JPH0753463B2 - Printer controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] In order to smoothly perform a reverse line feed operation without causing a paper jam even when printing on the back side of the paper, the paper length measured in parallel with the printing at the time of the front side printing. And grasp the end position of the paper through the line feed count when printing on the back side,
If the end of the paper exists near the path branch point, a normal line feed is made continuous until the end of the paper passes through the path branch point before the specified reverse line feed operation is performed. It is designed to control line breaks.

[Industrial application field]

The present invention relates to a control method for a printer having a sheet reversing function, and more particularly to a printer control device capable of smoothly performing a reverse line feed during printing on the back surface after printing the front surface of the paper.

[Prior Art] In recent years, printers forming a part of an information processing apparatus have been increasingly used, which have a function of printing not only on the front surface of paper but also on the back surface.

FIG. 8 is a principal part explanatory view showing an example of a conventional printer, and FIG. 9 is a flowchart of sheet detection in the conventional example.

In FIG. 8, 1 is a print head, 2 is a platen, paper (not shown) and ink ribbon are inserted between the print head 1 and the platen 2, and a CPU (not shown) is also provided.
The print head 1 is driven in response to a command from the printer to print.

A paper detection sensor 3 detects the leading edge and the trailing edge of the paper when printing the front surface of the paper, and counts the presence and absence of the paper by counting the number of feed pulses and counting the presence and absence of the paper (both figures Control (not shown). Reference numeral 4 is a paper feed roller, 5 is a paper inlet / outlet port, 6 is a paper guide, and 7 is a guide drum, which together with the paper guide 6 serve as a guide for reversing the paper. A paper detection sensor 8 detects the leading edge and the trailing edge of the paper when the paper is reversed, and controls the paper presence count and the paper absence count similarly to the paper detection sensor 3.

A is a printing unit, which is a print head 1, a platen 2, a paper detection sensor
3, a paper feed roller 4, and a paper detection sensor 8.

Further, B is a paper reversing portion, which is composed of a paper feed roller 4, a paper guide 6, and a guide drum 7.

Regarding the printer having such a configuration, the paper feeding process will be described with reference to FIG.

Line feed (line feed) from the main unit (not shown)
Is executed (91).

Based on this execution command, the excitation phase of the pulse motor that feeds the paper is switched to start feeding the paper (92).

When the leading edge of the paper is detected by the paper detection sensor 3, the first position according to the format set by the main body device from that position is detected.
When the paper is fed to the line print position, printing of the first line is started (93).

The paper out count is cleared by the ON signal of the paper detection sensor 3 (94).

When the paper detection sensor 3 cannot detect the paper,
Count up the paperless count (95).

Compare if the out-of-paper count is greater than the defined out-of-paper count (96).

If the out-of-paper count is greater than the specified out-of-paper count, an out-of-paper process is performed (97).

Clear out-of-paper count (94) and if the out-of-paper count is not greater than the specified out-of-paper count, return to the original and repeat the next execution (98).

After printing the front surface of the paper, the paper is reversed by the reversing unit B, and the leading edge of the paper is detected by the paper detection sensor 8. The subsequent operation is exactly the same as when printing the front surface of the paper.

[Problems to be Solved by the Invention] Printing on paper is performed by repeating a line feed each time the print head 1 runs one line. This line feed is not limited to a normal line feed, but a command or an offline switch, etc. There is a case that the line break is done by. Even if a reverse line feed is performed during the front side printing, no particular inconvenience occurs, but when the back side of the sheet is located near the passage branch point 9 of the reversing portion B shown in FIG. 8 during the back side printing, There is a problem in that the paper does not move back smoothly due to the above-mentioned reverse line feed and a so-called jam occurs. In order to solve such a problem, in the conventional printer, a passage switching guide 10 is provided at the passage branch point 9. However, by providing such a path switching guide 10, the structure in the vicinity of the narrow path branch point 9 is complicated, maintenance and inspection are complicated, and paper jam may occur depending on the rotation direction of the paper feed roller 4. There is a problem that it cannot be completely prevented. In addition, printers of recent years are required to have more severe high speed and reliability, and these requirements cannot be satisfied by the above conventional apparatus, and a printer having a simple structure and high reliability is desired. It is rare.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems existing in the above-mentioned conventional printers, and particularly to provide a printer control device that can smoothly perform a back feed when printing on the back side.

[Means for Solving the Problems]

In order to achieve the above object, in the present invention, in a control device of a printer having a paper reversing function, a paper detecting means for detecting the presence or absence of the leading edge of the paper, and a paper detecting means at the time of printing on the surface of the paper. Counts the number of feed pulses from when the presence of paper is detected to when the absence of paper is detected,
A means for storing the number of pulses corresponding to the paper length is provided, and the number of pulses corresponding to the distance from the paper detecting means to the trailing edge of the paper and the distance to the paper branch point when performing a reverse line feed at the time of printing on the back surface of the paper x And L are compared, and if L-α ≤ x ≤ L + α (α is a constant), the paper is fed with {x- (L-α)} pulse number of normal lines before the predetermined reverse line feed, and then this positive line feed is performed. We adopted the technical means of adding a line feed and adding a control unit that controls the line feed back.

FIG. 1 is an explanatory view of the main part of the printer of the present invention, and the same parts are designated by the same reference numerals as those shown in FIG. First
In the figure, 11 is a sheet, which shows a state in which after the printing on the front side is completed, it is reversed in the reversing section B, is fed in the direction of the arrow, and the back side is printed. x is the distance from the paper detection sensor 3 to the rear end of the paper 11, and L is the distance from the paper detection sensor 3 to the passage branch point 9 of the reversing portion B.

FIG. 2 is a flow chart showing the basic principle of the present invention. First, when a reverse line feed start command 21 is issued in the back side printing state as shown in FIG. 1, the relationship between the position of the trailing edge of the sheet 11 and the passage branch point 9 in FIG. 1 is checked (22). That is, the constant α is set to a predetermined value, and x> L
When + α or x <L−α, the line feed is performed (23) for the designated amount and the process is terminated (26). On the other hand, L-α ≦ x ≦
In the case of L + α, a normal line feed is performed for x− (L−α) (2
Four). That is, in FIG. 1, the paper 11 is fed forward in the direction of the arrow, and the rear end of the paper 11 is positioned to the right of the passage branch point 9. Next, the specified line feed is added to the above normal line feed to make a line feed back (25) and end (26).

[Work]

With the above configuration, when a reverse line feed is made during printing on the back side, a specified amount of reverse line feed can be smoothly executed without causing a paper jam.

〔Example〕

FIG. 3 is an explanatory view of essential parts showing an embodiment of the present invention, and the same parts are designated by the same reference numerals as those in FIGS. 1 and 8. In FIG. 3, reference numeral 12 denotes a guide, which is provided substantially above the guide drum 7 in the reversing portion B, is rotatable by, for example, a solenoid drive, and is capable of reversing / discharging the sheet. 9a and 9b are paper paths, respectively, which are provided above and below the path branch point 9.

FIG. 4 is a block diagram of an embodiment of the present invention.

In FIG. 4, reference numeral 40 is a CPU, 41 is a main unit, and both are connected via an interface 42. 43 is a data storage RAM having a count with paper and a count without paper,
Reference numeral 44 is a program storage ROM that stores a printer control program or characters, and 45 is a line buffer that can store printing for one line. A sensor driver 46 drives the paper detection sensor 3 shown in FIG. 3 and other sensors (not shown). A motor driver 47 drives a drive source (not shown) such as a motor or a solenoid mounted on the printing unit A and the reversing unit B shown in FIG. A hammer driver 48 drives the hammer of the print head 1.

FIGS. 5 (a) to 5 (c) are explanatory views of the reverse line feed control in the embodiment of the present invention, respectively, showing the state of back surface printing, and the same portions are denoted by the same reference numerals as those in FIG. .

First, in FIG. 5A, the trailing edge of the sheet 11 is the sheet path 9a.
And the paper feed roller 4 is completely engaged,
In the case of reverse line feed in this state, the platen 2 and the guide drum 7 may be rotated counterclockwise as shown by arrows.

Next, FIG. 5B shows a state in which the trailing edge of the sheet 11 is near the passage branch point 9. If the line feed is reversed in this state, the rear end of the paper 11 may come into contact with the passage branch point 9 or the paper feed roller 4 to cause so-called paper jam, and damage the front-printed paper 11. Therefore, first, the platen 2 and the guide drum 7 are rotated clockwise as indicated by the solid line arrow so that the rear end of the sheet 11 completely passes through the passage branch point 9. As a result, the sheet 11 becomes substantially horizontal as shown in FIG. 5 (c) described later. Next, the platen 2 and the guide drum 7 are rotated counterclockwise and clockwise, respectively, as indicated by broken line arrows, and the amount of reverse line feed is added to the paper feed amount to perform reverse line feed. In this case, since the trailing edge of the sheet 11 enters the sheet passage 9b side, the sheet jam does not occur.

FIG. 5C shows a state in which the trailing edge of the sheet 11 has completely passed through the passage branch point 9. In order to reverse the line feed at this position, the platen 2 may be rotated counterclockwise and the guide drum 7 may be rotated clockwise as indicated by the arrow.

FIG. 6 is a general explanatory view of the reverse line feed control in the embodiment of the present invention, and the same portions are the same as those in FIGS. 1 and 5 (a).
The same reference numerals as those in FIGS. In FIG. 6, α is a constant, but the value of the constant α is determined in consideration of the state of interference with the sheet 11 in the vicinity of the branch point 9 of the passage. The numbers in the platen 2 and the guide drum 7 or the directions of rotation are shown.

FIG. 7 is a flow chart of an embodiment of the present invention, and the flow in the case of a reverse line feed will be described together with FIG. When a reverse line feed is started (71) in response to a command from the main unit 41 in FIG. 4, the rear end position of the paper 11 and the passage branch point 9
The relative position is compared with. That is, the relationship between the distances x and L (hereinafter simply referred to as x, L) from the paper detection sensor 3 to the rear end of the paper 11 and the passage branch point is x> L.
If it is + α (72), the rotation direction of the printing unit motor is designated as (73), the rotation direction of the reversing unit motor is designated as (74), and the designated reverse line feed amount pulse is rotated (75) to reverse. A line break is made (76). In this case, in FIG. 6, the trailing edge of the paper 11 is retracted on the paper passage 9a side.

Next, if x <L-α (77), the rotation direction of the printing unit motor is designated as (78), the rotation direction of the reversing unit motor is designated as (79), and the designated line feed amount pulse is rotated ( 80)
And perform a new line (76). In this case, the paper in FIG.
The trailing end of the sheet 11 is located on the right side of the passage branch point 9, and the sheet 11 enters the sheet passage 9b side by the above-described reverse line feed.

Next, when neither of x> L + α (72) or x <L-α (77) is satisfied, that is, when L−α ≦ x ≦ L + α, the trailing edge of the sheet 11 in FIG. There is a range from the branch point 9 to ± α, and if a reverse line feed is executed as it is, a paper jam may occur. Therefore, in this case, as shown in FIG. 7, the rotation direction of the printing unit motor is designated as (81), the rotation direction of the reversing unit motor is designated as (82), and x- (L-α) is designated. Store in memory (8
3), rotate by the amount of this memory (84). That is, in FIG. 6, the rear end of the sheet 11 is fed from the passage branch point 9 to a distance of α or more. Next, in Fig. 7, the rotation direction of the printing motor is designated as (85), and the rotation direction of the reversing motor is designated as (86), and the specified reverse line feed amount + memory (see 83) is stored in the memory. (87) and by rotating (88) this memory, a predetermined reverse line feed can be performed (76). That is, in FIG. 6, since the paper 11 is in a substantially horizontal state, even if the paper 11 advances to the left due to a reverse line feed, it does not enter the paper passage 9b and cause a paper jam.

〔The invention's effect〕

Since the present invention has the configuration and operation as described above,
It is possible to smoothly perform the reverse line feed at the time of printing on the back side without causing a paper jam and improve the reliability. Moreover, unlike the conventional one, there is no need to install a passage switching guide at the passage branch point, and maintenance and inspection is extremely easy.

[Brief description of drawings]

FIG. 1 is an explanatory view of essential parts of a printer of the present invention, FIG. 2 is a flow chart showing the basic principle of the present invention, FIG. 3 is an explanatory view of essential parts of an embodiment of the present invention, and FIG. 5 is a block diagram of the embodiment, FIGS. 5 (a) to 5 (c) are explanatory views of the reverse line feed control in the embodiment of the present invention, and FIG. 6 is a general explanatory diagram of the reverse line feed control in the embodiment of the present invention. FIG. 7 is a flow chart of an embodiment of the present invention, FIG. 8 is an explanatory view of main parts of an example of a conventional printer, and FIG. 9 is a flow chart of paper detection in the conventional example. A: print part, B: reversal part, 9: passage branch point, 11: paper.

Claims (1)

[Claims] 1. A printer control device having a paper reversing function, a paper detecting means for detecting the presence or absence of paper at the leading edge of the paper, and a paper detecting means for detecting the presence of paper at the time of printing on the front surface of the paper. Count the number of feed pulses until the absence is detected,
A means for storing the number of pulses corresponding to the paper length is provided, and the number of pulses corresponding to the distance from the paper detection means to the trailing edge of the paper and the distance to the paper branch point, respectively, when performing a reverse line feed on the back surface of the paper x And L are compared, and if L-α ≤ x ≤ L + α (α is a constant), the paper is fed with {x- (L-α)} pulse number of normal lines before the predetermined reverse line feed, and then this positive line feed is performed. A printer control device comprising a control unit for controlling a line feed after adding a line feed.