JPH05261911A - Perfecting ink jet printer - Google Patents

Abstract

PURPOSE:To form a high quality image without set-off, carry out the formation of ink image on both sides of a recording paper simultaneously, make a device small and carry out high speed printing in a perfecting ink jet printer, and further carry out perfecting by using a single recording head. CONSTITUTION:An ink jet type recording head is disposed to change over its positions from a first recording position 13-a to a second recording position 13-b, and ink image recording is carried out on a first transfer medium 11-a at the first recording position 13-a, while ink image recording is carried out on a second transfer medium 11-b at the second recording position 13-b. The first and second transfer mediums 11-a and 11-b carrying the ink image records are brought into contact with each other, and said contact section is passed over a recording paper 21 and ink image recording is carried out on the recording paper 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer for forming ink images on recording paper, and more particularly to a double-sided printing ink jet printer for forming ink images on both front and back surfaces of recording paper.

[0002]

2. Description of the Related Art Ink jet printers discharge liquid ink onto recording paper to perform recording with ink drops. On the other hand, as a printer capable of double-sided printing, an electrophotographic apparatus has been put into practical use. In an electrophotographic double-sided printing printer, after printing on one side of the recording paper, the recording paper is reversed to perform printing on the back surface, which requires a recording paper reversing mechanism, which increases the size of the apparatus. It had a problem of long recording time. The ink jet system can be easily configured to perform recording on both front and back sides without reversing the recording paper, and the double-sided printing apparatus can be downsized and high-speed printing. Such a device
For example, an apparatus as disclosed in JP-A-58-56860 is known. This apparatus has two print heads for recording on one side of the recording paper, and records on each side.

[0003]

In the ink jet printer, it is necessary to use the ink in a state in which the ink has a sufficiently low viscosity in order to be ejected as ink droplets. In this case, the ink, which is a low-viscosity liquid, permeates the recording paper when it adheres to the recording paper. Therefore, when recording on the surface, the ink that has permeated penetrates the ink image to the back side of the recording paper (hereinafter referred to as show-through). ) It was not suitable for double-sided printing.

Further, when double-sided printing is performed, it takes time to dry the ink soaked in. The longer the drying time of the impregnated ink, the more the impregnation progresses. In order to prevent the deterioration of the image quality due to the penetration, it is necessary to perform recording on the other side after the elapse of a certain time for the recording on one side to dry. If you record at the same place on both sides,
This is because a large amount of ink adheres to the recording paper, and the show-through and image quality deterioration due to the penetration are remarkable. In such a configuration,
After recording on one side, it is necessary to dry it and record on the other side. That is, it is necessary to provide recording heads for recording on the front and back sides at different places, and it is not suitable for high-speed recording because recording on both sides involves a time delay. Further, it is necessary to provide separate recording heads for recording on both sides of the recording paper.

The present invention solves these problems.
An object of the present invention is to provide a new double-sided inkjet printer capable of performing double-sided printing with the least amount of ink penetration in the inkjet printer.

Another object of the present invention is to provide a double-sided printing ink jet printer which records on both sides of a recording paper with a single head.

[0007]

SUMMARY OF THE INVENTION The double-sided printing ink jet printer of the present invention achieves the above object.
An ink jet recording / writing unit that ejects ink as droplets and two transfer media that carry and move the ejected ink droplets are provided, and a recording image is written on the first transfer medium by the recording / writing unit. Next, a recording image is written on the second transfer medium by the recording / writing means, and then, the recording image on the first transfer medium is transferred to the first surface of the recording medium and then on the second transfer medium. The recording image is transferred onto the second surface of the recording medium at the same time.

[0008]

With this structure, a recording ink image is formed on two transfer media corresponding to both sides of the recording paper by one ink jet recording / writing means, and thereafter, the recording ink images are formed on both sides of the recording paper. Transfer at the same time.

[0009]

EXAMPLES The examples shown below will be described.

1 and 4 show a first embodiment of the present invention.

In FIG. 1, this double-sided printing ink jet printer has arrows A- around the first and second transfer drums 11-a and 11b which are the first and second rotating transfer media.
The recording head 13 and the first and second removing rollers 12-a and b and the first and second collecting tanks 14 that are ink jet type recording / writing means are sequentially arranged from the upper side in the rotational direction indicated by a and b.
It is provided with a and b.

This double-sided ink jet printer is
An ink image is formed on the outer circumferences of the second transfer drums 11-a and 11b in a state where they are not in contact with each other, and then transferred to the recording paper 21, which is the second transfer shown by the solid line in FIG. The drum 11-b indicates the position at the time of ink image formation, and the second transfer drum 11-b indicated by the broken line indicates the position at the time of transfer to the recording paper. FIG. 1 illustrates the first and second ink images formed.
The transfer drums 11-a, 11b of
11 shows a state in which an ink image is formed on the transfer drum 11-b. The recording head 13 can be switched between two recording positions, and an ink image is formed on the first transfer medium 11-a at the first recording position 13-a (shown by broken lines in FIGS. 1 and 4). , And is configured to form an ink image on the second transfer medium 11-b at the second recording position 13-b.
That is, the recording position switching device 24 causes the recording head 13 to
Is rotated in the direction of arrow G to switch the recording position. The area 23-a indicated by hatching is the first transfer drum 11-.
A print area where recording is performed by the recording head 13 is shown on a. (The printing area on the second transfer drum 11-b is shown in FIG.
No part of the number is attached because it appears only partially. ) Since the members arranged around the first transfer drum 11-a are the same as the members arranged around the second transfer drum 11-b, the members arranged around the first transfer drum 11-a. Regarding (about omitting the subscripts a and b), the configuration of each member will be described.

The transfer drum 11 is constructed by providing a conductive elastic layer 17 around a metal tube 16. Conductive elastic layer 1
7 can be obtained from a rubber material in which a conductive compound such as carbon black or metal powder is dispersed. As the rubber material, a material that easily peels off the ink image is desirable, and chloroprene rubber, nitrile rubber, ethylene propylene rubber, silicone rubber, fluorosilicone rubber, and fluororubber can be used. A guide groove 18 is formed around this area so as to avoid the print area 23. The recovery blade 19 is the guide groove 1.
The ink in the guide groove is peeled off and collected in the collecting tank 14.

The recording head 13 is an ink jet recording head of the type using a piezoelectric element, and according to a recording signal,
Ink is selectively ejected from a plurality of nozzles as ink droplets.

The nozzles are arranged in the axial direction of the transfer drum 11, and the recording head 13 and the transfer drum 1 are in operation during the recording operation.
Fixed to 1.

The ink is an emulsion ink in which positively charged toner, which is a colored particle, is dispersed in a carrier liquid, which is a dispersion medium. The dispersion medium is a high resistance low dielectric constant aliphatic hydrocarbon solvent (for example, Isopar G manufactured by Exxon Chemical Co.), and the toner is composed of Raven 1255 manufactured by Columbian Carbon Co. as a pigment and ethyl cellulose as a resin. The ink is formed by dispersing the toner in a dispersion medium together with a charge control agent organic amine. The toner is positively charged.

The recording paper 21, which is a recording medium, is conveyed in the direction of arrow C, reaches the abutting portion of the first and second transfer drums 11-a, b, and is conveyed while being sandwiched between them and being pressed.

As shown in FIG. 2, the removing roller 12 is constructed by providing a conductive elastic layer 53 around the metal tube 22. Further, an insulating layer may be provided on the outermost layer.

The ink concentration operation of the removing roller 12 will be described with reference to FIG. The ink droplets ejected by the recording head 13 form ink dots 40 on the transfer drum 11. The transfer drum 11 is biased to the removal roller 12 at a negative potential by the bias power source 41. Since the toner in the ink is positively charged, it receives an electrostatic force due to the voltage and moves to the transfer drum 11 side and adheres thereto.
When the ink dots 40 pass through the contact portion 70 with the removing roller 12, the ink liquid is squeezed by the squeezing action and remains on the upper hand 50 of the contact portion 70. Since the toner has an electrostatic adhesion force, it passes through the contact portion 70. As a result, the carrier liquid component is removed below the contact portion 70, and concentrated ink dots 42 having a high toner component concentration are obtained.

In the experiments conducted by the present inventors, the removal roller 12 having an outer diameter of 30 mm was used with respect to the transfer drum 11 having an outer diameter of 110 mm.
Using an ink in which a toner having a charge amount of 300 μC / g is dispersed, the bias power source 41 is set to 500 V,
80% of the carrier liquid was removed from the ink dots 40.
Since the ink image is in a concentrated state, it does not soak into the recording paper 21. In addition, even if pressure is applied during transfer, there is no crushing deformation. Therefore, this was transferred to a recording paper, and a good transferred image without show-through was obtained.

Next, the recovery of the carrier liquid remaining on the upper side 50 of the contact portion 70 will be described. A guide groove 18 is provided on the outer periphery of the transfer drum 11. The carrier liquid remaining above the contact portion 70 flows into the minute gap and is held by the capillary force. That is, it is held as shown by the retention section 50 in FIG. At this time, when the guide groove 18 reaches the contact portion 70, the gap increases corresponding to the groove depth. The carrier liquid is held in the smaller gap by capillary action. For this reason, the guide groove 18 is not held inside but is held along the edge portion 51 around the groove. Since the guide groove is formed in a spiral shape on the outer periphery of the transfer drum as shown in FIG. 1, the portion where the removing roller 12 and the edge of the guide groove 18 come into contact with each other moves as shown by an arrow D with rotation. Due to the characteristics of the liquid described above caused by the capillary action, the retained carrier liquid moves in the axial direction of the transfer drum 11 and finally, as shown in FIG.
To the left edge edge tip 22 of. When the edge tip 22 passes through the abutting portion 70, the carrier liquid is no longer held, so it falls due to gravity and is peeled from the groove at the left end portion by the peeling blade 19 and collected in the collecting tank 14.

During double-sided printing, the recording head 13 is moved to the first transfer position 11-at the first recording position 13-a.
An ink image is formed on a. Next, the second recording position 13-
In b, an ink image is formed on the second transfer medium 11-b. After the ink images corresponding to both surfaces of the recording paper 21 are formed on the first and second transfer drums 11-a and 11-b, the first and second transfer drums 13-a and 13-b are formed. The recording paper 21 is brought into contact with each other, pressure is applied thereto, and the recording paper 21 is passed through this contact portion. By the applied pressure, the ink image on the transfer drum is transferred to the recording paper 21, and an ink image record can be obtained on the recording paper 21. That is, the first transfer drum 11
The recorded image on −a is on the upper surface (shown in FIG. 1) of the recording paper 21,
The recorded image on the second transfer drum 11-b is transferred to the lower surface of the recording paper 21, and the recorded images are simultaneously obtained on both sides of the recording paper 21.

In this apparatus, the one-sided printing can be performed by forming an ink image on one of the first and second transfer drums and transferring it to the recording paper.

In the apparatus of this embodiment, the ink recording image formed on the transfer drum 11 is transferred onto the recording paper in a dried or concentrated state after removing the carrier liquid on the transfer drum 11. Therefore, ink does not soak into the recording paper, and the recorded image on one side does not show through. Therefore, when recording on both sides,
It is not necessary to form a recorded image on one side and, after it has dried, record on the back side. Therefore, it is possible to record on both the front and back sides at the same place at the same time. As a result, the time required for recording can be shortened and the device can be downsized.

Further, in the apparatus of this embodiment, the recording head 1
3 is sequentially placed at two recording positions, and recording is sequentially performed on the first and second transfer drums. Therefore, it is possible to perform recording on the front and back surfaces of the recording paper with one recording head.

Next, a second embodiment will be described with reference to FIG.

The second embodiment differs from the first embodiment in the nozzle arrangement in the recording head and the scanning method for recording an ink image on the transfer drum, and the apparatus configuration and the recording method are the same as those in the first embodiment. Is the same as. This device is a device for recording at a pitch of 1/300 inch. Recording head 13
Aligns multiple nozzles in the axial direction of the transfer drum 11,
They are arranged at a pitch of 8 × 1/300 inches. At the time of recording, in synchronization with the rotation of the transfer drum 11, the recording head oscillating means 25 also serving as a recording position switching device causes the recording head 13 to oscillate in the axial direction of the transfer drum 11 (indicated by an arrow H in FIG. 5). To do. The scanning operation during recording will be described with reference to FIG. This figure is a view seen from the direction of arrow F in FIG. To simplify the description, the recording head 1
3 shows a case where 3 has 3 nozzles.

The recording head 13 has a first recording position 13-
At a, image recording is performed on the first transfer drum 11-a. First, the first transfer drum 11-a and the second transfer drum 11-b are placed in a non-contact state, and a gap R
Keep on. The recording head 13 is placed at the first recording position 13-a, and is oscillated by the oscillating device 25 within a range indicated by P (a length corresponding to the nozzle arrangement pitch).

By rotating the first transfer drum 11-a at a constant speed and moving the recording head 13 in the direction of arrow Q, recording is performed in the belt-shaped area using each nozzle. At this time, the recording head 13 is 1/3 in the Q direction.
When moving 00 inches, the first and second transfer drums 11-
The speed is set so that a rotates once. FIG. 6 shows a state in which the swing amount of the head reaches S. A state in which recording is performed in the area indicated by 61 ... on the first transfer drum 11-a by the first nozzles 61 ... of the recording head 13 (the second and subsequent nozzles are the same, so description thereof is omitted). Is shown.

By swinging until S coincides with P, the required printing scan is completed and printing is performed over the entire printing area. After the image recording is performed on the first transfer drum 11-a in this manner, the recording head 13 is moved to the second recording position 13
-B, in the same manner as above, the second transfer drum 11
Form an ink image on -b. After that, the first and second transfer drums 13-a and 13-b are brought into contact with each other to apply pressure,
The ink image on the transfer drum is transferred to the recording paper 21 by passing the recording paper 21 through the contact portion and applying pressure, and an ink image recording can be obtained on the recording paper 21.

[0031]

As described above, according to the present invention, the ink recording image formed on the transfer drum is transferred onto the recording paper. Therefore, the recording paper is not soaked with ink and the recorded image on one side does not penetrate to the back side. Further, in double-sided recording, it is not necessary to wait for the recording image on one side to dry before recording on the back side. Therefore, recording can be performed on the front and back sides at the same place at the same time. As a result, the time required for recording can be shortened and the device can be downsized.

Furthermore, since the ink image recording on the two transfer media is performed by a single ink image recording means, it is not necessary to provide a plurality of recording means.

Therefore, there is an effect that it is possible to realize a new double-sided printing ink jet printer which has a small amount of ink penetration and is capable of high-speed printing.

Since the recording head can perform ink image recording on both the front and back sides of the recording paper at two recording positions, in the case of single-sided recording, the recording position can be selected in the same apparatus by face-up ejection. (The recording surface of the recording paper faces up, and the succeeding recording surfaces are sequentially ejected so as to overlap with this.), Face-down paper ejection (the recording surface of the recording paper faces down, and the succeeding recording surfaces sequentially. It is also ejected so that it is overlapped on this).

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a double-sided printing inkjet printer according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating an ink concentrating action of the double-sided inkjet printer according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a residual carrier liquid recovery operation of the double-sided printing inkjet printer according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view showing the configuration of the double-sided printing inkjet printer according to the first embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of a double-sided printing inkjet printer according to a second embodiment of the present invention.

FIG. 6 is a diagram illustrating a scanning method of a double-sided printing inkjet printer according to a second embodiment of the present invention.

[Explanation of symbols]

11-a, b: first and second transfer drums (transfer medium) 13-a, b: first and second recording positions of recording head (ink jet recording / writing means) 21: recording paper (recording medium) 24: recording position switching device 25: rocking device

Claims (2)

[Claims] 1. An ink jet recording / writing device that ejects ink as liquid droplets, and two transfer media that carry and move the ejected ink liquid droplets. The recording / writing device is provided on the first transfer medium. , Writing a recording image on the second transfer medium by the recording / writing means, then transferring the recording image on the first transfer medium to the first surface of the recording medium, and 2. A double-sided printing ink jet printer characterized in that the transfer of the recorded image on the second transfer medium to the second surface of the recording medium is simultaneously performed. 2. The ink comprises toner and carrier liquid,
On the lower side of the recording / writing means, an ink concentrating or drying means for removing the carrier liquid from the ink recorded image on the transfer medium is provided before the transfer of the recorded image to the recording paper, and the concentrated or dried recorded image is recorded. The double-sided inkjet printer according to claim 1, wherein the ink-jet printer is transferred onto a medium.