JPH06182979A - Ink jet recording apparatus - Google Patents

Abstract

PURPOSE:To realize a transfer type ink jet recording apparatus eliminating wasteful operation and capable of performing high speed printing. CONSTITUTION:An image writing completion signal 54 is inputted to a flip-flop 56 to form a signal reversed at every image writing process. This signal is inputted to a stepping motor signal forming circuit 52 as the rotary direction signal of a drum moving motor 18 and further inputted to a writing data reading circuit 22 to change over the reading method of a writing data memory 23 corresponding to a drum moving direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus. In particular, the present invention relates to a transfer-type inkjet recording apparatus that forms an ink image on a transfer medium by a line-type recording head and then transfers the image to the recording medium to perform recording.

[0002]

2. Description of the Related Art Not only ink jet printers, but also wire dot printers, thermal printers, and the like, serial printers that scan the recording head in a direction perpendicular to the recording paper conveyance direction can perform recording while moving the recording head in both directions. It is known that such a device can shorten the recording time.

Further, as a transfer type ink jet printer using a line head having a plurality of nozzles arranged in a straight line, an ink jet recording head having a plurality of nozzles (hereinafter referred to as a recording head) with a gap formed in a cylindrical transfer medium. Called).

When an ink image is formed on the transfer medium by the recording head, the transfer medium forms an ink image on the cylinder while moving in the direction parallel to the plurality of nozzles by the image signal in synchronization with the rotation of the cylindrical transfer medium. To go. Then, the recording medium is brought into contact with the transfer medium and pressed from behind the recording medium to transfer the ink image onto the recording medium, convey the recording medium in the paper discharge direction, and move the transfer medium to the image forming start position. The method of returning is taken.

According to this structure, the ink image on the transfer medium is not deformed or soaks into the recording paper in the transfer process. Therefore, due to the pressure transfer, the ink image on the transfer medium is faithfully transferred to the recording paper without deterioration of the image quality, and a high quality image is obtained.

[0006]

However, in the bidirectional movement of the recording head in the serial printer, the continuous dot rows in the conveying direction of the recording medium are likely to be displaced,
It is difficult to improve the image quality.

On the other hand, in a transfer type ink jet printer using a line head, since the ink image formation is performed by moving the transfer medium in one direction, the transfer medium is moved to the image formation start position before or after the image formation is completed. Need to return to. The step of returning the transfer medium to the image forming start position cannot be performed during the transfer step because the transfer from the transfer medium to the recording medium is pressure transfer, and the return step is performed alone. That is, the recording time increases. Furthermore, if the moving speed of the transfer medium during the returning process is made higher than the moving speed during image formation in order to shorten the recording time, the moving means of the transfer medium becomes complicated.

The present invention solves this problem, and an object thereof is to obtain a transfer type ink jet recording apparatus which can perform high speed recording and can obtain a high quality image.

[0009]

The ink jet recording apparatus of the present invention is an ink jet recording apparatus which forms an ink image on the surface of a transfer medium in an image writing step and transfers the ink image to the recording medium in the transfer step to obtain an ink image. Then, the line head, which is provided with ink discharge nozzles at regular intervals on a straight line, faces the recording head with a gap,
A cylindrical transfer medium which is rotatably and movably supported in the rotation axis direction, moves a predetermined amount in the rotation axis direction for each rotation in the image writing step, and in which the moving direction is reversed in each writing step; And a transfer unit that transfers the ink image on the medium to the recording medium.

[0010]

According to the above construction, since the moving direction of the transfer medium in the image writing step is reversed every time one page is output, the return of the transfer medium after the transfer step can be omitted, and high-speed recording can be performed. Can be configured.

[0011]

EXAMPLES The ink jet recording apparatus of the present invention will be described in detail below with reference to examples.

FIG. 1 is a perspective view of an ink jet printer which is a first embodiment. An inkjet recording head 2, a transfer roller 3 that is a transfer unit, and a recording paper 4 that is a recording medium are sequentially arranged around a transfer drum 1 that is a transfer medium.

The recording head 2 is an ink jet recording head of a type using a piezoelectric element, and is supplied with ink from an ink container 28 through an ink supply pipe 29, and has a plurality of nozzles at regular intervals in the axial direction of the transfer drum 1. ing. In the case of this embodiment, the recording head 2 has 512 nozzles at a 16/600 inch pitch.

The transfer drum 1 is formed by laminating an elastic layer made of silicone rubber around a metal tube having an outer circumference of 10 mm.
Inches. The transfer drum 1 is driven by a drum drive motor 11, and the rotation speed is controlled by an output signal of a rotary encoder 12 mounted on the transfer drum 1. The output signal of the rotary encoder 12 further serves as a reference for the print timing of the recording head and the transfer drum movement timing.

The lever 15 is swingably attached to a lever shaft 14 as a fulcrum, and one end portion 15b of the lever 15 is in contact with the end surface of the rotary shaft of the transfer drum 1. Also lever 1
A bearing plate 16 is fixed to the other end 15a of the bearing 5. Further, the spring 1 is attached to the drive motor side bearing 13 of the transfer drum 1.
9 is attached and pushes the transfer drum 1 in the direction of arrow B. As a result, the bearing plate 16 is brought into contact with the shaft 18. The shaft 18 is threaded and can be moved in the axial direction by rotation of the motor 17. The motor 17 is a step motor, which makes one rotation in 20 pulses and the shaft 18 moves 0.5 mm. The moving ratio of the lever 15 is 11.81, and when the shaft 18 moves 0.5 mm, the transfer drum 1 moves to 1/600.
Move in the direction of arrow B or C.

The transfer roller 3 is an aluminum metal roller, and is structured so that it can be pressed and released from the transfer drum 1 by the transfer pressure applying device 33. When pressed, it rotates in the direction of arrow D in the figure through the recording paper 4 at the same speed as the peripheral speed of the transfer drum 1. The transfer pressure is 1 in this embodiment.
It is controlled in the range of 0 to 50 kg weight.

Next, the operation will be described. In this embodiment, the recording head 2 has 512 nozzles along the axial direction of the transfer drum 1 at a 16/600 inch pitch. The image formation includes two steps of an image writing step of forming an ink image on the transfer drum 1 and a transfer step of transferring the ink image formed on the transfer drum to a recording sheet.

The image writing process will be described with reference to FIGS. In the image writing process, the transfer roller 3 is controlled so as not to contact the surface of the transfer drum 1. Next, while the transfer drum 1 makes one rotation in the direction of arrow A, nozzles (nozzle 200, nozzle 20 in FIG.
Ink is ejected from the two nozzles 1 to be described as a representative) to form an ink image. This is indicated by dot rows 202 and 203 in FIG. While the transfer drum 1 makes one rotation, the transfer drum 1 moves in the arrow B direction by the distance p shown in FIG. The moving operation of the transfer drum 1 can be performed intermittently or continuously. In the case of continuous movement, the dot rows 202, 203, ... Have an inclination with respect to the rotation direction of the transfer drum 1. here,
P = 1/600 inch with respect to the transfer drum moving direction. After that, the transfer drum 1 enters the second rotation. Similarly to the first rotation of the transfer drum 1, a dot row is formed on the transfer drum 1 with a distance p from the previous dot row. Similarly, since the nozzle pitch h = 16/600 inches, the transfer drum 1 rotates 16 times and an image for one page is formed on the transfer drum 1.

Next, the transfer process will be described. After the image for one page is formed on the transfer drum 1, the transfer roller 3 is pressed against the transfer drum 1. At a timing so that the recording area 15 corresponds to the recording paper, the paper conveying means 4 is attached to the contact portion.
The transfer is started by conveying the recording paper 4 according to 1.
The transfer roller 3 is separated from the transfer drum 1 and the recording paper 4 is ejected at the timing when the leading end of the recording paper 4 has finished the transfer and passed the contact portion.

Recording of one page is completed as described above, but in the subsequent recording, the moving direction of the transfer drum 1 in the image writing step is the direction of arrow C opposite to that in the previous image writing step. The image writing order is as shown in FIG. The transfer process is exactly the same as the last time.

Next, a method of switching the moving direction of the transfer drum will be described with reference to FIG. The encoder 12 applies light to the outer peripheral edge of the transfer drum 1 and reads the reflected light, which is 1/60
A pulse is generated every 0 inch, and the transfer drum 1 generates 6000 pulses per revolution. The frequency dividing circuit 51 is the encoder 1
The pulse generated in 2 is divided into 1/300. As the write end signal 54, one pulse is generated each time writing of one page is completed. The moving direction initialization signal 55 generates one pulse when the power is turned on. Flip flop 56
The output is fixed to "0" level by the movement direction initialization signal 55, and the output is inverted every time the pulse of the write end signal 54 is input. This signal determines the drum moving direction. When the signal level is "0", the transfer drum 1 moves in the direction of arrow B shown in FIG. 1, and when the signal level is "1", the transfer drum 1 moves in the direction of arrow C. Moving. The drum movement permission signal 57 outputs a "1" level signal during the image writing process and a "0" level signal during the transfer process. The step motor signal generation circuit 52 generates a drive pulse for the drum moving motor 18 based on the motor clock signal from the frequency dividing circuit 51, the drum movement direction signal from the flip-flop 56, and the drum permission signal 57, and the step motor driver 53 causes the motor 18 to drive. Is driven. Recorded data from the outside is expanded and held in the write data memory 23. The write data read circuit 22 selects the read order of the write data memory 23 according to the output level of the flip-flop 56, and transfers the data from the write data memory 23 to the read recording head driver 21 in synchronization with the pulse of the encoder 12. The recording head driver 21 drives the recording head 2 according to the write data.

In the present embodiment, the step motor and the lever are used to move the drum, but the present invention is not limited to this, and other motors and configurations may be used.

[0023]

According to the present invention, by bidirectionally moving the transfer drum during image writing, there is no need to move the transfer drum except in the image writing process, and the recording time can be shortened without wasteful operation. Has the effect.

[Brief description of drawings]

FIG. 1 is a perspective view of an inkjet recording apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view showing the configuration of the transfer drum movement of the inkjet recording apparatus according to the embodiment of the present invention.

FIG. 3 is a diagram showing a recording method of an inkjet recording apparatus according to an embodiment of the present invention.

FIG. 4 is a diagram showing a recording method of an inkjet recording apparatus according to an embodiment of the present invention.

FIG. 5 is a diagram showing a drum movement switching method of the inkjet recording apparatus according to the embodiment of the present invention.

[Explanation of symbols]

 1 Transfer Drum 2 Recording Head 3 Transfer Roller 4 Recording Paper 12 Transfer Drum Rotation Encoder

Claims (1)

[Claims] 1. An ink jet recording apparatus for forming an ink image on a surface of a transfer medium in an image writing step and transferring the ink image to a recording medium in the transfer step to obtain an ink image. Is provided so as to face the recording head with a gap therebetween, and is supported so as to be rotatable and movable in the rotation axis direction. In the image writing process, the line head is moved by a predetermined amount in the rotation axis direction. Then
An ink jet recording apparatus comprising: a cylindrical transfer medium whose movement direction is reversed at each writing step; and a transfer means for transferring an ink image on the transfer medium to the recording medium.