The present application is based on, and claims priority from JP Application Serial Number 2019-198480, filed Oct. 31, 2019, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to an ink jet recording method and an ink jet recording apparatus.

2. Related Art

Since being capable of recording a highly fine image by a relatively simple apparatus, an ink jet recording method has been rapidly developed in various fields. In particular, various types of investigations on ejection stability and the like have been carried out. For example, JP-A-2015-147405 has disclosed a recording method which includes steps of sequentially adhering a first reaction liquid, a first ink containing a colorant, a second reaction liquid, and a second ink containing a colorant to a non-absorptive recording medium or a low-absorptive recording medium so as to be overlapped with each other. In the recording method described above, the first reaction liquid contains an aggregating agent which aggregates a component of the first ink or which increases the viscosity thereof, and the second reaction liquid contains an aggregating agent which aggregates a component of the second ink or which increases the viscosity thereof.

In an ink jet recording method, when recording is performed using an aqueous ink composition and a treatment liquid containing an aggregating agent, a component of the aqueous ink composition is aggregated, and the aqueous ink composition is rapidly solidified, so that an excellent image quality can be obtained. However, in a recording method using a treatment liquid, a white haze is generated in a recorded matter. In order to suppress the generation of white haze while an excellent image quality is obtained, the ink jet recording method using a treatment liquid containing an aggregating agent is still required to be improved.

SUMMARY

In order to solve the problem described above, the present inventors carried out intensive research. As a result, it was found that by the following ink jet recording method which uses a treatment liquid containing an aggregating agent, while an excellent image quality is obtained, the generation of white haze can be suppressed. The ink jet recording method described above includes a first heating step, a second heating step, and, after the first heating step and before the second heating step, a cooling step of cooling a recording medium by a cooling mechanism, and in the cooling step described above, a surface temperature of the recording medium is decreased to a temperature lower than a surface temperature in the first heating step.

That is, the present disclosure is as described below.

According to an aspect of the present disclosure, there is provided an ink jet recording method comprising: a treatment liquid adhesion step of adhering a treatment liquid containing an aggregating agent to a recording medium; an ink adhesion step of adhering an aqueous ink composition containing a colorant to the recording medium by ejection thereof from an ink jet head; a first heating step of heating the recording medium to which the treatment liquid and the aqueous ink composition are adhered to a first surface temperature by a first heating mechanism; a second heating step of heating the recording medium after the first heating step to a second surface temperature which is higher than the first surface temperature by a second heating mechanism provided at downstream than the first heating mechanism in a recording medium transport direction; and a cooling step of, after the first heating step and before the second heating step, cooling the recording medium by a cooling mechanism, and by the cooling step, a surface temperature of the recording medium is decreased to a temperature lower than the first surface temperature.

According to another aspect of the present disclosure, there is provided an ink jet recording apparatus comprising: a transport mechanism which transports a recording medium; a treatment liquid adhesion portion which adheres a treatment liquid containing an aggregating agent to the recording medium; an ink jet head which adheres an aqueous ink composition containing a colorant to the recording medium by ejection thereof; a first heating mechanism which heats the recording medium to which the treatment liquid and the aqueous ink composition are adhered to a first surface temperature; a second heating mechanism which heats the recording medium heated by the first heating mechanism to a second surface temperature higher than the first surface temperature and which is provided at downstream than the first heating mechanism in a recording medium transport direction; and a cooling mechanism which cools the recording medium at downstream than the first heating mechanism and at upstream than the second heating mechanism in the recording medium transport direction, and the cooling mechanism decreases a surface temperature of the recording medium to a temperature lower than the first surface temperature.

The cooling mechanism may include an air blow mechanism. The air blow mechanism may supply a wind at a wind velocity of 1 m/sec or more. The first surface temperature may be 28° C. to 45° C., and by the cooling step, the surface temperature of the recording medium may be decreased to 20° C. to 34° C. The second surface temperature may be 60° C. or more. A time after the first heating step to a start of the second heating step may be 20 seconds or more. The recording medium may contain a sulfate salt as a material forming a recording surface. A temperature after the cooling step may be lower than the first surface temperature by 3° C. or more. A content of the aggregating agent in the treatment liquid may be 2.0 to 10.0 percent by mass. The aggregating agent may contain a polyvalent metal salt, an organic acid, or a cationic polymer. The treatment liquid may be an aqueous composition and may contain 20.0 percent by mass or more of an organic solvent. The aqueous ink composition may contain 20.0 percent by mass or more of an organic solvent.

