JPH02310066A - Drive controller for paper feeder - Google Patents

Abstract

PURPOSE:To eliminate a noise caused by an expansion of a deflected part of paper at the start of a resist roller and to prevent the occurrence of paper feeding error, paper folding, and wrinkle by controlling a paper feed amount to a proper amount in accordance with the thickness and feed speed of paper. CONSTITUTION:With the detection of the leading end of fed paper P by a paper sensor 60, a feed mode for the paper P is judged by a control means 70 on the basis of the feed speed and thickness of the paper P. The control means 70 controls a drive time so as to stop the power supply to a pulse motor 51 at a timing appropriate for the leading end of the paper P reaching a nip part of a resist roller 3 to be fed by a slight amount to generate a small deflection in a tissue high-speed mode, or at the latest timing in a thick-paper low-speed mode wherein the secure insertion of the paper P into the nip part of the resist roller 3 is most hard to obtain. The fed paper P is waited with the leading end thereof securedly inserted in the nip part of the resist roller 3, and the resist roller 3 is driven at the predetermined timing.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a drive control device for a paper feeding device in a printing machine, a copying machine, etc.

(Prior Art) A type of paper feeding device in printing machines, copying machines, etc. is a paper feeding device that feeds paper by rotationally driving the peripheral surface of the paper in contact with the topmost paper stacked on a paper feeding table. A paper separating and transporting means that prevents double feeding of sheets using a roller, a paper separation and transport roller that transports the paper fed by the paper feed roller, and a friction separation plate that elastically presses against the circumferential surface of the paper separation and transport roller. and a registration roller that feeds the paper separated and conveyed by this paper separation and conveyance means to a paper processing section (impression cylinder in the case of a printing machine, photoreceptor in the case of a copying machine) at a predetermined timing. Paper devices are known.

In addition, as a drive control device that controls the drive of the paper feed roller and paper separation/conveyance roller of this type of paper feed device, a sensor that detects the paper position is provided near the registration roller, and this sensor detects the paper position. A device configured to, upon detection, stop power supply to the drive motor of the paper feed roller, etc., or disconnect the drive transmission system of the clutch that transmits the rotation of the drive motor to the paper feed roller, etc. 1! (Japanese Patent Publication No. 56-51977) Alternatively, an enlarged width section that allows the deflection of the paper is formed on the paper guide plate between the paper separation and conveyance roller and the registration roller, and this enlarged width section is used to prevent the deflection of the paper. Install a sensor to detect it.

A device (specifically, a device for stopping the drive of the paper separation and conveyance rollers, etc. Kosho 62-15711
15 Publication), etc. are known.

Paper feeding devices equipped with these conventional drive control devices, for example, use a combination of cams, fan-shaped gears, etc., or set the amount of rotation of the paper feeding roller in advance using the rotation speed of the motor, etc., so that the paper is fed the same distance each time. Compared to a paper feeding device that feeds paper, it is possible to transport the paper more reliably.

In other words, in paper feeding devices such as printing machines, in order for the registration rollers to feed the paper toward the impression cylinder (photoreceptor in copying machines) at a predetermined timing, the registration rollers are loaded before the registration rollers start. Even after the leading edge of the paper reaches the nip portion of the rollers, the paper feed roller and the paper separation/conveyance roller are driven slightly open to correct skew during paper conveyance. Therefore, in this type of paper feeding device, the paper is bent before it is fed by the registration rollers, and the stiffness of the paper is used to push the registration rollers at the leading edge of the paper. conveyance force to the nip portion can be obtained.

However, in a paper feeder in which the paper transport distance is set to a certain amount in advance, slipping occurs between the paper feed roller and paper separation transport roller and the paper due to variations in the coefficient of friction between the sheets, causing the paper to be transported. When the actual conveyance distance of the sheet becomes shorter than the set conveyance distance, the driving of the sheet feed rollers etc. is stopped before the leading edge of the sheet reaches the nip portion of the registration rollers, and a sheet feeding error occurs.

The drive control device stops driving the paper feed rollers, etc. after the sensor detects that the leading edge of the paper has reliably reached the nip portion of the registration rollers, so that the above-mentioned problems can be prevented.

(Problems to be Solved by the Invention) By the way, the conventional drive control device for the paper feed device described above controls the drive of the paper feed roller, etc. based on the output of the sensor that detects the position of the leading edge of the paper or the sensor that detects the deflection of the paper. Since the drive is controlled, it can only be used in paper feeding devices where the paper conveyance speed and thickness are approximately constant. Although it can be applied to copying machine paper feeding devices, There is a problem with this method, which makes it unsuitable as a drive control device for a paper feeding device whose conveyance speed and thickness are variable.

In other words, when this drive control device is installed in the paper feed device of a printing press, even if the drive of the paper feed roller, etc. is stopped by the output of the above sensor, the inertia of the roller drive system will affect the high speed of the paper. There is a difference in the conveyance distance of the paper after the rollers stop during printing and during low-speed printing, and the amount of paper deflection during high-speed printing is greater than the amount of paper deflection during low-speed printing. There is a drawback that the sound generated by the stretching of the flexible portion of the paper becomes noise during high-speed printing. Furthermore, if the paper is thick, it becomes difficult for the leading edge of the paper to enter the nip of the registration rollers under the same conditions as when transporting thin paper, making it more likely that paper feeding errors will occur. here.

If the roller driving time after sensor detection is set to be long so that thick paper is reliably transported, the amount of transport for thin paper becomes too large, and folds or wrinkles are likely to occur at the leading edge of the paper. Further, since cardboard has high rigidity and is not easily bent, it is not possible to use a method of detecting the bending of the paper with a sensor and controlling the drive of a paper feed roller or the like.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention detects the leading edge and thickness of paper in the paper conveyance path upstream of the registration 1 roller in the paper feeding device. A paper leading edge/thickness detection means is provided, and based on the output of the paper leading edge/thickness detection means and the paper conveyance speed, the paper feed means and paper separation/conveyance after the paper leading edge is detected by the paper leading edge/thickness detection means. The drive time of the means is controlled by the sheet conveyance drive control means to an appropriate time required for the leading edge of the sheet to reach the nip of the registration rollers.

(Function) According to the present invention, based on the output of the paper leading edge/thickness detecting means and the paper conveyance speed, the drive time of the paper feeding means and the paper separation conveyance roller, that is, the conveyance amount of the paper, is determined based on the paper thickness. It is controlled to have an appropriate amount according to the conveyance speed.

(Example) Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 shows an example in which the present invention is implemented in a paper feeding device of an offset printing press.

The paper feeding device in this offset printing machine includes paper feeding means 1.
．． It is comprised of a paper separation and conveyance means 2, registration rollers 3, paper guide plates 4, and the like.

The paper feed unit 1 includes a paper feed roller 11 that feeds paper P that is difficult to place on a paper feed tray (not shown), a drive system that drives this paper feed roller 11, and a drive system that drives the paper P loaded on the paper feed tray (not shown). It consists of a paper lifting device that raises and lowers the paper.

The paper separation and transport means 2 includes a paper separation and transport roller 21 that transports the paper fed by the paper feed roller 11, a friction separation plate 22 that elastically presses against the circumferential surface of the paper separation and transport roller 21, and a paper separation and transport roller 21 that transports the paper fed by the paper feed roller 11. It is composed of a drive system for conveyance rollers 21.

The drive system for the paper feed roller 11 in this paper feed device also serves as the drive system for the paper separation and conveyance roller 21, and includes a pulse motor 51, timing pulleys 52, 53, 5.
4.55 and a timing belt 56.57.

The timing pulley 52 is connected to the output shaft 5 of the pulse motor 51.
It is fixed at 1a. The timing pulley 53 is attached to the end of the support shaft 21a of the paper separation and conveyance roller 21 via a one-way rotation clutch. These timing pulleys 52 and 53 are connected by a timing belt 56, and when the pulse motor 51 is driven, the paper separation and conveyance roller 21 is rotated counterclockwise in FIG. In addition, other timing pulley 54
is attached to the support shaft 21a near the paper separation and conveyance roller 21. Still another timing pulley 55 is attached to the support shaft 11a of the paper feed roller 11. These timing pulleys 54 and 55 are connected by another timing belt 57, and as described above, when the paper separation and conveyance roller 21 is rotationally driven, the paper feed roller 11 is rotationally driven in the same direction. Each support shaft 11a, 21
a is rotatably supported by a support member 58 (see FIG. 2) provided in the main body of the apparatus.

On the other hand, the registration roller 3 is composed of a pair of rollers, and these rollers are moved to a predetermined position by a driving means (not shown) on a support shaft 3a (see FIG. 2) that is rotatably suspended horizontally on the side plate of the main body of the apparatus. By being driven by timing,
In FIG. 1, they are driven in the directions of the arrows.

The paper guide plate 4 is a paper transport path A that connects the contact point between the paper separation transport roller 21 and the friction separation plate 22, the nip part of the registration roller 3, and the contact part between the blanket cylinder 5 and the impression cylinder 6 of the printing machine. is formed by a pair of flat plates.

The drive control device according to the present invention includes a paper leading edge/thickness detection means 60 for detecting the leading edge and thickness of the paper P, and a paper conveyance drive control means 70.

The paper leading edge/thickness detection means 60 is disposed in the paper transport path A upstream of the registration roller 3, and specifically,
At the part of the paper guide plate 4 upstream of the registration roller 3,
Light sources 60 are arranged facing each other across the paper conveyance path A.
It is composed of a transmission type photosensor consisting of a light receiving element 60b and a light receiving element 60b. The paper leading edge/thickness detecting means 60 (hereinafter simply referred to as a paper sensor) may be constituted by a contact type angle sensor. This paper sensor 60 has a function of determining the presence or absence of paper P and a function of determining the thickness of paper P. Here, the presence or absence of the paper P is determined based on the presence or absence of a change in the output value (generally resistance value) of the paper sensor 60, and the thickness of the paper P is determined based on the magnitude (change in the output value of the paper sensor 60). It is done depending on the size of the amount). The output of this paper sensor 60 is given to paper conveyance drive control means 70 (hereinafter simply referred to as control means).

The control means 70 controls the output of the paper sensor 60 and the paper P.
Based on the conveyance speed, the drive time of the paper feed means 1 and the paper separation and conveyance means 2 is controlled to an appropriate time required for the leading edge of the paper to reach the nip portion of the registration rollers 3.

Here, the transport speed of paper P is as in the case of a printing machine,
Normally, when two speeds, high speed and low speed, are preset, it is necessary to specify whether the transport mode of paper P is high speed mode or low speed mode, and input that information to the control means 70. Just leave it as . In addition, in the case of a printing machine, a copying machine, etc. that does not specify the transport mode of the paper P, the time required from the output of the paper feed start signal of the paper P until the paper sensor 60 outputs the paper leading edge detection signal is The time may be measured by a timer built into the control means 70, and the transport speed of the paper P may be calculated from this measured value. Therefore, this control means 70 controls when the paper P is thin paper and is being transported at a low speed (hereinafter referred to as thin paper low speed mode), and when the paper P is thick paper and is being transported at a low speed (hereinafter referred to as thick paper low speed mode). (referred to as low speed mode), paper P
Which mode corresponds to when paper P is thin paper and is transported at high speed (hereinafter referred to as thin paper high speed mode) or when paper P is thick paper and is transported at high speed (hereinafter referred to as thick paper high speed mode) It is determined based on the output of the paper sensor 60 and the transport speed of the paper P, and the paper feed means 1 and the paper separation and transport means 2 are driven for an appropriate driving time according to each mode. The specific drive control of the sheet feeding means 1 and the like is executed by giving a preset output to the pulse motor 51 according to each of the above-mentioned modes.

That is, in FIG. 1, a paper feed start signal is output,
When the pulse motor 5I is driven, as described above, the paper feed roller 11 rotates counterclockwise via the drive system, and at the same time, the top sheet P loaded on the paper feed tray is fed. The paper P is pressed against the circumferential surface of the roller 11 and fed toward the paper separation and conveyance means 2 . The fed paper P is prevented from double feeding by the rotation of the paper separation and conveyance roller 21 and the cooperation with the frictional separation plate 22, and then passes along the paper guide plate 4 to the registration rollers 3. transported towards.

When the leading edge of the transported paper P is detected by the paper sensor 60, the transport mode of the paper P is determined by the control means 70 based on the transport speed and thickness of the paper P, as described above. . Here, for example, when the conveyance motor for the paper P is in the thin paper high speed mode, the power supply to the pulse motor 51 is stopped after a predetermined period of time, and the rotation of the paper feed roller 11 and the paper separation and conveyance roller 21 is stopped. Here, the distance from the paper detection position of the paper sensor 60 to the nip portion of the registration roller 3 is the thinnest paper P.
When the paper P is transported at the highest speed (hereinafter referred to as the reference mode), the paper P is transported by the inertia of the drive system when the leading edge of the paper is detected by the paper sensor 60 and the power supply to the pulse motor 51 is stopped at the same time. The distance is set in advance to be the same as, or slightly shorter than, the distance.

The power supply stop timing of the pulse motor 51 during each of the above motes is determined to be an appropriate time set in advance based on the two reference modes. That is, in the case of the thin paper high speed mode, after the leading edge of the paper P reaches the nip portion of the registration rollers 3, it is transported slightly and causes a small deflection, and in the case of the thin paper low speed mode, , the rotational speed of the registration rollers 3 is also slowed down, so the paper P that has reached the nip of the registration rollers 3 is
At the timing when the amount of deflection of the paper P is equal to or slightly larger than that in the thin paper high speed mode, and in the case of the thick paper high speed mode, the paper P is less likely to be deflected.
Since the leading edge of the paper tends to enter the nip of the registration rollers 3 unreliably, in the thick paper low speed mode, the paper P enters the nip of the registration rollers 3 at a later timing than in the thin paper high speed mode. Since the approach of the pulse motor 51 is most likely to be uncertain, the drive time is controlled by the control means 70 so as to stop the power supply to the pulse motor 51 at the latest timing.

The sheet P conveyed as described above is placed on standby with its leading end securely entering the nip portion of the registration rollers 3. As is well known, the registration rollers 3 are driven at a predetermined timing to move the paper P between the blanket cylinder 5 and the impression cylinder 6 (in the case of a copying machine, between the photoreceptor and the transfer device). ), and after the image formed on the circumferential surface of the blanket cylinder 5 by the plate cylinder 7 is printed on the paper P,
The paper is discharged onto the paper discharge tray 8''2.

In addition, although the embodiment described in section 1 shows an example in which the pulse motor 51 is used as the drive source for the paper feed means 1, etc., the paper feed means 1 etc. are driven by a constantly rotating drive source, and this drive source is also used. An electromagnetic clutch may be disposed between the sheet feeding means 1, etc., and the driving time of the sheet feeding means 1, etc. may be controlled by connecting and disconnecting the electromagnetic clutch at the timings described above.

(Effects of the Invention) According to the present invention, the noise generated due to the stretching of the flexible portion of the paper at the time of starting the registration rollers is eliminated, and the occurrence of paper feeding errors and folding or wrinkles of the paper is prevented.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side view of an embodiment of the invention, and FIG. 2 is a partial plan view of FIG.

■...Paper feeding means, 2...Paper separation and conveyance means, 3
... Registration roller, 4 ... Paper guide plate, 60
. . . Paper leading edge/thickness detection means, 70 . . . Paper conveyance drive control means, A. . . Paper conveyance path, P .

Claims (1)

[Claims] A paper feeding means that feeds the paper stacked on the paper feed table, a paper separation and conveyance means that prevents double feeding of the fed sheets, and a paper separation and conveyance means that feeds the separated and conveyed sheets to the paper processing section at a predetermined timing. A paper feeding device having a registration roller that detects a paper leading edge and a thickness of the paper, and a paper leading edge/thickness detection means for detecting the leading edge and thickness of the paper, which is disposed in a paper conveyance path upstream of the registration roller; Based on the output of the means and the paper conveyance speed by the paper separation and conveyance means, the driving time of the paper feeding means and the paper separation and conveyance means after the paper leading edge/thickness detection means detects the paper leading edge is determined to be such that the leading edge of the paper reaches the registration roller. 1. A drive control device for a paper feeding device, comprising: control means for controlling a paper conveyance drive to an appropriate time required for paper to reach a nip portion.