WO2006054533A1

WO2006054533A1 - Inkjet recording device

Info

Publication number: WO2006054533A1
Application number: PCT/JP2005/020908
Authority: WO
Inventors: Takeshi Yokoyama
Original assignee: Konica Minolta Medical & Graphic, Inc.
Priority date: 2004-11-22
Filing date: 2005-11-15
Publication date: 2006-05-26
Also published as: JP2006142706A

Abstract

An inkjet recording device is characterized in that the device is provided with a recording head for jetting an ultraviolet curing ink on a recording medium; ultraviolet irradiation equipment having a low-pressure mercury vapor lamp as a light source for irradiating the jetted ink with ultraviolet rays; a temperature sensor for detecting the temperature of a cap part of the light source; a cooling device for controlling the cap temperature; an illuminance sensor for detecting illuminance of the ultraviolet irradiation equipment; and a control section for controlling the cap temperature to have illuminance of the ultraviolet rays from the ultraviolet irradiation equipment to be substantially uniform, based on the detection results from the temperature sensor and the illuminance sensor.

Description

Specification

Inkjet recording device

Technical field

TECHNICAL FIELD [0001] The present invention relates to an inkjet recording apparatus, and more particularly to an inkjet recording apparatus that records an image using a photocurable ink that is cured by irradiation with light.

Background art

[0002] In recent years, inkjet recording apparatuses are often used because images can be formed easily and inexpensively compared to methods that require plate making, such as gravure printing methods and flexographic printing methods. It is becoming.

[0003] In the field of image recording on products and product packaging using an ink jet recording apparatus, materials that are not ink-absorbing, such as resin, are often used for products and product packaging. In order to fix the ink to the recording medium using such a material having no ink absorbability as a recording medium, a nozzle for discharging ink that is cured by irradiating light such as ultraviolet rays is provided. A recording head and an ultraviolet irradiation device provided with a light source that generates ultraviolet rays for curing the ink. After the ink ejected from the nozzle cover is landed on the recording medium, the ultraviolet irradiation device is applied to the recording medium. 2. Related Art Inkjet recording apparatuses that form an image by curing ink by irradiating ultraviolet rays are known (for example, see Patent Documents 1 and 2).

[0004] Here, if the time until the ink lands on the recording medium and the ultraviolet light is irradiated is long, the dot diameter of the ink that has landed on the recording medium increases, causing blurring or color mixing. The image quality is degraded. Therefore, in order to shorten the time from the ink landing on the recording medium to the irradiation of ultraviolet rays, the conventional inkjet recording apparatus is provided with the ultraviolet irradiation apparatus close to the recording head. For this reason, the ultraviolet irradiation device covers the light source in order to prevent the ultraviolet light emitted from the light source from reaching the nozzle formation surface of the recording head and curing the ink adhering to the nozzle formation surface. A cover member is provided.

[0005] By the way, in recent years, an energy storage type cation curable ink that can be cured by irradiating with low-illuminance ultraviolet rays for a long time has been proposed. In order to cure, a low-power, low-output ultraviolet light source such as a low-pressure mercury lamp or a cold cathode tube can be used.

[0006] When using this low output type light source, in order to obtain a predetermined light amount necessary for curing the ink, an ultraviolet irradiation device in which a plurality of light sources are arranged in the relative movement direction with respect to the recording medium, By arranging a plurality of ultraviolet irradiation devices in the direction of relative movement with the recording medium, it has been proposed to obtain a predetermined amount of light by irradiating the ink landed on the recording medium a plurality of times even at low illuminance. .

Patent Document 1: Japanese Patent Laid-Open No. 2001-310454

Patent Document 2: Japanese Patent Laid-Open No. 2003-145725

Disclosure of the invention

Problems to be solved by the invention

[0007] In an inkjet recording apparatus including a plurality of ultraviolet irradiation devices and a plurality of low output type light sources that also have low output type light source power, there is a variation in the amount of light from each ultraviolet irradiation device or each light source. In addition, since the time required for curing each dot differs depending on the location, there is a problem that the dot diameter may be different in one printed matter and the image quality may be deteriorated.

[0008] The present invention has been made in view of such circumstances, and an inkjet capable of performing high-quality image recording by making the light amounts of a plurality of ultraviolet irradiation devices and a plurality of low-output ultraviolet light sources uniform. An object of the present invention is to provide a recording apparatus.

Means for solving the problem

In order to solve the above problems, the present invention includes configurations of the following items.

Term 1

A recording head for discharging ultraviolet curable ink onto a recording medium;

A plurality of ultraviolet irradiation devices including, as a light source, a low-pressure mercury lamp that irradiates the discharged ink with ultraviolet rays;

Temperature detecting means for detecting the temperature of the base portion of the light source;

A base temperature control means for controlling the temperature of the base part;

Illuminance detection means for detecting the illuminance of the ultraviolet irradiation device; And a control unit that controls the temperature of the base part so that the illuminance of ultraviolet rays from the plurality of ultraviolet ray irradiation devices is substantially uniform based on the detection results of the temperature detection unit and the illuminance detection unit. An ink jet recording apparatus.

[0010] According to the configuration described in Item 1, the control unit sets the light source of each light source so that the illuminance of the ultraviolet rays of the plurality of ultraviolet irradiation devices is substantially uniform based on the detection results of the temperature detection means and the illuminance detection means. Since the die temperature can be controlled, it is possible to make the illuminance of ultraviolet rays from each ultraviolet irradiation device substantially uniform.

Term 2

An ultraviolet irradiation device comprising a plurality of low-pressure mercury lamps that irradiate the discharged ink with ultraviolet rays as light sources;

Illuminance detection means for detecting the illuminance of the light source;

Based on the detected illuminance of the temperature detecting means and the illuminance detecting means, an illuminance distribution of ultraviolet rays from the light source with respect to the temperature of the base part is generated, and based on the generated illuminance distribution, the ultraviolet light from a plurality of the light sources is generated. An ink jet recording apparatus comprising: a control unit configured to control a temperature of the base unit so that illuminance is substantially uniform.

[0011] According to the configuration described in Item 2, the base temperature of the light source is controlled so that the illuminance of the ultraviolet light from each light source is substantially uniform based on the illuminance distribution of the ultraviolet light from each light source with respect to the base temperature. Therefore, it is possible to make the illuminance of ultraviolet rays having almost the same light source power substantially uniform. Item 3

In the ink jet recording apparatus according to Item 1 or 2,

The ink jet recording apparatus according to claim 1, wherein the ink is a cation polymerization type ink including a cation polymerizable compound as a main component.

[0012] According to the configuration described in Item 3, since the illuminance of ultraviolet rays is adjusted to be substantially uniform even when the ink is a cationic polymerization type ink, the ink is applied to the ink that has landed on the recording medium. Irrespective of the bullet position, ultraviolet rays can be irradiated substantially uniformly. The invention's effect

[0013] According to the configuration described in item 1, since the illuminance of ultraviolet rays from each ultraviolet irradiation device can be made substantially uniform, the time required for the ink that has landed on the recording medium to be cured is independent of the landing position. Since they are substantially equal, the ink can be cured uniformly and a good image can be obtained.

[0014] According to the configuration described in item 2, since the illuminance of ultraviolet rays of each light source power can be made substantially uniform, the time required for the ink that has landed on the recording medium to be cured is short regardless of the landing position. As a result, the ink can be cured uniformly and a good image can be obtained.

[0015] According to the configuration described in Item 3, even if the ink is a cationic polymerization type ink, since the illuminance of ultraviolet rays is adjusted to be substantially uniform, the ink landing on the recording medium is adjusted. Irrespective of the bullet position, ultraviolet rays can be irradiated substantially uniformly.

Brief Description of Drawings

FIG. 1 is a perspective view showing a configuration of a main part of an embodiment of an ink jet recording apparatus according to the present invention.

FIG. 2 is a perspective view showing a carriage and an ultraviolet irradiation device in the first embodiment.

FIG. 3 is a bottom view of the ultraviolet irradiation device according to the first embodiment.

FIG. 4 is a diagram showing the relationship between the temperature of the base of a low-pressure mercury lamp and the illuminance of the irradiated ultraviolet light.

FIG. 5 is an enlarged perspective view showing a peripheral structure of the cooling device in the first embodiment.

FIG. 6 is a block diagram showing a circuit configuration in the first embodiment.

FIG. 7 is a perspective view of an ultraviolet irradiation device according to a second embodiment.

Explanation of symbols

[0017] 5 recording head

7A, 7B, 70 UV irradiation equipment

9A, 9B, 90 Low pressure mercury lamp

11, 110 arc tube

12 Base part 13 Temperature sensor

14 Cooling device

21 Illuminance sensor

23 Control unit

BEST MODE FOR CARRYING OUT THE INVENTION

[0018] Hereinafter, embodiments of the ink jet printer of the present invention will be described with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples.

(First embodiment)

FIG. 1 shows an ink jet recording apparatus according to this embodiment. The ink jet recording apparatus according to this embodiment is a serial head type ink jet recording apparatus, and includes a recording apparatus main body 1 and a support base 2 that supports the recording apparatus main body 1.

[0019] Inside the recording apparatus main body 1, a rod-shaped guide rail 3 is provided, and a carriage 4 is supported on the guide rail 3. The carriage 4 is reciprocated in the scanning direction, which is the width direction of the recording medium, along the guide rail 3 by a carriage driving device (not shown).

As shown in FIG. 2, the carriage 4 is equipped with a recording head 5 that ejects ink of a predetermined color. Each of the recording heads 5 has a substantially rectangular parallelepiped shape and is arranged so that the longitudinal directions thereof are parallel to each other. A plurality of nozzles (not shown) for ejecting ink onto the recording medium are provided on the surface of each recording head 5 facing the recording medium along the transport direction. The carriage 4 is provided with an intermediate tank 6 for storing ink and supplying ink to the recording head 5. The recording head 5 is communicated with the intermediate tank 6 through an ink supply pipe 51.

In addition, ultraviolet irradiation devices 7A and 7B are provided on both sides of the carriage 4 in the scanning direction of the recording head 5 to irradiate the ink discharged from the nozzles onto the recording medium and cure the ink. It has been. Each of the ultraviolet irradiation devices 7A and 7B is provided with a box-shaped light source cover 8 that opens toward the recording medium. Inside the light source cover 8, one low pressure mercury lamps 9A and 9B are provided as light sources for radiating ultraviolet rays radially. As shown in FIG. 3, the low-pressure mercury lamps 9A and 9B are composed of a rod-like arc tube 11 and cylindrical cap portions 12 attached to both ends thereof. The arc tube 11 is formed to have a length equal to or longer than the length of the recording head 5 in the longitudinal direction, and a plurality of bent portions 10 are provided at predetermined positions. In the low-pressure mercury lamps 9A and 9B having such a configuration, the arc tube 11 emits light when the base portion 12 is energized. Note that the shape of the arc tube 11 of the low-pressure mercury lamps 9A and 9B is not limited to that shown in the figure. For example, the arc tube is formed in a U shape by providing only one bent portion, and both ends of the arc tube are formed. Use a structure that has a base attached to the base.

[0023] Further, a temperature sensor 13 as a temperature detecting means is installed in the base part 12 of each low-pressure mercury lamp 9A, 9B, and the temperature of each base part 12 is detected.

Here, the illuminance of ultraviolet rays from the low-pressure mercury lamps 9A and 9B varies depending on the temperature of the base part 12, but the mode of the change may vary depending on the characteristics of the low-pressure mercury lamps 9A and 9B. For example, FIG. 4 is a diagram showing the relationship between the base temperature and the illuminance of the low-pressure mercury lamps 9A and 9B. As shown in this figure, the low-pressure mercury lamps 9A and 9B may have different illuminances of the irradiated ultraviolet rays even if the base temperature is the same. Therefore, in an inkjet recording apparatus including a plurality of ultraviolet irradiation devices 7A and 7B as in the present embodiment, in order to make the illuminance of ultraviolet rays uniform, the reference illuminance to be irradiated is determined and the ultraviolet rays having the reference illuminance are irradiated. The temperature of the base is adjusted. Specifically, when the reference illuminance is set to X, the base temperature of the low-pressure mercury lamp 9A provided in the ultraviolet irradiation device 7A is set to a ° C, and the base temperature of the low-pressure mercury lamp 9B provided in the ultraviolet irradiation device 7B. By adjusting the temperature to b ° C, the illuminance from the UV irradiation devices 7A and 7B becomes substantially uniform.

[0025] On the upper surface of the light source cover 8 (the surface opposite to the opening side), an air cooling type cooling device 14 is provided as a base temperature control means. The cooling device 14 includes an air cooling fan 15, a drive motor for the air cooling fan 15 (not shown), and a housing 16 for storing the air cooling fan 15. As shown in FIG. 5, a slit-like outside air intake port 17 is provided on one surface of the light source cover 8 so as to face the base portions 12 of the low-pressure mercury lamps 9A and 9B. Therefore, the outside air taken in from the outside air intake port 17 immediately hits each of the base parts 12, and the base part 12 can be cooled well. It is. On the other hand, the casing 16 is provided with an exhaust port 18 opened in a direction not facing the recording medium. Therefore, the exhaust port 18 has no influence on the image formation in which the exhaust of the internal force of the light source cover 8 is not blown out to the recording medium side! That is, the outside air is taken into the light source cover 8 from the outside air intake port 17 by the rotational drive of the air cooling fan 15 and is exhausted from the exhaust port 18 through the inside of the light source cover 8 and the housing 16.

[0026] One area of the movable range of the carriage 4 is a recording area for recording on a recording medium. Below the carriage 4 in the recording area, a platen 19 made of a flat plate-like member that supports the recording surface force of the recording medium is disposed. A transport mechanism (not shown) for transporting the recording medium in the transport direction is provided upstream or downstream of the platen 19. The transport mechanism is provided with, for example, a transport motor and a transport roller (not shown). The recording medium is transported in the transport direction by rotating the transport roller by driving the transport motor. Further, the conveyance mechanism repeats conveyance and stop of the recording medium in accordance with the operation of the carriage 4 during image recording, and conveys the recording medium intermittently.

An ink tank 20 that supplies ink to the intermediate tank 6 of the recording head 5 is provided at one end outside the recording area in the movement range of the carriage 4. The ink tank 20 is communicated with the intermediate tank 6 by an ink supply path V, not shown.

[0028] In addition, an illuminance sensor 21 as illuminance detection means for detecting the illuminance of the ultraviolet rays of the ultraviolet irradiation devices 7A and 7B is disposed at the other outer end of the recording area in the movement range of the carriage 4. ing. Further, a maintenance unit 22 that performs maintenance work of the recording head 5 is disposed on the side of the illuminance sensor 21.

Next, the control unit 23 in the present embodiment will be described with reference to FIG. The control unit 23 includes a CPU, a ROM, and a RAM (all not shown), and the processing program recorded in the ROM is expanded in the RAM and the processing program is executed by the CPU.

[0030] A transport mechanism, a carriage 4, a recording head 5, an ultraviolet irradiation device 7A, 7B, a cooling device 14, and the like are connected to the control unit 23. The control unit 23 is an operation state of various connected members. The operation of each component is controlled based on the status. In the present embodiment, the illuminance sensor 21 and the temperature sensor 13 are also connected to the control unit 23, and the control unit 23 determines whether the ultraviolet irradiation devices 7A and 7B are based on the detection results of the illuminance sensor 21 and the temperature sensor 13. The relationship between the illuminance and the base temperature of the low-pressure mercury lamps 9A and 9B is stored in RAM.

The control unit 23 is configured to be able to change the illuminance of ultraviolet rays applied to the ink ejected to the recording medium and landed on the recording medium, based on the storage means. Here, the illuminance is a force determined by the base temperatures of the low-pressure mercury lamps 9A and 9B. In the present embodiment, since the ultraviolet irradiation devices 7A and 7B are provided with the cooling devices 14, respectively, the control unit 23 The base temperature is adjusted by controlling the cooling device 14.

Here, the ink used in this embodiment will be described. In the present embodiment, when the ink is cured, the polymerization reaction of the polymerizable compound contained in the ink In the present embodiment, the ink contains an active energy ray-curable compound as the polymerizable compound. It is an ultraviolet curable ink that uses ultraviolet rays as the active energy for initiating the polymerization reaction.

[0033] The ultraviolet curable ink containing a polymerizable compound is roughly classified into a radical curable ink containing a radical polymerizable compound and a cation curable ink containing a cationic polymerizable compound. Both inks are applicable as inks used in the present embodiment. However, the cationic curable ink has little or no polymerization inhibition due to oxygen, so it has high sensitivity to ultraviolet rays, and the active species acid has the property of accumulating light energy. Therefore, it has excellent functionality and versatility.

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

[0035] First, the low-pressure mercury lamps 9A and 9B are turned on, and the carriage 4 is operated to reciprocate directly above the recording medium along the scanning direction. Then, the recording head 5 and the ultraviolet irradiation devices 7A and 7B are caused to follow the reciprocating movement of the carriage 4, and the ultraviolet irradiation devices 7A and 7B are moved above the illuminance sensor 21. The illuminance sensor 21 detects each illuminance when it is opposed to the low-pressure mercury lamps 9A and 9B. On the other hand, the temperature sensor 13 is made to detect the temperature of each cap at the time of detecting illuminance. The detection result is sent to the control unit 23, and the ultraviolet irradiation device 7 The relationship between the illuminance of A and 7B and the base temperature of the low-pressure mercury lamps 9A and 9B is stored.

[0036] The control unit 23 calculates the average value of the detected illuminance as the reference illuminance, and controls the ultraviolet irradiation devices 7A and 7B to irradiate the ultraviolet rays with the reference illuminance. That is, the control unit 23 calculates the base temperatures for irradiating the ultraviolet rays having the standard illuminance, and adjusts the base temperatures of the low-pressure mercury lamps 9A and 9B to a predetermined temperature range. Therefore, the control unit 23 controls the rotational speed of the drive motor of the air cooling fan 15 of the cooling device 14 to adjust the base temperature. Specifically, if the base temperature is too high to irradiate the reference illuminance, the number of rotations of the drive motor is increased, and the number of rotations increases until the detected temperature falls within a predetermined temperature range. Control to continue. If the die temperature is too low, the rotational speed of the drive motor is decreased, and control is performed to keep the rotational speed decreasing until the detected temperature rises and falls within a predetermined temperature range.

Here, since the control unit 23 adjusts the base temperature for each of the low-pressure mercury lamps 9A and 9B, the ultraviolet irradiation devices 7A and 7B irradiate ultraviolet rays substantially equal to the reference illuminance.

It should be noted that the reference illuminance may be an average value of the detected illuminances, and the minimum value of each of the low-pressure mercury lamps 9A and 9B may be a reference illuminance or more than a value necessary for ink curing. The reference illuminance is set in advance and can be appropriately changed by a panel operation or the like by the operator. The set specified illuminance is stored in the control unit 23.

Thus, the ink jet recording apparatus starts the image recording operation after the illuminances of the ultraviolet irradiation apparatuses 7A and 7B are made substantially uniform. When the image recording operation is started, the transport mechanism is operated to transport the recording medium along the transport direction. The carriage 4 continues to reciprocate along the scanning direction.

[0040] Then, ink is ejected from each recording head 5 by directing force toward the recording surface of the recording medium, and the recording surface of the recording medium is irradiated with ultraviolet rays from the ultraviolet irradiation devices 7A and 7B. At this time, since the illuminance of the ultraviolet rays from the ultraviolet irradiation devices 7A and 7B is substantially equal to the reference illuminance, the ultraviolet rays applied to the recording medium are uniform regardless of the position. Therefore, the ink that has landed on the recording medium has the same time for curing regardless of the landing position, so that the ink can be cured uniformly and a good image can be obtained.

[0041] By repeating such scanning, a desired image consisting of innumerable dots is satisfactorily applied to the recording medium. Recorded sequentially.

In the present embodiment, the cooling device 14 is used as the die temperature control means, but the die temperature control means is not limited to this. For example, a Peltier module in which a plurality of Peltier elements, which are thermoelectric cooling elements, are electrically connected in series is provided via a heat conduction part made of a material having high thermal conductivity and covering the periphery of the base part 12. May be. The Peltier module is designed to absorb heat from one side of the Peltier element by passing a direct current from the power supply to the Peltier element, and to dissipate the other side. The heating surface may be switched. Furthermore, when the heat conduction part abutment surface is a cooling surface on the surface facing the heat conduction part abutment surface that abuts the heat conduction part of the Peltier module, the heat absorbed and transmitted from the cooling surface is transferred. A heat sink that dissipates heat may be provided, and a cooling fan that dissipates the radiated heat may also be provided above the heat sink. When the temperature of the base part 12 is high so that the temperature of the base part 12 becomes a predetermined temperature, the control part 23 causes the heat conduction part contact surface of the Peltier module to become a cooling surface. When the power supply unit is controlled so that a direct current flows through the Peltier element and the cooling fan is driven to rotate, when the temperature of the base unit 12 is low, the heat conduction unit contact surface becomes the heating surface. The power supply may be controlled so that direct current flows through the BERCH device.

(Second embodiment)

Next, a second embodiment of the present invention will be described with reference to FIG.

Here, the ink jet recording apparatus according to the second embodiment is different from the first embodiment in the configuration of the light source provided in the ultraviolet irradiation apparatus. Describe the differences from the form.

The ultraviolet irradiation device 70 of the present embodiment includes a light source cover 8 provided with a cooling device 14 as a base temperature control means that is substantially the same as that of the first embodiment. Inside the light source cover 8, as shown in FIG. 7, a plurality of bar-shaped low-pressure mercury lamps 90 are provided. Each low-pressure mercury lamp 90 is arranged along the conveying direction, and is formed so as to have a length equal to or longer than the longitudinal dimension of the recording head 5. The low-pressure mercury lamp 90 has a structure in which both ends of a rod-like arc tube 110 are formed into a cylindrical base 12, and the base 12 is energized. As a result, the arc tube 110 emits light. Each base part 12 is provided with a temperature sensor 13 as a temperature detection means for detecting the temperature of the base part 12.

In addition, an illuminance sensor 21 serving as an illuminance detection means for detecting the illuminance of ultraviolet rays of each low-pressure mercury lamp 90 is disposed in the moving range of the carriage 4 and at the other outer end of the recording area. When the ultraviolet irradiation device 70 passes immediately above the illuminance sensor 21, the illuminance sensor 21 detects the illuminance of each of the low-pressure mercury lamps 90 that it faces.

[0046] Next, the control unit 23 in the present embodiment will be described. As in the first embodiment, the control unit 23 is composed of a CPU, a ROM, and a RAM (all not shown). The processing program recorded in the ROM is expanded in the RAM, and the CPU executes the processing program. It has become.

[0047] A transport mechanism, a carriage 4, a recording head 5, an ultraviolet irradiation device 70, a cooling device 14, and the like are connected to the control unit 23. The control unit 23 is a status such as operating statuses of various connected members. Based on the above, the operation of each component is controlled. In the present embodiment, the illuminance sensor 21 and the temperature sensor 13 are also connected to the control unit 23, and the control unit 23 is based on the detection results of the illuminance sensor 21 and the temperature sensor 13, and is a low-pressure mercury lamp for the base temperature. Each of the 90 illuminances is generated as an illuminance profile.

[0048] Based on the generated illuminance profile, the control unit 23 is configured to be able to change the illuminance of ultraviolet rays irradiated to the ink ejected to the recording medium and landed on the recording medium. Here, the illuminance is determined by the base temperature of the low-pressure mercury lamp 90. According to the present embodiment, the average value of the illuminance of the low-pressure mercury lamp 90 is calculated based on the illuminance profile. The illuminance is set as the standard illuminance. The control unit 23 calculates the base temperature of the low-pressure mercury lamp 90 that irradiates the standard illuminance, and controls the cooling device 14 so as to adjust the base temperature of the low-pressure mercury lamp 90 so that the ultraviolet light of the standard illuminance is irradiated. It is like that.

Next, the operation of this embodiment will be described.

[0050] First, the low-pressure mercury lamp 90 is turned on and the carriage 4 is operated to reciprocate directly above the recording medium in the scanning direction. The recording head 5 and the ultraviolet irradiation device 70 Is caused to follow the reciprocating movement of the carriage 4, and the ultraviolet irradiation device 70 is moved above the illuminance sensor 21. The illuminance sensor 21 detects the illuminance of each when facing the low-pressure mercury lamp 90. On the other hand, the temperature sensor 13 detects the base temperature at the time of detecting illuminance. The detection result is sent to the control unit 23, and each illuminance of the low-pressure mercury lamp 90 with respect to the base temperature is generated as an illuminance profile. The control unit 23 calculates the reference illuminance based on the generated illuminance profile, and controls the ultraviolet irradiating device 70 so as to irradiate the ultraviolet light having the reference illuminance. That is, the control unit 23 calculates the base temperature for irradiating the ultraviolet rays having the reference illuminance, and adjusts the base temperature of each low-pressure mercury lamp 90 to a predetermined temperature range. Therefore, the control unit 23 controls the rotational speed of the drive motor of the air cooling fan 15 of the cooling device 14 to adjust the base temperature.

Here, since the control unit 23 adjusts the base temperature for each low-pressure mercury lamp 90, each low-pressure mercury lamp 90 is irradiated with ultraviolet rays substantially equal to the reference illuminance.

In this manner, the ink jet recording apparatus starts the image recording operation after the illuminance of the low-pressure mercury lamp 90 is made substantially uniform. At the time of image recording, the illuminance of the ultraviolet line from the low-pressure mercury lamp 90 is substantially equal to the reference illuminance, so that the ultraviolet rays applied to the recording medium are uniform regardless of the position. Therefore, the ink that has landed on the recording medium has the same time for curing regardless of its landing position, so that the ink can be cured uniformly and a good image can be obtained.

[0053] By repeating such scanning, a desired image made up of innumerable dots is recorded sequentially and satisfactorily on a recording medium.

Although the reference illuminance is an average value of the detected illuminance, the minimum value of illuminance from each low-pressure mercury lamp 90 may be used as the reference illuminance as in the first embodiment, and the ink is cured. If it is more than the value necessary for the above, it can be changed as appropriate.

In the present embodiment, the force described for controlling the illuminance of the plurality of low-pressure mercury lamps 90 provided in the ultraviolet irradiation device 70 includes a plurality of ultraviolet irradiation devices 70 provided on the carriage 4. It is a good idea to control the illuminance of all the low-pressure mercury lamps 90 in the UV irradiator 70 in order to ensure uniform UV illuminance.

Claims

The scope of the claims

[1] a recording head for discharging ultraviolet curable ink onto a recording medium;

Illuminance detection means for detecting the illuminance of the ultraviolet irradiation device;

A control unit that controls the temperature of the base part so that the illuminance of ultraviolet rays from the plurality of ultraviolet ray irradiation devices is substantially uniform based on the detection results of the temperature detection unit and the illuminance detection unit. An ink jet recording apparatus.

[2] a recording head for discharging ultraviolet curable ink onto a recording medium;

Illuminance detection means for detecting the illuminance of the light source;

Based on the detected illuminance of the temperature detecting means and the illuminance detecting means, an illuminance distribution of ultraviolet rays from the light source with respect to the temperature of the base part is generated, and based on the generated illuminance distributions, ultraviolet rays from a plurality of the light sources are generated. An ink jet recording apparatus comprising: a control unit configured to control a temperature of the base unit so that illuminance is substantially uniform.

[3] The ink jet recording apparatus according to [1] or [2], wherein the ink is a cation polymerization type ink containing a cation polymerizable compound as a main component. .