JP2006151605A - Sheet conveying device, sheet conveying method, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce collision noise of a sheet in a confluence of sheet conveying passages without providing a guide member in the confluence. <P>SOLUTION: A sheet conveying device 125 is provided with a before-resist conveying path 103, a double-face path 121, which the before-resist conveying path 102, a pair of paper feeding rollers 106 arranged at the upstream vicinity of the confluence point path with the double-face path near the confluence, and a control means for controlling the pair of paper feeding rollers 106 so that an upstream end part of a sheet, which is conveyed by the double-face path, is overlapped with a downstream end of a sheet, which is conveyed by the before-resist conveying path, in the confluence. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sheet conveying apparatus having a merging point in a sheet conveying path, a sheet conveying method for conveying a sheet by the sheet conveying apparatus, and an image forming apparatus that includes the sheet conveying apparatus and forms an image on a sheet.

  2. Description of the Related Art Conventionally, image forming apparatuses such as copiers, facsimiles, printers, and multi-function machines thereof, or sheet processing apparatuses that process sheets on which images are formed by the image forming apparatus include a sheet conveying apparatus that conveys the sheet. ing.

  Some sheet conveying apparatuses are configured to merge a plurality of sheet conveying paths for guiding a sheet and convey them by one sheet conveying path (see Patent Document 1). FIG. 5 shows a joining portion of the sheet conveyance path in the sheet conveying apparatus.

  In the sheet conveying apparatus 201 illustrated in FIG. 5, the rear end portion (upstream end portion) of the sheet passing through the curved conveyance path 223 is curved and passes through the junction 225 between the curved conveyance path 223 and the straight conveyance path 224. Therefore, it passes through the step of the junction 225. At this time, since the rear end portion of the sheet is in contact with the downstream side wall 225a of the merging portion 225, an annoying impact sound may occur. In particular, the impact sound was loud when the sheet was stiff or when the sheet conveyance speed was fast.

  On the other hand, in general, the image forming apparatus and the sheet processing apparatus are preferred to have less noise. For this reason, the sheet conveying apparatus 201 shown in FIG. 5 is provided with a guide member 226 that can be tilted with the joining point 231 of the joining portion 225 as the base end side so that no impact sound is generated. The guide member 226 supports the trailing end of the sheet passing through the curved conveyance path 223 and is pushed downstream by the sheet passing through the linear conveyance path 224 to pass through the linear conveyance path 224. So as not to obstruct the passage of the seat to be performed.

Japanese Utility Model Publication No. 6-3951

  However, in the conventional sheet conveying apparatus 201, since the sheet passing through the merging portion passes while rubbing the guide member, the guide member may be peeled off due to long-term use, and it is necessary to increase the number of times of maintenance. . For this reason, the advent of a sheet conveying apparatus with a low impact sound has been awaited without using a guide member.

  In addition, the image forming apparatus provided with the conventional sheet conveying apparatus has a low number of maintenance operations, and thus the image forming efficiency is poor.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet conveying apparatus that reduces the impact noise of a sheet at a merging portion without providing a guide member at the merging portion of a sheet conveying path.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet conveying method that can reduce the impact noise of a sheet at a merging portion without using a guide member at the merging portion of a sheet conveying path.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that includes a sheet conveying device with a reduced impact sound without providing a guide member at a merging portion of a sheet conveying path and reduces the number of maintenance operations.

  In order to achieve the above object, a sheet conveying apparatus according to the present invention includes a first sheet conveying path, a second sheet conveying path that merges with the first sheet conveying path, and the first sheet conveying path. The sheet conveying means disposed in the vicinity of the upstream of the merging point with the second sheet conveying path, and the upstream end portion of the sheet conveyed by the second sheet conveying path at the merging point pass through the merging point. And control means for controlling the sheet conveying means so as to overlap the downstream end portion of the sheet conveyed by the first sheet conveying path.

  In order to achieve the above object, in the sheet conveying method of the present invention, the sheet is fed by the second conveying path toward the merging point where the first sheet conveying path is merged, and the merging point in the first sheet conveying path is determined. Sheets are fed toward the merging point by the first sheet conveying path by conveying means arranged in the vicinity of the upstream, and an upstream end portion of the sheet conveyed by the second sheet conveying path passes through the merging point. In some cases, the downstream end portion of the sheet conveyed by the first sheet conveyance path is overlapped.

  In order to achieve the above object, an image forming apparatus of the present invention includes an image forming unit that forms an image on a sheet, and the sheet conveying apparatus that conveys the sheet.

  In the sheet conveying apparatus of the present invention, the upstream end of the second sheet is received by the downstream end of the first sheet until the upstream end of the second sheet passes the junction. Even without providing a guide member that is conventionally required, the upstream end of the second sheet can be prevented from colliding with the inner wall of the first sheet conveyance path at the merging point. Sound can be reduced. Further, since the guide member is not provided, it is not necessary to perform maintenance accordingly.

  Since the image forming apparatus of the present invention includes the sheet conveying device with a low impact sound, the operation sound can be reduced. Further, since the sheet conveying apparatus with a reduced number of maintenance is provided, the image forming efficiency can be increased.

  Hereinafter, a sheet conveying apparatus according to an embodiment of the present invention and an image forming apparatus including the sheet conveying apparatus will be described with reference to the drawings.

  The sheet conveying apparatus of the present invention is not provided only in an image forming apparatus that forms an image on a sheet. It is also provided in a sheet processing apparatus such as a sheet punching apparatus that punches holes in a sheet, a sheet binding apparatus that binds sheet bundles, and a sheet folding apparatus that folds sheet bundles. That is, the sheet conveying apparatus of the present invention is provided in a sheet handling apparatus that handles sheets, such as an image forming apparatus and a sheet processing apparatus.

(Image forming device)
FIG. 1 is a cross-sectional view of the image forming apparatus according to the present embodiment along the sheet conveying direction. This image forming apparatus is an electrophotographic copying machine which is an example of an electrophotographic image forming apparatus. In addition, the numerical value taken up by this embodiment is a reference numerical value shown in order to make this invention easy to understand, and does not limit this invention. The numerical value is an approximate numerical value.

  The electrophotographic copying machine 100 includes an image reading apparatus 103 that reads a document and a sheet supply device 101 that automatically feeds the document to the image reading apparatus 103 in the apparatus main body 100A. The image reading device 103 reads a document supplied by the sheet supply device 101 and a document (including a book, a magazine, etc.) placed on the document table glass 102 of the image reading device 103. Note that the sheet supply apparatus 101 is not necessarily provided.

  The image reading device 103 irradiates a document passing through the document table glass 102 by the sheet supply device 101 or a document placed on the document table glass 102, and the reflected light is electrically transmitted by a plurality of mirrors M and lenses Ln. It is designed to convert to a signal. The apparatus main body 100A forms an image of the irradiation light of the electric signal on the photosensitive drum 104 as an image forming unit.

On the other hand, a plurality of cassettes 105 are provided below the apparatus main body 100A. In FIG. 1, one cassette is shown, and the other cassettes are not shown. A recording material (hereinafter referred to as “sheet”) is stacked on the cassette. Among the plurality of cassettes 105, the cassette 105 to be used is selected based on information input by the user from an operation unit (not shown) of the copying machine 100, or an appropriate sheet is stacked based on the size of the document. The selected cassette 105 is selected. Examples of the sheet include thin paper having a basis weight of about 50 g / m ² to thick thick paper having a basis weight of about 250 g / m ² .

  The single sheet fed by the paper feeding / separating device 105A of the selected cassette is guided to the pre-registration conveyance path 108 by the paper feeding / conveying roller pair 106 and the pre-registration roller pair 107, and is upstream of the registration roller pair 110. After passing the pre-registration sensor 109 that detects the passage of the sheet disposed on the side, the sheet is conveyed to the registration roller pair 110.

  Thereafter, the registration roller pair 110 synchronizes the rotation of the photosensitive drum 104 and the scanning timing of the image reading device 103 under the ON signal of the pre-registration sensor 109 to transfer the sheet to the photosensitive drum 104 and transfer charging. It is conveyed between the charger 111 and the separation charger 112. The transfer charger 111 transfers the toner image formed on the photosensitive drum 104 to a sheet, and the separation charger 112 separates the sheet having the toner image transferred from the photosensitive drum 104. Thereafter, the pre-fixing conveyance unit 113 sends the sheet to the fixing device 114. The fixing device 114 heats and presses the sheet to fix the toner image on the sheet, and then sends the sheet to the inner paper discharge roller 123.

  In the case of single-sided copying, the inner discharge roller 123 sends the sheet from the fixing device 114 to the discharge reversing unit 115, and the outer discharge roller 116 discharges the sheet to the outside of the main body apparatus.

  In the case of duplex copying, the first flapper 118 of the paper discharge reversing unit 115 guides the sheet fed from the fixing device 114 to the refeed conveyance path 119. The second flapper 117 guides the sheet to the reverse roller 122, and the reverse roller 122 guides the sheet to the reverse path 120. The reverse roller 122 rotates in the reverse direction while the end of the sheet passing through the refeed conveyance path 119 is nipped, and feeds the sheet into the double-sided path 121 by the guidance of the second flapper 117. During this time, the sheet is switched back and turned upside down.

  Thereafter, the sheet conveyed through the double-sided path 121 is received while the double-sided conveying roller pair 124 has stopped rotating. The sheet is bent by being received by the duplex conveying roller pair 124 that has stopped rotating, and when the sheet is skewed, the sheet is straightened. Thereafter, as described above, the sheet is conveyed to the registration roller pair 110, the toner image is transferred by the photosensitive drum 104, and then discharged to the outside of the apparatus main body 100A through the fixing device 114.

  In the above configuration, each part of the copying machine 100 is controlled and operated by the CPU 140 as a control means. As shown in FIG. 4, sensors such as the pre-registration sensor 109 are connected to the CPU 140. Further, driving sources such as plungers PL1 and PL2 for tilting the first and second flappers 118 and 117, a motor M1 for the pair of paper feeding and conveying rollers 106, a motor M2 for the pair of pre-registration rollers 107, a motor M3 for the pair of double-sided conveying rollers, etc. Is also connected. The CPU 140 controls each unit according to an operation procedure stored in the ROM 140a.

(Sheet conveying device)
A sheet conveying device 125 according to the present embodiment is provided in the copying machine 100. As shown in FIGS. 1 and 2, the sheet conveying device 125 includes a pre-registration conveyance path 108 as a first sheet conveyance path for guiding the sheet P1 from the cassette 105, and a sheet P2 on which a toner image is formed on one side. The sheet P1 (hereinafter, sent out from the cassette 105) is fed to a double-sided path 121 as a second sheet-conveying path that joins the pre-registration conveyance path 108 and a junction 130 of the pre-registration conveyance path 108 and the double-sided path 121. By controlling the motor M1 and the pair of paper feeding and conveying rollers 106 and the motor M1 as the sheet conveying means for conveying the sheet as the first sheet P1, the sheet P2 (hereinafter, the sheet passing through the double-sided path 121 is a second one). Until the upstream end (rear end P2b) of the sheet P2 passes the junction X, the downstream end (leading end P1a) of the first sheet P1. In and a CPU140, etc. as control means for conveying the first sheet P1 to a position capable of receiving the rear end portion P2b of the second sheet P2.

  The arrangement of the rollers near the junction 130 and the guide members will be described with reference to FIGS. FIG. 2 is a cross-sectional view of the main part showing the guide member and roller arrangement in the vicinity of the merging portion.

  The pre-registration conveyance path 108 includes linear sheet passing walls 108a and 108b that are parallel to each other. The double-sided path 121 includes curved sheet passing walls 121a and 121b that are parallel to each other. The double-sided path 121 is curved in an arc shape with a radius of curvature of about 40 mm and merges with the pre-registration conveyance path 108. The double-sided path 121 is connected to the sheet passing wall 108a. The whole part that has joined is referred to as a joining part 130. The merging angle at which the double-sided path 121 merges with the pre-registration conveyance path 108 is an acute angle.

  In FIG. 2, when the intersection between the sheet passing wall 121b having a large radius of curvature of the double-sided path 121 and the sheet passing wall 108a on the double-sided path 121 side of the pre-registration transport path 108 is a junction point X, 106 is arranged upstream from the junction X by a distance L1 (15 mm).

  The pair of paper feed rollers 106 is disposed at a position where the distance S between the nip tangent line formed by the paper feed rollers 106 and the sheet passing wall 108b of the pre-registration transport path 108 is 4 mm. . As described above, when the downstream end portion (leading end portion P1a) of the first sheet P1 passes the merging point X, the direction in which the paper feeding / conveying roller 106 conveys the first sheet P1 is changed to the pre-registration at the merging point X. The leading edge P1a is set in a direction away from the sheet passing wall 108b as the inner wall of the conveyance path 108. For this reason, the first sheet P1 is conveyed away from the sheet passing wall 108b in the junction 130.

  Under the control of the CPU 140, the motor M3 is started at a predetermined timing after the driving of the registration roller pair 110 is turned on, and the double-sided conveyance roller pair 124 re-conveys the second sheet P2. The second sheet P <b> 2 is conveyed to the pre-registration conveyance path 108 via the merge unit 130 and is conveyed to the registration roller pair 110. Thereafter, in the same manner as when the toner image is formed on one side of the second sheet P2, a toner image is formed on the other side and is discharged to the outside of the apparatus main body 100A. Thus, a series of automatic duplex copying operations by the copying machine 100 is completed.

  Next, the conveying operation of the first and second sheets P1 and P2 of the sheet conveying device 125 in the merge unit 130 will be described with reference to FIGS. FIG. 3 is a diagram of a sheet conveyance diagram of the second sheet P2 to which the toner image is continuously transferred to the other surface and the first sheet P1 which has been fed from the cassette 105 and has not yet been transferred with the toner image. is there.

  In FIG. 3, the horizontal axis indicates time, the left vertical axis indicates the position of the sheet passing through the duplex path 121 and the pre-registration conveyance path 108, and the right vertical axis indicates the sheet passing through the pre-registration conveyance path 108. Indicates the position. Note that the sheet conveying operation of the sheet conveying apparatus 125 according to the present embodiment is exemplified by a sheet conveying operation when an A4 size sheet (297 mm × 210 mm) is laterally fed, that is, the sheet length in the sheet conveying direction is 210 mm. Will be explained.

  First, the first sheet copy is completed, and the second sheet P2 that has been conveyed on the duplex path 121 to copy the second sheet is fed to the front end P2f (FIG. 1) at the nip of the duplex conveyance roller pair 124 that has stopped rotating. If it is skewed, it will be corrected straight.

  Thereafter, the CPU 140 starts the motor M3 after a predetermined time T1 (300 ms) by a timer in the CPU 140, and rotates the duplex conveying roller pair 124. The second sheet P2 is re-conveyed by the double-sided conveyance roller pair 124 at a sheet conveyance speed of 200 mm / s. The CPU 140 stops the rotation of the pre-registration roller pair 107 after a time T2 (480 ms) after the leading end P2f of the second sheet P2 passes the junction point X and turns on the pre-registration sensor 109. At this time, a loop (deflection) for correcting the skew of the second sheet P2 is formed on the upstream side of the registration roller pair 110. The amount of the loop is 6 mm. Further, the rear end P2r of the second sheet is on the front side (upstream side) of 24 mm passing through the junction X.

  On the other hand, the first sheet P1 sent out from the cassette 105 is transported on the pre-registration transport path 108 at a sheet transport speed of 200 mm / s by the transport force of the pair of paper feed transport rollers 106 for the first side copy. . The CPU 140 stops the motor M1 after the time T3 (600 ms) after the sheet front end portion P2f of the second sheet P2, which is the preceding sheet, turns on the pre-registration sensor 109, and rotates the pair of paper feed conveyance rollers 106. Stop. At this time, the first sheet P1 stands by at a position where the sheet front end P1f protrudes from the junction X by L2 (10 mm).

  In this state, the CPU 140 rotates the registration roller pair 110 to convey the second surface of the second sheet P2 to the image forming unit after a time T4 (750 ms) after the pre-registration sensor 109 is turned on. However, the sheet rear end P2r of the second sheet P2, which is the preceding sheet, passes through the junction X after a time T5 (120 ms) after the registration roller pair 110 starts to rotate. The first sheet P1, which is the subsequent sheet, starts to rotate after the time T6 (350 ms) after the registration roller pair 110 starts to rotate, and the sheet feeding / conveying roller pair 106 begins to rotate. , And conveyed by the pre-registration roller pair 107.

  In the following description, the first sheet P1 may be referred to as a subsequent sheet P1, and the second sheet P2 may be referred to as a preceding sheet P2.

  That is, when the trailing edge P2r of the second sheet P2 that is the preceding sheet passes through the merging point X, the sheet leading edge P1f of the first sheet P1 that is the succeeding sheet is at a position 10 mm from the merging point X. The sheet rear end P2r of the second sheet P2 is between 10 mm before the merging point X (upstream side). Therefore, the sheet front end portion Pa of the first sheet P1 and the rear end portion P2b of the first sheet P2 overlap each other.

Here, as described above, the double-sided path 121 in the junction 130 is curved in an arc shape with a curvature radius of about 40 mm. For this reason, the second sheet P <b> 2 is curved and deformed by the curved shape of the double-sided path 121, and is conveyed by the double-sided path 121. Then, when the rear end P2r of the sheet passes the junction point X, the second sheet P2 is straightened by being released from the bending deformation. At this time, the rear end portion P2b of the sheet may hit the sheet passing wall 108b of the pre-registration conveyance path 108. This phenomenon is prominent when the sheet is thick paper having a basis weight of about 250 g / m ² . Further, when the conveyance speed of the second sheet is increased, there is a risk of hitting the sheet passing wall 108b of the pre-registration conveyance path 108 even if the sheet is weak.

  However, in the sheet conveying device 125 of the present embodiment, the sheet leading end P1f of the succeeding sheet P1 protrudes 10 mm downstream from the joining point X, and the succeeding sheet P1 waits. In addition, the pair of sheet feeding and conveying rollers 106 sandwich the sheet leading end portion P2a. Further, as described above, the distance S between the nip tangent of the pair of paper feeding and conveying rollers 106 and the sheet passing wall 108b of the pre-registration conveying path 108 is set to 4 mm, and the leading end P1a of the succeeding paper P1 is passed through the sheet. It is away from the paper wall 108b. For this reason, the leading edge P1a of the succeeding paper P1 receives the trailing edge P2b of the preceding paper P2 that is going to be straight, and prevents the trailing edge P2b of the preceding paper P2 from hitting the sheet passing wall 108b. That is, the leading end portion P1a of the first sheet P1, which is a subsequent sheet, serves the same function as a conventional guide member.

  As a result, at the moment when the sheet trailing edge P2r of the second sheet P2 that is the preceding sheet passes through the merging point X, the second sheet that is the preceding sheet is buffered by the sheet leading end portion P1a of the first sheet P1 that is the following sheet. The sheet rear end portion P2b of the sheet P2 is not hit against the sheet passing wall 108b. Therefore, sheet collision noise in the sheet conveying device 125 is greatly reduced.

  Thereafter, the sheet conveying device 150 conveys the second sheet P2 which is the preceding sheet, and after the time difference (230 ms) obtained by subtracting the time T5 from the time T6, conveys the first sheet P1 of the subsequent sheet, A sheet interval T7 (150 ms) necessary for sensing when the sheet passes through the sensor 109 is secured (equivalent to 30 mm), and the sheet is conveyed.

  Note that the sheet conveying device 125 of the present embodiment is configured to send the first sheet P1 after feeding the second sheet to the joining unit 130, but the first sheet P1 is fed at the leading end P1a of the first sheet P1. The second sheet P2 may be fed after the first sheet P1 has been fed in advance to a position where the rear end portion P2b of the second sheet P2 can be received, and the order of feeding the sheets is not limited. . That is, by the time the rear end portion P2b of the second sheet P2 passes through the joining point X, the front end portion P1a of the first sheet P1 is in a position where the rear end portion P2b of the second sheet P2 can be received. It only has to be.

  Further, the first sheet P1 waits and receives the second sheet P2, but depending on the transport timing of the first sheet P1, the first sheet P1 is transported without waiting. However, the rear end portion P2b of the second sheet P2 may be received. Note that the second sheet P2 can be reliably received by waiting the first sheet P1 and receiving the rear end portion P2b of the second sheet P2. Further, if the rear end portion P2b of the second sheet P2 is received while being conveyed without waiting for the first sheet P1, it is not necessary to stop the first sheet P1, and the sheet conveyance control of the CPU 140 is facilitated. .

  Moreover, although the 1st sheet | seat and the 2nd sheet | seat are sent alternately to a junction part, it is not necessary to send it alternately.

  Further, in the sheet conveying apparatus of the present embodiment, the distance L1 between the confluence X of the bending portion 130 and the pair of sheet feeding / conveying rollers 106 is 15 mm, but as long as the sheet feeding / conveying roller pair 106 can be arranged at about 10 mm. You may get closer. Further, the nip tangent formed by the pair of sheet feeding and conveying rollers 106 and the sheet passing wall 108b on the opposite side to the junction point X among the pair of sheet passing walls 108a and 108b that are linearly and parallelly opposed to each other. Although the interval S is set to 4 mm, the distance S may be increased within a range that does not adversely affect the conveyance of the sheet, and is not limited to the numerical values of the present embodiment as long as the subsequent sheet can exhibit the effect as a guide member. Absent.

  Further, in the present embodiment, the diagram in the vicinity of the merging portion is described with the sheet size being A4 and the conveyance speed being 200 mm / s. However, after the preceding sheet at the moment of passing through the curved portion at any sheet size and conveyance speed. It goes without saying that the same effect can be obtained if the end portion is received by the leading end portion of the succeeding paper that joins from the other path.

  As described above, the sheet conveying apparatus 150 according to the present embodiment has a plurality of sheet conveying paths, and is curved when one sheet conveying path is curved and merges with the other sheet conveying path. The trailing edge of the preceding paper at the moment of exiting the section is received by the leading edge of the succeeding paper that merges from the other sheet conveyance path, and the leading edge of the succeeding paper has the same function as a conventional guide member. Therefore, unlike the conventional case, the impact sound can be reduced with a simple structure without providing a guide member.

  Since the sheet conveying device 150 does not need to be provided with a conventional guide member (reference numeral 226 in FIG. 5), it is not necessary to push the guide member away from the succeeding sheet at the leading end of the succeeding sheet and pass the joining portion. Can be prevented, and the succeeding paper can be conveyed accurately.

  The sheet conveying device 150 has a structure that can reduce component cost, assembly cost, maintenance cost, and the like by not providing a guide member.

  The sheet conveying device 150 is configured to overlap the preceding sheet and the succeeding sheet. However, by adjusting the start timing of the succeeding sheet after the overlapping, it is easy to cope with the small sheet interval control, and higher productivity is required. A sufficient effect can be exhibited also for the image forming apparatus.

FIG. 3 is a cross-sectional view of the image forming apparatus according to the present embodiment along the sheet conveyance direction. It is a front view of the sheet conveying apparatus of the embodiment of the present invention. FIG. 6 is a diagram of a sheet conveyance diagram of a second sheet on which a toner image is fixed on one side and a toner image is transferred on the other side, and a first sheet on which no toner image is formed. FIG. 3 is a control block diagram of the image forming apparatus, and shows only a part related to the sheet conveying apparatus. It is a front view of the conventional sheet conveying apparatus.

Explanation of symbols

P1 first sheet (sheet conveyed through the first sheet conveyance path)
P1f The leading edge of the first sheet (the sheet conveyed through the first sheet conveying path) P1a The leading edge (the downstream edge) of the first sheet (the sheet conveyed through the first sheet conveying path)
P2 Second sheet (sheet conveyed through the second sheet conveyance path)
P2f The leading edge of the second sheet (the sheet conveyed through the second sheet conveyance path) P2r The trailing edge of the second sheet (the sheet conveyed through the second sheet conveyance path) P2b The second sheet (the second sheet) The rear end (upstream end) of the sheet conveyed through the second sheet conveyance path)
X Junction point 100 Electrophotographic copying machine (image forming device)
104 Photosensitive drum (image forming means)
106 Feeding roller pair (sheet conveying means)
107 Pre-registration roller pair 108 Pre-registration conveyance path (first sheet conveyance path)
108a Sheet passing wall 108b Sheet passing wall 109 Pre-registration sensor 110 Registration roller pair 121 Double-sided path (second sheet conveyance path)
121a Sheet passing wall 121b Sheet passing wall 124 Double-sided conveying roller pair 125 Sheet conveying device 130 Merge unit 140 CPU (control means)
M1 paper feed roller pair motor (sheet transport means)
M2 Motor for pair of rollers before registration M3 Motor for pair of double-sided conveyance rollers

Claims (5)

A first sheet conveyance path;
A second sheet conveyance path that merges with the first sheet conveyance path;
A sheet conveying means disposed in the vicinity of the upstream of the junction with the second sheet conveying path in the first sheet conveying path;
When the upstream end of the sheet conveyed by the second sheet conveyance path at the merging point passes through the merging point, the sheet overlaps with the downstream end of the sheet conveyed by the first sheet conveyance path. Control means for controlling the sheet conveying means,
A sheet conveying apparatus comprising:   The control means controls the sheet conveying means so that the upstream end portion of the sheet conveyed in the second sheet conveying path is conveyed in the first sheet conveying path before passing the merging point. 2. The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is kept waiting at a position where the downstream end portions of the sheets to be overlapped. The sheet is fed by the second conveyance path toward the merging point where it merges with the first sheet conveyance path,
A sheet is sent toward the merging point by the first sheet conveying path by conveying means disposed in the vicinity of the upstream of the merging point in the first sheet conveying path;
When the upstream end portion of the sheet conveyed by the second sheet conveyance path passes the merging point, the downstream end portion of the sheet conveyed by the first sheet conveyance path is overlapped. Sheet transport method.   Until the upstream end portion of the sheet conveyed in the second sheet conveyance path passes through the merging point, the sheet is kept waiting at the position where the downstream end portion of the sheet conveyed in the first sheet conveyance path overlaps. The sheet conveying method according to claim 3. Image forming means for forming an image on a sheet;
The sheet conveying apparatus according to claim 1 or 2, wherein the sheet is conveyed,
An image forming apparatus comprising:

Images