JP2940994B2 - Image forming device - Google Patents

Description

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

(Prior Art) Recently, in the field of copiers, 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 composite copying and screen copying. Next, in the case of double-sided copying, the transfer paper fed from the intermediate tray is again turned upside down by the second flapper and conveyed to the transfer position. In the case of 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 direction of the transfer paper to one.
The second conveyance can be performed in the same manner as the first conveyance to reduce the image disturbance.

(Problems to be Solved by the Invention) However, in such a conventional image forming apparatus, for the following reason, after the image forming operation is completed,
There is a problem that it takes a long time from the start of the next image forming operation to the start of the operation.

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, when starting the image forming operation, the feeding of the transfer paper from the sheet feeding cassette is started only after instructing the start of the image forming operation,
It takes a long time from the start command of the image forming operation to the transfer of the developed image to the transfer sheet at the transfer position, and the above-described problem occurs.

Therefore, the present invention conveys the transfer paper of the large-capacity second transfer paper mounting means to the registration roller via the conveyance direction reversing means before the command signal is input to the start signal input means. It is another object of the present invention to shorten the time from the end of the image forming operation to the start of the next image forming operation until the start of the operation.

(Constitution of the Invention) In order to achieve the above object, an image forming apparatus according to the present invention has an image carrier and an image forming means for forming a latent image on the image carrier and developing the latent image to form an image. A first transfer paper placing means on which a plurality of transfer papers are placed, and a first transfer paper placing means on which a plurality of transfer papers are placed and more transfer papers can be placed than the first transfer paper placing means. (2) first and second paper feeding means provided corresponding to the first and second transfer paper mounting means for feeding the transfer paper of the corresponding transfer paper mounting means; 1. Transfer means for transferring the developed image of the image forming means to the transfer paper fed by the second paper feed means; and holding the transfer paper fed from the paper feed means at a predetermined position, A registration roller for transporting at a timing, and a transport path between the paper feeding unit and the registration roller, which are provided in a first transport direction from the transfer paper feeding unit. Transport direction reversing means for supplying the fed transfer paper to the registration roller in a second transport direction that retreats while maintaining the paper surface direction with respect to the first transport direction; Control means for selecting and operating one of the paper feeding means and controlling the operation of the registration roller and the conveyance direction reversing means, and a start signal for inputting a command signal for starting an image forming operation and outputting it to the control means. Input means, wherein the control means selects and activates the second paper supply means and activates the conveyance direction reversing means before inputting the command signal from the start signal input means, thereby causing Means for transporting the transfer paper to a registration roller via a transport direction reversing means, and a second transfer paper placing means before a command signal is input to the start signal input means. Transfer paper May be provided.

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

1 to 15 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
4a, a numeric keypad 4b, an operation display unit 4 having a display unit 4c for displaying the set number of sheets and occurrence of a jam, a manual feed tray 5 openably and closably mounted on the front side, and a toner cartridge and a discharge toner tank (not shown) for mounting. And a door unit 7 that is opened and closed with the fulcrums 7a and 7b as fulcrums when supplying transfer paper. The manual feed tray 5 serves as a lid in a normal closed state, and serves as a substantially horizontal manual feed toner when opened to the front side 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 is configured to automatically supply the transfer paper P to the recording unit 8 through the transport path 10 from one of the automatic paper feeding units 9A and 9B. Has become. The automatic paper feeding units 9A and 9B can store a plurality of untransferred transfer papers P with the paper surface placed substantially vertically and a larger number of transfer papers P than the paper supply cassette 11A. A paper feed cassette 11B, and pick-up rollers 12A and 12B mounted on the paper feed cassettes 11A and 11B so as to pick up the uppermost transfer paper P among the plurality of transfer papers P placed on the paper feed cassettes 11A and 11B. The paper feed rollers 13A, 13B housed in the door unit 7 to supply the transfer paper P picked up by the pickup rollers 12A, 12B to the transport path 10.
And Therefore, the paper feed cassette 11A is
The transfer paper placing means is constituted, and the paper feed cassette 11B constitutes the second transfer paper placing means. Further, a pickup roller 12A and a paper feed roller 13A are provided corresponding to the paper feed cassette 11A to feed the transfer paper P of the corresponding paper feed cassette.
The sheet feeding means is constituted, and the pickup roller 12B and the sheet feeding roller 13B are provided corresponding to the sheet feeding cassette 11B to constitute the second sheet feeding means for feeding the transfer sheet P of the corresponding sheet feeding cassette.

Although not described in detail because the recording unit 8 has a known configuration, the recording unit 8 includes 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 feed units 9A and 9B, and a transfer fed from the automatic paper feed units 9A and 9B. The paper P is transported from a predetermined position to the transfer charger 19, and the 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 are heated to fix the image. The fixing roller 22 includes a fixing roller 22 that constantly rotates in the sheet discharging direction, a transfer belt 23 that transfers the transfer sheet P from the transfer charger 19 to the fixing roller 22, and the like. 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. Further, the registration rollers 21
In order to control the transfer timing of the transfer paper P, the transfer paper P is intermittently rotated in synchronization with the rotation of the photosensitive drum 14.

As shown in FIG. 3, the transport path between the automatic paper feed sections 9A and 9B and the registration rollers 21 is composed of the transport path 10 and the switchback transport path 30, and the transport 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 automatic sheet feeder 9A, an arrow D ₁ direction through the conveying path 10 from 9B transfer paper 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
By making the horizontal level of the transfer paper discharge position of the transfer roller and the transfer paper transfer start position of the registration roller 21 substantially the same, 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 about 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 between the transfer paper P to be conveyed and the transfer roller P 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 opened. 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, and a DC power supply.
82, AC driver 83 for driving lamps and heaters, motor controller 8 for controlling the driving of the various rollers described above
4. Connected to the various solenoids and actuators such as solenoids, ROM 85, and non-volatile RAM 86. CP
U81 controls the operation of the present apparatus by transmitting and receiving signals between the above-described connections, as described later. Further, the CPU 81 appropriately executes a program according to the flowcharts of FIGS. 8 and 9 stored in the ROM 85, thereby turning on the power of the DC power supply 82.
One of the sheet feeding means including the pickup roller 12 and the like is selected and operated, and the operations of the registration roller 21 and the switchback mechanism 31 are controlled, and constitute control means. 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 the command signal to the CPU 81, and constitutes a start signal input unit.

Before inputting the command signal from the copy start button 4a, the CPU 81 sets up the pickup roller 12B and the sheet feeding roller 1B.
Select and operate 3B and switch back mechanism 31
Is operated, and the transfer paper of the paper feed cassette 11B is transported to the registration roller 21 via the switchback mechanism 31.

Further, the display unit 4c of the display unit 4 has a function of displaying the paper size of the transfer paper P in the paper feed cassette 11B before a command signal is input to the copy start button 4a according to a command from the CPU 81. Yes, and constitutes display means.

Next, the operation will be described with reference to the flowcharts of FIGS. 8 and 9 and FIGS. Note that S1 to S18 in FIGS.
Indicates each step of the flowchart.

First, in S1 of FIG. 8, 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 in a series of copy operations is fed from the automatic sheet feeding units 9A and 9B, 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, control of various image forming operations described later is executed. On the other hand, when copying is not being performed in S2, the process proceeds to S6, and in S6, when the transfer paper P is detected by the switchback sensor 35, that is, it is detected that the transfer paper P is already waiting at the registration roller 21. Proceeds to S5, and if not detected, proceeds to S4.

In the standby mode, in S7 of FIG. 9, the paper supply solenoid, the paper supply clutch and the drive motor of the large-capacity automatic paper supply section 9B are operated to start paper supply by the automatic paper supply section 9B (FIG. 10). (A)). Next, in S8, when the transfer sheet P being moved is detected by the relay sensor 34, the process proceeds to S9. At S9, the contact / separation roller 37 is separated from the friction pad 36 (10th
(FIG. 9B) In S10, the transfer paper P is detected by the switchback sensor 3
If detected by 5, the process proceeds to S11. Next, in S12, the count of the timer T1 is started, and in S12, T1 becomes T1 = t.
When it reaches 1, the process proceeds to S13. Here, t1 is t1 ≧ transfer time between the switchback sensor 35 of the transfer paper P and the nip of the contact / separation roller 37. Next, in S13, the contact / separation roller 37 is brought into contact with the friction pad 36, and the contact / separation roller 37 is rotated forward (FIG. 10 (c)). Next, when the rear end of the transfer sheet P is detected by the intermediate sensor 34 in S14, the process proceeds to S15. Then, in S15,
The contact / separation roller 37 is reversed (FIG. 10 (d)), 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 of the transfer sheet P between the relay sensor 34 and the registration roller 21 nip.
Next, in S18, the drive motor of the contact / separation roller 37 is stopped, and the display unit 4c of the operation display unit 4 displays
The paper size of the transfer paper P placed on A is displayed, and the standby mode is ended (FIG. 10 (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. 11 (a) and 11 (b), the transfer sheet P placed on the sheet feed cassette 11B is conveyed to the relay roller 29 by the sheet feed roller 13B due to the copy start. You. 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, the top transfer paper P
Enters the nip of the contact / separation roller 37,
Abuts on the friction pad 36 and rotates as shown in FIG. 11 (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. 11 (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, the contact / separation roller 37 is separated from the friction pad 36, and the second transfer sheet P is continuously conveyed by the relay roller 29 and the leading end thereof is It enters between the friction pad 36 and the uppermost transfer paper P. Next, when the trailing edge 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 is moved to the friction pad.
The sheet is rotated as shown in FIG. 11 (f) in contact with 36, and the switchback operation of the second transfer sheet P is started.

Clamping and Switchback Next, as shown in FIGS. 12 (a) to 12 (h), the transfer paper P having a different size from the transfer paper P waiting before the registration roller 21, for example, the transfer on the paper feed cassette 11A. When the paper P is selected, the transfer paper P waiting before the registration roller 21 is separated from the registration roller 21 by the rotation of the contact / separation roller 37, and when the rear end in the traveling direction is detected by the switchback sensor 35, the clamper 39 moves and the roller moves
37 is reversed as shown in FIGS.
Is held by the clamper 39 after a predetermined time. The paper feed roller 13A conveys the uppermost paper of the transfer paper P stacked on the paper feed cassette 11B to the relay roller 29. Next, when the leading end of the uppermost paper transfer paper P is detected by the relay sensor 34, the contact / separation roller 37 separates from the friction pad 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 is
When the rear end of the transfer sheet P passes through the backflow prevention member 33, the transfer roller P rotates as shown in FIG.
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. Further, 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 This is because has become a _{f> μ p.}

Next, as shown in FIGS. 13A to 13C, 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, double-sided stacking, and refeeding On the other hand, after the recorded image is fixed by the fixing roller 22, the discharged transfer paper P is double-sided re-fed by switching the discharge switching claw 53 to the double-sided refeed path 55. The sheet is carried into the paper path 55, and is conveyed and stacked by the approach roller 57 until its leading end hits the leading end stopper 59. If the mode is not the duplex copy mode, the transfer paper P is discharged to the discharge tray 3. Here, the jogger fences 58A and 58B
When a plurality of sheets are stacked, the sides of the transfer sheets P are aligned in conjunction with the stacking operation one by one, and the registration in the lateral direction with respect to the refeeding direction is adjusted. When the two-sided copy mode starts, first, the leading end stopper 59 falls down, copying on one side is completed, and the transfer sheets P stacked at the re-feeding position are sent to the pickup roller 61 by the recall roller 60 and separated one by one. Then, it is transported to the switchback transport path 30. Then, the conveyed transfer paper P is turned over for the first time by the switchback mechanism 31, and is in a state where the back side can be copied. The transfer paper P on which the back side copying has been completed is output to the discharge tray 3
The paper discharge tray 3 is moved by the paper discharge switching claw 53 switched to the
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 (for example, 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.

Thus, in this embodiment, after the main switch is turned on, the copy start button of the operation display unit 4
Before 4a is turned ON, the transfer paper P in the paper feed cassette 11B capable of placing a large amount of transfer paper is conveyed to the registration roller 21 and is on standby.
The image forming operation can be started immediately after the 4a is turned ON, and the time from the next ON of the copy start button 4a to the start of the image forming operation after the end of the image forming operation can be shortened. This is because, in general, when at least one of the plurality of paper cassettes is a paper cassette capable of storing large-capacity transfer paper, the large-capacity paper cassette is frequently used. This is because transfer paper of a high paper size is placed.

Further, since the paper size of the transfer paper P put on standby by the registration roller 21 is displayed on the display unit 4c of the operation display unit 4, the operator can always recognize the paper size of the selected transfer paper P. If you want to select a transfer paper P different from the standby paper size,
Before turning on 4a, you can select a paper tray of another paper size.

(Effect) According to the present invention, before the command signal is input to the start signal input means, the transfer paper of the large-capacity second transfer paper placing means is transported to the registration roller via the transport direction reversing means. Since the standby state is set, the image forming operation can be started immediately after the command signal is input, and after the image forming operation is completed, the time from the start of the next image forming operation to the start of the operation is shortened. be able to.

[Brief description of the drawings]

1 to 13 are views showing an embodiment of an 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 thereof, FIG. 3 is an enlarged view of a main part thereof, FIG. 4 is a structural view of a solenoid mechanism for vertically moving the transport roller, FIG. 5 is an enlarged view of a main part of the switchback mechanism, FIG. FIG. 6 is a perspective view of the manual feed tray unit, FIG. 7 is a block diagram of the control unit, FIGS. 8 and 9 are flowcharts of a program for holding the transfer paper, and FIGS. is there. 4a: Copy start button (start signal input means), 4c: Display unit (display means), 11A: Paper cassette (first transfer paper placing means), 11B: Paper cassette (second transfer paper) Mounting means), 12A ... Pick-up roller, 13A ... Feed roller (feed means), 12B ... Pick-up roller (feed means), 13B ... Feed roller, 14 ... Photoconductor drum (image bearing) 18) Image forming means 19 Transfer charger (transfer means) 21 Registration roller 31 Switchback mechanism (transport direction reversing means) 81 CPU (control means) P ... transfer paper.

Continued on the front page (72) Inventor Kazuhisa Sudo 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (58) Field surveyed (Int.Cl. ⁶ , DB name) B65H 29/58 G03G 15 / 00

Claims (2)

(57) [Claims] 1. An image carrier, an image forming means for forming a latent image on the image carrier, and developing the latent image to form an image, and a first transfer paper carrier on which a plurality of transfer papers are placed Means, a plurality of transfer papers, and a second transfer paper mounting means capable of mounting more transfer papers than the first transfer paper mounting means; and a first and a second transfer paper mounting means. First and second paper supply means for supplying the transfer paper of the corresponding transfer paper mounting means, provided on the transfer paper mounting means, and an image on the transfer paper supplied by the first and second paper supply means. A transfer unit that transfers the developed image of the forming unit, a registration roller that holds a transfer sheet supplied from the sheet supply unit at a predetermined position and conveys the transfer sheet to the transfer unit at a predetermined timing, Between the transfer paper feeding means and the first
Transport direction reversing means for supplying the transfer paper fed in the transport direction to the registration rollers in a second transport direction in which the transfer paper is retracted while maintaining the paper surface direction with respect to the first transport direction; First and second control means for selecting and operating one of the paper feeding means and controlling the operation of the registration roller and the conveyance direction reversing means, and inputting a command signal for starting an image forming operation to the control means. Starting signal input means for outputting, and before the control means inputs the command signal from the starting signal input means, selects and operates the second sheet feeding means and operates the transport direction reversing means. ,
An image forming apparatus, wherein the transfer paper of the paper feeding means is transported to a registration roller via a transport direction reversing means. 2. The apparatus according to claim 1, further comprising a display means for displaying the size of the transfer paper of the second transfer paper placing means before the command signal is input to the start signal input means. Image forming device.