JP5879808B2 - Conveying apparatus and image forming apparatus - Google Patents

Description

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

  In Patent Document 1, as shown in FIG. 2, even if the recording material (14) fed to the transfer portion (N) is a strong one (thick paper), image transfer is performed without transfer omission. In addition, a part or all of the recording material guide member (16, 17) that receives the recording material (14) fed from the paper feeding unit and guides it to the transfer unit (N) is scraped by the recording material (14). It is disclosed that it is configured to move according to the strength of the.

  In Patent Document 2, as shown in FIG. 3, the transfer material (P) is used so that a high-quality image is formed on the various transfer materials (P) at a slight strength without toner dust and transfer deviation. It is disclosed that the guide member (32) for guiding toward the transfer position (TR) is an elastic body.

JP-A-6-348152 JP 2008-3445 A

  It is an object of the present invention to provide a transport device that can select a rushing posture of a recording medium into a transfer unit as compared with the prior art.

The conveyance device according to claim 1 includes a plurality of conveyance paths for conveying a recording medium toward a transfer portion formed by sandwiching a transfer belt between two opposing clamping members, and the plurality of conveyance paths among the plurality of conveyance paths. Switching means for switching a conveyance path through which the recording medium passes, and the plurality of conveyance paths are formed as a multilayer structure by arranging a plurality of plate-like members at intervals in the direction of gravity. The upstream end of the plate-like member that divides the plurality of conveyance paths among the sheet-like members in the conveyance direction of the recording medium is orthogonal to the conveyance direction of the recording medium when the plate-like member is viewed from the surface side. It is inclined with respect to the direction of
The conveying device according to claim 2 is the conveying device according to claim 1, wherein the switching unit causes the recording medium to bend due to gravity, and the plurality of conveying paths according to the amount of bending generated in the recording medium. Among these, the conveyance path through which the recording medium passes is switched.
According to a third aspect of the present invention, there is provided a transport device comprising: a plurality of transport paths for transporting a recording medium toward a transfer portion formed by sandwiching a transfer belt between two opposing clamping members; Switching means for switching a conveyance path through which the recording medium passes, and the plurality of conveyance paths are formed as a multilayer structure by arranging a plurality of plate-like members arranged in the gravity direction at intervals. The plate-like member disposed closest to the transfer belt among the plurality of plate-like members has a length shorter on one side of the transfer portion than the other plate-like members, and the switching means Is arranged at the lower side in the gravitational direction than the end of the plate-like member arranged closest to the transfer belt in the conveying direction of the recording medium and at the upper side in the gravitational direction from the other plate-like members. , Gravity on the recording medium That the deflection is generated, it switches the conveying path through which the recording medium among the plurality of transport paths in accordance with the amount of deflection which occurs in the recording medium.
A conveying device according to a fourth aspect is the conveying device according to the third aspect, wherein a plate-like member arranged closest to the transfer belt among the plurality of plate-like members is arranged in parallel to the transfer belt. ing.
According to a fifth aspect of the present invention, there is provided a transport device including a plurality of transport paths for transporting a recording medium toward a transfer unit formed by sandwiching a transfer belt between two opposing sandwiching members, and among the plurality of transport paths. Switching means for switching a conveyance path through which the recording medium passes, and the plurality of conveyance paths are formed as a multilayer structure by arranging a plurality of plate-like members arranged in the gravity direction at intervals. The plate-like member arranged closest to the transfer belt among the plurality of plate-like members is arranged in parallel to the transfer belt, and the switching means is closest to the transfer belt. The plate-like member to be arranged is arranged at the lower side in the gravity direction than the upstream end of the recording medium in the conveyance direction of the recording medium and at the upper side in the gravity direction of the other plate-like members, and the recording medium is bent due to gravity. Let Serial switches the conveying path in which the recording medium passes out of the plurality of transport paths in accordance with the amount of deflection which occurs in the recording medium.
The transport apparatus according to claim 6 is the transport apparatus according to any one of claims 2 to 5, wherein the switching unit causes the recording medium to bend due to gravity, and a recording medium having a smaller amount of bend is generated. The conveyance path through which the recording medium passes is switched among the plurality of conveyance paths so as to pass through the conveyance path approaching the transfer belt.
A transport apparatus according to a seventh aspect of the present invention is the transport apparatus according to any one of the second to sixth aspects, further comprising an amplifying unit that amplifies the amount of deflection generated in the recording medium.
The conveyance device according to claim 8 is the conveyance device according to any one of claims 1 to 7, wherein the recording medium is conveyed by a plate-like member that divides the plurality of conveyance paths among the plurality of plate-like members. An elastic member is attached to the upstream end in the direction so as to protrude upstream.
The image forming apparatus according to claim 9 is developed by the image holding member on which an electrostatic latent image is formed, a developing device that develops the electrostatic latent image formed on the image holding member with toner, and the developing device. A transfer device that transfers a toner image to a recording medium, and a transport device according to claim 1 that transports the recording medium toward a transfer portion of the transfer device.
The transport device of the first aspect includes a plurality of transport paths for transporting a recording medium toward a transfer portion formed by sandwiching a transfer belt between two opposing clamping members, and among the plurality of transport paths, And switching means for switching a conveyance path through which the recording medium passes.

Conveying apparatus of the second aspect, in the conveyance apparatus of the first aspect, said switching means, said recording medium deflection due to gravity is generated, out of the plurality of transport paths in accordance with the amount of deflection which occurs in the recording medium The conveyance path through which the recording medium passes is switched.

The conveying device according to a third aspect is the conveying device according to the first aspect , wherein the switching unit causes the recording medium to bend due to gravity, and the smaller the amount of bending that is generated, the closer to the transfer belt the recording medium is. The conveyance path through which the recording medium passes is switched among the plurality of conveyance paths so as to pass.

The transport device according to a fourth aspect is characterized in that in the transport device according to the second aspect or the third aspect , the transport device further includes an amplifying unit that amplifies a deflection amount generated in the recording medium.

Conveying apparatus of the fifth aspect, in the conveyance apparatus of any one aspect of the first to fourth embodiments, the plurality of transport paths, a multilayer structure by a plurality of plate members are arranged at intervals in the direction of gravity It is formed.

The conveying device according to a sixth aspect is the conveying device according to the fifth aspect , wherein the upstream end in the conveying direction of the recording medium of the plate-shaped member that divides the plurality of conveying paths among the plurality of plate-shaped members is When the plate member is viewed from the surface side, the plate member is inclined with respect to a direction orthogonal to the conveyance direction of the recording medium.

Conveying apparatus of the seventh aspect, in the conveyance apparatus of the fifth embodiment, the upstream end in the conveying direction of the recording medium of the plate member for dividing the plurality of transport path of the plurality of plate members, The elastic member is attached so as to protrude upstream.

Conveying apparatus of the eighth aspect, in the conveyance apparatus of any one aspect of the fifth to seventh aspect, the plate-like member arranged closest to the transfer belt of the plurality of plate-like member, other plate The length is shortened on one side of the transfer portion as compared with the shaped member.

Conveying apparatus of the ninth aspect, in the conveyance apparatus of any one aspect of the fifth to eighth aspect, the plate-like member arranged closest to the transfer belt of the plurality of plate-like member, the transfer belt It is characterized by being arranged in parallel to.

The image forming apparatus of the tenth aspect, the image carrier on which an electrostatic latent image is formed, a developing device for developing an electrostatic latent image formed on the image carrier with toner, which is developed by the developing device and having a transfer device for transferring the toner image to the recording medium, and a conveying device according to any one aspect of the first to ninth aspects for conveying the recording medium to a transfer portion of the transfer device.

According to the conveying apparatus according to 請 Motomeko 1, 3 and 5 and the first embodiment, if it is not configured to switch the conveying path of the recording medium passes through comprises a plurality of transport path for transporting the recording medium to the transfer unit In comparison with this, it is possible to select the posture of the recording medium entering the transfer portion.

According to the transport apparatus according to 請 Motomeko 2, 3 and 5 and the second embodiment, through which a recording medium among the plurality of transport paths in accordance with the amount of deflection which occurs in the recording medium deflection due to gravity is generated in the recording medium Compared to the case where the conveyance path is not switched, the conveyance path through which the recording medium passes can be switched using the bending generated in the recording medium.

According to the transport apparatus according to 請 Motomeko 6 and the third embodiment, a plurality of transport path so as to pass through the conveyance path approaches the transfer belt as the recording medium amount is small deflection that occurs to generate deflection due to gravity on the recording medium As compared with the case where the conveyance path through which the recording medium passes is not switched, the rush impact to the transfer portion of the recording medium (for example, a heavy thick paper) having a small amount of bending can be reduced.

According to the transport apparatus according to 請 Motomeko 7 and fourth aspect, as compared with the case having no amplifying means for amplifying the amount of deflection occurring in a recording medium, for switching the conveyance path of the recording medium passes more accurately be able to.

According to the transport apparatus according to 請 Motomeko 1, 3 and 5 as well as the fifth embodiment, compared with the case not configured to form a plurality of transport paths as a multilayer structure by a plurality of plate members are arranged at intervals Thus, a plurality of transport paths can be formed with a simple configuration.

According to the transport apparatus according to 請 Motomeko 1 and sixth aspects, a plurality of plate-shaped upstream end plate-like member in the transport direction of the recording medium of the plate member for dividing a plurality of transport paths of the member When viewed from the surface side, the impact when the recording medium collides with a plate-like member that is divided into a plurality of conveyance paths is reduced compared to the case where the recording medium is not inclined with respect to the direction perpendicular to the conveyance direction of the recording medium. can do.

According to the transport apparatus according to 請 Motomeko 8 and the seventh embodiment, the elastic member to the upstream end in the conveying direction of the plate-like member of a recording medium for dividing a plurality of transport paths of the plurality of plate members Compared to the case where the recording medium does not protrude so as to protrude upstream, the impact when the recording medium collides with a plate-like member divided into a plurality of transport paths can be reduced.

According to the transport apparatus according to 請 Motomeko 3 and the eighth aspect, one transfer unit plate member which is disposed closest to the transfer belt of the plurality of plate members as compared with the other plate-like member Compared to the case where the length is not shortened on the side, it is possible to suppress the transfer failure at the transfer portion due to the impact that occurs when the recording medium (particularly strong heavy paper) passes through the transport path.

According to the transport apparatus according to 請 Motomeko 4 and ninth embodiments, when the plate-like member arranged closest to the transfer belt of the plurality of plate-like member is not disposed parallel to the transfer belt In comparison with this, it is possible to suppress an impact when the recording medium enters the transfer portion.

According to the image forming apparatus according to 請 Motomeko ninth and tenth aspect, when no transport apparatus according to any one aspect of any one or first to ninth aspect of claims 1-8 Compared to this, an image with good image quality can be formed.

1 is a diagram illustrating an example of a configuration of an image forming apparatus including a transport device according to a first embodiment of the present invention. It is a figure which shows the structure of the vicinity of the conveyance path of the conveying apparatus shown in FIG. It is a figure which shows the structure of the vicinity of the conveyance path of the conveying apparatus shown in FIG. It is a figure which shows the structure of the vicinity of the conveyance path of the conveying apparatus of 2nd Embodiment of this invention. It is a figure which shows the structure of the vicinity of the conveyance path of the conveying apparatus of 2nd Embodiment of this invention. It is a figure which shows the structure of another aspect of the conveying apparatus shown in FIG. It is a figure which shows the structure of another aspect of the conveying apparatus shown in FIG. It is a figure which shows the structure at the time of seeing the center plate-shaped member shown in FIG. 5 from the surface side. It is a figure which shows the structure of another aspect of the center plate-shaped member shown in FIG. It is a figure which shows the structure of another aspect of the center plate-shaped member shown in FIG. FIG. 5 is a diagram illustrating an aspect when recording paper P is supplied to a secondary transfer unit through an upper conveyance path in the conveyance device illustrated in FIG. 4. FIG. 5 is a diagram illustrating a state before and after the recording paper P passes through the upper transport path when the recording paper P is supplied to the secondary transfer unit through the upper transport path in the transport device illustrated in FIG. 4. FIG. 12A is a diagram showing a mode immediately before passing through. FIG. 12B is a diagram showing a mode immediately after passing through.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a conveying device and an image forming apparatus according to the present invention will be described below with reference to the accompanying drawings.

-First embodiment-
First, a first embodiment of a transport device according to the present invention will be described.

(Image forming device)
FIG. 1 shows an example of the configuration of an image forming apparatus including a transport apparatus according to the first embodiment of the present invention. In addition, the arrow Z in a figure shows the gravity direction, and the arrow X, the arrow Y, and the arrow Z have shown the direction orthogonal to each other.

  The image forming apparatus 1 includes four image forming units 10Y, 10M, 10C, and 10K (Y is for yellow, M is for magenta, C is for cyan, and K is for black), a transfer device 30, and a conveyance A device 40 and a fixing device 50 are provided.

  Each of the image forming units 10Y, 10M, 10C, and 10K includes photosensitive drums 12Y, 12M, 12C, and 12K, which are examples of image carriers. Each of the photosensitive drums 12Y, 12M, 12C, and 12K is rotatable in a direction indicated by an arrow A in the drawing.

  Around the photosensitive drums 12Y, 12M, 12C, and 12K, charging devices 14Y, 14M, 14C, and 14K for charging the surfaces of the photosensitive drums 12Y, 12M, 12C, and 12K, and the charged photosensitive drum 12Y, respectively. , 12M, 12C, and 12K, and exposure devices 16Y, 16M, 16C, and 16K that expose the surface to form electrostatic latent images based on image data, and the surfaces of the photosensitive drums 12Y, 12M, 12C, and 12K. Developing devices 18Y, 18M, 18C, and 18K that use the toner contained in the developer as the electrostatic latent image formed on the toner, and a primary transfer roll 20Y for primary transfer of the toner image to the transfer belt 100, 20M, 20C, 20K and the feeling for removing the toner remaining on the surface of the photosensitive drums 12Y, 12M, 12C, 12K after the primary transfer. Body drum cleaner 22Y, 22M, 22C, are arranged and 22K.

  The transfer device 30 includes an endless transfer belt 100. The transfer belt 100 is supported by a tension applied from the inner peripheral surface side by the support rolls 26a, 26b, and 26d, the primary transfer rolls 20Y, 20M, 20C, and 20K, the tension / steering roll 26c, and the backup roll 28 (stretching). It can be rotated in a direction indicated by an arrow B in the figure by a drive source (not shown) (for example, an electric motor). The tension / steering roll 26c has a function of preventing the transfer belt 100 from being distorted or meandering.

  The primary transfer rolls 20Y, 20M, 20C, and 20K are disposed to face the photoconductive drums 12Y, 12M, 12C, and 12K via the transfer belt 100, and are connected to the photoconductive drums 12Y, 12M, 12C, and 12K. The primary transfer portions 24Y, 24M, 24C, and 24K are formed by sandwiching the transfer belt 100 therebetween. Further, a secondary transfer roll 29 is disposed at a position facing the backup roll 28 via the transfer belt 100, and the transfer belt is constituted by the backup roll 28 and the secondary transfer roll 29 as an example of the sandwiching members facing each other. By sandwiching 100, a secondary transfer portion 31 as an example of a transfer portion is formed. A belt cleaner 32 is disposed downstream of the secondary transfer unit 31 in the rotation direction of the transfer belt 100, and toner remaining on the surface of the transfer belt 100 after the secondary transfer is removed. ing.

  The conveying device 40 is disposed upstream of the secondary transfer unit 31 in the rotation direction of the transfer belt 100 (on the left side of the secondary transfer unit 31 in FIG. 1), and is disposed in the secondary transfer unit 31 as an example of a recording medium. Recording paper P is supplied. The transport device 40 includes a tray 41 that stores recording paper P as an example of a recording medium, a pickup roller 42 that picks up the recording paper P from the tray 41 one by one, and a feed roll that feeds the recording paper P at a predetermined timing. 44 and a conveyance path 46 for conveying the recording paper P toward the secondary transfer unit 31. A specific configuration near the conveyance path 46 of the conveyance device 40 will be described later.

  The fixing device 50 is disposed downstream of the secondary transfer unit 31 in the rotation direction of the transfer belt 100 (on the right side of the secondary transfer unit in FIG. 1), and is recorded on the recording paper P conveyed by the belt type conveyance device 52. Is pressed to fix the toner image on the recording paper P as a permanent image.

  In the image forming apparatus 1, an image is formed as follows.

  First, in the image forming unit 10Y, the photosensitive drum 12Y rotates in the direction of arrow A (clockwise) in the drawing, and the surface thereof is charged by the charging device 14Y. Next, the charged surface of the photosensitive drum 12Y is exposed and scanned by the exposure device 16Y, whereby an electrostatic latent image of the first color (Y) is formed on the surface of the photosensitive drum 12Y.

  This electrostatic latent image is developed with toner (a developer containing toner) supplied by the developing device 18Y, and a visualized toner image is formed on the surface of the photoreceptor drum 12Y. The toner image reaches the primary transfer portion by the rotation of the photoreceptor drum 12Y, and is primarily transferred to the transfer belt 100 by applying a primary transfer voltage between the primary transfer roll 20Y and the photoreceptor drum 12Y. .

  Similarly, the second color toner image (M), the third color toner image (C), and the fourth color toner image (K) are formed by the image forming units 10M, 10C, and 10K and overlapped on the transfer belt 100. The images are sequentially transferred so as to be matched. Here, the rotations of the transfer belt 100 and the photosensitive drums 12Y, 12M, 12C, and 12K are synchronized so that the toner images of the respective colors do not shift. As a result, a multiple toner image is formed on the transfer belt 100.

  The multiple toner image transferred to the transfer belt 100 reaches the secondary transfer portion 31 by the rotation of the transfer belt 100. In the secondary transfer unit 31, a secondary transfer voltage is applied between the backup roll 28 and the secondary transfer roll 29, and the recording paper P supplied thereto is sandwiched together with the transfer belt 100, so that The toner image is secondarily transferred to the recording paper P.

  The recording paper P to which the multiple toner image has been transferred is conveyed to the fixing device 50 by the belt-type conveyance device 52, and the multiple toner image is fixed on the recording paper P by a heating and pressing process to be a permanent image.

  The transfer belt 100 after the transfer of the multiple toner image to the recording paper P is cleaned by the belt cleaner 32, and the toner remaining on the surface is removed. In addition, the surfaces of the photosensitive drums 12Y, 12M, 12C, and 12K are also cleaned by the photosensitive drum cleaners 22Y, 22M, 22C, and 22K, and toner remaining on the surfaces is removed.

  When forming a monochromatic image, the toner image formed by any of the image forming units 10Y, 10M, 10C, and 10K is primarily transferred to the transfer belt 100, and the monochromatic toner image is secondarily transferred to the recording paper P. To do.

(Conveying path of the conveying device)
Next, the configuration of the conveyance path 46 of the conveyance device 40 will be specifically described. 2 and 3 show a configuration in the vicinity of the conveyance path 46 of the conveyance device 40.

  As shown in FIGS. 2 and 3, in the transport apparatus 40, the transport path 46 has two transport paths for transporting the recording paper P toward the secondary transfer unit. The conveyance path 46 includes a switching plate 48 as an example of a switching unit that switches a conveyance path through which the recording paper P passes among the two conveyance paths.

  Specifically, the conveyance path 46 is one path on the upstream side in the conveyance direction of the recording paper P (indicated by an arrow C in the figure), but on the downstream side, the conveyance path 46 is bifurcated vertically into two paths in the gravity direction. ing. The switching plate 48 is provided at a position where the conveyance path branches from one path to two paths, and is provided on one of the upper conveyance path 54 located above and the lower conveyance path 56 located below. The other conveyance path is blocked so that the recording paper P passes (guides).

  When the recording paper P is supplied to the secondary transfer unit 31 by the conveying device 40, it is preferable that the recording paper P is brought as close as possible to the transfer belt 100 and is placed along the transfer belt 100 to the secondary transfer unit 31. The rush impact is reduced, which is preferable. In particular, when the recording paper P is a thick paper having a strong stiffness (high bending rigidity), the rush impact to the secondary transfer unit 31 is stronger than a thin paper having a weak stiffness (low bending rigidity). It is desirable to supply the sheet P to the secondary transfer unit 31 in a posture in which the sheet P is brought close to the transfer belt 100 and along the transfer belt 100.

  On the other hand, when the recording paper P is supplied to the secondary transfer unit 31 by the transport device 40, if the recording paper P is a thin thin paper, the paper posture is unstable as compared to a thick thick paper. Therefore, when the recording paper P is brought close to the transfer belt 100 and along the transfer belt 100, the recording paper P is attracted toward the transfer belt 100 by electrostatic force, and the toner image on the transfer belt 100 may be disturbed. (Factor of image quality degradation of the formed image). Therefore, when the recording paper P is a thin thin paper, it is desirable that the recording paper P is separated from the transfer belt 100 and supplied to the secondary transfer unit 31 so as not to follow the transfer belt.

  In view of this situation, as shown in FIG. 2, in the transport device 40, when supplying a thick heavy paper as the recording paper P to the secondary transfer unit 31, the switching plate 48 is switched downward to lower the transport path. 56 is sealed so that the recording paper P passes through the upper conveyance path 54. The recording paper P that has passed through the upper conveyance path 54 approaches the transfer belt 100 and is supplied to the secondary transfer unit 31 in a posture along the transfer belt 100 as indicated by an arrow D in the drawing. Therefore, the impact when the thick thick paper enters the secondary transfer portion 31 is reduced.

  On the other hand, as shown in FIG. 3, when supplying a weak thin paper as the recording paper P to the secondary transfer unit 31, the switching plate 48 is switched upward to block the upper conveyance path 54, and the recording paper P is moved downward. It is configured to pass through the conveyance path 56. The recording paper P that has passed through the lower conveyance path 56 is supplied to the secondary transfer unit 31 in a posture that is away from the transfer belt 100 and does not follow the transfer belt 100 as indicated by an arrow E in the drawing. Therefore, the toner image on the transfer belt 100 is prevented from being disturbed by the thin paper that is weakly sucked toward the transfer belt 100.

  As described above, in the transport device 40, two transport paths are provided in the transport path 46 for transporting the recording paper P toward the secondary transfer unit 31, and the recording paper P is the second transport path. It was configured to switch the transport route. Therefore, it is possible to select (change) the entry posture of the recording paper P into the secondary transfer unit 31. That is, by selecting (changing) the entry posture of the recording paper P into the secondary transfer unit 31 according to the strength of the recording paper P, the image forming apparatus 1 can form an image with good image quality.

  Note that the switching of the switching plate 48 may be performed manually by an operation switch (not shown) provided in the image forming apparatus 1 (by inputting the type of the recording paper P), or the recording paper A detecting means (not shown) for detecting the strength of P may be provided so as to be automatically performed according to the detection result.

  Further, when the recording paper P is wound (curled), the conveyance path through which the recording paper P passes may be switched according to the direction and size of the winding. Further, since the winding state generated on the recording paper P is different between the single-sided printing and the double-sided printing, the conveyance path through which the recording paper P passes may be switched between the single-sided printing and the double-sided printing.

  Further, in the transport apparatus 40, two transport paths are provided. However, switching is possible so that the recording paper P passes through one of the three or more transport paths while providing three or more paths. You may comprise so that a means may be provided.

-Second Embodiment-
Next, a second embodiment of the transport device according to the present invention will be described. In addition, the same code | symbol is attached | subjected to the structure same as 1st Embodiment.

  4 and 5 show a configuration in the vicinity of the conveyance path 82 of the conveyance device 80 as the second embodiment of the conveyance device according to the present invention.

  As shown in FIGS. 4 and 5, in the transport path 82 of the transport apparatus 80, the two transport paths have a multilayer structure in which three plate-like members 84, 86, 88 are arranged at intervals in the direction of gravity. It is formed as. An upper plate-like member (a plate-like member arranged closest to the transfer belt) 84 is arranged in parallel to the transfer belt 100, and a central plate-like member 86 and a lower plate-like member 88. Compared to FIG. 4, the length is shortened on one side of the secondary transfer portion 31. The central plate-like member 86 is a member that divides the two conveyance paths. The lower plate-shaped member 88 is disposed so as to incline upward from the upstream side to the downstream side in the conveyance direction of the recording paper P. Thus, two conveyance paths are formed by a simple configuration in which three plate-like members 84, 86, 88 are arranged.

  Further, in the conveying device 80, as a switching means in place of the switching plate 48 in the first embodiment, the recording paper P is bent due to gravity, and the recording paper P passes through according to the amount of bending generated in the recording paper P. A bending generation switching unit 90 for switching the path is provided. Specifically, the bend generation switching unit 90 supports the recording paper P in a cantilever manner by the upstream plate member 92 and the feed roll 44 on the upstream side of the two transport paths in the transport direction of the recording paper P. A space for bending the recording paper P by its own weight is formed.

  As shown in FIG. 4, when supplying a strong thick paper as the recording paper P to the secondary transfer unit 31, when the recording paper P is supported in a cantilevered state, the deflection generation switching unit 90 applies the recording paper P to the recording paper P. The amount of bending that occurs is relatively small, so that the recording paper P passes through the upper conveyance path 54. On the other hand, as shown in FIG. 5, when supplying a thin thin paper as the recording paper P to the secondary transfer unit 31, when the recording paper P is supported in a cantilever manner, the flexure generation switching unit 90 records the recording paper. The amount of deflection generated in P is relatively large, so that the recording paper P passes through the lower conveyance path 56.

  As described above, in the transport device 80, when the recording paper P is supplied to the secondary transfer unit 31, the bending generation switching unit 90 causes the recording paper P to bend due to gravity, and the amount of bending generated in the recording paper P is reduced. Accordingly, the conveyance path through which the recording paper P passes is switched. Specifically, the recording paper P having a smaller amount of deflection generated in the deflection generation switching unit 90 is configured to switch so as to pass through the upper conveyance path (conveyance path approaching the transfer belt 100).

  As shown in FIG. 6, the bending generation switching unit 90 is provided with a suction device 94 as an example of an amplifying unit that sucks the recording paper P from below so as to amplify the amount of bending generated in the recording paper P. Good. As a result, even if the amount of bending caused by only gravity is a relatively small amount of recording paper P, it is possible to pass the lower transport path 56 by amplifying the amount of bending. Therefore, for example, even for the recording paper P having a relatively small amount of bending caused only by gravity, it can be accurately guided to the transport path to be passed. Examples of the suction device 94 include those using electrostatic force and those using negative pressure. Further, as shown in FIG. 7, an elastic member (for example, a PET film (mylar)) 96 is provided as an amplifying unit in contact with the upper surface of the recording paper P instead of the suction device 94, and the amount of deflection generated in the recording paper P May be amplified.

  FIG. 8 shows a configuration when the central plate-like member 86 is viewed from the surface side. As shown in the figure, the central plate-like member 86 has a trapezoidal shape, and the upstream end 86a of the central plate-like member 86 in the conveyance direction of the recording paper P (indicated by the arrow C in the figure) is the recording paper P. Is inclined with respect to a direction (indicated by an arrow F in the figure) perpendicular to the conveying direction. Accordingly, even when the recording sheet P collides with the central plate member 86 that divides the two conveyance paths, the front end Pa of the recording sheet P and the end 86a of the central plate member are in line contact. Therefore, the impact at the time of collision is reduced. In other words, even when the recording paper P collides with the central plate-like member 86, the end Pa on the front side of the recording paper P and the end 86a of the central plate-like member are in point contact with each other. P is likely to be drawn into the transport path. Therefore, even when the recording paper P collides with the central plate-like member 86, the occurrence of paper jam is suppressed.

  As shown in FIG. 9, the central plate-like member 86 may be pentagonal, and the end 86 a of the central plate-like member 86 may be formed in a “V” shape. Further, as shown in FIG. 10, instead of inclining the end portion 86a of the central plate-shaped member 86, an elastic member (for example, PET film (mylar)) 98 is disposed upstream of the end portion 86a of the central plate-shaped member 86. You may make it provide so that it may protrude to the side.

  FIG. 11 shows an aspect in which the recording paper P is supplied to the secondary transfer unit 31 through the upper conveyance path 54. As described above, the upper plate member 84 is disposed in parallel to the transfer belt 100. Therefore, the recording paper P is supplied to the secondary transfer unit 31 in a posture along the transfer belt 100 as indicated by an arrow D in the drawing. Therefore, the impact when the recording paper P enters the secondary transfer portion 31 is suppressed.

  FIG. 12 shows a state before and after the recording paper P passes through the upper transport path 54 when the recording paper P is supplied to the secondary transfer unit 31 through the upper transport path 54. FIG. 12A shows a mode immediately before passing through, and FIG. 12B shows a mode immediately after passing through.

  Immediately before the recording sheet P passes through the upper conveyance path 54, a downward force (indicated by an arrow G in the figure) is applied to the recording sheet P from the upper plate-like member 84. Immediately after the recording paper P passes through the upper conveyance path 54, an impact is generated on the recording paper P due to the release of the downward force. This impact is transmitted to the secondary transfer section 31 through the recording paper P.

  Here, as described above, the upper plate-like member 84 is shorter on one side of the secondary transfer portion 31 than the central plate-like member 86 and the lower plate-like member 88. For this reason, the downward force acting on the recording sheet P immediately before the recording sheet P passes through the upper conveyance path 54 causes the length of the upper plate member 84 on the secondary transfer portion 31 side to be the central plate member 86 and Compared with the case where the lower plate-like member 88 is made to be the same level, it becomes smaller. Therefore, the impact generated when the recording paper P passes through the upper conveyance path 54 is reduced, and the impact transmitted to the secondary transfer unit 31 through the recording paper P is also reduced.

  In particular, when the recording paper P is a heavy thick paper, the downward force acting on the recording paper P and the impact generated when passing through the upper conveyance path 54 are large, and this impact is applied to the secondary transfer unit 31 through the recording paper P. The transfer failure due to the transmission becomes remarkable. Accordingly, the length of the upper plate-shaped member 84 on the secondary transfer portion 31 side in the upper conveyance path 54 through which strong thick paper passes as the recording paper P is formed short. As a result, transfer defects in the secondary transfer unit 31 due to an impact generated when a particularly strong recording paper P passes through the upper conveyance path 54 are suppressed.

  In the conveyance device 80 according to the second embodiment, three plate-like members 84, 86, and 88 are arranged to provide the conveyance path 82 having two paths. However, four or more plate-like members are arranged to have three or more paths. You may comprise so that a conveyance path may be provided.

  In the transport device 40 according to the first embodiment and the transport device 80 according to the second embodiment, the recording paper P is transported in the horizontal direction. However, the recording paper P is transported upward by a certain angle in the gravity direction. Even in this case, the present invention can be applied.

  Although the recording paper P has been described as an example of the recording medium, the present invention is applicable to other recording materials such as an OHP sheet.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 12 Photosensitive drum (an example of an image holding body)
14 Charging device 16 Exposure device 18 Developing device 20 Primary transfer roll 24 Primary transfer portion 28 Backup roll (an example of a clamping member)
29 Secondary transfer roll (an example of a clamping member)
30 Transfer Device 31 Secondary Transfer Unit (Example of Transfer Unit)
40 Conveying device 42 Pickup roller 44 Feed roll 46 Conveying path 48 Switching plate (an example of switching means)
54 Upper transfer path (one of multiple transfer paths)
56 Downward transfer path (one of multiple transfer paths)
56 downward conveyance path 80 conveyance apparatus 82 conveyance path 84 plate-like member 86 plate-like member 88 plate-like member 90 Deflection generation switching part (an example of switching means)
92 Upstream plate member 94 Suction machine (an example of amplification means)
98 Elastic member (an example of amplification means)
100 Transfer belt

Claims (9)

A plurality of conveyance paths for conveying the recording medium toward a transfer portion formed by sandwiching the transfer belt between two opposing clamping members;
Switching means for switching a conveyance path through which the recording medium passes among the plurality of conveyance paths;
I have a,
The plurality of transport paths are formed as a multilayer structure by arranging a plurality of plate-like members at intervals in the direction of gravity,
Of the plurality of plate-like members, the upstream end of the plate-like member that divides the plurality of conveyance paths in the conveyance direction of the recording medium is formed when the plate-like member is viewed from the surface side. A transport device that is inclined with respect to a direction orthogonal to the transport direction .   2. The transport according to claim 1, wherein the switching unit causes the recording medium to bend due to gravity, and switches a transport path through which the recording medium passes among the plurality of transport paths according to a bend amount generated in the recording medium. apparatus. A plurality of conveyance paths for conveying the recording medium toward a transfer portion formed by sandwiching the transfer belt between two opposing clamping members;
Switching means for switching a conveyance path through which the recording medium passes among the plurality of conveyance paths;
Have
The plurality of transport paths are formed as a multilayer structure by arranging a plurality of plate-like members that are three or more in the direction of gravity.
Of the plurality of plate-like members, the plate-like member arranged closest to the transfer belt is shortened on one side of the transfer portion compared to other plate-like members,
The switching means is located below the end of the plate-like member arranged closest to the transfer belt on the upstream side in the conveyance direction of the recording medium and above the other plate-like member in the gravity direction. A conveying device configured to cause the recording medium to bend due to gravity and switch a conveying path through which the recording medium passes among the plurality of conveying paths according to an amount of bending generated in the recording medium . The conveying device according to claim 3 , wherein a plate-like member that is arranged closest to the transfer belt among the plurality of plate-like members is arranged in parallel to the transfer belt . A plurality of conveyance paths for conveying the recording medium toward a transfer portion formed by sandwiching the transfer belt between two opposing clamping members;
Switching means for switching a conveyance path through which the recording medium passes among the plurality of conveyance paths;
Have
The plurality of transport paths are formed as a multilayer structure by arranging a plurality of plate-like members that are three or more in the direction of gravity.
Of the plurality of plate-like members, the plate-like member arranged closest to the transfer belt is arranged in parallel to the transfer belt,
The switching means is located below the end of the plate-like member arranged closest to the transfer belt on the upstream side in the conveyance direction of the recording medium and above the other plate-like member in the gravity direction. A conveying device configured to cause the recording medium to bend due to gravity and switch a conveying path through which the recording medium passes among the plurality of conveying paths according to an amount of bending generated in the recording medium . The switching unit causes the recording medium to bend due to gravity, and the recording medium passes through the plurality of transport paths so that a recording medium with a small amount of bending is passed through the transport path approaching the transfer belt. The conveyance apparatus of any one of Claims 2-5 which switches a conveyance path | route . Furthermore, the conveying apparatus of any one of Claims 2-6 which has an amplifying means which amplifies the deflection amount which generate | occur | produces in the said recording medium . The end portion of the upstream side in the conveying direction of the recording medium of the plate member for dividing the plurality of transport path of the plurality of plate members, according to claim 1 which is mounted so as to protrude the elastic member on the upstream side 8. The transfer device according to any one of items 7. An image carrier on which an electrostatic latent image is formed;
A developing device for developing the electrostatic latent image formed on the image carrier with toner;
A transfer device for transferring the toner image developed by the developing device to a recording medium;
The conveyance device according to any one of claims 1 to 8, wherein the recording medium is conveyed toward a transfer portion of the transfer device;
An image forming apparatus.

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