JP2007117914A - Roller coating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a roller coating apparatus for coating a recording medium such as a paper with an arbitrary liquid by a rotating body such as a roller which solves the problem that jumboizing of the machine and redundancy of the printing time are brought about by lengthening the distance between a transport beginning of a recording sheet and a discharge point out of the machine if a route buffer is provided. <P>SOLUTION: The roller coating system which coats a particular reacting reagent on the recording medium by a roller for improving the quality of formed images at least alternatively before or after image formation by ink, toner or the like ensures a stable roller coating even if the recording medium is intermittently transported during roller coating and accelerates drying of the coated reacting reagent. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a roller coating apparatus for coating an arbitrary liquid on a recording medium such as paper by a rotating body such as a roller.

  In recent years, printers, which are representative peripheral devices, are widely used due to the spread of computers. There are various printing methods for printers, and some of them apply special reaction materials at least before or after printing in order to improve the quality and weather resistance of printed products. Among various coating methods, the roller coating method has a relatively simple structure and is suitable for miniaturization (see, for example, Patent Document 1 and Patent Document 2).

  In addition, as a printer system, an ink jet system that records an image by ejecting ink onto a recording sheet is one of those widely used because of its simple structure, small size, high quietness, and low cost. In many ink jet printers, an ink jet head that ejects ink droplets onto the surface of a recording sheet scans in a direction perpendicular to the recording sheet conveyance direction to perform printing by ejecting ink onto the recording sheet. For this reason, the recording sheet is stopped during ink discharge, that is, during scanning of the inkjet head, and is transported when scanning of the inkjet head is completed, so-called intermittent conveyance / intermittent printing is performed.

  When roller coating is combined with such a printer system that intermittently transports recording sheets, if the movement of intermittent transport of recording sheets is also performed during roller coating, the coating state changes and uniform coating is performed. It becomes difficult to do.

Therefore, for example, as disclosed in Patent Document 3, a distance equal to or longer than the length of the recording sheet in the conveyance direction is provided between the portion that performs the roller coating operation and the portion that performs the intermittent conveyance operation during printing, and the roller coating is constant. A method has been proposed in which printing is performed at a speed and printing is performed by an intermittent conveyance operation after the operation is completed.
JP-A-1-193866 JP 7-156538 A JP 2002-096453 A

  However, when the path buffer as described above is provided, there is a problem that the distance from the start of conveyance of the recording sheet to the discharge outside the apparatus becomes longer, resulting in a larger machine and redundant printing time.

In order to solve the above problems, in the present invention, an image forming means for forming an image on a recording sheet, one or more conveying means for conveying the recording sheet, and a liquid film of an image forming auxiliary liquid on a rotating body such as a roller A roller applying means for applying the image forming auxiliary liquid to the recording sheet by contacting the recording sheet, a supply means for supplying the image forming auxiliary liquid to the roller applying means, and an apparatus including the respective means Control means for comprehensively controlling the entire device, and the roller application means is present on at least one of the upstream side and the downstream side in the recording sheet conveyance direction when viewed from the image forming means, and the conveyance means In a roller coating device that intermittently conveys and stops recording sheets at arbitrary intervals,
When the recording sheet is stopped by intermittent operation of the conveying means, the air flow from the air blowing means is reduced. The recording sheet is separated from the roller application unit by the suction or blowing action, or the action of the weight of the recording sheet, and the recording sheet comes into contact with the roller application unit again when conveyance is resumed,
When the recording sheet is stopped by intermittent operation of the conveying means, the recording sheet is provided by the suction action of the suction means or the action of the weight of the recording sheet. When the recording sheet is separated from the roller application unit and the conveyance is resumed, the recording sheet comes into contact with the roller application unit again.

  As described above, in order to solve the above-described problems, in the present invention, an image forming unit that forms an image on a recording sheet, one or more conveying units that convey the recording sheet, and a rotating body such as a roller. Roller application means for applying the image formation auxiliary liquid to the recording sheet by forming a liquid film of the image formation auxiliary liquid and contacting the recording sheet; and supply means for supplying the image formation auxiliary liquid to the roller application means; Control means for comprehensively controlling the devices of the entire apparatus including the respective means, and the roller coating means is provided on at least one of the upstream side and the downstream side in the recording sheet conveying direction when viewed from the image forming means. In the roller coating apparatus that intermittently conveys and stops the recording sheet at an arbitrary interval, the conveying means includes a blower, a duct surrounding the air flow generated by the blower, and a discharge of the air flow. When the recording sheet is stopped by the intermittent operation of the conveying unit, the recording unit is provided with a sucking or blowing action of the air flow from the blowing means or the action of the weight of the recording sheet. The sheet is separated from the roller coating unit, and when the conveyance is resumed, the recording sheet comes into contact with the roller coating unit again, or has an adsorption unit capable of adsorbing the recording sheet by static electricity or the like. When the recording sheet stops due to intermittent operation, the recording sheet is separated from the roller application unit by the adsorption action of the adsorption means or the action of the recording sheet's own weight, and the recording sheet is again when the conveyance is resumed. By being in contact with the roller application means, it is possible to record the application of the image forming auxiliary liquid without impairing its function. Can be implemented in conjunction with intermittent conveyance of the sheet, it is possible to obtain the effects such as reduction of size and the total printing time of the apparatus.

Example 1
Embodiment 1 of a printer apparatus according to the present invention will be described with reference to the drawings. 1, 2, and 3 are overall configuration diagrams of a main part of the apparatus according to the present embodiment. The apparatus according to the present embodiment will be described using an ink jet method as an image recording unit.

  The apparatus of this embodiment has an ink jet head 1 as a recording means, and records an image by ejecting ink when the recording sheet S exists immediately below the recording sheet S.

  The recording sheet S is fed from the upstream direction of the first sensor 5, proceeds in the direction of arrow A as shown in the figure, and is finally discharged to the downstream side of the third roller set 4.

  The tank 31 stores the reaction liquid 30a therein. This reaction liquid 30a is applied to the printing surface side of the recording sheet S before printing by the ink jet head 1, and reacts with the ink discharged from the ink jet head 1 to finally form on the recording sheet S. It works to improve the quality of the displayed image. The reaction solution 30 a is pumped by the pump 32 through the tube 33 to the secondary liquid chamber 34. The amount of the reaction liquid 30 a in the sub liquid chamber 34 is detected by the first water level sensor 36 and the second water level sensor 37, and the pump 32 is activated when the water level of the reaction liquid falls below the second water level sensor 37. The reaction liquid 30a is sent to the auxiliary liquid chamber 34, and when the water level exceeds the first water level sensor 36, the pump 32 stops and stops pumping the reaction liquid 30a. An absorber 35 is immersed in the reaction liquid 30 a stored in the sub liquid chamber 34. The absorbent body 35 is made of a fiber and has a role of gradually exuding the reaction liquid 30a from the auxiliary liquid chamber 34 to the outside by the capillary phenomenon, and at the same time, reaction from other parts of the auxiliary liquid chamber 34. The leakage of the liquid 30a is prevented. The application roller 21 is in contact with the absorber 35. When the application roller 21 rotates, the reaction liquid 30a is transferred from the absorber 35 to the application roller 21, and the application roller 21 has a liquid film 30b of the reaction liquid 30a. Will be formed. The thickness of the liquid film 30b transferred and formed on the application roller 21 varies slightly depending on the water level of the reaction liquid 30a in the sub-liquid chamber 34, the rotation speed of the application roller 21, etc., but the water level and rotation in this embodiment. Within the range of speed and other fluctuations, the action of the reaction liquid is saturated in the state where the thickness of the liquid film 30b is the thinnest in the range, that is, in the state where the amount of the reaction liquid applied to the recording sheet is the smallest. It is assumed that there is no difference in the image finally formed on the recording sheet S even when it is applied more than that.

  In the apparatus of the present embodiment configured as described above, when the leading edge of the recording sheet S reaches the first sensor 5, the control unit 20 that controls all the devices of the apparatus detects this, The roller set 2, the second roller set 3, the third roller set 4, and the coating roller 21 are driven. When these rollers are all rotating, they are all rotated at the same peripheral speed, and the same conveying speed is given to the recording sheet S. At the same time, the blower fan 41 is activated to generate an airflow in the direction of arrow G, and the airflow is sent out from the airflow holes 42 provided in the first guide 7. The recording sheet S is nipped by the first roller set 2, proceeds in the direction of arrow A between the first guide 7 and the second guide 8, and contacts the application roller 21 by the wind pressure from the airflow hole 42 as shown in FIG. 2. Then, the liquid film 30b is applied (30c is a liquid film applied to the recording sheet S). The leading edge of the recording sheet S coated with the reaction liquid further proceeds to reach the second sensor 6. When the control unit 20 detects this, the nip of the first roller set 2 is first released as shown in FIG. 3, and then the recording sheet S is set in the second roller set until the leading end of the recording sheet S reaches directly below the inkjet head 1. 3 and the third roller set 4 are mainly responsible for conveyance and start image recording.

  In the ink jet recording method in the present embodiment, the recording sheet S is stationary, and the ink jet head 1 scans the recording sheet S in a direction perpendicular to the conveyance direction of the recording sheet S and ejects ink to a certain area on the recording sheet S. By doing so, an image is formed. Thereafter, the recording sheet S is conveyed by the amount of image recording, and intermittent conveyance / intermittent printing is performed in which the image is formed again when the portion of the recording sheet S where the image is not yet formed comes directly under the inkjet head 1. Repeated.

  When this intermittent conveyance is performed by all of the second roller set 3, the third roller set 4, and the application roller 21, how the application liquid is applied to the recording sheet by the application roller 21 is shown in FIGS. 1 will be described with reference to FIG.

During the conveyance, the liquid film 30b formed on the application roller 21 is smoothly applied to the recording sheet S as shown in FIG. However, when the conveyance is stopped, as shown in FIG. 5, among the liquid films on the coating roller 21, the liquid film near the contact point with the recording sheet S is more excessive than the recording sheet S during the normal conveyance due to capillary action. The portion J where the liquid film is completely absent or thinned appears on the application roller 21, and at the same time, the darker application portion appears in the portion K of the recording sheet S than in the normal conveyance. . Thereafter, when conveyance of the recording sheet S is resumed, as shown in FIG. 6, the recording sheet S has a normal application portion L, a thickened application portion M, and a portion N that is considerably thin or not applied at all. And this phenomenon is repeated by intermittent conveyance. (In FIGS. 4, 5, and 6, the liquid film thickness of the reaction liquid on the coating roller 21 and the coating amount on the recording sheet S are indicated by the height of the hatched portion)
However, as described above, the reaction liquid applied to the recording sheet S does not affect the final formed image as long as it is within a predetermined fluctuation range. However, if the reaction liquid is extremely small or not applied at all, it can perform its function. Absent.

  Therefore, in this embodiment, in a state where the recording sheet S is being conveyed, the recording sheet S is in contact with the application roller 21 by the wind pressure generated by the operation of the blower fan 41, but an image is being formed by the inkjet head 1. In a state where the recording sheet is stationary, the blower fan 41 is stopped and the recording sheet S is separated from the application roller 21 by its own weight, or the airflow from the blower fan 41 is reversed as shown in FIG. Then, the recording sheet S is separated from the application roller 21 by being drawn toward the guide rib 7 side. By such an action, the liquid film on the application roller 21 is prevented from coming into contact with the recording sheet S for longer than necessary time. For this reason, extra liquid film absorption due to the capillary phenomenon of the recording sheet S as described above and liquid film breakage of the application roller 21 due thereto are prevented. When the conveyance of the recording sheet S is resumed after the image formation, the blower fan again generates an air flow in the direction of arrow G to bring the recording sheet S into contact with the coating roller 21 and starts recoating. The coating roller 21 may stop rotating when the conveyance of the recording sheet S is stopped (when the recording sheet S is separated), but in consideration of prevention of evaporation of the formed liquid film, refreshing of the liquid film, and the like. It is desirable that it is always rotating.

  Here, considering the ideal state of the recording sheet S and the coating roller 21, as shown in FIG. 8 (enlarged view similar to FIGS. 4 to 6), the coated and uncoated portions of the recording sheet S are shown. The contact and separation are repeated so that the boundary portion and the boundary between the liquid film forming portion and the non-liquid film portion of the coating roller 21 are exactly aligned. Usually, there are various errors and the like. As shown in FIGS. 9, 10, and 11 (enlarged view similar to FIG. 8), the boundary portions are brought into contact with and separated from each other in a state where they are shifted to one another.

  Therefore, when the recording sheet S and the application roller 21 come into contact again, as shown in FIGS. 10 and 11, the recording sheet S is always applied slightly from the applied end of the recording sheet S even if various errors occur. The amount of rotation and the direction of rotation of each roller are controlled so that the portion entering the range comes into contact with the liquid film forming portion of the application roller 21 (so as to positively form the overlapping application portion in the minute range). The reason is that no action of the reaction material (improvement of the quality of the formed image) can be expected at the non-coated portion of the recording sheet S as shown in FIG. 9, whereas the overlapping of the minute ranges as shown in FIGS. This is because, as described above, since the action of the reaction material is saturated at the coating portion, the quality of the formed image can be improved and maintained. In addition, the range of overlap coating is very small, and it can be said that the excess amount relative to the ideal reactant consumption is negligibly small.

  Specifically, the control sequence of each device when resuming conveyance is as shown in Table 1 below (when the application roller 21 is always rotating. When the application roller 21 is stopped when conveyance of the recording sheet S is stopped). Is added to the following part 1 (content of application roller 21 starts normal rotation).

  Of course, since the control unit 20 stores the minute conveyance amount in 1 above, it is reflected in the necessary conveyance amount for the next printing.

  By such control, even when intermittent conveyance / intermittent printing is performed, reactive material roller coating is performed so as not to deteriorate the quality of the final formed image by aggressively applying a small range at the joint. Is possible.

(Example 2)
Next, a second embodiment of the printer apparatus according to the present invention will be described. Description of the same parts as those in the first embodiment is omitted.

  In the apparatus of the first embodiment, the first guide 7 is provided with the blower fan 41 and the airflow hole 42, but may be on the second guide 8 / third guide 9 side as shown in FIG. In this case, when the recording sheet S is conveyed, an air flow is generated in a direction opposite to the arrow H (so that the recording sheet S is sucked), and the coating roller 21 and the recording sheet S are brought into contact with each other. When the recording sheet S is stopped, the blower fan 41 is stopped and separated from the application roller 21 by the weight of the recording sheet S, or an air flow is generated in the direction of arrow H and is separated from the application roller 21 by wind pressure.

  The air currents from both the second guide 8 and the third guide 9 may work to contact and separate the recording sheet S and the application roller 21 in the same manner, but only one of them plays a role. You can also

  At this time, in particular, the contact / separation between the recording sheet S and the application roller 21 is assigned to the air flow from the second guide 8 side, and only the weak air flow in the direction of arrow H is blown from the third guide 9 side. (A weak airflow from the third guide 9 side does not prevent the recording sheet S and the application roller 21 from coming into contact with or separated from each other by the airflow from the second guide 8 side). According to such an action, drying of the reaction material applied to the recording sheet S can be promoted. Furthermore, it is possible to further enhance the drying effect by providing a heater or the like so that the airflow on the third guide 9 side becomes warm air.

  In addition to the means using airflow as described so far, each of the first guide 7, the second guide 8, and the third guide 9 is provided with a non-contact suction system such as an electrostatic suction device. The recording sheet S and the application roller 21 may be brought into contact with or separated from each other, or may be combined with airflow means.

  The contact force between the recording sheet S and the application roller 21 in the above description is sufficiently small with respect to the conveying force of each roller in any means, and does not hinder the conveying property and conveying accuracy of the recording sheet S. Absent.

FIG. 3 is a main part configuration diagram of the roller coating apparatus according to the first embodiment. FIG. 3 is a main part configuration diagram of the roller coating apparatus according to the first embodiment. FIG. 3 is a main part configuration diagram of the roller coating apparatus according to the first embodiment. The elements on larger scale of FIG. The elements on larger scale of FIG. The elements on larger scale of FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 3 is a partially enlarged view for explaining the roller coating apparatus according to the first embodiment. FIG. 3 is a partially enlarged view for explaining the roller coating apparatus according to the first embodiment. FIG. 3 is a partially enlarged view for explaining the roller coating apparatus according to the first embodiment. FIG. 3 is a partially enlarged view for explaining the roller coating apparatus according to the first embodiment. FIG. 5 is a configuration diagram of main parts of a roller coating apparatus according to a second embodiment.

Explanation of symbols

S recording sheet 1 inkjet head 2 first roller set 3 second roller set 4 third roller set 5 first sensor 6 second sensor 7 first guide 8 second guide 9 third guide 20 controller 21 coating roller 30a reaction liquid 30b Reaction liquid film on application roller 30c Reaction liquid on recording sheet 31 Tank 32 Pump 33 Tube 34 Sub liquid chamber 35 Absorber 36 First water level sensor 37 Second water level sensor 41 / 41b / 41c Blower fan 42 / 42b / 42c Air flow hole

Claims (8)

Image forming means for forming an image on a recording sheet, one or more conveying means for conveying the recording sheet, and an image forming auxiliary liquid by forming a liquid film of the image forming auxiliary liquid on the rotating body and contacting the recording sheet A roller coating unit that coats the recording sheet, a supply unit that supplies the image forming auxiliary liquid to the roller coating unit, and a control unit that comprehensively controls devices of the entire apparatus including the units. The roller application unit is present on at least one of the upstream side and the downstream side in the recording sheet conveyance direction as viewed from the image forming unit, and the conveyance unit intermittently conveys and stops the recording sheet at arbitrary intervals. In the roller applicator,
When the recording sheet is stopped by intermittent operation of the conveying means, the air flow from the air blowing means is reduced. Roller coating, wherein the recording sheet is separated from the roller coating unit by suction or blowing action, or by the self-weight of the recording sheet, and the recording sheet comes into contact with the roller coating unit again when transport is resumed. apparatus. In item 1,
The air blowing means comprises at least one air blowing means A arranged at the downstream side of the roller applying means with respect to the recording sheet conveyance direction C, and at least one air blowing means B arranged at other places, A roller coating apparatus, wherein the blowing means A blows air to the surface of the recording sheet on which the image forming auxiliary liquid is applied. In Section 2,
The roller coating apparatus according to claim 1, wherein the air blowing from the air blowing means A is independent of the contact / separation action between the recording sheet and the roller coating means. In the second and third terms,
The air blowing means A is provided with a heating means, and blows warm air. Image forming means for forming an image on a recording sheet, one or more conveying means for conveying the recording sheet, and an image forming auxiliary liquid by forming a liquid film of the image forming auxiliary liquid on the rotating body and contacting the recording sheet A roller coating unit that coats the recording sheet, a supply unit that supplies the image forming auxiliary liquid to the roller coating unit, and a control unit that comprehensively controls devices of the entire apparatus including the units. The roller application unit is present on at least one of the upstream side and the downstream side in the recording sheet conveyance direction as viewed from the image forming unit, and the conveyance unit intermittently conveys and stops the recording sheet at arbitrary intervals. In the roller applicator,
When the recording sheet is stopped by the intermittent operation of the conveying means, the recording sheet is applied with the roller by the suction action of the suction means or the action of the weight of the recording sheet. The roller coating apparatus is characterized in that the recording sheet comes into contact with the roller coating unit again when being separated from the unit and transport is resumed. In Section 5,
At least one blower unit E is disposed downstream of the roller coating unit with respect to the recording sheet conveyance direction C, and the blower unit E blows air to the surface of the recording sheet on which the image forming auxiliary liquid is applied. A roller coating apparatus. In Section 6,
The roller coating apparatus according to claim 1, wherein the blowing from the blowing unit E is independent of the contact / separation action between the recording sheet and the roller coating unit. In paragraphs 6 and 7,
The air blowing means E is provided with a heating means, and blows warm air.

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