Printing apparatus

A printing apparatus includes a coater, a first discharger, a first dryer, a second discharger, and a second dryer. The coater applies a coating liquid to both faces of a sheet material. The first discharger discharges a first liquid to one face of the sheet material with the coating liquid applied to both faces of the sheet material. The first dryer dries the sheet material to which the first liquid discharged from the first discharger is applied. The second discharger discharges a second liquid to the other face of the sheet material that has passed through the first dryer. The second dryer dries the sheet material to which the second liquid discharged by the second discharger is applied.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is based on and claims priority pursuant to 35 U.S.C. § 119(a) to Japanese Patent Application No. 2019-228372, filed on Dec. 18, 2019, in the Japan Patent Office, the entire disclosure of which is incorporated by reference herein.

BACKGROUND

Technical Field

Aspects of the present disclosure relate to a printing apparatus.

Related Art

Generally, there is an apparatus that applies treatment liquid to both faces of a sheet material with a coating device and performs printing on the sheet material.

SUMMARY

In an aspect of the present disclosure, there is provided a printing apparatus including a coater, a first discharger, a first dryer, a second discharger, and a second dryer. The coater applies a coating liquid to both faces of a sheet material The first discharger discharges a first liquid to one face of the sheet material with the coating liquid applied to both faces of the sheet material. The first dryer dries the sheet material to which the first liquid discharged from the first discharger is applied. The second discharger discharges a second liquid to the other face of the sheet material that has passed through the first dryer. The second dryer dries the sheet material to which the second liquid discharged by the second discharger is applied.

DETAILED DESCRIPTION

First, a printing apparatus according to a first embodiment of the present disclosure is described with reference toFIG. 1.FIG. 1is a schematic view illustrating the printing apparatus according to the first embodiment of the present disclosure.

The printing apparatus1includes an unwinding device10, a coating device20, a first discharge device50A, a first drying device60A, a second discharge device50B, a second drying device60B, and a winding device90.

The unwinding device10is a carry-in unit to unwinding and carrying in a sheet material P, which is a web such as continuous form sheet, from an original winding roller11. The coating device20is a pre-treatment unit to apply treatment liquid as coating liquid on both sides of the sheet material P conveyed from the unwinding device10.

The first discharge device50A is a printing unit including a first discharger to discharge and print liquid containing colorant on one face of a sheet material P coated with the treatment liquid on both faces of the sheet material by the coating device20. The first drying device60A is a drier to heat and dry the sheet material P on which the liquid is discharged by the first discharge device50A.

The second discharge device50B is a printing unit including a second discharger to discharge and print liquid containing colorant on the other face of the sheet material P heated in the first drying device60A. The second drying device60B is a drier to heat and dry the sheet material P on which the liquid is discharged by the second discharge device50B.

The winding device90is a carry-out unit to wind the sheet material P, which is dried by passing through the second drying device60B, onto the winding roller91.

Next, an example of the first discharge device50A and the second discharge device50B is described with reference toFIG. 2.FIG. 2is an illustration of the discharger of each of the above-described discharge devices.

Each of the first discharge device50A and the second discharge device50B includes a discharger500. The discharger500of the first discharge device50A is referred to as a first discharger, and the discharger500of the second discharge device50B is referred to as a second discharger.

In the discharger500, full-line type head arrays551A,551B,551C, and551D for four colors (hereinafter referred to as “head array551” when colors are not distinguished), are arranged from the upstream side in a conveyance direction of a sheet material P.

Each head array551is a liquid discharger and discharges liquid of black (K), cyan (C), magenta (M), or yellow (Y) to the sheet material P to be conveyed. Note that the type and number of color are not limited to the above-described four colors.

The head array551includes, for example, liquid discharge heads (which are also simply referred to as “heads”)100arranged in a zigzag manner on a base member552. However, the arrangement of heads is not limited to such arrangement.

Next, an example of the coating device20is described with reference toFIGS. 3 and 4.FIG. 3is an illustration of the coating device20, andFIG. 4is an illustration of a coater of the coating device20.

The coating device20includes a first coater21A, a second coater21B, a plurality of guide rollers23, a cutter mechanism24, and so forth. Furthermore, the coating device20has an S-shaped conveyance path25immediately upstream from an outlet in the conveyance direction of the sheet material P to enhance the running stability of the sheet material P.

The first coater21A is a treatment liquid applicator to apply treatment liquid201as coating liquid on one face (front face) of the sheet material P being conveyed. The second coater21B is a treatment liquid applicator to apply the treatment liquid201on the other face (back face) of the sheet material P.

The first coater21A and the second coater21B are configured with a coater200illustrated inFIG. 4.

The coater200includes a treatment liquid container202to contain the treatment liquid201. The treatment liquid container202may be integrated with a case member203that is a housing of the coater200.

The coater200includes a transfer roller205and a coating roller206. The transfer roller205is accommodated in the treatment liquid container202to scoop the treatment liquid201. The coating roller206applies the treatment liquid201to the sheet material P after the treatment liquid201is transferred onto the coating roller206by the transfer roller205. The transfer roller205is rotated at a speed slightly slower than the conveyance speed of the sheet material P.

Further, the coater200includes a pressure roller207to press the sheet material P facing the coating roller206and a pressure adjusting device208to adjust the pressing pressure of the pressure roller207.

In the coater200, the transfer roller205transfers the treatment liquid201onto the surface of the coating roller206in the shape of a thin film.

Then, the coating roller206is pressed against the rotating pressure roller207to rotate the coating roller206. At this time, the coater200conveys the sheet material P into a gap between the coating roller206and the pressure roller207to apply the treatment liquid201onto the surface of the sheet material P.

The pressure adjusting device208controls the nip pressure arising when the treatment liquid201is applied to the sheet material P (i.e., the pressure acting at a position where the coating roller206and the pressure roller207are in contact with each other). The applied amount (application amount, film thickness, liquid amount, adhesion amount, dry adhesion amount, etc.) of the treatment liquid201can be adjusted by changing the nip pressure using the pressure adjusting device208.

Further, the applied amount of the treatment liquid201can be also controlled by changing the rotational speeds of the coating roller206and the pressure roller207.

A liquid of which the agglutination reaction with the ink does not change significantly in either a wet state or a dry state, is used as the treatment liquid201. For example, a pre-coating liquid as described in JP-2019-019315-A may be used.

Next, an example of the drier constituting each of the first drying device and the second drying device is described with reference toFIG. 5.FIG. 5is an illustration of the drier of each of the above-described drying devices. Note that, inFIG. 5, the rotating bodies having the same function are indicated with the same hatch or dot pattern, and the reference numerals are omitted.

Each of the first drying device60A and the second drying device60B includes a drier600. The drier600of the first drying device60A is referred to as a first drier, and the drier600of the second drying device60B is referred to as a second drier.

The drier600includes a plurality of heating rollers611and a heating drum612to heat a sheet material P in contact with the sheet material P. Further, the drier600includes a plurality of guide rollers613to guide the sheet material P so that the sheet material P contacts necessary heating rollers611among the plurality of heating rollers611.

A heating conveyance path (or a conveyance path) for heating the sheet material P is configured by the plurality of heating rollers611, the heating drum612, and the plurality of guide rollers613. The sheet material P is conveyed while contacting the outer peripheral side of the plurality of heating rollers611arranged in an arc shape on the upstream side of the heating drum612in the conveyance direction of the sheet material P. Then, the sheet material P passes through the heating drum612, and is conveyed by the guide roller613while contacting the inner peripheral side of the plurality of heating rollers611.

In other words, in the present embodiment, the sheet material P is brought into contact with the heating roller611from different directions and heated by the heating rollers611.

Further, in the drier600, a plurality of non-contact heating units616that heats the sheet material P from a liquid applied face side are arranged on the outer peripheral side of the arrangement of the plurality of heating rollers611, and a plurality of non-contact heating units616are also arranged around the heating drum612. The non-contact heating unit616can be configured with, for example, an air blowout unit or an infrared (IR) heater. Note that, in the present embodiment, “liquid applied face” refers to a face on which liquid has been applied by discharge of the discharger500of the first discharge device50A or the second discharge device50B.

Further, the drier600includes a plurality of guide rollers617that guides the sheet material P to carry the sheet P into and out the drier600.

As the flow of a drying process in the drier600thus configured, the non-contact heating units616, for example, blow air to the liquid applied face to heat the liquid applied face, while the opposite face of the liquid applied face of the sheet material P is brought into contact with and heated by the heating rollers611.

Then, the non-contact heating units616, for example, blow air to the liquid applied face to heat the liquid applied face, while the opposite face of the liquid applied face of the sheet material P is brought into contact with and heated by the heating drum612, which is disposed inside the arrangement of the plurality of heating rollers611.

Thereafter, while the guide rollers613are brought into contact with the liquid applied face of the sheet material P, the heating rollers611contact the face opposite to the liquid applied face of the sheet material P and heats the sheet material P to dry the liquid applied to the sheet material P.

At this time, the treatment liquid201applied to both faces of the sheet material P by the coating device20is also dried, and the treatment liquid201is in a dry state.

As above described, the printing apparatus1includes the coating device20including the first coater21A and the second coater21B, each of which is configured with the coater200that applies the coating liquid (treatment liquid201) on both faces of the sheet material P.

The printing apparatus1further includes the first discharge device50A and the first drying device60A. The first discharge device50A receives the sheet material P, in which the treatment liquid201is applied on both faces by the coating device20, as it is and discharges liquid to one face of the sheet material P. The first drying device60A dries the sheet material P applied with the liquid in the first discharge device50A.

Further, the printing apparatus1includes the second discharge device50B and the second drying device60B. The second discharge device50B discharges liquid to the other face of the sheet material P having passed through the first drying device60A. The second drying device60B dries the sheet material P applied with the liquid which is discharged in the second discharge device50B.

Thus, in the printing apparatus1, the coating liquid is applied to both faces of the sheet material P, the liquid is discharged to the sheet material P conveyed to the first discharge device50A, which is the first discharger, without being heated, and then printing and drying are performed. As a result, the coating liquid applied to the sheet material P and the printing liquid applied in the first discharge device50are dried. Thereafter, the liquid is discharged in the second discharge device50B, which is the second discharger, on the other face of the sheet material P, and then printing and drying are performed.

In other words, there is no means for heating the sheet material P between the coating device20, which is the coater, and the first discharge device50A, which is the first discharger. The first drying device60A, which is the first drier, is disposed between the first discharger and the second discharger.

In other words, the printing apparatus1has the following configuration: the coating liquid is applied, liquid is discharged from the first discharge device50A serving as the first discharger to the sheet material P, which is not heated. The coating liquid is applied in the coater, and then liquid is discharged from the second discharge device50B, which is the second discharger, to the sheet material P which is heated.

Further, the first discharge device50A, which is the first discharger, discharges the liquid to the sheet material P in a wet state, and the second discharge device50B, which is the second discharger, discharges the liquid to the sheet material P on which the coating liquid is in a dry state.

As a result, the sheet material P, to which the coating liquid is applied and the printing liquid is discharged by the first discharger, is prevented from being sent to the second discharger and applied further liquid in an undried state, and thus print quality is enhanced.

Further, since the coating device20does not include a drying section to dry a sheet material P on which the treatment liquid is applied on both faces, the height of the coating device20can be restrained to be lower than the height of the first discharge device50A.

As a result, as illustrated inFIG. 6A, a field of view AR is prevented from being disturbed by the coating device20when viewed from the upstream side of the unwinding device10along the conveyance direction of the sheet material P, and a rotating lamp (revolving warning light)70disposed above the first discharge device50A is visible.

On the other hand, as illustrated inFIG. 6B, when the height of the coating device20is high, the field of view AR is blocked by the coating device20, and the rotating lamp70disposed above the first discharge device50A is invisible.

In the above-described embodiment, the example of the printing apparatus1that performs printing on a web-shaped sheet material is described. However, a printing apparatus in an embodiment of the present disclosure is not limited to such a printing apparatus and may be, for example, a printing apparatus that performs printing on a cut sheet or a large-format cut sheet such as a wallpaper.