JP2021147175A - Sheet conveyance device and image formation apparatus - Google Patents

Abstract

To reduce impact sound due to a rear end curling that occurs because a rear end of a sheet pressed against a conveyance guide is suddenly repelled when the rear end of the sheet deformed into a waveform shape conveyed in a bent second conveyance path passes through a merging position where the bent second conveyance path merges with a first conveyance path.SOLUTION: A recording sheet 5 on which an unfixed toner image is fixed by a fixation device is discharged by a sheet discharge roll pair 61 through a linear discharge conveyance path 62. A recording sheet 5 that is discharged with the front and back inverted among the recording sheets 5 on which the unfixed toner images are fixed by the fixation device is discharged through a bent discharge conveyance path 66. At that time, a rear end 5a of the recording sheet 5 deformed into the waveform shape by the sheet discharge roll pair 61 and conveyed along the bent discharge conveyance path 66 is guided to the linear discharge conveyance path 62 by a support film 80.SELECTED DRAWING: Figure 8

Description

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

Conventionally, as a technique related to a sheet transfer device, for example, those disclosed in Patent Documents 1 to 3 and the like have already been proposed.

Patent Document 1 fixes a paper on which a toner image has been fixed by a fixing device, a delivery roller that sends out the paper to the outside of the machine while deforming the widthwise cross section of the paper into a waveform, and a paper that has advanced via the fixing device. It has a paper guide that guides along a curved guide path from the container to the delivery roller, and the paper guide is configured to have a cross-sectional shape that is almost the same as the paper shape that is deformed by the delivery roller. Is.

Patent Document 2 includes a paper guide member extending from a transport guide located at the center of the merging portion toward a curved transport path in the merging portion, and the extended tip portion of the paper guide member is inside the merging portion. It is configured so that it is arranged in a non-contact manner with respect to other transport guides.

Patent Document 3 provides a sheet material provided with a step merging portion where a first transport path for transporting the sheet material at a predetermined height and a second transport path for transporting the sheet material at a height lower than the first transport path merge. In the transport device, the central portion of the edge of the support surface that supports the sheet material in the first transport path at the step confluence is configured to have a concave shape recessed in the transport direction of the sheet material. be.

JP-A-2007-230746 Japanese Unexamined Patent Publication No. 2016-05006 Japanese Unexamined Patent Publication No. 2011-152960

An object of the present invention is to provide a curved second transport path as compared with the case where a paper guide member extending from a transport guide located at the center of the merging position toward a curved transport path in the merging position is provided. At the confluence position where it merges with the first transport path, when the rear end of the corrugated sheet that is transported along the curved second transport path passes, the rear end of the sheet that was pressed against the transport guide It is an object of the present invention to provide a sheet transport device and an image forming device capable of reducing an impact sound due to a rear end splash generated by being suddenly flipped.

According to the first aspect of the present invention, among the first and second transport paths for transporting sheets, the curved second transport path merges with the linear first transport path. A transport means that is arranged on the downstream side along the transport direction of the sheet and that deforms the sheet into a wavy shape by a plurality of roll pairs having different outer diameters along the direction intersecting the transport direction and transports the sheet.
The wave that is arranged from the second transport path toward the first transport path at the confluence position and protrudes toward the first transport path side of the sheet that is transported along the second transport path. A comb-shaped support means that supports the convex part of the shape,
It is a sheet transfer device provided with.

According to the second aspect of the present invention, the conveying means alternately arranges a first roll having a relatively large outer diameter and a second roll having a relatively small outer diameter along the axial direction. The sheet transport device according to claim 1.

The invention according to claim 3 is the sheet transport device according to claim 2, wherein the supporting means is arranged at a position corresponding to the second roll.

According to the fourth aspect of the present invention, the tip of the supporting means projects toward the first transport path side from a tangent line provided at the nip portion of the second roll in parallel with the first transport path. The sheet transport device according to claim 2, which is arranged in such a manner.

According to a fifth aspect of the present invention, the plurality of transport paths include a first transport path for transporting the sheet in a straight line and a second transport path for transporting the sheet in a curved state. Item 2. The sheet transport device according to item 1.

The invention according to claim 6 is the sheet transport device according to claim 5, wherein the support means is arranged in the second transport path.

The invention according to claim 7 is the sheet transport device according to claim 1, wherein the supporting means is made of a flexible film-like member.

The invention according to claim 8 is the sheet conveying device according to claim 7, wherein the supporting means is formed in a tapered shape and a curved tip toward the downstream side along the conveying direction of the sheet. be.

The invention according to claim 9 comprises an image forming means for forming an image on a sheet and an image forming means.
A sheet transporting means for transporting the sheet and
With
An image forming apparatus using the sheet conveying device according to any one of claims 1 to 8 as the sheet conveying means.

According to the first aspect of the present invention, the paper guide member is curved as compared with the case where the paper guide member extending from the transport guide located at the center of the merging position toward the curved transport path in the merging position is provided. At the confluence position where the second transport path merges with the first transport path, it is pressed against the transport guide when the rear end of the corrugated sheet that is transported through the curved second transport path passes through. It is possible to reduce the impact noise caused by the rear end splash generated when the rear end of the sheet is suddenly flipped.

According to the second aspect of the present invention, the conveying means alternately arranges the first roll having a relatively large outer diameter and the second roll having a relatively small outer diameter along the axial direction. It is possible to correct the posture of the seat and transport it as compared with the case where the seat is not provided.

According to the third aspect of the present invention, in the support means, the rear end of the corrugated sheet is in the first transport path as compared with the case where the support means is not arranged at the position corresponding to the second roll. It is possible to surely reduce the sound generated when hitting.

Compared to the invention according to claim 4, the support means has a first tip as compared with a case where the tip thereof does not protrude from a tangent line provided in parallel with the first transport path in the nip portion of the second roll. It is possible to reliably support the wavy convex portion protruding toward the transport path side.

According to the fifth aspect of the invention, the plurality of transport paths do not have a first transport path for transporting the sheet in a straight line and a second transport path for transporting the sheet in a curved state. It is possible to improve the degree of freedom when the sheet is conveyed by the conveying means.

According to the invention described in claim 6, the supporting means can suppress the hindrance of the sheet transported along the first transport path as compared with the case where the support means is not arranged in the second transport path.

According to the invention described in claim 7, the supporting means can be easily provided as compared with the case where the supporting means is not composed of a flexible film-like member.

According to the invention described in claim 8, the supporting means suppresses the supporting means from becoming an obstacle to the sheet transport as compared with the case where the width does not change toward the downstream side along the sheet transport direction. be able to.

According to the invention described in claim 9, the sound generated when the sheet is conveyed is reduced as compared with the case where the sheet conveying device according to any one of claims 1 to 8 is not used as the sheet conveying means. It becomes possible.

It is an overall block diagram which shows the image forming apparatus to which the paper ejecting apparatus which concerns on Embodiment 1 of this invention are applied. It is a block diagram which shows the paper ejecting apparatus which concerns on Embodiment 1 of this invention. It is a top view which shows the main part of the paper ejecting apparatus which concerns on Embodiment 1 of this invention. It is a front view which shows the main part of the paper ejecting apparatus which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the operation of the conventional sheet transfer apparatus. It is sectional drawing which shows the main part of the paper ejecting apparatus which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the operation of the paper ejecting apparatus which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the operation of the paper ejecting apparatus which concerns on Embodiment 1 of this invention. It is a perspective explanatory drawing which shows the operation of the paper ejecting apparatus which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows the operation of the paper ejecting apparatus which concerns on Embodiment 1 of this invention. It is a block diagram which shows the support member of the sheet transfer apparatus which concerns on Embodiment 2 of this invention. It is a plane block diagram which shows the modification of the support film.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[Embodiment 1]
FIG. 1 is a configuration diagram showing an overall outline of an image forming apparatus to which the sheet conveying apparatus according to the first embodiment of the present invention is applied.

<Overall configuration of image forming apparatus>
The image forming apparatus 1 according to the first embodiment is configured as, for example, a color copier. The image forming apparatus 1 is arranged inside an automatic document conveying device 3 that conveys a document (not shown) to a reading position of the image reading device 2, an image reading device 2 that reads an image of a document (not shown), and an image body 1a. It includes an image forming unit 4 as an example of an image forming means for forming an image on a recording paper 5 as an example of a sheet (recording medium) based on image data or the like read by the reading device 2. The apparatus main body 1a of the image forming apparatus 1 is formed of a support structural member, an exterior cover, and the like. Further, the broken line in the figure indicates a main transport path in which the recording paper 5 is transported inside the apparatus main body 1a of the image forming apparatus 1.

The image forming unit 4 of the image forming apparatus 1 holds a plurality of image forming apparatus 10 for forming a toner image developed by toner constituting a developer and a toner image formed by each image forming apparatus 10. Feeding that accommodates and supplies the intermediate transfer device 20 that is finally conveyed to the secondary transfer section that is secondarily transferred to the recording paper 5 and the required recording paper 5 that should be supplied to the secondary transfer section of the intermediate transfer device 20. The device 50 and a fixing device 40 for fixing the toner image on the recording paper 5 secondarily transferred by the intermediate transfer device 20 are provided.

The image-forming device 10 is a four-color image-forming device 10Y, 10M, 10C, 10K that exclusively forms toner images of four colors of yellow (Y), magenta (M), cyan (C), and black (K), respectively. It is configured. These four image forming devices 10 (Y, M, C, K) are arranged so as to be arranged in a row along the horizontal direction in the internal space of the device main body 1a.

Each image forming apparatus 10 (Y, M, C, K) includes a rotating photoconductor drum 11 as an example of an image holder. Each device as an example of the following toner image forming means is mainly arranged around the photoconductor drum 11. The main devices are a charging device 12 that charges the peripheral surface (image holding surface) capable of forming an image of the photoconductor drum 11 to a required potential, and image information (image information (image information) on the charged peripheral surface of the photoconductor drum 11. An exposure device 13 that irradiates light based on the signal) to form an electrostatic latent image for each color having a potential difference, and a toner of a developer of the corresponding color (Y, M, C, K) for the electrostatic latent image. A developing device 14 as an example of a developing means for developing into a toner image, a primary transfer device 15 as an example of a primary transfer means for transferring each toner image to an intermediate transfer device 20, and a photoconductor after the primary transfer. A drum cleaning device 16 or the like for cleaning by removing deposits such as toner remaining on the image holding surface of the drum 11. The reference numerals indicating the members of each image forming device 10 (Y, M, C, K) are attached only to the yellow image forming device 10Y and are attached to the other magenta (M), cyan (C) and black (K). It is omitted in the image forming apparatus 10 (M, C, K) of.

The photoconductor drum 11 has an image-holding surface having a photoconductive layer (photosensitive layer) made of a photosensitive material formed on the peripheral surface of a cylindrical or columnar base material to be grounded. The photoconductor drum 11 is supported so that power is transmitted from a drive device (not shown) and the photoconductor drum 11 rotates in the direction indicated by the arrow A.

The charging device 12 is composed of a contact-type charging roll that is arranged in contact with the photoconductor drum 11. A charging voltage is supplied to the charging device 12. As the charging voltage, when the developing device 14 performs reverse development, a voltage or current having the same polarity as the charging polarity of the toner supplied from the developing device 14 is supplied. As the charging device 12, a non-contact type charging device such as a scorotron arranged on the surface of the photoconductor drum 11 in a non-contact state may be adopted.

The exposure device 13 irradiates the photoconductor drum 11 with light according to image information by means of a plurality of LEDs (Light Emitting Diodes) as light emitting elements arranged along the axial direction of the photoconductor drum 11 of each image forming device 10. It consists of an LED print head that forms an electrostatic latent image. When the latent image is formed, the exposure device 13 receives image information of a document (not shown) read by the image reading device 2 from the control device 100 and image information corresponding to full color or black and white input to the image forming device 1 by any means. (Signal) is transmitted. The exposure apparatus 13 irradiates the peripheral surface of the photoconductor drum 11 after being charged with a laser beam configured according to the image information and the like input to the image forming apparatus 1, and an electrostatic latent image. You may use the thing which forms.

Each of the developing devices 14 is an example of a developing agent holder that holds the developing agent inside the apparatus housing 140 in which the opening and the developing agent accommodating chamber are formed and conveys the developing agent to the developing region facing the photoconductor drum 11. A screw auger that conveys the developer while stirring between the developing roll 141 and the supply and conveying member 142 such as the screw auger that supplies the developing agent to the developing roll 141 while stirring the developer. And the like, and a layer thickness regulating member (not shown) that regulates the amount (layer thickness) of the developing agent held on the developing roll 141 are arranged and configured. As each of the four color developers (Y, M, C, K), for example, a two-component developer containing a non-magnetic toner and a magnetic carrier is used.

The primary transfer device 15 is a contact-type transfer device provided with a primary transfer roll that contacts and rotates around the photoconductor drum 11 via an intermediate transfer belt 21 and supplies a primary transfer voltage. As the primary transfer voltage, a DC voltage indicating a polarity opposite to the charging polarity of the toner is supplied from a power supply device (not shown).

The drum cleaning device 16 is arranged so as to come into contact with the container-shaped main body, which is partially opened, and the peripheral surface of the photoconductor drum 11 after the primary transfer at a required pressure, and removes deposits such as residual toner for cleaning. It is composed of a cleaning plate to be cleaned and a sending member such as a screw auger that collects deposits such as toner removed by the cleaning plate and transports them to a collection system (not shown).

As shown in FIG. 1, the intermediate transfer device 20 is arranged so as to exist at a position below each image drawing device 10 (Y, M, C, K). The intermediate transfer device 20 is an example of an intermediate transfer body (image holding means) that rotates in the direction indicated by the arrow B while passing through the primary transfer section between the photoconductor drum 11 and the primary transfer device 15 (primary transfer roll). The intermediate transfer belt 21 of the above, a plurality of belt support rolls 22 to 27 that hold the intermediate transfer belt 21 in a desired state from the inner surface thereof and rotatably support the intermediate transfer belt 21, and the intermediate transfer belt 21 supported by the belt support roll 26. The secondary transfer device 30 and the secondary transfer device 30 as an example of the secondary transfer means for secondary transfer of the toner image on the intermediate transfer belt 21 to the recording paper 5 arranged on the outer peripheral surface (image holding surface) side of the above. The belt cleaning device 28 is mainly composed of a belt cleaning device 28 that removes and cleans deposits such as toner and paper dust that remain and adhere to the outer peripheral surface of the intermediate transfer belt 21 after passing through the belt.

As the intermediate transfer belt 21, for example, an endless belt made of a material in which a resistance modifier such as carbon black is dispersed in a synthetic resin such as a polyimide resin or a polyamide resin is used. Further, the belt support roll 22 is configured as a drive roll that is rotationally driven by a drive device (not shown), and the belt support rolls 23 and 24 are configured as surface rolls that form an image forming surface of the intermediate transfer belt 21. Reference numeral 25 denotes a tension applying roll that applies tension to the intermediate transfer belt 21 and a meandering correction roll that corrects the meandering of the intermediate transfer belt 21, and the belt support roll 26 is configured as a back support roll for secondary transfer. Reference numeral 27 denotes an opposed roll of the belt cleaning device 28.

The secondary transfer device 30 rotates in contact with the peripheral surface of the intermediate transfer belt 21 at the secondary transfer portion which is the outer peripheral surface portion of the intermediate transfer belt 21 supported by the belt support roll 26 in the intermediate transfer device 20. The secondary transfer roll 31, the driven roll 32, and the secondary transfer belt 33 bridged between the secondary transfer roll 31 and the driven roll 32, which constitute the secondary transfer means to which the secondary transfer voltage is supplied. It is a contact type transfer device equipped with. The secondary transfer roll 31 is arranged so as to come into contact with the belt support roll 26 whose position is fixed via the intermediate transfer belt 21 with a required pressing force. The secondary transfer device 30 includes a secondary transfer roll 31, a driven roll 32, a secondary transfer belt 33, and a belt support roll 26 that supports the back surface of the intermediate transfer belt 21. Further, a DC voltage showing the opposite polarity or the same polarity as the charging polarity of the toner is supplied to the secondary transfer roll 31 or the belt support roll 26 as the secondary transfer voltage.

The belt cleaning device 28 is configured in the same manner as the drum cleaning device 16 and is arranged so as to contact the partially open container-shaped main body and the peripheral surface of the intermediate transfer belt 21 after the secondary transfer with a required pressure. Consists of a cleaning plate (not shown) that removes and cleans residual toner and other deposits, and a sending member such as a screw auger (not shown) that collects and transports the toner and other deposits removed by the cleaning plate to the recovery system. Has been done.

The fixing device 40 is predetermined with a roll-shaped or belt-shaped heating rotating body 41 heated by a heating means so that the surface temperature is maintained at a required temperature, and a state substantially along the axial direction of the heating rotating body 41. It is configured by arranging a rotating body 42 for pressurization in the form of a roll or a belt that rotates in contact with the pressure of the above. In the fixing device 40, the contact portion where the heating rotating body 41 and the pressurizing rotating body 42 come into contact is a fixing processing unit that performs the required fixing treatment (heating and pressurization).

The paper feed device 50 includes a paper feed tray 51 as an example of a plurality of (or a single) paper storage container that stores the recording paper 5 of a desired size, type, etc. in a loaded state, and the paper feed tray 51 to the recording paper 5 It is mainly composed of a sending device 52 that sends out one by one. The paper feed tray 51 is attached so that it can be pulled out to the front side (side surface facing the user during operation) of the device main body 1a of the image forming apparatus 1, for example.

Examples of the recording paper 5 include plain paper used in electrophotographic copiers, printers and the like, thin paper such as tracing paper, and OHP sheets. In order to further improve the smoothness of the image surface after fixing, it is preferable that the surface of the recording paper 5 is as smooth as possible. For example, coated paper in which the surface of plain paper is coated with resin or the like, art paper for printing, or the like. So-called thick paper having a relatively large basis weight can also be preferably used.

Inside the apparatus main body 1a of the image forming apparatus 1, a plurality (or a single number) of recording papers 5 fed from the paper feed device 50 are conveyed to the secondary transfer unit between the paper feed device 50 and the secondary transfer device 30. ) Is provided with a paper feed transport path 55 composed of a pair of paper transport rolls 53 and 54, a transport guide (not shown), and the like. The paper transport roll pair 54 is configured as, for example, a roll (resist roll) for adjusting the transport timing of the recording paper 5 to the secondary transfer unit. Further, between the secondary transfer device 30 and the fixing device 40, a transport belt for transporting the recording paper 5 after the secondary transfer sent from the secondary transfer roll 31 of the secondary transfer device 30 to the fixing device 40. 56 is provided.

Further, on the downstream side of the fixing device 40 along the transport direction of the recording paper 5 and close to the discharge port of the recording paper 5, the fixed recording paper 5 sent out from the fixing device 40 is placed on the side surface of the device main body 1a. A paper ejection device 60 is arranged as an example of a sheet transporting apparatus for ejecting to an ejection paper accommodating portion (not shown) provided in. The paper ejection device 60 has a first transport path having a paper ejection roll pair 61 as an example of a conveying means for ejecting the fixed recording paper 5 to an ejection paper accommodating portion (not shown) provided on the side surface of the apparatus main body 1a. As an example, the discharge path 62, the introduction path 63 in which the transport direction of the recording paper 5 after fixing is switched downward along the vertical direction and introduced, and the front and back sides of the recording paper 5 introduced through the introduction path 63 are reversed. A paper reversing path 65 having a paper reversing roll pair 64 and a reversing discharge path 66 as an example of a second transport path for discharging the recording paper 5 whose front and back sides are reversed in the paper reversing path 65 are provided. The recording paper 5 whose front and back sides have been reversed by the paper reversing path 65 of the paper ejection device 60 is placed in an ejection paper accommodating portion (not shown) via the reversing ejection path 66 with the image side on which the toner image is fixed by the fixing device 40 facing down. It is discharged. The paper ejection device 60 will be described in detail later.

Further, when forming a double-sided image, the recording paper 5 whose front and back sides are reversed by the paper reversing path 65 of the paper ejection device 60 is fed through a double-sided transport path 67 provided with a plurality of paper ejection roll pairs 67a. It is conveyed again to 55, and images are formed on both sides of the recording paper 5.

In FIG. 1, a plurality of reference numerals 145 (Y, M, C, K) are arranged along a direction orthogonal to the paper surface, and include at least toner to be supplied to the corresponding developing apparatus 14 (Y, M, C, K). A toner cartridge containing a developer corresponding to each of the colors yellow (Y), magenta (M), cyan (C), and black (K) is shown. The black (K) toner cartridge 145K consumes more toner than the other yellow (Y), magenta (M), and cyan (C) toner cartridges 145 (Y, M, C). There are two.

Further, reference numeral 100 in FIG. 1 comprehensively controls the operation of the image forming apparatus 1 arranged on the back side of the image forming apparatus 10 (Y, M) of the yellow (Y) and magenta (M) of the apparatus main body 1a. The control device to be used is shown. The control device 100 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory) (not shown), a bus for connecting the CPU, the ROM, and the like, a communication interface, and the like. The control device 100 performs necessary image processing on the image signal input from the outside, and then exposes the exposure device 13 for each of the yellow (Y), magenta (M), cyan (C), and black (K) image forming devices. The image signal corresponding to (Y, M, C, K) is output.

Further, reference numeral 101 in FIG. 1 indicates a manual paper feeding device provided on the side surface of the device main body 1a so as to be openable and closable.

<Operation of image forming device>
Hereinafter, the basic image forming operation by the image forming apparatus 1 will be described.

Here, an operation of forming a full-color image composed by combining toner images of four colors (Y, M, C, K) using the four image-forming devices 10 (Y, M, C, K). Will be described.

When the control device 100 receives the command information of the request for the image forming operation (printing) on which the recording paper 5 is specified, the image forming apparatus 1 has four image forming apparatus 10 (Y, M, C, K) and an intermediate transfer apparatus. 20, the secondary transfer device 30, the fixing device 40, and the like are started.

Then, in each image forming apparatus 10 (Y, M, C, K), each photoconductor drum 11 first rotates in the direction indicated by the arrow A, and each charging device 12 has a required polarity on the surface of each photoconductor drum 11. (Negative property in the first embodiment) and the potential are charged respectively. Subsequently, the exposure apparatus 13 (Y, M, C, K) transmits an image signal input to the image forming apparatus 1 to the surface of the photoconductor drum 11 after charging for each color component (Y, M, C, K). ) Is irradiated with light based on the signal of the image obtained by converting to), and an electrostatic latent image of each color component composed of a required potential difference is formed on the surface thereof.

Subsequently, each image forming apparatus 10 (Y, M, C, K) corresponds to the electrostatic latent image of each color component formed on the photoconductor drum 11 with a required polarity (negativeness). Toners of colors (Y, M, C, K) are supplied from the developing rolls 141 and electrostatically adhered to perform development. The electrostatic latent image of each color component formed on each photoconductor drum 11 by this development is visualized as a toner image of four colors (Y, M, C, K) developed with the toner of the corresponding color. To be made.

Subsequently, when the toner image of each color formed on the photoconductor drum 11 of each image forming apparatus 10 (Y, M, C, K) is conveyed to the primary transfer unit, the primary transfer apparatus 15 moves the toner image of each color. The toner image is primarily transferred in a state of being sequentially superimposed on the intermediate transfer belt 21 rotating in the direction indicated by the arrow B of the intermediate transfer device 20.

Further, in each image forming apparatus 10 in which the primary transfer is completed, the drum cleaning apparatus 16 removes the deposits so as to scrape off the deposits to clean the surface of the photoconductor drum 11. As a result, each image forming device 10 is put into a state where the next image forming operation can be performed.

Subsequently, the intermediate transfer device 20 holds the toner image that has been primarily transferred by the rotation of the intermediate transfer belt 21 and conveys it to the secondary transfer unit. On the other hand, the paper feed device 50 feeds the required recording paper 5 such as plain paper or thick paper designated according to the image drawing operation to the paper feed transfer path 55. In the paper feed transport path 55, the paper transport roll pair 54 as a resist roll feeds and supplies the recording paper 5 to the secondary transfer unit in accordance with the transfer timing.

In the secondary transfer unit, the secondary transfer roll 31 of the secondary transfer device 30 collectively transfers the toner image on the intermediate transfer belt 21 to the recording paper 5. Further, in the intermediate transfer device 20 in which the secondary transfer is completed, the belt cleaning device 28 removes and cleans the deposits such as toner remaining on the surface of the intermediate transfer belt 21 after the secondary transfer.

Subsequently, the recording paper 5 on which the toner image is secondarily transferred is separated from the intermediate transfer belt 21 and the secondary transfer roll 31 and then conveyed to the fixing device 40 via the transfer belt 56. In the fixing device 40, the necessary fixing treatment (heating and addition) is performed by introducing the recording paper 5 after the secondary transfer into the contact portion between the rotating rotating body 41 for heating and the rotating body 42 for pressurization and passing the recording paper 5 through the contact portion. Pressure) is applied to fix the unfixed toner image on the recording paper 5. Finally, the recording paper 5 after the fixing is completed is shown on the side of the apparatus main body 1a by the paper ejection roll pair 61 when the image forming operation is only to form an image on one side of the recording paper 5. Do not discharge Paper is discharged to the storage section.

Further, when an image is formed on both sides of the recording paper 5, the recording paper 5 having an image formed on one side is not discharged to the discharge paper accommodating portion (not shown) by the paper discharge roll pair 61, and the transport direction of the recording paper 5 is formed. To switch down. The recording paper 5 conveyed downward is turned upside down by the paper inversion path 65 provided with the paper inversion roll pairs 64 via the introduction path 63, and then reaches the paper feed transfer path 55 via the double-sided transfer path 67. And be transported again. Then, the paper transport roll pair 54 feeds the recording paper 5 to the secondary transfer unit at the transfer timing, transfers the image to the back surface of the recording paper 5 and fixes it, and then uses the paper discharge roll pair 61 to perform the apparatus. It is discharged to a discharge paper accommodating portion (not shown) installed on the side of the main body 1a.

By the above operation, the recording paper 5 on which the full-color image formed by combining the toner images of four colors is formed is output.

<Structure of paper ejector>
FIG. 2 is a schematic configuration diagram showing a configuration of a paper ejection device 60 as an example of the sheet transport device according to the first embodiment.

As shown in FIG. 2, the paper ejection device 60 according to the first embodiment has an ejection path 62 for linearly transporting the recording paper 5 ejected from the fixing device 40 and a first ejection path 62 ejected from the fixing device 40. The introduction path 63 for transporting the recording paper 5 whose transport direction is switched downward along the vertical direction by the switching gate 68 of the above, and the recording paper 5 conveyed to the paper reversal path 65 are discharged by the second switching gate 69. It is provided with a curved inverted discharge path 66 that is conveyed so as to merge with the path 62.

The discharge path 62 includes an upper transport guide member 621 and 622 arranged above the discharge path 62, an upper end portion of the first switching gate 68 arranged below the discharge path 62, a lower transport guide member 623, and the like. It is composed of.

The reverse discharge path 66 is also used on the lower surface of the second switching gate 69 which also serves as the upper transport guide member arranged above the reverse discharge path 66 and the tip end portion 623a of the lower transport guide member 623 of the discharge path 62. From the upper transport guide member, the lower transport guide members 661 to 664 arranged below the inverted discharge path 66, and the transport roll pair 665 and the like arranged between the lower transport guide member 662 and the lower transport guide member 663. It is configured.

The introduction path 63 is provided on the lower end surface of the first switching gate 68 that also serves as the upper transfer guide member arranged above the introduction path 63, the upper transfer guide member 631 of the introduction path 63, and the upper part of the introduction path 63. Between the second switching gate 69 that also serves as the upper transport guide member to be arranged, the lower transport guide members 632 and 633 arranged below the introduction path 63, and the lower transport guide member 632 and the lower transport guide member 633. It is composed of a transfer roll pair 634 and the like to be arranged. The upper end portion 632a of the lower transport guide member 632 also constitutes a part (lower part) of the discharge path 62.

At the branch position where the lower end of the introduction path 63 and the double-sided transport path 67 branch, a film-like member provided in the double-sided transport path 67 so that the tip contacts the lower transport guide member 661 of the inverted discharge path 66. A branch member 671 made of the above is provided. The recording paper 5 transported to the paper reversing path 65 has a paper reversing roll pair 64 when the rear end along the transport direction is located between the branch member 671 and the second switching gate 69 at the time of reversing discharge. It is stopped and the direction of rotation is reversed. Then, the recording paper 5 conveyed to the paper reversal path 65 is conveyed to the reversal discharge path 66 by the paper reversal roll pair 64 whose rotation direction is reversed and the second switching gate 69 that switches the transfer path.

On the other hand, the recording paper 5 transported to the paper reversing path 65 has a paper reversing roll pair when the rear end along the transport direction is located between the paper reversing roll pair 64 and the branch member 671 when forming a double-sided image. 64 is stopped and the direction of rotation is reversed. Then, the recording paper 5 transported to the paper reversing path 65 is transported to the double-sided transport path 67 by the paper reversing roll pair 64 whose rotation direction is reversed and the branch member 671.

As shown in FIGS. 3 and 4A, the downstream side of the recording paper 5 at the confluence position 70 where the discharge path 62 and the reverse discharge path 66 meet is the transport direction of the recording paper 5. A paper ejection roll pair 61 is provided as an example of a conveying means in which the recording paper 5 is deformed into a wave shape and conveyed by a plurality of roll pairs having different outer diameters along the intersecting directions. The paper ejection roll pair 61 functions as a corrugation roll that deforms the recording paper 5 into a wavy shape.

The paper discharge roll pair 61 includes a first discharge roll member 614 in which a plurality of discharge rolls 611 and 612 formed of synthetic resins having different outer diameters along the axial direction of the rotation shaft 613 are alternately arranged, and a rotation shaft. It is composed of a second discharge roll member 615 in which a plurality of discharge rolls 617 formed of rubber or the like having the same outer diameter are arranged along the axial direction of the 616. The length of the first discharge roll member 614 along the axial direction is set longer in the discharge roll 611 having a relatively small outer diameter than in the discharge roll 612 having a relatively large outer diameter. The discharge roll 617 of the second discharge roll member 615 comes into contact with the discharge roll 611 having a relatively small outer diameter among a plurality of discharge rolls 611 and 612 having different outer diameters of the first discharge roll member 614. It is arranged like. A plurality of transport guide members 618 are arranged at positions facing the discharge roll 612, which has a relatively large outer diameter of the first discharge roll member 614.

The paper discharge roll pair 61 is, for example, rotationally driven by a drive source (not shown) in which the second discharge roll member 615 is not shown. The first discharge roll member 614 is driven to rotate by coming into contact with the discharge roll 617 of the second discharge roll member 615.

As shown in FIG. 4B, the recording paper 5 conveyed by the paper ejection roll pair 61 is a first ejection roll in which a plurality of rolls 611 and 612 having different outer diameters are alternately arranged along the axial direction. A state of being sandwiched between the member 614 and the second discharge roll member 615 and deformed into a wavy shape by a discharge roll 612 having a relatively large outer diameter and a discharge roll 611 adjacent along the axial direction and having a relatively small outer diameter. Is transported by. Therefore, as shown in FIG. 2, the recording paper 5 transported in a wavy shape is discharged so as to have increased rigidity and travel straight along the transport direction. As a result, the recording paper 5 discharged to the discharge paper storage unit (not shown) by the paper discharge roll pair 61 comes into contact with the recording paper 5 already discharged to the discharge paper storage unit (not shown) during the discharge, and the recording paper 5 It is stored on the recording paper 5 that has already been discharged to the discharge paper storage unit after being conveyed along the longitudinal direction of the discharge paper storage unit without disturbing the posture of the paper.

By the way, in the paper ejecting device 60 configured as described above, as shown in FIG. 4B, the recording paper 5 conveyed by the paper ejecting roll pair 61 functioning as the corrugation roll as described above is deformed into a wavy shape. Will be done. Therefore, the recording paper 5 nipped and conveyed by the paper ejection roll pair 61 is in a state of being deformed into a wavy shape along the rear end portion along the conveying direction.

In the paper ejection device 60, as shown in FIG. 5, when the front and back sides of the recording paper 5 are inverted and ejected, the recording paper 5 conveyed along the curved inverted ejection path 66 is along the conveying direction. It is deformed into a wave shape up to the rear end to increase rigidity. Therefore, the rear end 5a of the recording paper 5 transported along the curved reverse discharge path 66 forms the discharge path 62 due to the rigidity of the recording paper 5 when leaving the reverse discharge path 66 at the confluence position 70. It bounces off the lower surface of the member 622 and hits it, and a collision sound is generated. This collision sound is a sound of the rear end 5a of the recording paper 5 having increased rigidity hitting the upper transport guide member 622, which is jarring in a quiet office or the like.

Therefore, as shown in FIG. 6, the paper ejection device 60 according to the first embodiment is arranged from the inverted ejection path 66 toward the ejection path 62 at the confluence position 70, and is conveyed along the inverted ejection path 66. A comb-shaped supporting means 80 for supporting the corrugated convex portion 5b protruding toward the discharge path 62 side of the recording paper 5 is provided. Here, the comb-tooth shape means that the state in which the support means 80 is provided is a comb-tooth shape, and does not mean that the shape of the support means 80 itself is a comb-tooth shape. .. The support means 80 is configured by, for example, arranging a plurality of support means formed in a rectangular shape in a comb-teeth shape. In FIG. 6, reference numeral 71 indicates a static elimination brush that removes electric charges from the recording paper 5.

That is, as shown in FIG. 6, the paper discharge device 60 is the lower surface of the tip end portion 623a of the lower transport guide member 623 forming the reverse discharge path 66 at the confluence position 70 where the discharge path 62 and the reverse discharge path 66 meet. As an example of a comb-shaped supporting means for supporting a corrugated convex portion 5b protruding toward the discharge path 62 side of the recording paper 5 arranged toward the discharge path 62 and conveyed along the reverse discharge path 66. A support film 80 is provided. As shown in FIG. 3, the support film 80 is arranged from a flexible film-like member such as a Mylar film having a required thickness at a position corresponding to the discharge roll 611 on the paper discharge roll pair 61, and the discharge is performed. It is formed in a flat rectangular shape having a width equivalent to the length along the axial direction of the roll 611.

As shown in FIG. 6, the support film 80 has a lower transport guide member 623 at a position corresponding to the discharge roll 611 having a relatively small outer diameter among the first discharge roll members 614 of the paper discharge roll pair 61. It is provided on the lower surface of the tip portion 623a of the above by means such as adhesion or adhesion with double-sided tape or the like. Further, the support film 80 is arranged so that its tip 80a projects toward the discharge path 62 from the tangent line L drawn in parallel with the discharge path 62 at the nip portion of the paper discharge roll pair 61. Further, the support film 80 is arranged so as to have a tip 80a separated from the lower surface of the upper transport guide member 622 so as to form a gap.

<Action of paper ejector>
The paper ejection device 60 according to the first embodiment includes a paper guide member extending from a transport guide located at the center of the merging position toward a curved transport path in the merging position as follows. Compared to the case, at the merging position 70 where the curved reverse discharge path 66 merges with the linear discharge path 62, the rear end 5a of the recording paper 5 deformed into a wave shape carried through the reverse discharge path 66 suddenly hits. It is possible to reduce the impact noise caused by the rear end splash generated by being hit.

In the paper ejection device 60 according to the first embodiment, as shown in FIG. 2, when the recording paper 5 having an image fixed on one surface by the fixing device 40 is ejected to an ejection paper accommodating portion (not shown). In order to eject the recording paper 5 with the image side facing down to the discharge paper accommodating portion, the fixing device 40 switches the transport direction of the recording paper 5 having the image fixed on one side downward by the first switching gate 68. Then, the recording paper 5 whose transport direction is switched downward by the first switching gate 68 has the paper reversing roll pair while the rear end 5a along the transport direction is held by the paper reversing roll pair 64. The rotation direction of 64 is reversed, the transport path is switched by the second switching gate 69, and the paper is transported to the reverse discharge path 66.

The recording paper 5 whose transport path has been switched to the reverse discharge path 66 is discharged to a discharge paper accommodating portion (not shown) by the paper discharge roll pair 61 in a curved state following the shape of the reverse discharge path 66. At this time, as shown in FIG. 4B, the recording paper 5 is deformed into a wave shape by the first discharge roll member 614 provided with a plurality of discharge rolls 611 and 612 having different outer diameters along the axial direction. Will be done.

As shown in FIG. 7, the corrugated recording paper 5 protrudes toward the discharge path 62 of the recording paper 5 when the rear end 5a moves from the reverse discharge path 66 to the discharge path 62. The corrugated convex portion 5b is supported by a plurality of support films 80 provided in a comb-teeth shape.

More specifically, the recording paper 5 deformed into a wavy shape is deformed into a curved shape following the shape of the reverse discharge path 66 when being conveyed along the reverse discharge path 66. Then, the rear end 5a of the recording paper 5 deformed into a wavy shape is deformed from a curved shape to a flat shape when shifting from the inverted discharge path 66 to the discharge path 62.

By the way, as shown in FIGS. 8 to 10, the inverted discharge path 66 is provided with a comb-shaped support film 80 from the inverted discharge path 66 toward the discharge path 62. Of the rear end 5a of the recording paper 5 deformed into a wave shape, the wave-shaped convex portion 5b protruding toward the discharge path 62 is discharged from the inverted discharge path 66 in a state of being in contact with the comb-shaped support film 80. It is supported and guided to 62. As a result, the rear end 5a of the recording paper 5 deformed into a wavy shape tries to elastically deform from the curved shape to the flat shape when shifting from the curved inverted discharge path 66 to the linear discharge path 62. , The corrugated convex portion 5b is supported in contact with the comb-shaped support film 80. Therefore, the rear end 5a of the recording paper 5 deformed into a wavy shape is gradually supported by the plurality of support films 80 without colliding with the lower surface of the upper transport guide member 622 forming the discharge path 62. In the state of returning to the linear shape which is the shape of the discharge path 62, the process shifts to the discharge path 62. After that, the rear end 5a of the recording paper 5 deformed into a wavy shape is discharged to a discharge paper accommodating portion (not shown) by the paper discharge roll pair 61.

Further, since the support film 80 is formed of a film-like member that is arranged in a comb-teeth shape and has flexibility, and a gap is formed between the support film 80 and the discharge path 62, the support film 80 is conveyed through the discharge path 62. It is prevented or suppressed that it becomes a transport resistance of the recording paper 5.

Further, the recording paper 5 discharged with the image surface facing up as usual is the recording paper 5 conveyed in the discharge path 62 because the corrugated convex portion 5b passes above the comb-shaped support film 80. It is prevented or suppressed that it becomes a transport resistance.

As described above, in the paper discharge device 60 according to the first embodiment, the curved reverse discharge path 66 is deformed into a wave shape to be conveyed at the confluence position 70 where the curved reverse discharge path 66 merges with the linear discharge path 62. It is possible to reduce or prevent the sound generated when the rear end 5a of the recording paper 5 hits the discharge path 62.

On the other hand, when a paper guide member extending from the transport guide located at the center of the merging position toward the curved transport path in the merging position is simply provided, the paper guide member discharges the recording paper 5. Since it deviates from the wave-shaped convex portion protruding toward the path side, it is unavoidable that the rear end 5a of the recording paper 5 deformed into the wave shape carried on the inverted discharge path 66 hits the discharge path 62, and the wave. It is not possible to reduce or prevent the noise generated when the rear end 5a of the recording paper 5 deformed into a shape hits the discharge path 62.

[Embodiment 2]
FIG. 11 is a configuration diagram showing a main part of a paper ejecting device 60 as an example of the sheet conveying device according to the second embodiment of the present invention.

In the paper ejection device 60 according to the second embodiment, as shown in FIG. 11, the support film 80 is formed in a tapered shape and a curved tip toward the downstream side along the conveying direction of the recording paper 5. There is.

Therefore, in the paper ejection device 60 according to the second embodiment, as shown in FIG. 11B, when the support film 80 is attached so as to be slightly inclined with respect to the lower surface of the tip portion 623a of the lower transport guide member 623. Even so, it is possible to prevent the contact resistance with the recording paper 5 from fluctuating at both left and right edges.

Of course, as the support film 80, as shown in FIG. 12, a film in which the base end portions of the plurality of support films 80 are integrally formed and literally formed in a comb-teeth shape may be used.

Since other configurations and operations are the same as those in the first embodiment, the description thereof will be omitted.

In the above embodiment, the case where the image forming apparatus is applied to a color copying machine adopting the electrophotographic direction has been described as an example of the image forming apparatus, but the present invention is not limited to this, and the image forming unit 4 is an electrophotographic method. The method is not limited to the above, and other methods such as an inkjet method, a thermal head method, and a lithograph method may be adopted as long as an image can be formed on a recording medium.

1 ... Image forming apparatus 1a ... Device main body 60 ... Paper ejection device 61 ... Paper ejection roll pair 62 ... Discharging path 66 ... Inverted ejection path 80 ... Support film

Claims (9)

Of the first and second transport paths for transporting the sheet, the curved second transport path merges with the linear first transport path to the downstream side along the sheet transport direction at the confluence position. A transporting means for transporting the sheet by deforming the sheet into a wavy shape by a plurality of roll pairs arranged and having different outer diameters along a direction intersecting the transport direction.
The wave that is arranged from the second transport path toward the first transport path at the confluence position and protrudes toward the first transport path side of the sheet that is transported along the second transport path. A comb-shaped support means that supports the convex part of the shape,
A sheet transfer device comprising. The sheet transport according to claim 1, wherein the transport means alternately arranges a first roll having a relatively large outer diameter and a second roll having a relatively small outer diameter along the axial direction. Device. The sheet transport device according to claim 2, wherein the support means is arranged at a position corresponding to the second roll. The second aspect of claim 2, wherein the support means is arranged so that its tip protrudes toward the first transport path side from a tangent line provided at the nip portion of the second roll in parallel with the first transport path. Sheet transfer device. The sheet transport device according to claim 1, wherein the plurality of transport paths include a first transport path for transporting the sheet in a straight line and a second transport path for transporting the sheet in a curved state. The sheet transport device according to claim 5, wherein the support means is arranged in the second transport path. The sheet transport device according to claim 1, wherein the support means is made of a flexible film-like member. The sheet transport device according to claim 7, wherein the support means is formed in a tapered shape and a curved tip toward the downstream side along the transport direction of the sheet. An image forming means for forming an image on a sheet and
A sheet transporting means for transporting the sheet and
With
An image forming apparatus using the sheet conveying device according to any one of claims 1 to 8 as the sheet conveying means.

Images