JP3871169B2 - Paper folding device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sheet folding apparatus including a swing fin that applies a folding force to a continuous sheet provided with folds.
[0002]
[Prior art]
FIG. 2 illustrates a laser beam printer as a typical apparatus to which the paper folding apparatus is applied. When a printing operation start signal is issued to the laser beam printer from a controller that controls the laser beam printer, the photosensitive member 1 starts rotating. The photoreceptor 1 rotates at a speed corresponding to the printing speed of the laser beam printer and continues to rotate until the printing operation is completed. When the photosensitive member 1 starts rotating, for example, a positive high voltage is applied to the charger 2, and the surface of the photosensitive member 1 is uniformly charged with positive charges. The polygon mirror 3 is a polyhedral reflecting mirror that starts rotating as soon as the printer is turned on. The polygon mirror 3 rotates at a constant speed with high precision as long as the power is turned on. Light is reflected by the polygon mirror 3 and irradiated while scanning the surface of the photoreceptor 1 through the Fθ lens 5.
[0003]
Characters and graphic data converted into dot images are issued from the controller to the laser beam printer as a laser light on / off signal, and a portion where the laser light is irradiated and a portion where the laser light is not irradiated are formed on the surface of the photosensitive member 1. When the laser beam is irradiated, the charge on the photosensitive member 1 disappears, and when the portion reaches the front of the developing device 6, the positively charged toner is attracted by static electricity and a toner image is formed on the photosensitive member 1. At the timing when the top of the print data formed on the photosensitive member 1 by the laser beam comes before the transfer unit 7, the top of the paper 13 on which the data is printed (paper folding perforation) is before the transfer unit 7. The tractor 8 is driven so as to move.
[0004]
The tractor 8 transports the sheet 13 from the hopper unit to the fixing unit through the developing unit including the photosensitive member 1, the developing device 6, and the transfer unit 7. The sheet 13 that has reached the fixing device 9 is preheated by the preheating plate 10 and then conveyed while being heated under pressure by the heat roller 11 and the pressure roller 12, whereby the toner image is melted and fixed on the sheet 13. The printed paper 13 is folded by the swinging motion of the swing fin 14 according to the folding perforation, and then stacked on the stacker table 16 while being folded by the rotating paddle 15.
[0005]
FIG. 3 shows a conventional swing fin unit. The rotation of the stepping motor 30 is decelerated by the gear head 31. The rotation of the motor is transmitted to the pulley 33 fixed to the swing fin shaft 34 by the timing belt 32. The swing fin 14 is fixed to the swing fin shaft 34. That is, in the swing fin unit, to swing the swing fin 14, the stepping motor 30 may be rotated by switching the rotation direction in the CW / CCW direction. Accordingly, the swing angle of the swing fin 14 can be freely selected by managing the number of operation steps of the stepping motor 30.
[0006]
An encoder plate 37 is fixed to the swing fin shaft 34 and detects the position of the swing fin 14 based on the positional relationship with the photo interrupter 36. In the conventional example, the position where the swing fin 14 is directed downward will be described as a basic position (hereinafter referred to as “home position”).
[0007]
Control of the swing fin unit according to the conventional example will be described with reference to FIGS. 4, 5, and 6. When a signal P FEED-P indicating that paper feeding is being executed rises in synchronization with the DVS-P signal generated at a period corresponding to the time for feeding 1/6 inch paper as a signal inside the printer, the microcomputer 38 In addition, a signal SWING DRV-P for operating the stepping motor 30 is issued to the stepping motor control unit 39. This signal rises in synchronization with the first input DVS-P signal after P FEED-P rises.
[0008]
In this configuration, a timing chart when the swing fin 35 starts to move in the CCW direction from the home position is shown. The microcomputer 38 issues a CW-P signal at the “L” level to move the stepping motor 30 in the CCW direction. Further, every time the stepping motor 30 is operated by one step, the microcomputer counts up a counter for counting the number of steps by one.
[0009]
As shown in FIG. 5, if the turning point on the CCW side is n, the swing fin 35 operates toward the CCW side until the counter value reaches n, and SWING DRV-P becomes “L” and the swing fin 35 becomes Stop. Next, when TURN-P is input, CW-P becomes “H” in order to operate the swing fin 35 in the CW direction. After the TURN-P signal is input, the swing fin drive is resumed by the first DVS-P input. The TURN-P signal is issued at a paper feed time interval corresponding to the paper length of the paper to be printed, and the issue timing is to count the DVS-P signal so that the swing fin 35 should reach the turning point. Managed by. In FIG. 5, m is the count value.
[0010]
In the process in which the swing fin 35 moves in the CW direction, the signal HOME-P from the home position sensor consisting of the encoder plate 37 and the photo interrupter 36 changes from “L” to “H”, forcing the counter to 2n. To correct. Similarly, the swing fin 14 is controlled and turned back at the point of the counter 3n, and when the HOME-P changes from “H” to “L”, the counter is forcibly rewritten to 0.
[0011]
If the swing fin 14 is in operation at the time of receiving the TURN-P signal, it immediately stops and waits for the next DVS-P. When P FEED-P is finished and the paper feeding operation is completed, the swing fin 14 is stopped by passing SWING DRV-P in response to the next DVS-P signal input.
[0012]
As described above, the position information of the swing fin 14 is corrected by clearing the counter in response to the detection of the home position, and the return timing is determined by the TURN-P signal. It is possible to correct a large phase shift. Further, by having a value of the turning point n for each paper length, a swing angle corresponding to the paper length can be selected. Since the swing angle is small for a short paper length and the swing angle is large for a long paper length, the rotation speed of the stepping motor 30 is substantially constant. In FIG. 9, the operation | movement outline | summary of the swing fin 14 controlled by the above-mentioned is shown.
[0013]
[Problems to be solved by the invention]
In the above-described conventional control, the return timing of the swing fin 14 is the same timing regardless of the paper feed speed. That is, the value of m at which the TURN-P signal is generated in FIG. 5 is determined so that it is generated at the timing when the position of the fold perforation passes the same position with respect to the tip of the swing fin 14.
[0014]
FIG. 6 shows the relationship between the speed of the swing fin 14 and the paper feed time t. A timing 55 indicated by A in FIG. 6 is a timing at which the perforation passes through the tip of the swing fin. The solid line 51 in the figure is the ideal speed of the swing fin 14, and the broken line 52 is the speed of the swing fin when the motor that drives the swing fin is controlled by rotating forward / reversely and does not require the motor start-up time. The dotted line 53 indicates the speed of the swing fin when the motor is required to rotate forward / reversely, and the solid line 54 is controlled by rotating the motor driving the swing fin in one direction by the link mechanism. This is the speed of the swing fin. As shown by the solid line 51, the swing fin 14 is ideally changed in speed from V to -V at the timing 55, but in an actual system including the method shown in the conventional example, a delay always occurs. .
[0015]
For example, even in the case of a link method in which the motor is rotated and controlled in one direction and the motor does not need to be reversed, the point at which the tip of the swing fin 14 switches the moving direction is the direction of the swing fin rotation circumferential tangent Since the speed becomes slow, a delay corresponding to the area 58 indicated by C in the figure and a loss time 58 occur. In addition, when a forward / reverse rotation is performed using a stepping motor as described as a conventional example, a start-up time is required, or as described in FIG. 5, a swing is performed after a TURN-P signal is output. A certain control time (including processing time for a microcomputer or the like) is required until the fin motor 30 starts rotating.
[0016]
When the paper feed speed is constant, it is necessary to set the value of m in FIG. 5 to a value that takes into account the loss time 58 in consideration of this delay, and thereby reverse the swing fin 14. By adjusting the timing, the paper can be folded so as not to jam.
[0017]
However, when the paper feed speed changes, such as a printer having a plurality of paper feed speeds or a post-processing device connected to a printer with various paper feed speeds, the value of m is constant, that is, the swing fin inversion timing and In the conventional control in which the positional relationship between the tip of the swing fin 14 and the perforation is constant at that timing, it is difficult to achieve stable paper folding at all paper feed speeds.
[0018]
SUMMARY OF THE INVENTION An object of the present invention is to provide a paper folding device that is less likely to cause paper jam at various paper feed speeds and can realize a stable folding operation.
[0019]
[Means for Solving the Problems]
The above object is achieved by a sheet folding device including a swing fin that is supported in a swingable manner and applies a folding force to a continuous sheet provided with a fold. The continuous sheet is fed at a first feed speed (W). When transporting, the swing motion of the swing fin is reversed at the timing when the fold of the continuous paper reaches the upstream in the continuous paper transport direction by a first distance (T1) with respect to the tip of the swing fin. When the continuous paper is conveyed at a second feed speed (W ′) that is faster than the first feed speed, the fold of the continuous paper is smaller than the first distance with respect to the tip of the swing fin. This is achieved by having a control means for reversing the swinging motion of the swing fin at a timing when it reaches the upstream in the continuous paper transport direction by a long second distance (T2) .
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Examples of the present invention will be described below. Since the basic configuration is the same as that of the conventional example, a description thereof will be omitted, and the control of the swing fin will be described below.
[0021]
In this embodiment, a case where the mechanism shown in FIG. 3 can be operated at a usable speed without slowing up the stepping motor will be described as an example. FIG. 7 and FIG. 8 show actual swing fin delay time (loss time) with respect to the ideal speed of the swing fin when the paper feed speed (shown as W and W ′ in the figure) changes.
[0022]
FIG. 7 shows a case where the paper feed speed is slow, and FIG. 8 shows a case where the paper feed speed is faster than FIG. In FIG. 7 and FIG. 8, a region B58 is a loss time that occurs when the swing fin is reversed and started up. In this embodiment, the stepping motor is slowed up, so that it is a control delay time of a stepping motor controller such as a microcomputer. is there.
[0023]
Even if the paper feed speed changes, this loss time generally does not change. However, as is apparent from FIGS. 7 and 8, the loss time 57 shown in the region B58 increases as the paper feed speed W increases. In the present invention, the value of m in FIG. 5, that is, the value of T in FIG.
[0024]
【The invention's effect】
As described above, according to the present invention, the swing fin return timing is changed depending on the paper feed speed, so that stable folding performance with less paper jam can be obtained.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of swing fin turn-back timing according to the present invention.
FIG. 2 is a schematic diagram of a laser beam printer.
FIG. 3 is a perspective view of a swing fin unit.
FIG. 4 is a block diagram of a swing fin drive unit.
FIG. 5 is an explanatory diagram of swing fin operation timing.
FIG. 6 is an explanatory diagram showing the relationship between swing fin return timing and swing fin speed.
FIG. 7 is an explanatory diagram showing a relationship between swing fin return timing and swing fin speed when the paper feed speed is low.
FIG. 8 is an explanatory diagram showing the relationship between swing fin return timing and swing fin speed when the paper feed speed is high.
FIG. 9 is an explanatory diagram of swing fin operation.
[Explanation of symbols]
14 is a swing fin, 15 is a paddle, and 16 is a stacker table.

Claims (1)

In a paper folding device provided with swing fins that are supported so as to be swingable and that impart folding force to continuous paper provided with folds ,
When the continuous paper is conveyed at the first feeding speed (W), the fold of the continuous paper reaches the upstream in the continuous paper conveyance direction by a first distance (T1) with respect to the tip of the swing fin. When the swinging motion of the swing fin is reversed at the timing and the continuous paper is transported at the second feed speed (W ′) higher than the first feed speed, the fold of the continuous paper is Control means for reversing the swinging motion of the swing fin at a timing when it reaches the upstream in the continuous paper transport direction by a second distance (T2) longer than the first distance with respect to the tip of the swing fin. Paper folding device.

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