JP2702533B2 - Double-sided device - Google Patents

Description

The present invention relates to a double-sided device, and more particularly to a printer,
The present invention relates to a double-sided device applicable as a part of a recording device such as a copying machine.

[Conventional technology]

Image transfer is performed on one side of the paper by passing the paper sent from the paper feeding unit to the one side of the paper, and then reversed by switchback means as reversing means provided in the middle of the loop-shaped transport path, and then again, the paper is transferred. A double-sided device that transfers an image to the back surface of the one side by passing through one side, and guides the back surface down or up to the paper output tray, wherein the switchback unit mainly includes a switchback roller that can rotate forward and reverse. A double-sided device for controlling the switching of the switchback roller holding the paper from a normal rotation for feeding the paper to a reverse rotation for feeding back the paper at the time of switchback is applied to a printer or the like.

For example, referring to FIG. 8, an image is transferred to one side A of the paper in the paper feed unit 1 by a transfer unit 2 constituting a part of the printer in FIG. Then, it is reversed by the switchback roller 3 to reach the transfer section 2 again.
Is transferred to the image, and thus the image is formed on both sides.

The paper on which images are formed on both sides is discharged to the discharge tray 4 with one side A facing down, that is, in a so-called face-up state with the transfer surface facing up. Alternatively, when the paper is discharged with the one side A facing up, that is, in the so-called face-down state with the transfer surface of the latter facing down, the path is switched at the branch portion 5 in front of the paper discharge tray 4 to be further reversed. The paper is discharged to the paper discharge tray 6. Further, as an improved technique, an image is transferred to one side of the paper by passing a paper sent from a paper feeding section through a transfer section, and then the paper is switched back by switchback means provided in the middle of the loop-shaped transport path. Then, there is a double-sided device capable of transferring an image to the back surface of one side again by passing the paper through the transfer section, and discharging the paper to a paper discharge tray provided on the paper feeding direction side of the switchback means. In this double-sided device, the configuration is simplified by placing the switchback means and the paper discharge tray on the same transport path. Further, there is a paper discharge tray which also has the function of a manual feed tray.

[Problems to be solved by the invention]

In a conventional double-sided device, there is a device in which the paper discharge tray also has the function of a manual feed tray, but the specific contents are not clear. SUMMARY OF THE INVENTION An object of the present invention is to provide a double-sided device capable of appropriately using a discharge tray as a manual feed tray.

[Means for solving the problem]

In order to achieve the above object, in the double-sided device of the present invention, the switchback means is constituted by a pair of switchback rollers capable of rotating forward and backward, and a paper detecting means for detecting the presence or absence of paper in the paper discharge tray; Control means for controlling the rotation direction of the switchback roller pair according to the mode is provided, mode switching information by the control means,
The rotation direction and rotation start timing of the switchback roller are controlled based on the paper detection information by the paper detection means, so that the paper discharge tray can also serve as a manual feed tray.

[Action]

In the present invention, conditions for the discharge tray to function as a manual feed tray are determined.

〔Example〕

In FIG. 1, reference numeral 100 denotes a printer main body. In the printer main body 100, an entrance sensor 17, a switching claw 18, a switchback roller pair 19, a switching claw 20, a conveyance sensor 21, and the like are main components. Such a double-sided device is configured.

In FIG. 1, reference numeral 10 denotes a first cassette, in which recording papers are stacked and housed, and mounted in a substantially horizontal position as shown in FIG.

A pickup roller 11 is located above the left end of the first cassette 10, and is in pressure contact with the uppermost sheet in the cassette with an appropriate pressure. Therefore, when the pickup roller 11 rotates during printing, several sheets of paper in the cassette are fed out in the direction of the dashed arrow, and are fed to the press-contact portion between the paper feed roller 12 and the reverse roller 13 provided on the downstream side of the path. Then, only one sheet is separated by utilizing the difference in friction coefficient between these two rollers and the sheet, and the separated one sheet is sent to the registration roller pair 14 where the leading end reaches the roller pair. The feed is temporarily stopped and the apparatus enters a standby state.

On the transport path shown by the broken line, downstream of the registration roller pair 14, reference numeral 15 denotes a photosensitive member, and a toner image is carried on the photosensitive member by an image forming means (not shown). Is rotated.

Therefore, if the registration roller pair 14 is started to be driven in synchronization with the arrival of the toner image, the toner image is first transferred onto one side A of the paper by the action of a transfer charger or the like at the transfer portion on the top of the photoreceptor. If the image is further fed and passes through the fixing roller pair 16, the image is fixed.

When the leading end of the fixed paper is detected by the entrance sensor 17, the switching claw 18 moves to the position of the imaginary line, and switches the paper path upward. As a result, the paper is directed to the switchback roller pair 19 corresponding to the position above the first cassette 10.

A discharge tray 23 according to the present invention is provided near the switchback roller pair 19 and on the side of the paper feeding direction.

Further, a path switching claw 20 is provided immediately upstream of the switchback roller pair 19, and a transport sensor 21 is further provided upstream of the switching claw 20.

Here, the mode in which the paper conveyed to the switchback roller pair 19 is rotated forward in the paper feeding direction for a predetermined time, then reversely rotated in the paper feeding direction for a predetermined time, and the paper is again fed to the transfer unit is referred to as a forward / reverse rotation mode. Called.

This forward / reverse rotation mode is applied when the paper is moved backward to form an image on the back surface B of the paper on which the image is formed on one side A. On the other hand, there is a normal rotation mode. This forward rotation mode is a mode in which the paper is sent to the paper output tray 23. In this mode, the switchback roller pair 19
Rotate forward in the paper feed direction until the paper is completely fed into 23.

Now, since the single side A is formed on the paper, the switchback roller pair 19 is controlled according to the forward / reverse rotation mode.

When the leading edge of the paper is detected by the transport sensor 21, the switching claw 20 is switched to the position shown by the imaginary line, and the paper is guided to the switchback roller pair 19. The switchback roller pair 19 first rotates forward to feed the paper in the feed direction. And
Immediately after the trailing edge of the paper passes the switching claw 20, the rotation of the switchback roller pair 19 is switched to reverse rotation. At this switching timing, a predetermined time is counted from the detection of the trailing edge of the paper by the transport sensor 21 to make a determination.

As a result, the portion that was the rear end until now becomes the front end and reversely moves, moves forward diagonally to the left by the switching claw 20, and is again conveyed toward the registration roller pair 14, and waits for the registration roller pair 14. Becomes

At this time, one side A of the paper (the surface on which an image has been formed earlier) is facing upward, and the back surface of this one side A is in a relationship capable of facing the photoconductor 15 and is ready for image formation. When the time comes, this paper is sent out from the registration roller pair 14 in synchronization with the toner image on the photoconductor, and an image is formed on the back surface in the same process as described above. The paper on which images are formed on both sides in this way passes through the fixing roller pair 16 and then returns to the entrance sensor.
Detected at 17.

In this case, if the mode specified in advance is the face-down mode in which the second transfer surface is accommodated with the transfer surface facing down, the switching claw is used.
Reference numeral 18 is switched to the position of the imaginary line, and the paper is discharged to the face-down discharge tray 22 provided to the left of the claw.

On the other hand, if the mode designated in advance is the face-up mode in which the second transfer surface is accommodated with the transfer surface facing upward, the switchback roller pair 19 is in the forward rotation mode, and the switching claw 18 is switched to the solid line position and Proceed along the path and transport sensor 21
Is detected, the switching claw 20 is switched to the position of the imaginary line, and is sent to the face-up discharge tray 23 provided outside the switchback roller pair 19.

In this case, since the rotation of the switchback roller pair 19 is in the normal rotation mode, the normal rotation drive is continued until the paper is completely discharged to the face-up discharge tray 23 without being reversed halfway.

In addition, in addition to the first cassette 10, the second cassette
Although there are 24 paper feeders, the configuration related to paper feeding is similar to the configuration related to the first cassette 10, and therefore the description is omitted.

Next, the above process will be described with reference to FIGS.

In FIG. 2, the printer system 30 surrounded by a broken line
Corresponds to the control system of the printer main body 100 shown in FIG. 1 and is connected to the host computer 31 via a data line, and outputs a hard copy based on the transfer of print data.

The printer system 30 includes a controller 32, a printer control unit 33 including a CPU (central processing unit), a double-sided device control unit 340 including another CPU, a motor 35, a paper presence sensor 36, and the like.

The controller 32 converts the print data sent from the host computer 31 into an image signal for a printer, and sends it to the printer control unit 33. At the same time, a print start command, a paper feed position selection command, a paper discharge position selection command, and the like are sent to the printer control unit 33 via the serial communication a. The duplex device control unit 340 receives a printer status signal from the printer control unit 33.

Then, the double-sided device control unit 340 controls the motor 35 for driving the switchback roller pair 19 by transmitting and receiving the serial communication b and a signal from the paper presence sensor 36 described later.

The serial communication b includes a command for setting the operation mode (forward / reverse rotation mode, forward rotation mode) of the motor 35 of the switchback roller pair 19, a paper feed command, a stop command, a restart command, and the like.

The switchback roller pairs 19 are all operated according to the forward / reverse rotation mode except when the paper is sent to the paper discharge tray 23.

This will be described with reference to the flowchart of FIG. 3. In step 1, it is determined whether or not the duplexer reversing unit, that is, the discharge tray 23 is selected as the discharge position.

If the determination is affirmative, the process proceeds to step and the normal rotation mode is set. If the determination is negative, the process proceeds to step and the normal / reverse mode is set.

Next, a description will be given of a case where an abnormality such as a jam occurs outside the duplex apparatus 34 during continuous duplex printing.

In this case, a measure is taken to automatically stop the entire printer system upon receiving a jam detection signal as an abnormal situation. In addition to the paper that caused the jam, other papers must be manually removed by opening the lid during the jam processing. This is because, during continuous double-sided printing, up to three to four sheets of paper are being conveyed in the printer main body 100. Cannot proceed to the process section anymore because it can be used earlier, and because the printing order and the discharging order are out of order, it is impossible to print the back side of these remaining sheets as they are even after the jam processing.

Therefore, in this example, when a jam occurs in the fixing unit or the like during continuous printing on both sides, the forced paper ejection command from the printer control unit 33 is received by the duplex device control unit 340, so that the paper feeding in the duplex device 34 is stopped. Control is performed such that the sheet is sent out of the apparatus via the switchback roller pair 19 without stopping.

 This process will be described with reference to the flowchart of FIG.

In FIG. 4, when it is determined that printing is being performed in the step, and when the occurrence of a jam is determined in the step, it is determined in the step whether or not any transportable paper remains in the duplex apparatus 34. You.

As the determination material, a print mode, the number of prints, sensor information, and the like can be used.

If the presence of residual paper is determined in the step, the serial communication b is sent from the printer control unit 33 to the duplex device control unit 340 in the step, the normal rotation mode is set, and the residual paper is quickly sent out to the output tray 23. It is. The double-sided device control unit 340 shown in FIG. 2 performs such control.

As a result, the user is free from the trouble of removing paper in the duplex apparatus 34 by opening the lid of the apparatus when a jam occurs.

Next, the manual feed function of the switchback roller pair 19 and the paper output tray 23 provided near the switchback roller pair 19 will be described.

In this example, the switchback roller pair 19 and the paper discharge tray 23 can be used as manual feeding means.

In order to fulfill this function, as shown in FIGS. 6 and 7, a paper presence detection sensor 43 comprising a combination of a detection filler 41 and a photo interrupter 42 is provided on the discharge tray 23 side of the switchback roller pair 19. I have.

The photo interrupter 42 is fixed to the frame 40. The detection filler 41 has an intermediate portion pivotally attached to the frame 40 and is rotatable. In a balanced state by its own weight, the upper end of the detection filler overlaps the photointerrupter 42 and the lower end thereof as shown by a virtual line in FIG. Is fitted into the concave portion 44 of the paper discharge tray 23. In this state, there is no paper on the discharge tray 23, and the output of the paper detection sensor 42 is output to the duplex device 34.

On the other hand, as shown in FIG.
When the is pressed, the leading end of the paper 50 pushes the lower part of the detection filler, whereby the upper part of the detection filler is disengaged from the photointerrupter 42, and the presence of the paper is detected.

Hereinafter, the manual feed process will be described with reference to FIG.

It is determined in step whether or not the mode is the manual feed mode. In the manual feed mode, for example, a command by operating a changeover switch is set. If the manual feed mode has been set, the process proceeds to step S, where it is determined whether or not there is any paper in the paper output tray 23, or strictly, whether or not the leading edge of the paper has reached the nip portion of the switchback roller pair 19.

If there is paper, it is determined in step whether or not there is a paper feed command. Here, if the printer control unit 33 that has received the print start command through the serial communication a issues a paper feed command to the duplex device 34 through the serial communication b, it is determined that there is a paper feed command, and the process proceeds to step S22. The reversal of 19 is started, the paper 50 is pulled in, and the registration roller pair 14
Is started toward.

When the leading edge of the paper reaches the pair of registration rollers 14, the printer control unit 33 sends a stopper command to the duplex unit control unit 340 (step), whereby the switchback roller pair 19 is sent.
Is stopped (step). And the photoconductor 15
When there is an instruction to restart the registration roller pair 14 in synchronization with the arrival of the upper toner image, the process proceeds from step to step.

In the step, the output of the paper presence sensor 43 causes the trailing edge of the paper to pass through the sensor to determine whether or not a certain period of time has elapsed since the paper output tray 23 became empty. When the trailing edge of the paper completely passes through the switchback roller pair 19 with the passage of time, the process proceeds to the next step. In the step, the rotation of the switchback roller pair 19 is stopped to wait for the next paper setting.

The double-sided device control unit 340 shown in FIG. 2 performs such control.

According to this example, since the switchback unit is a manual feed unit, there is no need to provide a new manual feed device, and the configuration can be simplified.

In the case where the paper is sent out to the paper discharge tray 23, the seventh
As shown in the figure, the detection filler 41 is rotated in the counterclockwise direction by the paper to allow the paper to pass, so that the problem of the discharge stackability does not occur.

〔The invention's effect〕

According to the present invention, by clarifying the conditions under which the paper discharge tray also serves as the manual feed tray function, the paper discharge tray can be appropriately used as the manual feed tray.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a printer main body suitable for carrying out the present invention,
FIG. 2 is a block diagram of the printer system, FIGS. 3 to 5 are flowcharts illustrating an embodiment of the present invention,
6 and 7 are explanatory diagrams of a peripheral portion of a paper discharge tray according to the present invention, and FIG. 8 is an explanatory diagram of a conventional technique. 23: paper ejection tray, 340: double-sided device control unit.

Claims (1)

(57) [Claims] An image is transferred onto one side of a sheet of paper fed from a paper feeding section through a transfer section, and then the paper is switched back by a switchback means provided in the middle of a loop-shaped conveyance path, and then again. A double-sided device capable of transferring an image to the back surface of the one side by passing the paper through the transfer portion and discharging the paper to a paper discharge tray provided on the paper feeding direction side of the switchback means; Is constituted by a pair of switchback rollers that can be rotated forward and backward, and the paper discharge tray is provided with paper detection means for detecting the presence or absence of paper and control means for controlling the rotation direction of the switchback roller pair according to the mode. The rotation direction of the switchback roller is changed based on the mode switching information by the control means and the paper detection information by the paper detection means. It is controlled to interrupt direction, double-side unit, wherein the discharge tray has to be also serves as a manual feed tray.