JP2008254354A - Printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer which can assure the print quality or can prevent poor conveyance by assuring the flatness at the print medium conveyance portion of a conveyance belt. <P>SOLUTION: When the absolute value of a lateral gap of a conveyance belt 1 detected by a lateral gap sensor 25 is more than a dead zone threshold Xt, the amount of rotation of a stepping motor corresponding to the lateral gap is set. The lateral gap of the conveyance belt 1 is returned back to proper state by rotating a stepping motor 40 forward and reducing tension of the conveyance belt 1 on the right side in the conveyance direction of a print medium when the lateral gap has a positive value, i.e. when the conveyance belt 1 is shifted to the right side for the conveyance direction of print medium, and by rotating the stepping motor 40 reversely and reducing tension of the conveyance belt 1 on the left side in the conveyance direction of print medium when the lateral gap has a negative value, i.e. when the conveyance belt 1 is shifted to the left side for the conveyance direction of print medium. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

In the present invention, for example, fine particles (droplets) of liquids of a plurality of colors are ejected from nozzles of a liquid ejecting head (
The present invention relates to a printing apparatus that prints predetermined characters and images by forming fine dots on a printing medium.

Such a printing apparatus forms fine dots on a print medium by ejecting liquid droplets from the nozzles of the liquid jet head while relatively moving the print medium and the print head (also referred to as a liquid jet head). Thus, a desired printed matter is created by drawing predetermined characters and images on the print medium. A liquid ejecting head that is mounted on a moving body called a carriage and moves in a direction crossing the conveyance direction of the printing medium is generally called a multi-pass printing apparatus.
On the other hand, a long-line liquid jet head (not necessarily integrated) is arranged in a direction crossing the print medium conveyance direction to enable printing in a so-called one pass. It is called “printing device”.

By the way, in this type of printing apparatus, when a transport belt is used as a print medium transport unit and the print medium is placed on the transport belt and transported, the so-called belt is skewed, that is, the direction intersecting the print medium transport direction. It will shift to. Such a skew of the conveying belt naturally results in a defective conveyance of the print medium, and droplets cannot be ejected to a predetermined position of the print medium, resulting in a decrease in print image quality. Therefore, in the printing apparatus described in Patent Document 1 below, a deviation amount (hereinafter, also referred to as a lateral deviation amount) in a direction intersecting the printing medium conveyance direction of the conveyance belt is detected, and the conveyance belt is determined according to the lateral deviation amount. Is moved by a motor so that one of the driven rollers around which the roller is wound is tilted in the print medium conveyance direction, and the skew of the conveyance belt is suppressed and prevented. Further, in the printing apparatuses described in Patent Document 2 and Patent Document 3 below, the driven roller around which the conveyance belt is wound is moved by an eccentric cam so as to be inclined in a direction intersecting the print medium conveyance direction, and the conveyance belt is inclined. I try to prevent the line from being suppressed.
JP 2004-359379 A JP 2004-359438 A JP 2005-292480 A

However, in each of the printing apparatuses described in each of the above patent documents, since the driven roller around which the conveyor belt is wound is moved so as to be inclined, the skew of the belt is suppressed and prevented. The flatness is impaired, and as a result, the flatness of the print medium is impaired and the print image quality is lowered, or the print medium hits a liquid ejecting head, a roller, or the like, resulting in a conveyance failure. For example, in Patent Document 1 in which the driven roller moves so as to be inclined in the print medium conveyance direction, it seems that the flatness of the conveyance belt is ensured at first glance. Will be damaged.

The present invention has been made paying attention to the problems as described above, and can ensure the printing image quality by ensuring the flatness of the print medium conveyance portion of the conveyance belt, or prevent poor conveyance. An object of the present invention is to provide a possible printing apparatus.

In order to solve the above-described problems, the printing apparatus of the present invention performs printing by ejecting liquid droplets from the nozzles of a liquid ejecting head onto the print medium, transporting the print medium to a print region by placing the print medium on a transport belt. In the printing apparatus, tension adjusting means for adjusting the tension of the transport belt on both sides in a direction intersecting the print medium transport direction, and a shift amount detection for detecting a shift amount of the transport belt in the direction intersecting the print medium transport direction. And on both sides in the direction intersecting the print medium conveyance direction of the conveyance belt by the tension adjusting means according to the deviation amount in the direction intersecting the print medium conveyance direction of the conveyance belt detected by the deviation amount detection means. And a tension control means for controlling the tension.

According to the printing apparatus according to the present invention, the tension on both sides of the conveyance belt in the direction intersecting the print medium conveyance direction is controlled according to the detected deviation amount of the conveyance belt in the direction intersecting the print medium conveyance direction. The amount of deviation of the transport belt in the direction intersecting the print medium transport direction,
That is, the amount of lateral misalignment can be reduced to prevent skewing of the conveyor belt, and since only the tension of the conveyor belt is adjusted, the flatness of the print medium conveyance portion of the conveyor belt is ensured and the printing image quality is improved. It can be ensured or conveyance failure can be prevented.

In the printing apparatus of the present invention, the tension adjusting unit includes a tension roller that applies tension to the conveyor belt, a support mechanism that supports both ends of the tension roller in the rotation axis direction, and a moving mechanism that moves the support mechanism. The moving mechanism includes a motor and an eccentric cam that is rotated by a rotation shaft of the motor and abuts against the support mechanism.

According to the printing apparatus according to the present invention, the eccentric cam is rotated by the motor, and the eccentric cam
By moving the support mechanisms at both ends in the rotational axis direction of the tension roller that applies tension to the transport belt, the tension on both sides of the transport belt in the direction intersecting the print medium transport direction can be adjusted reliably and easily. .
In the printing apparatus according to the aspect of the invention, the tension control unit may detect the tension when a deviation amount in a direction intersecting the printing medium conveyance direction of the conveyance belt detected by the deviation amount detection unit is a predetermined value or more. The adjustment means controls the tension on both sides in the direction intersecting the print medium conveyance direction of the conveyance belt.
According to the printing apparatus according to the present invention, when the amount of deviation of the conveyance belt in the direction intersecting the print medium conveyance direction, that is, the amount of lateral deviation is small, hunting of the tension control of the conveyance belt that prevents the deviation is avoided. be able to.

Next, an embodiment of a printing apparatus according to the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a printing apparatus according to the present embodiment, FIG. 1a is a front view of the printing apparatus according to the present embodiment, and FIG. 1b is a plan view. Reference numeral 1 in the figure denotes an endless conveying belt for conveying a printing medium 2 such as printing paper. The conveyor belt 1 is provided with a driving roller 3 disposed at the left end of the figure.
And a driven roller 4 disposed at the right end portion of the figure and a tension roller 5 disposed below the central portion thereof. The drive roller 3 is rotationally driven in the direction of the arrow in the figure by the conveyance motor 11, and in the state where the print medium 2 is attracted to the conveyance belt 1 charged by the charging roller described later, the print medium 2 is moved from the right side to the left side in the figure. In the direction of the arrow. The driven roller 4 is grounded so as to apply a voltage with the conveying belt 1 being sandwiched between the driven roller 4 and a contact portion of a charging roller described later. The tension roller 5 is disposed inside the transport belt 1 and is urged downward by a tension applying mechanism described later, thereby applying tension to the transport belt 1.

A charging roller 7 as a charging unit is in contact with the conveyor belt 1 so as to face the driven roller 4, and an AC power supply 8 of about 10 to 50 Hz is connected to the charging roller 7. The arrangement of the charging roller 7 corresponds to immediately before the feeding position of the printing medium 2. Charging roller 7
Is charged by charging the surface of the conveyance belt 1 made of a medium / high resistance material, and causes the dielectric polarization to occur in the print medium 2 by the charge, and the charge of the print medium 2 due to the dielectric polarization and the conveyance belt 1 The print medium 2 is attracted to the surface of the transport belt 1 by electrostatic force due to the charge of the dielectric portion on the surface. The charging roller 7 is pressed against the transport belt 1 by a spring (not shown).

A pressure roller 9 is disposed above the driven roller 4. The pressure roller 9 is configured to be pressed downward, that is, to the driven roller 4 side by a pressure solenoid (not shown), and has a function of pressing the print medium 2 against the conveyance belt 1 on the driven roller 4. As described above, when the print medium 2 is mounted on the outer peripheral surface of the charged transport belt 1 and the print medium 2 is pressed against the transport belt 1 by the pressure roller 9, the print medium 2 is placed on the outer peripheral surface of the transport belt 1 by dielectric polarization. Adsorbed.

Reference numeral 6 in FIG. 1 denotes a liquid ejecting head. The liquid ejecting head 6 has yellow (Y),
The four colors of magenta (M), cyan (C), and black (K) are arranged so as to be shifted in the transport direction of the print medium 2. A liquid is supplied to each liquid ejecting head 6 from a liquid tank (not shown) via a liquid supply tube. Each liquid ejecting head 6 is formed with a plurality of nozzles in a direction intersecting with the transport direction of the print medium 2, and a required amount of liquid droplets are simultaneously ejected from these nozzles to a necessary location. 2 forms and outputs a minute dot.
By performing this for each color, it is possible to perform printing by so-called one-pass only by passing the print medium 2 adsorbed on the conveyor belt 1 once. That is, the area where the liquid ejecting head 6 is disposed corresponds to a printing area.

As a method of discharging droplets from each nozzle of the liquid ejecting head, an electrostatic method, a piezo method,
There is a film boiling method. In the electrostatic system, when a drive pulse is applied to the electrostatic gap, which is an actuator, the diaphragm in the cavity is displaced, causing a pressure change in the cavity, and a droplet is ejected from the nozzle by the pressure change. is there. In the piezo method, when a driving pulse is applied to a piezo element that is an actuator, the diaphragm in the cavity is displaced to cause a pressure change in the cavity, and a droplet is ejected from the nozzle by the pressure change. In the film boiling method, there is a small heater in the cavity, the liquid is instantaneously heated to 300 ° C or more, the liquid becomes a film boiling state, bubbles are generated, and droplets are ejected from the nozzle by the pressure change It is. Any droplet discharge method can be applied to the present invention.

A paper discharge sensor 21 for detecting the print medium 2 discharged to the paper discharge unit is disposed downstream of the drive roller 3 in the print medium conveyance direction. Further, a paper feed sensor 22 for detecting the print medium 2 transported to the print area of the liquid ejecting head 6 is disposed upstream of the liquid ejecting head 6 in the print medium transport direction. A linear scale 23 is affixed to the outer peripheral surface of the conveyor belt 1, and a belt encoder 24 that reads the linear scale 23 is disposed.

The print medium 2 before being fed is stored in the paper feed unit 12, and auxiliary rollers 10 d and 10 f that feed the print medium 2 of the paper feed unit 12 and a feed are provided in the print medium conveyance direction ahead of the paper feed unit 12. Rollers 13d and 13f are disposed, and registration rollers 14d and 14f are disposed ahead of the feed rollers 13d and 13f in the print medium conveyance direction. This registration roller 14
d and 14 f are for correcting the posture of the print medium 2 abutted by the feed rollers 13 d and 13 f and adjusting the conveyance timing of the print medium 2. One of the registration rollers 14d and 14f is driven by a stepping motor (not shown), and the other registration roller 14f is a drive-side registration roller 14
Follow d.

A pre-registration sensor 15 is positioned in front of the registration rollers 14d and 14f in the print medium conveyance direction.
A registration sensor 16 is disposed ahead of the registration rollers 14d and 14f in the conveyance direction of the printing medium. Both the pre-registration sensor 15 and the registration sensor 16 are for detecting the print medium 2 and are turned ON when the print medium 2 is conveyed to the sensor position. Further, at the inner circumferential surface of the conveyance belt 1 and the end portion in the direction intersecting the print medium conveyance direction, the conveyance belt 1
A lateral displacement amount detection sensor 25 such as an optical sensor for detecting the position of the end portion in the direction intersecting the print medium conveyance direction and detecting the lateral displacement amount is provided. Lateral displacement detection sensor 2
The lateral deviation amount of the conveyance belt 1 due to 5 is a positive value on the right side and a negative value on the left side with respect to the print medium conveyance direction of FIG.

FIG. 2 shows a right side view of the tension applying mechanism of the tension roller 5 of FIG. 1a. Both ends of the tension roller 5 in the axial direction are supported by a slider 31 that can slide up and down along the frame of the apparatus. A spring 32 is disposed above the slider 31, and an upper end of the spring 32 is a bracket 33. Installed on. The right bracket 33 in the figure is directly fixed to the frame of the apparatus, but the left bracket 33 in the figure is attached to be slidable in the vertical direction along the frame of the apparatus. In the left bracket 33 in this figure, two wall portions 36 projecting sideways are erected up and down in parallel, and between the two wall portions 36, as shown in FIG. A roller bearing 35 at one end of the rotating arm 34
The outer ring is inserted. A central portion of the rotating arm 34 is rotatably supported by a frame of the apparatus via a shaft member 37, and a return spring 38 is attached to the other end portion of the rotating arm 34. The return spring 38 pulls the other end of the rotating arm 34 downward in FIG. 3, and the other end of the rotating arm 34 has an eccentric cam 39.
It is in contact with the outer peripheral surface of. The eccentric cam 39 itself is circular, but the connecting point of the rotating shaft 41 of the step motor 40 connected to the eccentric cam 39 is eccentric from the circular center of the eccentric cam 39.

Therefore, when the step motor 40 is rotated counterclockwise (right rotation in the drawing) from the state of FIG. 3, the other end portion of the rotating arm 34 rises upward in the drawing, and accordingly, one end portion of the rotating arm 34. 2 is lowered and the bracket 33 is lowered downward, the left end portion of the tension roller 5 in FIG. 2 is lowered, the tension on the left side in the conveyance direction of the conveyance belt 1 is increased, and the conveyance belt 1 is relatively conveyed. The right side tension decreases. On the contrary, when the step motor 40 is rotated clockwise from the state of FIG. 3 (left rotation in the drawing), the other end of the rotating arm 34 is lowered downward in the drawing, and accordingly, one end of the rotating arm 34 is moved accordingly. 2 rises upward, and the bracket 33 rises upward, so that the left end of the tension roller 5 in FIG. 2 rises, the tension on the left side of the conveyance belt 1 in the conveyance direction decreases, and the conveyance belt 1 The tension on the right side in the transport direction increases. The inventor
We have intensively studied that it is possible to adjust the lateral displacement of the belt by adjusting the tension at both ends in the width direction of the belt, that is, in the direction crossing the print medium conveyance direction. It has been found that when either one of the tensions at both ends is increased and the other is relatively decreased, the belt moves toward the higher tension. That is, when the conveyance belt 1 is shifted to the right side in the print medium conveyance direction, that is, in the forward direction in FIG.
Is rotated to the left to reduce the tension on the right side of the conveyance belt 1 in the conveyance direction of the print medium. vice versa,
In FIG. 1b, when the conveyance belt 1 is shifted to the left side, that is, in the negative direction, with respect to the printing medium conveyance direction, the step motor 40 is rotated to the right to increase the tension on the left side of the conveyance belt 1 in the printing medium conveyance direction. You can decrease it. Therefore, in this embodiment, the left rotation of the step motor 40 is defined as a positive direction and the right rotation is defined as a negative direction.

Further, a control device for controlling itself is provided in the printing apparatus of the present embodiment. For example, as shown in FIG. 4, the control device prints on a print medium by controlling a printing device, a paper feeding device, and the like based on print data input from a host computer 60 such as a personal computer or a digital camera. The processing is performed. An input interface 61 that receives print data input from the host computer 60 or receives output signals from the belt encoder 24 and the lateral displacement detection sensor 25, and the print data input from the input interface 61. For example, a control unit 62 configured by a microcomputer, a gate roller motor driver 63 for driving and controlling the gate roller motor 17 for driving the registration roller 14d, and a drive roller 13d. A feed roller motor driver 64 for driving and controlling the feed roller motor 51, a head driver 65 for driving and controlling the liquid jet head 6, an electric motor driver 66 for driving and controlling the electric motor 11, and a step motor for driving and controlling the step motor 40. A motor driver 58, a registration roller motor 17 the output signal outside of each driver 63～66,68, the feed roller motor 51, the liquid jet head 6, the electric motor 11,
And an interface 67 that converts the drive signal used by the step motor 40 and outputs the drive signal.

The control unit 62 is a CPU (Central Processing Unit) that executes various processes such as a printing process.
62a and a RAM (temporarily storing print data input via the input interface 61 or various data when executing the print data print processing, or temporarily expanding an application program such as print processing Random Access Memory) 62c and CPU
ROM composed of non-volatile semiconductor memory for storing control program executed in 62a
(Read-Only Memory) 62d is provided. When the control unit 62 obtains print data (image data) from the host computer 60 via the interface 61, the CPU 62a
However, this print data is subjected to a predetermined process to output print data (driving signal selection data SI & SP) indicating from which nozzle a droplet is discharged or how many droplets are discharged. Based on the data and input data from various sensors, each of the drivers 63 to 66
, 68 to output a control signal. When the control signals are output from the drivers 63 to 66, 68, these are converted into drive signals by the interface 67, and the actuators corresponding to the plurality of nozzles of the liquid jet head 6, the registration roller motor 17, the feed roller motor 51, The electric motor 11 and the step motor 40 are operated to execute the feeding and conveyance of the printing medium 2, the attitude control of the printing medium 2, the printing process on the printing medium 2, and the lateral deviation control of the conveying belt 1. The head driver 65 includes a drive waveform signal generation circuit 70 that generates the drive waveform signal WCOM, and an oscillation circuit 71 that oscillates the clock signal SCK.

The liquid jet head 6 selects a nozzle to be ejected based on the drive signal COM obtained by power amplification conversion of the drive waveform signal WCOM through the interface 67 and the print data, and the connection timing to the drive signal COM of an actuator such as a piezo element. A drive signal selection data signal SI & SP for determining the drive signal, a latch signal LAT for connecting the drive signal COM and the actuators of the liquid ejecting heads 2 and 3 based on the drive signal selection data SI & SP after nozzle selection data is input to all nozzles; Channel signal CH, drive signal selection data signal SI & S
A clock signal SCK for transmitting P as a serial signal to the liquid jet heads 2 and 3 and a droplet discharge timing signal for discharging a droplet at the rising edge of a pulse to be described later are input.

Next, of the arithmetic processing performed in the control unit 62 of the control device, the arithmetic processing performed for the lateral displacement control of the conveyor belt 1 will be described with reference to the flowchart of FIG. This calculation process is performed each time a print command is issued. First, in step S1, the electric motor 11 is driven to rotate the transport belt 1.
Next, the process proceeds to step S2, where it is determined whether or not the absolute value of the lateral deviation amount of the conveying belt 1 detected by the lateral deviation amount detecting sensor 25 is equal to or greater than the dead zone threshold value Xt, and the lateral deviation amount of the conveying belt 1 is determined. If the absolute value of is greater than or equal to the dead zone threshold value Xt, the process proceeds to step S3, and if not, the process waits.

In step S3, it is determined whether or not the lateral deviation amount of the conveyor belt 1 detected by the lateral deviation amount detection sensor 25 is a positive value, that is, whether it is on the right side with respect to the printing medium conveyance direction. If the amount is a positive value, the process proceeds to step S4, and if not, the process proceeds to step S5.
In step S4, according to the control map shown in FIG. 6, a step motor rotation amount corresponding to a positive conveyance belt lateral deviation amount is set, and the step motor 40 is driven to rotate in the positive direction by the amount of rotation. After the tension on the right side of the print medium conveyance direction 1 is reduced, the process proceeds to step S6. In this control map, the step motor rotation amount is linearly increased with respect to the increase in the conveyance belt lateral deviation amount.

Further, in step S5, a step motor rotation amount corresponding to the negative conveyance belt lateral deviation amount is set according to the control map shown in FIG. 6, and the step motor 40 is driven to rotate in the negative direction by the amount of rotation. After the tension on the left side of the conveyance belt 1 in the conveyance direction of the printing medium is reduced, the process proceeds to step S6. In this control map, the step motor rotation amount is set to linearly decrease with respect to the decrease in the conveyance belt lateral deviation amount.
In step S6, it is determined whether or not the absolute value of the lateral deviation amount of the conveyance belt 1 detected by the lateral deviation amount detection sensor 25 is equal to or greater than the dead zone threshold value Xt, and the absolute value of the lateral deviation amount of the conveyance belt 1 is the dead zone. If it is equal to or greater than the threshold value Xt, the process returns to the main program, and if not, the process proceeds to step S3.

According to this calculation process, when the absolute value of the lateral deviation amount of the conveyor belt 1 detected by the lateral deviation amount detection sensor 25 is equal to or greater than the dead zone threshold value Xt, the step motor rotation amount corresponding to the lateral deviation amount is set. When the lateral displacement amount is a positive value, that is, when the transport belt 1 is laterally shifted to the right side with respect to the print medium transport direction, the step motor 40 is rotated forward to transport the print medium of the transport belt 1. When the tension on the right side of the direction is decreased and the lateral displacement amount is a negative value, that is, when the transport belt 1 is laterally shifted to the left side with respect to the print medium transport direction, the step motor 40 is rotated negatively and positively. By reducing the tension on the left side of the conveyance belt 1 in the print medium conveyance direction, the lateral deviation of the conveyance belt 1 can be returned to an appropriate state. Further, by providing a dead zone for the lateral deviation control of the conveying belt, it is possible to suppress and prevent control hunting.

As described above, according to the printing apparatus of the present embodiment, printing is performed by placing a printing medium on a conveyance belt and conveying the printing medium to a printing region, and performing printing by discharging droplets from the nozzles of the liquid ejecting head onto the printing medium. In the apparatus, the tension of the conveyance belt can be adjusted on both sides in the direction intersecting the print medium conveyance direction, and the amount of deviation of the conveyance belt in the direction intersecting the print medium conveyance direction is detected. Since the tension on both sides of the direction intersecting the print medium conveyance direction of the conveyance belt is controlled according to the amount of deviation in the direction intersecting the print medium conveyance direction, the direction intersecting the print medium conveyance direction of the conveyance belt The amount of deviation, i.e., the amount of lateral deviation, can be reduced to prevent skewing of the conveyor belt, and since only the tension of the conveyor belt is adjusted, the plane of the print medium conveyor portion of the conveyor belt is adjusted. The by ensuring the printing quality is secured, and to prevent the conveyance failure.

In addition, the eccentric cam is rotated by a motor, and the support mechanism at both ends in the rotational axis direction of the tension roller that applies tension to the conveying belt is moved by the eccentric cam, so that the conveying belt can be surely and easily conveyed in the printing medium conveying direction. The tension on both sides in the direction intersecting with can be adjusted.
Further, when the amount of deviation of the conveyance belt in the direction intersecting the print medium conveyance direction is a predetermined value or more, the conveyance belt is controlled by controlling the tension on both sides in the direction intersecting the print medium conveyance direction. When the deviation amount in the direction intersecting the print medium conveyance direction, that is, the lateral deviation amount is small, it is possible to avoid the hunting of the tension control of the conveyance belt for suppressing it.

In each of the above-described embodiments, only the example in which the printing apparatus of the present invention is applied to a line head type printing apparatus has been described in detail. However, the printing apparatus of the present invention is not limited to a multi-pass printer, and print media can be used. The present invention can be applied to any type of printing apparatus that is transported by a transport belt.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram illustrating an embodiment of a printing apparatus of the present invention, where (a) is a front view and (b) is a plan view. FIG. 2 is a right side view of a tension applying mechanism of the tension roller in FIG. 1. It is explanatory drawing of the tension adjustment mechanism of the tension provision mechanism of FIG. It is a block diagram which shows the control apparatus of the printing apparatus of FIG. It is a flowchart of the arithmetic processing performed by the control part of FIG. 6 is a control map used in the arithmetic processing of FIG.

Explanation of symbols

1 is a conveying belt, 2 is a printing medium, 3 is a driving roller, 4 is a driven roller, 5 is a tension roller, 6 is a liquid ejecting head, 7 is a charging roller, 8 is an AC power supply, 9 is a pressure roller, and 11 is an electric motor. , 12 is a paper feed unit, 13d and 13f are feed rollers, 14d and 14f are registration rollers, 15 is a pre-registration sensor, 16 is a registration sensor, 21 is a paper discharge sensor, 22 is a paper feed sensor, 23 is a linear scale, 24 Is a belt encoder, 25 is a lateral displacement detection sensor, 32 is a spring, 39 is an eccentric cam, and 40 is a step motor.

Claims (3)

In a printing apparatus that performs printing by placing a print medium on a transport belt and transporting the print medium to a print area, and ejecting droplets from a nozzle of a liquid ejecting head onto the print medium, the tension of the transport belt is set as a print medium transport direction. Tension adjusting means for adjusting both sides of the intersecting direction, a deviation amount detecting means for detecting a deviation amount of the conveying belt in a direction intersecting the print medium conveying direction, and a conveyance belt detected by the deviation amount detecting means. And a tension control means for controlling the tension on both sides of the direction of the conveyance belt intersecting the print medium conveyance direction by the tension adjusting means in accordance with the amount of deviation in the direction intersecting the print medium conveyance direction. Printing device to do. The tension adjusting means includes a tension roller that applies tension to the conveyor belt, a support mechanism that supports both ends of the tension roller in the rotation axis direction, and a moving mechanism that moves the supporting mechanism. The printing apparatus according to claim 1, further comprising: a motor; and an eccentric cam that is rotated by a rotation shaft of the motor and abuts against the support mechanism. The tension control unit conveys the print belt on the conveyance belt by the tension adjusting unit when the deviation amount in the direction intersecting the print medium conveyance direction of the conveyance belt detected by the deviation amount detection unit is a predetermined value or more. The printing apparatus according to claim 1, wherein tension on both sides in a direction crossing the direction is controlled.

Images