JP4835268B2 - Inkjet recording device - Google Patents

Description

  The present invention relates to an ink jet recording apparatus, and more particularly to an ink jet recording apparatus that records an image while holding a recording medium on a rotating drum.

In recent years, ink jet recording apparatuses have been developed that perform image recording while holding a sheet-like recording medium on the outer peripheral surface of a rotating drum (see, for example, Patent Document 1). The rotary drum of such an ink jet recording apparatus has a plurality of suction holes formed around it, and the recording medium is attracted to the outer peripheral surface of the rotary drum by suction from the inside.
In the vicinity of the rotating drum, a heating unit is provided for heating the drum and the recording medium, and the recording medium is heated by the heating unit so that the ink landed on the surface is dried. Is promoted.
Japanese Patent Laid-Open No. 10-157299

However, since the heat capacity of the rotating drum is different depending on the location in the axial direction (particularly both end portions and the central portion), the heat radiation is different and the temperature distribution in the drum axial direction is non-uniform. Further, when the recording medium is sucked and held on the outer peripheral surface of the drum, since the covered range varies depending on the size of the recording medium, the heat radiation characteristic of the portion where the recording medium is sucked and held also varies. Furthermore, although the number of suction holes covered by the recording medium varies depending on the size of the recording medium, if there are many uncovered suction holes, the temperature drop in this part becomes severe and the outer peripheral surface of the rotating drum or The temperature distribution of the recording medium is not uniform.
In recent years, an ink jet recording apparatus using a photocurable ink has been developed. In such an apparatus, a light source for irradiating light to the photocurable ink landed on a recording medium is disposed. However, due to the radiant heat from the light source, the temperature distribution of the outer peripheral surface of the rotating drum and the recording medium is not uniform.

  If the temperature distribution becomes non-uniform due to these factors, distortion due to thermal shrinkage of the recording medium, non-uniform ink drying conditions, and non-uniform curing conditions for the photo-curable ink will result in a reduction in image quality.

  An object of the present invention is to stabilize the image quality by making the temperature of the entire rotating drum uniform.

An ink jet recording apparatus according to the invention of claim 1
A hollow rotating drum having a plurality of suction holes on the outer peripheral surface and holding the sheet-like recording medium on the outer peripheral surface via the suction holes;
A recording head for discharging ink to the recording medium held by the rotating drum;
A suction unit that applies a suction force to the suction hole by making the inside of the rotary drum negative pressure in order to attract the recording medium to the outer peripheral surface of the rotary drum;
A heating unit for heating the outer peripheral surface of the rotating drum and the recording medium held by the rotating drum;
A control unit for controlling the recording head, the suction unit, and the heating unit ;
A recognition unit for recognizing the size and suction position of the recording medium,
The heating unit is disposed over the entire width of the rotating drum, and is divided into a plurality of portions in the axial direction of the rotating drum, and is independently controlled by the control unit ,
The control unit is characterized in that the plurality of heating units are independently controlled based on the recognition result of the recognition unit such that the temperature in the axial direction of the rotating drum is uniform .

The invention described in claim 2 is the ink jet recording apparatus according to claim 1 ,
Comprising at least one temperature sensor for measuring the temperature of the recording medium held on the outer periphery of the rotary drum or on the rotary drum,
The control unit has a table that determines the heating state of the heating unit from the relationship between the size and position of the recording medium and the measurement result of the temperature sensor, and the measurement result of the temperature sensor, Based on the recognition result of the recognition unit and the table, the plurality of heating units are independently controlled so that the temperature in the axial direction of the rotating drum is uniform .

The invention described in claim 3 is the ink jet recording apparatus according to claim 1 or 2 ,
The recording head is for discharging photocurable ink onto the recording medium,
A carriage that scans the recording head in the axial direction based on the control of the control unit;
A light source that irradiates light onto the recording medium by being scanned in the axial direction in synchronization with the recording head;
The control unit independently controls the plurality of heating units based on the position of the light source by the carriage so that the axial temperature of the rotating drum is uniform.

According to a fourth aspect of the present invention, in the ink jet recording apparatus according to the third aspect ,
Comprising at least one temperature sensor for measuring the temperature of the recording medium held on the outer periphery of the rotary drum or on the rotary drum,
The control unit has a table for determining the heating state of the heating unit from the relationship between the position of the light source and the measurement result of the temperature sensor, and the measurement result of the temperature sensor, the position of the light source And based on the said table, the said several heating part is independently controlled so that the temperature of the axial direction of the said rotating body drum may become uniform.

Invention of Claim 5 is an inkjet recording device as described in any one of Claims 2-4 ,
The temperature sensor is a non-contact type sensor.

  According to the present invention, the heating unit is arranged over the entire width of the rotating drum, and is divided into a plurality of portions in the axial direction of the rotating drum, and is independently controlled by the control unit. The temperature adjustment of the body drum can be executed by subdividing it in the axial direction. Thereby, the temperature distribution in the axial direction can be made uniform, and the image quality can be stabilized.

  Hereinafter, the ink jet recording apparatus according to the present embodiment will be described with reference to the drawings. FIG. 1 is a side view illustrating a schematic configuration of the ink jet recording apparatus. As shown in FIG. 1, the ink jet recording apparatus 1 is provided with an apparatus mount 2 that supports each member for performing image recording. The apparatus base 2 is provided with a rotating drum 4 that holds the recording medium 3 on the outer peripheral surface.

  FIG. 2 is a front view illustrating a schematic configuration of the rotating drum 4. As shown in FIG. 2, the rotating drum 4 includes a rotating shaft 41 at the substantial center thereof, and the rotating drum 41 itself is rotated by a rotating mechanism 44 (see FIG. 4). It rotates at a constant speed in a predetermined rotation direction X. The rotating drum 4 is hollow inside, and a plurality of suction holes 43 formed in the outer peripheral surface of the rotating drum 4 pass through the hollow portion 42.

  The rotating drum 4 is connected to a suction portion 5 (see FIG. 4) that applies a suction force to the suction hole 43 by setting the hollow portion 42 to a negative pressure. When the suction part 5 makes the hollow part 42 have a negative pressure, a suction force is applied to the suction hole 43, and the recording medium 3 covering the surface is sucked and held on the outer peripheral surface of the rotating drum 4. Yes.

  Here, as the recording medium 3, for example, various types of paper such as plain paper, recycled paper, glossy paper, various fabrics, various non-woven fabrics, resins, metals, and other sheet-like recording media are applicable.

  As shown in FIG. 1, a carriage guide member 6 extending along the axial direction Y of the rotating drum 4 is placed on the apparatus base 2 so as to face the rotating drum 4. A carriage support member 19 that supports the carriage 7 is supported on the carriage guide member 6 so as to be capable of reciprocating scanning. The carriage support 19 is reciprocated in the sub-scanning direction Y orthogonal to the main scanning direction X along the carriage guide member 6 by a carriage moving mechanism 9 (see FIG. 4) constituted by, for example, a linear motor. Yes.

  A plurality of recording heads 8 are arranged on the carriage 7 so as to be arranged in the vertical direction. The recording head 8 discharges photocurable ink toward the recording medium 3 held on the rotating drum 4.

  A light source guide member 20 extending in the axial direction of the rotating drum 4 is disposed at a position facing the outer peripheral surface of the rotating drum 4 and downstream of the carriage 7 in the main scanning direction X. ing. The light source guide member 20 supports a light source 10 that emits ultraviolet rays as light for curing and fixing the photocurable ink landed on the recording medium 3. The light source 10 reciprocates in the sub-scanning direction Y along the light source guide member 20 in synchronization with the recording head 8 by the light source moving mechanism 11 (see FIG. 4).

  Examples of the light source 10 include a high pressure mercury lamp, a low pressure mercury lamp, a metal halide lamp, a semiconductor laser, a cold cathode lamp, an excimer lamp, or an LED.

  Further, a heating that heats the recording medium 3 and the rotating drum 4 in a non-contact manner at a position facing the outer peripheral surface of the rotating drum 4 and upstream of the carriage 7 in the main scanning direction X. A portion 12 is provided. The heating unit 12 is a radiant heater such as a halogen heater. FIG. 3 is a diagram illustrating the positional relationship between the heating unit 12 and the rotating drum 4. As shown in FIG. 3, the heating unit 12 is disposed over the entire width of the rotating drum 4 and is divided into three in the axial direction of the rotating drum 4. Hereinafter, for the sake of convenience, the heating unit 12 disposed on the left side in the drawing is referred to as a first heating unit 12a, and the heating unit 12 disposed in the center is referred to as a second heating unit 12b, which is disposed on the right side. Let the heating part 12 be the 3rd heating part 12c.

  Note that the heating unit 12 does not need to heat the recording medium 3 and the rotating drum 4 in a non-contact manner, and the position and type of the heating unit 12 are not particularly limited. For example, a sheet-like heat plate or the like may be disposed inside the rotating drum 4 as the heating unit 12 to heat the recording medium 3 from the non-recording surface side of the recording medium 3.

  As shown in FIG. 2, a non-contact temperature sensor 13 that measures the temperature of the recording medium 3 or the rotating drum 4 is provided above one end of the rotating drum 4. Since the temperature sensor 13 is non-contact, the image recorded on the recording medium 3 is not rubbed. The measurement area of the temperature sensor 13 is a part of the recording medium 3 or the rotating drum 4 facing the temperature sensor 13.

  As shown in FIG. 1, the position is opposed to the outer peripheral surface of the rotating drum 4, which is downstream of the light source 10 in the main scanning direction X and further upstream of the recording head 8 in the main scanning direction X. A pressing roller 14 that presses the recording medium 3 held on the outer peripheral surface of the rotating drum 4 is provided so as to contact the outer peripheral surface of the rotating drum 4. The pressing roller 14 is driven to rotate following the rotation of the rotating drum 4.

  Further, in the inkjet recording apparatus 1, a supply unit 15 (see FIG. 4) for supplying the recording medium 3 to the rotating drum 4 and the recording medium 3 after image recording are removed from the rotating drum 4 and discharged to the outside of the apparatus. A discharge unit 16 (see FIG. 4) is provided. The supply unit 15 recognizes the size of the storage medium 3 and the position where the recording medium 3 is attracted in the axial direction of the rotating drum 4. That is, the supply unit 15 is a recognition unit according to the present invention. Specifically, as shown in FIG. 3, the supply unit 15 has a position facing the first heating unit 12a (first position A), a position facing the second heating unit 12b (second position B), It is detected whether the recording medium 3 is attracted to any of the positions (third position C) facing the third heating unit 12c.

  FIG. 4 is a block diagram illustrating a main control configuration of the inkjet recording apparatus 1. As shown in FIG. 4, the inkjet recording apparatus 1 includes a control unit 17 that controls each unit. The control unit 17 is electrically connected to the suction unit 5, the rotation mechanism 44, the recording head 8, the carriage movement mechanism 9, the light source 10, the light source movement mechanism 11, the temperature sensor 13, the supply unit 15, and the discharge unit 16. . The control unit 17 includes a CPU, a ROM, a RAM, and the like, and the CPU controls each unit by developing a control program and control data in the ROM into the RAM.

  Moreover, the 1st heating part 12a, the 2nd heating part 12b, and the 3rd heating part 12c are separately connected to the control part 17, and each is independently controlled by the control part 17. Yes. Based on the recognition result of the supply unit 15 (the size of the recording medium 3 and the suction position of the recording medium 3) and the measurement result of the temperature sensor 13, the control unit 17 has a uniform temperature in the axial direction of the rotating drum 4. Thus, each heating unit 12 is independently controlled.

  Specifically, a temperature table (see FIGS. 5 and 6) as control data is stored in the ROM of the control unit 17. This temperature table determines the subsequent heating state of each heating unit 12 based on the adsorption position of the recording medium 3 and the measurement result of the temperature sensor 13. FIG. 5 shows a temperature table in a state where the measurement result of the temperature sensor 13 is lower than the set temperature, and FIG. 6 shows a temperature table in a state where the measurement result of the temperature sensor 13 is higher than the set temperature.

  In the temperature table of FIG. 5, when the adsorption position of the recording medium 3 is the first position A, only the first heating unit 12a is set lower than the current heating state, and the other heating units 12 are Make it higher than the current warming condition. Similarly, when the adsorption position is the second position B, only the second heating unit 12b is set lower than the current heating state, and the other heating units 12 are higher than the current heating state. When the suction position is the third position C, only the third heating unit 12c is set lower than the current heating state, and the other heating units 12 are set higher than the current heating state. .

  On the other hand, in the temperature table of FIG. 6, when the adsorption position of the recording medium 3 is the first position A, only the first heating unit 12a is turned OFF, and the other heating units 12 are in the current heating state. Also lower. Similarly, when the suction position is the second position B, only the second heating unit 12b is turned OFF, the other heating units 12 are set lower than the current heating state, and the suction position is the third position. When it is C, only the 3rd heating part 12c is turned OFF, and the other heating parts 12 are made lower than the present heating state. Thus, the control part 17 controls each heating part 12, and the temperature of the axial direction of the rotating body drum 4 is equalized.

Next, the operation of the inkjet recording apparatus 1 of the present embodiment will be described.
At the image recording start timing, the control unit 17 controls the supply unit 15 to supply the recording medium 3 to the rotating drum 4. At this time, the control unit 17 controls the rotation mechanism 44 and the suction unit 5 to perform suction by the suction unit 5 while rotating the rotating drum 4.

  When the recording medium 3 is attracted and held on the outer peripheral surface of the rotating drum 4, the control unit 17 controls the carriage moving mechanism 9 to scan the carriage 7. The control unit 17 controls the recording head 8 in synchronization with this scanning, and causes ink to be ejected onto the recording medium 3 to record an image.

  Further, the control unit 17 controls the light source moving mechanism 11 to scan the light source 10. The control unit 17 controls the light source 10 in synchronization with this scanning to irradiate the recording medium 3 with light. As a result, the ink of the recording medium 3 is cured.

  At the time of this image recording, the control unit 17 determines the heating state of each heating unit 12 based on the recognition result of the supply unit 15, the measurement result of the temperature sensor 13, and the temperature table in the ROM, and responds to the determination. Each heating unit 12 is controlled to be in a warmed state.

As described above, according to the present embodiment, the heating unit 12 is disposed over the entire width of the rotating drum 4 and is divided into a plurality of portions in the axial direction of the rotating drum 4, and the control unit 17. Therefore, the temperature adjustment of the rotating drum 4 can be performed by subdividing it in the axial direction. In particular, the suction position of the recording medium 3 is detected by the supply unit 15, and the axial temperature of the rotating drum 4 is made uniform based on the recognition result, the measurement result of the temperature sensor 13, and the temperature table. Since each heating unit 12 is independently controlled, temperature control that feeds back the current situation can be realized, and the image quality can be further stabilized.
Depending on the size and position of the recording medium 3, the air flows into the suction hole 43, which is a loss hole, to lower the temperature of this portion, and the temperature distribution of the rotating drum 4 may become non-uniform. In the embodiment, since the plurality of heating units 12 are independently controlled so that the temperature in the axial direction of the rotating drum 4 is uniform based on the recognition result of the supply unit that detects the size and suction position of the recording medium. The influence of the loss hole can be reduced, and the temperature distribution in the axial direction can be made uniform.

It is needless to say that the present invention is not limited to the above embodiment and can be modified as appropriate.
For example, in the present embodiment, the case where each heating unit 12 is independently controlled based on the adsorption position of the recording medium 3 has been described as an example. However, each heating unit 12 is independently controlled based on the position of the light source 10. Thus, it is possible to heat the rotating drum 4 so that the temperature in the axial direction becomes uniform. In this case, the control unit 17 recognizes the position of the light source 10 based on the output signal from the light source moving mechanism 11, and controls each heating unit 12 based on the position. Specifically, a temperature table for the light source position is stored in the ROM of the control unit 17 (see FIGS. 8 and 9).

  In the temperature table of FIG. 8, when the position of the light source 10 is the first position D, only the first heating unit 12a is set lower than the current heating state, and the other heating units 12 Set higher than the warmed state. Similarly, when the light source position is the second position E, only the second heating unit 12b is set lower than the current heating state, and the other heating units 12 are higher than the current heating state. When the light source position is the third position F, only the third heating unit 12c is set lower than the current heating state, and the other heating units 12 are set higher than the current heating state. .

  On the other hand, in the temperature table of FIG. 9, when the light source position of the recording medium 3 is the first position D, only the first heating unit 12a is turned OFF, and the other heating units 12 are in the current heating state. Also lower. Similarly, when the suction position is the second position B, only the second heating unit 12b is turned OFF, the other heating units 12 are set lower than the current heating state, and the suction position is the third position. When it is C, only the 3rd heating part 12c is turned OFF, and the other heating parts 12 are made lower than the present heating state. Thus, even if the control part 17 controls each heating part 12 and the position of the light source 10 fluctuates and it is influenced by radiant heat, the heating state of each heating part 12 is switched accordingly. Thus, the temperature of the rotating drum 4 in the axial direction is made uniform.

In the present embodiment, the case where the heating unit 12 is divided into three parts has been described as an example. However, four or more heating parts 12 may be dividedly arranged, and of course, the larger the number of divisions, the finer the part. Temperature control will be realized.
If two or more temperature sensors 13 are arranged in various places, the accuracy of temperature control can be further increased.

It is a side view showing the schematic structure of the inkjet recording medium which concerns on this embodiment. FIG. 2 is a front view illustrating a schematic configuration of a rotating drum provided in the ink jet recording apparatus of FIG. 1. It is a front view showing the example of arrangement | positioning of the heating part with which the inkjet recording device of FIG. 1 is equipped. FIG. 2 is a block diagram illustrating a main control configuration of the ink jet recording apparatus of FIG. 1. It is a figure showing an example of the temperature table used with the inkjet recording device of FIG. It is a figure showing an example of the temperature table used with the inkjet recording device of FIG. FIG. 2 is a diagram illustrating a relationship between a position of a light source provided in the ink jet recording apparatus of FIG. 1 and a rotating drum. It is a figure showing an example of the temperature table used with the inkjet recording device of FIG. It is a figure showing an example of the temperature table used with the inkjet recording device of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 2 Apparatus mount 3 Recording medium 4 Rotating drum 5 Suction part 6 Carriage guide member 7 Carriage 8 Recording head 9 Carriage moving mechanism 10 Light source 11 Light source moving mechanism 12 Heating part 13 Temperature sensor 14 Pressure roller 15 Supply part ( Recognition part)
Reference Signs List 16 Discharge unit 17 Control unit 19 Carriage support 20 Light source guide member 41 Rotating shaft 42 Hollow portion 43 Suction hole 44 Rotating mechanism

Claims (5)

A hollow rotating drum having a plurality of suction holes on the outer peripheral surface and holding the sheet-like recording medium on the outer peripheral surface via the suction holes;
A recording head for discharging ink to the recording medium held by the rotating drum;
A suction unit that applies a suction force to the suction hole by making the inside of the rotary drum negative pressure in order to attract the recording medium to the outer peripheral surface of the rotary drum;
A heating unit for heating the outer peripheral surface of the rotating drum and the recording medium held by the rotating drum;
A control unit for controlling the recording head, the suction unit, and the heating unit ;
A recognition unit for recognizing the size and suction position of the recording medium,
The heating unit is disposed over the entire width of the rotating drum, and is divided into a plurality of portions in the axial direction of the rotating drum, and is independently controlled by the control unit ,
The control unit independently controls the plurality of heating units so that the axial temperature of the rotating drum is uniform based on a recognition result of the recognition unit. The inkjet recording apparatus according to claim 1 , wherein
Comprising at least one temperature sensor for measuring the temperature of the recording medium held on the outer periphery of the rotary drum or on the rotary drum,
The control unit has a table that determines the heating state of the heating unit from the relationship between the size and position of the recording medium and the measurement result of the temperature sensor, and the measurement result of the temperature sensor, An inkjet recording apparatus , wherein the plurality of heating units are independently controlled based on a recognition result of a recognition unit and the table so that the temperature in the axial direction of the rotating drum is uniform . The inkjet recording apparatus according to claim 1 or 2 ,
The recording head is for discharging photocurable ink onto the recording medium,
A carriage that scans the recording head in the axial direction based on the control of the control unit;
A light source that irradiates light onto the recording medium by being scanned in the axial direction in synchronization with the recording head;
The ink jet recording apparatus, wherein the control unit independently controls the plurality of heating units so that the temperature in the axial direction of the rotating drum is uniform based on the position of the light source by the carriage. The inkjet recording apparatus according to claim 3 .
Comprising at least one temperature sensor for measuring the temperature of the recording medium held on the outer periphery of the rotary drum or on the rotary drum,
The control unit has a table for determining the heating state of the heating unit from the relationship between the position of the light source and the measurement result of the temperature sensor, and the measurement result of the temperature sensor, the position of the light source And the plurality of heating units are independently controlled based on the table so that the axial temperature of the rotating drum is uniform. In the ink jet recording apparatus according to any one of claims 2 to 4 ,
The ink jet recording apparatus, wherein the temperature sensor is a non-contact sensor.

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