JP2819305B2 - Sheet transport device - Google Patents

Description

The present invention relates to a sheet conveying apparatus, and more particularly, to a conveying path of a duplex unit mounted on an image forming apparatus such as a copying machine.

2. Description of the Related Art Conventionally, as a recording apparatus such as a copying machine or a printer, there is, for example, an automatic double-sided copying machine using an electrostatic recording system. The configuration of an apparatus for performing automatic double-sided copying is roughly classified into two types. Is done.

The first automatic duplex configuration of the S-shaped path arranged in the copier P ₂ shown in FIG. 31 in which the basic structure. In the figure, on the copier P ₂ of the copier platen 152 disposed on the upper portion of the main body 51 is placed a document, the image forming unit by scanning the original by an optical system 156 in the copying machine main body 151 157
The latent image is formed by exposing the photosensitive drum. By developing the latent image, a toner image is formed on the image forming unit 157. A plurality of cassettes 159, 160 and the like accommodating sheets S are provided in the copying machine body 151, and a large number of cassettes 159 in a cabinet 162 provided in the copying machine body 151 are also provided. The sheet S is stored. These sheets S are fed by a sheet feeding unit 165 including rollers, separation rollers, and the like provided in each cassette.

Sheet S fed by sheet feeding means such as sheet feeding section 165
After the toner image is transferred to the transfer unit 166 of the image forming unit 157 and further conveyed to the fixing unit 169 by the conveyance belt 167, the sheet S is heated and pressed to fix the toner image. The paper is discharged onto a discharge tray 172 from a paper discharge unit 171 composed of pairs 170.

Here, when performing double-sided copying in which an image is formed on the front and back surfaces of one sheet S or multiple copying in which two or more document images are formed by superimposing two or more document images on one side of one sheet S, the first copy is performed. The sheet S having the toner image formed on the surface thereof is guided to the branch path 175 via the flapper 173 without being discharged outside the apparatus.
First, in the case of double-sided copying, the sheet S passes through the S-shaped path 176 and is discharged to the intermediate tray 179 by the final discharge roller pair 177. At the time of multiple copying, the S-shaped path 17
It is discharged onto the intermediate tray 179 from the middle of the S-shaped path 176 via the deflecting members 180 and 181 in the middle of 6. Intermediate tray 179
The sheet S stacked on the upper side is separated and fed from the lower side, and further passes through a re-feeding path 182, and the image is again transferred by the transfer unit 166, and is subjected to double-sided copying or multiple copying.

Second automatic duplex configuration of the C-shaped path arranged in the copying machine P ₃ shown in Figure 32 is for a basic configuration. In the figure, the apparatus having the configuration of the C-shaped path forms an image on the first side when performing double-sided / multiplex copying, similarly to the configuration having the basic configuration of the S-shaped path described above. The sheet S is guided to the branch path 175 via the flapper 173. In the figure, reference numeral 161 denotes a manual cassette.

At the time of double-sided copying, the sheet S needs to be stacked on the intermediate tray (sheet storing means) 183 with the image side obtained by the first transfer facing upward, so that the sheet S is once conveyed to the switchback path 186 via the flapper 185. Here, after the switch back, the transport unit 187 above the intermediate tray 183
Sent to Then, the sheet S is fed from the predetermined deflecting members 189, 190 of the conveying unit 187 or the leading-edge discharge roller 191 to the conveying unit 18.
3 is discharged on. At the time of the multiple copy, the sheet S is discharged from the predetermined position of the transport unit 187 onto the intermediate tray 183 without sending the sheet S from the flapper 185 to the switchback path 186.

In both the double-sided copy and the multiple copy, in order to provide an appropriate discharge position depending on the size (length) of the sheet S, a deflection plate 189, which can switch the discharge position to a plurality of positions,
190 is disposed above the intermediate tray 183.

(C) Problems to be Solved by the Invention However, the copying machine P ₂ constituting the above-described S-shaped path
When transport path of the sheet S from the fixing portion 169 to the sheet re-feeding path 182 becomes very long, therefore, the copying machine P ₂ in size, there is a particular disadvantage where the height becomes very large . In addition, since the transport path is long, there is a problem that when a jam occurs, the number of locations where the jam is to be processed increases, and the jam clearing operation is troublesome.

Further, in the case of double-sided copying, since the sheet S discharged to the intermediate tray 179 is aligned in the sheet feeding direction with a certain expectation of the movement action due to the weight of the sheet S and the inclined surface of the intermediate tray 179, the sheet S is aligned. Is discharged to the intermediate tray 179 and a loss time occurs before the refeeding process is started. This is because as the number of performing the duplex copying of the sheets S is small becomes remarkable, there is a disadvantage that reduces the productivity of the copier P ₃ when creating a particular one sided copy.

In the case of the copying machine P ₃ that allows duplex copies by utilizing a C-shaped path, especially when discharging the sheet S of large size (A3, B4, etc.) to the intermediate tray 179, the discharge of the sheet S The position inevitably tends to be away from the leading end stopper position at the time of refeeding. For this reason, due to the strength of the waist of the discharged sheet S or the curl of the leading end of the sheet S, the buckling of the sheet S during the discharging and the leading end of the sheet S curl, and the stacking of the sheet S on the intermediate tray 183 It contained factors that were very unstable in terms of gender.

In addition, a small size (A
4, B5, etc.), the discharge path deflecting plates 189, 190, etc., protrude, so that the interval between the discharge path and the intermediate tray 183 is limited due to the apparatus configuration.
When a conveyance failure occurs in the inside, there is a problem that the jam handling property is remarkably deteriorated.

Therefore, an object of the present invention is to provide a sheet transporting device which solves the above-mentioned problem by providing a reciprocally movable carriage unit substantially above an intermediate tray capable of temporarily storing sheets. It is.

(D) Means for Solving the Problems The present invention is directed to a sheet storage means arranged in the middle of a sheet conveyance path for stacking sheets to be re-fed, and a sheet conveyance direction above the sheet storage means. The sheet is arranged reciprocally within a predetermined range along the direction, receives the sheet to be re-fed from the sheet conveyance path at a position on the upstream side in the sheet conveyance direction, moves the sheet to the downstream side in the sheet conveyance direction while holding the sheet, and And a first path for re-feeding the sheets stored in the sheet storage means, and a sheet being delivered from the carriage unit and re-feeding the sheets. And a second pass for

(E) Operation Based on the above configuration, the re-feeding sheet conveyed from the upstream side of the sheet storage means is held by the carriage unit and conveyed above the sheet storage means to the downstream side, and is related to the sheet size. And is discharged to a predetermined position on the sheet storage means.

When the set number of sheets conveyed for refeeding is one, the carriage unit directly conveys the sheet to the second path without discharging the sheet to the sheet storage unit.

(F) Embodiment Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. The same components as those shown in FIGS. 31 and 32 are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 1 shows a copying machine P ₁ to which the first embodiment of the present invention is applied.
It is a vertical side view. 1 to 5, an intermediate tray discharge sensor 4 and a discharge roller 3 for detecting the sheet S are disposed downstream of the flapper 185, and near the downstream of the discharge roller 3, As will be described later, a first carriage unit 1 for nipping and transporting the leading end of the sheet S and a second carriage unit 2 downstream thereof are provided. These carriage units 1 and 2
Are upper plate 5a and side plates 5b, 5c integrally provided on both sides thereof.
And a rotatable roller pair 6 is disposed on an upper portion of the outer surface of the side plates 5b and 5c, respectively.

The carriage unit 2, in the longitudinal direction (Figure of the copier P ₁ by loosely fitting the roller pair 6 to the guide rails 7 and 8 of the pair which is fixed respectively to both side plates of the copying machine main body 151 (Left / right direction). A pair of belts 9 having both ends connected to the both side plates 5b and 5c of the first carriage unit 1 are wound around pulley pairs 13 and 15 fixed to shafts 11 and 12, respectively. A motor 16 that can rotate forward and backward is connected to an end of the carriage 11, whereby the carriage unit 1 is moved in the direction of arrow 17 or in the direction of arrow 19 opposite thereto. Similarly, a pair of belts 9a, both ends of which are connected to both side plates 5b, 5c of the second carriage unit 2, are wound around a similar pair of pulleys 13a, 15a and reciprocated by another motor 16. Driven freely.

Both ends of the shaft 21 to which the plurality of carriage rollers 20 of the first carriage unit 1 are fixed are connected to side plates of the frame 5.
Bases of a pair of support levers 22 are rotatably mounted on both ends of the shaft 21 extending from the side plates 5b, 5c. Carriage roller 20 above
The plurality of carriage rollers 23 forming a pair are fixed to a shaft 26 rotatably provided on the side plates 5b and 5c. This axis 26
The ends of the support lever 22 penetrate through the long holes 27 formed in the side plates 5b and 5c, respectively, and the long holes 22a formed in the free ends of the support lever 22 are formed.
, And is urged toward the shaft 21 by a spring 22b, that is, in a direction in which the carriage roller 23 is pressed against the carriage roller 20.

The support lever 22 is biased counterclockwise in the figure by a tension spring 29 locked at both ends by the side plate 5b and the support lever 22, and the shaft 26 is driven by the rear end of the elongated hole 27 (the left end in the figure). ) Is stationary in contact with In this state, the carriage roller 23 is in a state of being pressed against the vertical position of the carriage roller 20, as shown in FIG.

An operating lever 30a of a deflecting solenoid 30 is connected to a side edge of the support lever 22 opposite to the spring 29, and when the deflecting solenoid 30 operates at a timing described later,
The support lever 22 rotates clockwise about the shaft 21 as indicated by an arrow 31, and stops in a state where the shaft 26 contacts the front end (the right end in the figure) of the elongated hole 27. In this state, the carriage roller 23 is connected to the carriage roller 20 as shown by a chain line in FIG.
And slightly revolves to the paper feeding direction side (right side in the figure) while being pressed against. Due to the revolution of the carriage roller 23, the tangential direction of the contact portion of the carriage rollers 20, 23, that is, the sheet S
Is slightly downward.

A motor 32 for driving the carriage rollers 20, 23 is fixed to the side plate 5c of the frame 5, and a gear 33 fixed to an output shaft of the motor 32 is connected to a gear 35 fixed to an end of the shaft 21. The gear 35 is in mesh with a gear 36 fixed to the end of the shaft 26.
Is engaged.

A base of an operating member 42 is attached to an appropriate position of the frame 5, and its free end extends upward from the frame 5, and the operating member 42 is moved by a sensor described later when the carriage unit 1 moves. It will be detected. A carriage roller sensor 43 for detecting the sheet S is provided before and after the carriage rollers 20 and 23 of the carriage unit 1.

The second carriage unit 2 also has similar carriage rollers 57 and 59 and is driven by the motor 16, and before and after the carriage rollers 57 and 59, a carriage roller sensor 60 for detecting the sheet S is provided. It is arranged.

In FIG. 2, the carriage units 1 and 2 and the belts 9 and 9a for moving the carriage units are arranged in series as shown. A micro switch for stopping the carriage unit 1 from the vicinity of the pulley 13 along the pulley 15a on the downstream side.
46, 61 and micro switches 62, 47 for stopping the carriage unit 2 are fixedly mounted on the support plate 67,
These microswitches are turned on and off by a notch 5b (see FIG. 3) formed in the upper plate 5a of the frame 5. Further, on the downstream side of the pulley 13, the operating member 42 of the carriage unit 1 is detected. Sensors 83 and 85 and sensors 86 and 87 for detecting the operating member 63 of the carriage unit 2 are fixedly mounted on the support plate 67.

In the above configuration, first, an operation when n sheets (n> 1) of a half-size double-sided copy for one document will be described with reference to FIGS. In FIG. 1, the operation until the sheet S enters the switchback path 186 after the one-sided copy on the sheet S is completed is the same as the operation of the conventional C-shaped path shown in FIG.

The first carriage unit 1 is at a position where the micro switch 46 is turned on as shown in FIG. When the switchback roller 45 and the discharge roller 3 rotate in the directions of the arrows to feed the sheet S toward the carriage unit 1 and the intermediate tray discharge sensor 4 detects the leading end of the sheet S, the carriage rollers 20 and 23 of the carriage unit 1 are detected. Is rotated in the direction of the arrow by the rotation of the motor 32, and the sheet S
The tip of the mouth. At this time, the carriage roller 2
0 and 23 rotate together with the switchback roller 45.

When the carriage roller sensor 43 in the first carriage unit 1 detects that the leading end of the sheet S has been added to the nip portion between the carriage rollers 20 and 23, the motor 32 stops and the rotation of the carriage rollers 20 and 23 is stopped. Stop. Next, the moving motor 16 in FIG. 3 starts rotating, and the first carriage unit 1 starts moving in the direction of arrow 17 in FIG. 6 and moves at the same speed as the peripheral speed of the switchback roller 45. I do. At this time, the second carriage unit 2 is stationary with the micro switch 62 turned on.

When the operating member 42 of the carriage unit 1 moving in the direction of the arrow 17 is detected by the sensor 85, the moving motor 16 of the carriage unit 1 is decelerated, and when the notch 5d is detected by the micro switch 61, the motor A brake (not shown) acts on the carriage 16 and the carriage unit 1 stops as shown in FIG. In this state, the carriage rollers 20, 23 of the first carriage unit 1 and the carriage rollers 57, 59 of the second carriage unit 2 respectively start rotating, and the sheet S is inserted into the carriage unit 2.

The sensor 6 detects that the leading end of the sheet S has been held in the nip between the carriage rollers 57 and 59 of the carriage unit 2.
When detected by 0, the carriage unit 1 moves at the speed v in the direction of arrow 19 and the carriage unit 2 moves at the speed V in the direction of arrow 17 as shown in FIG. The sheet S held by the carriage unit 2 also moves at the speed V in the direction of the arrow 17. The moving speed (process speed) of the sheet S at this time is V.

During the movement of the carriage unit 2, the carriage rollers 57 and 59 of the carriage unit 2 stand still and the sheet S
However, the carriage rollers 20, 23 of the carriage unit 1 rotate at a peripheral speed (V + v). At this time, a one-way clutch (not shown) is interposed in the gear 36 integral with the carriage roller 20 of the carriage unit 1 and there is a slight speed difference in the feeding speed of the sheet S.
Even if the rotation speed of the carriage rollers 20 and 23 does not catch up with the moving speed of the sheet S, the sheet S is not damaged by the action of the one-way clutch.

When the operating member 63 of the carriage unit 2 detects the sensor 87 as shown in FIG. 9 by the movement of the carriage unit 2, a brake (not shown) acts on the carriage unit 2 and the notch 5d turns on the micro switch 47. The carriage unit 2 stops. Further, the deflection solenoid 30 of the carriage unit 2 shown in FIG. 5 is operated, and the carriage roller 57 revolves to the sheet discharge side as shown in FIG. 9, and the discharge port faces slightly downward. , 59 rotate in the directions of the arrows to discharge the sheet S. The carriage unit 2 returns at the speed v in the direction of arrow 19 as shown in FIG. 10 while discharging the sheet S.

At this time, the moving speed of the second carriage unit 2 is v, and the discharge speed of the sheet S is V, so that the carriage rollers 57 and 59 of the carriage unit 2 have a peripheral speed (V + v).
Rotate with. When the carriage unit 2 is discharging the sheet S, the carriage unit 1 holds the next sheet S and moves in the direction of arrow 17. When the discharge of the sheet S on the intermediate tray 183 is completed, a solenoid (not shown) is turned on, the feed roller 65 is lowered, and comes into contact with the sheet S. Next, the deflection solenoid of the carriage unit 2 is turned off, and the carriage roller 59 returns to the original position.

The first and second carriage units 1 and 2 return to the state shown in FIG. 7 and the delivery of the sheet S to the carriage unit 2 is performed again, and the feeding roller 65 is moved to the intermediate tray (sheet storing means) 183. The sheet S is stacked on the intermediate tray 183 away from the sheet S. When the stacking of the sheets S on the intermediate tray 183 is completed, lateral alignment of the stacked sheets is performed by a width shifting motor (not shown). Intermediate tray
The refeeding from 183 is the same as in the conventional apparatus of FIG. 31. The feeding roller 65 is lowered onto the sheet S by a solenoid (not shown) to feed the sheet S, and the downstream separation roller 66 The sheet S is separated and conveyed one by one, and is further conveyed while forming a loop between the second registration roller 70 and the separation roller 66 and between the first registration roller 69 and the second registration roller 70 to form an oblique sheet S. Modify the line.

Next, the operation for copying n sheets (n> 1) of a large-size sheet S into a single document will be described with reference to FIGS.
This will be described with reference to the drawings.

The second carriage unit 2 is retracted to a position away from the home position (where the microswitch 62 is turned ON) by the sheet size signal. The carriage unit 1 is provided with a micro switch 46 as in the case of the half size.
After holding the leading edge of the sheet S at the position where is turned ON, the rotation of the carriage rollers 20 and 23 is stopped, and in this state, the carriage S moves in the direction of arrow 17.

When the carriage unit 1 stops at the position where the micro switch 61 is turned on as shown in FIG. 12, the deflection solenoid 30 shown in FIG. 5 is operated, and the carriage rollers 20 and 23 are turned slightly downward as shown in FIG. When the carriage rollers 20 and 23 rotate in this state, the sheet S is discharged onto the intermediate tray 183. The carriage unit 1 moves in the direction of arrow 19 while discharging the sheet S.

In order for the carriage unit 1 to convey the sheet S at the speed V, if the moving speed of the carriage unit 1 is v, the carriage rollers 20, 23 rotate at a peripheral speed of (V + v). At this time, the next sheet S is
And enters into the switchback roller 45.
When the carriage unit 1 returns to the home position and turns on the micro switch 46, the next sheet S is held by the carriage rollers 20, 23 of the carriage unit 1.

In the conveyance and discharge of the large-size sheet described above, the distance for pushing out the sheet S is extremely reduced as compared with that of the conventional apparatus, so that the stable conveyance to the intermediate tray 183 is performed. Further, since the carriage unit 1 returns to the home position side while conveying the sheet S, the productivity of the sheet conveying device is not reduced at all.

Next, in both the half size and the large size, a case where one double-sided copy is made from one double-sided original and a case where one double-sided copy is made from two single-sided originals are described with reference to FIGS. Will be explained.

The process up to the point where the first carriage unit 1 and the second carriage unit 2 are transferred to the first carriage unit 1 and the second carriage unit 2 via the switchback path 186 is the same as the half-size double-sided copy described above. The micro switch 47 for stopping the carriage unit 2 is connected to an operating member 75a of a solenoid 75 as shown in FIG. 27, and when the solenoid 75 is operated, the micro switch 47 rotates to a position shown by a chain line 47A. It has become. The second carriage unit 2
Move to the place where the micro switch 76 is turned on. in the meantime,
The carriage unit 1 moves in the direction of arrow 19 shown in FIG.

The carriage rollers 57 and 59 of the carriage unit 2 stopped at the position of the microswitch 76 rotate to feed the sheet S between the transport rollers 72 provided in the through-pass unit 71. When the leading end of the sheet S is detected by the sensor 73, the carriage unit 2 returns in the direction of arrow 19 as shown in FIG. 18, and the first carriage unit 1 holds the sheet S and moves in the direction of arrow 17 as shown in FIG. . When the two carriage units 1 and 2 reach the delivery section where the micro switches 61 and 62 are located, the sheet S is delivered from the carriage unit 1 to the carriage unit 2.

The sheet S fed from the intermediate tray 183 is sent to the re-feeding path via the first path 71A. The transport path of the through path 71 as the second path is shorter than that of the first path 71A.

The sheet S conveyed from the through-pass unit 71 is conveyed while forming a loop between the conveyance roller 72 and the first registration roller 69. When the sheets S are stacked on the intermediate tray 183, the sheets S are temporarily in a free state. On the other hand, when the sheets S pass through the through-pass section 71, the sheets S are constantly restrained. One time is enough.

When the image formation of the sheet S is in the multiplex mode, the sheet S of any size is not moved through the switchback path 186 by the operation of the flapper 185 as shown in FIG. In addition.

The sheet S by the carriage units 1 and 2 described above
20 to 22 are collectively shown in the flowcharts of FIGS. 20 to 22. In the figure, the reference numeral HP indicates a home position, which means a place where the micro switch 46 is turned on in the case of the first carriage unit 1 and a place where the micro switch 62 is turned on in the case of the second carriage unit 2. .

FIG. 20 is a flowchart of an operation of stacking half-size sheets S on the intermediate tray 183, in which n (n> 1) double-sided copies are made from one document. No.
FIG. 21 is a flowchart in the case where the sheet S passes through the through path, and FIG. 22 is a flowchart of the operation of stacking the large-size sheet S on the intermediate tray 183.
11 is a flowchart in a case where n-sided (n> 1) double-sided copying is performed from one document.

In the embodiment described above, the two-carriage type sheet conveying device is used. However, the carriage that conveys and discharges the sheet S may be a single carriage unit 1 like the sheet conveying device shown in FIG. Then, as shown in FIG. 29, the carriage units 1 and 2 shown in FIG.
In addition to the above, for example, a third carriage 93 may be provided downstream of the carriage unit 2 to provide two or more carriages. The carriage 93 is reciprocally movable by a belt 95 wound around a pair of pulleys similarly to the carriage units 1 and 2, and conveys and discharges the sheet S transferred from the carriage unit 2. Perform

FIG. 26 is a block diagram of a control operation when the sheet S is conveyed and discharged. A signal input to the I / O input unit is output from the I / O output unit via the CPU, and the carriage unit
The control of conveyance and discharge of the sheet S by 1 and 2 is performed.

FIG. 25, FIG. 23 and FIG. 24 show a second embodiment of the present invention. The duplex unit of the image forming apparatus shown in FIG. 25 is provided with a through-pass unit 71 for making one copy from one document.

Even without the through-pass unit 71, it is possible to configure the sheet conveying device of the present invention, in this case,
N copies (n>) from one original described in the first embodiment
As in the case of 1), even in the case of one copy from one original, as shown in FIGS.
Discharge on 183.

As shown in FIG. 23, the time when the leading end of the sheet S passes under the sheet feeding roller 65 is watched by a timer, and the feeding roller 65 is lowered by a solenoid (not shown), as shown in FIG. The sheet S is fed again by rotating the sheet feeding roller 65 and the separation roller 66 at the same speed as the speed of the sheet S.
Since the separation roller 66 performs torque limiter separation, there is no problem in transporting one sheet.

In the above-described embodiment, the case where the present invention is applied to the intermediate tray 183 of the copying main body 151 has been described. However, the same effect can be obtained when the present invention is applied to the circulating document feeder.

Here, a case where the present invention is applied to a recirculating document feeder (hereinafter referred to as RDF) will be described.

FIG. 30 shows a longitudinal side view of the RDF. In the figure, an original 101 is placed on the original tray 102 with the original surface facing upward, and the original 101 is sent to the separation section B from the lowermost portion by the half-moon roller 103 and the weight 105. The separating section B includes a separating belt 106 and a feeding roller 107, and thereby separates one sheet at the lowermost position.

The separated document 101 enters the path 110 and collides with the registration roller 109, forms a predetermined loop, and is conveyed to the platen 117 on the main body side by the registration roller pair 109. Belt 111 wound around driving roller 113 and driven roller 112
The belt 111 is pressed against the platen 117 by a plurality of press rollers 115. The document 101 sent between the platen 117 and the belt 111 is conveyed to a predetermined position at the end (the left end in FIG. 30) of the platen 117 by the movement of the belt 111 and stops.

Here, the original 101 is read by reading means (not shown) such as an optical system of the copying machine main body. When the predetermined reading of the document 101 is completed, the belt 111 moves again and sends the document 101 into the path 119. And the original 101 is the large roller 120
The first carriage unit
The document is delivered from the second carriage unit 122 to the second carriage unit 122, and is set on the uppermost portion of the loaded document 101 with the document face down. Hereinafter, the same operation as the above operation is performed for the remaining documents 101
To complete the copying of one copy with the plurality of originals 101.

Note that the path 123 is a path for reversing the two-sided original, and the reference numeral 125 is its switching flapper, which is not directly related to the present invention.

The first carriage unit 121 and the second carriage unit 122 have the same roller pair as the carriage units 1 and 2 described above, and can transport the document 101 between the roller pair, and at the same time, the RDF Is guided by an elongated hole 126 formed in the side plate of the side plate and is movable in forward and reverse directions shown by arrows. With the first carriage unit 121 and the second carriage unit 122, the document 101 can be transported and discharged with the document 101 held therebetween.

The detailed operation of these carriage units 121 and 122 is the same as the operation of the intermediate tray 183 of the above-described embodiment, thereby improving the RDF jam clearance property with the copying machine P _1.
Can be improved as well.

As described above, according to the above-described embodiment, since the mechanism for transporting the sheet is constituted by the carriage unit 1 (2) which can reciprocate above the intermediate tray 183, the sheet S is transported by the intermediate tray 183. When a jam occurs, the jam state of the sheet S is estimated by recognizing the jam signal of the copying machine body 151 and the jam position by the sensor, and the carriage unit 1 is moved to a position corresponding to the jam to stand by. By the middle tray 183
The upper side is open, allowing the user to easily handle the jam sheet.

Further, since the carriage unit 1 is configured to be able to be positioned at an arbitrary position on the intermediate tray 183, for example, a plurality of discharge positions from the carriage unit 1 to the intermediate tray 183 may be set in response to a change in the size of the sheet S or the like. This can be implemented without providing the deflecting means, and the apparatus can be simplified. Further, in terms of sheet stackability, for example, by controlling the discharge speed of the carriage rollers 20 and 23 in the carriage unit 1, the carriage unit 1 can be transported in the reverse direction during discharge of the sheet S. This makes it possible to bring the discharge position from the carriage unit 1 to the intermediate tray 183 as close as possible to the re-feed entrance regardless of the size (length) of the sheet S. Therefore, it is possible to suppress the degree of freedom of the sheet leading end while the leading end of the sheet reaches the re-feeding entrance, and it is possible to prevent a stacking defect due to only a stiffness when a large-sized (weak) sheet S is stacked. In addition, at the time of double-sided copying, it is possible to prevent the sheet from being caught with the leading edge of the next stacked sheet S due to the toner condition on the image surface of the already stacked sheet.

Further, in the conventional stationary discharge path, the sheet discharge operation cannot be changed in accordance with the information on the number of sheets S discharged to the intermediate tray 183. For this reason, when a large number of double-sided copies are performed, the discharge condition of the sheet S varies depending on the level change of the uppermost stacked surface of the already loaded sheets, and it is difficult to obtain a stable stack from a small number of sheets to a large number of sheets. However, in the configuration of the present embodiment, the discharge position of the carriage unit 1 can be moved by a very small amount in accordance with the number of sheets information (physical characteristics of the sheet), and the carriage roller in the carriage unit 1 can be moved. The angles of 20, 23 can be changed in accordance with the number information (physical characteristics of the sheets), and the sheets S can always be stably supplied into the intermediate tray 183 from an appropriate discharge position and discharge angle. Becomes This improves the stackability of the sheets S on the intermediate tray 183.

In addition, sheet transport / conveyance in the conventional stationary discharge path
Noise such as mechanical sudden sound and rubbing noise between the guide plate and the sheet front end in the apparatus having the stacking structure is drastically reduced by employing the carriage unit transport / stacking mechanism of the present embodiment.

(G) Effects of the Invention As described above, according to the present invention, a sheet to be re-fed is conveyed from the sheet conveyance path, received by the carriage unit, conveyed to a predetermined position on the downstream side, and stored. When only one sheet is stored on the sheet storage means and the sheet is re-fed, the carriage unit moves the sheet to the second path without discharging the sheet onto the sheet storage means. Since the sheet is discharged to the sheet storage means, the sheet can be quickly re-fed as compared with the case where the sheet is re-fed through the first pass.
The productivity of sheet conveyance can be improved.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view of an image forming apparatus to which a sheet conveying apparatus according to a first embodiment of the present invention is applied, and FIG. 2 is a micro switch for controlling first and second carriage units and their positions. FIG. 3 is a perspective view of a driving unit of a first (second) carriage, and FIG.
FIG. 5 is a front view of the carriage, FIG. 5 is a perspective view of a deflecting mechanism of the carriage roller, FIGS. 6 to 10 are operation diagrams when half-size sheets are stacked on the intermediate tray, and FIGS.
FIG. 15 is an operation diagram when stacking large-size sheets on the intermediate tray, FIGS. 16 to 19 are operation diagrams when one-sheet copy is set, and FIGS. 20 to 22 are flowcharts of sheet conveyance / discharge operations. FIG. 25 is a longitudinal sectional side view of an image forming apparatus to which a sheet conveying apparatus according to a second embodiment of the present invention is applied, and FIG.
Fig. 24 is the same operation diagram, Fig. 26 is a block diagram of the sheet conveyance / discharge control of the present invention, and Fig. 27 is a micro switch.
47 is a side view, FIG. 28 and FIG. 29 are longitudinal side views of an image forming apparatus to which a modification of the present invention is applied, and FIG. Fig. 31
FIG. 32 is a vertical side view of a conventional image forming apparatus having an S-shaped transport path, and FIG. 32 is a vertical side view of a conventional image forming apparatus having a C-shaped transport path. S ...... sheet, P ₃ ...... copier (image forming apparatus), 1 ......
A first carriage, 2... A second carriage unit,
3: discharge roller, 46, 47, 61, 62, 76 ... micro switch, 51, 83, 85, 86, 87 ... sensor, 71 ... through path (second path), 71A ... first Pass, 93 ... Carriage, 1
83 …… Intermediate tray.

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Yuji Takahashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-59-83146 (JP, A) JP-A-2 198960 (JP, A) Fully open sho 56-23949 (JP, U) Fully open sho 60-130252 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B65H 29/22 B65H 29/10 B65H 85/00 G03G 15/00 106

Claims (3)

(57) [Claims] 1. A sheet storage means disposed in the middle of a sheet conveyance path for stacking sheets to be re-fed, and reciprocally movable in a predetermined range along the sheet conveyance direction above the sheet storage means. A carriage that receives a sheet that is placed and re-fed from the sheet conveyance path at a position on the upstream side in the sheet conveyance direction, moves to the downstream side in the sheet conveyance direction while holding the sheet, and carries the sheet into the sheet storage unit. A first path for re-feeding the sheets stored in the sheet storage means, and a second path for receiving and re-feeding the sheets from the carriage unit. A sheet conveying device comprising: 2. The sheet conveying apparatus according to claim 1, wherein an entrance of said second path is provided at substantially the same height as a sheet discharging means provided on said carriage unit. 3. The carriage unit receives a sheet to be re-fed from the sheet conveyance path at a position on the upstream side in the sheet conveyance direction, and is movable in a predetermined range to the downstream side in the sheet conveyance direction while holding the sheet. An upstream carriage unit, a downstream carriage unit that receives a sheet from the upstream carriage unit, moves downstream in a sheet conveying direction while holding the sheet, and loads the sheet into the sheet storage unit; The sheet conveying device according to claim 1, wherein the sheet conveying device comprises: