JPH07315596A - Paper feed control method for automatic paper feeding device - Google Patents

Abstract

PURPOSE:To prevent the slip of paper sheets and the erroneous sending of the next paper sheet by detecting the length of a paper sheet in a hopper by means of a paper sheet detecting means and based on the turning amount of a platen and controlling the feeding amount of the paper sheet by means of a paper sheet feeding roller based on the detected paper length. CONSTITUTION:When a paper sheet feeding signal is sent, the turning of a paper feeding roller starts (St.1), feeding a paper sheet. The paper sheet feeding roller continues to turn until paper feeding amount L comes to equal to 11+12 (St.5) and then stops (St.7). In the next step, at the same time when paper sheet length measurement is started (St.9), the turning of a platen is started (St.11). When a paper sheet detecting sensor detects the absence of the paper sheet, the length of the paper sheet is determined from the turning amount of the platen, determining the length A of the paper sheet in a hopper (St.17). The paper sheet feeding roller is turned again to feed the second paper sheet. At that time, the paper sheet feeding amount L by the paper sheet feeding roller is controlled based on the length A of the paper sheet contained in the hopper.

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 automatic paper feed device which automatically feeds cut sheets to a printer.

[0002]

2. Description of the Related Art An automatic paper feeder, such as one that feeds a single sheet to a printer by a paper feed roller driven by a platen driving unit of the printer, or one disclosed in Japanese Utility Model Laid-Open No. 61-18852. There is one in which a sheet feeding device is driven by a driving unit provided in a sheet feeding device to feed a single sheet to a printer. FIG. 3 is a schematic perspective view of a printer equipped with an automatic paper feeder having a driving means, and FIG. 4 is a cross-sectional view of the main parts of the automatic paper feeder and the printer. A cylindrical platen 3 is rotatably provided in the printer 1, and the platen 3 is arranged to face a print head (printing section) 5. As shown in FIG. 4, two pinch rollers 7 are arranged in the circumferential direction of the platen 3.
a and 7b are rotatably abutted on each other, and the pinch rollers 7a and 7b sandwich the sheet 9 between the platen 3 and convey it. A paper detection sensor 11 such as a micro switch is provided on the paper feed side of the pinch roller 7a.
Reference numeral 1 detects the presence / absence of a sheet in the sheet conveyance path by swinging the extended sheet detection lever 13.

As shown in FIG. 3, an automatic paper feeder 15 is mounted near the paper feed port of the printer 1, and the automatic paper feeder 15 is installed.
Has a pair of left and right paper feed rollers 17. Driving means 19 such as a motor provided in the automatic paper feeding device is connected to the paper feeding roller 17, and the driving means 19 is connected to the printer 1 side through a connector 21. Paper feed roller 17
Has a so-called one-way structure (one-way clutch structure) in which the sheets 9 set in the hopper 23 are rotated one by one so as to be fed to the platen 3 and a light load is generated when idling. A sheet guide 25 is provided on the sheet discharge side of the platen 3, and the sheet guide 25 guides the sheet 9 printed on the platen 3 in the sheet discharge direction. A sheet discharge roller 27 that rotates in synchronization with the platen 3 is provided on the sheet discharge side of the sheet guide 25, and the sheet discharge roller 27 conveys the sheet 9 guided by the sheet guide 25 to the stacker 29.

The operation of the automatic sheet feeder and printer thus constructed will be described with reference to FIGS. 5 and 6. FIG. 5 is a time chart showing the signals of the paper feed roller, the platen, and the paper detection sensor, and FIG. 6 is a side view showing the paper feed state. In FIG. 6, l ₁ is the distance from the end of the paper inside the hopper 23 to the contact point between the platen 3 and the pinch roller 7a, and l ₂ is the distance between the pinch rollers 7a and 7b.
When a paper feed signal is output from the printer 1 side to the automatic paper feeder 15, the paper feed roller 17 starts rotating while the platen 3 is stopped (see t _{1 in} FIG. 5), and the hopper 9 feeds the paper one by one. 9 are delivered. In this feeding operation, the sheet 9 operates the sheet detection lever 13 (see t _{2 in} FIG. 5) to cause the platen 3 to move.
The paper 9 is fed to the abutting portion of the pinch roller 7a, and the paper 9 is slightly swollen while the rotation of the platen 3 is stopped so that the leading edge 9a of the paper is surely and straightly sucked. Only ₁ + x is fed, and the feed roller 17 is stopped. Note that x is the amount of slack of the paper 9.

Next, the platen 3 is rotated in the direction in which the sheet 9 is conveyed to the printing section 5 (see t _{3 in} FIG. 5), and the sheet 9 is nipped by the platen 3 and the pinch rollers 7a and 7b and conveyed. To be done. At this time, although the driving of the paper feed roller 17 is stopped, the transport force of the rotation of the platen 3 is significantly larger than the one-way idle load of the paper feed roller 17, so the paper 9 is transported. Then, after the end of the paper 9 is detected by the paper detection lever 13, the platen 3 is rotated by a certain amount, and the next paper 9 is sucked.

[0006]

However, in the conventional paper feeding mechanism including the printer 1 and the automatic paper feeding device 15,
As shown in FIG. 7, the sheet 9 nipped by the pinch rollers 7a is guided while the tip 9a slides along the curved plate guide 3 along the platen 3 and comes into contact with the pinch rollers 7b near the printing section. Therefore, from the sliding / contacting state to the time when the leading edge 9a of the sheet is clamped by the platen 3 and the pinch roller 7b, a load against the sheet conveying force is generated. Then, this sliding / contacting load becomes large.

On the other hand, the paper feed amount L of the paper feed roller 17 is a length (L) obtained by adding the slack amount x to the distance l ₁ to the pinch roller 7a.
= L ₁ + x), and in this case, the paper feed amount L is equal to the hopper 23.
Distance from inner edge of paper to pinch roller 7b l ₁ +1
If it is larger than ₂ (L ≧ l ₁ + l ₂ ), the idling load of the paper feed roller 17 does not occur until the leading edge 9a of the paper is pinched by the pinch roller 7b, but the paper length A is smaller than the distance to the pinch roller 7b. In (A <l ₁ + l ₂ ), the next paper 9 is fed from the paper feed roller 17, two papers 9 are fed into the paper conveyance path, and in the worst case, the paper detection sensor 11 is fed. There was a risk of being detected.

In order to solve such a problem, the paper feed amount L may be set shorter than the paper length L (L <A). In this case, when the paper length A is smaller than the distance to the pinch roller 7b. Although (A <l ₁ + l ₂ ) can be reliably conveyed, the paper length A is larger than the distance to the pinch roller 7b (A> l ₁ + l ₂ ) and the feed amount L is the pinch roller 7b.
If it is smaller than the distance to b (L <l ₁ + l ₂ ), the idling load of the paper feed roller 17 occurs before the leading edge 9a of the paper is pinched by the platen 3 and the pinch roller 7b, and the above-mentioned sliding is caused. In the worst case, slippage may occur between the platen 3 and the sheet 9 in combination with the contact load, and reliable conveyance may not be possible. This is because it is very difficult to keep the slack amount x of the paper constant when using the paper 9 of various lengths. The present invention has been made in view of the above circumstances, and provides a sheet feeding control method for an automatic sheet feeder that can prevent slipping of a sheet and erroneous feeding of the next sheet when sheets of various lengths are used. ,
Therefore, it is intended to improve the stability of sheet conveyance.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, a method of controlling paper feeding of an automatic paper feeding apparatus according to the present invention is such that a pair of pinch rollers are arranged in contact with each other in a cylindrical platen circumferential direction. In addition, an automatic paper feeder equipped with a paper feed roller with a one-way clutch structure that feeds the paper stored in the hopper to the printer one by one is installed in the printer with paper detection means in the paper transport path. In the paper feed control method of the automatic paper feeder in the case of performing the above, the paper length in the hopper is detected by the rotation amount of the paper detection means and the platen, and the paper feed amount by the paper feed roller is based on the detected paper length. It is characterized by controlling.

[0010]

When the length of the paper accommodated in the automatic paper feeding device is detected by the paper detecting means and the length of the paper is shorter than the distance from the paper feeding roller to the pinch roller in the vicinity of the printing portion, the automatic paper feeding device is operated. The paper feed amount is controlled to be equal to the paper length, the paper feed roller does not rotate more than necessary, and erroneous feeding of the second paper is eliminated. On the other hand, when the paper length is longer than the distance from the paper feed roller to the pinch roller near the printing unit, the amount of paper fed by the automatic paper feeder is shorter than the paper length and the pinch roller near the printing unit is located near the printing unit. Is set to a value longer than the distance up to the distance between the platen and the pinch roller near the printing unit, and the idling load of the paper feed roller does not occur before the tip of the paper is pinched and slippage does not occur between the platen and paper. .

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a paper feed control method for an automatic paper feeder according to the present invention will be described in detail below with reference to a flow chart. 1 and 2 are flowcharts showing the procedure of the paper feed control method of the present invention, where A in FIG. 1 is connected to A in FIG. The same members as those shown in FIGS. 3, 4, and 6 are designated by the same reference numerals, and a duplicate description will be omitted. The paper feed control method of the present embodiment uses the paper detection means (paper detection sensor 11 and paper detection lever 13) provided in the printer 1 to determine the length of the paper 9 accommodated in the automatic paper feeder 15. This is for detecting and controlling the sheet feed amount of the sheet feed roller 17 of the automatic sheet feeder 15 according to the sheet length.

As a procedure of the paper feeding control method, first, when a paper feeding signal is sent from the printer 1 side to the automatic paper feeding device 15, the platen 3 is stopped and the feeding roller 17 starts to rotate ( In step 1), the sheets 9 are fed one by one from the hopper 23. At this time, the leading edge 9a of the sheet 9 is the sheet detection lever 13
Is operated (st. 3), and the platen 3 and the pinch roller 7a are guided to the contact portion. Further, the paper feed roller 17 is rotated (st. 5) until the paper feed amount L = l ₁ + l ₂ and then stopped (st. 7).

Next, the measurement of the paper length A is started (st. 9).
At the same time, the rotation of the platen 3 is started (st. 11). The printing operation and the sheet conveyance are repeated with the rotation of the platen 3 (st. 13), and the measurement, printing, and conveyance operations are continued until the sheet detection sensor 11 detects the absence of the sheet (st. 1).
Five). Then, when the absence of paper is detected, the paper length A is obtained from the rotation amount of the platen 3, and the paper length A of the paper 9 currently accommodated in the hopper 23 is determined (st. 1).
7). Printed paper 9 after paper length A is determined (st.17)
Is discharged by the paper discharge roller 27 (st. 19), the paper feed roller 17 is rotated again (st. 21), and the second sheet 9 is fed.

At this time, the paper feed amount L of the paper feed roller 17 is rotationally controlled based on the paper length A accommodated in the hopper 23 (st. 23). That is, when the paper length A is larger than the distance to the pinch roller 7b (A> l ₁ + l ₂ ), A> L ≧
The paper feed roller 17 is rotated by a length such that the relationship of l ₁ + l ₂ is established (st. 25), and paper is fed by such a size that the leading edge 9a of the paper surely reaches the abutting portion of the platen 3 and the pinch roller 7b. . On the other hand, when the paper length A is smaller than the distance to the pinch roller 7b (A <l ₁ + l ₂ ), the paper feed roller 17 is rotated by the same feed amount (L = A) as the paper length A (st. 27), the paper 9 is surely discharged from the hopper 23, and the idling load of the paper feed roller 17 is removed. Then, the paper feed roller 17 is stopped (st. 29), the platen 3 is further rotated (st. 31), printing and paper discharge operation (st. 33) are performed, and then the second paper 9 is discharged. Returning to the operation (st. 19), the third sheet 9 is fed by the rotation of the sheet feeding roller 17 (st. 21) again, and thereafter, the same operation as the second sheet is repeated.

In the above-described paper feed control method, the paper detection means detects the length of the paper 9 accommodated in the automatic paper feeder 15, and the paper feed amount of the paper feed roller 17 is controlled according to the paper length. It That is, when the paper length A is shorter than the distance l ₁ + l ₂ from the paper feed roller 17 to the pinch roller 7b near the printing section (A <l ₁ + l ₂ ), the paper feed amount L of the automatic paper feed device 15 is equal to the paper feed amount L. The length is controlled to be equal to A (L = A), the paper feed roller 17 is prevented from rotating more than necessary, and the second paper 9 is not fed. On the other hand, the paper length A is the distance l ₁ from the paper feed roller 17 to the pinch roller 7b near the printing unit.
When it is longer than + l ₂ (A> l ₁ + l ₂ ), the amount L of paper fed by the automatic paper feeder 15 is controlled to an amount that establishes the relationship of A> L ≧ l ₁ + l ₂ . That is, the sheet feed amount L is set to be shorter than the sheet length and longer than the distance from the sheet feed roller 17 to the pinch roller 7b. As a result, the idling load of the paper feed roller 17 does not occur before the leading edge 9a of the paper is pinched by the platen 3 and the pinch roller 7b, and slippage does not occur between the platen 3 and the paper 9.

As described above, according to the above-described paper feed control method, since the paper feed amount of the paper feed roller 17 is controlled according to the paper length, it is possible to prevent the second paper from entering the paper transport route. This can be surely prevented, and the slip between the platen and the sheet due to the idling load of the sheet feeding roller 17 can be prevented, so that the sheet can be always conveyed stably. In addition,
In the present invention, the case where the automatic paper feeding device 15 is provided with the paper feeding drive means has been described.
As shown in No. 0, the same effect can be obtained even if the sheet feeding means of the automatic sheet feeding device is driven by rotating the platen of the printer in the reverse direction.

[0017]

As described above in detail, according to the paper feed control method of the automatic paper feeder according to the present invention, the paper is housed in the automatic paper feeder according to the paper detection signal from the printer and the rotation amount of the platen. Since the length of each sheet is detected and the feeding amount of the second and subsequent sheets in the hopper is controlled based on the sheet length, it is possible to prevent erroneous feeding of two sheets at the same time in the sheet conveying path. At the same time, slip between the platen and the paper due to the idling load of the paper feed roller can be prevented, and the stability of paper conveyance can be significantly improved when using papers of various lengths.

[Brief description of drawings]

FIG. 1 is a flowchart showing a procedure of a paper feed control method according to the present invention.

FIG. 2 is a flowchart showing a procedure of a paper feed control method of the present invention.

FIG. 3 is a schematic perspective view of a printer equipped with an automatic paper feeder having a driving unit.

FIG. 4 is a cross-sectional view of main parts of an automatic paper feeder and a printer.

FIG. 5 is a time chart of signals of a paper feed roller, a platen, and a paper detection sensor.

FIG. 6 is a side view showing a sheet feeding state.

FIG. 7 is an enlarged view of a paper guide unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Printer 3 Platens 7a, 7b Pinch roller 9 Paper 11 Paper detection sensor (paper detection means) 13 Paper detection lever (paper detection means) 15 Automatic paper feeder 17 Paper feed roller 23 Hopper

Claims (3)

[Claims] 1. A printer in which a pair of pinch rollers are disposed in contact with a cylindrical platen in the circumferential direction and a paper detection means is provided in a paper transport path, and one paper stored in a hopper is used. In the paper feed control method of the automatic paper feed device, in which a paper feed roller having a one-way clutch structure for feeding paper to the printer one by one is installed, the rotation amount of the paper detection means and the platen A paper feed control method for an automatic paper feeder, wherein the paper length in the hopper is detected by, and the amount of paper fed by the paper feed roller is controlled based on the detected paper length. 2. When the paper length detected by the paper detection means is shorter than the distance from the paper feed roller to the pinch roller near the printing unit, the paper feed amount of the paper feed roller is equal to the paper length. 2. The paper feed control method for an automatic paper feed device according to claim 1, wherein the paper feed control method is set to the length. 3. The paper feed amount of the paper feed roller is shorter than the paper length when the paper length detected by the paper detection means is longer than the distance from the paper feed roller to the pinch roller near the printing unit. 2. The paper feed control method for an automatic paper feeder according to claim 1, wherein the amount is set to be longer than the distance from the paper feed roller to the pinch roller near the printing unit.