JP4752601B2 - Suction-type belt conveying device, image forming apparatus - Google Patents

Description

  The present invention relates to a suction-type belt conveyance device that conveys an object to be conveyed placed on a belt while sucking it onto the belt, and an image forming apparatus having a recording paper conveyance means.

  2. Description of the Related Art Belt conveying apparatuses that convey an object to be conveyed placed on a belt by an endless belt that is stretched and driven between a plurality of rolls are widely used. In the belt conveyance device, in order to prevent the conveyed object from being detached from the belt in the middle of conveyance, it has been conventionally performed to convey the conveyed object by pressing the conveyed object with a pressing member such as a pressing roll.

  A plurality of small holes (hereinafter also referred to as suction holes) that allow ventilation between the front surface and the back surface of the belt are provided, and the object to be transported placed on the belt is transported while being sucked to the surface of the belt through the suction holes. A belt transport device (hereinafter also referred to as a suction belt transport device) does not require a pressing member such as a press roll to be transported since the transported material is not detached from the belt during transport. It is used as a transport device. The suction-type belt conveyance device is provided with a decompression chamber whose inside is maintained at an atmospheric pressure lower than atmospheric pressure by an exhaust means, and sucks a conveyed object placed on the belt through an adsorption hole of the belt toward the decompression chamber. Usually, the decompression chamber has a ventilation plate in which a plurality of ventilation holes that allow air to flow into the decompression chamber are arranged at a portion that abuts on the belt on the upper surface. The vent plate abuts the belt on a wide surface and also functions to support the belt. Then, the object to be conveyed is sucked to the surface of the belt by being sucked toward the decompression chamber through the suction hole of the belt and the vent hole of the vent plate of the decompression chamber.

  In such a suction-type belt conveyance device, the object to be conveyed is conveyed at the belt driving speed without being displaced from the belt placement position in the middle of conveyance. However, it is suitably used as a recording paper transport device of an image forming apparatus that outputs image information to the surface of the recording paper to form an image.

  By the way, the recording paper transport device used in the image forming apparatus requires that the recording paper is kept flat in the process of outputting the image information to the recording paper and that the recording paper transport speed does not change. Is done. In the suction-type belt conveyance device, since the object to be conveyed is sucked onto the belt, the recording paper sucked on the surface of the belt is spread along the surface of the belt so that the entire surface is in close contact with the surface of the belt. However, the surface of the recording paper may still float or sag. FIG. 8 is a diagram for explaining the background of the occurrence of floating or slack in the recording paper sucked on the surface of the belt in the conventional suction belt conveyance device. The belt, the ventilation plate, and the recording paper shown in FIG. 8 are cross-sectional views cut in a direction perpendicular to the belt driving direction (driven from the back side to the front side in the drawing) in the suction belt conveyance device. The lower direction of the vent plate in the drawing is a decompression space of the decompression chamber. The belt has a plurality of suction holes and the ventilation plate also has a plurality of ventilation holes. When the suction hole and the ventilation hole face each other, the recording paper is sucked to the decompression space side through the suction hole and the ventilation hole and is in close contact with the surface of the belt. FIG. 8A shows a state before the recording paper is sucked, and FIG. 8B shows a state where the recording paper is sucked. Note that the cross-sectional shape of the recording paper in FIG. 8 is exaggerated for explanation. FIG. 8A shows a state in which a recording sheet is placed on a belt having suction holes and is driven together with the belt, but the ventilation plate at a position facing the suction holes of the belt has no ventilation holes. The recording paper is not sucked to the decompression space side. FIG. 8B shows a state where the belt is driven and the suction hole reaches a position opposite to the vent hole, and the recording paper is sucked all at once in the direction of the arrow through the plurality of suction holes and the vent hole. The Here, the recording paper is sucked to the surface side of the belt, but the entire portion of the recording paper does not come into close contact with the surface of the belt, and the recording paper is floated or slackened. Occurrence of floating or slack in the transported recording paper is not preferable depending on the situation in which the recording paper transport device is used. In particular, an image that outputs image information on the surface of the recording paper and forms an image in a non-contact manner. When used in a forming apparatus, it adversely affects image formation, causing image quality degradation such as image blurring and density unevenness.

In the suction-type belt conveyance device, a method of pressing the object to be conveyed by a pressing member or air blow is disclosed for removing floating or slackness of the object to be conveyed (see Patent Document 1). However, the removal of the floating or slack of the object to be conveyed using the pressing member requires that the pressing member be brought into contact with the surface of the object to be conveyed, so that the use of the suction type belt conveying device is limited, and also by air blow The removal of the float and slack of the conveyed object cannot remove the float and slack generated in the process shown in FIG.
JP-A-7-61413

  Provided are a suction-type belt conveyance device that does not cause floating or slack in recording paper sucked on the surface of the belt, and an image forming apparatus incorporating the suction-type belt conveyance device.

The object is achieved by the following means.
1. An endless belt having a plurality of suction holes;
Drive means for driving the belt;
A plurality of pressure reductions arranged in a belt driving direction, which is a direction in which the belt is driven, in which a plurality of ventilation holes that allow ventilation inside and outside are arranged at a portion that abuts on the belt and abuts on the belt. Room,
A plurality of decompression means provided corresponding to each of the plurality of decompression chambers;
Have
Suction-type belt conveyance that conveys the belt by driving the belt in a predetermined direction by the driving means while sucking the conveyed object placed on the belt through the suction hole and the vent hole toward the decompression chamber side. A device ,
Through the vent holes, along the vent hole array including a plurality of which is Retsu置in a direction perpendicular to the belt drive direction, in each of the plurality of ventilation hole rows, which is disposed on the most upstream side in the driving direction of the belt The suction type belt conveying device, wherein the air holes arranged in line with the air holes are sequentially shifted in the downstream direction.
2. 2. The suction-type belt conveyance device according to 1, wherein the vent hole is a long hole having a dimension on the belt driving direction side larger than a dimension on a direction side orthogonal to the belt driving direction.
3. An image forming apparatus comprising the suction type belt conveying device according to item 1 or 2.

  According to the first aspect of the present invention, it is possible to provide a suction-type belt conveyance device that does not cause the recording paper sucked on the surface of the belt to float or loosen. According to the second aspect of the present invention, since the suction of the recording paper is not interrupted even when the belt moves, the recording paper is conveyed while maintaining close contact with the belt.

  Hereinafter, a suction-type belt conveyance device according to an embodiment of the present invention and an image forming apparatus incorporating the suction-type belt conveyance device according to an embodiment of the present invention will be described.

  FIG. 1 is a schematic diagram for explaining an example of an image forming apparatus incorporating a suction belt conveying apparatus according to an embodiment of the present invention.

  In FIG. 1, reference numeral 100 denotes an image forming apparatus, which is a recording paper supply unit 10, a recording paper transport unit 20, an image output unit 40, an image-formed recording paper storage unit 50, an operation input unit 60, A control unit 90 is provided. The image forming apparatus 100 outputs image or character information by the image output unit 40 to the recording paper P supplied from the recording paper supply unit 10 based on the information and data input from the operation input unit 60. Image formation is performed, and the image-formed recording paper P is accommodated in the image-formed recording paper accommodating unit 50. These image forming operations in the image forming apparatus 100 are controlled by the control unit 90. The recording paper transport unit 20 in the image forming apparatus 100 is provided with a suction belt transport device that is an embodiment of the present invention.

  The recording paper supply unit 10 includes a recording paper storage magazine 11 that is a container for storing the recording paper P that is a sheet body, a recording paper take-out roll 12, and a recording paper separation roll 13, and is stored in the recording paper storage magazine 11. The recorded recording paper P is taken out one by one and transported to the recording paper transporting unit 20.

  As described above, the suction type belt conveyance device which is an example of the embodiment of the present invention is arranged in the recording paper conveyance means unit 20. The suction-type belt conveyance device disposed in the recording paper conveyance unit 20 includes a drive roll 21 that is rotationally driven by a motor 23 that is a drive means, and a driven roll 22, and between the drive roll 21 and the driven roll 22. An endless belt 24 that is stretched and driven by the drive roll 21, and a decompression chamber comprising three small chambers 27a, 27b, and 27c forming a housing structure in a gap between the drive roll 21 and the driven roll 22 26. The small chambers 27a, 27b and 27c have decompression means 28a, 28b and 28c, respectively, and the inside of the housing structure in the small chambers 27a, 27b and 27c is a decompression space. Further, a vent plate 29 is provided at a portion of the top surface portion of the decompression chamber 26 that comes into contact with the belt 24. The vent plate 29 is a member constituting the top surface of the decompression chamber 26, and forms a housing structure in the small chambers 27a, 27b and 27c, and also functions to abut against the belt 24 and support the surface of the belt 24 on a flat surface. . The belt 24 is provided with a plurality of suction holes penetrating the front and back, and the vent plate 29 is provided with a plurality of vent holes penetrating the front and back.

  The object to be conveyed placed on the belt 24 is sucked to the decompression chamber 26 side through the vent hole and the suction hole, and is sucked and transported to the surface of the belt 24. The suction type belt conveyance device in the recording paper conveyance unit 20 will be described in detail later. In the suction-type belt conveyance device according to the embodiment of the present invention, the decompression chamber 26 is composed of three small chambers 27a and 27b, but the number of small chambers is not limited to three. It may be determined in accordance with the conditions under which the suction belt conveyance device is used.

  The image output unit 40 includes an ink ejecting head that is an image output unit. The image ejecting unit 40 ejects ink from the ink ejecting head onto the recording paper P conveyed below the image ejecting unit. Form. The image output unit 40 according to the present embodiment has four ink ejecting heads, 41Y, 41M, 41C, and 41K, and the recording paper P conveyed under the ink ejecting heads, 41Y, 41M. , 41C, and 41K, four color inks of Y (yellow), M (magenta), C (cyan), and K (black) are ejected to form a color image and characters on the recording paper P. The timing at which each of the ink ejection heads 41Y, 41M, 41C, and 41K ejects ink and the amount of ink to be ejected are controlled by the control means 90.

  The image-formed recording paper storage unit 50 has a paper discharge tray 51 and stores the recording paper P on which the image is formed by the image output unit 40.

  The operation input unit 60 includes information input means such as a plurality of push buttons, and can input information necessary for operating the image forming apparatus 100.

  Based on the information input from the operation input unit 60, the control unit 90 takes out the recording paper P one by one from the recording paper supply unit 10 and conveys it to the image output unit 40 by the recording paper conveyance unit 20. Then, the image output unit 40 outputs an image, and controls the operation of the image forming apparatus 100 so that the recording paper P on which the image has been formed is stored in the paper discharge tray 51 of the image-formed recording paper storage unit 50. To do. Further, the control unit 90 can output character information and image information transmitted from a signal line or personal computer connected via an interface unit (not shown) on the recording paper P as characters and images.

  FIG. 2 is a perspective view of a suction type belt conveyance device according to an embodiment of the present invention arranged in the recording paper conveyance means unit 20. In FIG. 2, the belt 24 is displayed with a part cut away so that a part of the ventilation plate 29 can be seen. As shown in FIG. 2, the belt 24 is stretched between the drive roll 21 and the driven roll 22. The belt 24 is formed with a plurality of suction holes 25 penetrating the front and back in the width direction and the longitudinal direction.

  The drive roll 21 is driven to rotate by a motor 23, and the belt 24 is driven in the direction indicated by the arrow AB. When the object to be conveyed is placed on the belt 24, the object to be conveyed is conveyed in the direction indicated by the arrow AB by driving the belt 24. In the description of the positional relationship in the following description, it may be expressed as the upstream side or the downstream side in the belt driving direction. The belt driving direction means the direction from the B side to the A side in the illustrated arrow AB. In this case, the upstream side in the belt driving direction represents the B side of the illustrated arrow AB, and the downstream side in the belt driving direction represents the A side of the illustrated arrow AB.

  28a, 28b, and 28c are decompression means, respectively, and the air inside the small chambers 27a, 27b, and 27c is exhausted by an exhaust pump or the like, and the inside of the small chambers 27a, 27b, and 27c is decompressed at a pressure lower than atmospheric pressure Keep on.

  The ventilation plate 29 functions as a member constituting the top surface of the small chambers 27a, 27b and 27c, forming a casing in the small chambers 27a, 27b and 27c, and supporting the belt 24 by contacting the inner peripheral surface of the belt. .

A vent hole row 31a is formed at the top surface of the small chamber 27a of the vent plate 29. The vent hole row 31a is formed by arranging a plurality of vent holes penetrating the front and back in a direction orthogonal to the driving direction of the belt.
Similarly, in the portion that becomes the top surface of the small chamber 27b, a vent hole row 31b in which a plurality of vent holes penetrating the front and back in a direction orthogonal to the driving direction of the belt is arranged in the portion that becomes the top surface of the small chamber 27c. Is formed with a vent hole row 31c in which a plurality of vent holes penetrating the front and back are arranged in a direction perpendicular to the belt driving direction.

  In FIG. 2, a vent hole row 31 a at the top surface portion of the small chamber 27 a is shown in the cut portion of the belt 24. Through these vent hole rows 31a, 31b and 31c, suction is performed toward the decompressed small chambers 27a, 27b and 27c.

  FIG. 3 is a diagram illustrating the vent hole rows 31a, 31b, and 31c. FIG. 3A is a view of the ventilation plate 29 as viewed from the side that contacts the belt 24. FIG. 3B shows the ventilation holes located at the centers of the ventilation hole rows 31a, 31b, and 31c. It is sectional drawing cut | disconnected by the position.

In FIG. 3A, reference numerals 30a _{1 to} 30a ₂₇ denote vent holes forming the vent hole row 31a. In the embodiment, the vent hole row 31a is formed from the ₂₇ vent holes of the vent holes 30a _{1 to} 30a _27. Is formed. The ventilation holes 30a ₁ and 30a ₂₇ are ventilation holes located at both ends of the ventilation hole row 31a, and the ventilation holes 30a ₁₄ are intake holes located at the center of the ventilation hole row 31a.

Further, 30b _{1 to} 30b ₂₇ are ventilation holes forming the ventilation hole row 31b. In the embodiment, the ventilation hole row 31b is formed of 27 ventilation holes, the ventilation holes 30b _{1 to} 30b ₂₇ . The vent hole 30b ₁ and the vent hole 30b ₂₇ are vent holes located at both ends of the vent hole row 31a, and the vent hole 30b ₁₄ is an intake hole located at the center portion of the vent hole row 31b.

Similarly, 30c ₁ to 30c ₂₇ are vent holes forming the vent hole row 31c, and in the embodiment, the vent hole row 31c is formed of 27 vent holes of the vent holes 30c _{1 to} 30c ₂₇ . . The vent hole 30c ₁ and the vent hole 30c ₂₇ are vent holes located at both ends of the vent hole row 31c, and the vent hole 30c ₁₄ is an intake hole located at the center portion of the vent hole row 31a.

  The number of air holes forming each air hole array is not limited to 27, but the suction type such as the size of the recording paper P to be conveyed and the direction in which the recording paper P is placed on the belt. You may determine suitably according to the conditions in which a belt conveying apparatus is used.

The central vent holes 30a ₁₄ , 30b ₁₄ , and 30c ₁₄ in the vent hole rows 31a, 31b, and 31c have the upstream end in the belt driving direction at the most upstream in the respective vent hole rows 31a, 31b, and 31c. Formed in position. In addition, the air holes arranged on both sides of the air holes 30a ₁₄ , 30b ₁₄ , and 30c ₁₄ have upstream ends in the belt driving direction with respect to the air holes 30a ₁₄ , 30b ₁₄ , and 30c _14. Are formed so as to be sequentially positioned downstream in the respective belt driving directions. On the other hand, the downstream ends of the air holes in the air hole rows 31a, 31b, and 31c in the belt driving direction are arranged on a straight line orthogonal to the belt driving direction.

  Subsequently, the vent hole rows 31a, 31b and 31c will be described by taking the vent hole row 31a as an example.

FIG. 4 is a diagram for explaining the details of the air holes in the air hole row 31a. As shown in FIG. 4, the vent holes 30 a _{1 to} 30 a ₂₇ forming the vent hole row 31 a have an elongated hole shape, and the adjacent vent holes in the width direction are parallel to the belt drive direction. With a space P between them. The width dimension of each vent hole is W. The specific dimensions of P and W may be determined in accordance with the conditions under which the suction belt conveyance device is used.

The vent hole 30a ₁₄ located at the central portion of the vent hole row 31a is formed such that the end face in the longitudinal direction is located at the most upstream position of the vent hole row 31a. Further, with respect to the vent hole 30a _14, vents 30a ₁₃ upward in the drawing side, 30a _12, 30a _11, reaches the vent holes 30a ₁ of ... is arrayed end, the vent hole 30a in the illustrated lower side ₁₅ , 30 a ₁₆ , 30 a ₁₇ ,... Are arranged in a row and reach the vent hole 30 a ₂₇ at the end.

As described above, the air hole 30a ₁₄ has the upstream end in the belt driving direction formed at the most upstream position in the air hole row 31a, and is in line with the air hole 30a ₁₄ to form the air hole row 31a. vent end of each belt drive direction upstream side is formed by sequentially shifted in the downstream direction with respect to the end portion of the belt drive direction upstream side of the vent hole 30a _14.

  In other words, each vent hole forms a vent hole row arranged in a direction orthogonal to the belt driving direction, which is the direction in which the belt is driven, and is arranged on the most upstream side in the belt driving direction in the vent hole row. The vent holes in line with the provided vent holes are sequentially shifted in the downstream direction.

FIG. 5 is a diagram illustrating the suction holes. 5A is a view of the belt 24 as seen from the contact surface side with respect to the belt 24, and FIG. 5B is a cross-sectional view as seen from the front side. In FIG. 5, the belt 24 is shown with a part cut away so that the vent hole row 31b can be seen.
As shown in FIG. 5, the belt 24 is stretched between the drive roll 21 and the driven roll 22 and is driven in the arrow AB direction by the drive roll 21 that is rotationally driven.

  As shown in FIG. 5A, the belt 24 has a plurality of suction holes 25 penetrating the front and back. Each suction hole 25 is circular, and its diameter is d. The specific dimension of d may be determined in accordance with the conditions under which the suction belt conveyance device is used. Then, they are arranged on the straight line in the direction orthogonal to the belt driving direction with the same interval P as the interval between the vent hole rows. When the belt 24 is driven to reach a position where any one of the suction holes 25 of the belt 24 is opposed to any one of the vent holes 31a, 31b, and 31c in the vent plate 29, the air holes and the suction holes are sucked. Through the hole 25, suction is performed toward the small chambers 27a, 27b, and 27c, and the object to be conveyed placed on the belt 24 is sucked to the surface of the belt 24. On the other hand, the object to be conveyed is not sucked from the suction hole 25 of the belt 24 that does not match any of the vent holes 28.

  In the suction-type belt conveyance device configured as described above, the object to be conveyed is conveyed while being sucked to the surface of the belt, so that the object to be conveyed is attracted to the belt and does not deviate from the belt placement position. In the suction-type belt conveyance device to which the present invention is applied, when the conveyance object is a sheet body such as paper, the conveyance object placed on the belt is further lifted or slackened. It can be transported without being generated.

  FIG. 6 is a diagram for explaining the operation of the suction-type belt conveyance device to which the present invention is applied to convey the object to be conveyed without causing floating or slack. In FIG. 6, the recording paper P, which is the object to be conveyed, is placed on the belt 24, and the process of conveyance is sequentially illustrated in FIGS. 6A, 6 </ b> B, 6 </ b> C, and 6. This is shown in (d). The cross-sectional shape of the recording paper P placed on the surface of the belt 24 is shown in each XX cross-section. Note that floating and slackening are exaggerated in the cross-sectional shape of the recording paper P in the XX cross section shown in the figure.

  FIG. 6A shows a state where the recording paper P, which is a transported object, is placed on the belt 24.

  The belt 24 has a plurality of suction holes 25 arranged on a straight line in a direction orthogonal to the belt driving direction, and the holes 24 a and 31 b in which the suction holes 25 of the belt 24 are provided on the ventilation plate 29. , 31c, the object to be transported placed on the suction hole 25 is sucked when facing one of the vent holes. In the position shown in FIG. 6A, the suction of the recording paper P is not performed since none of the suction holes 25 arranged at the position where the belt 24 places the recording paper P reaches the position of the vent hole row 31a. . As shown in the XX cross section, the recording paper P is placed on the surface of the belt 24 with floating or slack.

FIG. 6B shows a state where the belt is driven and the suction hole on the left end side of the belt 24 where the recording paper P is placed reaches the position where the vent hole row 31a is formed. Show.
In the vent hole row 31a, the end of the vent hole 30a ₁₄ on the upstream side in the belt driving direction is formed at the most upstream position in the belt driving direction, and therefore, through the suction hole facing the vent hole 30a ₁₄ in the suction hole row. The recording paper P is sucked. A position at which the recording paper P is sucked is indicated by S. At this time, the recording paper P is sucked onto the surface of the belt 24 at the S position as shown in the XX cross section. In the position, there is a float or a slack.

FIG. 6C shows a state in which the belt is further driven and a plurality of suction holes opposed to the air holes of the air hole array 31a are formed. Since the vent hole 30a ₁₄ has a long hole shape, even if the belt is further driven from the state of FIG. 6B, the suction hole from which the recording paper P is sucked in FIG. 6B is the vent hole 30a. _Since it faces ₁₄ , suction is not interrupted. Since there are a plurality of suction holes facing the vent hole row 31a, there are a plurality of positions S where the recording paper P is sucked.

At this time, the recording paper P is sucked onto the surface of the belt 24 at a plurality of S positions and is brought into close contact with the belt 24 as shown in the XX cross section. The contact position of the recording paper P to the belt 24 starts from one position facing the vent hole 30a ₁₄ , and gradually expands to the outside in the width direction of the recording paper P as the belt is driven. The range without slack gradually increases toward the outside in the width direction of the recording paper P.

FIG. 6D shows a state in which the belt is further driven and all the suction hole rows on the left end side at the position where the recording paper P is placed on the belt 24 have reached a position facing the air hole row 31a. In this state, since suction is performed from all the suction holes in the suction hole row on the left end side of the belt 24 where the recording paper P is placed, the recording paper P is in close contact with the belt on the left end side of the drawing. Then, subsequent to FIG. 6 (c), the contact position of the belt 24 of the recording sheet P starts from only one point that faces the vent holes 30a _14, to expand outwardly in the width direction of the sequential recording paper P recording paper By reaching the entire region in the width direction of P, the entire region in the width direction of the recording paper P comes into close contact with the belt 24, and as shown in the XX cross section, the suction hole array on the left end side of the recording paper P in the width direction in the drawing is shown. Floats and slacks are eliminated over the entire area.

Further, as shown in FIGS. 6C and 6D, as the belt 24 is driven, the upstream side position of the suction hole array on the left end side at the position where the recording paper P is placed on the belt 24, Since the portion S where the recording paper P is sucked is formed at one location facing the vent hole 30a ₁₄ , the recording paper P is gradually expanded outward in the width direction of the recording paper P. And the floating and slack are eliminated over the entire surface of the recording paper P. Also, since each vent hole has a long hole shape, the portion where the suction holes of the belt face each other and suction starts is a long hole even if the suction hole moves by driving the belt 24. Since they face each other, the suction of the recording paper P is not interrupted, and the recording paper P is always conveyed while maintaining close contact with the belt 24.

  The operation for eliminating the floating or slack of the recording paper P has been described as an example when the recording paper P reaches the position of the vent hole row 31a. However, the recording paper P is further vented toward the downstream side in the transport direction. Even when the positions of the 31b and the vent hole row 31c are reached, the suction and the slack of the recording paper P are eliminated by the suction from the vent hole row 31b and the vent hole row 31c. Can be transported in the absence of

Up to now, in the vent hole row 31a, the configuration in which the upstream end in the belt driving direction is the vent hole 30a ₁₄ located in the center as the vent hole formed in the most upstream position in the vent hole row will be described. However, the vent hole formed at the most upstream position in the vent hole row is not limited to the vent hole located in the central portion of the vent hole row, and any vent hole in the vent hole row can be connected to the end thereof. May be a vent located at the uppermost stream in the row of vent holes.

FIG. 7 is a diagram showing an example of a configuration in which the vent hole whose end is positioned at the uppermost stream in the vent hole row is not the vent hole located in the central portion of the vent hole row in the vent hole row 31a. FIG. 7A shows a configuration in which the vent hole 30a ₂₇ located at one end of the vent hole row 30a is a vent hole whose end is located at the uppermost stream in the vent hole row, and FIG. 7B shows the vent hole row 30a. FIG. 5 is a diagram showing a configuration in which the vent hole 30a ₂₁ located in the middle between the end portion and the center portion is a vent hole whose end portion is located in the uppermost stream in the vent hole row.

7A and 7B, the portion S where the recording paper P is sucked as the belt 24 is driven is formed at one position facing the vent hole 30a ₂₇ or the vent hole 30a _21. Since the recording paper P is sequentially enlarged in the width direction of the recording paper P, the recording paper P is in close contact with the belt on the entire surface, and floating and slacking are eliminated over the entire surface of the recording paper P.

  As described above, the vent hole formed at the most upstream position in the vent hole row is not limited to the vent hole located in the central portion of the vent hole row. The present invention is also applied to the pore row 31b and the vent hole row 31c.

  As described above, the suction-type belt conveyance device according to the present invention does not cause positional deviation between the conveyance object and the belt, and can convey the conveyance object at the belt driving speed. Even if a member to be pressed is not used, the conveyed object is not lifted or slacked. Therefore, the present invention can be suitably applied to a recording paper conveying unit such as an image forming apparatus that forms an image while moving the image forming unit in a non-contact manner at a constant speed.

It is a schematic diagram explaining an example of the image forming apparatus incorporating the suction type belt conveying apparatus which is embodiment of this invention. It is a perspective view of the suction type belt conveyance device which is an embodiment of the invention. It is a figure explaining the vent hole row distribute | arranged to the ventilation board. It is a figure explaining the detail of the vent hole in a vent hole row | line | column. It is a figure explaining a suction hole. It is a figure explaining the effect | action which the attraction | suction type belt conveyance apparatus to which this invention is applied conveys to a to-be-conveyed object, without generating a float and slack. It is a figure which shows the example of a structure which does not make the vent hole located in the uppermost stream in a vent hole row | line | column in a vent hole row | line | column into the vent hole located in the center part in a vent hole row | line | column. In the conventional suction type belt conveying device, it is a diagram for explaining how the recording paper sucked on the surface of the belt is lifted or slackened.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Recording paper supply means part 11 Recording paper storage magazine 12 Recording paper taking-out roll 13 and recording paper separation roll 20 Recording paper conveyance means part 21 Drive roll 22 Driven roll 23 Motor 24 Belt 25 Adsorption hole 26 Decompression chamber 27 Small chamber 28 Decompression means 29 Ventilation plate 30 Ventilation hole 31 Ventilation hole array 40 Image output means 40
41 Ejection head 50 Image-formed recording paper storage means section 50
51 Paper Discharge Tray 60 Operation Input Unit 90 Control Unit 100 Image Forming Apparatus P Recording Paper

Claims (3)

An endless belt having a plurality of suction holes;
Drive means for driving the belt;
A plurality of pressure reductions arranged in a belt driving direction, which is a direction in which the belt is driven, in which a plurality of ventilation holes that allow ventilation inside and outside are arranged at a portion that abuts on the belt and abuts on the belt. Room,
A plurality of decompression means provided corresponding to each of the plurality of decompression chambers;
Have
Suction-type belt conveyance that conveys the belt by driving the belt in a predetermined direction by the driving means while sucking the conveyed object placed on the belt through the suction hole and the vent hole toward the decompression chamber side. A device ,
Through the vent holes, along the vent hole array including a plurality of which is Retsu置in a direction perpendicular to the belt drive direction, in each of the plurality of ventilation hole rows, which is disposed on the most upstream side in the driving direction of the belt The suction type belt conveying device, wherein the air holes arranged in line with the air holes are sequentially shifted in the downstream direction. 2. The suction-type belt conveyance device according to claim 1, wherein the vent hole is a long hole having a dimension on the belt driving direction side larger than a dimension on a direction side orthogonal to the belt driving direction. An image forming apparatus comprising the suction type belt conveying device according to claim 1.

Images