JP2821013B2 - Image forming device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an image forming apparatus, for example, an image forming apparatus applied to a copying machine.

[Conventional technology]

Recently, in the field of copying machines, which are image forming apparatuses,
There is a high demand for improved image quality and higher operation speed.

As a conventional image forming apparatus of this type, for example,
There is one described in Japanese Patent Publication No. 60-13863. In this type, an image is formed by transferring a transfer sheet accommodated in a paper feed cassette to a predetermined transfer position and transferring a developed image on an image carrier. Also, this is provided on the downstream side of the fixing device.
A flapper is provided, and the transfer paper once transferred by the first flapper is fed to the intermediate tray at the time of the composite copying and the duplex copying. Next, in the case of double-sided copying, the sheet is again turned upside down by the transfer paper second flapper fed from the intermediate tray and conveyed to the transfer position. Further, in the case of the composite copying, the transfer paper fed again from the intermediate tray is fed to the switchback transport means by switching the second flapper, and the switchback transport means changes the paper surface direction of the transfer paper by one.
The second conveyance can be performed in the same manner as at the time of the second conveyance, and the image disturbance is reduced.

[Problems to be solved by the invention]

However, in such a conventional image forming apparatus, when a plurality of paper feed cassettes on which transfer papers are placed are provided, the start of the image forming operation is instructed for the following reason. There has been a problem that the time until the start of operation is long.

That is, although the conventional image forming apparatus is provided with an intermediate tray and a switchback transport unit, the transfer paper is transferred between the intermediate tray and the switchback transport unit after the start of the image forming operation is instructed and before the operation is started. There is no function to keep the means on standby. For this reason, even if a desired paper cassette can be selected from a plurality of paper cassettes before the image forming operation is started, the transfer from the selected paper cassette is not performed until the start of the image forming operation is instructed. Paper feeding is started. Therefore, the time from the start of the image forming operation to the start of the transfer operation becomes longer, and the above-described problem occurs.

[Object of the invention]

Therefore, the present invention provides a method for selecting and activating a paper feeding means corresponding to a transfer paper placing means selected by a selection signal inputting means before a command signal is input to a start signal inputting means, and a conveying direction reversing means. To transfer the transfer paper fed to the paper feeding means to the registration roller via the feeding direction reversing means, thereby shortening the time from the start of the image forming operation to the start of the operation. It is an object.

[Configuration of the invention]

In order to achieve the above object, an image recording apparatus according to the present invention includes: an image forming unit that forms a latent image corresponding to an image of a document on an image carrier and develops the latent image to form an image; A plurality of transfer paper placement means placed thereon, a plurality of paper supply means provided corresponding to the plurality of transfer paper placement means, and paper supply means for feeding the transfer paper of the corresponding transfer paper placement means; Transfer means for transferring the developed image of the image forming means to the transfer paper supplied by the printer, and a registration roller for holding the transfer paper supplied from the paper supply means at a predetermined position and conveying the transfer paper to the transfer means at a predetermined timing. ,
The transfer paper provided in the transport path between the paper supply means and the registration roller and fed in the first transport direction from the transfer paper mounting means holds the paper surface direction with respect to the first transport direction. The conveyance direction reversing means for supplying the registration rollers to the second conveyance direction, which retreats, while selectively operating one of the plurality of paper feeding means and controlling the operation of the registration rollers and the conveyance direction reversing means. Control means for performing
Start signal input means for inputting a command signal to start an image forming operation and output the control signal to the control means, and control by inputting a command signal for selecting one of the plurality of transfer paper mounting means from the plurality of transfer paper mounting means. Selection signal input means for outputting to the means, the control means, before inputting the command signal from the start signal input means, input a command signal from the selection signal input means, by the selection signal input means The paper feeding means corresponding to the selected transfer paper placing means is selected and operated, and the transport direction reversing means is operated, so that the transfer paper fed by the paper feeding means is registered via the transport direction reversing means. The transfer sheet is transported to a registration roller and waits before the control means inputs a command signal from the start signal input means. A display means for displaying a message may be provided.

 Hereinafter, the present invention will be described based on examples.

1 to 14 are views showing an embodiment of the image forming apparatus according to the present invention.

 First, the configuration will be described.

In FIG. 1, reference numeral 1 denotes a main body of a copying machine, which is an image forming apparatus. The main body 1 of the copying machine includes a document table 2 provided on an upper portion thereof, and copy (recorded) transfer paper discharged from the inside. Tray 3 on which the document is placed, and a copy start button
Various input keys such as 4a, numeric keypad 4b, and enter key 4c, and a display section for displaying various information such as a set number of sheets and occurrence of a jam.
4d, an operation display unit 4 having a manual feed tray 5 mounted on the front side so as to be openable and closable, a mounting portion 6 for mounting a toner cartridge and a toner discharge tank (not shown), and a fulcrum portion 7a for replenishing transfer paper. , 7b which are opened and closed with the fulcrum as a fulcrum. The manual feed tray 5 serves as a lid in a normal closed state, while it serves as a substantially horizontal manual feed tray when opened toward the front in the figure, and guides transfer paper manually fed from outside (for details, see FIG. See below).

2 (a) and 2 (b), reference numeral 8 denotes a recording unit. The recording unit 8 includes a conveyance path from any one of the automatic paper feeding units 9A, 9B, and 9C.
The transfer paper P is automatically fed through 10. The automatic paper feed units 9A to 9C are described by omitting the reference numerals A, B, and C, respectively. However, the automatic paper feed units 9A to 9C are provided with a plurality of paper feed cassettes 11 ( Transfer paper mounting means) and a pick-up roller 12 mounted on the paper feed cassette 11 so as to pick up the uppermost transfer paper P among the plurality of transfer papers P mounted on the paper feed cassette 11.
And a plurality of paper feed rollers 13 housed in the door unit 7 so as to supply the transfer paper P picked up by the pickup rollers 12 to the transport path 10. A pickup roller 12 and a paper feed roller 13 are provided corresponding to the plurality of paper feed cassettes 11, and constitute paper feed means for feeding the transfer paper P of the corresponding paper feed cassette.

Although not described in detail because the recording unit 8 has a known configuration, an image forming unit 18 including a photosensitive drum 14 serving as an image carrier, a charging charger 15, an exposure optical system 16, and a developing unit 17; A transfer charger 19 (transfer unit) for transferring the developed image of the image forming unit 18 to the untransferred transfer paper P fed by the paper units 9A to 9C, and a transfer paper fed from the automatic paper feed units 9A to 9C P is transported from a predetermined position to the transfer charger 19, and a registration roller 21 for controlling the transport timing of the transfer paper P, and the transfer paper P on which the developed image has been transferred by the transfer charger 19 is heated to fix the image. A fixing roller 22 that constantly rotates in the sheet discharging direction, and a transport belt that transports the transfer paper P from the transfer charger 19 to the fixing roller 22
It is composed of 23 mag. Here, the image forming means 18 reflects the photosensitive drum 14 charged by the charging charger 15 to a document reflecting image information including image information by an exposure optical system 16 including first and second scanners 24 and 25 including a light source and a plurality of mirrors. After exposure to light to form a latent image on the photosensitive drum 14, the latent image is developed by the developing unit 17 to form a visible image (developed image) on the photosensitive drum 14. The registration roller 21 is provided with a photosensitive drum for controlling the transfer timing of the transfer paper P.
It rotates intermittently in synchronization with the rotation of 14.

As shown in FIG. 3, the conveyance path between the automatic paper feeding units 9A to 9C and the registration rollers 21 is constituted by the conveyance path 10 and the switchback conveyance path 30, and the conveyance path 10 is controlled by a relay roller 29. This is a passage for guiding the transfer paper P to the switchback conveyance path 30. The switchback transport path 30 is provided with a switchback mechanism 31. The switchback mechanism 31 is specifically formed of a flexible material (for example, Mylar),
The backflow preventing member 33, which is supported in a cantilever manner on the guide plate 32 at the connection part of the connection plate 30 in such a manner as to allow only the transfer of the transfer sheet P from the transfer path 10 to the switchback transfer path 30, and the transfer sheet P passes therethrough. The relay sensor 34 is installed to detect the displacement of the other end of the backflow prevention member 33 at the time of the transfer, and detects that the transfer paper P is carried into the switchback conveyance path 30; A switchback sensor 35 for detecting the transport state of the paper P, a friction pad 36 formed of foamed polyurethane rubber or the like, and arranged substantially at the center of the switchback transport path 30, and formed of, for example, a no-solex rubber; A contact / separation roller 37 that rotates forward and reverse at a position vertically opposed to the friction pad 36 with the switchback conveyance path 30 interposed therebetween, and the contact / separation roller 37 approaches and separates from the friction pad 36, A contact / separation solenoid mechanism 38 (see FIG. 4) which can pinch and release the transfer paper P between the two, and is driven by a solenoid (not shown) or the like to oscillate. And a clamper 39 which can clamp the leading end of the transfer paper P sent out to the registration roller 21 from the guide plate 32. This switchback mechanism 31
The arrow D ₁ direction through the conveying path 10 from the automatic sheet feeder 9A~9C the transfer sheet P fed to the (first transport direction), forward of the contact and separation roller 37 (in the figure, clockwise rotation) by while carrying the switchback conveyance path 30, the arrow to retract while maintaining the paper orientation relative D ₁ direction by the reverse rotation of the contact and separation roller 37
D Supply the resist roller 21 in the ₂ direction (second transport direction) (hereinafter, this is also simply referred to as switchback).
It is a conveyance direction reversing means, and the switchback mechanism 31
The transfer sheet discharge position of the transfer roller P and the transfer paper transfer start position of the registration roller 21 are made substantially the same so that the transfer paper P held by the registration roller 21 becomes substantially horizontal when the registration roller 21 stops. I have to. In addition,
As shown in FIG. 4, the contact / separation solenoid mechanism 38 includes a solenoid 41 that moves the plunger 41a in the axial direction, and a rotating member 4 that rotates around a fulcrum 42a in response to the solenoid 41.
2, a supporting member 43 attached to the rotating member 42 and rotatably supporting the contact / separation roller 37, and a frame of the copying machine main body 1.
1a and a spring 44 stretched between the rotating members 42. As shown in FIG. 5, the friction coefficient of the transfer paper P to be conveyed to the contact / separation roller 37 is μ _r , the friction coefficient between the transfer papers P is μ _p , and the transfer paper P clamped by the clamper 39 is when the friction coefficient of the friction pad 36 and mu _f, mu
Select a material of the friction pad 36 and contact and separation roller 37 so that _{r> μ f> μ p,} the transfer sheet P so that the other transfer sheet P while being clamped can be switched back by the clamper 39 . In this embodiment, 0.4
_{<Μ p <0.7, μ r} > 1.6,1.0 <μ f is <1.2.

Again, in FIG. 2, on the downstream side of the fixing roller 22,
A separation claw 51, a paper discharge sensor 52, and a paper discharge switching claw 53 are provided. The separation claw 51 peels off the transfer paper P from the fixing roller 22 at the tip of the claw brought close to the fixing roller 22.
The paper discharge sensor 52 detects the presence or absence and passage of the transfer paper P at the exit side of the fixing roller 22, and sends paper discharge information to the controller. The discharge switching claw 53 closes one of a single-side discharge path 54 from the fixing roller 22 to the discharge tray 3 and a double-sided re-feed path 55 that descends from the fixing roller 22 and joins the transport path 10 again. At the same time, the other is opened, and the two passages 54 and 55 are switched. Further, a part of the double-sided re-feeding path 55 is formed by the manual feed tray 5, and when the manual feed tray 5 is opened in the arrow B direction in FIG. The lower part of the paper feed passage 55 is a manual paper feed passage. Specifically, as shown in FIGS. 2 and 6, the double-sided paper re-feeding path 55 is formed by the manual feed tray 5 and the guide member 56 opposed thereto, and the manual feed tray 5 is normally And functions as a manual feed tray only when the manual feed is in the open state. At the bottom of the double-sided re-feed path 55, a sponge roller 5
7, a pair of jogger fences 58A, 58B, tip stopper 5
9, a feeding roller 60, a pick-up roller 61, and a tray sensor 62 are installed, and the transfer paper P that has entered the duplex re-feeding path 55 from the fixing roller 22 is constantly moved in the re-feeding direction. Stacked in place by the jogger fences 58A, 58B and the tip stopper 59, transported again by the call roller 60 and the pickup roller 61, and the call roller 60
The sheet is again fed to the transport path 10 by the pickup roller 61. The tray sensor 62 detects the presence and the width of the transfer paper P stacked in front of the leading end stopper 59 at the time of double-sided copying, and detects that the transfer paper P has been inserted into the manual feed tray 5 at the time of single-sided copying. Further, an open / close sensor 63 is provided on the upper side of the double-sided refeed path 55, and the open / close sensor 63 is provided.
Detects opening and closing of the manual feed tray 5. Then, based on the detection signal of the open / close sensor 63, the manual feed tray 5 is locked by a tray lock (not shown) so as not to open in the closed state during the copying operation.

Here, FIG. 7 shows a control section for controlling the operation of the present apparatus. In FIG. 7, reference numeral 81 denotes a CPU composed of a microcomputer. The CPU 81 includes the operation display unit 4, the above-described various sensors such as photosensors and switches, a DC power supply 82, and an AC driver 83 for driving lamps and heaters. , A motor controller that controls the driving of the various rollers described above
84, which are connected to the various solenoids and actuators such as the solenoid, the ROM 85, and the nonvolatile RAM 86. CP
U81 controls the operation of the present apparatus by transmitting and receiving signals between the above-described connections, as described later. The CPU 81 appropriately executes a program according to the flowcharts of FIGS. 9 and 10 stored in the ROM 85, thereby turning on the DC power supply 82,
One of the paper feeding means including a plurality of pickup rollers 12 and the like is selected and operated, and the registration roller 21 is operated.
And controls the operation of the switchback mechanism 31 and constitutes control means. On the other hand, the copy start button 4a of the operation display unit 4 is for inputting a command signal for starting an image forming operation by an operator's operation and outputting it to the CPU 81, and constitutes a start signal input means. further,
Numeric keypad 4b and enter key 4c of operation display unit 4
Is for inputting a command signal for selecting one of the paper feed cassettes among the paper feed cassettes 11A, 11B and 11C and outputting it to the control means, and constitutes a selection signal input means. More specifically, each of the paper cassettes 11A, 11B, and 11C corresponds to the “1”, “2”, and “3” keys of the numeric keypad 4b. For example, when the paper cassette 11A is selected, “ When the "#" key of the enter key 4c is pressed after the "1" key is pressed, the selection of the paper feed cassette 11A is input. Further, this selection input operation may be input by operating a dip switch (not shown).

Before inputting the command signal from the copy start button 4a, the CPU 81 sets the numeric keypad 4b and the enter key 4c.
The pickup roller 12 and the paper feed roller 13 corresponding to the selected paper feed cassette 11 are selected and operated by inputting a command signal from the controller, and the switchback mechanism 31 is operated to operate the pickup roller 12 and the paper feed roller 13. The transfer paper P fed by 13 is conveyed to the registration roller 21 via the switchback mechanism 31 and made to stand by.

Further, the display unit 4d of the display unit 4 constitutes display means for displaying the size of the transfer paper P which is conveyed to the registration roller 21 and is waiting before the CPU 81 inputs a command signal from the copy start button 4a. . Specifically, in FIG. 8, the numbers 1, 2, and 3 indicated by K correspond to the sheet cassettes 11A, 11B, and 11C, respectively, and to the right of each number, the size of the transfer paper P of each sheet cassette 11 Is displayed, and from which paper cassette 11 the transfer paper P waiting on the registration roller 21 is indicated by blinking of the corresponding numeral (FIG. 8 shows a state where 1 blinks). Is). Further, the frame line L in FIG. 8 surrounds the number, paper size, and the like corresponding to the selected paper feed cassette 11, and indicates the currently selected paper feed cassette 11.

Next, the operation will be described with reference to the flowcharts of FIGS. 9 and 10 and FIGS. Note that S1 to S18 in FIGS.
Indicates each step of the flowchart.

First, in S1 of FIG. 9, the DC is operated by operating the main switch.
When the power source 82 is turned on, it is determined in S2 whether copying is being performed, that is, whether an image is being formed, and if copying is in progress, the process proceeds to S3. S3
When the final transfer sheet P in a series of copy operations is fed from the automatic sheet feeding unit 9, the process proceeds to S4. In S4, the standby mode before the start of the image forming operation described below is executed, and in S5, the control of various image forming operations described later after the start of image formation is executed. On the other hand, when copying is not being performed in S2, the process proceeds to S6. In S6,
If the transfer sheet P is detected by the switchback sensor 35, that is, if it is detected that the transfer sheet P is already waiting at the registration roller 21, the process proceeds to S5, and if not, the process proceeds to S4.

In the standby mode, in S7 of FIG. 10, for example, the paper supply solenoid, paper supply clutch, and drive motor of the automatic paper supply unit 9C corresponding to the paper supply cassette selected by operating the numeric keypad 4b and the enter key 4c are operated. , Automatic paper feeder 9C
(FIG. 11 (a)). Then, S8
When the transfer sheet P being moved is detected by the relay sensor 34, the process proceeds to S9. In S9, the contact / separation roller 37 is separated from the friction pad 36 (FIG. 11 (b)), and in S10, the transfer paper P
Is detected by the switchback 35, the process proceeds to S11.
Next, in S12, counting of the timer T1 is started. When T1 becomes T1 = t1 in S12, the process proceeds to S13. However,
t1 is t1 ≧ (moving time between the nip of the switchback sensor 35 of the transfer paper P and the contact / separation roller 37). Then, S13
Then, the contact / separation roller 37 is brought into contact with the friction pad 36 to rotate the contact / separation roller 37 forward (FIG. 11 (c)). Then, S1
In 4, when the rear end of the transfer paper P is detected by the intermediate sensor 34, the process proceeds to S15. Next, in S15, the contact / separation roller 37 is reversed (FIG. 11 (d)), and the count of the timer T2 is started in S16, and when T2 = t2 in S17, the process proceeds to S18. Here, t2 is t2 ≧ (movement time between the relay sensor 34 of the transfer paper P and the nip of the registration roller 21). Then, S18
Then, the drive motor of the contact / separation roller 37 is stopped, the paper size of the transfer paper P placed on the paper feed cassette 11C is displayed on the display unit 4d of the operation display unit 4, and the standby mode is ended (the first mode). FIG. 11 (e).

Next, various controls executed in S5 of FIG. 8 will be specifically described.

Switchback First, the copy start button 4a of the operation display unit 4
Is turned on, as shown in FIGS. 12 (a) and 12 (b), the transfer sheet P placed on the sheet feeding cassette 11C is conveyed to the relay roller 29 by the sheet feeding roller 13C by the copy start. . The transfer paper P held by the registration roller 21 and waiting is conveyed to the photosensitive drum 14 at a predetermined timing by the rotation of the registration roller 21, and is sent to the fixing roller 22 after the transfer is completed. Next, when the uppermost transfer paper P enters the nip of the contact / separation roller 37, the contact / separation roller 37 contacts the friction pad 36 and rotates as shown in FIG. 12 (c). When the rear end of the transfer paper P passes through the backflow prevention member 33, the contact / separation roller 37 is rotated in the reverse direction as shown in FIG. 12 (d), and the transfer paper P is switched back. The paper feed roller 13C starts feeding the second transfer paper P after a predetermined time. Next, when the second transfer sheet P is detected by the relay sensor 34, as shown in FIG.
Is separated from the friction pad 36, and the second transfer sheet P continues to be conveyed by the relay roller 29, and its leading end enters between the friction pad 36 and the uppermost transfer sheet P. Next, when the trailing end of the uppermost transfer paper P comes out of the nip of the contact / separation roller 37 with the rotation of the registration roller 21, the contact / separation roller 37 comes into contact with the friction pad 36 and FIG.
And the switchback operation of the second transfer sheet P is started.

When a transfer sheet P having a different size from the transfer sheet P waiting in front of the registration roller 21, for example, a transfer sheet P on the sheet cassette 11 </ b> A is selected by an operation of an operator or the like, the registration roller When the transfer paper P which has been waiting in front of it is separated from the registration roller 21 by the rotation of the contact / separation roller 37, and the rear end in the traveling direction is detected by the switchback sensor 35, the clamper
39 operates and the contact / separation roller 37 moves as shown in FIG. 13 (a).
(B) As shown in (c), the transfer paper P is reversed and held by the clamper 39 after a predetermined time. The paper feed roller 13A conveys the top sheet of the transfer paper P stacked on the paper feed cassette 11A to the relay roller 29. Next, the top paper transfer paper P
When the relay sensor 34 detects the leading end of the friction pad, the contact / separation roller 37 is moved to the friction pad as shown in FIG.
36, and prepares for insertion of the transfer paper P. When the transfer paper P enters the nip of the contact / separation roller 37, the contact / separation roller 37 comes into contact with the friction pad 36 and rotates as shown in FIG. After passing through 33, the contact / separation roller 37 is reversed, and the transfer paper P is switched back. The transfer paper P continues to be conveyed by the relay roller 29, and its leading end enters between the transfer paper P held by the clamper 39 and the contact / separation roller 37. FIG. 13 (f)
(G) As shown in (h), the feed roller 13A starts to convey the second transfer sheet P after a predetermined time. Here, on the transfer sheet P can separate the transfer paper P is switched back in a state where the transfer sheet P is clamped in the clamper 39, the relationship between the friction coefficient between each as described above is mu _r> mu _f > μ
_{This is because p} .

Next, as shown in FIGS. 14A to 14C, the holding of the transfer paper P by the clamper 39 is released, and the transfer is performed by rotating the contact / separation roller 37 clockwise in the drawing. Paper P is clamper
39, and the rear end of the transfer paper P is
, The clamper 39 rotates downward and the contact / separation roller 37 rotates counterclockwise, and the transfer paper P reaches the nip of the registration roller 21 and stops.

Discharge, screen stacking, and refeeding On the other hand, after the recording image is fixed by the fixing roller 22, the discharged transfer paper P is re-feeded on both sides by switching the discharge switching claw 53 to the duplex re-feeding path 55 side. It is carried into passage 55,
The sheet is conveyed and stacked until the front end thereof abuts against the front end stopper 59 by the approach roller 57. If the mode is not the duplex copy mode, the transfer paper P is discharged to the discharge tray 3. Here, when the plurality of transfer papers P are stacked, the jogger fences 58A and 58B align the sides of the transfer papers P in conjunction with the stacking operation one by one, and register the transfer papers P in the lateral direction with respect to the refeeding direction. To match. When the two-sided copy mode is started, first, the leading end stopper 59 falls down, the copy on one side is completed, and the transfer paper P stacked at the refeed position is started.
Is sent to the pickup roller 61 by the call roller 60,
The sheets are separated one by one and transported to the switchback transport path 30. Then, the transferred transfer paper P is first inverted by the switchback mechanism 31, and is ready for backside copying. The transfer paper P on which the back side copying has been completed is discharged to the discharge tray 3 by the discharge switching claw 53 switched to the discharge tray 3, and a series of copying operations is completed. In the present embodiment, the size of the transfer paper P to be stacked on both sides is set to A6.
(Postcard) to A4Y (Y is horizontal), LT (letter size) -Y (however, the length is 216 mm or less), and transfer paper longer than that (examples are B4, A4-T, A3 etc)
Is preferably a single-sided double-sided copy.

When the manual feed tray 5 is opened horizontally, this is detected by the open / close sensor 63, and the manual feed mode is set. The discharge switching claw 53 is switched to the discharge tray 3 side, and at the same time, the selection of the duplex mode cannot be made. Then, the approach roller 57 moves upward, the jogger fences 58A and 58B recede to both sides, and the plurality of manually-inserted transfer papers P are stacked at a position where the leading ends abut the leading end stopper 59. At this time, the presence or absence of the transfer paper P and the paper width are detected by the tray sensor 62, and then,
The jogger fences 58A and 58B return to the size position of the transfer sheet P, and align the sides of the transfer sheet P. Note that the jogger fences 58A and 58B may be manually operated. The stacked transfer paper P is sent to the pickup roller 61 by the recall roller 60 when the leading end stopper 59 falls forward at the same time as the start of sheet feeding, separated and sent to the relay roller 29, and is transferred to the switchback conveyance path 30. Conveyed.

As described above, in this embodiment, the main switch is turned on.
Later, before the copy start button 4a of the operation display unit 4 is turned on, the ten key 4b and the enter key 4c
After the main switch is turned on or the image forming operation is completed, the copy start button 4a is turned on, and the image forming operation is started. The time until the operation starts can be reduced.

Further, since the paper size of the transfer paper P that is kept on standby by the registration roller 21 is displayed on the display unit 4d of the operation display unit 4, the operator can always recognize the paper size of the selected transfer paper P. .

Further, the transfer paper P of the desired paper feed cassette 11 can be made to stand by on the registration roller 21 by the operation of the ten key 4b and the enter key 4c by the user as a user. By selecting the paper cassette 11 on which P is placed, copy productivity can be improved with a reduction in the time from the ON of the copy start button 4a to the start of the image forming operation.

〔effect〕

According to the present invention, before the command signal is input to the start signal input means, the transfer paper of the transfer paper placing means selected by the selection signal input means is conveyed to the registration roller and made to stand by, so The time from the start of the forming operation to the start of the operation can be shortened.

[Brief description of the drawings]

1 to 14 are views showing an embodiment of the image forming apparatus according to the present invention. FIG. 1 is an external perspective view of the image forming apparatus, and FIG.
(B) is a cross-sectional view, FIG. 3 is an enlarged view of the main part, FIG. 4 is a configuration diagram of a solenoid mechanism for moving the transport roller up and down, and FIG. 5 is a main part for explaining the switchback mechanism. FIG. 6 is a perspective view of the manual feed tray unit, FIG. 7 is a block diagram of the control unit, FIG. 8 is an enlarged view of a main part of the operation display unit, and FIGS. The flowchart of the program to be put on standby, and FIGS. 4a ... copy start button (start signal input means), 4b ... numeric keypad (selection signal input means), 4d ... enter key (selection signal input means), 4d ... display section (display means), 11A, 11B, 11C: paper feed cassette (transfer paper loading means), 12A, 12B, 12C ... pickup roller (paper feed means), 13A, 13B, 13C ... paper feed roller (paper feed means), 14: photoconductor Drum (image carrier), 18 image forming means, 19 transfer charger (transfer means), 21 resist roller, 31 switchback mechanism (transport direction reversing means), 81 CPU (control means) ), P ... Transfer paper.

Continuation of the front page (72) Inventor Kazuhisa Sudo 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (56) References JP-A-4-93848 (JP, A) JP-A-64-34821 (JP, A) JP-A-1-269949 (JP, A) JP-A-63-35749 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B65H 7/18 B65H 3 / 44 342 B65H 29/58 B65H 9/14

Claims (2)

(57) [Claims] An image forming means for forming a latent image corresponding to an image of a document on an image carrier and developing the latent image to form an image; a plurality of transfer paper mounting means on which transfer paper is mounted; A plurality of paper feeding means provided corresponding to the plurality of transfer paper mounting means for feeding the transfer paper of the corresponding transfer paper mounting means, and an image forming means on the transfer paper fed by the paper feeding means Transfer means for transferring the developed image, a registration roller for holding the transfer paper fed from the paper supply means at a predetermined position and conveying the transfer paper to the transfer means at a predetermined timing, and a transfer roller between the paper supply means and the registration roller. The transfer paper provided in the transport path and fed back from the transfer paper mounting means in the first transport direction is moved backward in the second transport direction while maintaining the paper surface direction with respect to the first transport direction. Conveying direction reversing means for supplying the resist rollers toward
A control means for selecting and operating one of the plurality of paper feeding means and controlling the operation of the registration roller and the conveyance direction reversing means; and starting input of a command signal for starting an image forming operation and outputting to the control means Signal input means;
Selection signal input means for inputting a command signal for selecting one of the plurality of transfer paper mounting means from among the plurality of transfer paper mounting means and outputting the command signal to the control means, Inputting the command signal from the selection signal input means, and selecting and operating the sheet feeding means corresponding to the transfer paper placing means selected by the selection signal input means before inputting the command signal of An image forming apparatus, comprising: activating a reversing means to convey a transfer sheet fed by the sheet feeding means to a registration roller via a conveying direction reversing means and to stand by. 2. A display device for displaying the size of a transfer sheet which is conveyed to a registration roller and is on standby before a control signal is inputted from said start signal input means by said control means. Item 2. The image forming apparatus according to Item 1.