JP5343709B2 - Sheet branching apparatus and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet branching device, an image forming device, and a method and a program for controlling the sheet branching device capable of preventing a sheet from being damaged, or preventing a printed surface of the sheet from being fouled. <P>SOLUTION: The negative pressure is generated on a platen having a fork sectional shape which has a large number of suction holes and has a horizontal part and a downward inclined part, and the sheet is conveyed in the sub-scanning direction while being sucked. When the sheet is conveyed on a branched conveying passage which is arranged in a vicinity of the downward inclined part of the platen, and has a large number of suction holes and has a horizontal part and a downward inclined part, the sheet is conveyed in the sub-scanning direction while generating the negative pressure on the branched conveying passage. When the sheet is conveyed to the downward inclined part side of the platen, generation of any negative pressure on the branched conveying passage is stopped, and the sheet is allowed to freely slide down to the downward inclined part side of the platen. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

The present invention relates to a sheet branching device and an image forming apparatus.

A copier or printer prints on different sizes of paper and then sorts them by size.
For example, as disclosed in Patent Documents 1 and 2, a method of switching the recording paper entering direction using a deflection claw is often used.
Further, as disclosed in Patent Document 3, a method of switching the recording paper conveyance direction by air suction and spraying is used.

  Specifically, in Patent Document 1, an image-formed sheet conveyed by a vertical conveying unit is deflected by a deflection claw and comes into contact with the lower surface of a tray constituting the bottom surface of the bin and enters the bin. A guide member is provided between the deflecting claw and the bin inlet to support and guide the sheet so that the approach path directed by the deflecting claw is maintained as it is. The lower surface of the tray is provided with sheet guide ribs that protrude downward and extend in the sheet entry direction. It is disclosed that the attenuation of the entrance speed of the sheet is suppressed by the guide member and the sheet guide rib.

  Japanese Patent Application Laid-Open No. 2004-228867 discloses a second paper discharge stacker disposed in a position overlapping with the paper discharge stacker in a vertical direction in a paper discharge device including a paper discharge roller for discharging paper in a predetermined direction and a paper discharge stacker. Further, it is disclosed that a pair of guide members for guiding a sheet having a predetermined width or more to a second sheet discharge stacker is provided.

  Patent Document 3 discloses a pair of guide plates provided at a recording paper branching portion in which a conveyance path is divided into a plurality of recording paper and a conveyance path is divided into a plurality of divisions in a sheet branching apparatus that determines a conveyance destination of the recording paper. An air supply / exhaust port provided in the pair of guide plates, and an air supply / discharge unit that is directly or indirectly connected to the air supply / exhaust port and applies a suction action or a spray action to the conveyed recording paper. And a conveyance path along which the recording paper travels is determined by air supply / exhaust from an air supply / exhaust port.

  As disclosed in Japanese Patent Application Laid-Open No. H10-260260, when a configuration similar to a branching claw such as a deflection claw is used as a conveyance path switching unit, an image formed on a recording sheet is not used in an inkjet image forming apparatus. There is a risk of scratching and rubbing with a deflection claw.

  Further, in the method of switching the recording paper conveyance direction by applying a suction action and a spraying action to the recording paper as disclosed in Patent Document 3, it is possible to branch without contacting the paper. is there. However, if the recording paper becomes unstable due to suction and spraying action, the paper on the upstream side (recording position) will also be affected (fluttering). To avoid flapping upstream, the trailing edge of the recording paper And the front end side must be sandwiched between a pair of transport rollers. Therefore, since ink is often not dried immediately after printing in an inkjet image forming apparatus, when this method is employed, the ink is transferred to the transport roller when the paper after recording is sandwiched between the rollers. This causes the recording paper to become dirty by retransferring it to the recording paper. Further, depending on the direction of the conveyance path along which the recording paper is branched, the printing surface may come into contact with the guide plate, which also causes problems such as recording paper contamination and image rubbing. For these reasons, it can be said that this is not suitable for an inkjet image forming apparatus.

SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet branching apparatus and an image forming apparatus that do not damage the sheet or stain the printing surface of the sheet.

To solve the above problem, according the invention of claim 1, wherein includes a the platen having a downwardly inclined portion which is disposed in the sub-scanning direction downstream side of the horizontal portion is a number of suction holes formed horizontal portion, on said platen A suction unit that sucks the sheet by generating a negative pressure on the sheet, and a conveyance unit that conveys the sheet in the sub-scanning direction by a conveyance roller that rotates in contact with the sheet from the conveyance roller opening formed on the platen. A branch conveyance path that is arranged in the middle of the downward inclined portion of the platen, has a plurality of suction holes and has a horizontal portion and a downward inclined portion, and generates a negative pressure on the branch conveyance path to Other suction means for transporting the sheet in the sub-scanning direction by another suction means for sucking, and another transport roller rotating in contact with the sheet from an opening for another transport roller formed in the branch transport path Bei and means, the A part of the plurality of suction holes of the platen is provided on the outer side in the main scanning direction, which is a descending inclined portion and can shield only a sheet whose dimension in the main scanning direction is larger than a certain value. The size in the main scanning direction is larger than a certain value by using the change in the suction amount per unit area acting on the sheet due to the change in the negative pressure due to the change in the number of suction holes shielded by the difference in the direction direction. The sheet is conveyed to the downward inclined portion side of the platen while being sucked by the suction means, and the sheet whose dimension in the main scanning direction is equal to or smaller than a predetermined value overcomes the suction force of the suction means and reaches the branch conveyance path. It is characterized by being sucked by the other suction means and transported by the other transport means .

According to a second aspect of the present invention, in the first aspect of the present invention, a sheet that is provided downstream of the platen and has a certain curvature and whose dimension in the main scanning direction is a certain value or less is separated from the suction means. A guide plate and a projection provided on the guide plate and serving as a separation assist in accordance with the size of the sheet to be separated in the main scanning direction are provided.

According to a third aspect of the present invention, there is provided printing means for performing printing by discharging ink in a main scanning direction toward the sheet at the horizontal portion of the platen, and the sheet branching device according to the first or second aspect . It is an image forming apparatus.

According to the present invention, the printing surface of the sheet is conveyed without contact with an object, and it is branched from the printing position without branching using a branching claw or requiring a conveyance path considering the ink drying time. The distance to the paper exit with the branch path can be shortened, and the recording paper is not soiled by re-transfer with the ink before drying or rubbing the print surface. it is possible to realize the provision of soiled or sheet branching device is not able to, and an image forming apparatus.

FIG. 4 is an example of a structural diagram of a sheet branching device according to the present invention used in the ink jet recording apparatus shown in FIG. 3. It is an example of the block diagram of the inkjet recording device shown in FIG. 1 is an external perspective view of an ink jet recording apparatus as an image forming apparatus using a sheet branching apparatus according to the present invention. It is an example of the top view of the platen used for the sheet branching apparatus shown in FIG. FIG. 2 is an explanatory diagram for explaining a positional relationship between the recording paper and the separation assisting member illustrated in FIG. 1. FIG. 2 is an enlarged cross-sectional view of the vicinity of a branching portion of the sheet branching device shown in FIG. 1. FIG. 3 is an example of a flowchart for discharging recording paper of the sheet branching apparatus shown in FIG. 1. FIG. FIG. 5 is an explanatory diagram for explaining a positional relationship between the recording paper illustrated in FIG. 1 and another separation assisting member.

An embodiment of the present invention will be described.
FIG. 3 is an external perspective view of an ink jet recording apparatus as an image forming apparatus using the sheet branching apparatus according to the present invention.
The ink jet recording apparatus shown in FIG. 3 is a serial type ink jet recording apparatus, and includes an apparatus main body 1 and a support base 2 that supports the recording apparatus main body 1.
Inside the recording apparatus main body 1, a guide rod 3 and a guide rail 4 are spanned on both side plates (not shown), and a carriage 5 is held on the guide rod 3 and the guide rail 4 so as to be slidable in the direction of arrow A. ing.

The carriage 5 is mounted with a liquid ejection head that ejects ink droplets of each color of black (K), yellow (Y), magenta (M), and cyan (C).
Each recording head is integrally provided with a sub tank (not shown) for supplying ink to each recording head.
The main scanning mechanism that moves and scans the carriage 5 includes a drive motor 11 disposed on one side in the main scanning direction (arrow A direction), a drive pulley 12 that is rotationally driven by the drive motor 11, and the other side in the main scanning direction. A driven pulley 13 is provided, and a belt member 14 is provided between the driving pulley 12 and the driven pulley 13.

The driven pulley 13 is tensioned outward (in a direction away from the drive pulley 12) by a tension spring (not shown).
The belt member 14 pulls the carriage 5 in the main scanning direction by being partly fixed and held by a belt fixing portion provided on the back side of the carriage 5.

An encoder sheet (not shown) for detecting the main scanning position of the carriage 5 is arranged along the main scanning direction of the carriage 5, and the encoder sheet is read by an encoder sensor (not shown) provided on the carriage 5. It is done.
Among the main scanning areas in the carriage 5, in the recording area, the paper 10 is intermittently conveyed in a direction (sub-scanning direction: arrow B direction) orthogonal to the main scanning direction of the carriage 5 by a paper feed mechanism (not shown). .

  In addition, a maintenance / recovery mechanism 8 that performs maintenance / recovery of the recording head 5 is disposed in one end side region of the main scanning region. Further, a main cartridge 9 containing each color ink to be supplied to a sub tank of the recording head 5 is located outside the carriage movement area in the main scanning direction or in the other end side area of the main scanning area with respect to the recording apparatus main body 1. And is detachably mounted.

  The ink jet recording apparatus 1 is capable of transporting a plurality of sizes of paper 10 whose sizes in the width direction are different from those of a paper feeding means (not shown). The paper 10 transported from the paper feeding means is directed from the rear to the front. Then, it is conveyed to the recording area by a conveying means (not shown). Then, by moving the carriage 5 in the main scanning direction and intermittently feeding the paper 8, the recording head 5 is driven according to the image information to eject droplets, thereby forming a required image on the paper 10. Is done. Further, the sheet 10 after the image formation passes through the first guide plate 104 as the downward inclined portion, and then the first discharge guide plate 107 or the second discharge guide according to the size in the width direction by the separation assisting member 105. It is guided to one of the plates 111 and discharged.

FIG. 2 is an example of a block diagram of the ink jet recording apparatus shown in FIG.
Reference numeral 20 denotes a central processing unit (CPU) that performs overall control of the ink jet recording apparatus, and includes, for example, a microprocessor.
Reference numeral 21 denotes a RAM (random access memory) that temporarily stores image data, operation data, processing data, and the like, for example, a flash memory.
Reference numeral 22 denotes a ROM (read only memory) that stores a control program, and includes, for example, a mask ROM.
Reference numeral 23 denotes an operation unit for a user to operate, such as an operation key, an on / off switch, a numeric keypad, and a display panel.
Reference numeral 24 denotes an I / O (in put / out put) port for inputting a control signal from the outside and outputting a recording state to the outside, for example, a USB (universal serial bus) standard connector. It is done.
113a is a first suction fan driving motor for rotationally driving the first suction fan 113, 114a is a second suction fan driving motor for rotationally driving the second suction fan 114, and for example, In either case, a DC (direct current) axial fan or an AC (alternating current) axial fan can be used.
103a is a first transport roller driving motor for rotationally driving the transport roller and the first transport roller, and 110a is a second transport roller driving motor for rotationally driving the second transport roller. Both include DC motors and DC brushless motors.
5a is a motor for moving the recording head 5 in the main scanning direction, for example, a stepping motor.
The sensors S1 and S2 are sensors for detecting the passage of the recording paper 101, and examples thereof include a transmissive photo interrupter.

Next, a sheet branching device used in the ink jet recording apparatus shown in FIG. 3 will be described.
FIG. 1 is an example of a structural diagram of a sheet branching apparatus according to the present invention used in the ink jet recording apparatus shown in FIG. FIG. 1 shows a cross section from the vicinity of the recording head 5 to the paper discharge tray.
FIG. 4 is an example of a plan view of a platen used in the sheet branching apparatus shown in FIG.
In FIG. 1, a platen 102 is disposed at a position facing the recording head 5.
The platen 102 has a fork cross-sectional shape in which a large number of suction holes are formed and has a horizontal portion and a downward inclined portion, and a plurality of suction holes as shown in FIG. 4 are provided.
An air chamber 115 covered with a wall and a first suction fan 113 that discharges air in the air chamber 115 are provided on the back side (lower side of the drawing) of the platen 102.
When the recording paper 101 as a sheet is on the horizontal portion of the platen 102, the suction action works over the entire width of the recording paper 101 due to the negative pressure generated from the first suction fan 113. When this suction action causes the first suction fan 113 to move toward the suction side, negative pressure is generated in the first air chamber 115, and suction is performed on the recording paper 101 through the suction holes 121 provided in the platen 102. Is called.
With the recording paper 101 sucked, ink is applied from the recording head 5 and an image is recorded on the upper surface of the recording paper 101 of the ink jet recording apparatus in FIG.

Until the recording paper 101 passes through the recording head 5, the recording paper 101 is nipped and conveyed by conveying means (not shown) (provided upstream of the recording head 5).
After passing through the recording head 5, the recording paper 101 is sucked toward the platen 102, and is pressed against the conveyance roller 103 (drive roller) disposed in the conveyance path formed by the platen 102.
Accordingly, the recording paper 101 is transported to the downstream transport path by the transport force generated by the suction force generated by the first suction fan 113 and the friction of the transport roller 103, so that the driven roller contacting the print surface (upper surface) or the like Transport is performed with a transport force applied without providing a member.
Note that instead of the conveyance roller 103, a conveyance belt may be used to convey the recording paper 101 by electrostatic adsorption to the conveyance belt.

  The downstream conveyance path after image formation is formed away from the platen 102 and the first paper discharge path formed by the first guide plate 104 and the first paper discharge guide plate 107 that are formed following the platen 102. The second guide plate 109 and the second discharge guide plate 111 are configured. The second guide plate (horizontal portion) 109, the second discharge guide plate 111 (inclined portion), and the second discharge tray 112 (inclined portion) constitute a branch conveyance path. The joint between the second guide plate 109 and the second paper discharge guide plate 111 has an obtuse angle in the figure, but the present invention is not limited to this and may be curved.

  As shown in FIGS. 1 and 6, the first guide plate 104 is configured as a guide plate that is integral with or continuous with the platen 102 and has a certain curvature ρ. This curvature ρ is set to a value that allows the recording paper 101 to be separated from the guide plate 104 in accordance with the stiffness (rigidity) of the recording paper 101 when the dimension of the recording paper 101 in the main scanning direction is equal to or smaller than a certain value. Is set.

  Further, as shown in FIG. 6, the first guide plate 104 has the maximum width of the recording paper passing through the second paper discharge path, and the separation assisting member 105 protruding from the surface of the first guide plate 104 is provided. Is formed.

6 is an enlarged cross-sectional view of the vicinity of the branching portion of the sheet branching apparatus shown in FIG.
Further, as shown in FIG. 5, the positional relationship between the separation assisting member 105 and the guide plate 109 is such that the vertical difference between the upper surface portion of the separation assisting member 105 and the upper surface portion of the guide plate 109 is H. When the horizontal distance between the downstream end of the separation assisting member 105 and the upstream end of the guide plate 109 is L, it is separated from the suction force and passes through the branch conveyance path to the second discharge port. H and L so that the narrow recording paper conveyed and the wide recording paper conveyed to the first paper discharge port without being separated from the suction force can pass through without being caught on the way. And set the value.

Further, the separation assisting member 105 is formed on the downward inclined portion (curved portion) of the first guide surface 104. That is, by moving from the horizontal portion of the first guide surface 104 to the curved portion, a force to return the recording paper 101 in the horizontal direction due to the stiffness of the recording paper 101 acts. Is easier.
The separation assisting member 105 is a member that acts to separate the narrow recording paper 101 from the guide plate 107, but is merely an obstacle when passing through the wide recording paper 101.

  Therefore, it is preferable to select a material having a small friction coefficient to the extent that the conveyance of the recording paper 101 is not hindered. For example, it is a POM (polyacetal resin) material, and may be another member subjected to Teflon (registered trademark) processing. Further, the downstream corner portion serving as the conveying surface is preferably formed into a shape that is rounded so as not to leave scratches or streak marks on the non-printing surface of the recording paper 101 as indicated by 400 in FIG.

  A number of suction holes are formed in the first guide plate 104 in the same manner as the platen 102, and the recording paper 101 is attracted to the first transporting roller 106 in the same manner as the transport of the recording paper 101 in the transporting roller 103. 1 Transported toward the paper discharge guide 107.

  On the other hand, the separation assisting member 105 is not provided with a suction hole and is not affected by the negative pressure from the air chamber 115.

Similar to the platen 102, the second guide plate 109 is provided with a number of suction holes, air chambers 116, a fan 114, and a second transport roller 110 (drive roller).
When the recording paper 101 reaches the second guide plate 109, the recording paper 101 is attracted to the suction hole, and the recording paper 101 is attracted to the second transport roller 110 and directed toward the second paper discharge tray 112 in the same manner as described above. Be transported.
Note that the second guide plate 109 has no suction holes formed in the region A in FIG. Therefore, from the area A toward the downstream side, the recording paper falls by its own weight (free sliding) along the inclined surfaces of the second guide plate 109 and the second paper discharge tray 112.

  Further, as shown in FIG. 5, an inclined surface 401 that is inclined downward is formed at the upstream end of the second guide plate 109. The inclined surface 401 serves to scoop up the leading edge of the recording paper 101 separated from the first guide plate 104 by the separation assisting member 105. With this action, the leading edge of the recording paper 101 can land on the second guide plate 109 more reliably.

  With the above configuration, the first paper discharge path includes A0 portrait (long side is parallel to the sub-scanning direction), A1 landscape (long side is parallel to the main scanning direction), A1 portrait, A2 landscape, and A2. A wide recording paper 101 having a size in the main scanning direction corresponding to or corresponding to the vertical, A3 horizontal is transported, and the second discharge path is A3 vertical, A4 horizontal, A4 vertical. A narrow-width recording paper 101 having a size in the main scanning direction corresponding to or equivalent to the above is conveyed.

Next, the flow of discharging the recording paper to the first paper discharge path and the second paper discharge path will be described with reference to FIG.
FIG. 7 is an example of a flowchart for discharging the recording paper of the sheet branching apparatus shown in FIG.
When the CPU 20 (see FIG. 2) receives print instruction information from the outside via the operation of the operation unit 23 or the I / O (24) (S501), the first suction is performed while the second suction fan 114 is stopped. The fan 113 (see FIG. 1) is operated, and the first transport roller driving motor 103a is driven (S502).
When the recording paper 101 is conveyed by the conveying roller 103 while being attracted to the platen 102, an image or a character is recorded on the upper surface (S503).
The recording paper 101 on which images and characters are recorded is further conveyed downstream (right side in FIG. 1) by the conveying roller 103 while being attracted to the platen 102.

  The CPU 20 determines whether or not the recording paper size is wide (S504).

a) When the CPU 20 determines that the recording sheet 101 has a wide width (longer than the separation assisting member) (S504 / Y), the recording sheet 101 moves from the first discharge guide plate 107 to the first discharge path (first discharge guide plate 107). The sheet is discharged to a path on the one discharge tray 108 side).
In this case, the recording paper 101 is a wide-width recording paper having a size in the main scanning direction that is not separated by the first guide plate 104, and a large number of suction holes are formed outside the auxiliary separation member 105. The sheet is conveyed by the first plate layer roller 106 while being sucked toward the guide plate 104 without being separated, and is guided to the first sheet discharge path.
Specifically, the CPU 20 determines whether or not the sensor S1 is ON (S505). If the sensor S1 is not ON (S505 / N), the CPU 20 waits and determines whether or not the sensor S1 is OFF. (S506).
The CPU 20 stands by when the sensor S1 is not OFF (the recording paper 101 passes the sensor S1) (S506 / N), and determines that the sensor S1 is OFF (S506 / Y). The first conveying roller driving motor 103a is stopped (S507).
Thereafter, the recording paper 101 falls by its own weight (free sliding) due to the inclination of the first guide plate 104 and the first paper discharge guide plate 107, and is stacked on the first paper discharge tray 108 and ends.

  Thus, since the second suction fan 114 does not operate, it is possible to suppress excessive power consumption.

That is, when the wide recording sheet 101 headed to the first paper discharge guide plate 107 passes over the separation assisting member 105, the range that passes over the separation assisting member 105 is temporarily separated from the guide plate. In the range of the both ends that do not pass over the separation assisting member 105, the suction action works, so that the first discharge is performed while being sucked by the first guide plate 104 without being completely separated and entering the second paper discharge path. It is conveyed to the paper guide plate 107.
Further, since the first paper discharge guide plate 107 is a guide plate that does not have an orifice hole so that the suction action does not work, the wide recording paper 101 passes through the first conveyance roller 106 and then is conveyed at the front end in the conveyance direction. By being gradually released from the suction force from the side, the paper is slid down (freely slid) by its own weight toward the first paper discharge tray 108 disposed obliquely below and discharged.

b) When the recording paper 101 is not wide When the CPU 20 determines in S504 that the recording paper is not wide (shorter than the separation assisting member) (S504 / N), the recording paper 101 is moved to the second paper discharge path (second output). 2 is discharged from the sheet discharge guide plate to the path on the second sheet discharge tray 112 side.

  Therefore, first, the CPU 20 determines whether or not the sensor S1 is turned on (S508), and when it is determined that the sensor S1 is not ON (S508 / N), the CPU 20 waits and when it is determined that the sensor S1 is turned on ( S508 / Y), the fan 114 is operated (S509).

When the narrow recording paper 101 to be transported to the second paper discharge path (branch transport path) reaches the first guide plate 104 having the curvature ρ of the first paper discharge path, the recording paper 101 is With the narrow width, the recording paper 101 with a narrow width starts to be separated from the curved surface portion of the first guide plate 104 by using the stiffness (rigidity) of the recording paper 101.
When the recording paper 101 is further conveyed while separating the curvature, the recording paper 101 reaches a separation assisting member 105 provided on the middle of the first guide plate 104 in the first paper discharge path.

As shown in FIG. 5, the size of the separation assisting member 105 in the main scanning direction is slightly inside at both ends with respect to the largest size in the main scanning direction of the recording paper 101 conveyed to the second paper discharge path. The dimension B is set so as to be a continuous shape.
The narrow recording sheet 101 that is separated from the first paper discharge path uses the separation assisting member 105 to be parallel to the position away from the platen 102 and has a height lower than the position of the separation assisting member 105. It reaches the second guide plate 109 provided in.
After the recording paper 101 arrives, the CPU 20 determines whether or not the sensor S1 is turned off (S510). When the CPU 20 determines that the sensor S1 is not turned off (S510 / N), the CPU 20 waits and the sensor S1 is turned off. If determined (S510 / Y), the fan 113 is stopped (S511).
The CPU 20 determines whether or not the sensor S2 is turned off (S512), waits if the sensor S2 is not turned off (S512 / N), and stands by if the sensor S2 is turned off (S512 / Y). Is stopped (S513).
The recording sheet 101 falls by its own weight due to the inclination of the second sheet discharge guide plate 111 (free sliding), and is stacked on the second sheet discharge tray 1112 and ends.

  Thus, by operating the second suction fan 114 in accordance with the position of the recording paper 101, it is possible to suppress the consumption of excess power.

  As described above, when the suction force is used for the recording paper conveying means in the ink jet recording apparatus, the phenomenon that the suction force acting on the recording paper is changed when the recording paper size is different is used. Since the contact is not on the surface on which the image has just been recorded, the printing surface can be soiled, and the recording paper conveyance path can be branched to sort the paper discharge.

<Modification>
Separation Auxiliary Member 105 FIG. 8 is an explanatory diagram for explaining the positional relationship between the recording paper shown in FIG. 1 and another separation auxiliary member.
Although the separation assisting member 105 has a continuous shape in FIG. 5, it is not limited to this form.
For example, as shown in FIG. 8, it may be formed of a plurality of intermittent ribs having intervals corresponding to the dimensions in the main scanning direction of various recording paper sizes conveyed to the second paper discharge path. Since the shape of the rib at this time is the same as that of FIG. 5, description is abbreviate | omitted.

<Program>
The sheet branching apparatus or the image forming apparatus according to the present invention described above may be realized by a program that causes a computer to execute processing. Examples of the computer include general-purpose computers such as a microprocessor, but the present invention is not limited to this. Therefore, as an example, a case where the present invention is realized by a program will be described below.

To transport different sized sheets to the branch path,
(1) A suction means for sucking a sheet by generating a negative pressure on a platen having a cross-sectional shape of a fork having a plurality of suction holes and having a horizontal portion and a downward inclined portion;
(2) Conveying means for conveying the sheet in the sub-scanning direction by a conveying roller that rotates in contact with the sheet from an opening for the conveying roller formed on the platen,
(3) Other suction means that sucks the sheet by generating a negative pressure on the branch conveyance path that is arranged in the vicinity of the downward inclined portion of the platen and has a plurality of suction holes and has a horizontal portion and a downward inclined portion;
(4) Other conveying means for conveying the sheet in the sub-scanning direction with another conveying roller that rotates in contact with the sheet from the opening for the other conveying roller formed in the branch conveying path,
(5) When the sheet is conveyed on the branch conveyance path, other suction means and other conveyance means are operated, and when the sheet is conveyed to the downward inclined portion side of the platen, other suction means and other conveyance are performed. Control means for controlling the means to stop,
As a program for making it function.

  Thus, the sheet branching apparatus or the image forming apparatus according to the present invention can be realized anywhere as long as there is a computer environment capable of executing the program.

<Storage medium>
Such a program may be stored in a computer-readable storage medium.
Here, examples of the storage medium include computer-readable storage media such as a CD-ROM (Compact Disc Read Only Memory), a flexible disk (FD), a CD-R (CD Recordable), and a DVD (Digital Versatile Disk). , Flash memory, RAM (Random Access Memory), ROM (Read Only Memory), semiconductor memory such as FeRAM (ferroelectric memory), and HDD (Hard Disc Drive).

<Effect>
According to the present embodiment, the conveyance path switching means is provided with a conveyance means that applies a conveyance force by attracting the non-printing surface of the recording paper to the platen side by using a suction means by a negative pressure generated on the platen. Therefore, it can be transported without touching the printing surface, and by not using a branching claw, it is possible to reduce the distance from the printing position to the paper discharge port having a branching path without requiring a transporting path that takes into account the ink drying time. In addition, it is possible to provide a sheet branching device that eliminates the need for retransfer with pre-drying ink and rubbing on the print surface, and an image forming apparatus using the same.

  According to the present embodiment, the discharge port is switched depending on the size difference of the recording paper in the main scanning direction, so that the discharged recording paper is sorted out at a constant size even when the sizes are mixed. Ease can be improved.

  According to the present embodiment, since the conveyance path is switched using the suction force, the curvature of the conveyance member, and the separation assisting member as the boundary in the main scanning direction of the recording paper, it is not necessary to provide a separate switching member. Even if a paper jam occurs, processing of the recording paper is easy, damage to the recording paper can be reduced, and the possibility of parts being damaged can be reduced.

  The above-described embodiment shows an example of a preferred embodiment of the present invention, and the present invention is not limited thereto, and various modifications can be made without departing from the scope of the invention. is there.

DESCRIPTION OF SYMBOLS 1 Apparatus main body 2 Support stand 3 Guide rod 4 Guide rail 5 Carriage 8 Maintenance recovery mechanism 9 Main cartridge 10 Recording paper 11 Drive motor 12 Drive pulley 13 Driven pulley 14 Belt member 102 Platen 103 Conveyance roller 104 1st guide plate 105 Separation auxiliary member 107 First discharge guide plate 109 Second guide plate 110 Second transport roller 111 Second discharge guide plate 112 Second discharge tray 113 First suction fan 114 Second suction fan 115, 116 Air chamber 121 Suction hole 401 Inclined surface

JP 2000-264531 A Japanese Patent No. 2969858 JP 2007-76882 A

Claims (3)

And the platen having a downwardly inclined portion which number of suction holes are formed is arranged in the sub-scanning direction downstream side of the horizontal portion and the horizontal portion,
Suction means for generating a negative pressure on the platen to suck the sheet;
Conveying means for conveying the sheet in the sub-scanning direction by a conveying roller that rotates in contact with the sheet from an opening for the conveying roller formed on the platen;
A branch conveyance path disposed in the middle of the downward inclined portion of the platen and having a plurality of suction holes and having a horizontal portion and a downward inclined portion;
Other suction means for sucking the sheet by generating a negative pressure on the branch conveyance path;
Other transport means for transporting the sheet in the sub-scanning direction by another transport roller that rotates in contact with the sheet from an opening for another transport roller formed in the branch transport path ,
A part of the plurality of suction holes of the platen is provided on the outer side in the main scanning direction, which is the descending inclined portion and can shield only a sheet having a dimension in the main scanning direction larger than a certain value, and the main scanning direction of the sheet A sheet whose dimension in the main scanning direction is larger than a certain value by utilizing a change in suction amount per unit area acting on the sheet due to a change in negative pressure due to a change in the number of suction holes shielded by different dimensions of the sheet Is conveyed to the downward inclined portion side of the platen while being sucked by the suction means, and a sheet whose dimension in the main scanning direction is equal to or smaller than a certain value overcomes the suction force of the suction means and reaches the branch conveyance path, and A sheet branching apparatus characterized by being sucked by another suction means and conveyed by the other conveyance means . A guide plate provided downstream of the platen, having a certain curvature, and separating the sheet having a dimension in the main scanning direction not more than a certain value from the suction means;
The sheet branching device according to claim 1 , further comprising: a protrusion provided on the guide plate and serving as a separation assist in accordance with a dimension in a main scanning direction of the sheet to be separated . Printing means for performing printing by discharging ink in the main scanning direction toward the sheet in the horizontal portion of the platen ;
The sheet branching device according to claim 1 or 2,
An image forming apparatus comprising:

Images