JP2003201035A - Paper feed controlling method for image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper feed controlling method for an image forming device enabling to avoid overlapping sending of transfer-paper to be conveyed. <P>SOLUTION: In this image forming device having a paper feeding mechanism capable of conveying transfer-paper 2 stacked in a paper feed tray 7 one by one from the top layer with a feed roller 3 and reversely conveying a transfer- paper 2a following under the transfer-paper 2 to be conveyed toward the paper- feed-tray 7 with a reverse roller 4, a paper feeding sensor 5 is disposed in the vicinity of the downstream side of the feed roller 3. The feed roller 3 can be stopped rotating with a clutch. After conveying the transfer paper 2 to the mounting part of the paper feeding sensor 5, the feed roller 3 is stopped for a while and started to rotate when a predetermined time has passed for conveying the transfer paper 2 to an image formation part. When a separating mode is chosen from the separating mode and a normal mode, the time T1 to stop the feed roller 3 is set longer than when the normal mode is chosen, and time that the reverse roller 4 can reversely convey the transfer-paper 2a is extended. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feed control method for an image forming apparatus applied to a copying machine, a printer, a facsimile or the like.

[0002]

2. Description of the Related Art FIG. 2 shows an example of an FRR sheet feeding mechanism of an image forming apparatus such as a copying machine, a printer or a facsimile. In this sheet feeding mechanism, a pickup roller 1 which rotates in a forward direction and moves up and down. A drive force is applied to the transfer paper 2 sent from the paper feed tray 7 by the feed roller 3 that rotates in the same direction as the pickup roller 1 and a direction in which the transfer paper 2 is fed backward, but the torque limiter operates. At times, the reverse roller 4 which can be rotated in accordance with the rotation of the feed roller 3 is sandwiched between these rollers 3,
Upper and lower grip rollers 6 provided on the downstream side in the sheet feeding direction of 4
Then, the transfer paper 2 is fed to the image forming unit.

The pickup roller 1 is moved up and down by exciting and releasing the electromagnetic coil, and the drive of the feed roller 3 is controlled to be turned on and off by engaging and disengaging the electromagnetic type sheet feeding clutch. Has been done.
Further, near the downstream side of the feed roller 3 in the sheet feeding direction, a sheet feeding sensor 5 for detecting the presence or absence of the transfer sheet 2 at that position is provided.

In the paper feed mechanism shown in FIG. 2, when the transfer paper 2 sent from the pickup roller 1 is followed and another transfer paper 2a below the transfer paper 2a is about to be sent out, the reverse roller 4 moves downward. The transfer paper 2a is fed back to the paper feed tray 7 side,
Overrunning in which the transfer sheets 2 and 2a are simultaneously sent out is prevented.

[0005]

However, when the transfer papers 2 and 2a have a high adhesion between the sheets such as the second original sheet and the OHP sheet, or even the normal paper, the humidity control Depending on the state, the transfer paper 2 to be sent out
In some cases, the lower transfer paper 2a following the above cannot be completely returned to the paper feed tray side by the reverse roller 4, resulting in heavy running.

The present invention has been made in view of the above-mentioned circumstances, and provides a paper feed control method for an image forming apparatus, which aims to avoid overrun of a transfer paper to be sent.

[0007]

In order to achieve the above object, the invention according to claim 1 is to transfer the transfer papers stacked in a paper feed tray one by one from a top layer by a feed roller and to be transferred. Equipped with a paper feed mechanism that can reversely feed the transfer paper that follows the lower side to the paper feed tray with a reverse roller, a paper feed sensor is installed near the downstream side of the feed roller, and the feed roller can stop rotation by a clutch,
In the image forming apparatus that conveys the transfer sheet to the image forming section after the transfer sheet is conveyed to the sheet feeding sensor installation section, the feed roller is once stopped and is rotated again after a time T1, in the normal mode and the judgment mode. The most main feature is the paper feed control method of the image forming apparatus in which the time T1 for temporarily stopping the feed roller is set longer when the search mode is selected than when the normal mode is selected.

According to the second aspect of the present invention, it is possible to select the type of the transfer paper to be sent out, and when the transfer paper having a high sheet-to-paper adhesion is selected, the feed roller is temporarily stopped and then rotated again. The main feature is the paper feed control method of the image forming apparatus in which the time T1 is set longer than that of normal transfer paper.

According to the third aspect of the invention, when a specific paper feed tray is selected from among a plurality of paper feed trays, the time T1 until the feed roller is once stopped and then rotated again
The main feature is the paper feed control method of the image forming apparatus, in which is set longer than the normal paper feed tray.

A fourth aspect of the present invention is characterized mainly in a paper feed control method for an image forming apparatus, which changes a preset time T1 to an arbitrary value.

In any one of the first to fourth aspects of the present invention, when the sorting mode is selected, the time during which the reverse roller can reversely feed the following transfer paper is extended to avoid the overrun of the transfer paper. Further, when the normal mode is selected, the time during which the reverse transfer paper of the reverse roller can be fed back is returned to the normal value, and the decrease in the paper feeding efficiency is suppressed.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a timing chart when an example of an embodiment of a paper feed control method for an image forming apparatus of the present invention is applied to the paper feed mechanism of FIG.

In this paper feed control method, the user can arbitrarily select the normal mode and the judgment mode using the operation unit or the like.

Whichever of the above modes is selected, the pickup SOL (electromagnetic coil) and the sheet feeding clutch are turned on by the sheet feeding signal output upon activation of the image forming apparatus, and the pickup roller 1 and the feed roller are fed. The roller 3 and the reverse roller 4 send the transfer paper 2 from the paper feed tray 7. When the leading edge of the transfer paper 2 reaches the paper feed sensor 5 installation portion, the paper feed sensor 5 is turned on, and the paper feed clutch is turned off accordingly.

At this time, the feed roller 3 is stopped, but since the reverse roller 4 is constantly rotated in the direction for feeding the transfer paper 2 backward, a space between these rollers 3 and 4 is provided. When another transfer paper 2a that follows the lower side of the transfer paper 2 to be sent out is inserted in the nip portion, the transfer paper 2a is fed back to the paper feed tray 7 side by the rotation of the reverse roller 4.

Then, after a lapse of time T1, the paper feed clutch is turned on, and the feed roller 3 and the reverse roller 4 are turned on.
The transfer paper 2 held between the upper and lower grip rollers 6
The paper is fed to the image forming section through the space between
When the paper feed sensor 5 installation section is passed, the paper feed sensor 5 turns off.
To do. Therefore, the paper feed sensor 5 is ON during the time T2 from when the paper feed clutch is OFF until the trailing edge of the transfer paper 2 passes the paper feed sensor 5 installation portion.

When the user selects the judgment mode, the time T1 is set longer than in the normal mode. As a result, the transfer papers 2 and 2a follow the transfer paper 2 to be delivered even when the mutual adhesion of the sheets such as the second original drawing sheet and the OHP sheet is high, or even the normal paper whose humidity control state is not good. The time during which the other transfer paper 2a that has been transferred can be fed back to the paper feed tray 7 side by the reverse roller 4 is extended,
It is possible to avoid the double running of the transfer papers 2 and 2a.

On the other hand, when the adhesion between the transfer papers 2 and 2a is low, the user selects the normal mode to shorten the feeding interval of the transfer papers 2 and lower the paper feeding efficiency. There is no.

Further, the type of the transfer papers 2, 2a can be selected, and the time T1 is preset depending on the type, or the type of the transfer papers 2, 2a for each of the plurality of paper feed trays 7 can be changed. If you set the time T1 in advance,
Operability is improved. In addition to this, the preset time T
If 1 can be adjusted appropriately, depending on the state of the transfer papers 2 and 2a, the environment in which the image forming apparatus is installed, and the state of the paper feeding mechanism, overrun does not occur and the paper feeding efficiency is remarkably high. The time T1 that does not decrease can be obtained.

The paper feed control method for the image forming apparatus of the present invention is not limited to the above-described embodiment, and it goes without saying that changes can be made without departing from the paper of the present invention.

[0021]

As described above, according to the sheet feeding control method of the image forming apparatus of the present invention, various excellent effects as described below can be obtained.

(1) In any one of the first to fourth aspects of the invention, when a double feed is apt to occur on the transfer paper due to the state of the transfer paper or the like, the judgment mode is selected. As a result, the time T1 during which the reverse roller can reversely feed the follower transfer sheet is extended, and the double running of the transfer sheet can be avoided.

(2) When the normal mode is selected, the reverse feed time T1 of the follower transfer paper of the reverse roller is set.
Returns to a normal value, and it is possible to suppress a decrease in sheet feeding efficiency.

(3) In the invention according to claim 2, the type of transfer paper is selectable, and the time T1 is set in accordance with the type.
Is set, the operability of the image forming apparatus is improved.

(4) In the invention according to claim 3, the time T1 is set for each of the plurality of paper feed trays in accordance with the type of transfer paper.
Is set, the operability of the image forming apparatus is improved.

(5) In the invention described in claim 4, since the set time T1 can be adjusted appropriately, the state of the transfer paper,
Depending on the environment in which the image forming apparatus is installed and the state of the sheet feeding mechanism, a time T1 in which overrun does not occur and the sheet feeding efficiency is not significantly reduced can be obtained.

[Brief description of drawings]

FIG. 1 is a timing chart in an example of an embodiment of a paper feed control method for an image forming apparatus of the present invention.

FIG. 2 is a conceptual diagram showing an example of a paper feed mechanism of the image forming apparatus.

[Explanation of symbols]

2 Transfer paper 2a Transfer paper 3 feed rollers 5 Paper feed sensor 7 Paper tray

Claims (4)

[Claims] 1. Transfer sheets stacked on a paper feed tray are fed one by one from a top layer by a feed roller, and transfer papers following the lower side of the transfer paper to be fed can be fed back to the paper feed tray by a reverse roller. Equipped with a paper feed mechanism, a paper feed sensor is installed in the vicinity of the downstream side of the feed roller, and the feed roller can be stopped rotation by a clutch.After conveying the transfer paper to the paper feed sensor installation section, stop the feed roller once. In the image forming apparatus that rotates again after the time T1 and conveys the transfer paper to the image forming unit, when the judgment mode is selected from the normal mode and the judgment mode, the time T1 for temporarily stopping the feed roller is set to the normal mode. A paper feed control method for an image forming apparatus, characterized in that it is set longer than when selected. 2. When the type of transfer paper to be sent out can be selected and the transfer paper having a high paper-to-paper adhesive force is selected, the time T1 from when the feed roller is once stopped to when it is rotated again is The paper feed control method for an image forming apparatus according to claim 1, wherein the paper feed control method is set to be longer than the transfer paper. 3. When a specific paper feed tray is selected from among a plurality of paper feed trays, a time T1 until the feed roller is once stopped and then rotated again is set longer than a normal paper feed tray. The paper feed control method for the image forming apparatus according to claim 1. 4. The paper feed control method for an image forming apparatus according to claim 1, wherein the preset time T1 is changed to an arbitrary value.