JPH03174170A - Both-surface device - Google Patents

Abstract

PURPOSE:To improve operability by automatically eject a paper in a paper feeding path in a device to the outside of a machine when such an error that printing, etc., can not be continued occurs in a main body such as a printer. CONSTITUTION:The device is provided with a paper resupply path 56 for resupplying the paper to which recording is performed on one surface after it inverts the paper from a surface to a back surface, and a switch back system, etc., is used as a surface and back surface inverting means. In such a case, when such an error that printing can not be continued occurs in a paper feeding route 55 to a switch back part 14 or the paper resupply feeding route 56 to the part 14 in the middle of feeding the paper in the printer main body, a controller is informed of the error and does not execute a switch back action to the paper. A motor 18 continues to normally rotate to eject the paper to the outside of the machine from a switch back tray 21. Thus, a trouble that an operator takes out a remaining paper is avoided and an operation for recovery from the error is simplified.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a duplex device that enables duplex image formation in printers, copiers, and the like.

As a means of performing double-sided printing or double-sided copying with an image forming apparatus such as a printer or a copying machine, these image forming apparatuses accept paper that has been recorded on one side, turn it over and send it to the recording section of the image forming apparatus. Conventionally, a duplex device is attached to the main body of an image forming apparatus, and the duplex device refeeds the paper and discharges the paper on which duplex recording has been completed to the outside of the machine. As the front-back reversing means, a switch-back system using a switching pawl and a pair of transport rollers capable of forward and reverse rotation is simple in construction and is widely used.

By the way, if an error that makes it impossible to continue recording occurs in the main body of the image forming apparatus, such as a paper transport jam in the main body transport system, a fuser temperature error, a writing optical system error, etc. in the case of a printer, and the apparatus stops, With conventional equipment, if paper remains in the paper transport route from the paper receiving section to the reversing section of the duplex device and from the reversing section to the paper feed path of the main body of the device until it is restored and used again, it must be manually removed. It was necessary to do so, and there was a drawback that it was time-consuming.

Furthermore, even if an error occurs in the duplexer that makes continuous conveyance impossible, the paper remaining in the duplexer must be manually removed.

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of the conventional duplex device of an image forming apparatus, the present invention has been made to solve the problem when an error occurs in the main body of the image forming apparatus that makes it impossible to continue recording, or when continuous conveyance occurs in the duplex device. If an impossible error occurs, this duplex device ensures that there is no remaining paper in the duplex device, avoids the hassle of having to remove the remaining paper by the operator, and simplifies operations when recovering from an error. The challenge is to provide the following.

Steps for solving the problem In order to solve the above problem, the invention No. The present invention is characterized in that it has a control means for automatically ejecting the paper remaining in the double-sided device by the ejecting means when a signal indicating that an error has occurred in which recording cannot be continued is received.

Further, in a second aspect of the invention, the duplex device has a discharge means capable of discharging the paper stored in the device to the outside of the device, and when an error occurs in the duplex device that makes continuous conveyance impossible, The present invention is characterized by comprising a control means for controlling the paper remaining in the duplex device to be automatically ejected by the ejection means.

With the configurations of the first and second inventions described above, if an error occurs in the main body of an image forming apparatus such as a printer that makes it impossible to continue recording, or an error that makes continuous conveyance impossible occurs in a duplex device, respectively. In this case, the paper in the duplexer is automatically ejected out of the machine by its ejecting means, eliminating the need for human intervention.

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a diagram showing an overall schematic configuration of an example of a laser beam printer (hereinafter abbreviated as LBP) equipped with a duplex device to which the present invention is applied.

The duplex device has one duplex device transport section 13 and a switchback section 1.
4, the switch bar 14 consists of the LBP main body 1
The paper feed section 1 of 2 is provided at the upper right side in the figure, and the duplex device transport section 13 carries the LBP from the left surface where the discharge port of the LBP main body is located to the sui-sochiba-tsuku section 14.
It is provided on the left side and upper side of the key.

The recording paper 2 fed from the paper feeding device 1 in which the paper feeding cassette/slot is removably loaded in the LBP main body 12 passes through the 10 latitude, 1,000 inch color chain 51 □ 52, and then passes through one [? Enter the 2nd feed route 53 and move the registration roller 3 (main body conveyance roller (b)
)) The paper is fed to the photosensitive drum 4 at a timing determined by the timing. The photoreceptor 4 is rotationally driven in the direction of the arrow, and at this time, it is uniformly charged by the charging charger 5, and optical writing is performed on the photoreceptor 4 by the writing light from the laser writing optical system 6, and the electrostatic latent An image is formed. This latent image is developed by the developing device 7 to form a toner image, which is transferred onto the recording paper 2 by the transfer/separation charger 8. After the transfer, the recording paper is separated from the photoreceptor 4 and fixed on the main body conveyance route 53. The sheet is conveyed to the device 9, fixed by the fixing device 9, discharged from the LBP main body by the sheet discharge roller (c), and received by the duplex device conveyance section 13.

The receiving section of the duplex device is provided with a switching claw 17 that can switch the conveyance direction by a solenoid 24, and selects either the main body paper ejection route 54 or the paper conveyance route 55 to the switch bar 14. It is possible to switch between them. Paper transport route 55 of the duplex device transport section 13
A plurality of conveyance rollers (c'), (c'), and (d) are provided, and these conveyance rollers are driven by a stepping motor A15.

A conveyance route 55 for the duplex device extends straight through the switchback section 14 to above the switchback tray 21 outside the machine.

The switchback section 14 includes a switchback drive roller (
e), and a switching pawl 20 that is switched by a solenoid 25 is also provided. The switching claw 20 is located at a position where the paper can pass through the paper transport route 55 from left to right toward the switchback tray 21.
When the upper paper moves backward due to the reverse rotation of the switch bar/V-shaped drive roller (e), this is switched between the position where it is sent to the re-feed paper transport route 56 leading to the main body transport route 53. .

Further, the duplex device is provided with two paper conveyance standby positions and a temporary stop position. One of them is a first paper waiting position 22 for waiting so as not to feed the next paper when the switchback unit 14 is in operation (transporting paper), and the other is This is the second paper waiting position 23 when paper is re-fed from the section 14 to the main body transport route 53 via the re-fed paper transport route 56.

With the above configuration, when discharging paper for which double-sided printing has been completed in single-sided print mode or double-sided print mode, the switching claw 17 is connected to the main body paper discharging route 54 by the solenoid 24.
When refeeding paper that has already been printed on one side in duplex printing mode, switch the switching claw 17 to the paper transport route 55 side of the duplexer, and move the switching claw 20 to the solenoid 25 side.
First, from the paper conveyance route 55 to the switchback section 1
Switch back tray 2 to a position where it can be transported to 4.
After the paper is sent above 1 and the trailing edge comes off the switching claw 20,
The switching claw 20 is switched to the paper refeeding route 56 side, and the drive motor 18 is reversed to reverse the conveyance roller (e) to reverse the paper, so that the previous refeed paper conveyance route is carried out with the trailing edge first. The paper can be re-fed to the main body conveyance route 53 via 56.

FIG. 2 shows the duplex device transport section 13 and the switchback section 1.
4 is a block diagram of a duplexing device control device 26 for controlling the duplexing device 4. FIG. The duplex device control device 26 is connected via a serial line 28 to a printer main body control device 27 that controls the entire LBP.

The received signal RXD29 is command-analyzed by software processing by the CPU 31, and motor drivers A and B36.37
By driving the solenoid drivers A and B38 and 39, the conveying section 13 and switchback section 14 of the duplexing apparatus are operated.

Further, paper detection sensors A and B 16 and 19 provided in the transport section 13 and the switchback section 14, respectively, are trigger sources for timing the transport of paper.

Note that the signal line EERR40a is related to the first invention,
This is a signal line for notifying the duplex device control device 26 of an error in the printer main body, and the engine error signal 40 becomes High when an error occurs.

FIG. 3 is a timing chart of paper conveyance, motors A, B15, 18, and sensors A, B16, 19 of the above-mentioned LPB with duplex device. The horizontal axes (elapsed time) of these timing charts are common.

Lines (A), (B), (C), and (D) in the figure represent motors A, B15, 18, and sensor A, respectively.

B16 and B19 are shown as timing charts, and (E) is a timing chart showing the movement position of the leading edge of the paper based on the second paper standby position (23).

Main passage point (a) in the diagram of FIG. 3(E).

The intervals of (b), (c), (d), and (e) and the paper linear speed are set as shown in Table 1 below. Note that the basic specification is that the printing speed is 15 PPM (7 minutes per page). (
Imaging unit linear velocity near 2mm/see, paper feed interval: 63mm
, A4 paper feeding interval: 5 sec (min>) Table 1 As described above, the apparatus of this embodiment has a paper feeding route 51 (or 52) from the main paper feeding device 1 and a re-feeding route from the switchback section 14 of the duplex device. The printer has two paper feeding routes, a feeding paper transport route 56, and the printer main body control device 27 (FIG. 2) determines which one to feed paper from.When refeeding paper from the duplex device, The printer main body control device 27 sends a command to that effect to the control device 26 of the duplex device, and the control device 26 analyzes the command and operates the duplex device switchback section 14.

Furthermore, there are two routes for the paper discharge section.

One is a main body paper discharge route 54, and the other is a paper transport route 55 to the duplex device. In this case as well, the printer main body control device 27 determines which route to send the paper to, and if the paper is to be sent to the paper transport route 55, the duplex device control device 26 operates the duplex device 111 feeding section 13. .

In the example of the timing chart shown in Fig. 3, two
Paper is fed sheet by sheet from the main body's paper feeder L, the back side of each sheet is printed, sent to the duplex device conveyance route, switched back, fed again, front side printed, and ejected, which is repeated to print multiple duplex sheets. It is now ready to print. The drawing order in this case is as follows.

P, 2 (back of 1st sheet) → P, 4 (back of 2nd sheet) → P, 1 (
1st page) -P, 3 (2nd page) In Figure 3, the points marked with ○ are the P and E (paper ejection) commands, and the points marked with the mark are P, F (pa
per feed: paper feed) command is sent to the main body control device 27.
After receiving the command, the duplex device control device 26 analyzes the command and immediately executes the command. 4, 5 and 5 show the flow of the above command processing including processing related to the first invention, that is, processing related to control when an error (engine error) that makes it impossible to continue recording occurs in the main body of the image forming apparatus. It is shown in Figure 6.

The general flow of command processing is shown in Figure 4, and P, E
Details of the command, P, and F command processing flows are shown in FIGS. 5 and 6, respectively. With the P and E commands, the printed paper passes through the paper conveyance route 55°56 and moves to (a) in Figure 3.
> Return to position and wait for refeeding. Next, P.
The F command refeeds paper for printing on the opposite side.

However, Fig. 3 shows the situation under ideal control where the overload time spent waiting for P, E, P, F commands, command analysis, etc. is so small that it can be ignored, about 10 m5ec.

Note that when the paper that is being reversed and re-fed from the switchback unit 14 of the duplex device reaches the second paper standby position 23, the duplex device control device 26 issues a ready status using the transmission signal TXD30. The printer main body control 27 interprets this ready status and issues P and F commands to the duplex device control device 26.

The time tl in the timing chart of paper leading edge movement in FIG. The waiting position W22 indicates that the machine is in a "waiting" state. The previous paper is being re-fed by the P and F commands (paper transport route 56 is in use),
This is because motor B18 is rotating in reverse. Therefore, there is a "waiting" period until the execution of the previous P and F commands is completed and the motor B18 is no longer used. (Processing SIO and SLL in the flowchart in FIG. 5 are waiting for the motor B18 to be released.) Now, the paper is transferred to the paper transport route 55 in the duplexer or the re-feed paper transport route 56 of the switch section. If an error occurs in the printer that makes it impossible to continue printing during transportation, the engine error signal (40) becomes High as described above (decision S in Figure 5 (Part 2)).
1. Judgment S5 in the flowchart of FIG. 6), the control device 26 of the duplex device is notified of an error in the printer body. Upon receiving this signal, the duplex device control device 26 carries out the next remaining paper discharge process.

(1) For paper on the paper transport route 55, by rotating the motor B18 in the reverse direction (in the direction in which the paper is fed from left to right in FIG.
(Processes 82 to S in Figure 5 (Part 2)
4).

(2) For the paper being re-fed on the re-feed paper transport route 56, the switchback operation is not performed and the rotation of the motor B18 is rotated in the forward direction (the paper is fed from left to right in Figure 1). direction) and discharged from the machine from the sui-sochi back tray 21 (processes 86 to S9 in the flow of FIG. 6).

The CPU 31 of the duplex device control device 26 controls the reception number 4 RXD.
When reception of a command is detected by 29, a processing task corresponding to the command is activated in a command processing routine shown in FIG. Each task can be executed in parallel.

Processing related to the second invention, that is, control when an error occurs in the duplex device (paper transport route 55, 56) of the processing of the P, E (paper ejection) command and P, F, (paper feeding command) Flows including the above are shown in FIGS. 7 to 9.

FIG. 7 shows an overall general flow of command processing, and FIGS. 8 and 9 show detailed flows of P, E, command processing, and P, F, command processing.

These processes are executed by the CPU 31 (FIG. 2) in the interrupt routine when a reception interrupt occurs on the serial port (32).

The flow of paper ejection processing and paper feeding processing under normal conditions is as described above with reference to FIGS. 4 to 6.

Therefore, the process to be performed when an error occurs in the duplex apparatus that makes continuous conveyance impossible will be described below.

When an error is detected in the duplex device (discharged paper conveyance route 55, 56), the next paper discharge process is performed.

(1) If there is paper in the paper transport route 55, the first
As shown in the flowchart of paper ejection processing 1 shown in Figure 1, by rotating the motor A15 and motor B17 in the normal direction (in the direction in which the rollers are rotated so that the paper flows out of the machine from the switchback tray 21), the back tray 2
Discharge outside the machine from step 1.

(2) If there is paper on the paper transport route 56, the 12th
As shown in the flowchart of paper ejection processing 2 shown in the figure, by rotating the motor B18 in the normal direction, the paper is ejected from the switchback tray 21 to the outside of the machine.

Error detection is performed as follows (example of remaining paper error detection).

The remaining paper check process is carried out in accordance with the flow shown in Figure 1O.
This is carried out by the double-sided device control device 26 (FIG. 2) every 00 m east.

When P, E, command is received, flag FGSAONC
K, (P, E, 2.8 after command reception! E: flag for counting time) is set, and the counter CNTS-'
AONCK (P, E, after command reception 2.8!a: Counter for counting time) is made to count (process sl in Figure 8, judgment D3 in Figure 10, process S3
).

CNTSAONCK is 2 when it is counted 2800 times.
．． 8 seconds have passed, and at this point the leading edge of the normal paper has reached sensor A16, so the flag FGSAON is
(-t=7, a flag indicating that A16 should be ON) is set.

While FGSAON is set, the paper is
This means that the paper should not be detected by sensor A16 while FGSAON is cleared. Therefore, FGSAO
When N is cleared, the sensor A16 detects that the sensor A16 is ready, which means that there is paper when there should be no paper, that is, there is remaining paper, and the remaining paper ejection process 1 is performed. Fig. 10 Judgment Di, D2 and processing S2>.

When the paper is being transported from the paper transport route 55 to 56, the leading edge of the paper moves approximately 0.1 from the timing when it reaches the e-roller.
It is detected by sensor B18 after 5x. Taking into account the delay margin due to conveyance slips, etc., after 0.2 formulas, sensor B
18 is assumed to detect the leading edge of the paper, and the flag FGS is set.
BON (a flag indicating a state in which the sensor B18 should be ON) is set (FIG. 8 (Part 2) Process S4).

While FGSBON is set, paper is placed in sensor B.
This means that the paper should not have been detected by sensor B18 while FGSBON is cleared. Therefore, FGSA
As in the case of ON, if paper is detected by the sensor B18 while FGSBON is cleared, it is determined that there is a remaining paper in the paper transport route 56, and the remaining paper ejection process 2 is performed.
(Figure 10 Judgment D4. D5 and processing S5).

In the present invention, there are a maximum of three sheets of paper in all the paths of the image forming apparatus main body transport system 53, the duplex device transport system 55, and the duplex device switchback system 56, as shown in the timing chart of FIG. Since the paper is transported in a timing sequence, if there is any remaining paper, the state of transport of the remaining paper is not guaranteed, and a jam occurs on the paper transport route 56 (paper refeeding route), making continuous printing impossible. Therefore, it is necessary to remove the remaining paper.

In the above description of the embodiment, in order to make it easier to understand, the flow in which only one of the processes of the ↓ invention and the process of the second invention is performed in the paper ejection and paper feed command processing process was separately explained. It is of course possible to detect both an engine error and an error within the duplexer in one flow and perform processing for both, and in fact, it is appropriate to do so.

As mentioned above, if an error occurs in the main body of the printer that makes it impossible to continue printing, or if an error occurs in the duplexer that prevents continuous conveyance, the paper in the paper transport path in the duplexer will Since the paper is automatically ejected to the outside of the machine, there is no need for the operator to manually eject the remaining paper to the outside of the machine when an error is recovered, which simplifies the operation and improves operability.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the general configuration of an embodiment of a laser printer equipped with a duplex device to which the present invention is applied, centering on a paper conveyance path, and FIG. 2 is a block diagram of a control device of the duplex device. FIG. 3 is a timing chart of the paper conveyance, drive motor, and paper sensor of the duplexing device, FIG. 4 is an example of a flowchart of command processing including control according to the first invention of the duplexing device control device, and FIG. FIG. 6 is a flowchart showing a detailed flow of paper command processing; FIG. 7 is an example of a flowchart of command processing including control according to the second invention; FIG. FIG. 9 is a flowchart showing the detailed flow of the paper ejection command processing, FIG. 9 is a flowchart showing the detailed flow of the paper feed command processing, FIG. 10 is a flowchart of the remaining paper check processing, and FIGS. 11 and 12 are flowcharts of the paper ejection process. ■...Paper feeding device, 2...Paper, 4...Photoreceptor, 13...Double-sided device transport section, 14...Double-sided device switchback section, 15...Motor, 16.19. ...Sensor, 17.20...Switching pawl, 18...Motor capable of forward and reverse rotation, 20.23...Standby position, 21...Switch bar/tray, 24.25...Solenoid, 51. 52...Paper feed conveyance route, 53...Main body conveyance route, 54...Main body paper discharge route, 55...Double-sided device paper conveyance route, 56...Refeed paper conveyance route

Claims (2)

[Claims] (1) In a duplex device of an image forming apparatus that has a refeed path for flipping and refeeding sheets that have been recorded on one side, the duplex device may eject the paper in the device to the outside of the device. If a signal indicating that an error that prevents continuation of recording has occurred within the image forming apparatus main body is received, the paper remaining in the duplex device is controlled to be automatically ejected by the ejecting means. A double-sided device characterized by having a control means. (2) In a duplex device of an image forming apparatus that has a refeed path for flipping and refeeding single-sided printed paper, the duplex device may eject the paper in the device to the outside of the device. and a control means for controlling the sheet remaining in the duplex device to be automatically ejected by the ejection means when an error that makes continuous conveyance impossible occurs in the duplex device. A double-sided device characterized by: