JPS6018376A - Reverse feeding of paper in printer - Google Patents

Abstract

PURPOSE:To enable to reversely feed a paper easily and with high accuracy, by forwadly feeding the paper by one line after reversely feeding the paper by a predetermined number of lines pluse one additional line. CONSTITUTION:When reversely feeding a recording paper by a predetermined number (n) of lines, a command for reversely feeding the paper by n+1 lines is supplied through a CPU or the like, and a stepping motor for a feeding roller is controlled. After the paper is reversely fed by n+1 lines, it is fed forwards by one line through the CPU. Accordingly, backlash is securely avoided, and the recording paper can be reversely fed easily and with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for reverse feeding paper in a printer such as a terminal printer that reversely feeds paper.

When printing graphics, making corrections or additions, or using a terminal printer as a plotter, it is necessary to pack-feed the paper, that is, to feed it in the opposite direction.

Normally, printers use a stepping motor to feed paper, and convert the rotation of the rotor one step at a time to feed the paper line by line through an appropriate deceleration mechanism. In this case, an error in paper feeding occurs due to the backlash of each part of the deceleration mechanism compared to the case of normal feeding, that is, forward feeding, making it impossible to print accurate graphics or blocks.

Since the pitch between the needles of the print head of a normal dot printer is about 0.35 mm, the above-mentioned error in forward and reverse paper feeding must be kept to less than about 0.1 mm. Increasing the accuracy to suppress this requires a complicated and expensive mechanism, and also increases the feed torque, requires a large amount of power, and places a heavy burden on the stepping morph.

The object of the present invention is to eliminate the above-mentioned drawbacks and to provide a very simple and highly accurate method for reversing paper in a printer.

The paper feeding method in a printer according to the present invention is characterized by: a paper feed drive that performs a predetermined rotation according to a command from a command circuit in order to feed paper in the reverse direction for a predetermined number of lines; n as a command to reverse feed n lines to the means.
The object of the present invention is to give a command to give a backward feed for at least one extra line in addition to the number of lines, followed by a forward feed for the number of extra lines.

With this structure, even if there is backlash in the speed reduction mechanism, etc., when backward feeding a predetermined number of digits, it is always possible to perform forward feeding for the required number of rows after performing an extra backward feeding. This makes it possible to reliably eliminate backlash and always perform reverse feeding to the correct position.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

Figure 1 shows the method of reverse paper feeding in a conventional printer. When performing pack feed for n1 lines, specify n=n and perform pack feed (B, FEED) for 1 line, followed by le=n.
-1 reverse feed loop is performed 71. Reverse feed ends when =0. Therefore, backlash remains in the printer, and paper feeding errors cannot be eliminated.

FIG. 2 shows the method of reverse paper feeding according to the present invention, in which n rows (
7) When performing pack feed, specify rule +1, perform a backward feed loop of the rule following one line of pack feed (B, FEED), perform backward feed of 1,000 lines at route 0, and then 1 A line feed, that is, a forward feed (F, FEED) of the rows is performed to complete the n-row inverse meandering in which backlash has been completely eliminated. In this case, the number of reverse feed lines to be added may not be one, it may be two or more, and the number of forward feed lines for the reverse feed profit may be the same.

FIG. 3 is a drawing showing the operation of a stepping motor in a printer, and the stepping morphs are, for example, coils Ll, L2, . L3. L4-f: Consists of a stator S provided with salient poles Pi, P2, P3, P4, and a rotor R having a large number of gear-shaped poles P that sequentially cooperate with these salient poles; The amount of rotation for each predetermined step causes the paper to be sent line by line in the X forward or reverse direction via a deceleration mechanism (not shown).

The drive of the rotor R starts from the stopped state shown in FIG.
When driving pulses with a predetermined pulse width are sequentially applied to L4..., the pulse is applied to the coil L4, and the @P of the rotor R near the pole P4 of the stake S is attracted and rotates counterclockwise. Then, the state shown in Fig. 3 (B) is reached, and then when a pulse is given to the coil L3, it rotates further counterclockwise and becomes the state shown in Fig. 3 (C), and then a pulse is given to the coil L1. Then rotate further counterclockwise until it reaches Figure 3 (
In state D), the rotor R performs a predetermined rotation by applying pulses a predetermined number of times.

Pulse to coil L2 → L3 → L4 → Ll...
If given in this order, it will rotate in the opposite direction.

FIG. 4 shows a command circuit that applies drive pulses to each coil Ll, L2, etc. in order to carry out the required paper feeding according to the present invention, and sends the command circuit to the central processing unit CPS via the data bus D'B. An interface I10 is connected to which outputs to coils Ll, L2k, L3 and L4 which define the application order and number of driving pulses required for a predetermined paper feed are output from the interface I10. Each of these outputs is connected to a resistor R1.

RZ, R3, R4 and transistors Tr1. Tr3
Through Tr3゜Tr4, backflow prevention diode DI,
D2.

D3. Coil L1 provided with D+. L2, L3
is added to give the rotor IRIc a predetermined rotation.

The feature of the present invention is that when a reverse feed of n lines is specified, the output of the interface I10 is first a reverse feed of n lines plus at least one stroke, and then a forward feed of the extra number of lines. The advantage of this is that it is set to perform n-line back-transfer without backlash at all times.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a method for reverse paper feeding in a conventional printer. FIG. 2 is a block diagram showing the reverse feed Sibra method according to the present invention. FIG. 3 is an explanatory diagram of the operation of a stepping motor suitable for use in the present invention. FIG. 4 is a circuit diagram showing a stepping motor drive command circuit according to the present invention. CPU...Central processing unit I10...Interfaces LL, LZ, L3. L4... Coil P...
... Pole Pl, P2 of loaf R. P3. P4... Salient pole R of stake S... Loaf S... Stator Trl, Tr2. Tr3. Tr4. -) Ranjistor Patent Applicant Copal Co., Ltd. Procedural Amendment August 9, 1982 1. Behind the wheel of a car 1988 Patent Application No. 124754 2. Name of the invention Method for reverse feeding paper in a printer 3.Relationship with the 211 amendments Patent application office: 2-16-20 Shimura, Karuhashi-ku, Tokyo Name: Cup (
Name) (+22) Copal nq Co., Ltd. −

Claims (1)

[Claims] In order to feed paper in the reverse direction by a predetermined number of lines, n
A paper sheet in a printer characterized in that, as a command for reversely feeding lines, a command is given to reversely feed at least one extra line in addition to n lines, followed by forward feeding for the extra number of lines. Reverse feed method.