JPH0126664Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a guide plate device for transfer paper in a copying machine, and particularly to a guide plate device in a paper conveyance path from a paper feed section to a registration roller, that is, a pre-transfer conveyance path. This relates to a plate device.

FIG. 1 is a schematic side view showing a general configuration of a pre-transfer conveyance path from a paper feed section to a registration roller.

In the figure, 1 is a cassette, 2 is a tray, and transfer paper stored in each is appropriately selected and fed into a paper conveyance path by paper feed rollers 3 and 4. 5 is a pressure lever that presses the transfer paper in the cassette 1 against the paper feed roller 3; 6 is an intermediate conveyance roller provided for the long lower tray 2 of the conveyance bus; and 7 is a synchronization lever between the photoreceptor 8 and the transfer paper. 9 is a transfer/separation charger, 1 is a registration roller for removing
Reference numeral 0 designates a guide plate that guides the transfer paper from each sheet feeding section of the upper cassette and lower tray to the registration roller 7, and 11 indicates a transfer guide plate that guides the transfer paper to the transfer section.

In the conveyance path configured in this way, the transfer paper is normally temporarily on standby with the leading edge of the transfer paper hitting the registration roller 7, but at this time, the transfer paper is allowed to bend to a certain extent. It is normal to let it stand. The reason for bending the transfer paper is to make the transfer paper sufficiently abut against the registration rollers 7 to correct skew feeding, and also to make the leading edge of the transfer paper fully grip the registration rollers 7. This is also to eliminate a timing delay when feeding the photoreceptor from the registration roller 7 toward the photoreceptor 8.

Therefore, if the amount of deflection is too small, the purpose just described cannot be achieved. However, if the transfer paper is bent too much, it may cause wrinkles or folds due to the relationship with the guide plate. Therefore, in order to prevent wrinkles and paper folds due to excessive deflection, guide plate devices have been proposed in which the guide plate is opened.

The conventional guide plate opening mechanism shown in FIGS. 2 and 3 will be described below.

What is shown in FIG. 2 is a movable guide plate 1 whose one end is coaxially supported with the lower roller of the registration roller 7.
The movable guide plate 12 has a structure in which a spring 13 applied with a weak tensile force is engaged with the movable guide plate 12, and the movable guide plate 12 is opened in the direction of the arrow when the transfer paper P is deflected.

In this conventional example, if the amount of deflection suddenly increases, the "stickiness" of the paper may become weaker and the movable guide plate 12 may not open.

Furthermore, the one shown in FIG. 3 is configured to open the movable guide plate 12 by a solenoid 14 serving as a driving means at a predetermined deflection timing (estimated in advance).

In this conventional example, since the deflection of the transfer paper P is not directly detected, there is a drawback that it cannot fully deal with variations in conveyance. That is, if the conveyance amount of the transfer paper P is small compared to the normal timing, the movable guide plate 12 may open before the leading edge reaches the registration rollers 7, and the transfer paper P may not be guided to the registration rollers 7. obtain. On the other hand, if the conveyance amount of the transfer paper P is too large compared to the normal timing, there is a risk that wrinkles or folds may occur before the movable guide plate 12 is released.

Of course, there is also a known technique in which the amount of deflection of the transfer paper is detected using a non-contact sensor to perform appropriate control. However, in this case, in addition to the high cost, there is also a deterioration in performance due to dirt.
One drawback is that it lacks reliability.

The present invention was developed in view of these drawbacks of the conventional technology, and for this purpose, only in the initial state where the transfer paper P is too deflected, the movable guide plate is directly slightly displaced by using the stiffness of the paper. After this, the movable guide plate is configured to be opened by the driving means upon detection of a minute displacement state.

An embodiment will be described below with reference to FIG.

FIG. 4a is a schematic side view showing the movable guide plate 15 in a normal state (closed state). The movable guide plate 15 is pivotally supported at its intermediate portion by the lower roller of the registration roller 7, and consists of pieces 15a and 15b. The piece 15b is for guiding the transfer paper P, and the piece 15a is engaged with or in contact with the driving means 17, the spring 16, and the micro switch 18. The spring 16 biases the movable guide plate 15 in the closing direction with a weak tensile force, and the solenoid 17, which is a driving means, is located on the opposite side of the spring 16 and biases the movable guide plate 15 in the direction of opening ( It is designed to be driven in the direction of the arrow). A microswitch 18 is in contact with one end of the piece 15a (normally closed type). In the guide plate device configured in this way, when the transfer paper P is deflected as shown in FIG.
is pressed, and the movable guide plate 15 is slightly displaced around the shaft support (as mentioned above, the elastic force of the spring 16 is set to be very weak, so the "firmness" of the paper due to an appropriate amount of deflection is due to this spring force. overcome). Therefore, when the piece 15a is separated from the terminal of the micro switch 18 and turned on, the solenoid 17 is turned on, and the movable guide plate 15 is opened wide by this tensile force. After the transfer paper P passes the registration roller 7, the solenoid 17 is turned off, and the movable guide plate 15 is closed again by the spring 16.

Figure 5 shows micro switch 18 and solenoid 1.
7 is a block diagram showing the relationship between on and off control of FIG. When micro switch 18 is turned on, _R1 and
A voltage level is set between R ₁ and R ₂ according to the voltage division ratio of R 2, and the I/O voltage level is set between R 1 and R ₂ according to the voltage division ratio of R ₂ .
It is input to the input port of O. The CPU (central control unit) controls this according to the program written in the ROM, and transfers data input from the I/O to the RAM.
At the same time, an on signal is output to the output port of the I/O, turning on the transistor _Q1 and driving the solenoid 17. R ₄ is a base resistance, and D ₁ is a back electromotive force prevention diode of the solenoid 17. As mentioned above, after the transfer paper P passes the registration roller 7, the solenoid 17 has to be turned off, but this is done at a timing based on the data stored in the RAM, and in consideration of other data in the CPU. This is done by controlling the I/O and sending an off signal to the output port of the I/O, turning off transistor _Q1 .

FIG. 6 is a timing chart of these. The registration roller 7 is turned on at a certain timing in the middle of the scanner (not shown), but prior to this, the micro switch 18 is turned on by the deflection of the transfer paper P, and at the same time drives the solenoid 17. However, while the registration roller 7 is being driven, the solenoid 17 is turned off by a signal from the control device, and as a result, the piece 15 of the movable guide plate 15
The micro switch 18 is turned off via a. The driving means is not limited to a solenoid, and an eccentric cam or the like may be used, and the detection means is not limited to a microswitch, but may be a piezoelectric switch, for example.

As mentioned above, the present invention directly detects the deflection of the transfer paper at an early stage when it is about to become excessive, and then releases the movable guide plate by external force. Compared to this, it is possible to reliably open the movable guide plate when the amount of deflection of the transfer paper is excessive, regardless of variations in the conveyance amount.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view showing the paper feed section of a copying machine, FIGS. 2 and 3 are explanatory views showing the main parts of a conventional example, and FIG.
The figure is an explanatory diagram of the main part showing one embodiment of the present invention,
5 is a control block diagram, and FIG. 6 is a timing chart. 7... Registration roller, 8... Photoconductor, 15...
...Movable guide plate, 17...Driving means, P...Transfer paper.

Claims (1)

[Scope of Claim for Utility Model Registration] During the paper conveyance path from the paper feed section to the registration rollers for synchronizing the photoreceptor and the transfer paper, rotating about the registration roller side as a base point,
A movable guide plate that is slightly displaced by the deflection of the transfer paper, a displacement detection means that detects the slight displacement of the movable guide plate, and when the displacement detection means detects the displacement of the movable guide plate, the movable guide plate is moved to the paper. 1. A guide plate device for transfer paper, comprising: a drive means that rotates so as to be released from a conveyance path.