JPH02251455A - Liquid jet recorder - Google Patents

Abstract

PURPOSE:To enable a high density high quality image to be record at high speed even on a light transmissive recording medium by a method wherein when recording is performed on the light transmissive recording medium, an image signal distributing means which distributes an image signal into two sets of driving devices of recording heads is established. CONSTITUTION:A recording medium 3 passes through a transmitted light amount measuring apparatus composed of LED lamp 6 and a photoelectric conversion device 7, and outgoing light of the LED lamp 6 reaches a photoelectric conversion device 6 occasionally to transmittance of the recording medium 3. The photoelectric conversion device 6 generates output S according to the transmittance of the recording medium 3. When the transmittance is high, an output level is taken as '1' and when the transmittance is low or '0', the output level is taken as '0'. In the case of non transmissive recording medium, an image signal is inputted to a driving device 8 with an image signal distributing device 10, and normal color recording is performed. Besides, in the case of the transmissive recording medium, C, M use ink jet recording heads 11, 12 on the recording medium front side are driven and at the same time, Y, K use ink jet recording heads 23, 24 on the recording medium back side are driven to form color images on the front and back two surfaces.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Use) The present invention relates to a liquid jet recording apparatus that performs recording by ejecting a recording liquid (ink) onto a recording medium.

[Conventional technology]

A feature of this type of liquid jet recording device is that it can use a variety of recording media; for example, transparent recording media such as OHP film, slide device film 1, and internally illuminated display device film can also be used. This is one of the possibilities.

When forming an image on such a transparent recording medium using a liquid jet recording device, a so-called inkjet printer,
Since it is difficult to provide sufficient ink absorbency to the transparent recording medium itself, an ink retaining layer made of an ink absorbing substance that is transparent or becomes transparent through post-processing (heating, etc.) is placed on the base of the recording medium. was established.

However, in this type of transparent recording medium, if the ink retaining layer is formed thickly or densely in order to provide sufficient ink absorption capacity, the transmittance may decrease, the retaining layer may easily peel off, or A problem arises in that manufacturing costs increase.

Therefore, the ink retaining layer can have only a limited range of ink absorbing ability. Therefore, when recording with a large amount of ink, such as monochrome high-density recording or Victorian color recording, on such a transparent recording medium, the ink may overflow on the recording medium and the image quality may deteriorate significantly. , it takes a long time for fixing and drying, and other problems arise. In order to avoid these problems, conventional inkjet printers: (1) Print multiple times at intervals that do not cause ink splatter.

(2) Print at a speed that does not cause ink splatter.

(3) For example, a heater is provided which also serves as a platen for regulating the recording surface of the recording medium to promote drying and fixing while recording.

(4) A heater or fan is provided in the recording medium ejection section of the apparatus to promote drying and fixing in this section.

Measures such as these were taken.

[Problems to be Solved by the Invention] However, in the inkjet printer that takes the above measures, the following problems may occur.

That is, countermeasures (1) and (2) increase the recording time and reduce the recording throughput.

In addition, in the case of countermeasure (3), since the heater is located on the back side of the recording surface, the distance from the recording head provided at the ink ejection port is short, and therefore the ink inside the ejection port dries, resulting in ejection failure, etc. Easy to occur. Furthermore, with countermeasure (4), if the heater and fan are installed inside the device, there will be a problem of temperature rise inside the device, and if they are installed outside the device, there will be a problem in terms of safety.

As described above, in conventional inkjet printers, especially when recording high-quality images and high-density high-quality images on transparent recording media, measures to ensure stable and high-speed recording have not always been sufficient.

In view of these problems, an object of the present invention is to provide a liquid jet recording device that is capable of recording high-quality images, high-quality, high-density images, etc., stably and at high speed on a transparent recording medium. shall be.

[Means for Solving the Problems] To this end, in the present invention, in order to perform recording by discharging liquid onto both the front and back sides of a recording medium, a recording head disposed on both sides of the recording medium and a light transmitting part are provided. When recording on a recording medium that has or has optical transparency, the image signal for recording is sent to a recording head placed on the front side of the recording medium and a recording head placed closer to the back side of the recording medium. The present invention is characterized by comprising an image signal distribution means for distributing and transmitting image signals.

[Function] According to the present invention, one unit of image information is formed on a recording medium that has optical transparency or is imparted with optical transparency by distributing image signals and recording on both the front and back sides. Ru. Therefore, since the amount of ink ejected per side is reduced, it is not necessary to provide such a recording medium with excessive ink absorption capacity or to reduce the recording speed. Also,
No deterioration in image quality occurs.

(Example〕 Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an example of the configuration of a full-color recording inkjet printer as a first embodiment of the present invention.

In FIG. 1, 1 is a group of inkjet recording heads arranged on one side with respect to the recording medium, and includes cyan, magenta, yellow, and black (hereinafter referred to as C, M, Y, and black).
Recording head for ejecting ink 11.12.13
．． Consists of 1.4. Reference numeral 2 designates an inkjet recording head group disposed on the opposite side of the inkjet recording head 1 across the recording medium, and in this embodiment, each ink jets each color of yellow and black. The recording heads 23 and 24 are respectively connected to the yellow recording head 13.
and is provided at a portion opposite to the black recording head 14.

3 is a recording medium, 4 is a conveyance roller, and 5 is a discharge roller. 6 is an LED lamp that illuminates the recording medium; 7
is a photoelectric conversion device including a phototransistor placed opposite to the LED lamp 6. 8 and 9 are drive devices for recording head groups 1 and 2, respectively. The driving device 9 is provided with a mirror image processing circuit in order to align the pixels formed on the front and back sides. 10 is a device for distributing image signals to these driving devices.

FIG. 2 shows an example of the configuration of the J-plane image signal distribution device. In this embodiment, the image signals related to C and M are the drive bag #
8 directly. Regarding the image signals related to Y, they are guided to one input terminal of each of AND circuits AY1 and AY2, and are also led to an inverting input terminal, which is the other input terminal of AND circuit AYI, and to the other input terminal of AND circuit AY2. leads to the output S of the photoelectric conversion device 7. Then, AND circuits AYI and AY2 are connected to drive devices 8 and 9, respectively. Regarding the image signal related to K and the photoelectric conversion device output S, 1 and A are also connected to the AND circuit A.
A similar configuration is adopted for K2.

The operation of the inkjet printer having the above configuration will be described below. The recording medium 3 is conveyed in the direction of the arrow in FIG. 1 between the recording head groups 1.2 while being applied with an appropriate tensile strength by a conveying roller 4 and a discharge roller 5. At this time, the recording medium 3 includes the LED lamp 6 and the photoelectric conversion device 7.
The recording medium 3
Depending on the transmittance of the LED lamp 6, the emitted light from the LED lamp 6 reaches the photoelectric conversion device 6. This photoelectric conversion device 6 includes a recording medium 3
It generates an output S according to the transmittance of
If the transmittance is low or OH, such as paper, it is set to "0". The image signal distribution device IO performs the following operation depending on whether the recording medium is transparent or not based on the electric signal S.

To illustrate the case of an image signal related to Y with reference to FIG. 2, if a transparent recording medium is used, the signal S
becomes "°°1", therefore, the AND circuit AYI deactivates the image signal regardless of the state of the image signal, and the image signal is not sent to the drive device 8. On the other hand, the gate of the AND circuit AY2 is opened, and the image signal is not driven. On the other hand, if the recording medium is non-transparent, the level of the electric signal S will be 0'', the gate of AND circuit AYI will be open, and the gate of AY2 will be open. When it is closed, the image signal is sent only to the drive device 8 side. The same applies to the image signal related to K. Furthermore, the image signals related to C and M are supplied as they are to the drive device 8 side.

That is, if the recording medium is not a transparent recording medium, an image signal is manually input to the drive device 8 associated with the inkjet recording head group 1 on the front side of the recording medium (upper side in FIG. 1), and normal color recording is performed. On the other hand, in the case of a transparent recording medium, the C and M inkjet recording heads 11 and 12 on the front side of the recording medium are driven, and at the same time, the Y and Y inkjet recording heads 23 and 24 on the back side of the recording medium are driven. Image signals are distributed so that a color image of the surface is formed.

According to experiments by the inventors, a recording head of 4000
Serial recording was performed using 128 ink ejection ports formed at a density of PI (dots/inch), and diethylene glycol (DEC) was used as the ink.
0% water-based ink was used, and polyethylene terephthalate (PET) with a thickness of 70 μm was used as a recording medium.
) When we created and used a film coated with polyvinyl alcohol (PVA) resin with a thickness of 10 μm on both sides, a color image was recorded with ink in C, M, and Y on the front side without distributing image signals. if you did this,
Depending on the image, ink splatter occurred, resulting in distorted images or problems such as ink adhering to the ejection roller.However, by distributing the image signals, we decided to distribute C and M inks on the front side and Y and Y on the back side. When a color image was recorded by ejecting the ink, a perfectly acceptable image quality was obtained, and the ink dried quickly and no problems such as ink adhering to the discharge roller occurred.

Note that the recording head group 2 may be arranged offset from the recording head group 1, that is, the recording heads 23 and 13 and the recording heads 24 and ]4 do not have to be arranged facing each other, In that case, the deviation may be corrected by providing a delay circuit or the like.

FIG. 3 shows an inkjet recording apparatus according to a second embodiment of the present invention, and corresponding parts are given the same reference numerals as those in FIG. 1.

In this example, the recording heads 11 to 1 for C, M, and Y on the front side are
C, M, Y on the back side, facing 4 respectively.

K recording heads 21 to 24 are distributed. Further, 30 is a use notification device for a transparent recording medium, and for example, when the recording medium to be used is transparent or one that is imparted with transparency through post-processing (simply referred to as a transparent recording medium), the operator The image signal distributing device 20 has a switch that accepts an instruction manual force, and a means for notifying the image signal distribution device 20 that a transparent recording medium is to be used in response to the switch operation.

FIG. 4 shows an example of the configuration of the image signal distribution device 20 according to this example.

Here, 20C, 20M, 20Y, and 20 are distribution circuits corresponding to image signals of C, M, Y, and K, respectively, and an image signal transfer lock CLK and a transparent recording medium usage notification device. 17 outputs A to the switch terminal SW and control terminal CTR, respectively.
Accept to L. The circuit configuration is such that the image signal path is driven in accordance with the clock signal CLK that is input to the switch terminal SW when the control terminal CTRL receives a level "1" signal A that is supplied when using a transparent recording medium. It is possible to have a switching element that switches to the device 8 or 9 side and maintains the image signal path only on the drive device 8 side when the signal A is 0''.

In the above configuration, when recording is performed on a transparent recording medium, for example, when the transparent recording medium use notification device 30 is manually activated, the image signal distribution device 20 is activated by a human signal from the notification device 17. Inkjet recording head 11 for C, M, and Y on the front side of the recording medium.
In order to selectively drive both the inkjet recording heads 21 and 22.23.24 for C, M, and Y on the back side and to form a color image, image signals are respectively driven. Allocate and input to device 8.9. When using a transparent recording medium in this way, a color image is recorded with ink on C1M, Y, on both sides, and image signals related to C to K are transferred to the lock CLK.
It is manually input to the image signal distribution bag layer 20 in synchronization with the
When the instruction to use a transparent recording medium is not given and the notification signal A is "0", each distribution circuit 20C to 20K
From there, the image signal is transferred only to the drive device 8 side. On the other hand, when the above instruction is given and the notification signal A is "1", the image signal sent in synchronization with the clock CLK is
Since the switching elements in the distribution circuits 20C to 20 are switched by the clock, every other pixel is distributed and transferred to the drive device 8.9.

Here, by appropriately configuring the distribution circuits 20C to 20, etc., the switching state of the signal path is reversed between the even numbered one and the odd numbered one in the row direction or column direction. It is also possible to form pixels in a staggered pattern or a reverse staggered pattern on the front side and the back side. Also, when focusing on a certain pixel, there is C on the surface side of the recording medium.
It is also possible to eject 1M ink and eject Y, 2 ink on the back side, and to reverse this for adjacent pixels.

The present inventors used recording Δ, rad, and ink similar to those in the first embodiment described above, and used 10 μm of PVA resin on both sides of a 70 μm thick PET film as a recording medium.
M is coated, and PE with a particle size of about 2 μm is coated on the outside.
When we created and used a so-called heat-transparent recording medium in which the PE layer was coated with 20 μm particles and was made transparent by applying pressure and heating after recording, it was found that image signals were not distributed. C, M, Y only on the front side
.

Compared to recording a color image with K ink, it is better to distribute the image signal and record a color image on both sides with C, M, and Y ink, since it is easier to record an image of the same density due to ink overflow, etc. High quality images were obtained with no image deterioration. Furthermore, by performing double-sided recording, it is possible to obtain an image with an overall higher density (almost twice as high), so even if a large amount of ink is applied, it is possible to obtain a high-density, high-quality image with little image deterioration. It was done.

In each of the above embodiments, the image signal distribution circuit (10, 20) indicates that a transparent recording medium is used.
Any form of means for manually applying this may be used.

For example, the notification device 30 may be provided in place of the LED lamp 6 and photoelectric conversion device 7 in FIG. 1, and the LED lamp 6 and photoelectric conversion device 7 may be provided in FIG. The type of ink color and the number of ink colors to be used can be determined as desired. For example, monochrome recording may be performed.

Furthermore, the recording head may be one that is applied to a serial printer type device or a so-called full multi-type one that is applied to a line printer type device.

In addition, there are not only those that record images by moving a recording medium, but also those that record images by moving an inkjet recording head, which is a liquid ejection means, or those that record images by moving both the recording medium and the inkjet recording head appropriately. The present invention can also be effectively applied to devices that record images.

In addition, in the above embodiments, a type of recording medium with coating layers on both sides was used, but if an ink with high drying properties (for example, one containing a large amount of ethyl alcohol) is used, the coating layer can be coated. It is possible to record good images even on transparent recording media without layers.

[Effects of the Invention] As explained above, according to the present invention, the recording heads are arranged on both the front and back sides of the recording medium, and the recording heads are driven according to image signals to form images on both sides of the recording medium. In a liquid jet recording apparatus capable of recording on a transparent recording medium, by providing an image signal distribution means for distributing image signals to two sets of recording head drive devices when recording on a transparent recording medium, it is possible to perform recording on a transparent recording medium as well. It has become possible to record high-density, high-quality images at high speed.

2 is a block diagram showing an example of the positional configuration of image signal distribution in FIG. 1; FIG. 3 is a schematic diagram showing an inkjet printer according to another embodiment of the present invention; FIG. 4 is a block diagram showing an example of the positional configuration of image signal distribution in FIG. FIG. 2 is a block diagram showing an example of a configuration of a sorting device.

1... Front side recording head group, 2...Back side recording head group, 3...recording medium, 6...LED lamp, 7... Photoelectric conversion device, 8.9... Drive device.

10, 20... Image signal distribution device, 11-14.
21-24... Recording head, 30... Notification device.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an inkjet printer according to an embodiment of the present invention;

Claims (1)

[Scope of Claims] 1) In order to perform recording by discharging liquid onto both the front and back sides of a recording medium, a recording head disposed on the front and back sides of the recording medium, and a recording head having a light transmittance or having a light transmittance. When recording on a recording medium to which an image is applied, image signals related to recording are distributed and sent to a recording head placed on the front side of the recording medium and a recording head placed on the back side of the recording medium. A liquid jet recording device comprising a signal distribution means.