JP2804573B2 - Liquid jet recording device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid jet recording apparatus, and more particularly, to a liquid jet recording apparatus that controls head driving conditions in accordance with recording characteristics of a recording material.

[Conventional technology]

2. Description of the Related Art In a recording apparatus such as a facsimile, a copier, a printer, etc. by an electrophotographic method or an ink jet method in which two or more types of recording materials having different paper qualities are handled, the recording characteristics of each recording material differ depending on the type thereof. There is a point that stable high image quality cannot be obtained unless each recording material is used. Many inventions have been made in view of such a point especially in the electrophotographic system. However, among the recording apparatuses described above, in the ink jet system using a liquid, not only the moisture absorption of the film and the paper is significantly different, but also
Since various characteristics such as the degree of strike-through and the glossiness of the surface are different, it was difficult to obtain a stable recorded image.
That is, in general, the bleeding ratio is small and the ink does not strike through when the film is glossy and coated. On the other hand, paper generally has a different bleeding rate from a film and easily strikes through, and the paper is likely to undulate due to excessive ejection of ink.

Therefore, as disclosed in Japanese Patent Application Laid-Open No. 56-146772, a method of detecting the bleeding rate of the recording material and controlling the sub-scanning of the head as disclosed in Japanese Patent Application No. 63-148228 is disclosed. In addition, a proposal has been made to detect the smoothness of the recording material so that the dot diameter on the recording material is always kept constant.

[Problems to be solved by the invention]

However, in the above-described conventional method, it cannot be said that sufficient consideration has been given to the recording characteristics of the recording material, and in particular, observation conditions for a recorded image, which will be described later, are not taken into account. I couldn't. Here, the observation condition of the recorded image means an environment or a state when the recording material on which the recorded image is formed is used.

That is, in the case of a recording material used for an OHP or the like, the recording material is used as a transparent positive image. In such a use state, the periphery of the image is kept darker than the normal image. On the other hand, the human eye adapts to the average brightness of the image (adaptation to the image), and the visual characteristics are softened. Therefore, a harder density reproduction is suitable for the image in this case. On the other hand, when the image is viewed by reflected light like ordinary recording paper, the surrounding environment is sufficiently bright, and the eyes adapt to the surrounding brightness (environment adaptation), so that soft reproduction may be suitable. Even if the state of the recording material is detected, detecting only one characteristic such as smoothness or transparency, such as an OHP recording material, becomes transparent when heated and fixed even if it is opaque at the time of recording (heat transparent). Simply reflect the back print film (hereinafter BPF) used for recording methods that record a normal image on an OHP or recording material and observe it as a normal image by observing from the opposite side of the recording surface Since there are various things such as observation with light and observation with transmitted light from the recording surface, the detection means is insufficient. Even if the smoothness and the transparency are detected together, the heated transparent OHP sheet and the BPF are similar in both the smoothness and the transparency.

As described above, with the diversification of recording materials, various problems have not been solved by the recording detection and the recording method according to the related art.

An object of the present invention is to solve the above-mentioned conventional problems and to propose a liquid jet recording apparatus capable of always obtaining a stable recorded image corresponding to various types of recording materials.

[Means for solving the problem]

In order to achieve this object, the present invention is directed to recording a plurality of types of recording materials having different recording characteristics including ease of liquid bleeding, and discharging a liquid from a recording head to the recording material. What is claimed is: 1. A liquid jet recording apparatus for performing recording, comprising: driving condition setting means for setting a driving condition of the recording head according to a type of the recording material; and a periphery when observing the recording material on which a recording image is formed. Correction means for correcting the setting of the driving condition performed by the driving condition setting means according to the brightness condition.

[Action]

According to the present invention, the correction unit corrects the setting of the driving condition performed by the driving condition setting unit in accordance with the surrounding brightness condition when observing the recording material on which the recording image is formed. The reproduction is a reproduction suitable for the image adaptation of the observer's vision or the environment, and therefore, a higher quality image is formed.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail and specifically with reference to the drawings.

FIG. 1 shows an embodiment of the present invention. In the conventional recording procedure, when a recording signal is input, it is only output to the recording head via the output signal conversion means. However, the feature of this embodiment is that the recording condition setting means 1 instead of the output signal conversion means has Information about the recording material is input to the place via the detection means 2. The recording condition is determined by the setting means 1 by a signal based on the information, and then converted as an output signal. Output. Here, the recording material information refers to information on characteristics relating to the quality of the recording material, such as bleeding rate, strikethrough, surface glossiness, liquid hygroscopicity (amount and speed). The recording conditions described above are head driving conditions, that is, the amount of energy of an electric signal supplied as a driving voltage or a pulse waveform to the recording head,
Alternatively, the scanning density of the recording head relative to the recording material,
It refers to the head temperature and the like at the time of driving the head. Therefore, it is possible to widen the recording conditions by variously combining these conditions. For example, in the recording condition setting means 1, a table for setting recording conditions corresponding to the various characteristics described above is provided. The recording condition is set based on the information input from the detecting means 2, and the input signal is corrected and converted according to the condition.

FIG. 2 shows a modification in which, in addition to the above-described example, a correction means 5 for correcting the recording material under observation conditions is provided, and a correction signal is input to the recording condition setting means 1.
The correction in consideration of this observation condition will be described in each embodiment.

The present invention can be applied not only to the bubble jet system but also to various types of liquid jet recording apparatuses such as a piezo system. In the embodiments described below, there is provided a full-line type recording head having a multi-nozzle recording head. An apparatus as shown in FIG. 3 was used.

In FIG. 3, reference numeral 101 denotes 400 DP for ink jet recording.
Recording head formed on I
By inputting this pulse signal, thermal energy is given to the ink via a heater (not shown), and the ink is ejected in the form of flying droplets, thereby performing recording on the recording sheet 102. The recording head 101 is electrostatically attracted onto the transport belt 103 and is held at a distance of about 0.5 mm from the recording 102 transported in the direction A. When the recording sheet 102 is guided to a position facing the recording head 101, ink is ejected in accordance with a recording pulse signal, and recording is performed. FIG. 4 schematically shows the recording dot distribution when recording is performed in the normal mode on the most recommended recording sheet by this apparatus. In this case, the transport speed was 100 mm / sec, the head drive frequency was 1.6 kHz, and the sheet used had a bleed rate of 2.6 with coated paper. Furthermore, if the head temperature control temperature is about 40 ° C,
Although a dot diameter of 90 μm is obtained, the dot diameter becomes approximately 78 μm when printed on an OHP sheet under the same conditions.

FIG. 5 shows this in the same way as FIG. 4, and in these figures, a indicates the nozzle interval and the sub-scanning interval. That is, in FIG. 5, since the area occupancy of the dots (area factor or AF below) is clearly small, the density (hereinafter OD) becomes low. Therefore, in the case of FIG. 5, if the sub-scanning density is controlled so that the ejection amount is equivalent to about 1.2 times in order to keep the dot diameter constant, the OD hardly changes because the AF is constant. As described above, in the OHP sheet which becomes image-adapted when the observation conditions are taken into consideration, it is preferable to reproduce a hard color density. Therefore, it is better to set the ejection amount to be somewhat larger than 1.2. Therefore, as shown in FIG. 6, it is harder to double the sub-scanning density, that is, to halve the paper feed speed to 800 dpi, or to increase the paper feed speed to 75 mm / sec and increase it slightly to 600 dpi. It becomes density reproduction, and it is also preferred for appearance. However, in order to increase the driving amount, it is needless to say that in the case of an OHP sheet, consideration must be given to a large problem of fixability.

FIG. 7 shows a correlation between the actually measured driving amount by the recording head 101 and the OD. As is clear from this figure, the driving amount is 10
At nl / mm ² or less, the OD is considerably low at 0.7 to 0.8, indicating that the concentration is insufficient. FIG. 8 shows the relationship between the driving amount and the fixing time. In this case, the fixing time is 80 ° C with hot air.
For 15 seconds and further dried by blowing cold air at 22 ° C. (room temperature) for 30 seconds.
Here, it is characteristic that the fixing time has a critical value depending on various conditions, and the fixing time tends to rapidly increase after the critical value. Therefore, the scanning density (paper feed speed) in the sub-scanning direction should be determined based on the above-described critical value of the fixing time, the OD, and the normal scanning density. In this embodiment, when the normal ejection amount is 7 nl / mm ² (400 dpi), the transport speed is 75% in the OHP mode, that is, when the sub-scanning direction is set to a driving amount of about 11 nl / mm ² corresponding to 600 dpi, the value is 8.4. nl / mm ² (= 7 ×
1.2) and simply converted to the dot diameter from the bleed rate, the value was larger than when the AF was the same as that of the coated paper, and a higher quality image was obtained than when the AF was the same as in the conventional example.

(Example 2) As a method of correcting AF due to a difference in the bleed rate, a sixth method is described.
In addition to the density modulation in the sub-scanning direction shown in the figure, the dot diameter can be controlled. It is known to modulate the pulse width of a recording signal as one method of controlling the dot diameter. If the pulse width is increased, the dot diameter can be increased as shown in FIG. Therefore, a long pulse width is given to a sheet having a small bleeding rate like an OHP sheet, and a small pulse width is given to a recording sheet having a large bleeding rate. In this case, it is possible to eliminate the difficulty in increasing the OD.

Third Embodiment In the second embodiment, as shown in FIG. 9, when the dot diameter is increased to a certain dot diameter, the dot diameter becomes substantially constant even if the pulse width is further increased. Further, the pulse width is not infinitely widened but relates to the life of various components. When a bubble jet recording head is used as in this embodiment, the life of the heater is related to the cavitation of bubbles, and the ratio of the critical discharge voltage (Vth) at an arbitrary nozzle to the actual head drive voltage (Vop) is determined. It is known that the service life is shortened as the value of k is determined by (k value), and the higher the value of k is, the more rapidly it deteriorates when this value is higher than 1.20.

Therefore, there is a limit in controlling the dot diameter only by the pulse width modulation. Therefore, in this embodiment, as a countermeasure, a subheat pulse in which the number of pulses is divided into two or more rather than one is used. That is, by using this method, which is known as one of the methods for correcting the density unevenness of the recording by controlling the dot diameter, it is possible to change the dot diameter according to the characteristics of the recording material while correcting the unevenness. FIG. 10 shows changes in dot diameter and OD when the sub-heat pulse and the pulse width modulation are used in combination. As can be seen from this figure, it is possible to realize a large dot diameter and OD that cannot be achieved by pulse width modulation alone without forcibly increasing the k value. Therefore, this characteristic is utilized for the correction of unevenness for each bit, and according to the characteristic of the recording material, for example, in the case of an OHP sheet or the like, a large dot diameter can be obtained on average for all nozzles according to the second embodiment. By setting, an image corresponding to the use of the recording material can be obtained while suppressing unevenness.

(Embodiment 4) As shown in FIG. 10 and FIG. 11 which is a graph of FIG. 10, in the control by the sub-heat pulse, in terms of the correction of the dot diameter, at most 70 to 80% of the maximum value is controlled. You can't do it. However, in this case, when correcting the entire dot diameter depending on the recording material, for example, OH
In the case of a P sheet or the like having a very small dot diameter or a recording sheet having a large bleeding ratio and having a nozzle having a large dot diameter, the control range may become uneven. Therefore, regarding AF, according to the recording material (Example 1)
As described above, if control is performed by means other than the dot diameter control and only the dot diameter is controlled with respect to the unevenness correction, the control range is not restricted.

(Embodiment 5) In this embodiment, the dot diameter is controlled by the head drive voltage instead of the pulse width and the sub-heat pulse control. Eleventh
The figure shows the change in dot diameter depending on the head drive voltage (Vop). Also in the case of this example, like the pulse width modulation shown in (Example 2), it can be seen that the dot diameter hardly changes when the voltage exceeds a certain value. Of course, since there is a relationship with the k value, the dot diameter voltage modulation is performed within the above-mentioned limit. In the case of the present embodiment, the control range becomes too narrow to perform both the unevenness correction and the reproduction of the density according to the characteristics of the recording material only by the voltage correction. Therefore, the parallel use with other embodiments is preferable.

(Example 6) In the case of an ink jet printer, the liquid viscosity greatly affects the recording characteristics. In particular, in a printer using a head that utilizes the heat of a heater as the energy for ejecting ink, unlike the charge control type, the influence of the viscosity is remarkable, and many head temperature control means and methods have been conventionally proposed. .

In this embodiment, the head temperature is adjusted and controlled in accordance with the characteristics of the recording material. FIG. 12 shows the dot diameter and OD when recording is performed on coated paper and plain paper while changing the head temperature.
Is shown. As described above, it is known that the dot diameter increases as the temperature rises because the viscosity of the ink decreases and the ejection becomes easier. The rate of change also differs depending on the type of the recording material. In general, in the case of a multi-head, the temperature of the head cannot be raised so much because an IC or a vapor-deposited film is generally used, so it is necessary to set the temperature control temperature according to the characteristics of the recording material in consideration of these circumstances. Of course there is.

Also, in the case of coated paper, if the amount of ink applied is increased, an allowable amount of thickness is necessary, and in general, the thickness is required in accordance with the allowable amount and the cost is also increased. However, since the bleeding rate of plain paper is small, even if the same ink is used, it is necessary to increase the ejection amount, increase the dot diameter, and improve the OD even if the same ink is used. Furthermore, in the case of an OHP sheet, although the bleeding rate is the same as that of plain paper, it is used as a transparent positive image. That is, it is necessary to increase the driving amount in the order of the coated paper, the plain paper, and the OHP sheet. Therefore, the temperature control temperature may be increased accordingly.

〔The invention's effect〕

As described above, according to the present invention, the setting of the driving condition performed by the driving condition setting unit in accordance with the condition of the surrounding brightness when the correcting unit observes the recording material on which the recorded image is formed is set. Since the correction is performed, the density reproduction in the recorded image becomes a reproduction suitable for the visual image adaptation of the observer or the environmental adaptation, and therefore, a higher quality image can be formed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a block diagram showing still another embodiment of the present invention, and FIG. 3 is a perspective view showing an example of a bubble jet recording apparatus according to the present invention. Fig. 4 is a diagram schematically showing dots during normal recording, Fig. 5 is a dot distribution diagram when recording is performed on a recording material having a low bleeding rate by normal paper feeding, and Fig. 6 is a diagram in Fig. 4. FIG. 7 is a graph showing the relationship between the ink ejection amount and OD _max when the recording is performed on the recording material at a normal 50% speed paper feed. FIG. 8 is a diagram showing the relationship between the ink ejection amount and OD _max . FIG. 9 is a diagram showing the relationship between the fixing time and the pulse width, FIG. 9 is a diagram showing the relationship between the pulse width and the dot diameter, FIG. FIG. 11 is a diagram showing FIG. 10 as a graph, FIG. 12 is a diagram showing a change in dot diameter depending on the drive voltage, and FIG. DOO paper is a diagram showing the temperature change of the dot diameter on plain paper. a: nozzle interval, 101: recording head, 102: recording sheet, 103: transport belt.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Haruhiko Moriguchi 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References JP-A-56-1476769 (JP, A) JP-A-56 JP-A-146770 (JP, A) JP-A-62-113564 (JP, A) JP-A-61-104874 (JP, A) JP-A-1-290440 (JP, A) JP-A-63-312155 (JP, A) (58) Field surveyed (Int.Cl. ⁶ , DB name) B41J 2/05

Claims (2)

(57) [Claims] 1. A liquid jet recording apparatus for recording a plurality of types of recording materials having different recording characteristics including ease of liquid bleeding and ejecting a liquid from a recording head to the recording material to perform recording. A driving condition setting means for setting a driving condition of the recording head according to a type of the recording material; and a driving condition setting unit for setting a driving condition of the recording head according to a surrounding brightness condition when observing the recording material on which a recording image is formed. And a correction means for correcting the setting of the driving condition performed by the driving condition setting means. 2. The liquid jet recording apparatus according to claim 1, wherein the recording head has a thermal energy generator for generating thermal energy for discharging the liquid.