JP2007320243A - Inkjet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize an image quality by uniforming a temperature of the whole of a rotary drum by warming at the standby time. <P>SOLUTION: The inkjet recorder is equipped with the hollow-shaped rotary drum which holds a sheet-like recording medium at the peripheral surface, a recording head which ejects ink to the recording medium, a rotating mechanism for rotating the rotary drum, a suction part which gives a suction force to a suction hole by turning the inside of the rotary drum a negative pressure so as to make the recording medium sucked and stuck to the peripheral surface of the rotary drum, a warming part which warms the rotary drum while being opposed to a part of the peripheral surface of the rotary drum, and a control part which controls the recording head, rotating mechanism, suction part and warming part. The control part controls the rotating mechanism to rotate the rotary drum in the case of a standby state in which the recording medium is not stuck to the rotary drum. <P>COPYRIGHT: (C)2008,JPO&INPIT

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

  By the way, since the heat capacity of the entire rotating drum is large, it is necessary to increase the image quality immediately after resuming image recording by heating the rotating drum even during standby. However, the rotating drum does not rotate during standby, and the temperature distribution in the circumferential direction becomes non-uniform. If the temperature distribution becomes non-uniform, distortion due to thermal contraction of the recording medium, non-uniform ink drying conditions, and non-uniform curing conditions for the photocurable ink will result in unstable image quality.

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

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 rotating mechanism for rotating 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 that heats the rotating drum, facing a part of the outer peripheral surface of the rotating drum,
A control unit for controlling the recording head, the rotation mechanism, the suction unit, and the heating unit;
The control unit controls the rotating mechanism while controlling the heating unit to heat the rotating drum when the recording medium is not adsorbed to the rotating drum. The rotating drum is rotated.

The invention described in claim 2 is the ink jet recording apparatus according to claim 1,
In the standby mode, the control unit controls the heating unit so as to be smaller than the heating value of the heating unit during image recording.

The invention described in claim 3 is the ink jet recording apparatus according to claim 1 or 2,
Comprising at least one temperature sensor for measuring the temperature of the rotating drum;
The control unit controls the heating unit based on a measurement result of the temperature sensor.

According to a fourth aspect of the present invention, in the ink jet recording apparatus according to the third aspect,
The temperature sensor is a non-contact type sensor.

Invention of Claim 5 is an inkjet recording device as described in any one of Claims 1-4,
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. .

Invention of Claim 6 is an inkjet recording device as described in any one of Claims 1-5,
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;
And a light source that irradiates light onto the recording medium by scanning in the axial direction in synchronization with the recording head.

  According to the present invention, in the standby state where the recording medium is not attracted to the rotating drum, the rotating drum is rotated, so that the outer peripheral surface of the rotating drum is sequentially heated by the heating unit. Will be. As a result, the temperature of the entire rotating drum can be made uniform even during standby, distortion due to thermal shrinkage of the recording medium wound thereafter can be suppressed, and as a result, the image quality can be stabilized. it can.

  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 papers such as plain paper, recycled paper, glossy paper, various fabrics, various non-woven fabrics, various recording materials such as resin, metal, and the like 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 unit 12 for heating the rotating drum 4 in a non-contact manner is provided 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. It has been. 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 so as to face a part of the outer peripheral surface of the rotating drum 4.

  In addition, the heating part 12 does not need to heat the rotary drum 4 in a non-contact manner, and the position and type of the heating part 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. The pressing roller 14 is used to bring the recording medium 3 into close contact with the outer peripheral surface of the rotating drum 4, and comes into contact with the rotating drum 4 as the rotating drum 4 is rotated by the rotating mechanism 44. It is designed to be separated.

  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.

  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.

  At the time of image recording, the controller 17 turns off the heating unit 12 when the temperature measured by the temperature sensor 13 is higher than the set temperature, and sets the heating unit 12 to a high temperature state (H) when the temperature is lower than the set temperature. Next, the heating unit 12 is controlled.

  Further, the control unit 17 determines whether or not the recording medium 3 is present on the outer peripheral surface of the rotating drum 4 from the current operation, and if not, determines that the recording medium 3 is in a standby state and the heating unit 12. The amount of generated heat is made lower than the amount of generated heat during image recording. Here, the operation for determining that the recording medium 3 is present on the outer peripheral surface of the rotating drum 4 is when recording an image, winding the recording medium, and the like. It is determined that the recording medium 3 does not exist. When it is determined that the temperature does not exist, the control unit 17 turns off the heating unit 12 when the temperature measured by the temperature sensor 13 is higher than the set temperature, and sets the heating unit 12 in a low temperature state (L ) To control the heating unit 12.

  Further, even when the recording medium 3 is present on the outer peripheral surface of the rotating drum 4, even when it is determined that the recording medium is being wound, the heating amount of the heating unit 12 is larger than the heating amount at the time of image recording. Reduce. Specifically, the control unit 17 turns off the heating unit 12 when the temperature measured by the temperature sensor 13 is higher than the set temperature, and sets the heating unit 12 to a low temperature state (L) when the temperature is equal to or lower than the set temperature. The heating unit 12 is controlled.

  Next, the operation of the inkjet recording apparatus 1 of the present embodiment will be described. FIG. 5 is a timing chart showing the heating state of the heating unit 12.

  When the image recording start timing comes, the control unit 17 controls the supply unit 15 to supply the recording medium 3 to the rotating drum 4. Here, the control unit 17 determines that the recording medium 3 is in a standby state until the recording medium 3 is positioned in the vicinity of the rotating drum 4, and controls the rotating mechanism 44 to rotate the rotating drum 4 at a lower speed than during image recording. The suction unit 5 is controlled and stopped. And the control part 17 controls the heating part 12 based on the measurement result and preset temperature of the temperature sensor 13, and heats the rotary drum 4 at the time of standby.

  When the recording medium 3 moves to the vicinity of the rotating drum 4, the control unit 17 determines the winding timing and controls the rotating mechanism 44 to temporarily stop the rotating drum 4. After this stop, the control unit 17 controls the supply unit 15 to move the recording medium 3 to the reference position of the rotating drum 4. Thereafter, the control unit 17 controls the suction unit 5 to start suction, and also controls the rotation mechanism 44 and the supply unit 15 to synchronize the rotation of the rotating drum 4 and the supply of the recording medium 3. Then, the recording medium 3 is attracted to a predetermined position of the rotating drum 4. At this time, since the control unit 17 controls the rotation mechanism 44 to bring the pressing roller 14 into contact with the rotating drum 4, the recording medium 3 is attracted to the outer peripheral surface of the rotating drum 4 without any gap. It will be. When the adsorption is completed, the control unit 17 controls the rotation mechanism 44 to stop the rotation of the rotating drum 4 and separates the pressing roller 14 from the rotating drum 4. Also at this time, the control unit 17 controls the heating unit 12 based on the measurement result of the temperature sensor 13 and the set temperature to heat the rotating drum 4. When the rotating drum 4 is stopped, the control unit 17 controls the heating unit 12 to stop the heating of 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 the heating unit 12 based on the measurement result of the temperature sensor 13 and the set temperature, and the heating unit 12 so as to be in the heating state according to the determination. Is controlling.

  As described above, according to the present embodiment, when the rotating drum 4 is rotated in the standby state, the outer peripheral surface of the rotating drum 4 is sequentially heated by the heating unit 12. Become. As a result, the temperature of the entire rotating drum 4 can be made uniform in the circumferential direction even during standby, and distortion caused by thermal contraction of the recording medium wound thereafter is suppressed, resulting in stabilization of image quality. be able to.

  Further, since the suction unit 5 is stopped during standby and the rotational speed of the rotating drum 4 is lower than that during image recording, the amount of heat released from the rotating drum 4 is greater than that during image recording. Reduced. For this reason, even if the amount of heat generated by the warming unit 12 in the standby state is lower than that during image recording, the temperature distribution in the circumferential direction of the rotating drum 4 is prevented from becoming uneven.

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 the heating unit 12 is disposed over the entire width of the rotating drum 4 has been described as an example, but there are a plurality of heating units 12 in the axial direction of the rotating drum 4. It may be divided and arranged. In such a case, each heating unit 12 can be independently controlled by the control unit 17. If independent control can be performed, even when the temperature distribution becomes non-uniform in the axial direction of the rotating drum 4, it is possible to heat independently corresponding to the temperature distribution. Therefore, the temperature of the entire rotating drum 4 can be made uniform, and distortion due to thermal contraction of the recording medium can be further suppressed.
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 timing chart showing the heating state of the heating part of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 2 Apparatus mount 3 Recording medium 4 Rotor 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 Pressing roller 15 Supply part 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 (6)

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 rotating mechanism for rotating 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 that heats the rotating drum, facing a part of the outer peripheral surface of the rotating drum,
A control unit for controlling the recording head, the rotation mechanism, the suction unit, and the heating unit;
The control unit controls the rotating mechanism while controlling the heating unit to heat the rotating drum when the recording medium is not adsorbed to the rotating drum. An ink jet recording apparatus, wherein the rotating drum is rotated. The inkjet recording apparatus according to claim 1, wherein
In the standby mode, the control unit controls the heating unit so as to be smaller than the amount of heat generated by the heating unit during image recording. The inkjet recording apparatus according to claim 1 or 2,
Comprising at least one temperature sensor for measuring the temperature of the rotating drum;
The ink jet recording apparatus, wherein the control unit controls the heating unit based on a measurement result of the temperature sensor. The inkjet recording apparatus according to claim 3.
The ink jet recording apparatus, wherein the temperature sensor is a non-contact sensor. In the ink jet recording apparatus according to any one of claims 1 to 4,
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. Inkjet recording device. In the ink jet recording apparatus according to any one of claims 1 to 5,
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;
An ink jet recording apparatus comprising: a light source that emits light onto the recording medium by being scanned in the axial direction in synchronization with the recording head.

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