JPS6048366A - Ink jet recording apparatus - Google Patents

Abstract

PURPOSE:To obtain high density sharp recording even to a light pervious recording medium, by changing the number of ink liquid droplets forming one picture element by a change-over switch. CONSTITUTION:An up-down counter 31 counts up in synchronous relation to the clock from CPU30 at the time of forward printing and a data address corresponding to the count value thereof is calculated through an address decoder 32. Dot recording is performed according to data 35 through an ink jet unit 38. The counter 31 is used as a down counter at the time of backward printing and data is taken out in synchronous relation to the clock in contrast with the forward printing and backward printing is performed. The data of RAM33 is succeedingly held until reciprocal printing is performed only over the initially determined number of times and paper feed by a paper feed mechanism 41 is not also performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an inkjet recording apparatus, and more particularly to an inkjet recording apparatus that performs recording by ejecting ink droplets onto a recording medium according to recording information.

[Prior Art] Conventionally, it has been known that the recording quality (print density, dot shape after printing, etc.) of this type of recording apparatus is greatly influenced by the physical properties of the recording medium. Therefore, in any recording device, it is recommended to use paper recommended for inkjet printers, such as a type of special paper, and the current situation is that the desired print quality can be obtained when using this paper.

Recommended paper has finely determined physical properties such as diffusion isotropy, diffusion speed, adsorption speed, and reflection density of the droplets printed on it. When recording by loading film for a projector (hereinafter referred to as OHP), the quality of the print may deteriorate significantly due to differences in the physical properties of the recording medium, or in severe cases, the print may not be fixed. there were. Therefore, attempts have been made to surface-treat OHP films and form a thin film of gelatin or PVA on the surface layer to improve fixing properties.

However, the improvement in fixing properties does not necessarily mean that the characteristics of OHP films have been improved in all respects, and they also have the major drawback of low printing density due to the fundamental difference in physical properties from plain paper described below. .

That is, OHP films, unlike paper, have low diffusivity (that is, dot spread is small), and improved fixing performance also means a decrease in the diffusivity of OHP films. Therefore, when such an OHP film is loaded into a conventional Infusiera printer and recorded, the dot of each pixel becomes small, resulting in a decrease in printing density and a blurred recording with pale colors. That is, in the case of an OHP film as shown in FIG. 2, the dot diameter 3 ejected into one pixel area 1 is smaller than the dot diameter 2 in the case of plain paper shown in FIG.

Furthermore, OHP films transmit light, while conventional recording paper uses the reflected light to express images, so even ink with relatively low ink density is colored throughout (the dots are diffused). (larger and less background)
Even if the reflection density and ink density are not that low, when looking at an object with wide dot spacing and small dot diameter using transmitted light, the reflection density is better than the ink density. If the concentration is increased, there are problems such as clogging when left for a long period of time, dye precipitation, etc., and there is a problem that the dye cannot be increased beyond a certain concentration.

Also, ink is ejected multiple times to form one pixel.
There are ways to improve the recording density on P film, but when recording on plain paper, a large amount of ink is ejected, resulting in problems such as decreased resolution, ink leakage, and wrinkles on the recording paper. Further, since ejection is performed multiple times for one pixel, the recording speed is reduced.

[Objective] Therefore, the present invention aims to eliminate such conventional drawbacks, and is intended to provide a light-transmissive recording medium such as an OHP film.

[Example] Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

In the inkjet recording apparatus according to the present invention illustrated in FIG. 3, the reference numeral 11 is a power switch;
In addition, by opening the upper cover 12, the release lever 1
3, a light-transmissive recording medium such as plain paper or OHP film can be loaded. Further, an operation knob 15 is provided on the front surface, and the operator performs recording operations via this operation knob. There is also a switch 1 for switching between recording on OHP film and other recording media.
4 is provided.

Further, the recording device according to the present invention can record Y (yellow), M (magenta), C (cyan), and Black.
Equipped with ink nozzles that can eject each color of Y, M,
When expressing each single color of C and Black, recording is performed by ejecting one dot per pixel according to the recording information,
In addition, when creating colors by subtractive color mixing such as R (red), G (green), and B (blue), dots of the required color are placed one by one for each pixel to create the color and record. .

On the other hand, when the selection switch 14 is switched and an OHP film is selected, the system is changed so that a larger number of dots are formed per pixel than is normally formed. For example, dots of the same color are ejected twice to the same pixel of a single color so as to overlap each other, thereby performing double striking. This is done, for example, by recording dots from the opposite direction during the backward movement so as to overlap the printed dots during the forward movement, and then advancing the recording paper one line.

A configuration for performing dot recording as described above will be explained below with reference to FIG.

CPU (central control unit) 30 that controls the recording system
An up/down counter 31 is connected to the up/down counter 31, which counts up in synchronization with the clock from the CPU 30, and a data address corresponding to the counted value is sent via the address decoder 32. External data 3
RAM (Random Access Memory) 33 connected to 4
The recorded data 35 at that address is read out in synchronization with the clock. In this case, the ejection position is confirmed by the signal from the carriage position detection section 36, and the driver 37 is driven to perform dot recording via the inkjet unit (IJU) 38 according to the data 35 described above.

On the other hand, when returning, the counter 31 is used as a down counter, the number of counters 31 is made small, data is taken out in synchronization with the clock, and printing is performed during returning. As a result, the same data can be entered twice. The same can be considered when multiple printing is performed. In this case, the data in the RAM 33 continues to be held until reciprocating printing is performed a predetermined number of times, and the paper is not fed by the paper feeding mechanism 41.

When a certain value N (the number of overprints) initially set in the CPU 30 is reached, the RAM 33 is refreshed, new data is taken in, the paper is fed by the paper feed mechanism 41, and the next printing is started.

In this way, the amount of ink ejected and injected into each pixel is increased, and the recording density per pixel is increased. In this case, the dot diameter is also larger than in the case of one dot, approaching that when the recording medium is paper (this indicates that the space between the dots becomes narrower and the background portion decreases).

With such simple operations, a clear image with high recording density can be obtained even on an OHP film, and a sufficiently good image can be obtained even when projected onto a screen using transmitted light.

In addition to the embodiments described above, keys arranged on the operation panel 15 may be used in combination without providing a special switch. For example, using a photo sensor to detect the presence or absence of a recording medium, it is possible to
(The photo sensor does not detect this because the paper film is nearly transparent.) By operating one of the operation keys, the recording can be changed to OHP film, or the position of the paper release lever 13 can be used to determine this. It's okay.

[Effect] As explained above, according to the present invention, by providing a switch for changing the recording system, it is possible to record on an OHP film without adding any special equipment.
By overlapping dots on pixels multiple times, it is possible to obtain a vivid image with improved recording quality and recording density.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram when recording on plain paper, Fig. 2 is an explanatory diagram when recording on OHP film, Fig. 3 is a perspective view showing the external appearance of the inkjet recording device, and Fig. 4 is an explanatory diagram when recording on OHP film. FIG. 2 is a block diagram showing a configuration for performing overlapping. l...Pixel area 2.3...Dot diameter 11...Power switch 13...Release lever 14...Selection switch 15...Operation panel 30...CPU 38...Inkjet unit

Claims (1)

[Claims] In an inkjet recording device that performs recording by ejecting ink droplets onto a recording medium according to recording information, a switch is provided to switch between recording on a transparent recording medium and other recording media, and by switching this switch, recording can be performed on each recording medium. An inkjet recording apparatus characterized in that the number of ink droplets forming one pixel is changed when printing.