JPH09141841A - Ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To apply good printing to all kinds of papers by applying printing to recording paper by a printing head after a precoating material is emitted from a precoating head. SOLUTION: A carriage 23 loaded with an ink cartridge 25 and a precoating cartridge 27 is reciprocally moved in front of recording paper at an equal speed. A printing signal is sent to a voltage applying device for a precoating head from a printing signal generator 28 and voltage is applied to the precoating head 26 to emit precoating liquid droplets 34 to allow them to impinge against the recording paper 32. The printing signal is sent to a voltage applying device 30 for a printing head through a delay circuit 29. Since a delay time is set by the time calculated by dividing the distance between the precoating head 26 and the nozzles of a printing head 24 by the moving speed of the carriage 34, the impinging position of the ink droplets 33 emitted from the printing head 24 to the recording paper 32 becomes the upper part of precoating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-demand type ink jet recording type ink jet printer which ejects ink onto paper for recording.

[0002]

2. Description of the Related Art In recent years, ink jet printers using an ink ejecting device have tended to be colorized and have high image quality, and in order to achieve high resolution, the density of dots landed on recording paper has been increased and the size of the head has been reduced. It is necessary to increase the density and reduce the amount of ejected ink droplets. The conventional inkjet printer will be described below.

FIG. 4 is a partial sectional view of a conventional inkjet head, and FIG. 5 is a sectional view taken along the line AA of the conventional inkjet head shown in FIG. In FIGS. 4 and 5, 2 is a nozzle hole for generating ink droplets 12, 3 is a nozzle plate for forming the nozzle hole 2, 4 is a heater section for heating ink, and a wiring section is not shown, 5 is a heater section Substrate forming 4,
Reference numeral 6 is an ink supply hole for supplying ink from an ink tank (not shown), 7 is a flow path for guiding the ink onto the heater portion 4, 8 is a flow path member forming the flow path 7 and is integrally formed on the substrate 5. Has been done. Reference numeral 9 is a voltage application device for applying a voltage to the heater unit 4 in response to a print signal, 10 is a boiling bubble, 11 is a recording paper, such as plain paper or recycled paper used for printing. As a result, the ink absorptivity changes, so the ink density, bleeding, ink color mixing, and ink dryness greatly differ, and the print quality varies. In order to improve them, there is a coated paper for an inkjet printer, which is coated with a coating solution containing polyvinyl alcohol and finely divided silica on the surface of the paper to improve printing quality. Reference numeral 13 is an adhesive for joining the nozzle plate 3 and the flow path member 8.

FIG. 6 is an assembly diagram of a conventional ink jet head in an ink cartridge. Reference numeral 14 is an ink cartridge equipped with an inkjet head.

FIG. 7 is a partial sectional view of a conventional ink cartridge. Reference numeral 15 is an ink tank provided in the ink cartridge 14, 16 is a filter for removing dust contained in the ink in the ink tank 15, and 17 is an ink introduction groove.

FIG. 8 is a partial sectional view of an ink jet printer having an ink cartridge 14 incorporating a conventional ink jet head. Reference numeral 18 is an ink cartridge insertion opening that serves as an entrance when the ink cartridge 14 is mounted in the printer, 19 is a carriage that fixes the inserted ink cartridge 14, 20 is a guide shaft that guides the carriage 19 that reciprocates serially, and 21 is recording paper. It is a platen roller for sending 11.

The operation of the ink jet printer configured as described above will be described below. The ink is rapidly heated by the heat generated by energizing the heater part 4, and the ink in the flow path 7 is pressured by the generation of the boiling bubbles 10 and flows into the nozzle hole 2. Flows out from the nozzle hole 2 to the outside air, forms an ink droplet 12 due to the surface tension of the ink, and adheres to the recording paper 11. On the other hand, the foamed boiling bubble 10 is cooled by the ink and the volume thereof is rapidly reduced. The ink is refilled through the ink supply hole 6 and the flow path 7 due to the negative pressure generated at that time and the surface tension of the ink.

By repeating the above operation, the ink cartridge 14 mounted on the carriage 19 inserted from the ink cartridge insertion port 18 reciprocates along the guide shaft 20 in response to a print signal sent from a computer or the like. Then, the voltage application device 9 applies a drive voltage to an arbitrary heater portion 4 in accordance with the position of the carriage 19, and droplets 12 are continuously generated, and the platen roller 2
1 is attached to the recording paper 11 sent by 1 and printing by dots is performed.

[0009]

However, the above-mentioned conventional configuration has a problem that the printing quality greatly varies depending on the kind of the recording paper 11 and the ink absorbency.

An object of the present invention is to solve the above-mentioned conventional problems and to provide an ink jet printer capable of excellent printing on all kinds of paper.

[0011]

In order to solve the above problems, the present invention provides a print head for discharging ink from a plurality of nozzle holes according to a print signal to print on a recording paper, and a plurality of print heads according to a discharge signal. It has a precoat head that discharges a precoat material from a nozzle hole to precoat the recording paper, and prints after discharging the precoat material onto the recording paper.
With this configuration, it is possible to obtain an inkjet printer that can perform excellent printing on all types of paper.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention comprises a print head for ejecting ink from a plurality of nozzle holes in response to a print signal to perform printing on a recording paper, and a plurality of print heads for ejecting signals. It has a precoat head that discharges the precoat material from the nozzle hole to precoat the recording paper, and prints after discharging the precoat material to the recording paper.Printing is performed after precoating the recording paper. It has the effect that

The invention according to claim 2 is the same as the invention according to claim 1, in which the precoat material contains polyvinyl alcohol, and has an effect of improving print quality.

According to a third aspect of the invention, in the first aspect of the invention, the ink is a water-based ink and has an effect of being safe.

According to a fourth aspect of the invention, in the invention of the fourth aspect, the landing position of the precoat material ejected by the precoat head on the recording paper and the print head ejects in response to the print signal. It is provided with a control means for controlling a discharge signal for discharging the precoat material so that the landing position of the ink on the recording paper becomes the same position, and the coating material and the ink are discharged to the same position on the recording paper. This has the effect of reducing the amount of coating material used.

According to a fifth aspect of the present invention, in addition to the first aspect of the invention, the ejection amount of the precoat material is set so that the dot size of the dot material of the precoat material landing on the recording paper becomes larger than the dot size of the ink. The control means for controlling is provided, and the ink can be ejected onto the coating material, and the printing quality can be reliably improved.

Embodiments of the present invention will be described below. FIG. 1 is a top view of the vicinity of a carriage of an inkjet printer according to the first embodiment of the present invention, and FIG. 2 is a diagram showing printing by the inkjet printer according to the first embodiment of the present invention. FIG. 3 is a diagram showing printing by the inkjet printer according to the second embodiment of the present invention. In FIG. 1, 22 is a platen roller of an inkjet printer, 23 is an ink cartridge 25, and a platen roller 2 equipped with a precoat cartridge 27.
2 a carriage capable of reciprocating in the longitudinal direction, 24 a print head mounted on an ink cartridge 25, 26 a precoat head mounted on a precoat cartridge 27 for discharging a precoat material, 28 a print signal generator, 2
Reference numeral 9 denotes a delay circuit, 30 denotes a print head voltage applying device, and 31
Is a voltage applying device for a precoat head, 32 is a recording paper, 3
Reference numeral 3 is an aqueous ink droplet, and 34 is a precoat droplet. In FIG. 2, 35 is an ink dot and 36 is a precoat dot. In FIG. 3, 37 is an ink dot, 38
Is a pre-coated dot. The ejection principle of the ink and the precoat material, and the structures of the ink cartridge 25 and the precoat cartridge 27 are the same as the ejection principle of the conventional example and the structure of the ink cartridge, and therefore the description thereof will be omitted. In addition, the print head 24 and the precoat head 2
Although not shown, the number of nozzles, the pitch, and the horizontal position of 6 are the same. The operation of the inkjet printer according to the first embodiment of the present invention configured as above will be described. The carriage 23 carrying the ink cartridge 25 and the precoat cartridge 27 reciprocates at the front surface of the recording paper 32 at a constant speed. A print signal is sent from the print signal generator 28 to the precoat head voltage application device 31,
A voltage is applied to the precoat head 26. A precoat material (not shown) containing polyvinyl alcohol as a main material is housed inside the precoat cartridge 27, and when a voltage is applied to the precoat head 26, the precoat droplets 34 are ejected and land on the recording paper 32. Depending on the print signal, for example, pre-coated dots 3 as shown in FIG.
The pattern of 6 is coated on the surface of the recording paper. On the other hand, the print signal is sent to the print head voltage applying device 30 through the delay circuit 29. The delay time depends on the distance between the nozzles of the precoat head 26 and the print head 24 in the carriage 2.
Since it is set by the time divided by the moving speed of 3, the landing position of the ink droplet 33 ejected from the print head 24 on the recording paper 32 is always on the precoat as shown in FIG.

In the first embodiment of the present invention, the precoat head 26 and the print head 24 are ejected with the same print signal. However, as shown in FIG. The same print quality can be obtained by ejecting the solid dots onto the ink dots 37 and superposing the ink dots 37 thereon.

In this embodiment, the serial printer that forms characters by the reciprocating movement of the carriage 23 with respect to the recording paper 32 is described, but the present invention is also effective for a line printer equipped with a line head. Needless to say.

[0020]

As described above, according to the present invention, a print head that ejects ink from a plurality of nozzle holes in response to a print signal to print on a recording paper, and a precoat material from a plurality of nozzle holes in response to an ejection signal. By having a precoat head for discharging and precoating the recording paper, and performing printing after discharging the precoat material on the recording paper, it is possible to improve the deterioration of the printing quality due to the paper quality.

[Brief description of the drawings]

FIG. 1 is a top view of the vicinity of a carriage of an inkjet printer according to a first embodiment of the present invention.

FIG. 2 is a diagram showing printing by the inkjet printer according to the first embodiment of the present invention.

FIG. 3 is a diagram showing printing by an inkjet printer according to a second embodiment of the present invention.

FIG. 4 is a partial sectional view of a conventional inkjet head.

5 is a line A of the conventional inkjet head shown in FIG.
-A sectional view

FIG. 6 is a diagram of a conventional inkjet head incorporated into an ink cartridge.

FIG. 7 is a partial sectional view of a conventional ink cartridge.

FIG. 8 is a partial cross-sectional view of an ink jet printer equipped with an ink cartridge incorporating a conventional ink jet head.

[Explanation of Codes] 22 Platen Roller 23 Carriage 24 Printing Head 25 Ink Cartridge 26 Precoat Head 27 Precoat Cartridge 28 Print Signal Generator 29 Delay Circuit 30 Printhead Voltage Applying Device 31 Precoat Head Voltage Applying Device 32 Recording Paper 33 Ink Drop 34 Pre-coated droplets 35 Ink dots 36 Pre-coated dots 37 Ink dots 38 Pre-coated dots

Claims (5)

[Claims] 1. A print head for ejecting ink from a plurality of nozzle holes in response to a print signal to print on a recording sheet, and a precoat material for ejecting a precoat material from a plurality of nozzle holes in response to an ejection signal to pre-coat the recording sheet. Has a precoat head,
An inkjet printer, which prints after ejecting a precoat material onto a recording paper. 2. The ink jet printer according to claim 1, wherein the precoat material contains polyvinyl alcohol. 3. The ink jet printer according to claim 1, wherein the ink is a water-based ink. 4. The landing position of the precoat material ejected by the precoat head in response to the ejection signal on the recording paper is the same as the landing position of the ink ejected by the print head in response to the print signal on the recording paper. The inkjet printer according to claim 1, further comprising control means for controlling a discharge signal for discharging the precoat material. 5. The ink jet printer according to claim 4, further comprising control means for controlling the discharge amount of the precoat material so that the dot size of the precoat material landed on the recording paper becomes larger than the dot size of the ink.