JP2816703B2 - Sheet transport device - Google Patents

Description

The present invention relates to a sheet storage device, and more particularly, to a conveyance 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 an automatic double-sided copying machine using, for example, an electrostatic recording method. The configuration of an apparatus for performing automatic double-sided copying is roughly classified into two. Is done.

The first automatic duplex configuration of the S-shaped path arranged in the copier P ₂ shown in FIG. 22 in which the basic structure. In the figure, on the copier P ₂ of the copier platen 152 disposed in an upper portion of the main body 151 is placed a document, the image forming unit by scanning the original by an optical system 156 in the copying machine main body 151 Fifteen
A latent image is formed by exposing the photosensitive drum 7 to light. 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 storing sheets S are arranged in the copying machine body 151, and a large number of sheets are stored in a storage section 163 in a cabinet 162 in which the copying machine body 151 is mounted. Of sheets S are 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, in the case of a screen copy in which an image is formed on the front and back surfaces of one sheet S or a multiple copy in which two or more original 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 FIG. 23 in which the basic structure. 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 a proper discharge position depending on the size (length) of the sheet S, a deflection plate 189 that can switch the discharge position to a plurality of positions is provided.
190 is disposed above the intermediate tray 183.

(C) SUMMARY OF THE INVENTION However, multiple machine P ₂ constituting the S-shaped path described above
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 of the sheet S by its own weight with the inclined surface of the intermediate tray 179, A loss time occurs before S is discharged to the intermediate tray 179 and 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 ₂ 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 conveying apparatus capable of stably loading sheets on an intermediate tray regardless of the sheet size.

(D) Means for Solving the Problems The present invention provides a sheet storage means arranged in the middle of a sheet conveyance path for stacking sheets to be re-fed and a sheet storage direction above the sheet storage means. A sheet that is re-fed is received from the sheet conveyance path at a position on the upstream side in the sheet conveyance direction, and can be moved to the downstream side in the sheet conveyance direction while holding the sheet. An upstream carriage unit, and a transport unit that transports the sheet received from the upstream carriage unit, so that the upstream carriage unit can reciprocate downstream in the sheet transport direction and along the sheet transport direction. And the downstream transporter is capable of moving to the downstream side in the sheet transport direction while holding the sheet and discharging the sheet to the sheet storage unit. Cartridge unit, an upstream drive unit that reciprocates the upstream carriage unit, and a downstream drive unit that reciprocates the downstream carriage unit, and the downstream drive unit controls the downstream carriage unit. The unit is moved to a certain discharge start position regardless of the sheet size, and after the sheet is started to be discharged by the conveying means at the position, the downstream carriage unit discharges the sheet to the upstream side in the sheet conveying direction. Moving.

(E) Function Based on the above configuration, the carriage unit on the upstream side
The sheet reciprocates in a predetermined range above the sheet storage means and on the upstream side, and is conveyed to the upstream side above the sheet storage means for re-feeding. The downstream carriage unit receives the sheet for re-feeding from the upstream carriage unit, and reciprocates in a predetermined range above the sheet storage means and on the downstream side to cooperate with the upstream carriage unit. Then, it is carried into the sheet storage means.

The discharge of the sheet by the downstream carriage unit is started at a fixed discharge start position irrespective of the size of the sheet, and after the start of the sheet discharge, the downstream carriage unit is moved upstream in the sheet conveying direction, that is, the sheet is conveyed. The sheet moves while discharging the sheet in the direction opposite to the direction.

(F) Example Hereinafter, a first example of the present invention will be described with reference to FIGS. Note that the same components as those shown in FIGS. 22 and 23 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 (upstream carriage unit) 1 for nipping and transporting the leading end of the sheet S and a second carriage unit (downstream carriage unit) 2 downstream thereof are provided. ing. Each of the carriage units 1 and 2 has a frame 5 composed of a bottom plate 5a and side plates 5b and 5c integrally provided on both sides of the bottom plate 5a. A rotatable roller pair is provided on the upper outer surface of the side plates 5b and 5c. 6 are provided 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 8, 8 a pair of fixedly mounted on each side plate in 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 the same pair of pulleys 13a, 15a and driven by another motor 16. You.

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
A plurality of carriage rollers 23 forming a pair with each other, and a plurality of seating rollers 25 located between the carriage rollers 23 and having an outer diameter longer than the outer diameter of the carriage rollers 23 are fixed to shafts 26, respectively. ing. Both ends of this shaft 26 are side plates
5b, penetrate through the elongated holes 27 formed in 5c, respectively, is attached to the elongated hole 22a formed at the free end of the support lever 22,
The spring 22b biases the shaft 21 toward the shaft 21, that is, the 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 a position perpendicular to 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, as shown in FIG. 7, the carriage roller 23 slightly revolves in the sheet feeding direction (right side in the figure) while being pressed against the carriage roller 20. Due to the revolution of the carriage roller 23, the tangential direction of the contact portion between the carriage rollers 20, 23, that is, the discharge direction of the sheet S becomes slightly downward.

A motor 32 for driving the carriage rollers 20 and 23 is fixed to the side plate 5c of the frame 5, and a gear 33 fixed to an output shaft thereof is fixed to ends of the shafts 21 and 26, respectively. Connected to gear 36.

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 detects a sensor described later when the carriage unit 1 moves. To operate. A roller sensor 43 for detecting the sheet S is provided before and after the carriage rollers 20, 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 the above configuration, first, an operation when making a half-size double-sided copy 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.

As shown in FIG. 6, the first carriage unit 1
It is at the position where the HP sensor 46 is turned ON. Switchback roller
When the sheet S is sent to the carriage unit 1 by rotating the ejection roller 45 and the ejection roller 3 in the direction of the arrow, and the intermediate tray ejection sensor 4 detects the leading end of the sheet S, the carriage rollers 20 and 23 of the carriage unit 1 The rotation of 32 rotates each in the direction of the arrow to hold the leading end of the sheet S. At this time, the switchback roller 45 rotates together with the carriage rollers 20 and 23.

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, the first carriage unit 1 starts moving in the direction of arrow 17, and the switchback roller 45 has the same speed as the moving speed of the carriage unit 1. It rotates at the peripheral speed of. At this time, the second carriage unit 2 is stationary with the sensor 62 turned on.

When the carriage unit 1 and the operating member 42 moving in the direction of the arrow 17 are detected by the sensor 61, a brake (not shown) acts on the motor 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, the gear 36 integral with the carriage roller 20 of the carriage unit 1 has a slight speed difference because a one-way clutch (not shown) is interposed.
Even if the rotation speeds of 20, 23 cannot catch up with the moving speed of the sheet S, the sheet S will not be damaged by the action of the one-way clutch.

The movement of the carriage unit 2 causes the operating member 63 of the carriage unit 2 to move as shown in FIG.
Is detected, a brake (not shown) acts on the carriage unit 2 and the carriage unit 2 stops. Also, the deflection solenoid of the carriage unit 2 shown in FIG. 5 acts to cause the carriage roller 57 to revolve to the sheet discharge side as shown in FIG. 10 and the discharge port faces slightly downward, and in this state, the carriage roller 57, 59 rotates in the directions of the arrows to discharge the sheet S. The carriage unit 2
The sheet S 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 discharging 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 onto the intermediate tray 183 is completed, a solenoid (not shown) is turned on, the feed roller 65 is lowered, and the sheet S
Abut on top. Next, the deflection solenoid of the carriage unit 2 is turned off, and the carriage roller 59 returns to the original position.

The carriage units 1 and 2 and the carriage roller 20,
23, 57, 59 and the like are controlled by a control circuit (not shown) by a control circuit (not shown) so that the operation corresponding to the half-size sheet S is performed.

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 moves away from the sheet S on the intermediate tray 183. And sheets S are stacked on an intermediate tray (sheet storage means) 183. 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 the sheet S is 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 oblique light. Modify

Next, the operation when stacking large-sized sheets S will be described with reference to FIGS.

As shown in FIG. 11, the first and second carriage units 1 and 2 are stopped with the sensors 46 and 83 turned on, respectively, and the sheet S sent from the switchback roller 45 is transferred to the carriage unit 1 and the carriage. Hold in unit 2.

As shown in FIG. 12, the carriage unit 2 moves to the position where the sensor 47 is turned on while holding the leading end of the sheet S, and during that time, the carriage rollers 20, 23 and the switchback roller 45 of the carriage unit 1 It rotates in accordance with the speed of S (the speed of the carriage unit 2). Carriage rollers 57, 5 of carriage unit 2
9 is a solenoid 30 and a support lever 2 as shown in FIG.
The sheet S is fed by turning downward and rotating by the deflecting means such as 2. At this time, the carriage unit 1 stops the rotation of the carriage rollers 20 and 23 and moves together with the carriage unit 1 at the same speed as the sheet S.

A timer measures the timing at which the leading end of the sheet S comes below the feed roller 65, and after the leading end comes down, a solenoid (not shown) is turned on to lower the feed roller 65 onto the sheet S. Then, rotate as shown in FIG.
A solenoid (not shown) for lowering the feed roller 65
When turned on, the carriage unit 1 and the carriage unit 2 move in the direction of arrow 19 while rotating the carriage rollers 20, 23, 57, 59. At this time, it is preferable that the carriage unit 2 returns faster than the carriage unit 1 as much as possible so that the trailing edge of the sheet S does not drop when the carriage unit 1 separates from the sheet S. The peripheral speed of the carriage rollers 57 and 59 is the speed of the sheet S + the moving speed of the carriage unit 2. After the sheet S is discharged to the intermediate tray 183, the next sheet S is held as shown in FIG.

The carriage units 1 and 2 and the carriage roller 20,
23, 57, 59, etc. are controlled by a control circuit (not shown) by a control circuit (not shown) so that the operation corresponding to the large-size sheet S is performed.

A second embodiment of the present invention will be described with reference to FIGS. 16 to 21 as an operation of a large size sheet.

As shown in FIG. 16, the carriage unit 2 stands by at the place where the sensor 62 is turned on, as in the case of the half size. The carriage unit 1 includes carriage rollers 20 and 23
Rotates and stops the rotation after holding the sheet S, and in this state, moves to a position where the sensor 61 is turned ON as shown in FIG. The carriage unit 1 transfers the leading end of the sheet S to the carriage unit 2 and
Move in the direction of arrow 19 while rotating.

The carriage unit 2 moves in the direction of arrow 17 and turns on the sensor 47, and returns to the direction of arrow 19 as shown in FIG. 18 while rotating the carriage rollers 57 and 59 to discharge the sheet S. As shown in FIG. 19, immediately before the discharge of the sheet S is completed, the switchback roller 45 starts rotating and starts feeding the next sheet S toward the carriage unit 1. Immediately after the sensor 83 is turned on, the carriage unit 2 moves in the direction of arrow 17 shown in FIG. 20 to the state shown in FIG.
17 to 21 are repeated until the stacking of a predetermined number of sheets S is completed.

(G) Effects of the Invention As described above, according to the present invention, a sheet conveyed from a sheet conveyance path is conveyed downstream to a conveyance path above a sheet storage means for storing a sheet to be re-fed. And a downstream carriage unit that conveys and discharges the sheet received from the upstream carriage unit to the downstream side, and the downstream carriage unit is located at the same position regardless of the sheet size. The sheet starts to be ejected, and after the sheet is ejected, the sheet is moved to the upstream side in the sheet conveying direction while the sheet is being conveyed. Position of the sheet for re-feeding at a predetermined position of the sheet storage means regardless of the sheet size. And be Rukoto, not only can improve the sheet stacking property of the sheet storage means, it is possible to shorten the time for re-feeding the sheet.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view of an image forming apparatus to which a first embodiment of a sheet conveying apparatus according to the present invention is applied, and FIG.
Perspective view of the second carriage unit and its driving unit,
FIG. 4 is a plan view, FIG. 4 is a front view of a carriage unit and rails, FIG. 5 is a perspective view showing a deflecting unit of the carriage unit, and FIGS. FIG. 11 to FIG. 15 are operation diagrams when a large-size sheet is conveyed, FIG. 16 to FIG. 21 are operation diagrams when a large-size sheet is conveyed showing a second embodiment of the present invention, FIG.
FIG. 23 is a vertical sectional side view of a conventional image forming apparatus having an S-shaped sheet conveying apparatus, and FIG. 23 is a vertical sectional side view of a conventional image forming apparatus having a C-shaped sheet conveying apparatus. S ...... sheet, P ₃ ...... copier (image forming apparatus), 1 ...... first carriage unit (upstream side of the carriage unit), 2 ...... second carriage unit (downstream side of the carriage unit), 3 … Ejection roller, 4… Intermediate tray ejection sensor, 20,23,57,59… Carriage roller, 43,60… Carriage roller sensor, 46,47,51,61,62… Carriage position detection sensor , 183
...... Intermediate tray.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yuji Takahashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-59-83146 (JP, A) JP-A-62 −196235 (JP, A) Fully open 1981--23949 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B65H 29/22 B65H 85/00 G03G 15/00 106

Claims (1)

(57) [Claims] 1. A sheet storage means arranged in the middle of a sheet conveyance path for stacking sheets to be re-fed, and a reciprocating movement in a predetermined range along the sheet conveyance direction above the sheet storage means. An upstream carriage unit that receives the sheet to be re-fed from the sheet conveyance path at a position on the upstream side in the sheet conveyance direction and is capable of moving the sheet to the downstream side in the sheet conveyance direction while holding the sheet; Transporting means for transporting the sheet received from the carriage unit on the upstream side, and disposed so as to be able to reciprocate along the sheet transporting direction on the downstream side in the sheet transporting direction of the upstream carriage unit, and wherein the transporting means is A carriage unit on the downstream side capable of moving to the downstream side in the sheet conveyance direction while holding the sheet and discharging the sheet to the sheet storage unit; An upstream drive unit that reciprocates the carriage unit; and a downstream drive unit that reciprocates the downstream carriage unit. The downstream drive unit allows the downstream carriage unit to be moved regardless of the sheet size. Moving the carriage unit on the downstream side while discharging the sheet to the upstream side in the sheet conveying direction after moving the sheet to a certain discharge start position and starting discharging the sheet by the conveying unit at the position. Sheet conveying device.