30 will be described in more detail with reference to FIGS. 3 to 5.

As illustrated in FIG. 5, when the output signal of the passage sensor S1 passes through the rear end of the first medium M1 illustrated in FIG. 3, the output signal of the passage sensor S1 is switched from an ON signal (a state in which the medium M is detected) to an OFF signal (a state in which the medium M is not detected) (time t1).

Thereafter, when the output signal of the passage sensor S1 passes through the leading end of the second medium M2 shown in FIG. 4 after a time interval of, for example, 60 msec, the output signal of the passage sensor S1 is switched from the OFF signal to the ON signal (time t2).

As illustrated in FIG. 3, when the first medium M1 leans against the top fence 33, the leaning sensor S2 continuously outputs an ON signal (a state in which leaning is detected) (time t3 to time t5).

Then, for example, when the ON signal of the leaning sensor S2 is continuously output until the rear end of the second medium M2 illustrated in FIG. 4 passes through the passage sensor S1 (time t4), the control unit 38a vibrates the end fence 32 and the top fence 33 in the vibration direction D1 parallel to the transport direction A (time t5 to time t7). For example, the amplitude of the vibration of the end fence 32 and the top fence 33 is 4 mm (preferably, within 10 mm), and the vibration within 0.1 seconds (preferably, within 1 second) per one time is preferably continued 10 times or more. The vibration of the end fence 32 and the top fence 33 continues until after the leading end of the third medium M (not illustrated) passes through the passage sensor S1 (time t6).

As a result, as illustrated in FIG. 4, the leaning of the first medium M against the top fence 33 is eliminated (time t5 in FIG. 5). Here, even after the vibration of the end fence 32 and the top fence 33 has ended (time t7), when the leaning of the medium M is not eliminated (for example, if the leaning sensor S2 outputs an ON signal even when the rear end of the next (third) medium M has passed through the passage sensor S1), the control unit 38a may increase the amount of vibration of the end fence 32 and the top fence 33. For example, the amount of vibration may be increased by increasing the amplitude of vibration, increasing the vibration speed (increasing the vibration frequency), or increasing the vibration time. Alternatively, the control unit 38a may extend the specified vibration period (times t5 to t7) of the end fence 32 and the top fence 33, for example, until the leaning of the medium M is eliminated. Thereafter, in cases where the leaning of the medium M is not eliminated even if the plurality of media M passes through the passage sensor S1, it is preferable to issue an error notification to the user, stop the transport (printing) of the medium M, or the like.

In addition, increasing the amount of vibration of the end fence 32 and the top fence 33 is not limited to the case where the leaning of the medium M is not eliminated, and may be performed based on the medium information such as the size, direction, type, transport speed, and positional deviation on the upstream side in the transport direction A of the medium M described above. For example, the amount of vibration may be increased for the medium M whose leaning is difficult to eliminate due to the material of the medium M and the like. Alternatively, the control unit 38a may reduce the amount of vibration or determine whether or not to vibrate the end fence 32 and the top fence 33 based on the medium information.

In addition, the amount of vibration may be increased based on environmental information such as temperature detected by a temperature sensor and humidity detected by a humidity sensor. For example, in an environment of high temperature and high humidity, it is difficult to eliminate the leaning of the medium M. Accordingly, the amount of vibration may be increased. Alternatively, when area information can be acquired from the installation area or the like set in the medium loading device 30 (or the printing apparatus 10), the amount of vibration may be increased based on the environmental information assumed from the area information. For example, in an installation area with relatively high temperature and high humidity, the leaning of the medium M is less likely to be eliminated as compared with an installation area where the temperature and humidity are not relatively high. Therefore, the amount of vibration may be increased. Alternatively, the control unit 38a may reduce the amount of vibration or determine whether or not to vibrate the end fence 32 and the top fence 33 based on the environmental information.

In addition, in the example of FIG. 5, a period in which the end fence 32 vibrates and a period in which the top fence 33 vibrates are the same (time t5 to time t7). However, when one of the end fence 32 and the top fence 33 vibrates and then the other one vibrates, the medium M is more likely to be aligned and loaded than in a case where both vibrate simultaneously. Therefore, the disturbance of the loading state is less likely to occur. In addition, even if the period in which the end fence 32 vibrates and the period in which the top fence 33 vibrates partially overlap each other, the disturbance of the loading state is less likely to occur as compared with the case where the periods overlap each other as a whole.

Incidentally, FIG. 3 illustrates an example in which the first medium M1 leans against the top fence 33, but the medium M may also lean against the end fence 32. Since the leaning sensor S2 cannot determine which one of the end fence 32 and the top fence 33 the medium M leans against, even when the medium M leans against the end fence 32, the above-described operation in which both the end fence 32 and the top fence 33 vibrate is performed.

However, in a case where the leaning sensor S2 is a reflection sensor, a displacement sensor, a contact sensor, or the like, it is possible to determine to which of the end fence 32 and the top fence 33 the medium M is leaning. In this case, the control unit 38a may vibrate only the end fence 32 when the leaning of the medium M against the end fence 32 is detected, and may vibrate only the top fence 33 when the leaning of the medium M against the top fence 33 is detected. Alternatively, the control unit 38a may make the amount of vibration of the end fence 32 larger than the amount of vibration of the top fence 33 when the leaning of the medium M against the end fence 32 is detected, and may make the amount of vibration of the top fence 33 larger than the amount of vibration of the end fence 32 when the leaning of the medium M against the top fence 33 is detected.

In a configuration in which leaning of the medium M against the side fences