JPH04140144A - Ink jet printer - Google Patents

Abstract

PURPOSE:To heighten the drying effect on ink forming an image on a printing medium by providing a paper heating means on the upstream side of a print head on a paper running path for the printing paper and in a position close to the print head. CONSTITUTION:A printing paper 5 held between a feed roller 3, which is driven by a driving means, and a pressure roller 4, whose drive follows after that of the feed roller 3, is fed to paired heater rollers 7. One of the paired heater rollers 7, which contacts with the printing face side of the printing paper 5, generates heat by power supplied by a drive circuit and pressurizes the printing paper 5 by an urging means to heat said paper simultaneously. Thereupon, ink droplets are discharged from the nozzle of an ink jet print head 1 onto the heated printing paper 5 to form an image thereon. Liquid ink stuck onto the surface of the printing paper 5 is then dried by heat that the printing paper itself has. Further, a heat roller 11 of the paired heater rollers 7, which contains a heater means, has a heater lamp 12 therein and is so constituted that power is supplied to the heater lamp by the drive circuit through a lead wire 13 to generate heat.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to the structure of an inkjet printer.

[Conventional technology]

Conventionally, in this type of inkjet printer, as shown in FIG.
A heater 7 that generates heat when energized is arranged on the downstream side of the heater 7 to heat the printing paper 5 after image formation while conveying the paper without contact, thereby removing the liquid ink on the surface of the printing paper 5 on which the image has been formed. , a drying method is used.

[Problems to be Solved by the Invention] As described above, conventional inkjet printers have an inkjet printer installed on the downstream side of the carriage means on the conveyance path of the paper conveyance means in order to dry the liquid ink on the surface of the printing paper after image formation. It is configured to include heater means. For this reason, depending on the type of printing paper, the ink ejected from the nozzle of the inkjet print head and attached to the surface of the printing paper may penetrate more than necessary in the thickness direction by the time it dries, resulting in poor printing. It has the fatal disadvantage of reducing the reflection density of the image or spreading the surface layer of the printing paper in the plane direction, causing "feathering" and "bleeding", which significantly impairs the quality of the printed image. was.

(Objective of the Invention) An object of the present invention is to provide an inkjet printer that improves the quality of printed images by reducing the occurrence of feathering, bleeding, etc., and improving the disadvantages of the conventional example. do.

[Means to solve the problem]

In the present invention, an inkjet print head having a plurality of small-diameter nozzles, a carriage means for reciprocating this print head in a predetermined direction, and a printing paper disposed opposite to the print head are used to print the print head. In an inkjet printer equipped with a paper conveyance means that causes the paper to travel in a direction perpendicular to the direction of movement of the head,
A configuration is adopted in which a paper heating means is provided on the upstream side of the print head in the paper running path for printing paper, close to the print head. This aims to achieve the above-mentioned purpose.

[First Embodiment] Hereinafter, a first embodiment of the present invention will be described based on FIGS. 1 and 2.

In FIG. 1, an inkjet print head 1 having a plurality of micro-diameter nozzles is mounted on a carriage that faces a printing paper 5 and performs linear reciprocating motion (in this figure, reciprocating motion in the front and back directions of the paper surface). The feed roller 3 and the pressure roller 4 form a paper conveying means that conveys the printing paper 5 in a direction perpendicular to the reciprocating direction of the carriage 2 while holding the printing paper 5 under pressure. On the upstream side of the carriage 2 on this paper conveyance path, there are two sheets having a length that can press and hold the printing paper 5 over the entire width of the image forming range, and which are pressed against each other with a predetermined pressure and contact the printing surface side of the printing paper 5. The rollers include a pair of heater rollers 7 which incorporate heater means that is energized and generates heat by a drive circuit (not shown), and are rotationally driven by a drive means (not shown). Further, the platen 8 is arranged to face the inkjet print head 1 and holds the print paper 5 together with a paper guide mechanism (not shown) during a printing operation, and maintains the inkjet print head 1 and the print paper 5 at a predetermined gap.

Furthermore, in order to convey the printing paper 5 on which an image has been formed by the inkjet print head 1, a pair of rollers 6 are provided on the downstream side of the carriage 2 on the paper conveyance path, and are pressed against each other with a predetermined pressure and are rotationally driven by a driving means (not shown). have.

Next, the operation will be explained step by step.

Feed roller 3 driven by a driving means (not shown)
The printing paper 5 is sandwiched between the pressure roller 4 and the pressure roller 4 following the printing paper 5 and is conveyed to a pair of heater rollers 7 . The roller of the pair of heater rollers 7 that is in contact with the printing surface side of the printing paper 5 is energized by a drive circuit (not shown) to generate heat, and the printing paper 5 is pressurized and heated at the same time by a biasing means (not shown). The heated printing paper 5 is further conveyed to the inkjet printhead 1, and the inkjet printhead 1 emits ink droplets from its nozzles while being scanned by the carriage 2 in a direction perpendicular to the printing paper conveyance direction based on the print image information. An image is formed on the ejected printing paper 5. The liquid ink adhering to the surface of the heated printing paper 5 at this time is dried by the heat of the printing paper itself before it penetrates or diffuses into the printing paper 5 more than necessary.

The printing paper 5 on which image formation has been completed is held between a pair of rollers 6 and conveyed to the outside of the apparatus or to another post-process.

Here, of the pair of heater rollers 7, the roller having a built-in heater means is made of an electrically conductive heat generating member such as a tungsten wire inside a thin cylindrical heat roller 11 made of a metal such as aluminum, as shown in FIG. It has a heater lamp 12. The heater lamp 12 is configured to be energized by a drive circuit (not shown) through a lead wire 13 to generate heat.

Here, the contact-type heater roller pair 7 can essentially be configured to heat either the front or back side of the printing paper 5, but it is more efficient to heat the printing surface side.

In addition, in order to minimize the temperature drop until the print paper 5 heated by the heater roller pair 7 is conveyed to the inkjet print head 1, the heater roller pair 7 is moved as far as possible to the inkjet print head 1 in the paper conveyance direction. It is more effective if they are placed close together.

In this way, in the first embodiment, a length is provided on the upstream side of the carriage means on the conveyance path of the paper conveyance means so that the print medium can be pressurized and heated at the same time over the entire width of the image forming range, and the length is energized. By providing a pair of heater rollers that generate heat by heating the printing medium immediately before inkjet recording, the printing medium is pressurized and heated at the same time.This dramatically improves the drying effect of the image forming ink on the printing medium, resulting in high-density feathering and It is possible to provide a high-quality printed image without bleeding.

[Second example] Next, a second embodiment will be described based on FIG.

The second embodiment shown in FIG. 3 is characterized in that a non-contact type heater 17 is used in place of the heater roller pair 7 (see FIG. 1) used in the first embodiment described above. are doing. In this case, in the embodiment shown in FIG. 3, the heater 17 is installed separately from the platen 8, but
The configuration may be such that the heater 17 is provided integrally with the platen 8 on the upper side of the paper. The rest of the structure is the same as the embodiment shown in FIG. 1 described above.

Even in this case, in addition to having the same function and effect as the embodiment shown in FIG. It has certain characteristics.

[Third Embodiment] Next, a third embodiment will be described based on FIGS. 4 and 5. The embodiment shown in FIGS. 4 and 5 uses a character drying roller pair 27 in place of the heater roller pair 7 (see FIG. 1) used in the first embodiment, and The printer is characterized in that the pair of drying rollers 27 is provided downstream of the paper travel path when viewed from the print head 1.

In this case, the character drying roller pair 27 includes, as shown in FIG. It is composed of an absorbent layer.

Reference numeral 17C indicates a metal shaft 27C as a rotating shaft attached to the central shaft portion of the roller body 27A. As for the other character drying roller, one having a similar structure is used in this embodiment, but it may have another structure.

The other configurations are the same as the conventional example described above.

Even in this case, substantially the same operation and effect as each of the embodiments described above can be achieved.

〔Effect of the invention〕

As described above, according to the present invention, the upstream side of the carriage means on the conveyance path of the paper conveyance means has a length that can pressurize and simultaneously heat the print medium over the entire width of the reimage formation range.
Since it is equipped with a pair of heater rollers that generate heat when energized and is configured to pressurize and heat the printing medium immediately before inkjet recording, it is possible to dramatically improve the drying effect of the image forming ink on the printing medium. It is possible to provide an unprecedented inkjet printer that can obtain high-quality printed images with high density and no feathering or bleeding.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing the first embodiment of the present invention, and FIG.
The figure is an explanatory diagram showing the heat roller of the heat roller pair in Figure 1, and Figure 3 is an overall configuration diagram showing the second embodiment.
FIG. 4 is an overall configuration diagram showing the third embodiment, and FIG. 5 is a diagram showing the fourth embodiment.
An explanatory diagram showing an example of the drying roller used in the diagram,
FIG. 6 is a configuration diagram showing a conventional example. 1...Ink end type print hand, 2.
... Carriage means, 3 ... Feed roller, 4 ... Pressure roller, 5 ...
・・Printing paper, 6・・Roller pair, 7−・−・−
Heater roller pair, 11... Heat roller, 2... Heater lamp, 7... Heater, 27... Character drying roller pair.

Claims (5)

[Claims] (1) An inkjet print head having a plurality of small-diameter nozzles, a carriage means for reciprocating this print head in a predetermined direction, and a printing paper disposed opposite to the print head. In an inkjet printer, the inkjet printer is equipped with a paper conveying means for running in a direction perpendicular to the moving direction of the print head, and a paper heating means is provided on the upstream side of the print head in the paper running path for the printing paper and close to the print head. An inkjet printer characterized by being equipped with. (2) The paper heating means is equipped with a heater having a length capable of heating the entire width of an image forming area on the printing paper, and is installed in close proximity to the printing paper without contacting it. The inkjet printer according to claim 1. (3) The paper heating means is constituted by a pair of heater rollers having a length sufficient to heat the entire width of the image forming area on the printing paper, and at least one side of the pair of heater rollers that contacts the printing surface of the printing paper. An inkjet printer characterized in that the heater roller includes a roller body with good thermal conductivity and a heater lamp housed within the roller body. (4) an inkjet print head having a plurality of small-diameter nozzles; a carriage means for reciprocating this print head in a predetermined direction; and a printing paper disposed opposite to the print head. In an inkjet printer, the inkjet printer is equipped with a paper conveyance means for running in a direction perpendicular to the movement direction of the print head, and a paper conveyance means for drying characters is provided on the downstream side of the print head in the paper running path for the print paper, and is adjacent to the print head. An inkjet printer characterized by being equipped with an ink character drying means consisting of a pair of rollers. (5) The character drying roller pair is formed to have a length spanning the entire width of the image forming area on the printing paper, and at least the characters on the side of the character drying roller pair that come into contact with the printing surface of the printing paper. 5. The inkjet printer according to claim 4, wherein the drying roller has an ink absorbing layer on its outer periphery.