JPH0664817A - Automatic reversal device for digital copying machine - Google Patents

Abstract

(57) [Summary] [Purpose] In a digital copier with an automatic reversing function, switching from reverse ejection to normal ejection is performed in the shortest time. [Structure] A means for storing the discharged surface of the preceding paper is provided. It has means for detecting the paper size. A means for storing the paper size of the preceding paper is provided. When the preceding paper is reverse discharge and the following paper is normal discharge, depending on the stored paper size of the preceding paper,
Make the trailing paper stand by at the registration section.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic reversing device for a digital copying machine.

[0002]

2. Description of the Related Art In a copying machine having an automatic reversing function, whether to invert / non-reverse ejection is decided according to an operation mode. The decision is made by an automatic document feeder (ADF) with a document reversing function (RADF). , Or how the document feed order is designed, but in general,
It is necessary to discharge the paper so that the order of the discharged paper is the same as the order of the originals.

A laser beam printer (LBP)
Since it is general that the ejected sheets are stacked according to the order in which they are first output, it is necessary to eject the paper on the back side. However, in practice, most printers switch mechanically because there is no need for the automatic reversal function.

On the other hand, in digital copying machines, a type in which a printer is integrally combined has appeared, and in this case, the output of the copying machine is generally surface discharge, and when switching to the printer function, it is common. An automatic reversing paper ejection device is provided so that different back paper ejections can be selected.

However, in the conventional digital copying machine,
If you switch from copy mode to printer mode, a series of operations in copy mode will cause a break (for example,
Since the printer mode is entered at the time of completion of paper discharge), the switching time is long and the productivity is extremely reduced.

More specifically, FIG. 4 shows an example of a paper feeding / conveying mechanism of a general digital copying machine with an automatic reversing function.
1 is a transfer paper cassette, 2 is a paper feed roller, 3 is a registration roller, 4 is a photoconductor, 5 is an exposure point by the polygon writing unit 6, 7 is a fixing roller, 8 is a reversing switching claw, 9 is a reversing roller, 10 Is a reverse stocker, 11 is a discharge roller, 12 is a discharge tray, and 13 is a manual paper feed roller.
Further, each of the registration roller 3, the fixing roller 7, and the paper discharge roller 11 are provided with a registration sensor, a fixing sensor, and a paper discharge sensor for controlling the paper conveyance.

First, one sheet of transfer paper is fed by rotating the paper feed roller 2 and the arrival at the registration roller 3 is detected by a registration sensor, whereupon the registration roller 3 is stopped and the paper is awaited. Let Next, when an image signal request is issued, a signal for forming an image is input at the exposure point 5, and only the difference between the distance from the exposure point to the transfer point and the distance from the registration roller 3 to the transfer point causes the registration roller 3 to move. Wait for the paper to wait and then restart the registration roller. As a result, the leading edge of the paper and the leading edge of the image are matched. Then, the timing of paper feeding is possible may vary in layout such as paper size machine, unless spaced a minimum of several tens of mm because it can not jam detection, this interval sheet interval L ₁ and (mm) Call.

Now, in the automatic reversing machine, when the paper is normally discharged, the paper P is conveyed as it is, as shown in FIG.

On the other hand, in the case of reverse ejection, first, as shown in FIG. 6A, the conveyance path of the paper P is changed by the reversal switching claw 8 and the paper P is guided to the reversal stocker 10. At this time, the paper is conveyed by the fixing roller 7. As shown in FIG. 6B, the fixing roller 7 is controlled so that the reversing roller 9 conveys the paper immediately before the paper P comes out.
Next, when the paper P has completely passed through the fixing roller 7, as shown in FIG. 6C, the reversing roller 9 is rotated in the reverse direction, and the reversing switching claw 8 moves the paper P toward the paper discharging roller 11. Guide Subsequently, as shown in (d) of FIG. 6, after the leading edge of the preceding paper P reaches the paper discharge roller 11, the paper discharge roller 11 carries the preceding paper P. It is possible to cancel the above, and it is possible to shift to the reverse sheet ejection control of the next sheet P ′.

Here, considering the sheet interval L _{2 in the} case of continuous reversal, the distance becomes necessary for the steps (B) to (D) of FIG. That is, the time until the trailing edge of the preceding paper P passes the fixing roller 7 and the reversing roller 9 conveys the preceding paper, and the rotation direction is switched to reach the leading end of the preceding paper to the discharge roller 11 x paper conveyance speed. = L ₂ .

Generally, in order to design the mechanical mechanism so that the above-mentioned L ₁ and L ₂ are equal to each other, continuous normal paper discharge,
When the sheet is reversed and discharged, the sheet interval should be controlled to be constant. Therefore, conventionally, switching to the reverse discharge is performed after all the normal discharge is completed. The reverse is also true.

[0012]

However, when the digital copying machine is operated in combination with the printer function,
In the conventional method, since wasteful time is generated every time the paper discharge is switched, the productivity is lowered.

When the operation of the reversing machine is carefully considered, when the preceding paper and the paper waiting in the registration section this time (following paper) are the same in the paper discharge method, the normal paper interval L ₁ = L ₂ is sufficient. That was mentioned above. In general, this sheet interval is performed at the sheet feeding control stage before reaching the registration roller, and thus the ordinary registration process may be performed by the above-described sheet leading edge alignment process. Also, no special processing is required when switching from normal paper ejection to reverse paper ejection. The problem is when switching from reverse paper ejection to normal paper ejection. In this case, the minimum paper interval L
_{When the} paper is conveyed at ₁ = L ₂ , the trailing paper enters the reversing machine during the reversing process of the preceding paper, which causes a jam.

Therefore, in the present invention, by controlling the waiting time in the resist portion, it is possible to minimize the wasteful time for switching and to eliminate the jam of the preceding paper and the succeeding paper. It is what

[0015]

In order to solve the above-mentioned problems, the present invention provides an automatic reversing device for a digital copying machine in which printed paper can be selectively discharged on the front surface and the back surface. A means for storing the front side of the paper,
A means for detecting the paper size in advance and a means for storing the paper size of the previous sheet are provided, and when the previous sheet is the reverse ejection paper and the next is the non-reversal ejection paper sheet, the stored previous paper sheet According to the size, the resist unit holds the next paper to be discharged for a required time.

Further, means for measuring the elapsed time after the trailing edge of the paper passes through the resist portion is provided, and the paper to be discharged next is
It is preferable that the registration unit has a function of causing the registration unit to stand by for a difference between the elapsed time of the previous sheet of paper passing through the registration unit and the stored paper size.

Further, a means for measuring the time taken for the paper to pass through the resist portion and a means for holding the measured time are provided, and when the paper whose length cannot be detected reaches the resist portion in advance, It is preferable to have a function of controlling the waiting time at the registration unit according to the discharge surface, the registration unit passage time of the paper, and the passage elapsed time.

[0018]

[Function] When the preceding paper is reversed and the following paper is normally discharged,
The trailing sheet is made to wait in the registration unit for the required time according to the stored sheet size of the preceding sheet.

Further, if the trailing sheet arrives late at the resist portion, the trailing sheet can be made to stand by at the resist portion by the difference between the resist portion passing time of the preceding paper and the stored paper size. Become.

Further, when a paper whose length cannot be detected reaches the registration section, such as manual feeding, the trailing sheet is registered in the registration section according to the discharge surface of the preceding sheet, the registration section passage time of the paper, and the passage elapsed time. Can be put on standby.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention. In a configuration similar to that of the digital copying machine shown in FIGS. 4 to 7, means for storing the surface of the paper discharged one sheet before, and paper size in advance. And a means for storing the paper size of the previous sheet, and when the first previous sheet is the reverse discharge sheet and the second is the non-reverse sheet discharge sheet, In addition, the registration unit has a function of causing the registration unit to wait the next sheet to be discharged for the minimum sheet interval L ₃ .

More specifically, the sheet interval L ₂ is determined from (B) to (D) of FIG. 6, but it is most important for the trailing sheet to reach the reversing machine without causing a jam after the reverse sheet ejection. As for the early timing, as shown in FIG. 7B, the leading edge of the trailing sheet P ′ reaches the fixing roller 7 immediately before or after the trailing edge of the preceding sheet P passes through the discharge roller 11. It's timing. On the other hand, the difference L ₃ −L between FIG. 6D and FIG. 7B
_It can be seen that ₂ is almost the length of the paper. Of course, there are some differences depending on the mechanical layout, but since these errors are not directly related to the description, it is assumed that L ₃ −L ₂ = paper length as a representative value.

Therefore, if the paper size is known in advance, as shown in the flow chart of FIG.
_{In 3} you can switch from reverse ejection to normal ejection. In addition,
The size of the paper can generally be known by cassette size detection.

Next, FIG. 2 shows another embodiment of the present invention. In the same configuration as the above embodiment, means for measuring the elapsed time after the trailing edge of the paper passes through the resist portion is provided. It is provided with a function of making the sheet to be ejected next time stand by at the registration section by the difference between the elapsed time when the previous sheet passes the registration section and the stored sheet size.

In this embodiment, when the trailing sheet arrives late at the resist portion, it is noted that the waiting time at the resist portion may be short as much as the preceding paper has passed. The shortest waiting time is always realized by measuring the elapsed time of and waiting for this difference.

FIG. 3 shows still another embodiment of the present invention. In the same configuration as that of the embodiment of FIG. 2, means for measuring the time taken for the paper to pass through the resist portion and the measured time. When the paper whose length cannot be detected reaches the registration part in advance, the waiting time at the registration part is controlled by the discharge surface of the previous paper, the registration part passage time of the above paper, and the passage elapsed time. It has the function to do.

In the case of such an embodiment, when the length of the paper is unknown in advance such as manual feeding, the time for passing through the resist portion is measured, and this time is used for the following timing calculation to switch. Can be done in the shortest time.

The present invention is not limited to the above-mentioned embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

[0029]

As described above, according to the automatic reversing device of the digital copying machine of the present invention, when the preceding paper is reversed and the trailing paper is normally discharged, the stored paper size of the preceding paper is stored. In accordance with the above, the function to hold the trailing paper in the registration section for the required time is provided, so the time for switching can be minimized, productivity can be improved, and the occurrence of jams can be eliminated. If the trailing sheet arrives late at the registration section, the trailing sheet waits at the registration section for the difference between the registration sheet passage elapsed time of the preceding sheet and the stored paper size to achieve the shortest wait. In addition, when the length of the paper is not known, such as manual paper feeding, the time required to pass through the resist section can be measured, and the trailing paper can be put on standby based on this time. Demonstrate.

[Brief description of drawings]

FIG. 1 is a flowchart showing an embodiment of an automatic reversing device for a digital copying machine according to the present invention.

FIG. 2 is a flowchart showing another embodiment of the present invention.

FIG. 3 is a flowchart showing still another embodiment of the present invention.

FIG. 4 is a schematic view showing an example of a paper feed / conveyance mechanism of a digital copying machine with an automatic reversing function.

FIG. 5 is a schematic diagram showing a normal paper discharge state.

FIG. 6 is a view showing a reversed sheet discharge state.
(C) and (D) are schematic diagrams showing different operations.

FIG. 7 is a schematic view showing a state of shifting from reverse to normal paper discharge, in which (a) and (b) show different operations.

[Explanation of symbols]

 2 Paper Feed Roller 3 Registration Roller (Registration Section) 7 Fixing Roller 8 Inversion Switching Claw 9 Inversion Roller 10 Inversion Stocker 11 Paper Ejection Roller

Claims (3)

[Claims] 1. An automatic reversing device of a digital copying machine, wherein printed paper can be selectively discharged on the front surface and the back surface, and means for storing the surface of the paper discharged one sheet before.
A means for detecting the paper size in advance and a means for storing the paper size of the previous sheet are provided, and when the previous sheet is the reverse ejection paper and the next is the non-reversal ejection paper sheet, the stored previous paper sheet An automatic reversing device for a digital copying machine, which has a function of holding the paper to be ejected next time according to the size in a resist section for a required time. 2. A means for measuring the elapsed time after the trailing edge of the paper passes through the resist portion is provided, and the paper to be discharged next is
2. The automatic reversing device for a digital copying machine according to claim 1, wherein the automatic reversing device of the digital copying machine is provided with a function of making the resist portion stand by by the difference between the elapsed time of the previous sheet passing through the resist portion and the stored paper size. 3. A means for measuring the time for which the paper passes through the resist portion and a means for holding the measured time are provided, and when the paper whose length cannot be detected reaches the resist portion in advance,
3. The automatic reversing device for a digital copying machine according to claim 2, further comprising a function of controlling a waiting time at the registration section according to a sheet discharge surface of the previous sheet, a registration section passage time of the sheet, and a passage elapsed time.