JP2012188203A - Ejection device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit a trailing edge of a recording medium from rubbing against a guide member for guiding the recording medium in a direction where the recording medium approaches an ejection position.SOLUTION: The guide member 55 comes in contact with the recording medium conveyed by a conveying part 50 and guides the recording medium in the direction where the recording medium approaches the ejection position at which the recording medium is ejected. Ejection rolls 71U and 71L hold the recording medium between the contact areas N of roll members 712U and 712L, and eject the recording medium to a medium receiving part 80. Roll members 722R and 722L are provided at positions at which they are opposed to each other in a width direction of the recording medium on a downstream side in the conveying direction of the ejection rolls 71U and 71L (shown by an arrow C3 in the figure) when they are seen from the positions of the ejection rolls 71U and 71L. The roll members 722R and 722L each have a part crossing a tangential plane including a tangent in each of the contact areas N of the plurality of roll members 712U and 712L.

Description

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

  In the image forming apparatus, in order to improve the storage capacity of the recording medium in the medium receiving section, a streak having a component in the transport direction is generated in the recording medium, and the medium receiving section outside the apparatus is in a state where the rigidity of the recording medium is increased. (For example, Patent Documents 1 and 2).

Japanese Patent Laid-Open No. 03-67852 JP 2002-87675 A

  An object of the present invention is to suppress the trailing end of a recording medium from rubbing against a guide member that guides the recording medium in a direction approaching a discharge position.

  According to a first aspect of the present invention, there is provided a discharging device that contacts the recording medium that is transported by the transporting means and a recording medium that is transported by the transporting means and approaches the discharge position where the recording medium is ejected. A plurality of pairs of rolls each having a guide member for guiding a medium and two rolls whose outer circumferences are in contact with each other and rotating around a rotation axis, wherein the recording medium guided by the guide member is the 2 A plurality of roll pairs sandwiched between the contact areas of the two rolls and discharging the recording medium to the discharge position; and at least one of the contacts on the downstream side of the plurality of roll pairs in the conveyance direction of the recording medium Two contact members which are provided on the sides closer to both ends of the rotation shaft than the region and come into contact with the recording medium discharged by the roll pair, as viewed from the direction along the rotation shaft. In, characterized in that it comprises a contact member having a portion intersecting the tangent plane including the tangential line at each of the contact area of the plurality of roll pairs.

  According to a second aspect of the present invention, there is provided a discharge device according to the first aspect, wherein the contact member rotates in contact with a recording medium discharged by the roll pair.

  The discharge device according to a third aspect of the present invention is characterized in that, in the configuration according to the second aspect, the contact member has a portion that decreases as the roll diameter approaches the plurality of roll pairs.

  According to a fourth aspect of the present invention, there is provided a discharge device according to any one of the first to third aspects, wherein an image corresponding to image data is transferred to a recording medium and then fixed by heating and pressing. The image forming means for forming an image on the recording medium and the recording medium on which the image is formed by the image forming means are transported and discharged to a discharge position.

  According to a fifth aspect of the present invention, in the configuration according to the fourth aspect, a determination unit that determines an attribute of a recording medium on which an image is formed by the image forming unit, and a determination result by the determination unit. And a moving means for moving the contact member of the discharging device to a corresponding position.

  An image forming apparatus according to a sixth aspect of the present invention is characterized in that, in the configuration according to the fifth aspect, the attribute of the recording medium is a size of the recording medium.

  An image forming apparatus according to a seventh aspect of the present invention is characterized in that, in the configuration according to the fifth aspect, the attribute of the recording medium is a material of the recording medium.

According to the configuration of the first and fourth aspects, the contact member that generates the streak having the component in the transport direction on the recording medium is more upstream in the transport direction than the roll that discharges the recording medium to the discharge position. Or compared with the case where it is provided in the same position in the said conveyance direction, it can suppress that the rear end of the recording medium rubs against a guide member.
According to the structure of Claim 2, compared with the case where a contact member does not rotate, the resistance by the contact with respect to a recording medium from the contact member can be made small.
According to the structure of Claim 3, compared with the case where a contact member has an angle | corner, possibility that a crease | fold and a wrinkle will arise on the surface of a recording medium can be made small.
According to the structure of Claim 5, it can suppress that the rear end of the recording medium scrapes a guide member irrespective of the attribute of a recording medium.
According to the configuration of the sixth aspect, it is possible to suppress the trailing end of the recording medium from rubbing against the guide member regardless of the size of the recording medium.
According to the structure of Claim 7, it can suppress that the rear end of the recording medium scrapes a guide member irrespective of the material of a recording medium.

1 is a diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a schematic diagram illustrating a configuration around a fixing unit and a discharge device according to the embodiment. It is a figure which shows the structure of the conventional discharge device. It is the perspective view which showed the external appearance of the discharge device which concerns on the same embodiment. It is a figure explaining the contact area of the discharge roll which concerns on the same embodiment, and the position of a contact roll. It is the figure which showed an example of the positioning table which concerns on the same embodiment. FIG. 6 is a diagram of the discharge device according to the embodiment viewed from the positive direction of the Z axis, and is a diagram illustrating a relationship between the size of the recording medium and the position of the roll member. It is a figure explaining the contact area of the discharge roll which concerns on the same embodiment, and the position of a contact roll. It is a graph which shows the comparison result with a prior art example about the contact force between the guide member which concerns on the embodiment, and a recording medium. It is a figure explaining the contact area of the discharge roll which concerns on the modification of this invention, and the position of a contact roll. It is the figure which showed an example of the positioning table which concerns on the modification of this invention.

[Embodiment]
FIG. 1 is a diagram illustrating a configuration of an image forming apparatus according to an embodiment of the present invention. The image forming apparatus 1 is an apparatus that forms an image according to input image data on a recording medium, and includes a control unit 10, a communication unit 20, a display operation unit 30, a supply unit 40, and a conveyance unit 50. The image forming unit 60, the discharge device 70, and the medium receiving unit 80 are provided. In the following drawings, directions are indicated by the X axis, the Y axis, and the Z axis that are orthogonal to each other. When the image forming apparatus 1 is viewed from the front, the horizontal direction is the X axis direction, and the depth direction is the Y axis. The direction of height and the height direction are the Z-axis direction. Also, in the figure, “•” in “◯” means an arrow heading from the back of the drawing to the front. Further, in the figure, “x” in “◯” means an arrow pointing backward from the front of the drawing.

  The control unit 10 includes an arithmetic device such as a CPU (Central Processing Unit) and an ASIC (Application Specific Integrated Circuit), and a memory such as a ROM (Read Only Memory) and a RAM (Random Access Memory). The CPU controls the operation of each unit of the image forming apparatus 1 by executing a program stored in the memory. The communication unit 20 is connected to a terminal device (not shown) via a network or the like, and performs communication with this terminal device. The display operation unit 30 is, for example, a touch panel, displays an image for guiding the operation according to the control of the control unit 10, and supplies an operation signal corresponding to the user's operation to the control unit 10.

  The supply unit 40 accommodates a recording medium and supplies the recording medium. Here, the recording medium is a sheet-like medium on which an image is formed by the image forming apparatus 1, and is, for example, paper. The size and the material of the recording medium are not particularly limited as long as they correspond to the image forming apparatus 1. The conveyance unit 50 includes a conveyance belt, a conveyance roll, and the like, conveys the recording medium supplied from the supply unit 40 to the image forming unit 60, and then the recording medium on which an image is formed by the image forming unit 60. Is conveyed to the discharge device 70. That is, the transport unit 50 is an example of a transport unit. For convenience of explanation, in the following, a direction orthogonal to the conveyance direction of the recording medium (a direction perpendicular to the paper surface of FIG. 1) is referred to as a “width direction of the recording medium”.

  The image forming unit 60 includes photoreceptor units 61Y, 61M, 61C, and 61K, an exposure unit 62, a belt unit 63, and a fixing unit 64. The photoreceptor units 61Y, 61M, 61C, and 61K correspond to yellow (Y), magenta (M), cyan (C), and black (K) colors, respectively, and images (hereinafter referred to as toner images) of the respective colors. Used to form and hold a toner image). The photoconductor units 61Y, 61M, 61C, and 61K each include a rotating roll-shaped photoconductor drum, a charger, a developer, and the like. The photosensitive drums of the respective colors are in contact with the intermediate transfer belt 631 at different positions. In the following, when it is not necessary to distinguish each of the photoconductor units 61Y, 61M, 61C, and 61K, these are collectively referred to as “photoconductor unit 61”. The exposure unit 62 irradiates each of the photoconductor units 61 with light and generates a potential difference in the photoconductive layer to form an electrostatic latent image. The electrostatic latent image on the photosensitive drum is developed by a developing device.

  The belt unit 63 includes an intermediate transfer belt 631, a plurality of primary transfer rolls 632Y, 632M, 632C, and 632K, a plurality of support rolls 633, 634, 635, 636, and 637, and a secondary transfer roll 638. The intermediate transfer belt 631 is an endless belt member to which each color toner image formed by the photosensitive unit 61 is transferred. The intermediate transfer belt 631 rotates in the direction indicated by the arrow A1 in the drawing while being supported by the support rolls 633 to 637. The primary transfer rolls 632Y, 632M, 632C, and 632K correspond to the photoreceptor units 61Y, 61M, 61C, and 61K, and transfer the toner images formed on the opposing photoreceptor drums to the intermediate transfer belt 631. The support rolls 633 to 637 are roll-shaped members that support the intermediate transfer belt 631 in a rotatable state. At least one of the support rolls 633 to 637 is rotated by a driving force given by a driving unit (not shown) to rotate the intermediate transfer belt 631. The secondary transfer roll 638 is opposed to the intermediate transfer belt 631 to form an area where the toner and the recording medium are sandwiched, and the toner image transferred to the intermediate transfer belt 631 is transferred to the recording medium in this area. In the following description, an area where toner or a recording medium is sandwiched is referred to as a contact area. The fixing unit 64 heats and pressurizes the recording medium with a pair of opposing rolls, and fixes the toner image transferred to the recording medium. In other words, the image forming unit 60 is an example of an image forming unit, and forms an image on the recording medium by transferring the image corresponding to the image data to the recording medium and fixing it by heating and pressing. The toner image is an example of an image corresponding to image data. The recording medium is transported to the discharge device 70 by the transport unit 50.

  Next, the configuration around the fixing unit 64 and the discharge device 70 will be described with reference to FIG. FIG. 2 is a schematic diagram showing a configuration around the fixing unit 64 and the discharge device 70. As shown in the drawing, the recording medium B2 that has undergone the fixing process by the fixing unit 64 is transported along the transport direction A21 in the positive Z-axis direction. This transport direction changes by a certain angle (90 degrees here) in the positive direction of the X axis, and thereafter the recording medium B2 is transported along the transport direction A22 (the positive direction of the X axis). . A guide member 55 for guiding the recording medium B2 transported from the fixing unit 64 to the discharge device 70 is provided in the transport path 50 between the fixing unit 64 and the discharge device 70. The contact surface of the guide member 55 with the recording medium B2 is curved with respect to the transport direction A21 and the transport direction A22, and the recording medium B2 is guided along the curved surface. Then, the recording medium is discharged to the medium receiving unit 80 by the discharge device 70 and is accommodated by being stacked on the medium receiving unit 80. That is, the guide member 55 contacts the recording medium conveyed by the conveying unit 50 and guides the recording medium in a direction approaching the discharge position where the recording medium is discharged. The medium receiving unit 80 is an example of a discharge position from which the recording medium is discharged. The reason for guiding the recording medium B2 along the curved surface is that it is necessary to arrange each part in the apparatus without gaps as much as possible for the purpose of downsizing the entire image forming apparatus, and to reduce each part. This is because of this.

  By the way, in general, an image forming apparatus fixes a toner image transferred from a photosensitive member to a recording medium by heating and pressurizing at a fixing unit, and records between two roller pairs provided opposite to each other. The medium is guided and conveyed in a direction corresponding to the rotation direction of the roller pair while sandwiching the recording medium with a frictional force generated between them. At this time, the recording medium may be curled due to dehumidification or pressing. Further, when the recording medium is discharged from the discharge device, the leading edge of the recording medium may hang down due to its own weight. Here, curling means that the recording medium is curved with respect to the transport direction. The recording medium ejected in a curled state is also in a curled state in the medium receiving part, so that it does not overlap one another or the ends thereof become uneven. Causes sex to deteriorate. Therefore, a conventional discharging apparatus uses a method in which a streak having a component in the transport direction is generated on the recording medium, and the recording medium is discharged to the medium receiving portion with increased rigidity. The rigidity here refers to the degree of change in posture with respect to external force. In particular, in the present embodiment, the state where the recording medium has high rigidity means that the recording medium maintains the posture along the transport direction as much as possible. It means a state where the tip hangs down due to its own weight when discharged. The magnitude of this rigidity depends on the second moment of section in the section in the thickness direction of the recording medium.

  Here, a method by which the conventional discharge device discharges the recording medium B3 to the medium receiving portion will be described. FIG. 3 is a diagram illustrating a configuration of a conventional discharge device 90. The discharge device 90 includes a discharge roll 91 and a corrugation roll 92 that are provided to face each other across the transport unit. The discharge roll 91 conveys the recording medium B3 by rotating about the rotation shaft 911. The discharge roll 91 includes a rotation shaft 911 and a plurality of roll members 912 provided at predetermined intervals in the axial direction of the rotation shaft 911. The corrugation roll 92 is a member for generating a stripe M having a component in the transport direction on the recording medium B3, and a plurality of rolls provided at predetermined intervals in the axial direction of the rotary shaft 921 and the rotary shaft 921. Member 922. The discharge roll 91 and the corrugation roll 92 are provided along the width direction of the recording medium B3, and the roll member 912 and the roll member 922 are provided so as not to contact each other. The discharge device 90 configured in this manner sandwiches the conveyed recording medium B3 between the roll member 912 and the roll member 922, thereby causing a plurality of streaks M having components in the conveying direction to be recorded on the recording medium B3. generate. Then, the discharge device 90 discharges the recording medium B3 to the medium receiving portion in this state. When the recording medium B3 is ejected in a state where the rigidity of the recording medium B3 is increased, curling generated in the fixing process on the recording medium B3 can be corrected, and the amount by which the tip of the recording medium B3 hangs down by its own weight can be reduced. Therefore, each recording medium B3 can be accommodated while being stacked in the medium receiving portion in a straight posture along the transport direction.

  By the way, the discharge device 90 has a streak M having a component in the transport direction not only on the portion of the recording medium B3 located on the downstream side of the corrugation roll 92 but also on the portion of the recording medium B3 located on the upstream side. generate. That is, the rigidity of the portion of the recording medium B3 located on the upstream side of the corrugation roll 92 is increased, and the posture is straight and nearly parallel to the transport direction. At this time, when the guide member 55 having the curved shape as described above is provided on the upstream side of the discharge device 90, a portion close to the rear end of the recording medium B3 in a posture close to the direction along the transport direction. Is rubbed by the guide member 55. The sliding sound generated by this rubbing may become noise.

  Returning to the description of the discharge device 70 of the present embodiment. FIG. 4 is a perspective view showing the appearance of the discharge device 70. The discharge device 70 includes discharge rolls 71U and 71L, contact rolls 72R and 72L, and a drive mechanism 73. In addition, since the structure of discharge roll 71U and 71L is the same, when it is not necessary to distinguish both about each member, description of "U" and "L" is abbreviate | omitted. Similarly, since the configurations of the contact rolls 72R and 72L are the same, the description of “R” and “L” is omitted when there is no need to distinguish between the two for each member. Similarly, the description of “U”, “L”, and “R” is omitted for each member constituting the discharge rolls 71U and 71L and the contact rolls 72R and 72L.

  The discharge roll 71 includes a rotation shaft 711 and a plurality of (four in this embodiment) roll members 712. The roll member 712 is a columnar member, and is provided at a predetermined interval in the axial direction of the rotation shaft 711. The discharge rolls 71U and 71L are provided in the width direction of the recording medium, and are provided such that the outer circumferences of the roll member 712U and the roll member 712L are in contact with each other to form a contact region. The discharge roll 71L is given a driving force by a motor (not shown) and rotates about the rotation shaft 711L in the direction of the arrow C1. On the other hand, the discharge roll 71U rotates in the direction of the arrow C2 around the rotation shaft 711U following the rotation of the discharge roll 71L. The discharge roll 71L and the discharge roll 71U sandwich the recording medium between the contact areas of the roll member 712U and the roll member 712L, transport the recording medium in the direction of arrow C3, and discharge it to the medium receiver 80. That is, the discharge roll 71U and the discharge roll 71L have a plurality of roll members 712U and 712L whose outer circumferences are in contact with each other, and are a plurality of roll pairs that rotate around the rotation axis. 4 is an example of a plurality of roll pairs that are sandwiched between contact areas and discharge a recording medium to the medium receiving unit 80. FIG.

  The contact roll 72 includes a rotating shaft 721, a roll member 722, and a support member 723. The support members 723R and 723L are provided on the downstream side with respect to the transport direction of the discharge roll 71 (arrow C3 in the drawing) when viewed from the position of the discharge roll 71, and at positions facing the recording medium in the width direction. The roll member 722 has a shape having a portion that becomes smaller as the roll diameter approaches the roll member 712, for example, an elliptical shape when viewed from the X-axis positive direction and the Z-axis positive direction, and is provided at one end of the rotation shaft 721. ing. The other end of the rotation shaft 721 is provided to be rotatable with respect to the support member 723. The contact roll 72 receives a driving force from a motor (not shown) and rotates around the rotation shaft 721 in the direction of the arrow C4.

  FIG. 5 is a diagram for explaining the contact area N of the discharge roll 71 and the position of the contact roll 72. FIG. 5 is a view of the discharging device 70 of FIG. 4 as viewed from the positive direction of the X axis. As will be described later, the roll member 722R and the roll member 722L can move in the width direction of the recording medium. However, as shown in FIG. In view of this, there is one or more contact areas N. That is, the roll member 722 </ b> R and the roll member 722 </ b> L are provided on the sides closer to both ends of the rotation shaft 711 of the discharge roll 71 than at least one contact region. For example, in FIG. 5A, there are four contact regions N between the position of the end portion P41 of the roll member 722L in the Y axis positive direction and the position of the end portion P42 of the roll member 722R in the Y axis negative direction. There is. The tangent plane D1 is a plane including a tangent line in each of the contact regions N of the roll member 712U and the roll member 712L when viewed from the axial direction (Y-axis direction) of the discharge roll 71. FIG. 2 shows a tangent plane D1 viewed from the positive direction of the Y axis. Further, as shown in FIG. 5B, the roll member 722R is provided so that a part of the roll member 722R protrudes in the positive direction of the Z axis from the tangential plane D1, and has a portion that intersects the tangential plane. . Similarly to the roll member 722R, the roll member 722L is provided so that a part of the roll member 722L protrudes in the positive direction of the Z axis from the tangential plane D1, and has a portion that intersects the tangential plane. Specifically, the position of the end portion P43 of the roll member 722 in the Z-axis positive direction is closer to the Z-axis positive direction side than the tangential plane D1 including the contact region N. Further, the position of the midpoint P45 of the straight line connecting the end P43 in the positive Z-axis direction and the end P44 in the negative Z-axis direction of the roll member 722 is more negative than the tangential plane D1 including the contact region N. On the direction side. That is, the roll member 722 </ b> R and the roll member 722 </ b> L are examples of contact members, and come into contact with the recording medium discharged by the discharge roll 71. In FIG. 5B, a gap is provided between the roll member 712U and the roll member 712L. However, in reality, no gap is provided, and the roll member 712U and the roll member 712L are in contact with each other. Thus, the contact region N is formed.

  Here, a case will be described in which the recording medium is sandwiched between the roll member 712U and the roll member 712L in the contact region N, and both end portions in the width direction of the recording medium are in contact with the roll members 722L and 722R. In this case, the recording medium has a curved shape along the guide member 55 on the upstream side in the conveyance direction of the contact region N and the discharge roll 71. On the other hand, on the downstream side in the transport direction of the discharge roll 71, the recording medium is pushed up in the Z-axis positive direction by the roll members 722L and 722R, as in the recording medium B4 in FIG. Shape. As a result, in the portion of the recording medium B4 positioned downstream in the transport direction of the discharge roll 71, streaks having components in the transport direction are generated at both ends in the width direction, while the recording medium B4 positioned upstream. Such a streak does not occur in the part (rear end). Accordingly, the rigidity of the portion of the recording medium B4 positioned on the downstream side in the transport direction of the discharge roll 71 is increased, and the rigidity of the portion of the recording medium B4 positioned on the upstream side in the transport direction of the discharge roll 71 is increased. It will not be in the state. In this case, the contact force between the guide member 55 and the recording medium B4 is reduced as compared with an image forming apparatus including the conventional discharge device 90, and the rubbing on the recording medium B4 is suppressed. Further, since the recording medium B4 is discharged to the medium receiving portion 80 in a state where the rigidity is increased, the recording medium B4 is stacked and accommodated on the medium receiving portion 80 in a straight posture along the transport direction.

  Returning to FIG. The drive mechanism 73 includes a drive unit 731, arms 732 </ b> L and 732 </ b> R, and a gear 733. The arm 732L and the arm 732R are provided with teeth (not shown). The arm 732L and the arm 732R are provided such that the longitudinal direction thereof is along the width direction of the recording medium, and a gear 733 is provided therebetween. The teeth of the arms 732L and 732R are meshed with the teeth of the gear 733. The drive unit 731 is, for example, an actuator, and moves the arm 732R in the width direction of the recording medium according to the control of the control unit 10. With this configuration, when the drive unit 731 moves the arm 732R in the width direction of the recording medium, the gear 733 rotates with the movement, and the arm 732L is opposite to the arm 732R with the rotation of the gear 733. It is moved in the direction of. The arm 732L is provided with a support member 723L for the contact roll 72L, and the arm 732R is provided with a support member 723R for the contact roll 72R. Therefore, the control unit 10 controls the drive unit 731 to move the positions of the roll member 722L provided on the support member 723L and the roll member 722R provided on the support member 723R.

  A positioning table 11 is stored in the memory of the control unit 10. The control unit 10 controls the drive unit 731 based on information described in the positioning table 11. FIG. 6 is a diagram illustrating an example of the positioning table 11. In the positioning table 11, “the size of the recording medium” and “the position of the roll member” are described in association with each other. “Size of recording medium” is information indicating the size of the recording medium on which an image is formed by the image forming unit 60, such as JIS (Japanese Industrial Standards) standards A3 and A4. “Position of roll member” is information representing the position of the roll member 722 according to the size of the recording medium ejected by the ejection device 70. For example, in the positioning table 11, the size “A4” of the recording medium and the position “position B” of the roll member 722 are associated with each other. This indicates that the roll members 722L and 722R are moved to the position B when the size of the recording medium discharged by the discharge device 70 is A4. Further, in this positioning table 11, the size “A3” of the recording medium is associated with the position “position A” of the roll member 722. This indicates that when the size of the recording medium ejected by the ejection device 70 is A3, the roll members 722L and 722R are moved to a position A indicating a position different from the previous position A.

  Here, an operation in which the control unit 10 controls the drive unit 731 of the drive mechanism 73 will be described. First, it is assumed that the user of the image forming apparatus 1 operates the display operation unit 30 and inputs an instruction for forming an image corresponding to image data on an A4 size recording medium. The control unit 10 determines that the attribute of the recording medium on which an image is formed by the image forming unit 60 is, for example, A4 size based on the operation signal supplied from the display operation unit 30. Then, the control unit 10 controls each unit of the image forming apparatus 1 to form an image on an A4 size recording medium. Subsequently, the control unit 10 determines the position to which the roll member 722 is moved based on the size of the recording medium included in the operation signal and the contents of the positioning table 11 stored in the memory. In this case, the control unit 10 specifies the “position of the roll member 722” associated with the size “A4” in the positioning table 11 illustrated in FIG. 6, and sets the movement destination position of the roll member 722 to the position B. decide. Then, the control unit 10 controls the driving unit 731 to move the position of the roll member 722 to the position B. That is, the drive unit 731 and the control unit 10 are an example of a moving unit that moves the contact member to a position corresponding to the determination result. Similarly, when the user of the image forming apparatus 1 operates the display operation unit 30 and inputs an instruction to form an image corresponding to image data on an A3 size recording medium, the control unit 10 Then, in the positioning table 11, the “position of the roll member 722” associated with the size “A3” is specified, and the position of the movement destination of the roll member 722 is determined as the position A. Then, the control unit 10 controls the driving unit 731 to move the position of the roll member 722 to the position B.

  FIG. 7 is a diagram of the discharge device 70 viewed from the positive direction of the Z axis, and is a diagram illustrating the relationship between the size of the recording medium and the position of the roll member. 7A shows the A4 size recording medium B61 and the roll members 722L and 722R moved to the position B. FIG. 7B shows the A3 size recording medium B62 and the position A. Roll members 722L and 722R are shown. As shown in the figure, the control unit 10 moves the positions of the roll members 722L and 722R according to the size of the recording medium, so that the roll members 722L and 722R come into contact with both ends in the width direction of the recording medium. Are arranged as follows. That is, even when the recording medium is different in size, the recording medium is discharged to the medium receiving portion 80 in a state where both end portions in the width direction are pushed up by the roll members 722L and 722R in a direction perpendicular to the transport direction. Even in this case, a streak having a component in the transport direction is generated in the portion of the recording medium located on the downstream side in the transport direction of the discharge roller 71, while the transport direction is present in the portion of the recording medium located on the upstream side. There is no streak with any component. Therefore, the recording medium is in a state where the rigidity of the portion located on the downstream side in the conveyance direction of the discharge roll 71 is increased, and the rigidity of the portion located on the upstream side in the conveyance direction of the discharge roll 71 is not increased. . The recording medium with increased rigidity is discharged to the medium receiving unit 80 in a state in which the curl at the time of image formation and the curl by the rollers constituting the conveyance unit are corrected, and thus the recording medium sequentially overlaps the medium receiving unit 80. Will be discharged. According to this configuration, the ejection device 70 changes the degree of rubbing on the recording medium to be ejected according to the attribute and size of the recording medium. Here, the positional relationship between the contact area N of the discharge roll 71 and the contact roll 72 will be described in detail.

  FIG. 8 is a view for explaining the contact area N of the discharge roll 71 and the position of the roll member 722 of the contact roll 72. As shown in FIG. 8A, in the contact region N between the roll member 712U and the roll member 712L, as viewed from the X-axis positive direction, the position of the end portion P93 in the Y-axis negative direction of the contact region N and the roll member It is desirable that the dimension ΔL2 in the Y-axis direction between the position of the end portion P94 in the Y-axis positive direction of 722L is as short as possible. Similarly, as shown in FIG. 8B, in the contact area N between the roll member 712U and the roll member 712L, as viewed from the X-axis positive direction, the position of the end portion P91 in the Y-axis positive direction of the contact area N The dimension ΔL1 in the Y-axis direction between the roll member 722R and the position of the end portion P92 in the Y-axis negative direction is preferably as short as possible. Thus, when the dimensions ΔL1 and ΔL2 are short, the rigidity of the recording medium is higher than when the dimensions ΔL1 and ΔL2 are long. The minimum value of the dimensions ΔL1 and ΔL2 is “0”. Further, it is desirable that the dimension in the X-axis direction between the position where the contact roll 72 is provided and the position where the discharge roll 71 is provided is as short as possible when viewed from the positive direction of the Y-axis. When the length in the X-axis direction is short, the rigidity of the recording medium is higher than when the length is long. In FIG. 8, a gap is provided between the roll member 712 </ b> U and the roll member 712 </ b> L. However, in reality, no gap is provided, and the roll member 712 </ b> U and the roll member 712 </ b> L come into contact with each other. Region N is formed.

[Comparison with conventional example]
For each of the image forming apparatus 1 in this embodiment and the image forming apparatus provided with the conventional discharge device 90, the contact force between the guide member and the recording medium was calculated by a simulator. The comparison result will be described with reference to FIG. FIG. 9 is a graph showing a comparison result with the conventional example regarding the contact force between the guide member and the recording medium. In this simulation, the amount by which a part of the roll member 722 protrudes in the Z-axis direction from the tangential plane D1 (hereinafter referred to as the protrusion amount) is 5 mm, and the physical properties of the recording medium are Young's modulus 1000 MPa and thickness 0.08 mm. It was. In the figure, E71 indicates the contact force in the configuration of the present embodiment, and E72 indicates the contact force in the conventional configuration. In this configuration, it is confirmed by simulation that the recording medium has sufficient rigidity at the time of ejection, and that the storage performance is not deteriorated by curling the recording medium.

  As shown in the figure, in the image forming apparatus provided with the discharge device 90, the contact force between the guide member and the recording medium is about 0.7N to 1.6N (average of about 1.2N). The value is shown. In the image forming apparatus 1 according to the present embodiment, the contact force between the guide member and the recording medium has a value of approximately 0.0N. Therefore, in the image forming apparatus 1 of the present embodiment, the contact force between the guide member and the recording medium is smaller than that of the image forming apparatus including the discharge device 90, and the rubbing on the recording medium is suppressed. ing.

<Modification>
The contents of the above-described embodiment may be modified as follows. Each modification shown below may be implemented in combination as necessary.
[Modification 1]
In the above embodiment, a part of the roll member 722 is provided so as to protrude in the positive Z-axis direction from the tangential plane D1, but conversely, a part of the roll member 722 is negative in the Z-axis direction from the tangential plane D1. It may be provided protruding in the direction. Specifically, as illustrated in FIG. 10B, the end P81 in the negative Z-axis direction of the roll member 722Ra is located in the negative Z-axis direction with respect to the contact region N. Further, the midpoint P83 of the straight line connecting the position of the end portion P81 in the negative Z-axis direction of the roll member 722Ra and the position of the end portion P82 in the positive Z-axis direction is located in the positive Z-axis direction from the contact area N. To do. In addition, as with the roll member 722Ra, a part of the roll member 722La is located in the negative Z-axis direction with respect to the contact region N. According to this configuration, the recording medium is curved along the guide member 55 on the upstream side in the conveyance direction of the contact region N and the discharge roll 71. On the other hand, on the downstream side in the transport direction of the discharge roll 71, both ends in the width direction of the recording medium are pushed down in the negative Z-axis direction by the roll members 722La and 722Ra, as in the recording medium B8 in FIG. Shape. As a result, the recording medium is in a state of increased rigidity as in the case where the recording medium is pushed up in the positive direction of the Z-axis. In FIG. 10B, a gap is provided between the roll member 712U and the roll member 712L, but in reality, no gap is provided, and the roll member 712U and the roll member 712L are in contact with each other. Thus, the contact region N is formed.

[Modification 2]
In the above-described embodiment, the “recording medium size” and the “position of the roll member 722” are described in the positioning table 11 in association with each other, but the position of the roll member 722 is specified. This information is not limited to this. FIG. 11 is a diagram showing an example of the positioning table 11a. In the positioning table 11a, “type of recording medium” is described in addition to “size of recording medium” and “position of roll member 722”. “Type of recording medium” is an example of the material of the recording medium, and is information indicating the Young's modulus and thickness of the recording member. The “position of the roll member 722” is information indicating the position of the roll member 722 determined according to the size and type of the recording medium ejected by the ejection device 70.

  For example, the recording table size “A3”, the recording medium type “type A1”, and the roll member position “position A1” are associated with the positioning table 11a. This indicates that the roll members 722L and 722R are moved to the position A1 when the size of the recording medium discharged by the discharge device 70 is A3 and the type thereof is type A1. The positioning table 11a is associated with the recording medium size “A3”, the recording medium type “type A2”, and the roll member position “position A2”. This indicates that the roll members 722L and 722R are moved to the position A1 when the size of the recording medium discharged by the discharge device 70 is A3 and the type thereof is type A1. In order to obtain a desired rigidity with respect to the recording medium, the positions of the roll members 722L and 722R may be determined in consideration of not only the size of the recording medium but also materials such as Young's modulus and thickness thereof. According to this configuration, the discharge device 70 changes the degree of rubbing on the discharged recording medium according to the material of the recording medium.

[Modification 3]
In the above embodiment, the drive mechanism 73 uses the drive unit 731, the arms 732 </ b> L and 732 </ b> R, and the gear 733 as means for moving the roll member 722. Any means may be used as long as the means moves 222L in the width direction of the recording medium.

[Modification 4]
In the above embodiment, the roll member 722 is an elliptical member when viewed from the X-axis positive direction and the Z-axis positive direction, but is not limited to this shape, and may be, for example, a cylinder or a cone. Good. In this case, the roll member 722 should just be provided in the rotating shaft 721 of the contact roll 72 so that it may become a circular shape seeing from the Y-axis direction. However, when the roll member 722 is an elliptical member when viewed from the positive direction of the X-axis, the corners of the roll member 722 are rounded compared to other shape members. This makes it difficult for folds and wrinkles to occur. Further, a so-called spring in which a wire is spirally wound may be used as the roll member 722. In this case, the spring may not be an elastic body.

[Modification 5]
In the above embodiment, the roll member 722 of the contact roll 72 rotates around the rotation shaft 721, but is not limited thereto, and may be configured not to rotate around the rotation shaft 721, for example. However, when the roll member 722 is configured not to rotate about the rotation shaft 721, the resistance due to contact with the recording medium is larger than when the contact member rotates.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus, 10 ... Control part, 11, 11a ... Table, 20 ... Communication part, 30 ... Display operation part, 40 ... Supply part, 50 ... Conveyance part, 55 ... Guide member, 60 ... Image forming part, 61 DESCRIPTION OF SYMBOLS ... Photosensitive unit, 62 ... Exposure part, 63 ... Belt unit, 631 ... Intermediate transfer belt, 632 ... Primary transfer roll, 633-637 ... Support roll, 638 ... Secondary transfer roll, 64 ... Fixing part, 70 ... Discharge device 71, 71L, 71R ... discharge roll, 711, 711L, 711U ... rotating shaft, 712, 712L, 712U ... roll member, 72, 72L, 72R ... contact roll, 721, 721L, 721R ... rotating shaft, 722, 722L, 722R ... roll member, 723, 723L, 723R ... support member, 73 ... drive mechanism, 731 ... drive unit, 732, 732L, 732R ... arm, 7 3 ... gear, D1 ... tangent plane.

Claims (7)

Conveying means for conveying the recording medium;
A guide member that contacts the recording medium conveyed by the conveying means and guides the recording medium in a direction approaching a discharge position at which the recording medium is discharged;
A plurality of roll pairs each having two rolls whose outer peripheries are in contact with each other and rotating around a rotation axis, wherein the recording medium guided by the guide member is sandwiched between contact areas of the two rolls; A plurality of roll pairs for discharging the recording medium to the discharge position;
A recording medium that is provided downstream of the plurality of roll pairs in the conveyance direction of the recording medium and closer to both ends of the rotating shaft than at least one of the contact areas, and is discharged by the pair of rolls. Two contact members that come into contact with each other, the contact members having a portion that intersects a tangent plane including a tangent line in each of the contact regions of the plurality of roll pairs when viewed from a direction along the rotation axis. A discharge device comprising: The discharging apparatus according to claim 1, wherein the contact member rotates in contact with a recording medium discharged by the pair of rolls. The discharging device according to claim 2, wherein the contact member has a portion whose roll diameter decreases as the roll diameter approaches the plurality of roll pairs. An image forming unit that forms an image on the recording medium by transferring the image according to the image data to the recording medium and fixing the image by heating and pressing;
An image forming apparatus comprising: the discharge device according to any one of claims 1 to 3, wherein the recording medium on which an image is formed by the image forming unit is conveyed and discharged to a discharge position. Determining means for determining an attribute of a recording medium on which an image is formed by the image forming means;
The image forming apparatus according to claim 4, further comprising: a moving unit that moves the contact member of the discharge device to a position according to a determination result by the determination unit. The image forming apparatus according to claim 5, wherein the attribute of the recording medium is a size of the recording medium. The image forming apparatus according to claim 5, wherein the attribute of the recording medium is a material of the recording medium.

Images