JPH06171074A - Ink jet recording device - Google Patents

Abstract

PURPOSE:To realize an ink jet recording device of transfer-type which is free from an excess increase in the temperature of a recording head and ink plugging and is capable of ejecting ink stably from a recording head. CONSTITUTION:The ink jet recording device is equipped with a heating mechanism 23 which can freely select a heating direction arranged near a transfer medium 1, and a control mechanism which turns the heating direction of the heating mechanism 23 at least, once or more toward the transfer medium 1 when an ink image formed on the transfer medium 1 is heated, and switches the heating mechanism 23 from a heating direction to a direction where a recording head 2 is not heated at a time other than when the ink image is heated.

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. More specifically, the present invention relates to a transfer type inkjet recording apparatus that forms an ink image on a transfer medium and then transfers the ink image to the recording medium to obtain the ink image on the recording medium.

[0002]

2. Description of the Related Art A transfer type ink jet recording apparatus has a feature that ink jet clogging caused by unintentional contact between recording paper or paper dust and a recording head does not occur, and high reliability can be obtained. As a conventional transfer type ink jet printer, a configuration described in Japanese Patent Laid-Open No. 1-226336 is known.

In these apparatuses, a recording head having a plurality of nozzles is provided on a cylindrical transfer medium with a gap therebetween. After the ink image is formed on the transfer medium by the recording head, the ink image on the transfer medium is dried by a heater, the recording medium is brought into contact with the transfer medium, and the recording medium is pressed from the rear side of the recording medium. The method of transferring the ink image to is used. According to this configuration, the ink image on the transfer medium is not deformed in the transfer process and does not soak into the recording paper. 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.

[0004]

However, the inventors of the present invention experimentally evaluated a conventional method of transferring an ink image dried on a transfer medium to a recording paper, and as a result, when continuous printing was performed, the transfer was performed. It has been found that the residual heat of the heater that heats the ink image on the medium causes a problem of clogging of ink in the recording head and defective ejection of ink from the recording head.

That is, in the configuration disclosed in Japanese Patent Laid-Open No. 1-226336, when the surface temperature on the transfer medium is raised to dry the ink image formed on the transfer medium, continuous printing is performed. , The heater itself accumulates heat. Even when the heater power is turned off in this state, the heating direction is in the direction to continue heating the transfer medium.
The residual heat of the heater keeps heating the transfer medium. As a result, the recording head is excessively heated through the slight gap with the transfer drum. As a result, in the ink in the recording head, water, which is the main solvent of the ink, evaporates from the ejection port of the recording head, and the viscosity of the ink in the recording head begins to increase.
As a result, ink is clogged at the ejection port of the recording head, resulting in frequent ink ejection failure.

The present invention solves this problem, and an object thereof is a transfer type ink jet recording capable of realizing stable ejection of the recording head without ink clogging without excessively raising the temperature of the recording head. To get the equipment.

[0007]

An ink jet recording apparatus of the present invention ejects ink droplets from a recording head to form an ink image on a transfer medium according to input information, and records the ink image from the transfer medium. In an inkjet recording apparatus for transferring onto a medium, a heating mechanism is provided in the vicinity of the transfer medium, the heating direction of which is freely selectable, and the heating direction of the heating mechanism is set when the ink image formed on the transfer medium is heated. A control mechanism for switching the heating direction of the heating mechanism to a direction in which the recording head is not heated, except when the ink image on the transfer medium is heated at least once or more, is provided. .

[0008]

According to the above apparatus, when the ink image formed on the transfer medium by the recording head is heated, the heating direction of the heating mechanism is directed at least once to the transfer medium, and
Since the direction in which the recording head is not heated is shown except when the ink image on the transfer medium is heated, stable ejection of the recording head without ink clogging is realized without excessively increasing the temperature of the recording head. it can.

[0009]

EXAMPLES Examples of the present invention will be described.

FIG. 1 shows a perspective view of a first embodiment of an ink jet recording apparatus.

First, the configuration of this embodiment will be described.

The recording head 2 is an ink jet recording head of a type using a piezoelectric element, and has a plurality of nozzles 40 at regular intervals in the axial direction of the transfer drum 1 which is a transfer medium, as shown in FIG. In this embodiment, the recording head 2 has 512 nozzles 4 at a 16/600 inch pitch.
0, and the recording head 2 moves 1/6 in the direction of arrow B while the transfer drum 1 makes one rotation in the direction of arrow A shown in FIG.
It is a structure that can be moved by 00 inches.

The ink is an ink containing at least water, a water-soluble organic solvent, a pigment, and a colloidal dispersion type resin. Specifically, 3 wt% of carbon black as a pigment, and Watersol CD-540 (resin solid content: 40%, isopropylene glycol: 13%, which is a modified epoxy ester type colloidal dispersion of Dainippon Ink and Chemicals, Inc. as a colloidal dispersion type resin) Content of 30 wt%, triethanolamine 5 wt% as a water-soluble organic solvent, and triethylene glycol 5 wt% as a moisturizer, and pure water. The solid content in the ink refers to pigments such as carbon black and colloidal dispersion type resin, and the solid content particle size at the time of ink production is 1 μm.
It is the following.

The transfer drum 1 has an elastic layer 12 made of silicone rubber around a metal tube 11. In this embodiment, the transfer drum 1 having a diameter of 80 mm is used. Further, the elastic layer 12 is preferably made of a rubber material from which an ink image is easily peeled off. In addition to silicone rubber, fluorosilicone rubber, fluororubber, hydrogenated nitrile rubber, silicone rubber in which a surfactant is kneaded, or the like can be used. .

In order to accelerate the evaporation of water from the ink image on the transfer drum 1 and to dry it quickly, a heating mechanism 23 having a heater lamp 20 composed of a rod-shaped halogen lamp and a reflector 21 for setting a constant heating direction is provided. ing. The heater lamp 20 detects the surface temperature of the elastic layer 12 by a temperature sensor (not shown), and intermittently turns on the surface temperature so that the temperature falls within a predetermined range, so that the temperature of the ink image formed on the transfer drum 1 is reduced. It controls the water vaporization characteristics. That is, the ink image on the transfer drum 1 is dried to a semi-solid state by controlling the temperature within a predetermined temperature range. In this example, the temperature is kept at about 50 ° C. In addition, a tooth profile 22 is provided at the end of the reflector 21 so that the gear 3
By transmitting the driving force of the motor 30 to the tooth profile 22 via 1, the reflector 21 is configured to be rotatable in the arrow D direction shown in the drawing. Furthermore, the fixed position of the reflector 21 can be freely selected by controlling the rotation of the motor 30. In the case of the present embodiment, the heating direction of the heating mechanism 23 is the heating direction position indicated by the arrow S in FIG. 3 toward the axis of the transfer drum 1, and the recording medium which is the recording medium indicated by the arrow T in FIG. 4 are set in three modes, that is, a heating direction position toward the ink image transferred onto the recording medium 4 and a heating direction position 180 degrees opposite to the position of the recording head 2 shown by an arrow U in FIG.

Further, there is provided a backup roller 3 for pressing the recording paper 4 to the transfer drum 1 in order to transfer the ink image formed on the surface of the transfer drum 1 by the recording head 2 to the recording paper 4. The backup roller 3 is
The transfer lever 1 can be pressed or released by a pressing lever 16 having the fulcrum 15 as a swing axis. Further, this pressing force is controlled by the urging force of the spring 17,
The pressing load in this embodiment is 0.28 to 0.6 kg / c.
m.

Next, the operation will be described.

FIG. 3 is a sectional view showing a state in which ink droplets are selectively ejected from the nozzles 40 of the recording head 2 to form an ink image on the transfer drum 1. That is, the backup roller 3 is not in contact with the transfer drum 1 due to the pressing lever 16 swinging in the direction of the arrow E around the fulcrum 15. Further, by rotating the motor 30 in the G direction, the reflector 21 is fixed at a position where the heating direction of the heating mechanism 23 becomes the heating direction S toward the axis of the transfer drum 1.

In this embodiment, the recording head 2 is 16/60.
Since 512 nozzles 40 are provided at 0 inch pitch, an ink image for 512 lines is formed on the transfer drum 1 at 16/600 inch intervals while the transfer drum 1 makes one rotation in the direction of arrow A. it can. At this time, the heater lamp 20 of the heating mechanism 23 is intermittently turned on so that the surface temperature of the elastic layer 12 falls within a predetermined range to evaporate the water content in the ink image formed on the transfer drum 1, and the transfer drum 1 A semi-solid state ink image is formed on top. Further, while the transfer drum 1 makes one rotation, the recording head 2 moves in the direction of arrow B shown in FIG.
/ 600 inch, and then the transfer drum 1 enters the second rotation. As a result, similarly to the first rotation of the transfer drum 1, 512 lines of ink adjacent to the ink image formed in the first rotation of the transfer drum 1 at a 16/600 inch interval in the second rotation of the transfer drum 1 are formed. The image can be formed in a semi-solid state. Similarly, when the transfer drum 1 rotates 16 times, an image for one page formed of an ink image in a semi-solid state is formed on the transfer drum 1. At this time, since the backup roller 3 does not come into contact with the surface of the transfer drum 1, the sequentially formed ink images are not damaged and a high quality image can be obtained on the transfer drum 1.

FIG. 4 shows a transfer drum 1 driven by a recording head 2.
FIG. 6 is a cross-sectional view showing a state in which the transfer of the semi-solid state ink image formed on the recording paper 4 is started. That is, fulcrum 15
The backup roller 3 presses the transfer drum 1 with the urging force of the spring 17 by swinging the pressing lever 16 in the direction of arrow F about the center. Further, by rotating the motor 30 in the H direction, the heating direction of the heating mechanism 23 is directed toward the ink image transferred to the recording paper 4 in the heating direction T.
In this state, the reflector 21 is fixed at the position.

The semi-solid ink image formed on the transfer drum 1 is semi-solid on the recording paper 4 by pressing the recording paper 4 between the backup roller 3 and the transfer drum 1 with the biasing force of the spring 17. It is glued as it is. Next, transfer drum 1
The recording paper 4 moves with the rotation of, and the ink image is separated from the elastic layer 12 of the transfer drum 1 at the interface. After that, the heating mechanism 23 dries the ink image on the recording paper 4 until it becomes a solid state, and fixing of the ink image on the recording paper 4 is completed.

The urging force of the spring 17 required for transfer is determined by the dry state of the ink image formed on the transfer drum 1. That is, when the ink image on the transfer drum 1 is completely dried and in a solid state, the adhesive force between the ink image formed on the transfer drum 1 and the elastic layer 12 becomes very high, and the transfer pressure of high load is applied. In addition, the transfer failure to the recording paper 4 is likely to occur frequently. On the other hand, by drying the ink image on the transfer drum 1 to a semi-solid state as in the present embodiment, the adhesive force between the ink image on the transfer drum 1 and the elastic layer 12 is lowered, and the ink image is reduced. Since the adhesive force between the recording paper 4 and the recording paper 4 becomes high, it is possible to realize the transfer to the recording paper 4 with no transfer residue with a low weighted transfer pressure.

However, since the ink image transferred onto the recording paper 4 is in a semi-solid state, it is inferior in rubbing resistance such as rubbing when touched by hand and water resistance such as water resistance. Therefore, in this embodiment, the heating mechanism 23 is used to dry the ink image transferred to the recording paper 4 to a solid state to improve the fastness.

FIG. 5 is a cross-sectional view showing a standby state after discharging the recording paper 4 after transfer. That is, the backup roller 3 is not in contact with the transfer drum 1 due to the pressing lever 16 swinging in the direction of the arrow E around the fulcrum 15. Further, by rotating the motor 30 in the H direction, the reflector 21 is fixed at a position where the heating direction of the heating mechanism 23 is 180 ° opposite to the position of the recording head 2 shown by the arrow U.

When continuous printing is performed, the heating mechanism 23 after heating the ink image formed on the transfer drum 1 or the heating mechanism 23 after heating the ink image transferred onto the recording paper 4 is heated. Is in the accumulated state. As a result, the residual heat of the heating mechanism 23 continues to be emitted from the heating direction even when the power of the heating mechanism 23 is turned off. At this time, if the heating direction indicates the direction of heating the recording head 2, for example, the direction toward the axis of the transfer drum 1 of this embodiment, the residual heat of the heating mechanism 23 is the residual heat of the transfer drum 1 surface. Will continue to be heated, and the transfer drum 1 and the recording head 2 will be heated.
Is a slight gap (about 0.5 mm to 1 mm in this embodiment)
The temperature of the recording head 2 continues to rise because it is located only through the. As a result, the water, which is the main solvent of the ink in the recording head 2, continues to evaporate from the nozzles 40, the viscosity of the ink in the recording head 2 begins to increase, and clogging of the recording head 2 and defective ink ejection occur frequently. Become. However, in the case of the present embodiment, when the heating mechanism 23 accumulates heat and generates residual heat, the heating direction is 180 ° opposite to the position of the recording head 2 shown by the arrow U in FIG. Since the transfer drum 1 and the recording head 2 are not continuously heated by the residual heat of the mechanism 23,
It is possible to prevent ink clogging and defective ink ejection.

[0026]

According to the ink jet recording apparatus of the present invention,
A heating mechanism in which the heating direction can be freely selected is provided near the transfer medium, and the heating direction of the heating mechanism is directed to the transfer medium at least once when the ink image formed on the transfer medium is heated. Except when the ink image is heated, the control mechanism that switches the heating direction of the heating mechanism to the direction that does not heat the recording head does not cause ink clogging without raising the temperature of the recording head excessively and stabilizes. The ejection of the recording head can be realized.

[Brief description of drawings]

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

FIG. 2 is a plan view showing a nozzle surface of a recording head used in the inkjet recording apparatus of the first embodiment.

FIG. 3 is a cross-sectional view showing a writing state on a transfer medium.

FIG. 4 is a cross-sectional view showing a transfer state to a recording medium.

FIG. 5 is a cross-sectional view showing a standby state of the inkjet recording apparatus.

[Explanation of symbols]

 1: Transfer drum (transfer medium) 2: Recording head 3: Backup roller 4: Recording paper (recording medium) 11: Metal tube 12: Elastic layer 20: Heater lamp 21: Reflector 22: Tooth profile 23: Heating mechanism 30: Motor 31: Gear S, T, U: Heating direction

Claims (1)

[Claims] 1. An ink jet recording apparatus for ejecting ink droplets from a recording head to form an ink image on a transfer medium according to input information, and transferring the ink image from the transfer medium to the recording medium. A heating mechanism in which the heating direction is freely selectable in the vicinity of, and the heating direction of the heating mechanism is directed to the transfer medium at least once when the ink image formed on the transfer medium is heated, An inkjet recording apparatus comprising a control mechanism for switching a heating direction of the heating mechanism to a direction in which the recording head is not heated except when the ink image on the medium is heated.