, the interval in the transport direction between the first sheet Ma and the second sheet Mb is narrower than when the sheets are transported through the pre-reversal path 218a at the pre-reversal speed.

Then, when the first reversal detection section 264 detects the trailing edge of the third sheet Mc, the control section 10 reversely rotates the first reversing roller pair 265 to feed the third sheet Mc to the first joining path 246 .
Further, when the introduction detection unit 258 detects the leading edge of the fourth sheet Md, the control unit 10 drives the solenoid to change the position of the guide flap 259 to the second position P2.

Then, the intermediate conveying device 200 sequentially feeds the first paper Ma introduced first to the post-processing device 300 . That is, the sheet M is reversed in the intermediate conveying device 200 and sent to the post-processing device 300 . Further, since the downstream-side transport unit 335 transports the sheet M at a processing speed faster than the post-reversal speed, the interval between the sheets M increases. Then, the sheets M are successively conveyed to the stacker 328, and when a predetermined number of sheets M are placed on the stacker 328, the post-processing unit 325 performs processing such as stapling, and the sheet discharge roller pair 329 is driven to move the sheets M to the discharge tray. 331 is discharged.

Next, problems related to the post-processing device 300 of this embodiment will be described. As described above, when the image forming apparatus 100 is an inkjet printer including the recording head 111 that ejects ink as droplets, the paper M on which an image has been formed by the image forming apparatus 100 absorbs ink (moisture). As the ink dries, curling (a state in which the paper is curved or a state in which the paper is curled) may occur. Therefore, when the paper sheets M on which an image is formed by the image forming apparatus 100 (inkjet printer) are sequentially stacked on the stacker 328, if the degree of curling of the paper sheets M loaded first increases, There is a possibility that the paper M conveyed from the first contact with the curled portion of the paper M placed first, causing a conveyance problem.

Further, the mechanism of curling of the paper M will be described in detail. The paper M of this embodiment is mainly composed of cellulose, and the cellulose is formed by hydrogen bonding. Therefore, when the image forming apparatus 100 applies ink to one surface of the sheet of paper M, the absorption of the ink breaks the hydrogen bonds between the celluloses. As a result, the space between the cellulose particles widens, and the one side of the paper M coated with ink becomes easier to stretch than the other side of the paper M opposite to the one side. Therefore, when one side of the paper M is placed in the direction of gravity (downward), the paper M curls convexly in the direction of gravity (primary curl).
Further, after the primary curl occurs, as the drying of the ink absorbed by the sheet of paper M progresses, the celluloses are freely linked by hydrogen bonding, and the spacing between the celluloses narrows. Then, one side of the paper M coated with ink shrinks more than the other side. Therefore, when one side of the paper M is placed in the direction of gravity, the paper M is concave with respect to the direction of gravity (convex in the direction opposite to the direction of gravity), contrary to the case of the primary curl. ) (secondary curl).

Here, in the post-processing device 300 of the present embodiment, curling of the paper M (particularly secondary curling) is a problem. Specifically, the sheet M on which an image has been formed by the image forming apparatus 100 is conveyed to the post-processing apparatus 300 via the intermediate conveying apparatus 200 . In this process, as the ink applied to the paper M dries over time, the secondary curl increases. When a transport failure (jam) occurs in the paper M and the transport of the paper M is interrupted, the curl (secondary curl) of the paper M already placed on the stacker 328 increases with the passage of time. To go. Then, when the jam is resolved, the transport of the paper M is restarted, and the paper M transported after the jam is resolved is transported to the stacker 328, the paper M transported later is already placed on the stacker 328. The curled portion of the sheet of paper M is caught on the sheet of paper M, causing a trouble in transportation. In particular, the sheet M that has already been transported to the stacker 328 curls (secondary curl concave with respect to the mounting surface 328a) such that the edge portion of the sheet M rises above the center portion of the sheet M with respect to the mounting surface 328a. In this case, the sheet of paper M is likely to be caught by the curled portion of the sheet of paper M, thus causing a trouble in transportation. In the case of a curl in which the central portion of the paper M is lifted and deformed relative to the mounting surface 328a relative to the mounting surface 328a (secondary curl in a convex shape with respect to the mounting surface 328a), the self weight of the paper M Therefore, the deformation (curl) of the sheet M can be dealt with in the same manner as a transportation problem related to the deformation (curl) of the sheet M, although the tendency of occurrence of the transportation trouble is lower than that of the concave secondary curl.

Further, the occurrence of curling of the paper M is not limited to single-sided printing, and occurs similarly in double-sided printing. That is, when the printing duty on one side of the paper M and the printing duty on the other side of the paper M are different, curling of the paper M may occur. In particular, when the difference between the printing duty on one side of the paper M and the printing duty on the other side is greater than a predetermined value (for example, about 30% or more), the curling of the paper M becomes significant. Note that the "duty" is duty (%) = number of actual recorded dots / (vertical resolution x horizontal resolution) x 100 (wherein "number of actual recorded dots" is the number of actual recorded dots per unit area, and " "vertical resolution" and "horizontal resolution" are resolutions per unit area).

Therefore, the post-processing device 300 is provided with a suppression unit 450 that suppresses deformation (curling) of the paper M placed on the stacker 328 . The suppressing unit 450 can reduce conveyance problems of the paper M caused by curling (in particular, secondary curling) of the paper M placed on the stacker 328 .

Next, the configuration of the suppression unit will be described. 10, 11 and 12 are schematic diagrams showing the configuration of each suppression unit. In the example of FIG. 10 , the discharge roller pair 329 functions as the suppressing section 450 . The paper ejection roller pair 329 as the suppression unit 450 suppresses deformation (curling) of the paper M between the stacker 328 and the paper ejection tray 331 . That is, the discharge roller pair 329 suppresses the curling of the paper M independently without being involved in the stacker 328 . Specifically, the paper discharge roller pair 329 as the suppression unit 450 includes a first paper discharge roller 329a as a first roller and a second paper discharge roller 329b as a second roller.
As shown in FIG. 10, the gap G between the first discharge roller 329a and the second discharge roller 329b is divided into a first gap G1 and a second gap G2, which is narrower than the first gap G1. , is configured to be variable. Note that in the present embodiment, when the first discharge roller 329a is positioned at the first position Ps1, the first gap G1 is set (see FIG. 4). Also, the first discharge roller 329a can arbitrarily move between the first position Ps1 and the nip position Psn (see FIG. 5). By moving the first discharge roller 329a from the first position Ps1 toward the second discharge roller 329b, a second gap G2, which is narrower than the first gap G1, can be set. Therefore, the nip position Psn can also be the second position Ps2.

When suppressing the deformation of the paper M placed on the stacker 328 , the paper M placed on the stacker 328 is passed through the first discharge roller 329 a and the first discharge roller 329 a . The gap G with the second discharge roller 329b is set to a second gap G2, which is narrower than the first gap G1. That is, the first discharge roller 329a is moved from the first position Ps1 to the second position Ps2. As a result, the gap G between the first discharge roller 329a and the second discharge roller 329b becomes narrower than the first gap G1, so deformation (curling) of the paper M is regulated.
When suppressing the deformation of the paper M placed on the stacker 328, the nip position Psn for nipping the paper M of the first paper discharge roller 329a is set to the second position Ps2. preferably. That is, at the first position Ps1 at the first gap G1, the second paper ejection roller 329b is in contact with the paper M, but the first paper ejection roller 329a is not in contact with the paper M. FIG. On the other hand, the first discharge roller 329a and the second discharge roller 329b contact the sheet M at the nip position Psn (second position Ps2) where the second gap G2 is provided. In this way, since the paper M is pressed by the first paper discharge roller 329a and the second paper discharge roller 329b, a part of the paper M is held in a flat state, thereby suppressing curling. . In addition, since the surface of the paper M is less likely to be exposed to the outside air by being pressed, drying of the ink applied to the paper M can be suppressed, and the occurrence of curling can be suppressed. Note that the nipping force when the second position Ps2 is set as the nipping position Psn is weaker than the nipping force when conveying the normal paper M, and is set to a pressure that allows the nipped paper M to be pulled out with fingers, for example. may The load on the paper discharge roller pair 329 can be reduced.

Furthermore, in the example of FIG. 11 , the guide section 330 can function as the restraining section 450 separately from the discharge roller pair 329 . The guide portion 330 as the suppressing portion 450 suppresses deformation (curling) of the paper M on the stacker 328 . That is, the guide portion 330 suppresses the curling of the paper M while being involved with a part of the stacker 328 (the placement surface 328a on which the paper M is placed, etc.). Specifically, the guide portion 330 as the suppressing portion 450 includes a guide surface 330a as a part of the contact portion capable of contacting the surface of the sheet M. As shown in FIG. The distance K between the sheets M placed on the stacker 328 and the guide surface 330a can be changed between a first distance K1 and a second distance K2 that is narrower than the first distance K1. It is configured. The guide section 330 of this embodiment is connected to a drive motor and configured to be rotatable around the axis of the first paper discharge roller 329a.

In the present embodiment, the guide portion 330 is moved to the first position Pk1 (home position) when the paper M is conveyed, and the guide portion 330 is moved so that the guide surface 330a approaches the paper M side in order to suppress the deformation of the paper M. and the second position Pk2 moved in the direction. As a result, the distance K between the sheet M placed on the stacker 328 and the guide surface 330a becomes variable. As a result, the distance K between the sheets M placed on the stacker 328 and the guide surface 330a can be changed between the first distance K1 and the second distance K2, which is narrower than the first distance K1. Become. In this embodiment, the distance K is set between the leading end portion 330b of the guide portion 330 (the end portion of the guide portion 330 opposite to the first discharge roller 329a and part of the contact portion) and the sheet M. It is possible to set the dimension between the specified point (fixed point) Mt. Thereby, the distance K between the paper M and the guide surface 330a can be defined.

When suppressing the deformation of the paper M placed on the stacker 328, the guide section 330 is moved from the first position Pk1 to the second position Pk2, and the paper M and the guide surface 330a are moved. is changed to a second interval K2 narrower than the first interval K1. As a result, the distance K between the paper M and the guide surface 330a is narrowed, so deformation (curling) of the paper M is restricted. When suppressing deformation of the paper M placed on the stacker 328, the leading end portion 330b of the guide portion 330 can press the paper M placed on the stacker 328. It is preferable to move the guide portion 330 with this position as the second position Pk2. That is, the guide surface 330a and the leading end portion 330b of the guide portion 330 are not in contact with the paper M at the first position Pk1, which is the first distance K1. On the other hand, the leading end portion 330b of the guide portion 330 contacts the sheet M at the second position Pk2, which is the second distance K2. In this way, since the paper M is pressed by the guide portion 330, a part of the paper M is held in a substantially flat state, so that curling can be efficiently suppressed.

Note that, in the present embodiment, as shown in FIG. 12, the pair of discharge rollers 329 and the guide section 330 are configured as a restraining section 450 . Specifically, when suppressing the deformation of the paper M placed on the stacker 328 , the paper M placed on the stacker 328 is passed through the first discharge roller. The gap G between 329a and the second discharge roller 329b is set to the second gap G2. That is, the first discharge roller 329a is moved from the first position Ps1 to the second position Ps2. Further, the space K between the paper M placed on the stacker 328 and the guide surface 330a is set to the second space K2. That is, the guide portion 330 is moved from the first position Pk1 to the second position Pk2. As a result, the sheet M placed on the stacker 328 is restricted from being deformed (curled) by the pair of discharge rollers 329 and the guide section 330, and the deformation (curl) of the sheet M is suppressed. can do.

Next, the configuration of the control unit of the printing apparatus will be described. FIG. 13 is a block diagram showing a partial configuration of the control section of the printing apparatus. Note that FIG. 13 mainly shows the configuration related to the control of the suppression unit 450 .

As shown in FIG. 13 , the printing device 1 includes a control section 10 . The control unit 10 includes a CPU, ROM and RAM as storage means, and an input/output interface. The CPU processes various signals input via the input/output interface based on data in the ROM and RAM, A control signal is output to each drive unit via the drive unit. The CPU performs various controls based on, for example, control programs stored in the ROM.

The control unit 10 includes each detection unit (conveyance detection unit 199, introduction detection unit 258, first to fifth detection units 281, 282, 283, 284, 285, first and second reversal detection units 264, 267, conveyance detection unit 356) is connected, and detection data is transmitted from each detection unit. In addition, each drive motor (conveyance drive motor, first to third drive motors, first and second reversing motors, and each drive motor) is connected to the control unit 10, and the control unit 10 to each drive motor A drive control signal generated based on the detected data is transmitted to drive and control each drive motor. Then, as each drive motor is driven, members such as roller pairs connected to each drive motor (conveyance roller pair 131, first to third conveyance roller pairs 254, 256, 257, first and second reversing roller pairs 265, 268, the first discharge roller 329a, the guide section 330, and the transport roller pair 327) are driven.

Next, a method for controlling the printing apparatus will be described. In detail, a method of controlling the suppression unit will be described. FIG. 14 is a flow chart showing the control method of the printing device. As shown in FIG. 14, the control method of the suppression unit 450 is executed by suppression execution processing in step S100 and suppression cancellation processing in step S200. In the suppression execution process of step S100, when a jam occurs upstream of the stacker 328 in the transport path of the paper M (the third discharge path 153, the intermediate transport path 218, and the downstream transport path 319), the suppression unit At 450, deformation (curling) of the paper M is suppressed. Specifically, when a jam occurs, the suppressing unit 450 is driven (executed) after the sheet M downstream of the location where the jam has occurred is transported to the stacker 328 . In addition, in the suppression canceling process of step S200, when the jam is resolved, the sheet M that is first conveyed to the stacker 328 after the jam is resolved can be placed on the stacker 328, and the suppression unit 450 Based on the detection result of the detection unit arranged at the closest position on the upstream side of the conveying path, the driving of the suppressing unit 450 is released. In other words, in the suppression canceling process in step S200, when the jam has been resolved, the suppression unit 450 detects the suppression based on the detection result of the detection unit arranged at the position closest to the suppression unit 450 and upstream of the suppression unit 450 on the conveying path. The drive of the part 450 is released. A specific description will be given below.

First, the suppression execution processing method will be described. FIG. 15 is a flow chart showing an execution processing method of the suppression unit. As shown in FIG. 15, in step S101, the paper M is conveyed. Specifically, each transport roller pair (transport roller pair 131, first to third transport roller pairs 254, 256, 257, first and second The pair of reversing rollers 265 and 268, the pair of discharge rollers 329, and the pair of transport rollers 327) are driven. Further, the recording unit 110 of the image forming apparatus 100 is driven to form an image on the transported sheet M. FIG. As a result, the paper M on which the image is formed is conveyed to the third discharge path 153 , the intermediate conveying path 218 and the downstream conveying path 319 .

Next, in step S102, it is determined whether or not a jam has occurred. Specifically, the controller 10 determines whether there is a jam on the third discharge path 153 , the intermediate transport path 218 , and the downstream transport path 319 , which are upstream of the stacker 328 . A jam is detected by each detection unit (conveyance detection unit 199, introduction detection unit 258, first to fifth detection units 281, 282, 283, 284, 285, first and second reversal detection units 264, 267 and the detection data transmitted from the transport detection unit 356). If it is determined that a jam has occurred (YES), the process proceeds to step S103, and if it is determined that a jam has not occurred (NO), the process ends (returns).

Next, when the process proceeds to step S<b>103 , it is determined whether or not there is paper M between the location where the jam occurred and the stacker 328 . Specifically, each detection unit (conveyance detection unit 199, introduction detection unit 258, first to fifth detection units 281, 282, 283, 284, 285) arranged between the location where the jam occurred and the stacker 328 , first and second reversal detection units 264 and 267, and conveyance detection unit 356). If it is determined that there is paper M (YES), the process proceeds to step S104, and if it is determined that there is no paper M (NO), the process proceeds to step S105.

Then, when the process proceeds to step S104, the stacker 328 is caused to transport the sheet M downstream of the location where the jam occurred in the transport path. That is, the paper M on the transport path between the location where the jam occurred and the stacker 328 is moved to the corresponding transport roller pairs (the transport roller pair 131, the first to third transport roller pairs 254, 256, 257, the first and the second pair of reversing rollers 265 and 268 and the pair of conveying rollers 327) are driven to convey (recover) to the stacker 328. Next, the process proceeds to step S103.

For example, when an error is detected by the transport detection unit 199 and a jam occurs in the third discharge path 153, if there is paper M in the intermediate transport path 218 or the downstream transport path 319, the corresponding transport roller pair (first , the third conveying roller pairs 254, 256, 257, the first and second reversing roller pairs 265, 268, and the conveying roller pair 327) are driven to stack the paper M on the intermediate conveying path 218 or the downstream conveying path 319 into the stacker 328. be transported to

Further, for example, in the intermediate conveying device 200, an error is detected by the introduction detection unit 258, the first detection unit 281, or the second detection unit 282, and the introduction route 243, the first branch route 244, or the second branch route 245, and the sheet M is located downstream in the transport direction from the location where the jam occurred, the corresponding transport roller pairs (second and third transport roller pairs 256, 257, first and second reversing rollers 265, 268, and transport roller pair 327) to drive the paper in the first reversing path 248, the second reversing path 249, the first merging path 246, the second merging path 247, the outlet path 250, and the downstream transport path 319. M is transported to stacker 328 .

Further, for example, in the intermediate conveying device 200, an error is detected by the first reversing detection section 264 or the second reversing detection section 267, and a jam occurs on the first reversing path 248 or the second reversing path 249, causing a jam. When the sheet M is located downstream in the transport direction from the point where The stacker 328 transports the paper M present in the second confluence path 247 , the outlet path 250 , and the downstream transport path 319 .

Further, for example, in the intermediate conveying device 200, an error is detected by the third detection section 283 or the fourth detection section 284, and a jam occurs in the first joining path 246, the second joining path 247, or the first lead-out path 250a. However, if there is paper M downstream of the location where the jam occurred, the corresponding transport roller pair (the third transport roller pair 257, the transport roller pair 327) is driven, and the output path 250 or the downstream transport path is driven. The paper M in 319 is transported to the stacker 328 .

Further, for example, in the intermediate conveying device 200, when an error is detected by the fifth detection unit 285, a jam occurs in the second lead-out path 250b, and the sheet M is located downstream in the conveying direction from the location where the jam occurred, The corresponding transport roller pair (transport roller pair 327 ) is driven to transport the paper M on the downstream transport path 319 to the stacker 328 .
The method for collecting and conveying the sheet M is an example, and the arrangement of the detection units in the conveyance path and the drive motors corresponding to the arranged detection units can be arbitrarily set.

Next, in step S105, the suppression unit 450 is driven (executed). Specifically, the gap G between the first discharge roller 329a and the second discharge roller 329b is changed to a second gap G2, which is narrower than the first gap G1, with the paper M placed on the stacker 328 interposed therebetween. variable to That is, the first discharge roller 329a is moved from the first position Ps1 to the second position Ps2. Furthermore, the distance K between the sheets M placed on the stacker 328 and the guide surface 330a is changed to a second distance K2 narrower than the first distance K1. That is, the guide portion 330 is moved from the first position Pk1 to the second position Pk2 (see FIG. 12).

As a result, the sheet M placed on the stacker 328 curls with the lapse of the standing time. , the occurrence of deformation (curling) of the paper M can be suppressed.
In addition, after the occurrence of the jam, the paper M located downstream of the location where the jam occurred is transported (recovered) to the stacker 328, and then the suppressing unit 450 is driven. can.

Next, a suppression cancellation processing method will be described. FIG. 16 is a flow chart showing a method of canceling the suppression unit.

First, to release the suppression unit 450, it is necessary to eliminate the jam. For example, the paper M causing the jam is pulled out from the transport path with fingers. This clears the jam.
Considering the processing unit of the paper M to be post-processed by the post-processing unit 325 , the paper M at the location where the jam has occurred and the paper M on the recording unit 110 or the like are taken out from the printer 1 . After that, each detection unit (conveyance detection unit 199, introduction detection unit 258, first to fifth detection units 281, 282, 283, 284, 285, first and second reversal detection units 264, 267, conveyance detection unit 356) After confirming that the error has been canceled, the printer 1 is restarted (step S201).

Next, in step S202, the sheet M to be conveyed first after the jam is cleared can be placed on the stacker 328, and the detection unit arranged at the upstream position closest to the suppression unit 450 on the conveying path. (In this embodiment, the fifth detection unit 285a arranged at the closest upstream position on the second lead-out path 250b as the transport path to the suppressing unit 450) detects whether or not the first sheet M is detected. determine whether
Specifically, for example, when the printing apparatus 1 is restarted in a state in which all the sheets M have been removed from the third discharge path 153, the intermediate transport path 218, and the downstream transport path 319, at what timing does the suppression unit 450 The problem is whether to release the drive. That is, for example, if the sheet M to be transported first is detected by the introduction detection unit 258 on the upstream side of the intermediate transport path 218 and the suppressing unit 450 is released, the first sheet M is transported to the stacker 328 . Since it takes a long time to complete the process, the deformation (curl) of the paper M placed on the stacker 328 progresses. On the other hand, if the detection unit arranged closest to the stacker 328 on the upstream side of the transport path detects the first transport of the paper M, the suppressing unit 450 will stop the paper M during the release operation. There is a risk that the sheet M will be transported to the stacker 328, causing a transport failure.

Therefore, the time until the detection of the paper M is determined and the paper M is transported to the stacker 328, and the time until the release operation of the suppression unit 450 is completed after receiving the determination from the detection result of the detection unit are Based on the detection data in the detection unit (the fifth detection unit 285a in the present embodiment) arranged at a position that satisfies the above conditions, whether or not the first conveyed sheet M after the jam has been detected. to judge. If it is determined that the paper M has been detected (YES), the process proceeds to step S203. On the other hand, if it is determined that the paper M has not been detected (NO), the process moves to step S202 again.

Next, when the process proceeds to step S203, the drive of the suppression unit 450 is released. Specifically, the gap G between the first paper discharge roller 329a and the second paper discharge roller 329b is changed from the second gap G2 to the first gap G1 through the paper M placed on the stacker 328. do.
That is, the first discharge roller 329a is moved from the second position Ps2 to the first position Ps1. Further, the distance K between the sheets M placed on the stacker 328 and the guide surface 330a is varied from the second distance K2 to the first distance K1. That is, the guide portion 330 is moved from the second position Pk2 to the first position Pk1 (see FIGS. 4 and 12).

As a result, even after the jam is cleared, it is possible to ensure the suppression time of the suppression unit 450 .
As described above, according to this embodiment, the following effects can be obtained.

When a jam occurs in the printing apparatus 1, the sheet M placed on the stacker 328 of the post-processing device 300 is held down by the suppression section 450 (paper discharge roller pair 329, guide section 330). Thereby, curling of the paper M can be suppressed. Further, when the jam is cleared, the suppression unit 450 is driven until immediately before the first sheet M conveyed after the jam is cleared is conveyed to the stacker 328 . Therefore, even if the jam is cleared and the paper M is transported to the stacker 328, the occurrence of transport problems due to curling is reduced. Then, the sheets M are arranged in an orderly manner in the stacker 328, and post-processing can be reliably performed.

It should be noted that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made to the above-described embodiment. Modifications are described below.

(Modification 1) In the above embodiment, the structure of the discharge roller pair 329 and the guide part 330 as the suppression unit 450 has been described as an example, but the structure is not limited to this. For example, the suppression unit 450 may be a blower (various fans). Then, when a jam occurs upstream of the stacker 328 in the transport path of the paper M, the air may be blown to the paper M placed on the stacker 328 . Even in this way, it is possible to easily suppress deformation such as curling of the paper M due to air pressure caused by air blowing.

(Modification 2) In the above-described embodiment, the configuration of the discharge roller pair 329 and the guide section 330 as the suppression section 450 has been described as an example, but the configuration is not limited to this. For example, the suppression unit 450 may include a moisturizing unit capable of moisturizing the sheet M placed on the stacker 328 in addition to the sheet discharge roller pair 329 and the guide unit 330 . The humidification mechanism or method of the humidification unit is not particularly limited, and for example, it may be a vaporization method in which air is blown through a filter containing water to humidify, or water is boiled with a heater and humidified using the steam. A steam system or the like may be used. When a jam occurs on the upstream side of the transport path of the paper M from the stacker 328, the paper M placed on the stacker 328 is humidified by the humidification unit while the paper ejection roller pair 329 and the guide are moved. A section 330 suppresses deformation of the sheet M. FIG. In this way, when a jam occurs, deformation of the paper M is suppressed by the suppressing unit 450 and the paper M is humidified by the humidifying unit, so curling of the paper M can be suppressed more effectively. .
When the paper M is humidified, the surface or area of the paper M is appropriately selected and humidified according to the curling state of the paper M. FIG. As a result, it is possible to suppress the curling of the paper M more efficiently.

(Modification 3) In the above embodiment, the printing apparatus 1 includes the image forming apparatus 100, the intermediate conveying apparatus 200, and the post-processing apparatus 300, but the present invention is not limited to this configuration. For example, the printing apparatus 1 includes the image forming apparatus 100 that forms an image on a medium, the stacker 328 that temporarily places the medium on which the image is formed, and the medium placed on the stacker 328 . a post-processing unit 325 that performs post-processing, and a suppressing unit 450 that suppresses deformation of the media placed on the stacker 328 . may be That is, the configuration may be such that the intermediate conveying device 200 is omitted. Further, for example, the intermediate conveying device 200 and the image forming apparatus 100 may be integrated, or the intermediate conveying device 200 and the post-processing device 300 may be integrated. Even in this manner, when a medium on which an image is formed by the image forming apparatus 100 is placed on the stacker 328, the suppressing unit 450 can suppress deformation such as curling of the medium.

(Modification 4) In the above-described embodiment, the guide portion 330 is configured to include the guide surface 330a as the contact portion, but the present invention is not limited to this. For example, it is not limited to surface contact with the paper M like the guide surface 330a, and may be configured to have projections capable of point contact with the paper M. FIG. Curling of the paper M can also be suppressed in this manner.

(Modification 5) In the above embodiment, the recording unit 110 in the image forming apparatus 100 is an example of the line head type recording head 111 capable of simultaneously ejecting ink over substantially the entire width direction of the paper M. , but not limited to this configuration. For example, it may be a serial head type printer. Further, the image forming apparatus 100 may be configured to include a transport path dedicated to single-sided printing. Even if it does in this way, the effect similar to the above can be acquired.

DESCRIPTION OF SYMBOLS 1...Printing apparatus 10...Control part 100...Image forming apparatus 101...Recording-apparatus side housing|casing 102...Operation part 103...Paper cassette 103a...Grip part 104...Front plate cover 108...Exit port, DESCRIPTION OF SYMBOLS 109... Paper discharge tray, 110... Recording part, 111... Recording head, 120... Conveyance path in apparatus, 131... Conveyance roller pair, 132... Belt conveyance part, 133... Drive roller, 134... Driven roller, 135... Belt, 140 Supply path 141 First supply path 141a Cover 141b Insertion port 142 Second supply path 142a Pickup roller 143 Third supply path 144 First drive roller pair 145 Separation Roller pair 146 Second driving roller pair 147 Branching mechanism 148 Third driving roller pair 149 Aligning roller pair 150 Ejection path 151 First ejection path 151a Curved reversal path 152 Second ejection path 153 Third ejection path 154 Common ejection path 155 Ejection port 156 Mounting table 157 Vertical side wall 160 Branch path 161 Branch path roller pair 170 Drawer unit 180... Guidance mechanism (switching guide part) 199... Conveyance detection part 200... Intermediate conveying device 218... Intermediate conveying path 218a... Pre-reversal path 218b... Post-reversal path 241... First reversing part 242... Second 2 reversing section, 243... introduction route, 244... first branch route, 245... second branch route, 246... first joining route, 247... second joining route, 248... first reversing route, 249... second reversing route , 250... lead-out path, 250a... first lead-out path, 250b... second lead-out path, 252... intermediate conveying section, 254... first conveying roller pair, 256... second conveying roller pair, 257... third conveying roller pair, 258 Introduction detector 259 Guide flap 261 First regulation flap 262 Second regulation flap 264 First reversal detector 265 First pair of reversing rollers 267 Second reversal detector 268 Second reversing roller pair 281 First detection unit 282 Second detection unit 283 Third detection unit 284 Fourth detection unit 285 Fifth detection unit 285a Fifth detection unit 300 Post-processing device 319 Downstream transport path 320 Frame 322 Post-processing paper feed port 323 Post-processing paper discharge port 325 Post-processing section 327 Conveying roller pair 328 Stacker 328a Placement surface 328b Wall surface 329 Discharge roller pair 329a First discharge roller 329b Second discharge roller 3 Reference numerals 30: guide section, 330a: guide surface, 330b: tip portion, 331: discharge tray, 331a: placement surface, 335: downstream transport section, 356: transport detection section, 450: suppression section.

Claims (14)

a stacker for temporarily placing media;
a post-processing unit that performs post-processing on a predetermined number of the media placed on the stacker;
a paper discharge tray for stacking the media discharged from the stacker;
a post-processing apparatus comprising: a suppressing unit that suppresses deformation of the media less than the predetermined number of the media placed on the stacker. In the post-processing device according to claim 1,
The post-processing device, wherein the suppressing unit suppresses deformation of the medium when a jam occurs upstream of the stacker in the transport path of the medium. In the post-processing device according to claim 1 or claim 2,
The suppression unit is
a first roller;
a second roller;
The interval in the direction in which the medium is sandwiched between the first roller and the second roller is variable between a first interval and a second interval where the interval is narrower than the first interval,
When a jam occurs on the upstream side of the medium transport path from the stacker,
A post-processing device, wherein the gap between the first roller and the second roller is changed to the second gap through the medium placed on the stacker. In the post-processing device according to claim 3,
The post-processing device, wherein the first roller and the second roller are configured to discharge the medium from the stacker to the discharge tray. In the post-processing device according to claim 4,
At the first interval, one of the first roller and the second roller is out of contact with the medium;
The post-processing device, wherein the first roller and the second roller are in contact with the medium at the second interval to suppress deformation of the medium. In the post-processing device according to claim 5,
The suppression unit is
comprising a contact portion capable of contacting the surface of the medium;
the first roller is above the second roller;
The post-processing device, wherein the contact portion rotates around the axis of the first roller and comes into contact with the medium to suppress deformation of the medium. In the post-processing device according to claim 5,
the suppressing portion includes a contact portion capable of contacting the surface of the medium;
The distance between the medium placed on the stacker and the contact portion is variable between a first distance and a second distance that is narrower than the first distance,
When a jam occurs on the upstream side of the medium transport path from the stacker,
A post-processing apparatus, wherein the distance between the media placed on the stacker and the contact portion is variable to the second distance. In the post-processing device according to claim 7,
At the first distance, the contact portion is out of contact with the medium;
The post-processing device, wherein the contact portion contacts the medium at the second interval to suppress deformation of the medium. In the post-processing device according to claim 1,
The suppression unit is a blower,
When a jam occurs on the upstream side of the medium transport path from the stacker,
A post-processing device that blows air to the media placed on the stacker. In the post-processing device according to any one of claims 2 to 9,
When the jam occurs on the upstream side of the transport path of the medium from the stacker,
The post-processing device according to claim 1, wherein the suppressing unit is driven after the media located downstream of the jammed location in the transport path are transported to the stacker. In the post-processing device according to any one of claims 2 to 10,
When the jam is resolved,
A post-processing device according to claim 1, wherein driving of the suppressing unit is canceled based on a detection result of a detecting unit arranged on the conveying path upstream of the suppressing unit and at a position closest to the suppressing unit. A control method for an aftertreatment device, comprising:
The post-treatment device is
a stacker for temporarily placing media;
a post-processing unit that performs post-processing on the media placed on the stacker;
a paper discharge tray for stacking the media discharged from the stacker;
a suppression unit that suppresses deformation of the medium placed on the stacker;
with
The control method is
placing a predetermined number of the media on the stacker;
a step of suppressing deformation of the media by the suppressing unit with respect to the media less than the predetermined number placed in the stacker;
a step of performing the post-processing by the post-processing unit on the predetermined number of the media placed on the stacker;
A control method comprising: 13. The control method according to claim 12,
In the step of suppressing deformation of the medium by the suppression unit,
When a jam occurs on the upstream side of the transport path of the medium from the stacker, after transporting the medium on the downstream side of the transport path from the location where the jam occurred to the stacker, the suppressing unit A control method for suppressing deformation of the medium. 13. The control method according to claim 12,
The step of suppressing deformation of the medium by the suppression unit includes:
a step of suppressing deformation of the medium by the suppression unit when a jam occurs upstream of the stacker in the transport path of the medium;
a step of canceling driving of the suppressing unit based on a detection result of a detecting unit disposed at a position closest to the suppressing unit and on the conveying path upstream of the suppressing unit when the jam is cleared;
A control method comprising:

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