JPH05338223A - Thermal serial printer - Google Patents

Abstract

PURPOSE:To prevent staining with a printing residue at a new line in bidirectional printing by driving a print head for a short time in the reverse direction after printing data for one line and starting paper feeding again. CONSTITUTION:A cycle of bidirectional printing comprises eight steps: (1) A carriage, moving in the normal direction, prints data for one line, leaving a printing residue of colored ink,. etc., deposited at the recess of a thermal head top. (2) After printing, the carriage overruns in the same direction. (3) The carriage moves for a short time in the reverse direction to disperse and remove the printing residue. (4) Paper feeding starts. (5) Printing in the reverse direction starts. The steps from (5) to (7) are similar to the steps from (1) to (3) except for the directions (normal and reverse) of the carriage movement. (8) Paper feeding is carried out as in the step (4).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called thermal serial printer which prints on thermal paper by moving a print head in a direction perpendicular to the paper feed direction.

[0002]

2. Description of the Related Art In recent years, small-sized thermal serial printers have been increasingly used in information technology, and the demand for new fields such as palmtop type computers and bank terminals has increased from special fields such as conventional registers and measuring instruments. Higher quality and higher printing speed are required.

A conventional thermal serial printer will be described below. 5 and 6 show the structure of a conventional thermal serial printer and how the head moves.

In the figure, reference numeral 1 is a thin film type thermal head. Reference numeral 2 denotes a carriage that holds the thermal head 1, and printing can be performed by energizing the thermal head 1 while moving it left and right. Reference numeral 3 denotes a paper feed motor, which rotates the roller 4 that presses the recording paper 6 to rotate the recording paper 6
Paper feed operation. A platen 5 serves as a receiver of the recording paper 6 when the thermal head 1 is pressed against the recording paper 6.

The operation of the thermal serial printer configured as described above will be described below with reference to FIG.

First, data is printed while the carriage 2 holding the thermal head 1 moves in the forward direction. After the printing is completed, the paper is slightly overrun in the same direction and stopped, and then the paper feed motor 3 feeds one line of paper. After the paper feed is completed, the carriage 2 moves in the opposite direction while printing. After printing one line of data, bidirectional printing is performed by repeating the same operation. Bidirectional printing is
This is an efficient driving method that can shorten the printing time compared to printing in only one direction.

[0007]

In the conventional control method described above, printing is performed while moving while the front end of the thin-film thermal head 1 is in contact with the surface of the recording paper 6, and therefore, FIG.
As shown in (c), printing residue 8 such as colored ink 7 adheres to the concave portion at the tip of the head, and during bidirectional printing, the thermal head 1 and the recording paper 6 are fed while being in pressure contact. As a result, the printing scraps 8 are scraped off and stains 9 as shown in FIG. 8 occur in the paper feeding direction of the recording paper 6.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a thermal serial printer which is free from stains due to printing dust at the time of line feed in a bidirectional printing operation.

[0009]

In order to achieve this object, the thermal serial printer of the present invention is configured so that after printing one line of data, the carriage is slightly moved in the opposite direction, or while the paper is being fed. It has operation control of performing an operation.

[0010]

With this structure, the print dust accumulated on the side opposite to the print direction of the concave portion of the head tip is diffused or removed partially or entirely by a slight movement of the carriage in the reverse direction, and the head is pressed against the recording paper. Even if the paper is fed in this state, it is possible to reduce or eliminate the stain due to the adherence of the printing dust on the surface of the recording paper to an inconspicuous level.

[0011]

【Example】

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings. 1, 2 and 3 show the operation control of the thermal serial printer in one embodiment of the present invention, and the operations (1) to (8) in FIG. 1 correspond to each drawing. First, as (1), data for one line is printed while the carriage moves in the forward direction. At this time, as shown in FIG. 4 (a), a print residue 8 such as colored ink accumulates in the concave portion at the tip of the thermal head 1.
After printing is completed, the carriage is overrun in the same direction as (2). Subsequently, as shown in FIGS. 4B and 4C, the carriage (3) is slightly moved in the opposite direction, so that the print dust 8 is diffused and eliminated. Thereafter, as (4), the paper feeding operation is performed, and printing in the reverse direction of (5) is started. (5) to (7) are the same operations as (1) to (3), although there are forward and reverse movement directions. After this,
By carrying out the paper feed of (8) (same as (4)), one cycle of the bidirectional printing operation is completed.

As described above, according to the present embodiment, after the one-line printing (1) is completed and before the paper feeding operation (4), the overrun operation (2) is performed in the forward direction, and then slightly reversely. By providing the operation of moving (3), it is possible to make the dirt caused by the printing dust when the paper is fed inconspicuous or at the same time, and to correct the printing start position in the opposite direction (3).
It is also possible to substitute a slight movement in the opposite direction.

In this embodiment, the overrun operation of (2) is performed in order to simultaneously realize the correction of the print start position in the opposite direction. However, if it is between (1) and (5), It may or may not be in any position. The effect of the present invention can be realized by the operation (3) between (1) and (4). Also in this sense, the movement in the slightly opposite direction and the paper feeding operation, that is, (3) and (4) or (7)
Needless to say, and (8) can be performed at the same time.
By reducing the operation loss, higher speed can be realized.

[0014]

As described above, according to the present invention, after the printing of one line of data is completed, the head is moved slightly in the opposite direction, and then the paper feeding operation is performed so that the head and the recording paper are kept in pressure contact with each other. Even if the feeding operation is performed, it is possible to realize excellent print quality that can prevent the occurrence of stains when the paper is fed.

[Brief description of drawings]

FIG. 1 is a timing chart for explaining an operation of a thermal serial printer according to an embodiment of the present invention.

FIG. 2 is an operation sequence explanatory diagram for explaining the operation of the thermal serial printer in the embodiment.

FIG. 3 is an operation flowchart for explaining an operation of the thermal serial printer in the embodiment.

4 (a) to (c) are enlarged views showing the action of the present invention.

FIG. 5 is a sectional view showing the structure of a conventional thermal serial printer.

FIG. 6 is an operation sequence explanatory diagram of a conventional thermal serial printer.

7A to 7C are enlarged views for explaining the problems in the conventional thermal serial printer.

FIG. 8 is an explanatory diagram showing a state of dirt, which is a problem in the conventional thermal serial printer.

[Explanation of symbols]

 1 Thermal Head 2 Carriage 3 Paper Feed Motor 4 Roller Shaft 5 Platen 6 Recording Paper 7 Ink 8 Printing Waste 9 Dirt

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical display location B41J 19/18 Z 9212-2C (72) Inventor Toshio Tanaka 1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric Sangyo Co., Ltd.

Claims (2)

[Claims] 1. A thermal serial printer configured to perform a paper feeding operation after a print head is slightly moved in the opposite direction after printing one line of data. 2. The thermal serial printer according to claim 1, wherein the paper feeding operation is performed while slightly moving the print head in the opposite direction.