JP2831424B2 - Ink jet recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a recording apparatus having a plurality of recording heads provided with thermal energy generating means for discharging a recording liquid. The present invention relates to an ink jet recording apparatus provided with a unit for correcting uniformity.

[Conventional technology]

2. Description of the Related Art Conventionally, an inkjet recording apparatus that performs recording by discharging ink onto a recording material has been known.

Ink jet recording apparatuses are non-impact type recording apparatuses, and have features such as low noise and easy color image recording by using multi-color inks. It is getting. But,
Ink jet recording devices perform recording by directly ejecting ink from the fine nozzles of the recording head, and special considerations that are not seen in other types of recording devices are required to always maintain stable ejection. Is done.

In particular, bubble jet recording devices that use thermal energy as an energy source for ejecting a recording liquid have rapidly spread due to the ease of multi-formatting. Was needed.

[Problems to be solved by the invention]

However, in the above-described conventional example, in the case of a recording apparatus having a plurality of recording heads, for example, four recording heads of cyan C, magenta M, yellow Y, and black BK for full-color recording, the cooling fan blows air. For example, two recording heads located inside are
Since it is surrounded by the recording heads (thermal heads) on both outer sides, the temperature control that is normally performed cannot be strictly performed, and the recording head temperature rises. Therefore, there is a problem that the temperature rise of each recording head becomes non-uniform.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the related art, and provides an ink jet recording apparatus capable of performing stable ejection by eliminating non-uniformity in temperature rise of a plurality of recording heads. It is intended to be.

[Means for Solving the Problems] In order to achieve the above object, an ink jet recording apparatus of the present invention is directed to an ink jet recording apparatus that performs recording by discharging a recording liquid onto a recording medium. A recording head array comprising a plurality of recording heads arranged side by side, comprising: a means for generating energy; a temperature detecting means provided in each of the recording heads; and a heater for heating the recording heads. A heating unit, a cooling unit for cooling the recording head, a control unit for controlling the heating unit and the cooling unit based on a detection result by the temperature detection unit, and a position where each of the recording heads is disposed. Correction means for correcting the non-uniformity of the temperature of each print head during printing due to printing, wherein the print head row is located on both outer sides of the print head row. And a recording head located inside the recording heads located on both outer sides. The correction unit is configured to make the recording located on the both outer sides in order to equalize the temperature of each recording head during recording. It is characterized in that a correction is made to increase the heat radiation of the heat generated from the recording head located inside than the heat radiation of the heat generated from the head.

The means for correcting the non-uniformity of the temperature rise of each print head during printing may be a temperature setting means for determining a set temperature for each print head according to the print head position, or a temperature detection for the print head located inside. The position of the means is made lower than the position of the recording head located on both outer sides with respect to the heat source, or the heat radiation capability of each recording head is made different according to the non-uniformity of the temperature rise of each recording head during recording. It is good to use a heat radiation means.

Further, the thermal energy generating means for discharging the recording liquid may be an electrothermal converter.

[Action]

The ink jet recording apparatus of the present invention configured as described above detects a temperature rise for each recording head by temperature detecting means provided on each recording head, and based on the detected value, the temperature of each recording head during recording is determined. By controlling the temperature rise of each print head by operating the means for correcting the non-uniformity of the rise, it is possible to always keep the temperature rise of each print head uniform and constant.

〔Example〕

 An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows an example of an ink jet recording apparatus to which the present invention is applied. Here, a case of a multicolor recording apparatus using the recording head of the first embodiment of the present invention shown in FIG. 2 will be described as an example.

As shown in FIG. 2, the recording head unit 1 includes a plurality of recording heads 1A to 1D.
Recording liquids of different colors are ejected from 1D. Also, each of the recording heads 1A to 1D has a plurality of ejection ports provided in a row.
An electrothermal converter 40 is provided for each liquid path to which an applied voltage is supplied to generate thermal energy in order to discharge the recording liquid from 30.
Are arranged. Then, by applying a drive signal, heat energy is generated in the electrothermal transducer 40 to cause film boiling and form bubbles in the ink liquid path. Drops are ejected (see FIG. 6). A carriage 3 on which the recording head unit 1 is mounted and which moves along a guide rail 4;
5 is a timing belt for moving the carriage 3, and 6 is a carriage drive motor. Further, the recording sheet 7 is held at a recording position by a sheet feed roller pair 9 driven by a sheet feed motor 8 and a holding roller pair 10 cooperating with the sheet feed roller pair 9, and each time one-line sentence recording is completed. The sheet is fed in the direction of the arrow. 11 is a supply pipe for supplying ink to the recording heads 1A to 1D, 12 is a return pipe for returning ink from the recording heads 1A to 1D to the tank 13, and 14 is a recording head unit when the carriage 4 is brought to the home position H. 1, a non-discharge recovery device for a plurality of print heads for performing non-discharge recovery, and a cooling fan 2 for cooling the print head unit 1; And on the opposite side.

FIG. 2 is a perspective view of the recording head unit 1. As shown in FIG. 2, the recording heads 1A to 1D have temperature detecting means 20A to 20D disposed on the side and substantially forward thereof. Thermistor, temperature as the temperature detecting means 20A to 20D
Known means such as an IC and a thermocouple can be applied. Further 21A-2
Reference numeral 1D denotes a side surface of each of the recording heads 1A to 1D, which is a heating element as a heating means disposed substantially below the center portion. As the heating elements 21A to 21B, a heater, a power transistor, or the like is used.

 Next, the operation of the present embodiment will be described.

FIG. 3 is a conceptual diagram of the temperature control of the recording head temperature of the injection recording apparatus of the present invention.

In the case of the conventional example, the cooling fan and the heating means are operated so that each recording head has the same set temperature.

On the other hand, in the embodiment of the present invention, as shown in FIG. 3, the recording heads 1B and 1C of magenta M and yellow Y, for example, located inside the recording unit 1, are recording heads on both outer sides thereof. Certain cyan C and black BK are affected by heat from the recording heads 1A and 1D. Regarding heat dissipation, the recording heads 1A and
Since the condition is worse than 1D, each temperature detection means 20A ~ 20D
The temperature of each of the recording heads is detected, and the set temperatures of the magenta M and yellow Y recording heads 1B and 1C are compared with the set temperatures of the cyan C and black BK recording heads 1A and 1D (40 ° C. in the illustrated example). Is set to a slightly lower set temperature (38 ° C. in the illustrated example). Thereby, the magenta M,
The temperature of each of the recording heads for yellow Y can always be kept constant (39 ° C. to 40 ° C. in the illustrated example).

Note that each recording head used in the above illustrated example is 400 dpi, 1
This is a 28-jet bubble jet recording head with a head spacing of 10 mm and a heating value of 20 W.

As is apparent from the above description, in this embodiment, the means for correcting the non-uniformity of the temperature rise of each print head is constituted by the temperature setting means for determining the set temperature for each print head according to the print head position. ing.

FIG. 4 shows the configuration of each recording head according to the second embodiment of the present invention. (A) is a cross-sectional view of the recording head 41A for magenta M and yellow Y, and (B) is cyan C and black B.
FIG. 9 is a sectional view of a K recording head 41B. As shown in FIG. 4 (A), in the magenta M and yellow Y recording heads 41A which are the inner recording heads, the position of the temperature detecting means is the thermal energy generating means of the nozzle portion (hereinafter referred to as "heat source"). Hole in the board 41A-1 so that the hole 41A-
4 and a silicon layer 41A indicated by a cross in the hole 41A-4.
-2 in the vicinity of the temperature detecting means.

On the other hand, as shown in FIG. 4 (B), the recording heads 41B of cyan C and black BK, which are recording heads located on both outer sides, are arranged so that the position of the temperature detecting means is located far from the heat source. It is arranged on the surface of the substrate 41B-1 indicated by the mark on the side opposite to the nozzle.

Except that the recording head is constituted by the recording heads 41A and 41B as described above, the configuration is the same as that of the first embodiment described above, and the description is omitted.

In the present embodiment, the temperature detection means is disposed at a position far from the heat source in the cyan C and black BK recording heads 41B on both outer sides. Therefore, the temperature detecting means detects a temperature lower than the set temperature. On the other hand, the inner magenta M and yellow Y recording heads are provided with temperature detecting means at a position close to the heat source.
The temperature detecting means detects a temperature higher than the detected temperatures of the cyan C and black BK recording heads. As a result, when the temperatures of the recording heads are controlled based on these detected temperatures, the temperatures of the cyan and black BK recording heads on both sides are relatively high, and
The temperatures of the inner magenta M and yellow Y print heads are kept slightly lower than the temperatures of the cyan C and black BK print heads, and each print head can be maintained at a temperature substantially equal to the set temperature. it can. Therefore, for the same reason as described in the description of the first embodiment, the temperature rise of each recording head is always maintained at a uniform temperature.

FIG. 5 is a perspective view showing a recording head according to a third embodiment of the present invention. The same parts as those in the first embodiment shown in FIG. Only different parts will be described below.

As shown in FIG. 5, heat radiation fins 31 and 32 are provided on the inner recording heads 1B and 1C, respectively, so that the heat radiation capacity of the recording heads 1B and 1C is increased. In this case, the temperature rise is suppressed rather than the temperature rise of the recording heads 1A to 1D, thereby eliminating the non-uniformity of the temperature rise of each of the recording heads 1A to 1D.

Further, other heat radiation means in place of the heat radiation fin of the present embodiment,
For example, a Peltier element or the like may be provided. Further, a radiation fin may be provided for each recording head, and the surface area thereof may be increased so that the radiation effect of the inner recording head is increased, so that the radiation capability of the radiation means is made different. Good.

The present invention brings about an excellent effect particularly in a recording head and a recording apparatus of a bubble jet system among the ink jet recording systems.

Regarding the representative configuration and principle, it is preferable to use the basic principle disclosed in, for example, US Pat. Nos. 4,723,129 and 47,470,796.
This method can be applied to both the so-called on-demand type and the continuous type. In particular, in the case of the on-demand type, it is arranged corresponding to the sheet or liquid path holding the liquid (ink). By applying at least one drive signal corresponding to the recording information and giving a rapid temperature rise exceeding nucleate boiling to the electrothermal transducer, heat energy is generated in the electrothermal transducer, and the recording head This is effective because it is possible to form a film in the liquid (ink) by one-to-one correspondence with the drive signal as a result of film boiling on the heat-acting surface. The liquid (ink) is ejected through the ejection opening by the growth and contraction of the bubble to form at least one droplet. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,434,262 are suitable. Further, when the conditions described in US Pat. No. 4,313,124 of the invention relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

As a configuration of the recording head, in addition to a combination configuration (a linear liquid flow path or a right-angle liquid flow path) of a discharge port, a liquid path, and an electrothermal converter as disclosed in each of the above-described specifications, a heat acting section May be configured using those described in U.S. Pat. No. 4,558,333 and U.S. Pat. In addition, for a plurality of electrothermal transducers, JP-A-59-123670 discloses a configuration in which a common slit is used as a discharge portion of the electrothermal transducer, and an aperture for absorbing pressure waves of thermal energy. The effect of the present invention is effective even if the configuration is based on Japanese Patent Application Laid-Open No. 138461/1984, which discloses a configuration corresponding to the discharge unit.

In addition, a replaceable chip-type recording head that can be electrically connected to the apparatus main body and supplied with ink from the apparatus main body by being attached to the apparatus main body, or provided integrally with the recording head itself The present invention is also effective when a cartridge type recording head is used.

Further, it is preferable to add recovery means for the print head, preliminary auxiliary means, and the like, which are provided as components of the printing apparatus of the present invention, since the effects of the present invention can be further stabilized. If these are specifically mentioned, capping means for the recording head, cleaning means, pressurizing or suction means, preheating means using an electrothermal converter or another heating element or a combination thereof, and printing Performing a preliminary ejection mode for performing another ejection is also effective for performing stable printing.

Further, the present invention is extremely effective for an apparatus provided with at least one of a multicolor of different colors or a full color by mixing colors.

〔The invention's effect〕

Since the present invention is configured as described above, it has the following effects.

In an ink jet recording apparatus having a plurality of recording heads provided with thermal energy generating means for discharging a recording liquid, non-uniformity in temperature rise due to the position of each head is eliminated, and the temperature rise between each head is always kept at a uniform temperature. Keep,
Stable ejection of the recording liquid can be performed.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of an example of an ink jet recording apparatus to which the present invention is applied, FIG. 2 is a perspective view of each recording head of the first embodiment, and FIG. 4A and 4B are schematic cross-sectional views of the recording head of the second embodiment, FIG. 5 is a perspective view of each recording head of the third embodiment, and FIG. FIG. 1 is a perspective view showing a part of a recording head according to the present invention in a cutaway manner. DESCRIPTION OF SYMBOLS 1 ... Recording unit, 1A, 1B, 1C, 1D, 41A, 41B ... Recording head, 2 ... Cooling fan, 3 ... Carriage, 20A, 20B, 20C, 20D ... Temperature detection means, 21A, 21B, 21C, 21D: heating element 30: discharge port, 31, 32: radiation fin, 40: electrothermal converter, 41A-1, 41B-1: substrate, 41A-3, 41B-3: nozzle Hole, 41A-4 ... hole.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B41J 2 / 01,2 / 05,2 / 12

Claims (5)

(57) [Claims] 1. An ink jet recording apparatus for discharging a recording liquid onto a recording medium for recording, comprising: means for generating thermal energy for discharging the recording liquid, comprising a plurality of recording heads arranged side by side. A recording head array; a temperature detecting unit provided for each of the recording heads; a heating unit for heating the recording head; a cooling unit for cooling the recording head; and a detection by the temperature detecting unit. Control means for controlling the heating means and the cooling means based on the result; andcorrection means for correcting the non-uniformity of the temperature of each recording head during recording due to the position where each of the recording heads is disposed. The recording head row includes a recording head located on both outer sides of the recording head row, and a recording head located inside a recording head located on the both outer sides, The correction unit is configured to increase the heat radiation of the heat generated from the print heads located on the inner side compared with the heat radiation generated by the print heads positioned on the inner side in order to equalize the temperature of each print head during printing. An ink jet recording apparatus, comprising: 2. The apparatus according to claim 1, wherein said correction means includes a temperature setting means for setting a set temperature for the print heads located on the inner side by a predetermined temperature lower than a set temperature for the print heads located on both outer sides. The ink jet recording apparatus according to claim 1, wherein 3. The printing apparatus according to claim 2, wherein the position of the temperature detecting means of the recording head located on the inner side is closer to the heat source than the positions of the temperature detecting means of the recording heads located on both outer sides. The injection recording apparatus according to claim 1, wherein 4. The correcting means includes a heat radiating means for making the heat radiating ability of the heat generated from the recording head located on the inner side larger than the heat radiating capacity of the heat generated from the recording heads located on the both outer sides. The ink jet recording apparatus according to claim 1, wherein 5. The ink jet recording apparatus according to claim 1, wherein the thermal energy generating means of the recording head is an electrothermal converter.