JP4793866B2 - Paper stacking apparatus and image forming apparatus - Google Patents

Description

The present invention relates to a sheet stacking apparatus and an image forming apparatus, and more particularly to a sheet stacking apparatus attached to an image forming apparatus that records an image on a sheet by an inkjet method, and an image forming apparatus to which the sheet stacking apparatus is mounted.

As is well known, in an image forming apparatus represented by a printer, a copier, a facsimile machine, or a complex machine thereof, an image is recorded on a sheet (recording medium) such as plain paper or an OHP (Over Head Projector) film. The paper is discharged from the paper outlet. In order to discharge the sheet to the sheet discharge port, a sheet conveying device using a nip pressure like a rubber roller pair is used.

Further, an image forming apparatus that records an image while conveying a sheet at a high speed, particularly a large image forming apparatus, is used with an apparatus such as a sheet pre-processing apparatus or a sheet post-processing apparatus. The sheet post-processing apparatus includes a sheet stacking apparatus that receives the image-recorded sheet sent from the sheet discharge port of the image forming apparatus and loads the sheet on a discharge sheet receiver such as a lifting tray. The paper stacking device also incorporates a paper transport device using nip pressure like a rubber roller pair.

Among conventional image forming apparatuses, an image forming apparatus that records an image on a sheet by a so-called inkjet method uses an ink jet print head so that good printing is possible in the entire area without being limited by the print area of the sheet. 2. Description of the Related Art There is known a technique for providing a sheet adsorbing unit that adsorbs a sheet passing through at least a position immediately below (inkjet head) to a sheet conveying surface. For example, Patent Document 1 discloses a paper suction unit that includes a suction box that constitutes a paper transport surface and a suction fan that is rotated by a suction motor, and a plurality of suction holes are provided on the upper surface of the suction box. Is disclosed. In other words, a conventional paper transport device including a paper suction unit reduces the pressure in the suction box by rotating a suction fan using a suction motor, and sucks air above the top surface of the transport belt from the suction box. Is adsorbed to the traveling belt and conveyed.

Also, in a paper stacking device that uses paper discharge means that uses nip pressure such as a pair of rubber rollers, it is used by being attached to an image forming apparatus that records an image on paper by an inkjet method, particularly a high-speed image forming apparatus. In order to prevent undried ink on the image-recorded paper sent from the paper discharge port from adhering to the paper discharge means and causing image distortion, a paper suction means for sucking the paper to the traveling belt is provided. A sheet transport device provided is generally used.
JP 2002-103705 A (FIG. 4, paragraph 0048)

However, in the conventional paper stacking device, since the suction fan of the paper suction means in the paper transport device is always driven, there is a problem that it is inevitable that a large amount of power is consumed.

The first object of the present invention is the distance from the sheet discharge unit of the image forming apparatus to the sheet discharge unit of the sheet stacking apparatus, in which the length of the image-recorded sheet sent from the image forming apparatus is in the sheet conveyance direction. Note that when the length is longer than the predetermined length, either the front edge or the rear edge of the paper is always nip-conveyed by the paper discharge means, and there is no need to suck the paper by the paper suction means. In such a case, it is an object to provide a paper stacking device that reduces power consumption by stopping the paper suction means.

A second object of the present invention is to provide a paper stacking device in which a receiving lift means that moves up and down in accordance with the stack height of discharged paper is provided on the discharged paper receiver.

A third object of the present invention is to form a traveling belt by a plurality of belts arranged along the sheet conveying direction, and drive the plurality of traveling belts by a common belt driving means, thereby providing a plurality of locations on the lower surface of the sheet. It is an object of the present invention to provide a paper stacking device that reliably conveys paper by a synchronized rotation of a plurality of traveling belts that are in surface contact with each other.

A fourth object of the present invention is to receive an image-recorded sheet sent out from the image forming apparatus and suck it onto the traveling belt without slipping by a simple sheet adsorbing means using air, and integrally with the traveling belt. An object of the present invention is to provide a paper stacking device that reliably transports paper.

A fifth object of the present invention is to receive an image-recorded sheet sent out from an image forming apparatus and suck it onto a traveling belt without slipping by a simple sheet adsorbing means using static electricity. An object of the present invention is to provide a paper stacking device that reliably transports paper.

A sixth object of the present invention is to provide an image forming apparatus to which a paper stacking device that reduces power consumption by stopping paper suction means according to the paper size is attached.

Means for Solving the Problems and Effects of the Invention

Sheet stacking device as claimed in around 1 includes a belt conveying means for conveying the image recorded sheet fed Riga image recording by the ink jet method rows planted image forming apparatus, put on the running belt, wherein arranged downstream of the belt conveying unit, a paper discharge means for discharging the Nitsupu convey the sheet conveyed by placing the running belt, discharged paper stacking receiving the sheet discharged by said sheet discharge means A paper stacking device having a receiver and a control means for controlling the operation of the belt conveying means, the paper discharging means, and the discharged paper receiver ,
The belt conveying unit includes a sheet adsorbing unit that adsorbs the sheet being conveyed by the traveling belt when operating, and rejects the sheet when stopped, and the control unit has a length of the sheet in the sheet conveying direction. When the predetermined distance L from the paper discharge roller of the image forming apparatus to the paper discharge means of the paper stacking apparatus is longer than the predetermined distance L , the operation of the paper suction means is stopped and the transport speed of the paper discharge means is increased. The sheet discharge means increases the conveyance speed of the sheet being conveyed on the traveling belt, and the conveyance speed is increased near the rear end of the sheet. The sheet is decelerated and loaded on the discharge receiver .
Oite the sheet stacking equipment according to claim around 1, it is possible to reduce power consumption by stopping the sheet suction means in accordance with the size of the paper. Specifically, the distance (predetermined length) L from the position of the sheet discharge unit of the image forming apparatus to the sheet discharge unit of the sheet stacking apparatus is set to be shorter than the maximum usable sheet length of the image forming apparatus. For example, if the distance L is set to be 364 mm or less for a B4 size paper, when conveying a paper of a B4 size or longer, at least one of the paper discharge means of the image forming apparatus or the paper discharge means of the paper stacking apparatus. Since the sheet can be conveyed by one side, the sheet can be conveyed even if the sheet adsorbing unit of the sheet conveying apparatus is stopped, and the power consumption can be reduced by stopping the sheet adsorbing unit of the sheet conveying apparatus.

The paper stacking apparatus according to claim 2 is characterized in that in the paper stacking apparatus according to claim 1, the paper discharge paper receiver has a receiving lift unit that moves up and down in accordance with the stack height of the paper discharge. . According to the sheet stacking apparatus of the second aspect, the discharged sheets can be stacked in a properly aligned manner by moving the discharged sheet receiver up and down in accordance with the stack height of the discharged sheets.

The sheet stacking apparatus according to claim 3 is the sheet stacking apparatus according to claim 1 or 2, wherein the belt conveying unit includes a plurality of traveling belts arranged along a sheet conveying direction, and the plurality of traveling belts. Are driven by a common belt driving means. According to the paper stacking apparatus of the third aspect, the running belt is constituted by a plurality of belts arranged along the paper conveyance direction, and the plurality of running belts are driven by the common belt driving means. The paper can be reliably conveyed by the synchronized rotation of the plurality of running belts in surface contact with the plurality of locations.

The paper stacking device according to claim 4 is the paper stacking device according to any one of claims 1 to 3, wherein the paper stacking device includes an air suction unit that sucks the paper onto the traveling belt by air. It is characterized by that. According to the paper stacking apparatus of the fourth aspect, since the image-recorded paper sent out from the image forming apparatus is received and sucked onto the traveling belt without slipping by a simple paper suction means using air. Can be reliably conveyed integrally with the traveling belt.

The sheet stacking apparatus according to claim 5 is the sheet stacking apparatus according to any one of claims 1 to 3, wherein the sheet adsorbing unit electrostatically adsorbs the sheet to the traveling belt. Means are provided. According to the paper stacking apparatus of claim 5, since the image-recorded paper sent out from the image forming apparatus is received and sucked onto the traveling belt without slipping by a simple paper suction means using static electricity. Can be reliably conveyed integrally with the traveling belt.

An image forming apparatus according to a sixth aspect is characterized in that the paper stacking apparatus according to any one of the first to fifth aspects is attached to a paper discharge port position. According to the image forming apparatus of claim 6, the sheet is received by an ink jet method while receiving the sheet, mounting the sheet stacking device that reliably stacks the sheet on the discharged sheet receiver, and transporting the sheet at high speed. In addition, a low power consumption image forming apparatus for recording an image can be provided.

The object of reducing the power consumption of the paper stacking device that transports the paper by the paper transport device having the paper suction means is achieved by stopping the drive of the paper suction means according to the size of the paper.

The best mode for carrying out the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic configuration of a main part of an image forming apparatus 100 to which a paper stacking apparatus 200 according to Embodiment 1 of the present invention is attached. In FIG. 1, reference numeral 100 denotes an image forming apparatus that records an image on paper p such as plain paper or OHP film by an inkjet method while being conveyed at high speed, and reference numeral 200 denotes a paper attached to the image forming apparatus 100. It is a loading device.

The image forming apparatus 100 is a so-called ink jet printer, and the image forming unit 10 has a belt conveying means 13 formed by a conveying belt 12 being hung between a plurality of rollers 11 and 11, and a fan 14 for example. A sheet adsorbing unit 15 that generates wind in the direction a and an inkjet head 16 that selectively ejects ink from a plurality of nozzles are provided. The image forming apparatus 100 is placed on the installation surface via the casters 17 and can be moved as needed.

The image forming apparatus 100 receives a print signal from a host device (not shown), feeds the paper p from a paper storage cassette (not shown) and sends it to the image forming unit 10, and the transport belt of the belt transport unit 13. Then, the sheet adsorbing means 15 sucks air and adsorbs the sheet p onto the transport belt 12. The paper p is transported in the direction indicated by arrow b along with the travel of the transport belt 12 as the rollers 11 and 11 rotate, and at the same time, characters, figures, etc. are applied to the transported paper p by ejecting ink from the nozzles of the inkjet head 16. Record an image. The image-recorded paper p is sent out from the paper discharge port 19 to the paper stacking apparatus 200 by the paper discharge rollers 18 and 18.

The paper stacking apparatus 200 is supported by a stand 21 with a caster 20 and is attached at a height position of the paper discharge port 19 of the image forming apparatus 100. The stand 21 is placed on the installation surface via the caster 20, and an image is obtained. Similar to the forming apparatus 100, it can be moved as needed.

FIG. 2 shows an overall schematic configuration of the internal mechanism of the paper stacking apparatus 200. As shown in FIG. 2, the paper stacking apparatus 200 receives the paper p with the image recorded sent from the image forming apparatus 100 and transports it, and discharges the paper p by increasing the transport speed by nip transport. Paper discharge means B to be discharged, discharge paper receiver C for receiving the paper p discharged by the paper discharge means B and stacking the discharge paper p, and shifting the discharge paper receiver C in a direction perpendicular to the paper discharge direction to discharge paper p The paper sorting means D for sorting the paper and the receiving elevating means E for moving the discharged paper receiver C up and down according to the stacking height of the discharged paper p on the discharged paper receiver C are configured.

3 and 4 are a side view and a plan view showing a schematic configuration of the sheet conveying apparatus A. FIG. As shown in FIGS. 3 and 4, the sheet conveying apparatus A receives the image-recorded sheet p delivered from the image forming apparatus 100 and places it on the two running belts 23, 23 with the image surface facing upward. A belt conveying means 24 for carrying the paper and a paper adsorbing means 25 for adsorbing the image-recorded paper p onto the running belts 23 and 23 are configured.

The belt conveying means 24 is provided in a sheet stacking apparatus 200 and provided in a rectangular parallelepiped casing 26 that is long in the sheet conveying direction d. The housing 26 has an upper surface formed by a guide plate 27 that guides the paper p. The guide plate 27 has a suction opening 28 that is elongated in the paper transport direction d, and a square roller opening 29 that is opened before and after the paper transport direction d. 29 are arranged in series and drilled in two rows parallel to the left and right.

In the housing 26, the drive roller shaft 30 and the driven roller shaft 31 are rotatably spanned in the direction orthogonal to the paper transport direction d before and after the paper transport direction d. Then, the driving rollers 32 and 32 and the driven rollers 33 and 33 on both roller shafts 30 and 31 are respectively exposed to the outside from the front and rear and right and left roller openings 29, and the corresponding driving rollers 32 and 32 and the driven rollers 33 and 33 are corresponded. The endless running belts 23 and 23 are wound around the belts so as to cover the suction openings 28 and 28, respectively. A plurality of air holes 34 are formed in the running belts 23 and 23.

A transport motor 35 is installed in the housing 26. The rotation of the conveyance motor 35 is transmitted to the drive roller shaft 30 via an endless transmission belt 36. Then, the driving rollers 32 and 32 are rotated by the transport motor 35 to drive the traveling belts 23 and 23 while the driven rollers 33 and 33 are driven to rotate, and the image-recorded paper p sent from the image forming apparatus 100 is received. Then, it is placed on the traveling belts 23 and 23 with the image surface facing upward, and is conveyed while being guided by the guide plate 27 as the traveling belts 23 and 23 travel.

On the other hand, as shown in FIG. 3, the sheet adsorbing means 25 includes an air adsorbing means, and a fan 37 is provided to generate an air flow in the arrow direction e by the rotation of the fan 37. Air is sucked through holes (not shown), the air holes 34 of the running belts 23 and 23, and the suction openings 28 and 28 of the guide plate 27, and the paper p on which an image has been recorded is adsorbed to the running belts 23 and 23 by air.

Note that the traveling speeds of the traveling belts 23 and 23 of the belt conveying unit 24 are substantially the same as the sheet conveying speed of the image forming apparatus 100. As a result, the traveling speed of the traveling belts 23 and 23 in the sheet stacking apparatus 200 does not disturb the sheet conveying speed at the position of the ink jet head 16 of the image forming apparatus 100, and the sheet p is held on the sheet p while maintaining the constant speed conveyance. A reduction in image quality can be prevented.

In FIG. 4, reference numeral 38 denotes conveyance detection means such as a non-contact reflection type photosensor that detects the running state of the paper p guided and conveyed by the guide plate 27, and is between the suction openings 28 and 28. It is provided between the driving roller shaft 30 and the driven roller shaft 31.

As shown in FIG. 2, a paper discharge unit B is provided downstream of the paper transport apparatus A in the paper transport direction d. The paper discharge means B includes a drive discharge roller 40, a driven discharge roller 41 pressed against the drive discharge roller 40 by a spring (not shown), and a discharge motor that transmits rotation to the drive discharge roller 40 via an endless transmission belt 42. 43.

The paper discharge means B transmits the rotation of the discharge motor 43 to the drive discharge roller 40 via the transmission belt 42, rotates the drive discharge roller 40 while the driven discharge roller 41 is driven to rotate, and is driven by the drive discharge roller 40. The sheet p conveyed by the sheet conveying apparatus A is discharged onto the discharged sheet receiver C by nip conveyance with the discharge roller 41.

By the way, the paper stacking apparatus 200 includes paper detection means 44 such as a reflection type photo sensor at the upstream position of both the discharge rollers 40 and 41 to detect the paper p passing therethrough. Based on the detection result of the paper detection means 44, the CPU (Central Processing Unit) 45 (see FIG. 11), which will be described later, accelerates the leading edge of one sheet p by the paper discharge means B, and the trailing edge. Decelerate and transport. That is, the nip conveyance of both the discharge rollers 40 and 41 of the paper discharge means B is surely accelerated without slipping, the stack is not disturbed, and the conveyance speed is increased to widen the front and rear intervals of the discharged paper p. The drive time of the paper sorting means D and the receiving elevating means E is secured, and the paper p is sorted and stacked on the discharged paper receiver C with high quality. Further, by decelerating and transporting the rear end of the paper p, when discharging the paper p, the speed does not remain increased but is reduced by a fraction of the increased speed to slightly reduce the speed, and the discharged paper p is gaining momentum. To prevent the paper from popping out from the discharged paper tray C.

FIG. 5 shows a distance L (predetermined length) from the position of the paper discharge rollers 18 and 18 (paper discharge means) of the image forming apparatus 100 to the paper discharge means B of the paper stacking apparatus 200. This distance L is set to be shorter than the maximum length of usable paper of the image forming apparatus 100. For example, if the distance L is set to be 364 mm or less for the B4 size paper p, at least the paper discharge rollers 18 and 18 of the image forming apparatus 100 or the paper stacking device 200 is used when transporting the paper p having a length of B4 size or more. Since the paper p can be transported by either one of the paper discharge means B, the paper p can be transported even if the paper suction means 25 of the paper transport apparatus A is stopped.

FIG. 6 shows the paper sorting means D. The paper sorting means D includes a shift motor 50 that can rotate forward and reverse, a timing belt 51 that transmits rotation of the shift motor 50, a worm 52 that transmits rotation via the timing belt 51, and a worm wheel that meshes with the worm 52. 53, a rotation detecting plate 54 provided coaxially with the worm wheel 53, a slit detecting means 56 such as a photo interrupter for detecting the slit 55 of the rotation detecting plate 54 (see FIG. 11), and an eccentric position of the worm wheel 53. It includes a pin 57 and an end fence 60 to which a member 59 having a long hole 58 that is long in the vertical direction with which the pin 57 engages is attached. The end fence 60 is provided with an elevating tray 62 serving as a discharge sheet receiver C. The back surface of the end fence 60 (as viewed in FIG. 6) is a matching surface.

The paper sorting means D rotates the worm wheel 53 with the shift motor 50 and shifts the lifting tray 62 together with the end fence 60 in the left-right direction indicated by the arrow f. Accordingly, the lifting tray 62 is reciprocated left and right by one rotation of the worm wheel 53, and the lifting and lowering tray 62 is appropriately positioned separately at the position where the slit detecting unit 56 detects the slit 55, thereby discharging the tray. The paper p is sorted.

FIG. 7 shows a receiving elevating means E that elevates and lowers the elevating tray 62 that is the discharged paper receiver C, and a receiving position detecting means F that detects the home position of the elevating tray 62.

The receiving elevating means E transmits the rotation of the elevating motor 64 capable of rotating in the forward and reverse directions to the shaft 67 through the meshing of the gears 65 and 66, and the first pulleys 68 and 68 fixed to both ends of the shaft 67 and above each of the first pulleys 68 and 68. The lifting belts 70 and 70 are provided so as to be hung up and down between the provided second pulleys 69 and 69 in a synchronized manner. The lifting belts 70, 70 provided in parallel with each other on both sides in the paper stacking apparatus 200 fix both sides of the lifting tray 62 and move the lifting tray 62 in the vertical direction indicated by the arrow g.

The receiving position detection means F includes a horizontal rotation shaft 72 that is rotatably supported, a lever 73 that extends from the rotation shaft 72 toward the lifting tray 62, a filler 74 that extends from one end of the rotation shaft 72, It includes a position detecting means 75 such as a photo interrupter that is turned on and off by a filler 74. The receiving position detection means F pushes up the tip of the lever 73 with the raising / lowering tray 62 and the paper p stacked on the raising / lowering tray 62, and rotates the filler 74 around the rotation shaft 72. When the leading end of the sheet enters the position detecting means 75, it is detected that the elevating tray 62 has reached an appropriate position for receiving the discharged paper p. Thereafter, every time one or several sheets of paper p are discharged onto the lifting tray 62, the lifting tray 62 is once lowered and then raised, and the raised position is detected by the position detecting means 75 and stopped.

FIG. 8 shows the paper aligning means G in an exploded manner. The sheet alignment means G is provided with a holding member 80. The holding member 80 is formed with shaft portions 81, 81 protruding left and right. Sponge reverse rollers 82 and 82 are rotatably attached to the shafts 81 and 81 as sheet alignment members from the left and right, respectively. The reverse rollers 82, 82 have gear portions 83, 83 that are integral with the core metal and coaxially, and are prevented from coming off by the silencers 84, 84. The gear portions 83 and 83 mesh with intermediate gears 85 and 85 that are rotatably held by the holding member 80. Then, a part of the holding member 80 is fitted on the outer periphery of the roller shaft 86 of the drive discharge roller 40 constituting the paper discharge means B described above, and the holding member 80 is pivoted around the roller shaft 86 while being intermediate. The gears 85 and 85 are meshed with transmission gears 87 and 87 that fix the roller shaft 86 on the roller shaft 86. Accordingly, the paper alignment means G is provided so as to hang from the roller shaft 86 of the drive discharge roller 40, while the rotation of the drive discharge roller 40 is transferred from the transmission gears 87, 87 to the gear portions 83, 83 via the intermediate gears 85, 85. Then, the reverse rollers 82 and 82 are rotated. That is, the paper aligning means G is driven in conjunction with the paper discharging means B.

FIG. 9 shows a state where the sheets p are stacked on the lifting tray 62 while being aligned by the sheet aligning means G. The paper p is discharged from the paper discharge means B onto the lift tray 62, but the paper p discharged from the paper discharge means B falls on the oblique lift tray 62 by its own weight. Then, it is scratched by the reverse rollers 82, 82 by the rotation of the reverse rollers 82, 82, abuts against the end fence 60 which is the alignment surface, aligned with the rear ends aligned, and sequentially stacked as shown in the figure. Then, as the stacking height of the paper p on the lift tray 62 increases, the lift tray 62 is raised and lowered by the receiving lift means E, from the paper discharge position of the paper discharge means B to the surface of the uppermost paper p on the lift tray 62. So that the stacking property of the stacked paper p is not impaired. When the raising / lowering tray 62 reaches the lowest position, it is detected by a receiving lower limit detecting means 76 (see FIG. 11) such as a photo ink raptor, and the discharge of further sheets p is stopped. Thereafter, when the paper p on the lift tray 62 is removed, the lift tray 62 is raised to receive the next discharged paper p, and is detected by the receiving position detection means F and stopped at the uppermost position. Further, when stacking sheets p on the lifting tray 62, the sheet sorting means D shifts the lifting tray 62 in a direction f perpendicular to the sheet transport direction d as necessary to alternately stack the stacked sheets p for each copy. Sort. As a result, the image-recorded paper p sent from the image forming apparatus 100 is received and discharged by the paper discharge means B, and the discharged paper p is sorted by the paper sorting means D, and the paper is ejected on the lifting tray 62 which is the discharge paper receiver C. Can be loaded.

Although the reverse rollers 82 and 82 are used as the sheet aligning means G, a known reverse belt can be used instead of the reverse rollers 82 and 82.

FIG. 10 shows a modification of the sheet aligning means G using a reverse belt in place of gear engagement by transmission gears 87 and 87, intermediate gears 85 and 85, and gear portions 83 and 83 as rotation transmission to the reverse rollers 82 and 82. An example is shown. As shown in FIG. 10, the rotation of the roller shaft 86 of the drive discharge roller 40 is transmitted to the reverse rollers 82 and 82 via the timing belt 89. Similarly, the sheet aligning means G is provided so as to hang from the roller shaft 86 of the drive discharge roller 40, and a part of the reverse belt protrudes on the lifting tray 62, and the sheet p discharged on the lifting tray 62 is run. The paper p is scraped with a reverse belt and abutted against the end fence 60 which is the alignment surface, and the rear ends are aligned to align the paper p.

FIG. 11 shows an electrical configuration of the paper stacking apparatus 200. The paper stacking apparatus 200 includes a main control plate 90 that controls the whole. The main control plate 90 is provided with a CPU 45 made of a microcomputer as control means. The CPU 45 includes a conveyance detecting unit 38 of the sheet conveying apparatus A, a sheet detecting unit 44 of the sheet discharging unit B, a slit detecting unit 56 of the sheet sorting unit D, a position detecting unit 75 of the receiving position detecting unit F, and a receiving unit. The receiving lower limit detecting means 76 of the raising / lowering means E is connected.

Further, the CPU 45 includes a transport motor 35 of the paper transport apparatus A via the forward / reverse driver 91, a discharge motor 43 of the paper discharge means B via the forward / reverse driver 92, and a paper sorting unit via the forward / reverse driver 93. The shift motor 50 of D, the lift motor 64 of the receiving lift means E via the forward / reverse driver 94, and the fan motor 39 that drives the fan 37 of the paper suction means 25 are connected via the driver 95.

Further, a ROM (Read Only Memory) 96 for storing a program is connected to the CPU 45, and in addition, the CPU 45 is also electrically connected to a control unit 97 of the image forming apparatus 100 via an I / F (Interface) cable 98. As a result, the power of the sheet stacking apparatus 200 is obtained from the image forming apparatus 100, and sheet conveyance information such as sheet conveyance speed, sheet size, sorting unnecessary, sheet p feeding timing, sheet interval, and the like is obtained.

FIG. 12 shows an operation flowchart of the sheet stacking apparatus 200.

Next, the operation of the sheet stacking apparatus 100 according to the first embodiment configured as described above will be described in detail with reference to the flowchart shown in FIG.

When the paper stacking apparatus 200 is turned on, the CPU 45 performs initial communication with the image forming apparatus 100 (S101) and waits for the paper stacking apparatus 100 to start passing paper (S102: NO). When paper passing is started in the paper stacking apparatus 100 (S102: YES), the CPU 45 obtains the paper transporting information such as the paper transport speed V and the paper size as the paper passing paper information from the image forming apparatus 100 (S103). .

At this time, if the size of the paper p in the paper conveyance direction d is smaller than the predetermined length L which is the distance in FIG. 5 (S104: YES), the CPU 45 drives the fan motor 39 (S106), and the predetermined length L If larger (S104: YES), the fan motor 39 is not driven (S105). As described above, when the size of the sheet p in the sheet conveyance direction d is larger than the predetermined length L, either the front end or the rear end of the sheet p is always the discharge rollers 18 and 18 of the image forming apparatus 100 or the sheet stacking. The paper is ejected by the paper ejecting means B of the apparatus 200, and it is not necessary to suck the paper by the paper sucking means 25. Therefore, the power consumption is reduced by stopping the paper sucking means 25. .

Next, the CPU 45 drives the carry motor 35 and the discharge motor 43 at the paper carry speed V (S107), and then determines whether or not the paper feed is completed (S108). If it is not the end of paper passing (S108: NO), the CPU 45 obtains information such as paper size and whether or not there is a sorting request as paper passing paper information from the image forming apparatus 100 again (S109), and then the paper from the image forming apparatus 100. p is accepted (S111).

Subsequently, the CPU 45 determines whether or not the leading edge of the sheet p conveyed by the sheet conveying apparatus A is detected by the sheet detecting means 44 (S112), and detects the leading edge of the sheet p by the sheet detecting means 44 (S112). : YES), time measurement is started (or the number of pulses is confirmed) (S113), and waiting for a predetermined time to elapse (S114: NO). When the predetermined time has elapsed (S114: YES), the CPU 45 increases the speed of the discharge motor 43 to the speed V1 (V1> V) to increase the speed of the leading edge of the paper p and carry (through-up execution) (S115). Time measurement is started (or the number of pulses is confirmed) (S116), and waiting for a predetermined time to elapse (S117: NO).

When the predetermined time has elapsed (S117: YES), the CPU 45, on the contrary, decelerates the discharge motor 43 to the speed V2 (V2 <V) and decelerates and conveys the trailing edge of the paper p (S118) to measure time. Is started (or the number of pulses is confirmed) (S119), and waiting for a predetermined time to complete the paper discharge (S120: NO). By decelerating and transporting the trailing edge of the paper p, the speed is not increased at the time of discharge, but the speed V2 is reduced by a fraction of the increased speed, and the discharged paper p is momentarily received. Jumping out of the lifting tray 62, which is C, is prevented. When the predetermined time has elapsed (S120: YES), the CPU 45 returns the discharge motor 43 to the initial paper transport speed V (S121).

Next, the CPU 45 determines whether or not there is a sorting request (S122). When there is no sorting request (S122: NO), every time two sheets p are continuously discharged onto the lifting tray 62 (S123). : YES), the height of the elevating tray 62 is adjusted by the receiving elevating means E. That is, when two sheets of paper p are continuously discharged onto the lifting tray 62 (S123: YES), the CPU 45 drives the lifting motor 64 to lower the lifting tray 62 (S124), and the position detecting means 75 When turned off (S125: YES), the lifting motor 64 is reversely driven to raise the lifting tray 62 (S126). When the position detecting means 75 is turned on (S127: YES), the lifting motor 64 is turned off. Then (S128), the lifting tray 62 is stopped.

On the other hand, when there is a sorting request (S122: YES), the CPU 45 turns on the shift motor 50 to start shifting the lifting tray 62 (S129), and when the slit detecting means 56 changes from on to off (S130). : YES), the shift motor 50 is turned off and the shift of the lifting tray 62 is stopped (S131). As a result, the sheets p are stacked on the lifting tray 62 separately for each copy.

Then, the CPU 45 turns off the transport motor 35, the discharge motor 43, and the fan motor 39 (S110) when the sheet passing is completed (S108: YES).

When the drive control of the paper sorting means D and the drive control of the receiving elevating means E happen to overlap, if the drive control of the paper sorting means D is prioritized, the paper p before and after being discharged at high speed is used. Within the limited discharge time, priority is given only to the drive control of the paper sorting means D, and the drive control of the receiving elevating means E, which is not a problem even if it is not carried out once, is canceled. Thus, stackability can be improved while maintaining high productivity.

Further, even in an ink jet type image forming apparatus that performs an increase / decrease control of the discharge motor and records an image on the paper p while being conveyed at high speed, the paper discharge means B is not disturbed in the image recording at the position of the ink jet head 16. When the sheet p is discharged by increasing the transport speed of the sheet p and increasing the interval before and after the discharged sheet p to secure the drive time of the sheet sorting means D and the receiving elevating means E, the lifting tray 62 The shift and lift are completely finished, and the paper p is sorted and stacked on the lift tray 62, which is the discharged paper receiver C, with high quality.

In the first embodiment described above, the air suction means having the fan 37 is provided as the paper suction means 25. However, although not shown, an electrostatic generator is provided to feed the paper p on which the image has been recorded to the running belt 23, An electrostatic adsorption means for electrostatically adsorbing on the belt 23 is provided, and the received paper p is adsorbed onto the running belts 23, 23 by a simple paper adsorption means 25. , 23 can be reliably transported without slipping.

In the above embodiment, the apparatus (previous apparatus) on which the paper stacking apparatus 100 is mounted is described as the image forming apparatus 200. However, the previous apparatus is not limited to the image forming apparatus 200. Needless to say, it may be another device that passes the paper, such as a processing device or a paper post-processing device.

As mentioned above, although the Example of this invention was described, these are only illustrations to the last, and this invention is not limited to these, Based on the knowledge of those skilled in the art, unless it deviates from the meaning of a Claim Various changes are possible.

1 is a schematic configuration diagram of a main part of an image forming apparatus equipped with a paper stacking apparatus according to a first embodiment of the invention. 1 is an overall schematic configuration diagram of an internal mechanism of a paper stacking apparatus. FIG. 3 is a side view illustrating a schematic configuration of a sheet feeding apparatus provided in the sheet stacking apparatus. The top view of the belt conveyance means with which a paper conveying apparatus is equipped. FIG. 2 is an explanatory diagram illustrating a distance from a sheet discharge roller position of the image forming apparatus of FIG. 1 to a sheet discharge unit of a sheet stacking apparatus. FIG. 3 is a perspective view illustrating a paper sorting unit included in the paper stacking device. FIG. 3 is a perspective view showing a receiving lifting / lowering means and a receiving position detecting means included in the paper stacking apparatus. The exploded view of the paper alignment means with which a paper stacking apparatus is equipped. The perspective view which shows the state which loaded the paper on the raising / lowering tray, aligning with a paper alignment means. The block diagram which shows the modification of a paper alignment means. FIG. 3 is a block diagram illustrating an electrical configuration of the paper stacking apparatus. 6 is a flowchart showing the operation of the paper stacking apparatus.

Explanation of symbols

16 Inkjet head 18 Paper discharge roller 19 Paper discharge port 23 Travel belt 24 Belt transport means 25 Paper suction means 37 Fan 44 Paper detection means 46 CPU (control means)
60 End fence (alignment surface)
DESCRIPTION OF SYMBOLS 100 Image forming apparatus 200 Paper stacking apparatus A Paper conveying apparatus B Paper discharge means C Discharged paper receiver D Paper sorting means d Paper discharge direction E Receiving elevating means F Receiving position detecting means G Paper aligning means L Paper discharging means from the discharge roller position Distance (predetermined length)
p paper

Claims (6)

A belt conveying means for conveying the trigger image recording by the ink jet system the image recorded sheet fed from the row planted image forming apparatus, put on the running belt,
A paper discharge means disposed at a subsequent stage of the belt conveying means and for discharging the paper carried on the traveling belt by nip conveyance;
A discharge sheet receiving for stacking receiving the sheet discharged by said sheet discharge means,
Control means for controlling the operation of the belt conveying means, the paper discharging means, and the discharged paper receiver ;
A paper stacking apparatus comprising :
The belt conveying unit includes a sheet adsorbing unit that adsorbs the sheet being conveyed by the traveling belt when operating, and rejects the sheet when stopped .
Wherein, the length of the sheet conveying direction of the paper, when the paper discharge rollers of the image forming apparatus to a predetermined longer than the distance L to the sheet discharge unit of the sheet stacking apparatus, the sheet adsorption The operation of the means is stopped, the conveyance speed of the paper discharge means is made to coincide with the conveyance speed of the paper discharge roller of the image forming apparatus, and
The sheet discharge means increases the conveyance speed of the sheet being conveyed on the running belt, and decelerates the conveyance speed near the rear end of the sheet to load the sheet on the discharge sheet receiver. Paper loading device to do. The receiving emissions paper sheet, sheet stacking apparatus according to claim 1 having a receiving lifting means moves up and down depending on the stack height of the discharge sheet. 3. The paper stacking apparatus according to claim 1, wherein the belt transport unit includes a plurality of travel belts arranged along a paper transport direction, and the plurality of travel belts are driven by a common belt drive unit. 4. The paper stacking apparatus according to claim 1, further comprising an air suction unit that sucks the paper onto the traveling belt by air as the paper suction unit. 5. 4. The paper stacking apparatus according to claim 1, further comprising an electrostatic adsorption unit that electrostatically adsorbs the sheet to the traveling belt as the sheet adsorption unit. 5. 6. An image forming apparatus according to claim 1 , wherein the sheet stacking apparatus according to claim 1 is attached to a sheet discharge port position for sending out the sheet on which an image has been recorded by an inkjet method .

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