JP2001114425A - Paper feeding device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably feed paper without being affected by the waviness of printing paper while restricting the causes of an operating timing of elevating up a feeding plate on an irregular basis. SOLUTION: A feeding roller 24 is rotated at a preset printing timing while contacting the uppermost surface of printing paper P to perform paper feeding. During paper feeding, an elevating means elevates up a feeding plate 26 until the upper most surface of the printing paper P is detected by an upper-limit sensor 5. A control means 1 prohibits the feeding plate 26 from being elevated up and holds it in the stopped condition during elevating up the feeding plate 26 when the feeding roller 24 is rotated. In this way, feeding pressure on the printing paper P is not changed if waviness occurs on the printing paper P during paper feeding, thus preventing paper feeding malfunction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeding apparatus and a method applied to a paper feeding section of a stencil printing machine or the like and capable of stably feeding printing paper.

[0002]

2. Description of the Related Art A printing machine such as a stencil printing machine feeds printing paper from a paper feeding unit and performs printing. In this paper feed unit,
A predetermined number of printing papers are stacked on a paper feed table, and the uppermost printing paper is fed one by one to the printing unit. The uppermost position of the printing paper when feeding paper is called the upper limit position, and the printing paper at this upper limit position contacts the paper feeding roller of the printing machine with a predetermined pressure and rotates when the paper feeding roller rotates. Paper is fed to the printer.

The setting of the upper limit position has a great influence on the paper feeding state. In the paper feeding state, stable paper feeding can be performed by keeping the position of the paper feeding roller and the position of the printing paper constant. If the upper limit of the printing paper is too high, double feeding will occur,
Conversely, if the upper limit position is too low, empty feeding occurs.

FIG. 6 is a perspective view showing the configuration of a sheet feeding device. The paper supply unit 53 is rotatable about a shaft 53 a, and when the paper supply table 51 rises, the print paper P contacts from below and lifts the paper supply unit 53 via the paper supply roller 54. The paper feed unit 53 is provided with an upper limit sensor 52 for detecting the upper limit position of the paper feed unit 53. The printing paper P on the uppermost surface is
The rotation of the third paper feed roller 54 (scraper roller 54a and pickup roller 54b) causes 1
Paper is fed one by one.

The upper limit sensor 52 detects the rotating state of the sheet feeding unit 53, and uses a microswitch or a photo interrupter integrated with light emitting and receiving. A configuration using a photo interrupter will be specifically described. The sheet feeding section 53 is provided with a shielding plate 55. With the rotation of the paper feeding unit 53, the shielding plate 55 shields or retreats the light emitting / receiving space of the upper limit sensor 52, and the output of the upper limit sensor 52 is turned ON / OFF.

When the upper limit sensor 52 is turned off, the sheet feeding table 51 is turned off.
Is controlled and raised until it is turned ON. The paper feed table 51 is controlled to rise / stop according to ON / OFF of the upper limit sensor 52. Similarly, in the case where a microswitch is used as the upper limit sensor 52, the feed tray 51 is controlled to rise in accordance with ON / OFF of the microswitch. As a result, during the printing period of the printing press,
The top surface of the printing paper P is maintained at a fixed upper limit position so that continuous feeding can be performed.

[0007]

When swelling occurs in the printing paper P when feeding the printing paper P, the upper limit sensor 52
However, there is a problem that the elevator motor for raising and lowering the sheet supply table 51 operates correspondingly. When the paper feed table 51 rises during the paper feeding period, the paper feed roller 5
The positional relationship between the sheet 4 and the paper surface of the printing paper P changes, and the paper feeding pressure generated between the paper feeding roller 54 and the paper surface of the printing paper P changes to cause a paper feeding failure.

For example, when the printing paper P is fed, the printing paper P
When the upper limit sensor 5 is temporarily turned off due to swelling, the elevator motor operates, the paper feed table 51 rises more than necessary, and double feed may occur on the next print paper P to be fed. . Further, when the printing paper P is fed, the paper feed mechanism and the printing unit may vibrate and the upper limit sensor 52 may be turned ON / OFF.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and regulates the cause of irregularly occurring timing of the operation of raising the sheet feeding table, thereby stabilizing the timing even when the influence of the undulation of the printing paper is obtained. It is an object of the present invention to provide a paper feeding device and a paper feeding method capable of feeding paper.

[0010]

In order to solve the above-mentioned problems, a paper feeder according to the present invention comprises a paper feed tray on which printing paper is loaded, elevating means for raising and lowering the paper feed tray, and a paper feed tray. Has a paper feed roller that contacts the uppermost surface of the print paper loaded on the paper and feeds the print paper one by one to the printing section at the position of the uppermost surface. The paper feed roller rotates at a predetermined timing during paper supply. A sheet feeding unit to be driven, and a control for inhibiting the sheet feeding table from being raised and holding the sheet feeding table in a stopped state while the sheet feeding roller is rotationally driven by the sheet feeding unit while the sheet feeding table is being raised. Means.

Further, the paper feeding means drives the paper feed roller to rotate at a predetermined timing interlocked with the rotation of the printing drum on which the stencil sheet made is mounted, and adjusts the rotation angle of the printing drum. An angle detecting means for detecting, the control means, based on the rotation angle of the printing drum detected by the angle detecting means, prohibits the rise of the paper feed table during the period when the printing paper is fed. It is also possible to adopt a configuration in which it is maintained in a stopped state.

According to the paper feeding method of the present invention, the printing paper loaded on the paper feeding table is fed one by one from the uppermost surface at a predetermined upper limit position, and the position of the uppermost surface of the printing paper is the upper limit. Raising the paper feed tray until the paper feed position is reached, and prohibiting the paper feed tray from being raised during the period in which the paper feed roller is rotationally driven while the paper feed tray is being raised, and holding the paper feed tray in a stopped state. Features.

According to the above configuration, the height of the uppermost surface of the printing paper P on the paper feeding table 26 is reduced by the feeding of the printing paper P. The elevating means raises the paper feed table 26 so that the position of the uppermost surface of the printing paper P becomes the upper limit position. The upper limit position of the printing paper P is detected by the upper limit position detecting means 5, and the paper feed table 26 is raised until the upper limit position is reached. Paper feed means 23
The paper feed roller 24 that contacts the uppermost surface of the printing paper P rotates at a predetermined timing to feed paper. The control unit 1 inhibits the paper feed table 26 from rising while the paper feed roller 24 is rotating while the paper feed table 26 is being raised, and holds the paper feed table 26 in a stopped state.

[0014]

FIG. 1 is a side view showing the entire configuration of a stencil printing machine to which a paper feeding device according to the present invention is applied. In this stencil printing machine, a printing drum 20 is disposed at a substantially central portion,
It is connected to the main motor M via a belt 25.
By the rotation of the main motor M, the printing drum 20 is rotatable in the direction A in the drawing. A perforated stencil sheet is mounted on the outer periphery of the printing drum 20. One end of the stencil sheet is held by a clamp plate 20a. One rotation of the printing drum 20 by driving the main motor M feeds, prints, and discharges one sheet of printing paper P.

The paper feeding unit is provided on one side of the printing drum 20 and facing the outside of the stencil printing machine. This paper supply section is roughly constituted by a paper supply means 23, a paper supply table 26, and an elevating means 28. The paper supply unit 23 includes a paper supply roller 24 and a paper supply clutch 32.

As shown in a partially enlarged view of FIG. 2, the paper feed roller 24 is supported by a support plate 23a. The support plate 23a and the paper feed roller 24 are entirely rotatable about the shaft 23b. The sheet feeding table 26 is moved by the elevating means 28.
Rises, the printing paper P comes into contact with the paper from below, and
Lift. The shaft 23b is provided with a spring member (not shown), and has a structure in which the spring pressure increases when the sheet feeding means 23 is lifted. The printing paper P on the top surface is fed one by one into the printing machine by the rotation of the paper feeding roller 24 of the paper feeding means 23. Paper feed roller 2
Reference numeral 4 includes a scraper roller 24a and a pickup roller 24b that rotate in conjunction with each other.

The paper feed roller 24 is connected to a paper feed clutch 32 via a belt 31. Paper feed clutch 32
The rotation detection sensor 33 is controlled by the control unit 1.
The operation (ON) is performed at the timing of rotation detection (OFF), and the rotational force of the main motor M is transmitted to the paper feed roller 24.

The rotation state (upper limit position) of the paper feeding means 23 is detected by the upper limit sensor 5. The upper limit sensor 5 is constituted by a micro switch as shown. In addition, a photo interrupter integrated with a light emitting and receiving device can be used.
In this case, a detection piece is provided on the upper surface of the support plate 23a, and the detection piece shields the light of the photointerrupter when the sheet feeding means 23 rises, thereby detecting the upper limit position.

The elevating means 28 is composed of rails 28a provided vertically on both sides of the paper feed table 26, and an elevator motor 28b provided on the paper feed table 26. For example, a rack is provided on the rail 28a, and the elevator motor 2
8b is provided with a pinion gear on the rotating shaft. As a result, the paper feed table 26 moves up and down along the rail 28a by the rotation of the elevator motor 28b. Elevator motor 28
b controls the elevation of the paper feed table 26, but in the following description, for convenience, it is assumed that it is raised when ON and stopped (fixed) when OFF.

A paper feed timing roller 30 is provided between the paper feed unit and the printing drum 20 on the paper feed path of the print paper P. This paper feed timing roller 30
Starts rotation at a timing and a rotation speed according to the rotation state of the print drum 20, and causes the print paper P fed from the paper feed unit to be fed to the print drum 20 side at a timing suitable for printing. A paper sensor 7 for detecting the leading end of the printing paper P fed from the paper feeding unit is provided at a position before the paper feeding timing roller 30. The paper sensor 7 is composed of a pair of light emitting and receiving sensors arranged opposite to each other on the transport path, and detects (ON) a period in which light is blocked by the passage of the printing paper P.

A press roller 2 which can contact the print drum 20 with a predetermined pressure at a lower position of the print drum 20.
1 is provided. This press roller is used for the printing drum 2
By passing the printing paper P in a state of contacting the zero side, a printing image corresponding to the image of the stencil sheet is formed on the printing paper P. The printing paper P printed by passing through the printing drum 20 is discharged through the paper discharging unit 22.

The rotation of the printing drum 20 is detected by a rotation detecting sensor 33. In the rotation detection sensor 33, a disk 34 is connected to the rotation shaft of the printing drum 20 via a belt 27. The disk 34 has a slit 34
a is formed. The rotation detection sensor 33 includes a disk 34
It consists of an integrated photo-interrupter that emits and receives light.
It is OFF during the period when the light is shielded by the disk 34, and is ON during the period when the light passes through the slit 34a.

FIG. 3 is a block diagram showing the electrical configuration of the apparatus. The control means 1 controls the entire printing press, and has a paper feed control function as a gist of the present invention.
The control means 1 has a CPU, a ROM, a RAM, and the like.
The control unit 1 receives detection signals from the upper limit sensor 5, the paper-in sensor 7, and the rotation detection sensor 33. Further, control signals for driving the elevator motor 28b, the paper feed clutch 32, and the main motor M are output via the control drive circuits 13a to 13c.

As shown in the timing chart of FIG.
When the rotation detection sensor 33 is turned on (a), the control means 1 turns on the paper feed clutch 32 to feed one print sheet P. The period (T2) during which the rotation detection sensor 33 is turned on, the paper supply clutch 32 operates, and the print paper P is supplied (T2) is always constant with respect to the rotation angle of the print drum 20. Thereafter, (b) the paper-in sensor 7 is turned on.
The feed clutch 7 is turned off after a certain time t2
Then, the feeding of one print sheet P is completed.

(D) When the upper limit sensor 5 is turned off, it is determined that the printing paper P is not at the upper limit position, and (e) the elevator motor 28b is turned on (up) until the printing paper P reaches the upper limit position. This elevator motor 28b is
N. Here, even if (d) the upper limit sensor 5 is OFF, (c) while the paper feed clutch 32 is ON (T2), (e) the operation of the elevator motor 28b (O)
N) is temporarily stopped (OFF).

Next, control processing of the control means 1 will be described with reference to the flowchart of FIG. This control process is executed at regular intervals during the printing operation of the apparatus. First, the state of the upper limit sensor 5 is determined in SP1.
If the upper limit sensor 5 is OFF (SP1-NO), it is determined that the printing paper P is not at the paper feeding position. If the upper limit sensor 5 is ON (SP1-YES), the process proceeds to SP4, where the elevator motor 28b is stopped, and the operation flow exits.

At SP2, the state of the paper feed clutch 32 is determined. If the paper feed clutch 32 is OFF, it is determined that the paper feed operation is not being performed, and the flow shifts to SP3. On the other hand, during the period in which the paper feed clutch 32 is ON (period T2 in FIG. 4C), it is determined that the paper feed operation is being performed, and the process proceeds to SP4 to stop the elevator motor 28b and exit this operation flow.

As described above, even when the upper limit sensor 5 is turned off, the lift of the elevator motor 28b is prohibited while the paper feed clutch 32 is on. As a result, during the paper feeding operation of the printing paper P, the elevation of the elevator motor 28b is prohibited, and the paper feeding pressure between the paper feeding roller 24 and the paper surface of the printing paper P does not change during the paper feeding operation, so that the paper feeding is not performed. Failure can be prevented.

In the above embodiment, the raising of the paper feed table 26 is temporarily stopped based on the operation of the paper feed clutch 32. That is, the period during which the elevation of the elevator motor 28b is prohibited is set to the period during which the upper limit sensor 5 is OFF and the paper feed clutch 32 is ON. The present invention is not limited to this, and a configuration in which the elevation of the paper feed table 26 is temporarily stopped based on the detection of the rotation detection sensor 33 can be adopted. Specifically, a configuration may be adopted in which the lift of the elevator motor 28b is prohibited while the upper limit sensor 5 is OFF and the rotation detection sensor 33 is ON.

The paper feeding clutch 32 is configured to transmit a driving force for feeding the printing paper P from the motor M to the paper feeding roller 24. The driving force is connected in the middle of this transmission path.
It was configured to be cut. However, the present invention is not limited to this. Even when the paper feed roller 24 is directly driven to rotate by an independent paper feed drive unit, the elevator motor 28b is held in a stopped state as described above when the paper feed drive unit is driven. It can be.

The printing paper P is fed from the printing drum 2.
Since it is based on the rotation of 0, it is also possible to adopt a configuration in which the elevation of the paper feed table 26 is temporarily stopped based on the detection of the rotation angle of the print drum 20. Specifically, the position of the printing drum 20 shown in FIG. 1 is set as a reference position (0 °).
Then, while the printing drum 20 rotates in the direction A and is at a rotation position of about 45 ° to about 95 ° shown in FIG.
Is being fed. The rotation angle of the printing drum 20 is detected by angle detection means such as a sensor (not shown). For example, a senna is provided at each of the 45 ° and 95 ° angle positions to detect the angle of the print drum 20. Alternatively, an encoder plate may be provided on the rotating shaft of the printing drum 20, pulses may be detected by a sensor, and the rotation angle of the printing drum 20 may be converted by counting pulses from a reference position. Then, the control unit 1 prohibits the elevator motor 28b from rising during a period in which the rotation angle of the printing drum 20 is about 45 ° to about 95 °. In such a configuration, the same operation and effect as the above embodiment can be obtained.

[0032]

According to the paper feeding apparatus of the present invention, the paper feed tray is controlled to move up and down so that the uppermost surface of the printing paper is always at the upper limit position. Because the paper is kept stopped, it is possible to regulate the cause of the irregular timing of raising the paper feed tray, so that even if the print paper swells during paper feeding, the paper feed pressure of the print paper changes. Without this, it is possible to prevent paper feeding failure. Further, the paper feed control of the present invention is linked with the rotation of the print drum of the stencil printing machine, and holds the elevation of the paper feed table in a stopped state while the print paper is being fed based on the rotation angle of the print drum. A configuration may be adopted, and paper feed during stencil printing can be stabilized.

[Brief description of the drawings]

FIG. 1 is a side view of a stencil printing machine to which a paper feeding device of the present invention is applied.

FIG. 2 is a partial side view showing the embodiment of the sheet feeding device.

FIG. 3 is a block diagram showing an electrical configuration of the device.

FIG. 4 is a timing chart for explaining a sheet feeding operation.

FIG. 5 is a flowchart for explaining paper feed control.

FIG. 6 is a perspective view illustrating a configuration of a sheet feeding device.

[Explanation of symbols]

1 ... control means, 5 ... upper limit sensor, 7 ... paper sensor,
20: print drum, 24: paper feed roller, 26: paper feed table,
28b: elevator motor, 30: timing roller,
32: paper feed clutch; 33: rotation detection sensor; M: main motor; P: printing paper.

Claims (3)

[Claims] A sheet feeder on which printing paper is loaded; elevating means for raising and lowering the paper feeder; A sheet feeding means for feeding a sheet of printing paper one by one to a printing unit, the sheet feeding means having a predetermined timing to rotate the sheet feeding roller at the time of sheet feeding; and A sheet feeding device, comprising: a control unit that prohibits a rise of the sheet feeding table during a period in which the sheet feeding roller is driven to rotate by the sheet feeding unit and holds the sheet feeding table in a stopped state. 2. The paper feed means for rotating the paper feed roller at a predetermined timing interlocked with the rotation of a print drum on which a stencil sheet made into a stencil is mounted, wherein the rotation angle of the print drum is adjusted. An angle detecting unit for detecting, based on a rotation angle of the printing drum detected by the angle detecting unit, the control unit prohibits the paper feed table from rising during a period in which the printing paper is being fed. 2. The paper feeding device according to claim 1, wherein the paper feeding device is held in a stopped state. 3. The printing paper loaded on a paper feeding table is fed one by one from a top surface at a predetermined upper limit position, and the printing paper is fed until the top surface position of the printing paper reaches the upper limit position. A paper feeding method, comprising raising a paper board, and prohibiting the paper feeding table from being raised and holding the paper feeding table in a stopped state while the paper feeding roller is rotationally driven while the paper feeding board is being raised. .