JP3185824B2 - Serial printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a serial printer, and more particularly to a configuration of a scanning mechanism of a recording head.

[0002]

2. Description of the Related Art As a conventional serial printer, a recording head capable of selectively forming a plurality of dots, typically 7 to 48, performs recording by scanning a recording area while reciprocating on a recording sheet. Methods are known. As the recording principle, an ink jet system, an impact dot system, and the like are known. As the printing operation, there are known two methods, a method of performing printing only in one-way moving operation (one-way printing) and a method of performing printing in both directions of moving operation (bi-directional printing) in reciprocating scanning. The recording paper stops during the recording operation of the recording head,
In the bidirectional printing system, when the movement direction of the reciprocating operation of the recording head is reversed, and in the one-way printing system, at the time of the returning operation of the recording head, the recording head is transported by a predetermined amount in a direction orthogonal to the scanning direction.

FIG. 6 shows the relationship between the scanning speed of the recording head, the change over time in the moving speed of the recording paper, and the driving signal of the recording head. FIG. 6A shows the case of bidirectional printing, and FIG. 6B shows the case of unidirectional printing.

[0004]

In the above-mentioned prior art serial printer, since the recording paper is conveyed in a short period of time, the power accompanying the inertia of the recording paper and the mechanism for conveying the recording paper is large, and the power consumption is large. In addition to the problem that a power supply unit is required, the recording paper intermittently starts and stops repeatedly, so that the recording paper and the mechanism vibrate, and there is a problem that noise is generated.

In order to solve this problem, Japanese Patent Laid-Open No. 4-113
As shown in Japanese Patent Publication No. 870, a serial printer that performs recording while continuously transporting recording paper has been proposed.Since it is one-way printing, not only high-speed recording is difficult but also the carriage is scanned at a high speed. It is necessary to return to the start position, and on the contrary, there is an inconvenience that the instantaneous electric power increases and noise accompanying high-speed movement of the carriage occurs.

The present invention has been made in view of such a problem, and an object of the present invention is to achieve high-speed recording while minimizing a time variation in load on various driving sources. Another object of the present invention is to provide a serial printer with reduced noise and vibration.

[0007]

According to the present invention, there is provided a paper feed mechanism for continuously feeding a recording sheet at a constant speed, and a reciprocating movement in a width direction of the recording sheet. A carriage, a recording head mounted on the carriage to print on the recording paper, and moving the recording head forward on the carriage in the moving direction of the recording paper at the same speed as the paper feeding speed of the recording paper. And head movement driving means for moving backward at a speed higher than the paper feed speed in a direction opposite to the moving direction of the recording paper, wherein at the stage when the recording head reaches a side end of the recording paper, The head movement driving means starts moving the recording head in the paper feed direction of the recording paper.

[0008]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a first embodiment of the present invention. FIG. 1 shows a first embodiment of the present invention.
FIG. 1 is a perspective view of a serial printer according to an embodiment. In this embodiment, the printing principle is based on the ink jet system. The recording head 2 mounted on the carriage 21 scans on the recording paper 1. The recording paper 1 is transported in the direction of arrow A by the first paper transport rollers 4 and 5 and the second paper transport rollers 6 and 7.

As shown in FIG. 3, the recording head 2 moves N nozzles in the transport direction of the recording paper 1 (indicated by an arrow A in FIG. 1).
At intervals of p. Therefore, the distance between the centers of the nozzles at both ends is (N-1) × p, and L = N × p is the effective recording width.

The recording head 2 is mounted on a carriage 21 which is guided by guide shafts 22 and 23 via a gap with the surface of the recording paper 1. The carriage 21 scans the recording paper 1 in the direction of arrow B perpendicular to arrow A by the carriage movement driving unit 25. The head movement driving means 8 is mounted on the carriage 21 and reciprocates the recording head 2 in the direction of arrow A. The recording head 2 is connected to an unillustrated electric signal and power supply wiring and an ink supply conduit 99.

The recording head movement by the head movement driving means 8 will be described. The recording head 2 is supported by support leaf springs 61 and 62 and is biased. The head movement driving means 8 is configured to wind the driving plate 63 made of a thin metal plate, and moves the recording head 2 to an arbitrary position in the direction of arrow A according to the winding amount.

The guide shafts 22, 23, the carriage movement driving means 25, the supporting plate springs 61, 62, the carriage 21, the head movement driving means 8, and the driving plate 63 constitute a scanning means.

Next, the operation will be described. FIG. 4 shows a sequence diagram of the operation of each member shown in FIG. In FIG. 4, time (t) is shown on the horizontal axis, and the recording paper moving speed, the carriage moving speed, the recording head moving speed on the carriage,
3 shows a recording head drive signal.

At the time of recording operation, the carriage 21 is reciprocated in the direction of arrow B, and ink droplets are ejected from predetermined nozzles while the recording paper 1 is conveyed at a constant speed in the direction of arrow A.

The scanning operation will be further described with reference to FIG. FIG. 2 shows a scanning locus of the recording head 2 on the recording paper 1. The recording paper 1 is moved in the direction of arrow A, and the carriage 21 reciprocates. First, in the forward path, the recording head 2 is moved at a constant speed in the direction indicated by the speed component VH1 while performing the carriage movement in the direction indicated by the speed component UH1 in FIG. As a result, the recording head 2 moves the recording paper 1 to U
Scanning is performed in the first direction synthesized by H1 and VH1.

As is apparent from FIG. 4, when the print end area is reached at the other end, the carriage 21 is decelerated, and in this process, the recording head 2 is returned to the original position rapidly. Since the mass of the recording head 2 is small, fluctuations in load, noise, and vibration are extremely small as compared with high-speed return of the carriage and intermittent paper feeding of the recording paper.

Next, in the step of returning, the speed component UH2 shown in FIG.
The recording head 2 is moved at a constant speed in the direction indicated by the velocity component VH2 while performing the carriage movement in the direction indicated by. As a result, the recording head 2 scans the recording paper 1 in the second direction in which UH2 and VH2 are combined. That is, the first and second directions in which the recording head 2 scans are not orthogonal to the moving direction of the recording paper.

The moving speed of the recording paper 1 is VT, the carriage 2
When the time required for acceleration 1 is T2, the time required for moving in the direction of arrow B and the direction opposite to arrow B is T1, the time required for deceleration is T3, and when D and L are the dimensions shown in FIG. It is set to satisfy the following conditions.

L = VT × (T1 + T2 + T3) VT = VH1 = VH2 UH1 = −UH2 D = VT × (T2 + T3)

As a result, the locus of the recording head 2 moved by the scanning operation in the first direction becomes an area 81. Next, the carriage 21 is reversed, and the trajectory of the recording head 2 moving by the scanning operation in the second direction becomes an area indicated by 82. A head drive signal is applied to the print head 2 in accordance with the print image in this area to selectively discharge ink droplets from each nozzle to form an ink image. Recording paper 1 has speed V
Since the scanning movement trajectory is moving at T at a constant speed, the above-described scanning operation trajectory is an area parallel to the direction of the arrow B like the recording areas 83 and 84 on the recording paper 1. Therefore, the recording paper 1 can be scanned without gaps by continuous scanning.

In the configuration of this embodiment, the scanning operation
An ink image is formed in a belt-like area (83, 84 in FIG. 2) parallel to the direction perpendicular to the moving direction of the recording paper 1. By the repetitive scanning of the recording head 2, recording can be performed so that the surface of the recording paper 1 is painted without gaps. That is, the scanning is performed line-sequentially in the direction crossing the recording paper 1, but the recording paper 1 does not intermittently move as in a conventional serial printer, and the moving speed of the recording paper 1 can be kept constant. Therefore, compared to the case where the recording paper is conveyed intermittently, the instantaneous load for accelerating and decelerating the recording paper and the mechanism for conveying the recording paper is reduced, the fluctuation in power consumption is reduced, and vibration,
Generation of noise is suppressed. Further, since printing is performed in both the forward and backward steps of the print head 2, printing can be performed at high speed.

FIG. 5 shows a second embodiment of the present invention. Second
The main difference between this embodiment and the first embodiment is the moving means of the recording head 2. Other carriage movement driving means and recording paper movement means are the same as in the first embodiment, and description thereof will be omitted. Carriage 2
1, and a guide plate 50 is provided above the guide shafts 22 and 23. A guide groove 51 is formed in the guide plate 50, and the scanning operation of the recording head 2 is performed by the slider 52 guided by the guide groove 51 in the first direction (the direction indicated by the arrow G) and the second direction in accordance with the movement of the carriage 21. (In the direction indicated by arrow H).

Guide plate 50, carriage 21, slider 5
2. The guide shafts 23 and 24 constitute scanning means. Further, the position of the head in the recording paper transport direction is uniquely determined by the position of the carriage 21.

As in the case of the first embodiment, the surface of the recording paper 1 is recorded in such a manner that the recording paper 1 is continuously conveyed by the repetitive scanning of the recording head 2 while continuously conveying the recording paper. Further, scanning is performed in a line-sequential manner in a direction crossing the recording paper 1, and the recording paper 1 moves at a constant speed during operation.

[0025]

As described above, according to the present invention, a paper feed mechanism for continuously feeding a recording paper at a constant speed, a carriage reciprocating in the width direction of the recording paper, and a carriage mounted on the carriage. A recording head for printing on recording paper,
A head that moves the recording head forward on the carriage in the direction in which the recording paper moves at the same speed as the recording paper, and moves backward in the direction opposite to the direction in which the recording paper moves. Moving drive means, and when the recording head reaches the side edge of the recording paper, the head moving driving means starts moving the recording head in the paper feeding direction of the recording paper, so that the recording paper transport is It is performed continuously at a constant speed, and it is not necessary to return to the initial position due to the high-speed movement of the carriage. Vibration and noise can be suppressed by feeding.

[Brief description of the drawings]

FIG. 1 is a perspective view of a serial printer according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a scanning operation of the serial printer according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a nozzle arrangement of a recording head used in the serial printer according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a relationship between a recording head scanning speed and a recording paper transport speed in the first embodiment of the present invention.

FIG. 5 is a perspective view of a serial printer according to a second embodiment of the present invention.

FIG. 6 is a diagram illustrating a relationship between a recording head scanning speed and a recording paper conveyance speed in the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording paper 2 Recording head 8 Head movement drive means 21 Carriage 25 Carriage movement drive means 50 Guide plate 51 Guide groove 52 Slider

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41J 19/00

Claims (3)

(57) [Claims] 1. A paper feed mechanism that continuously feeds a recording sheet at a constant speed, a carriage that reciprocates in the width direction of the recording sheet, and a recording head that is mounted on the carriage and prints on the recording sheet. Moving the recording head on the carriage at the same speed as the paper feeding speed of the recording paper in the moving direction of the recording paper, and moving the paper feeding speed in the direction opposite to the moving direction of the recording paper. And a head movement driving means for moving the recording head backward at a higher speed than when the recording head reaches a side edge of the recording paper, the head movement driving means moving the recording head in a paper feeding direction of the recording paper. To start a serial printer. 2. The serial printer according to claim 1, wherein said head moving drive means is constituted by a reciprocating drive means provided on said carriage. 3. A guide groove formed in a member disposed so as to cover a movement range of the carriage, wherein the head movement driving means has one end fixed to the carriage, and the other end fixed to the carriage.
2. The serial printer according to claim 1, further comprising a slider guided by said guide groove.