JPH0494349A - Image formation device - Google Patents

Abstract

PURPOSE:To shorten the time from the giving of an image formation operation com mand to the starting of the operation by feeding a decalcomania paper sheet in a decalcomania paper sheet storing means selected by a selection signal input means, to a resist roller and making it stand-by, before a command signal is input to a start ing signal input means. CONSTITUTION:Before a copy start button is pushed, a pickup roller 12, and a feeding roller 13 corresponding to a feeding cassette 11 selected by the operation of a ten-key as well as an enter-key, are operated. When a decalcomania paper sheet P under transfer is detected by an intermediate sensor 34, a connection/disconnection roller 37 is separated from a friction pad 36, and when the decalcomania paper sheet P is detected by a switch back sensor 35, a timer is started, and after a preset period of time has passed, the connection/disconnection roller 37 is abutted on the friction pad 36, and the connection/disconnection roller 37 is rotated normally, so as to feed the decalcomania paper sheet P to a switch back feeding route 30. When the rear end of the decalcomania paper sheet is detected by an intermediate sensor 34, the connection/disconnection roller 37 is reversed, and the decalcomania paper sheet P is fed to a resist roller 21. After a predetermined period of time has passed after the timer is started, the connection/disconnection roller 37 is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an image forming apparatus, and for example, to an image forming apparatus applied to a copying machine.

[Prior Art] Recently, in the field of copying machines, which are image forming devices, there has been a strong demand for improved image quality and increased operating speed.

As a conventional image forming apparatus of this type, for example,
There is one described in Publication No. 0-132863. This device conveys transfer paper stored in a paper feed cassette to a predetermined transfer position and transfers a developed image on an image carrier to form an image. Further, in this device, a first flapper is provided on the downstream side of the fixing device, and during composite copying and double-sided copying, the first flapper feeds the transfer paper that has been transferred once to the intermediate tray. Next, in the case of double-sided copying, the transfer sheet is again fed from the intermediate tray, reversed by the second flapper, and conveyed to the transfer position. In addition, in the case of composite copying, the transfer paper fed again from the intermediate tray is fed to the switchpuncture conveyance means by switching the second flapper, and the paper surface direction of the transfer paper is adjusted by the switchpuncture conveyance means for the first time. The second conveyance is performed in the same manner as the conveyance, in order to reduce image disturbance.

[Problem B to be Solved by the Invention] However, in such a conventional image forming apparatus, when a plurality of paper feed cassettes carrying transfer paper are provided, for the reasons mentioned above, the image There was a problem that it took a long time from when the command to start the forming operation was given until the start of the operation.

In other words, conventional image forming apparatuses are equipped with intermediate trays and switchhuck conveyance means, but between the time when the start of image forming operation is commanded and the start of the operation, the transfer paper is not transferred to the intermediate tray or switchhook conveyance means. There is no function to keep the device on standby. Therefore, even if it is possible to select the desired paper feeding power from multiple paper cassettes before starting the image forming operation, the selected paper cassette is Feeding of transfer paper begins. Therefore, the time from the start of the image forming operation to the start of the transfer operation becomes longer, causing the above-mentioned problems.

[Object of the Invention] Therefore, the present invention provides a method for selecting and operating the paper feeding means corresponding to the transfer paper mounting means selected by the selection signal input means before a command signal is input to the start signal input means. At the same time, the conveying direction reversing means is activated, and the transfer paper fed to the sheet feeding means is conveyed to the registration rollers via the conveying direction reversing means. The purpose is to save time.

[Structure of the invention]

In order to achieve the above object, an image recording apparatus according to the present invention includes an image forming means for forming a latent image corresponding to an image on a document on an image carrier and developing the latent image to form an image, and a transfer paper. A plurality of transfer paper mounting means placed thereon, a plurality of paper feeding means provided corresponding to the plurality of transfer paper mounting means and feeding the transfer paper of the corresponding transfer paper mounting means, and a paper feeding means. a transfer unit that transfers the developed image of the image forming unit to the transfer paper fed by the paper feed unit; and a registration roller that holds the transfer paper fed from the paper feed unit at a predetermined position and conveys it to the transfer unit at a predetermined timing. ,
Provided on the conveyance path between the paper feeding means and the registration roller, and holding the transfer paper fed in the first conveyance direction from the transfer paper mounting means in the direction of the paper surface with respect to the first conveyance direction. a conveying direction reversing means that supplies the registration rollers in a second conveying direction in which the paper is moved backward, and one of the plurality of paper feeding means is selected and operated, and the operation of the registration rollers and the conveying direction reversing means is controlled. a control means for inputting a command signal to start an image forming operation and outputting it to the control means; and a command signal for selecting one of the plurality of transfer paper mounting means. selection signal input means for inputting and outputting to the control means,
Before the control means inputs the command signal from the start signal input means, the control means inputs a command signal from the selection signal input means and feeds paper corresponding to the transfer sheet placement means selected by the selection signal input means. The method is characterized in that the means is selected and activated, and the conveying direction reversing means is activated, so that the transfer paper fed by the sheet feeding means is conveyed to the registration rollers via the conveying direction reversing means and is kept on standby. Further, before the control means inputs the command signal from the start signal input means, a display means may be provided for displaying the size of the transfer sheet that has been conveyed to the registration rollers and is waiting.

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

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

First, the configuration will be explained.

In FIG. 1, 1 is the main body of a copying machine, which is an image forming device. output tray 3 on which the paper is placed, and copy start button 4
Various input keys such as a, numeric keypad 4b, enter key 4c, etc.
and an operation display unit 4 having a display section 4d for displaying various information such as the set number of sheets and jam occurrence, a manual feed tray 5 attached to the front side so as to be openable and closable, and for mounting a toner cartridge and a discharge toner tank (not shown). A mounting portion 6 is provided, and a door unit 2 door is opened and closed using fulcrum portions 7a and 7b when replenishing transfer paper, etc. Note that the manual feed tray 5 functions as a lid in the normal closed state, but when opened toward the front in the figure, it becomes an almost horizontal tray for manually feeding paper, and guides transfer paper that is manually fed from the outside (for details, see (described later).

In FIGS. 2(a) and 2(b), 8 is a recording section, and a transfer paper P is automatically fed to the recording section 8 through a conveyance path 10 from any one of automatic paper feeding sections 9A, 9B, and 9c. It looks like this. The automatic paper feed units 9A to 9C are designated by symbols A and 9C, respectively.
Although B and C will be omitted in the explanation, a plurality of untransferred transfer papers P
A plurality of paper feed cassettes 11 (transfer paper placement means) on which paper is placed with the paper surface facing up and down, and the uppermost transfer paper among the plurality of transfer papers P placed on these paper feed cassettes 11. A pinocqua pump roller 12 is attached to the paper feed cassette 11 to pick up the transfer paper P, and a plurality of paper feed rollers are housed in the door unit 7 to supply the transfer paper P picked up by the pickup roller 12 to the conveyance path 1o. 13. A pick-up roller 12 and a paper feeding roller 13 are provided corresponding to the plurality of paper feeding cassettes 11, and constitute a paper feeding means for feeding the transfer paper P of the corresponding paper feeding power cent.

Although the recording section 8 has a known configuration and will not be described in detail, the recording section 8 includes an image forming means 18 consisting of a photoreceptor drum 14 as an image carrier, a charger 15, an exposure optical system 16, and a developing unit 17, and an automatic image forming means 18. A transfer charger 19 (transfer means) that transfers the developed image of the image forming means 18 to the untransferred transfer paper P fed by the paper feed sections 9A to 9C, and a transfer charger 19 (transfer means) that transfers the developed image of the image forming means 18 to the untransferred transfer paper P fed by the paper feed sections 9A to 9C; A registration roller 21 that transports the paper P from a predetermined position to the transfer charger 19 and controls the transport timing of the transfer paper P, and heats the transfer paper P onto which the developed image has been transferred by the transfer charger 19 to fix the image. It also includes a fixing roller 22 that constantly rotates in the paper ejection direction, a transport heald 23 that transports the transfer paper P from the transfer charger 19 to the fixing roller 22, and the like. Here, the image forming means 18 includes a charger 1
The photoreceptor drum 14 charged by 5 is exposed to original reflected light containing image information by an exposure optical system 16 consisting of a light source, a first scanner 24, a second scanner 24, 25, etc. including a plurality of mirrors, and the photoreceptor drum 14 is After forming a latent image, the latent image is developed by the developing unit 17 to form a developed image on the photoreceptor drum 14. In addition, the registration roller 21
is adapted to rotate intermittently in synchronization with the rotation of the photosensitive drum 14 in order to control the conveyance timing of the transfer paper P.

As shown in FIG. 3, the conveyance path between the automatic paper feed units 9A to 9C and the registration rollers 21 is composed of the conveyance path 10 and the sandwich conveyance path 30.
0 is a path through which the transfer paper P is guided to the switch hack conveyance path 30 by the relay roller 29. This switch hack conveyance path 30 includes a switch hack mechanism 3.
1 is provided. Specifically, the switch hack mechanism 31 is formed of a flexible material (for example, mylar), and is provided with a guide plate 32 at the connecting portion of the re-convey path 10.30 to connect the transfer path 10 to the switch hack convey path 30. The backflow prevention member 33 is supported in a cantilever manner so as to allow only the conveyance of the transfer paper P, and the switch hack is installed to detect the displacement of the other end of the backflow prevention member 33 when the transfer paper P passes through. A relay sensor 34 that detects transfer paper P being carried into the transport path 30 and a switchback transport path 30
A switch hack sensor 35 is provided to detect the conveyance state of the transfer paper P, a friction pad 36 made of foamed polyurethane rubber, etc., and arranged approximately in the center of the switch hack conveyance path 30; A contact/separate roller 37 is made of rubber and rotates in forward and reverse directions at a position vertically facing the friction pad 36 with the switch hack conveyance path 30 interposed therebetween. A contact/separation solenoid mechanism 38 that can pinch and release the transfer paper P
(See FIG. 4), the leading edge of the transfer paper P, which is driven by a solenoid (not shown) or the like and oscillates, and which is sent out from the approach/separation roller 37 toward the registration roller 21 in the vicinity of the approach/separation roller 37, is connected to the guide plate 32. It is equipped with a clamper 39 that can be clamped between. This switch hack mechanism 31 transfers the transfer paper P fed from the automatic paper feeders 9A to 9C through the transport path 10 in the direction of arrow D1 (first transport direction) by normal rotation of the contact/separation roller 37 (in the figure). , clockwise rotation) into the switch bank conveyance path 30, while the reversal of the contact/separation roller 37 causes the paper to move backward in the direction of arrow D2 (second conveyance direction) while maintaining the orientation of the page in relation to the direction. It serves as means for reversing the conveyance direction (hereinafter also simply referred to as switch hack) and supplies the paper to the registration rollers 21 by adjusting the horizontal level between the transfer paper discharge position of the switch hack mechanism 31 and the transfer paper start position of the registration rollers 21. By making them substantially the same, the transfer paper P held by the registration rollers 21 is made substantially horizontal when the registration rollers 21 are stopped. As shown in the fourth section, the contact/separation solenoid mechanism 38 includes a solenoid 41 that moves the plunger 41a in the axial direction, and a rotating member 42 that rotates around a fulcrum portion 42a in response to the solenoid 41. The support member 43 is attached to the rotating member 42 and rotatably supports the approaching/separating roller 37, and a spring 44 is stretched between the frame 1a of the copying machine main body 1 and the rotating member 42. Also, as shown in Figure 5,
When the friction coefficient of the transfer paper P to be conveyed to the contact/separation roller 37 is μ1, the friction coefficient between the transfer papers P is μ1, and the friction coefficient between the transfer paper P clamped by the clamper 39 and the friction pad 36 is μ. , μ.

The materials of the friction pad 36 and the contact/separation roller 37 are selected so that 〉μ,〉μ2, and the other transfer paper P can be switch-packed while the transfer paper P is clamped by the clamper 39. In this example,
0.4〈μ,〈0.7 ,μ,〉1.6.1.0〈μt
<1.2.

Again, in FIG. 2, on the downstream side of the fixing roller 22,
A separating claw 51, a paper ejection sensor 52, and a paper ejection switching claw 53 are provided, and the separating claw 51 peels off the transfer paper P from the fixing roller 22 with the tip of the claw brought close to the fixing roller 22. The paper discharge sensor 52 detects the presence or absence of the transfer paper P and its passage on the exit side of the fixing roller 22, and sends paper discharge information to the controller. The paper ejection switching claw 53 closes one of a single-sided paper ejection passage 54 from the fixing roller 22 to the paper ejection tray 3 and a double-sided paper refeed passage 55 that descends from the fixing roller 22 and joins the conveyance path 10 again. At the same time, the other side is opened, and both roads 54 and 55 are switched. Also, a part of the duplex paper refeed path 55 is formed by the manual feed tray 5, and as shown by the imaginary line in FIG. 2, when the manual feed tray 5 is opened in the direction of arrow B in the figure, the duplex The lower part of the paper feed path 55 becomes a manual paper feed path. Specifically, as shown in FIG. 2.6, the double-sided paper refeed path 55 is formed by the manual feed tray 5 and a guide member 56 facing it, and the manual feed tray 5 is normally closed for conveyance. It functions as a manual feed tray only when it is in the open state. At the bottom of the double-sided paper refeed path 55, there is a gathering roller 57 such as a sponge roller, a pair of jogger fences 58A, 58B, and a tip stopper 59.
, a calling roller 60, a pickup roller 61, and a tray sensor 62 are installed, and the transfer paper P that enters the double-sided paper refeeding path 55 from the fixing roller 22 is passed through a shifting roller 57 that constantly rotates in the paper refeeding direction, and a jogger. Fence 58A, 58
B and the tip stopper 59, it is stacked in a fixed position, and is conveyed again by the calling roller 60 and the pickup roller 61, and the picking roller 60 and the pick knob roller 6 are stacked in place.
1, the paper is fed to the conveyance path 10 again. The tray sensor 62 detects the presence or absence of the transfer paper P stacked in front of the leading end stopper 59 and the paper width during double-sided copying, and detects the insertion of the transfer paper P into the manual tray 5 during single-sided copying. Further, an opening/closing sensor 63 is provided on the upper side of the duplex paper refeeding path 55, and the opening/closing sensor 63 detects opening/closing of the manual tray 5. And the manual feed tray 5 is
Based on a detection signal from the opening/closing sensor 63, the tray is locked from opening in the closed state during copying by a tray opening (not shown).

Here, FIG. 7 shows a control section that controls the operation of this device. In FIG. 7, 81 is a CPU consisting of a microcomputer, and the CPU 81 includes the aforementioned operation display unit 4, various sensors such as the aforementioned photosensors and switches, a DC power supply 82, and an AC driver that drives lamps and heaters. 83, a motor controller 84 for controlling the drive of the various rollers mentioned above, the various solenoids and actuators such as the solenoids mentioned above, ROM 85, non-volatile R
Connected to AM86. The CPU 81 controls the operation of the apparatus as described later by transmitting and receiving signals between the above-mentioned connections. Further, by appropriately executing the program according to the flowchart shown in FIG. 9 and 10 stored in the ROM 85, the CPU 81 turns on the DC power supply 82 to start one of the paper feeding means consisting of the plurality of pickup rollers 12, etc. It is used to select and operate the register roller 21 and the switch hack mechanism 31, and constitutes a control means. On the other hand, the copy start button 4a of the operation display unit 4 is operated by inputting a command signal to start the image forming operation by the operator's operation.
It is output to U81 and constitutes a start signal input means. Furthermore, the numeric keypad 4b and enter key 4C of the operation display unit 4 are used for paper feed cassettes IIA, 11B,
It inputs a command signal for selecting one of the paper feed cassettes 11C and outputs it to the control means, and constitutes a selection signal input means. For details, see paper cassettes 11A and I.
Each of IB and 11C is "1゛°'" on the numeric keypad 4b.
For example, when selecting the paper feed cassette 11A, if the "1" key of the numeric keypad 4b is pressed and then the "#" key of the enter key 4C is pressed, the paper feed cassette IIA This selection input operation may also be input by a dip inch (not shown) operation.

Furthermore, before inputting the command signal from the copy start button 4a, the CPU 81 inputs the command signals from the numeric keypad 4b and the enter key 4C, and then inputs the command signals from the numeric keypad 4b and the enter key 4C to input the pisokqua knob roller 12 and paper feeder corresponding to the paper feed cassette 11 selected. The paper roller 13 is selected and activated, and the switch hack mechanism 31 is activated to remove the pickup roller 12.
Then, the transfer paper P fed by the paper feed roller 13 is conveyed to the registration rollers 21 via the switch hack mechanism 31 and placed on standby.

Furthermore, the display section 4d of the display unit 4 constitutes a display means for displaying the size of the transfer paper P that has been conveyed to the registration rollers 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 paper feed cassettes 11A, IIB, and 11C, and the size of the transfer paper P of each paper feed cassette 11 is shown to the right of each number. is written, and the paper feed cassette 11 from which the transfer paper P waiting on the registration roller 21 comes is displayed by blinking the corresponding number (FIG. 8 shows the state where 1 is blinking). ). Also, the 8th
The frame line in the figure surrounds the number, paper size, etc. corresponding to the selected paper feed cassette 11, and displays the currently selected paper feed cassette 11.

Next, the flowchart in Figure 9.10 and the flowchart in Figures 11 to 1
The operation will be explained according to Figure 4. In addition, 3 in Figure 9.10
1 to 31B indicate each step 7 of the flowchart.

First, at 31 in Figure 9, D
When the C power source 82 is turned on, it is determined in S2 whether copying is in progress, that is, image formation is in progress, and if copying is in progress, the process advances to S3. In S3, when the last transfer sheet P in the series of copying operations is fed from the automatic sheet feeding section 9, the process advances to S4. S4
, execute the standby mode before starting the image forming operation of the subordinate,
In S5, control of various image forming operations to be described later after the start of image forming is executed. On the other hand, when copying is not in progress in S2,
Proceeding to S6, when the transfer paper P is detected by the switch hack sensor 35, that is, when it is detected that the transfer paper P is already waiting at the registration roller 21, S6 is executed.
If no detection is detected, the process proceeds to S4.

In the standby mode, at 87 in FIG.
b and enter key 4C to operate the paper feed solenoid, paper feed clutch, and drive motor of automatic paper feed section 9C corresponding to the selected paper feed force, so that paper is fed by automatic paper feed section 9C. (Figure 11(a))
). Next, in S8, the moving transfer paper P is detected by the relay sensor 3.
4, the process advances to S9. In S9, the contact/separation roller 37 is separated from the friction pad 36 (the 11th
(b)), when the transfer paper P is detected by the switch hack sensor 35 in the SIO, Sll! Go forward. Then,
At S12, the timer TI starts counting, and S12 starts counting the timer TI.
]2, when T1 becomes T1=t1, the process proceeds to 313.

However, tl is t1≧(the moving time of the transfer paper P between the nip of the switch hack sensor 35 and 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 in the normal direction (FIG. 11(c)). Next, in S14, when the trailing edge of the transfer paper P is detected by the intermediate sensor 34, the process proceeds to S15. Next, at 315, the contact/separate roller 37 is reversed (FIG. 11(a)), and at S16, the timer T2 starts counting, and when T2=t2 at S17, the process advances to S18. However, 12 is t2≧(relay sensor 3 of transfer paper P
4 and the registration roller 21 nip). Next, in S18, the drive motor of the approaching/separating roller 37 is stopped, the paper size of the transfer paper P placed on the paper feed force sensor (IIC) is displayed on the display section 4d of the operation display unit 4, and the standby mode is started. (Fig. 11(e)).

Next, various controls executed at 85 in FIG. 8 will be specifically explained.

Switchback First, copy start button 4a on operation display unit 4
When is turned on, copying starts and the transfer paper P placed on the paper feed cassette 11C is conveyed to the relay roller 29 by the paper feed roller 13C, as shown in FIGS. 12(a) and 12(b). . Furthermore, the transfer paper P that has been held by the registration rollers 21 and waiting is conveyed to the photosensitive drum 14 side at a predetermined timing by the rotation of the registration rollers 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). Transfer paper P
When the rear end passes the backflow prevention member 33, the contact/separation roller 3
7 is reversed as shown in FIG. 12(d), and the transfer paper P is switch hacked. Note that the paper feed roller 13C starts feeding the two sheets of transfer paper P after a predetermined time. Next, when the two-sheet transfer paper P is detected by the relay sensor 34, the contact/separation roller 37 separates from the friction pad 36, and the two-sheet transfer paper P is It continues to be conveyed by the relay roller 29, and its leading edge enters between the friction pad 36 and the uppermost transfer paper P. Next, as the registration roller 21 rotates, the rear end of the uppermost transfer sheet P comes out of the nip of the contact/separation roller 37, and the contact/separation roller 37 comes into contact with the friction pad 36, as shown in FIG. 12(f)! It rotates as shown, and the switch hacking operation of the two-sheet transfer paper P is started.

When a transfer paper P of a different size from the transfer paper P waiting in front of the registration roller 21 is selected, for example, a transfer paper P on the paper feed power center 11A, by an operation by a Coons or a switch operator, the registration When the transfer paper P, which was waiting in front of the roller 21, is separated from the registration roller 21 by the rotation of the contact/separation roller 37, and the rear end in the advancing direction is detected by the switch/hook sensor 35, the clamper 39 is activated and the contact is removed. The separation roller 37 is reversely rotated as shown in FIGS. 13(a), 13(b), and 13(c), and the transfer paper P is held by the clamper 39 after a predetermined time. Further, the paper feed roller 13A conveys the uppermost sheet of the transfer sheets P stacked on the paper feed cassette IIA to the relay roller 29. Next, when the leading edge of the uppermost transfer paper P is detected by the relay sensor 34, the contact/separation roller 37 separates from the friction pad 36 to prepare for insertion of the transfer paper P, as shown in FIG. 13(d). When the 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. 13(e).
When the rear end of the transfer paper P passes the backflow prevention member 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,
Its leading edge enters between the transfer paper P held by the clamper 39 and the contact/separation roller 37. Also, Fig. 13(f)
(g) As shown in (h), the paper feed roller 13A starts to convey the two sheets of transfer paper P after a predetermined time. here,
While the transfer paper P is clamped by the clamper 39, another transfer paper P can switch puncture on the transfer paper P because of the following.
As mentioned above, the relationship between the friction coefficients is μ, 〉
This is because μ, >μ2.

Coons 7 Registration Next, as shown in FIGS. 14(a) to 14(C), the transfer paper P is released from being held by the clamper 39, and the contact roller 3
7 rotates clockwise in the figure, the transfer paper P is separated from the clamper 39, and when the rear end of the transfer paper P is detected by the switchback sensor 35, the clamper 39 rotates downward and the approaching/separating roller 37 rotates counterclockwise,
The transfer paper P reaches the nip of the registration rollers 21 and stops.

On the other hand, after the recorded image is fixed by the fixing roller 22, the ejected transfer paper P passes through the ejection switching claw 53 into the double-sided paper refeed path 55.
By switching to the side, the paper is carried into the double-sided refeeding path 55, and its tip is brought to the tip stopper 59 by the shifting roller 57.
The materials are transported and stacked until they hit the . Note that if the duplex copy mode is not set, the transfer paper P is discharged to the paper discharge tray 3. Here, jogger fences 58A and 58B
When a plurality of transfer sheets P are stacked, the sides of the transfer sheets P are aligned in conjunction with the stacking operation one by one, and the horizontal registration is aligned with respect to the paper refeeding direction. When the double-sided copy mode starts, first, the tip stopper 59
The transfer paper P stacked at the paper refeeding position after copying on one side is completed is sent to the pick asopco 061 by the calling roller 6o, separated into minus sheets and transported to the switch hack transport path 30. Then, the conveyed transfer paper P is tightened by the switch hack mechanism 31 and reversed, so that the reverse side can be copied. The transfer paper P on which the reverse side copy has been completed is discharged to the paper discharge tray 3 by the paper discharge switching claw 53 which has been switched to the paper discharge tray 3 side, and the series of copying operations is completed. In this embodiment, the size of the transfer paper P to be stacked on both sides is A6. (Postcard) A4Y (Y
(transverse feed), LT (letter size)-y (however, the length is 216 mm or less), and transfer paper of longer length (e.g. B4, A4-T, A3, etc.) is It is best to make a double-sided copy.

When the manual feed tray 5 is opened horizontally, this is detected by the opening/closing sensor 63 and the manual feed mode is set, the paper ejection switching claw 53 is switched to the paper ejection tray 3 side, and at the same time, the selection of duplex mode is disabled. . Then, the shifting roller 57 moves upward, the jogger fences 58A and 58B move back to both sides, and the manually fed plural sheets of transfer paper P are moved to the leading edge stopper 59.
It is stuck at the position where the tip touches the. 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 paper P to align the sides of the transfer paper P. Note that the jogger fences 58A and 58B may be manually operated. The stacked transfer paper P is transferred to the pink-up roller 61 by the calling roller 60 as the leading end stopper 59 falls forward at the same time as paper feeding starts.
, separated, sent to relay rollers 29 , and conveyed to switch hack conveyance path 30 .

As mentioned above, in this embodiment, the main switch is ON.
Later, before the copy start button 4a of the operation display unit 4 is turned on, the transfer paper P in the paper feed cassette 11 selected by operating the numeric keypad 4b and enter key 4C is conveyed to the registration rollers 21 and kept on standby. Therefore, the time from turning on the copy start button 4a to starting the image forming operation after the main switch is turned on or after the image forming operation is completed can be shortened.

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

Furthermore, the operator who is the user selects the desired paper feed cassette 11 by operating the numeric keypad 4b and the enter key 4C.
Since the transfer paper P can be kept on standby in the registration roller 21, for example, the transfer paper P that is frequently used by the user can be kept on standby.
By selecting the paper feed cassette 11 in which the image forming apparatus is placed, copying productivity can be improved by shortening the time from turning on the copy start button 4a to starting the image forming operation.

[Effect] According to the present invention, before a command signal is input to the start signal input means, the transfer paper of the transfer paper mounting means selected by the selection signal input means is conveyed to the registration roller and kept on standby. Therefore, the time from when the start of the image forming operation is instructed until the start of the operation can be shortened.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIGS. 1 to 14 are diagrams showing an embodiment of the image forming apparatus according to the present invention, FIG. 1 is a perspective view of its external appearance, and FIG. 2(a)
(b) is its cross-sectional view, Figure 3 is an enlarged view of its main parts, and Figure 4 is its cross-sectional view.
The figure is a configuration diagram of the solenoid mechanism that moves the conveyance roller up and down, Figure 5 is an enlarged view of the main part to explain the switch hack mechanism, Figure 6 is a perspective view of a part of the manual feed tray,
FIG. 7 is a block diagram of the control unit, FIG. 8 is an enlarged view of the main part of the operation display unit, and FIGS. 9 and 10 are flowcharts of the program that makes the transfer paper standby.
Each figure is an explanatory diagram of its operation. 4a...--Copy start button (start signal input means), 4d...Display section (display means), 11A, IIB
, 11C...Paper feed cassette (transfer paper placement means)
, Fig. 4 14... Anger drum (image carrier), 18...
...image forming means, 19...transfer charger (transfer means), 21.
...Register roller, 31...Switch bank mechanism (transport direction reversal means), 81...CPU (control means), P...
・Transfer paper. Figure Figure Figure Figure Figure

Claims (2)

[Claims] (1) An image forming means that forms a latent image corresponding to the image of the original on an image carrier and develops the latent image to form an image; a plurality of transfer paper mounting means on which transfer paper is placed; A plurality of paper feeding means are provided corresponding to the transfer paper mounting means and feed the transfer paper of the corresponding transfer paper mounting means, and an image forming means develops images on the transfer paper fed by the paper feeding means. a transfer means for transferring the image;
Registration rollers that hold the transfer paper fed from the paper feeder in a predetermined position and convey it to the transferer at a predetermined timing; reversing the conveyance direction of feeding the transfer paper fed from the means in the first conveyance direction to the registration rollers in a second conveyance direction that moves backward while maintaining the orientation of the paper surface with respect to the first conveyance direction; a control means for selecting and operating one of the plurality of paper feeding means and controlling the operation of the registration rollers and the conveyance direction reversing means;
A start signal input means for inputting a command signal to start an image forming operation and outputting it to the control means, and a command signal for selecting one of the plurality of transfer paper mounting means for control. a selection signal input means for outputting the selection signal to the selection signal input means, and the control means inputs the command signal from the selection signal input means and outputs the selection signal input means to the selection signal input means before inputting the command signal from the start signal input means. The paper feeding means corresponding to the selected transfer paper mounting means is selected and activated, and the conveying direction reversing means is activated, so that the transfer paper fed by the paper feeding means is transferred to the register via the conveying direction reversing means. An image forming apparatus characterized by being conveyed to a roller and placed on standby. (2) A display means is provided for displaying the size of the transfer sheet that has been conveyed to the registration rollers and is waiting before the control means inputs the command signal from the start signal input means. The image forming apparatus described above.