JPS61219653A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To prevent defective printing from occurring, even after operation is stopped for a long period of time, by a method wherein a feeding means is operated before starting recording so as to feed an ink support member by a length corresponding to the distance between a position for making contact with an ink-supplying means and a position for making contact with heating elements. CONSTITUTION:The heating elements are selectively driven according to a recording signal to eject an ink. After the ejection is finished, a carriage 3 is moved rightward a predetermined distance. Concurrently with the movement of the carriage 3, a film 1 is fed leftward, whereby a hole part filled with a fresh ink is again supplied to a thermal head 4. At this time, an unused portion of the ink is recovered by a film cleaner 8 provided on the downstream side of the head 4, and the film 1 is taken up into a film cassette 2 in the state wherein no ink is left in the holes. After the movement of the carriage 3 is finished, the heating elements are again selectively driven to eject the ink. These operations are repeated, and printing is finished when the carriage 3 comes to the right end of a recording paper 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an inkjet recording device, and more particularly to an inkjet recording device that performs recording by applying heat to liquid ink and causing the ink to fly.

[Technical background of the invention and its problems]

In the so-called inkjet recording method, which prints on recording paper by ejecting minute ink droplets from a capillary nozzle (orifice), the pressure of the ink liquid is instantaneously increased using the vibration of a piezoelectric element within the orifice. Means for ejecting ink from a nozzle (Japanese Patent Application Laid-open No. 1983-9622)
Alternatively, a method has been proposed (Japanese Patent Publication No. 56-9429) in which a heat generating element is provided in the ink character (orice) to generate air bubbles in the ink chamber to increase the pressure of the ink liquid and cause the ink to be ejected from all nozzles. has been done. These are called on-demand methods that eject ink only when needed, and have the advantage of not wasting ink and relatively fast recording speeds. The production of the recording head is complicated, including the arrangement of elements and heating elements, and there is a major problem in that the ink liquid solidifies when the apparatus is stopped, causing clogging and malfunction. This problem has not been fundamentally solved because there are many conflicting factors in preventing clogging, such as reducing the nozzle diameter, while there is a demand for higher density recording. On the other hand, as a means to perform recording by spraying ink without using such a nozzle, there is a method disclosed in Japanese Patent Application Laid-open No. 51-1.
As disclosed in No. 32036, a heating element is provided below the surface of the ink liquid and rapid heating is performed to generate bubbles, and the impact caused by the bursting of the bubbles causes ink droplets to fly from the liquid surface. A method is proposed. Although this method essentially does not cause the problem of ink clogging, it does have problems such as environmental pollution due to ink evaporation, limitations in the equipment configuration, ink spillage during transportation and movement, and problems with image quality. In particular, it is difficult to maintain a constant distance between the ink surface and the heat-generating portion, so the state of the ink droplets tends to become unstable, which is unsatisfactory.

In order to eliminate these drawbacks of conventional inkjet recording devices, ink is supplied from an ink supply means to a film having minute holes or recesses, and this is brought into contact with a heating element of a thermal head to drive one heating element and generate heat. An inkjet recording device was proposed (Japanese Patent Application No. 58-178201) in which the ink in the abutting holes or recesses is caused to fly toward the recording paper using bubble pressure. Instead of one ink ejection port, a plurality of ink ejection ports correspond to the energy source, and ink clogging is significantly reduced. However, even with this device, if printing is stopped for a long time, the ink in the holes or recesses in the film between the ink supply means and the printing section may dry up and cause printing defects when printing starts. was there.

[Purpose of the invention]

This invention improves the above-mentioned drawbacks, and provides an inkjet recording device with excellent reliability that does not cause printing defects due to ink clogging even when the operation is stopped for a long period of time without adding any special structure. The purpose is to provide.

[Summary of the invention]

The present invention provides an ink retaining means, such as a film, having a large number of micropores or microrecesses for retaining ink.

an ink supply means that contacts the ink holding member and supplies ink; a conveying means that transports the ink holding member; and a means that contacts the ink holding member that holds the ink and selectively applies thermal energy. Equipped with a thermal head having a heating element.

An inkjet that records on a recording paper provided to face the thermal head while holding the ink retaining member by causing the ink retained in the ink retaining means to fly by thermal energy applied by the thermal head. In the recording apparatus, when the start light is applied to this recording, the conveying means carries ink at least by the length between the position where the ink retaining member abuts the ink supply means and the position where the ink retaining member abuts the heating element of the thermal head. An inkjet recording device is provided that is characterized by conveying a holding member.

〔Effect of the invention〕

In the present invention, since the ink holding means is transported to a predetermined position prior to the start of recording, good recording can always be performed regardless of the length of the operation stop period, and in particular, recording defects at the beginning of recording can be eliminated.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 2 shows a schematic configuration of a serial printer.

1 is a perforated film with a thickness of 8 μfn to 100 μm made of metal such as nickel, aluminum, and stainless steel, plastic with excellent heat resistance such as polyimide, fluororesin, polypropylene, and polyester, or a laminate of metal and plastic. Fine pores of 10 μm to 200 μm are formed at high density. The pore size and pore formation density are related to the size of the heating element used. In other words, the pore diameter and pore formation density are determined so that on average two or more pores come into contact with the heating element.For example, in the case of a heating element of 100μ, a polyimide film with a thickness of 15μ has a hole diameter of 20
It is sufficient to form the circular holes of μ in total at a density of about 1000/-, and in this case, one heating element corresponds to about 25 holes on average. Here, a 40μ thick polyimide film with a thickness of 20μ is used.
(diameter) with a hole density of approximately 500 holes/-5
2 is a film cassette having two reels, the difilm 1 is supplied to one reel and taken up by the other reel.

The film may also have an endless configuration. The film cassette 2 is configured to be detachable from the carriage 3, and when the film is wound onto one reel, the cassette 2t can be turned over and used repeatedly. 4 is a thermal head, and a thermal head 1 is installed on the surface that contacts the filmer 1 in a direction perpendicular to the scanning direction of the carriage 3 (indicated by the arrow).
Twenty 220μ0 heating elements (not shown) are provided in a row at a density of 4 elements/deaf. These heating elements are selectively driven and generate heat according to recording signals by a thermal head driving circuit (not shown). 5 is an ink supply means;
It consists of a sponge 6 and an ink tank 7 storing black ink. A film cleaner 8 collects ink remaining on the film after printing. 9 is recording paper, which is PPC paper. Paper materials such as high-quality paper and medium-quality paper, or plastic sheets such as polyester sheets can also be used. 5 10 is a platen roller, which is a rubber roller. 11 is a motor for driving the platen, and 12 is a motor for driving the carriage, which is connected to the carriage 3 by a belt 13. The recording principle of this printer will be explained using FIG. 2. FIG. 2 is a diagram showing a recording section of a printer. A perforated film 14 is conveyed, and holes 1 that are not filled with ink are shown.
5 comes into contact with a sponge pad 16, which is an ink supply means, and ink is supplied into the hole. The hole 17 filled with ink is further transported to a thermal head 18 which is a printing means. Heat generating element of thermal head 18 (not shown)
is selectively energized according to recorded information. Due to the rapid temperature rise of the heating element, air bubbles are generated in the holes filled with ink that come into contact with the heating element.

Ink is ejected from the holes due to the action of rapidly growing and expanding bubbles. The ejected ink 19 flies toward the recording paper 20, forming an ink image 21? Form.

In this recording apparatus, ink is used by filling holes in a film, which is an ink carrier, by an ink supply means. Therefore, when the printing operation is stopped, the film between the ink supply means and the thermal head is always left with the holes filled with ink.

Therefore, if the ink is left for a long time, the ink will evaporate and only adhere to the area around the holes in the film, resulting in poor printing in this area (shown in the figure).

Next, the operation of this printer will be explained. When power is turned on for printer operation, the carriage 3 is moved by the action of the motor 12 from the home position to the printing start position. During this transfer ηb, the thermal head 4 and the ink supply means 5
The film 1 in between is fed until the part that was in contact with the sponge 6 passes through the thermal head 4. As a result of this film transport, the ink supply means 5 supplies the hole portion of the film newly and sufficiently filled with ink to the bottom of the thermal head 4 . Thermal head drive circuit (
(not shown), the heating element (not shown) responds to the recording signal.
(not shown) are selectively driven to eject ink. When the discharge is completed, the carriage 3 is moved by a predetermined distance to the right by the action of the motor 12. As the carriage 3 moves, the film 1 is fed 250μ to the left, and the hole filled with new ink is placed in the thermal head 4.
F is supplied again. At this time, the unused ink is collected by the film cleaner 8 provided on the F flow side of the thermal head 4, and the film is wound into the film cassette 2 in the hole ((in the state without ink). After that, the heating elements are selectively driven again to eject ink.This operation is then repeated until the carriage 3 reaches the right end of the recording paper 9, completing printing for one line.Then, the carriage 3 is driven by the motor 12. The recording R19 is moved back to the printing start position by the action of the motor 11.During this time, the record R19 is fed by one line following the platen row 210, which is rotated by a predetermined amount by the action of the motor 11.The following five or more operations are repeated. Introducing one-page printing.

When the printer, which does not advance the film, was stopped for two weeks before starting printing, there were many missing dots at the beginning of printing, and the quality of each character was extremely deteriorated. When the printer was stopped for another month and printing was performed, the first part of the printing could not be printed at all. On the other hand, the printer according to the present invention was able to perform good printing from the beginning even after stopping for two weeks and one month.

In the printer of the embodiment, the film was advanced when the carriage was moved from the home position to the print start position in synchronization with the power being turned on to the printer, but it may be performed at the home position or while waiting at the print start position. It's okay. Also, the timing of film feeding may be such that even if the power is being turned on, the film feeding may be carried out after the printing operation has been stopped for a certain period of time.

The inkjet recording apparatus according to the present invention is not limited to the serial printer in the embodiment, but can also be applied to a line printer using a line type thermal head. Furthermore, it goes without saying that the present invention can be applied not only to monochrome printers but also to color printers.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a 1-ton serial printer according to an embodiment of the present invention, and FIG. 2 is a diagram for explaining the recording principle of the recording apparatus of the present invention.

Claims (1)

[Claims] an ink retaining member having a large number of microholes or microrecesses for retaining ink; an ink supply means for supplying ink by contacting the ink retaining member; a conveying means for conveying the ink retaining member; and a thermal head having a heating element that contacts an ink holding member holding the ink holding member and selectively applies thermal energy, and the thermal energy applied by the thermal head causes the ink held in the ink holding member to fly. In an inkjet recording apparatus that records on a recording paper provided to sandwich the ink retaining member and face the thermal head, prior to the start of recording, the conveying means is configured such that at least the ink retaining member is supplied with the ink. An inkjet recording apparatus characterized in that the ink holding member is conveyed by a length between a position where it contacts the means and a position where it contacts a heating element of the thermal head.