JP2018192734A - Printer and belt movement amount difference detection method - Google Patents

Abstract

To provide a printer capable of detecting movement amounts generated at one side and the other side of a conveyance belt.SOLUTION: A printer comprises: a conveyance belt 23 conveying a medium in a conveyance direction; a first scale part 75a and a second scale part 75b provided in the conveyance direction; a first detection part 85a detecting a relative movement amount with respect to the first scale part 75a; a second detection part 85b detecting a relative movement amount with respect to the second scale part 75b; a first holding part 80a being constituted integrally with the first detection part 85a, holding one side of the conveyance belt 23 and moving together with the conveyance belt 23; a second holding part 80b being constituted integrally with the second detection part 85b, holding the other side of the conveyance belt 23 and moving together with the conveyance belt 23; and a control part determining whether or not a difference between the first movement amount detected by the first detection part 85a and the second movement amount detected by the second detection part 85b is equal to or more than a reference value.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a printing apparatus and a belt movement amount difference detection method.

In recent years, in printing on fabrics such as cotton, silk, wool, chemical fibers, and mixed spinning, an ink jet printing apparatus that ejects ink toward the surface of the fabric to print a pattern or the like is used. A printing apparatus used in textile printing includes a transport belt that places a medium and transports it in the transport direction in order to handle a stretchable fabric as a medium. In such a printing device,
In order to improve the conveyance accuracy of the conveyance belt, one having a mechanism for detecting the movement amount of the conveyance belt is known. For example, Patent Document 1 discloses an ink jet recording including a movement amount detection unit configured by a scale unit that engages and moves with a conveyor belt and a sensor unit that is fixed to a base and measures the movement amount of the scale unit. An apparatus (printing apparatus) is disclosed.

JP 2013-28143 A

However, there may be a difference in the amount of movement of the transport belt between the one side and the other side in the crossing direction that intersects the transport direction. In the printing apparatus described in Patent Document 1, the movement amount detection unit that detects the movement amount of the conveyance belt is provided only on one of the one side and the other side in the crossing direction. With such a configuration, it is difficult to detect a difference in the amount of movement that has occurred on one side and the other side of the conveyor belt in the crossing direction.

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

Application Example 1 A printing apparatus according to this application example is provided along a printing unit that performs printing on a medium, a conveyance belt that conveys the medium in a conveyance direction by rotating, and the conveyance direction. First and second scale units, a first detection unit that detects a movement amount relative to the first scale unit, and a first detection unit that detects a movement amount relative to the second scale unit. 2 detection units and the first scale unit or the first detection unit are configured to move integrally, and grip one side of the conveyance belt in the crossing direction that intersects the conveyance direction to convey the conveyance belt. The first gripping portion that moves together with the belt, and the second scale portion or the second detection portion are configured to move together, and grips the other side of the transport belt from the center in the intersecting direction. Move with belt A second gripping unit, and a control unit that determines whether or not a difference between the first movement amount detected by the first detection unit and the second movement amount detected by the second detection unit is greater than or equal to a reference value; It is characterized by providing.

According to this application example, the printing apparatus includes a first detection unit that detects a relative movement amount with respect to the first scale unit provided along the conveyance direction, and the first scale unit or the first detection unit. A first gripper that moves integrally and grips one side of the transport belt in the crossing direction that intersects the transporting direction. That is, the first detection unit moves the movement amount on one side of the conveyor belt (
1st movement amount) is detected. Further, the printing apparatus moves integrally with the second detection unit that detects a relative movement amount with respect to the second scale unit provided along the conveyance direction, and the second scale unit or the second detection unit, A second gripping part that grips the other side of the transport belt in the crossing direction intersecting the transporting direction. That is, the second detection unit detects the movement amount (second movement amount) on the other side of the transport belt. The printing apparatus includes a control unit that determines whether the difference between the first movement amount and the second movement amount is equal to or greater than a reference value. As a result, the printing apparatus
It is possible to detect that a difference equal to or greater than the reference value has occurred between the movement amount on one side of the conveyance belt and the movement amount on the other side.

Application Example 2 In the printing apparatus according to the application example described above, the control unit performs the rotational movement of the conveyance belt based on one movement amount of the first movement amount and the second movement amount. It is preferable to control.

According to this application example, the control unit controls the rotational movement of the conveyance belt based on one of the first movement amount and the second movement amount, so that the control of the conveyance belt is complicated. Can be suppressed.

Application Example 3 In the printing apparatus according to the application example, the control unit controls the rotational movement of the transport belt based on an average movement amount obtained by averaging the first movement amount and the second movement amount. It is preferable to do.

According to this application example, the control unit controls the rotational movement of the conveyance belt based on the average movement amount obtained by averaging the first movement amount and the second movement amount. An increase in the difference in the amount of movement can be suppressed.

Application Example 4 In the printing apparatus according to the application example described above, when the control unit determines that the difference between the first movement amount and the second movement amount is greater than or equal to a reference value, the printing unit performs It is preferable to stop printing on the medium.

According to this application example, when the control unit determines that the difference between the first movement amount and the second movement amount is equal to or greater than the reference value, the printing unit stops printing on the medium. It is possible to prevent an image with reduced quality from being printed in advance.

Application Example 5 In the printing apparatus according to the application example described above, the control unit receives input of any print mode from a plurality of print modes having different required image qualities, and changes the image quality of the received print mode. It is preferable to use a corresponding reference value.

According to this application example, the control unit uses the reference value according to the image quality in the print mode, and thus can appropriately print on the medium.

Application Example 6 In the printing apparatus according to the application example described above, it is preferable that the control unit receives an input of the type of image to be printed and uses a reference value according to the received image type.

According to this application example, the control unit uses the reference value according to the type of image to be printed, and thus can appropriately print on the medium.

Application Example 7 In the printing apparatus according to the application example described above, when the number of times the transport belt transports the medium is n, the control unit determines the difference between the first travel distance and the second travel distance. Is calculated and stored as the nth movement amount difference, and the first calculated before the nth movement amount difference is stored.
It is preferable that a difference between the movement amount and the second movement amount is stored as an n−1th movement amount difference.

According to this application example, the printing apparatus stores the difference between the first movement amount and the second movement amount as the n−1th movement amount difference and the nth movement amount difference in time series. It is possible to confirm the change with time of the difference in the movement amount between the first side and the other side.

Application Example 8 In the printing apparatus according to the application example described above, when the control unit determines that the change amount of the n−1 movement amount difference with respect to the nth movement amount difference is greater than or equal to a reference value, a warning is given. It is preferable to perform the operation.

According to this application example, the control unit performs a warning operation when the change amount of the (n−1) th movement amount difference with respect to the nth movement amount difference is equal to or greater than the reference value. By comparing the first movement amount difference and the second movement amount difference, it is possible to predict that the difference between the first movement amount and the second movement amount will increase. Can let you know.

Application Example 9 In the printing apparatus according to the application example described above, the control unit may use a first reference value and a second reference value that is lower than the first reference value as the reference value. The preliminary warning operation is preferably performed when it is determined that the difference between the first movement amount and the second movement amount is less than the first reference value and greater than or equal to the second reference value.

According to this application example, the control unit uses the two reference values, the first reference value and the second reference value, for the first reference value.
It is determined whether or not the difference between the movement amount and the second movement amount is greater than or equal to a reference value. And the control part
When it is determined that the difference between the first movement amount and the second movement amount is less than the first reference value and greater than or equal to the second reference value, a preliminary warning operation is performed. For example, by setting the first reference value to an allowable limit of the difference between the first movement amount and the second movement amount, and setting the second reference value to a value lower than the first reference value, 2
It is possible to inform the user that the difference from the movement amount is approaching the allowable limit.

Application Example 10 The printing apparatus according to the application example includes a drive unit that rotates and moves the conveyance belt, and the drive unit is provided downstream of the printing unit in the conveyance direction.
It is preferable that the gripping unit and the second gripping unit grip the transport belt on the upstream side in the transport direction with respect to the printing unit.

According to this application example, the driving unit of the conveyor belt is provided on the downstream side of the printing unit, and the first and second
The gripping unit grips the transport belt on the upstream side of the printing unit. When the driving unit is driven to rotate in order to move the first and second gripping units gripping the transport belt together with the transport belt in the transport direction, the drive belt rotates in the rotational movement direction of the transport belt, and the downstream side of the transport direction. 1. The conveyor belt on the upstream side in the conveyance direction from the second gripping portion is easily loosened. Drive unit downstream from printing unit, first
By providing the second gripping portion on the upstream side of the printing portion, it is possible to shorten the range in which the conveyance belt is likely to be loosened, so that it is difficult to cause a difference between the first movement amount and the second movement amount. it can.

Application Example 11 A belt movement amount difference detection method for a printing apparatus according to this application example includes a printing unit that performs printing on a medium, a conveyance belt that rotates and conveys the medium in the conveyance direction, and the conveyance direction. Relative to the first scale part and the second scale part, a first detection part for detecting a movement amount relative to the first scale part, and the second scale part. A second detection unit that detects the amount of movement, and the first detection unit or the first detection unit. The second detection unit is configured to move integrally with the first detection unit or the first detection unit. A first gripping part that grips the side and moves together with the transport belt, and is configured to move integrally with the second scale part or the second detection part, and in the cross direction, the other than the center of the transport belt Hold the side A belt movement amount difference detection method for a printing apparatus, comprising: a second gripping portion that moves together with the conveyance belt, wherein the first movement amount detected by the first detection portion and the second detection portion detected by the second detection portion. It is characterized by including the determination process of determining whether the difference with 2 movement amount is more than a reference value.

According to this application example, the belt movement amount difference detection method of the printing apparatus is the first detection by the first detection unit.
A determination step of determining whether or not the difference between the movement amount and the second movement amount detected by the second detection unit is equal to or greater than a reference value is included. The first movement amount is equal to the first scale portion provided along the transport direction and the first
This is the amount of movement relative to the detection unit. Since the first scale unit or the first detection unit moves together with the first gripping unit that grips one side of the transport belt in the crossing direction that intersects the transport direction, the first detection unit is connected to the transport belt. The amount of movement on one side is detected. The second movement amount is
This is a relative movement amount between the second scale unit and the second detection unit provided along the transport direction. Since the second scale unit or the second detection unit moves integrally with the second gripping unit that grips the other side of the center of the transport belt in the intersecting direction, the second detection unit moves by the amount of movement on the other side of the transport belt. Is detected. Therefore, according to the belt movement amount difference detection method, it is possible to detect that a difference of a reference value or more has occurred between the movement amount (conveyance amount) on one side of the conveyance belt and the movement amount (conveyance amount) on the other side. it can.

1 is a schematic diagram illustrating a schematic overall configuration of a printing apparatus according to an embodiment. The top view which shows the principal part of a printing apparatus. The perspective view which shows the structure of a 1st belt movement amount measurement part. Sectional drawing in the AA in FIG. FIG. 3 is an electrical block diagram illustrating an electrical configuration of the printing apparatus. The flowchart figure explaining the belt movement amount difference detection method. A table showing a relationship between a print mode and a reference value. A table showing the relationship between image types and reference values. The flowchart figure explaining the belt movement amount difference detection method which concerns on a modification. The graph which illustrates the moving amount difference change amount of a conveyance belt.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the scale of each layer and each member is different from the actual scale so that each layer and each member can be recognized.
1 to 4, for convenience of explanation, the X axis, the Y axis, and the Z axis are illustrated as three axes that are orthogonal to each other. The end side is defined as “− side”. The direction parallel to the X axis is referred to as “X axis direction”, the direction parallel to the Y axis is referred to as “Y axis direction”, and the direction parallel to the Z axis is referred to as “Z axis direction”.

(Embodiment)
<Schematic configuration of printing device>
FIG. 1 is a schematic diagram illustrating a schematic overall configuration of a printing apparatus according to an embodiment. FIG. 2 is a plan view showing a main part of the printing apparatus. First, a schematic configuration of the printing apparatus 100 according to the present embodiment will be described with reference to FIGS. 1 and 2. In the present embodiment, an ink jet printing apparatus 100 that performs printing on the medium 95 by forming an image or the like on the medium 95 will be described as an example.

As illustrated in FIG. 1, the printing apparatus 100 includes a medium transport unit 20, a medium contact unit 60, and a printing unit 40.
, Drying unit 27, first belt movement amount measurement unit 70a, second belt movement amount measurement unit 70b,
A cleaning unit 50 and the like are provided. And it has the control part 1 which controls each of these parts. Each unit of the printing apparatus 100 is attached to the frame unit 90.

The medium transport unit 20 transports the medium 95 in the transport direction. The medium conveyance unit 20 includes a medium supply unit 10, a conveyance roller 22, a conveyance belt 23, a belt rotation roller 24, a belt driving roller 25, conveyance rollers 26 and 28, and a medium recovery unit 30. First, the conveyance path of the medium 95 from the medium supply unit 10 to the medium recovery unit 30 will be described. In the present embodiment, the direction along the gravity is the Z axis, the direction in which the medium 95 is conveyed in the printing unit 40 is the X axis, and the width direction of the medium 95 that intersects both the Z axis and the X axis is the Y axis. And Further, the positional relationship along the conveyance direction of the medium 95 or the movement direction of the conveyance belt 23 is “upstream side” or “downstream side”.
Also called.

The medium supply unit 10 supplies a medium 95 for forming an image to the printing unit 40 side.
As the medium 95, for example, a cloth such as cotton, wool, or polyester is used. The medium supply unit 10 includes a supply shaft portion 11 and a bearing portion 12. The supply shaft portion 11 is formed in a cylindrical shape or a columnar shape, and is provided to be rotatable in the circumferential direction. A belt-like medium 95 is wound around the supply shaft portion 11 in a roll shape. The supply shaft portion 11 is detachably attached to the bearing portion 12. Thus, the medium 95 that has been wound around the supply shaft portion 11 in advance can be attached to the bearing portion 12 together with the supply shaft portion 11.

The bearing portion 12 rotatably supports both ends of the supply shaft portion 11 in the axial direction. Medium supply unit 1
0 has a rotation drive unit (not shown) for rotating the supply shaft unit 11. The rotation drive unit rotates the supply shaft unit 11 in the direction in which the medium 95 is sent out. The operation of the rotation drive unit is controlled by the control unit 1. The conveyance roller 22 relays the medium 95 from the medium supply unit 10 to the conveyance belt 23.

The conveyance belt 23 is held between at least two rollers that rotate the conveyance belt 23, and conveys the medium 95 in the conveyance direction (+ X axis direction) as the conveyance belt 23 rotates. Specifically, the transport belt 23 is formed in an endless shape by connecting both end portions of a belt-like belt, and is hung between two rollers of a belt rotating roller 24 and a belt driving roller 25. The conveyor belt 23 is held in a state where a predetermined tension is applied so that a portion between the belt rotating roller 24 and the belt driving roller 25 is horizontal. An adhesive layer 29 for adhering the medium 95 is provided on the surface (support surface) 23 a of the transport belt 23. The conveyance belt 23 supports (holds) a medium 95 that is supplied from the conveyance roller 22 and is in close contact with the adhesive layer 29 by a medium contact portion 60 described later. As a result, a stretchable fabric or the like is applied to the medium 9.
5 can be handled.

The belt rotation roller 24 and the belt driving roller 25 are an inner peripheral surface 23 of the transport belt 23.
Support b. In addition, a configuration in which a support portion such as a roller that supports the conveyance belt 23 is provided between the belt rotation roller 24 and the belt driving roller 25 may be employed.

The belt drive roller 25 is a drive unit that rotates and moves the transport belt 23, and includes a motor (not shown) that drives the belt drive roller 25 to rotate. The belt drive roller 25 as a drive unit is provided on the downstream side of the printing unit 40 with respect to the conveyance direction of the medium 95, and the belt rotation roller 24 is provided on the upstream side of the printing unit 40. When the belt driving roller 25 is rotationally driven, the conveyor belt 23 is rotated along with the rotation of the belt driving roller 25.
And the belt rotation roller 24 is rotated by the rotation of the conveyor belt 23. The rotation of the conveyance belt 23 causes the medium 95 supported by the conveyance belt 23 to be conveyed in the conveyance direction (+ X axis direction), and an image is formed on the medium 95 by the printing unit 40 described later.

In the present embodiment, the surface 23a of the conveyor belt 23 faces the printing unit 40 (+ Z axis side).
The medium 95 is supported by the belt rotating roller 24 together with the conveyor belt 23.
From the side to the belt drive roller 25 side. On the side (−Z axis side) where the surface 23 a of the conveyor belt 23 faces the cleaning unit 50, only the conveyor belt 23 moves from the belt driving roller 25 side to the belt rotating roller 24 side. The transport belt 23 has been described as including the adhesive layer 29 that allows the medium 95 to be in close contact therewith, but is not limited thereto. For example, the conveyance belt may be an electrostatic adsorption type belt that adsorbs a medium to the belt with static electricity.

The transport roller 26 peels the medium 95 on which the image is formed from the adhesive layer 29 of the transport belt 23. The transport rollers 26 and 28 relay the medium 95 from the transport belt 23 to the medium recovery unit 30.

The medium collection unit 30 collects the medium 95 conveyed by the medium conveyance unit 20. The medium recovery unit 30 includes a winding shaft portion 31 and a bearing portion 32. The winding shaft portion 31 is formed in a cylindrical shape or a columnar shape, and is provided to be rotatable in the circumferential direction. The winding shaft 31 includes
A belt-like medium 95 is wound up in a roll shape. The winding shaft portion 31 is detachably attached to the bearing portion 32. Thereby, the medium 95 in the state of being wound around the winding shaft portion 31.
Can be removed together with the winding shaft 31.

The bearing portion 32 rotatably supports both ends of the winding shaft portion 31 in the axial direction. The medium recovery unit 30 includes a rotation driving unit (not shown) that drives the winding shaft unit 31 to rotate. The rotation driving unit rotates the winding shaft portion 31 in the direction in which the medium 95 is wound. The operation of the rotation drive unit is controlled by the control unit 1.

Next, each part of the medium contact portion 60, the first belt movement amount measurement unit 70a, the second belt movement amount measurement unit 70b, the printing unit 40, the drying unit 27, and the cleaning unit 50 provided along the medium conveyance unit 20. Will be described.

The medium contact portion 60 is for bringing the medium 95 into close contact with the transport belt 23. Medium adhesion part 6
0 is provided on the upstream side (−X axis side) from the printing unit 40. The medium contact portion 60 includes a pressing roller 61, a pressing roller driving unit 62, and a roller support unit 63. The pressing roller 61 is formed in a cylindrical shape or a columnar shape, and is provided to be rotatable in the circumferential direction.
The pressing roller 61 is disposed so that the axial direction intersects the transport direction so as to rotate in a direction along the transport direction. The roller support portion 63 is provided on the inner peripheral surface 23 b side of the conveyance belt 23 that faces the pressing roller 61 via the conveyance belt 23.

The pressing roller driving unit 62 presses the pressing roller 61 in the conveying direction (+ X axis direction) and the direction opposite to the conveying direction (−X axis direction) while pressing the pressing roller 61 downward in the vertical direction (−Z axis side). The roller 61 is moved. The medium 95 superimposed on the conveyor belt 23 is a pressing roller 61.
And the roller support 63 are pressed against the transport belt 23. Thereby, the medium 95 can be reliably adhered to the adhesive layer 29 provided on the surface 23 a of the transport belt 23, and the occurrence of the floating of the medium 95 on the transport belt 23 can be prevented.

The first belt movement amount measurement unit 70a and the second belt movement amount measurement unit 70b are provided between the medium contact portion 60 and the printing unit 40 in the transport direction. First belt movement amount measuring unit 70a
Is provided on one side (+ Y-axis side) of the center of the conveyor belt 23 in the intersecting direction (Y-axis direction) intersecting the transport direction, and the second belt movement amount measuring unit 70b is in the direction intersecting the transport direction. It is provided on the other side (−Y axis side) from the center of the conveyor belt 23. The configurations of the first belt movement amount measurement unit 70a and the second belt movement amount measurement unit 70b will be described in detail later.

The printing unit 40 is disposed above (+ Z axis side) with respect to the position where the transport belt 23 is disposed, and performs printing on the medium 95 placed on the surface 23 a of the transport belt 23. The printing unit 40 includes a head unit 42, a carriage 43 on which the head unit 42 is mounted, and a carriage 4.
3 for moving the carriage 3 in the width direction (Y-axis direction) of the medium 95 intersecting the transport direction.
5 etc. The head unit 42 according to this embodiment includes four subunits 42a. Further, the subunit 42a includes ink (for example, an ink supplied from an ink supply unit (not shown) to the medium 95 placed on the transport belt 23). A plurality of discharge heads (not shown) for discharging droplets of yellow, cyan, magenta, black, etc.) are provided.

The carriage moving unit 45 is provided above the conveyance belt 23 (+ Z axis side). The carriage moving unit 45 has a pair of guide rails 45a and 45b extending along the Y-axis direction. The guide rails 45a and 45b are bridged between frame portions 90a and 90b that are vertically provided outside the conveyor belt 23. The head unit 42 is supported by the guide rails 45a and 45b so as to be capable of reciprocating along the Y-axis direction together with the carriage 43.

The carriage moving unit 45 includes a moving mechanism and a power source (not shown). As the moving mechanism, for example, a mechanism in which a ball screw and a ball nut are combined, a linear guide mechanism, or the like can be employed. Furthermore, the carriage moving unit 45 includes a motor (not shown) as a power source for moving the carriage 43 along the guide rails 45a and 45b. Various motors such as stepping motors, servo motors, and linear motors can be employed as the motor. When the motor is driven by the control of the control unit 1, the head unit 42 moves along the Y axis direction together with the carriage 43.

The drying unit 27 is provided between the transport roller 26 and the transport roller 28.
The drying unit 27 is for drying the ink ejected on the medium 95. The drying unit 27 includes, for example, an IR heater, and the ink ejected on the medium 95 is driven by driving the IR heater. It can be dried in a short time. Thereby, the belt-shaped medium 95 on which an image or the like is formed can be wound around the winding shaft portion 31.

The cleaning unit 50 is disposed between the belt rotating roller 24 and the belt driving roller 25 in the X-axis direction. The cleaning unit 50 includes a cleaning unit 51, a pressing unit 52, and a moving unit 5.
3. The moving unit 53 integrally moves the cleaning unit 50 along the floor surface 99 and fixes it to a predetermined position.

The pressing part 52 is, for example, an elevating device constituted by an air cylinder 56 and a ball bush 57, and makes the cleaning part 51 provided on the upper part abut on the surface 23a of the conveyor belt 23. The cleaning unit 51 includes a belt rotating roller 24 and a belt driving roller 25.
The surface (support surface) 23a of the conveyor belt 23 that is applied with a predetermined tension between the belt drive roller 25 and moves from the belt drive roller 25 toward the belt rotation roller 24 is washed from below (−Z axis direction). .

The cleaning unit 51 includes a cleaning tank 54, a cleaning roller 58, and a blade 55. The cleaning tank 54 is a tank for storing a cleaning liquid used for cleaning ink and foreign matters attached to the surface 23 a of the conveyor belt 23, and the cleaning roller 58 and the blade 55 are provided inside the cleaning tank 54. As the cleaning liquid, for example, water or a water-soluble solvent (alcohol aqueous solution or the like) can be used, and a surfactant or an antifoaming agent may be added as necessary.

When the cleaning roller 58 rotates, the cleaning liquid is supplied to the surface 23a of the transport belt 23, and the cleaning roller 58 and the transport belt 23 slide. As a result, ink adhering to the conveyor belt 23, fabric fibers as the medium 95, and the like are removed by the cleaning roller 58.

The blade 55 can be formed of a flexible material such as silicon rubber, for example.
The blade 55 is provided downstream of the cleaning roller 58 in the conveyance direction of the conveyance belt 23. When the conveying belt 23 and the blade 55 slide, the conveying belt 23 is moved.
The cleaning liquid remaining on the surface 23a is removed.

FIG. 3 is a perspective view showing the configuration of the first belt movement amount measuring unit. FIG. 4 shows A in FIG.
It is sectional drawing in the -A line. The second belt movement amount measurement unit 70b is configured symmetrically with the first belt movement amount measurement unit 70a with respect to the center of the conveyance belt 23 in the crossing direction that intersects the conveyance direction. Omitted.
First, the configuration of the first belt movement amount measuring unit 70a will be described with reference to FIGS.

The first belt movement amount measurement unit 70 a is provided on the upstream side of the printing unit 40 and is located on the + Y axis side of the conveyance belt 23.
The first belt movement amount measuring unit 70a is a first belt provided along the transport direction (X-axis direction).
The scale unit 75a, the first detection unit 85a that detects the amount of movement relative to the first scale unit 75a, and the first detection unit 85a are configured to move integrally with each other, and intersecting direction (Y-axis direction)
1 has a first gripping portion 80a that grips one side (+ Y-axis side) from the center of the transport belt 23 and moves together with the transport belt 23.

Specifically, the first belt movement amount measuring unit 70 a includes a rectangular parallelepiped base 71 that is long along the conveyance direction (X-axis direction) of the medium 95, a scale attaching unit 73 that is provided above the base 71, and a base. A first grip 8 that moves on a guide rail 72 that is provided on the base 71 and extends in the X-axis direction.
0a, and a return portion 76 that moves the first gripping portion 80a to the upstream side in the transport direction.

The scale attaching part 73 is bridged between pillar parts 73a and 73b provided perpendicularly to both ends in the longitudinal direction (X-axis direction) of the base 71. The scale attaching part 73 in the first belt moving amount measuring part 70a has a protruding part that protrudes like a bowl in the -Y axis direction, and a part of the protruding part 73 overlaps the transport belt 23 in plan view.
The first scale portion 75 a is provided on the lower surface (surface on the −Z axis side) of the protruding portion of the scale pasting portion 73. The first scale portion 75a of the present embodiment uses a magnetic scale in which magnets having different polarities are alternately arranged.

The first gripping unit 80a includes a gripping substrate 81, a guide block 82, a first detection unit 85a, and the like. The gripping substrate 81 has a rectangular plate shape that is long in the width direction (Y-axis direction) of the transport belt 23. An end portion 81c on the −Y-axis side of the holding substrate 81 has a scale pasting portion 73 in plan view.
Substantially coincides with the side wall 73c on the −Y axis side and overlaps with the conveyor belt 23. + Of gripping substrate 81
The end 81d on the Y-axis side protrudes in the + Y-axis direction from the side wall 71d on the + Y-axis side of the base 71 in plan view. A guide block 82 is provided on the bottom surface (the surface on the −Z axis side) of the gripping substrate 81. The guide block 82 is formed with a concave groove that opens on the −Z-axis side, following the shape of the guide rail 72 protruding in a convex shape along the X-axis direction from the base 71. When the guide block 82 and the guide rail 72 are engaged, the first gripping portion 80a is configured to be able to reciprocate along the transport direction (X-axis direction).

An elastic member 83 is provided on the upper surface (the surface on the + Z-axis side) of the gripping substrate 81. The elastic member 83 has a rectangular plate shape shorter than the gripping substrate 81. An end 83 d on the + Y-axis side of the elastic member 83 is joined to the gripping substrate 81 at the approximate center of the gripping substrate 81. The end portion 83c on the −Y axis side of the elastic member 83 is substantially coincident with the end portion 81c on the −Y axis side of the holding substrate 81 in a plan view. The end portion 81 c of the holding substrate 81 and the end portion 83 c of the elastic member 83 have a gap slightly wider than the thickness of the transport belt 23. The first gripping portion 80 a is configured to be able to hold the transport belt 23 between the end portion 81 c of the gripping substrate 81 and the end portion 83 c of the elastic member 83 by the elastic force of the elastic member 83. As a material of the elastic member 83, carbon fiber or the like can be used.

The first gripping portion 80a is an upper surface of the elastic member 83 that does not overlap the transport belt 23 in plan view (+
A ferromagnetic body 84 is provided on the surface on the Z-axis side. As the ferromagnetic material 84, iron, nickel, cobalt, or the like can be used.

In addition, a switching unit 74 that switches the first gripping portion 80a between the gripping state and the non-holding state is provided on the lower surface of the gripping substrate 81 of the first gripping portion 80a and facing the ferromagnetic body 84. . The switching unit 74 includes an electromagnet, and the ferromagnetic body 84 is attracted to the switching unit 74 (electromagnet) by a magnetic force generated when a current flows through the electromagnet. At this time, the elastic member 83
Is elastically deformed toward the holding substrate 81, and the conveying belt 23 is held between the holding substrate 81 and the elastic member 83 by the elastic force. Further, when the current flowing through the electromagnet is interrupted, the first gripping portion 80a changes from the gripping state to the non-grip state.

The first detection unit 85 a is the upper surface of the end 83 c of the elastic member 83 and the first scale unit 75.
It is provided at a position facing a. The first detection unit 85a includes an element (for example, a Hall element or an MR element) that changes the change of the magnetic field into an electric signal, and detects the amount of movement relative to the first scale unit 75a. The first detection unit 85a of the present embodiment includes the first scale unit 7
It is provided on a pedestal for being placed close to 5a. The first detection unit 85a is configured to move integrally with the first gripping unit 80a.

The return unit 76 moves the first gripping unit 80a in a non-gripping state in the direction opposite to the transport direction (−X axis direction). The return unit 76 includes a moving lever 78 and a lever moving unit 77 that reciprocates the moving lever 78 along the transport direction. The lever moving part 77 has a rectangular parallelepiped shape that is long in the transport direction, and is fixed to the side wall 71 d of the base 71 on the + Y axis side. On the upper surface (+ Z-axis side surface) and the lower surface (−Z-axis side surface) of the lever moving portion 77, concave guide grooves extending in the transport direction are formed.

The moving lever 78 includes a pedestal 78a and a pedestal 78 having convex protrusions that follow the shape of the guide groove.
and a long handle portion 78b extending in the vertical direction (+ Z-axis direction). The moving lever 78 is configured to be capable of reciprocating along the X-axis direction by engaging the guide groove of the lever moving portion 77 and the pedestal 78a. The lever moving unit 77 includes a moving mechanism (not shown) that reciprocates the moving lever 78 in the transport direction. For example, an air cylinder can be employed as the moving mechanism. When the moving lever 78 is moved to the upstream side in the conveying direction by the lever moving portion 77, the long handle portion 78b of the moving lever 78 and the gripping substrate 81 of the first gripping portion 80a come into contact with each other, and the first gripping in the non-holding state The part 80a is returned to the upstream side in the direction opposite to the conveyance direction. As a result, the first grip 80 a can be repeatedly moved together with the transport belt 23.

Since the first belt movement amount measurement unit 70a is configured as described above, the first detection unit 85 is configured.
a moves in the transport direction (+ X-axis direction) together with the transport belt 23 gripped by the first gripping portion 80a, and moves on the + Y-axis side (one side) of the transport belt 23 (hereinafter referred to as a first travel distance). Is detected.

The second belt movement amount measurement unit 70 b is provided on the upstream side of the printing unit 40 and is located on the −Y axis side of the conveyance belt 23.
The second belt movement amount measuring unit 70b is a second scale unit 7 provided along the conveyance direction.
5b and a second detection unit 85b for detecting a relative movement amount with respect to the second scale unit 75b,
A second gripping unit 80 configured to move integrally with the second detection unit 85b and grips the other side (−Y-axis side) of the transport belt 23 in the intersecting direction and moves with the transport belt 23.
b.

Since the second belt movement amount measurement unit 70b has the same configuration as that of the first belt movement amount measurement unit 70a in the crossing direction, description of the configuration is omitted.
The second detection unit 85b moves in the transport direction (with the transport belt 23 gripped by the second gripping unit 80b).
+ X-axis direction), and the amount of movement of the conveyor belt 23 on the -Y-axis side (the other side) (hereinafter referred to as the second movement amount) is detected.

The first and second gripping portions 80 a and 80 b of the present embodiment grip the transport belt 23 on the upstream side in the transport direction with respect to the printing unit 40. When the belt driving roller 25 is rotationally driven to move the gripping first and second gripping portions 80a and 80b together with the transport belt 23 in the transport direction, the transport belt 23 has elasticity. In the rotational movement direction, the transport belt 23 at the downstream side in the transport direction from the belt driving roller 25 and at the upstream side in the transport direction from the first and second gripping portions 80a and 80b is easily loosened. By providing the first and second gripping portions 80 a and 80 b on the upstream side of the printing unit 40, the first and second gripping portions 80 a and 80 b are loosened on the transport belt 23 compared to the case where the first and second gripping portions 80 a and 80 b are provided on the downstream side of the printing unit 40. Since the range in which the occurrence of sag is likely to occur can be shortened, the difference between the first movement amount and the second movement amount can be made difficult to occur.

In the present embodiment, the first and second detectors 85a and 85b are the first and second grippers 80a,
Although the first and second scale portions 75a and 75b are moved together with the first and second scale portions 75b and 75b, the first and second scale portions move together with the first and second gripping portions. The second detector may be fixed.
In the present embodiment, the relative movement amount between the first scale unit 75a and the first detection unit 85a,
In addition, a so-called magnetic encoder that obtains the relative movement amount between the second scale unit 75b and the second detection unit 85b by a change in the magnetic field is illustrated, but an optical encoder that obtains the movement amount by an optical change may be used.

<Electrical configuration>
FIG. 5 is an electrical block diagram illustrating an electrical configuration of the printing apparatus. Next, the printing apparatus 100
The electrical configuration will be described with reference to FIG.

The printing apparatus 100 includes an input device 6 to which printing conditions and the like are input, a control unit 1 that controls each unit of the printing apparatus 100, and the like. As the input device 6, a desktop or laptop personal computer (PC) having a display unit 6a, a tablet terminal, a portable terminal, or the like can be used. The input device 6 may be provided separately from the printing device 100.

The control unit 1 includes an interface unit (I / F) 2 and a CPU (Central Processing Unit).
3, the memory | storage part 4, the control circuit 5, etc. are comprised. The interface unit 2 is for transmitting and receiving data between the input unit 6 that handles input signals and images and the control unit 1. The CPU 3 is an arithmetic processing unit for processing input signals from various detector groups 7 including the first and second detection units 85 a and 85 b and controlling the printing operation of the printing apparatus 100. For example, the CPU 3 calculates the first and second movement amounts of the transport belt 23 from the input signals output from the first and second detection units 85 a and 85 b and input to the CPU 3.
The storage unit 4 is a storage medium for securing an area for storing a program of the CPU 3, a work area, and the like, and includes a RAM (Random Access Memory), an EEPROM (Electrically Erasabl).
(e Programmable Read Only Memory).

The control unit 1 controls the drive of the ejection head provided in the head unit 42 by the control signal output from the control circuit 5 to eject ink toward the medium 95. The control unit 1 controls the drive of the motor provided in the carriage moving unit 45 by a control signal output from the control circuit 5 to move the carriage 43 on which the head unit 42 is mounted in the main scanning direction (Y-axis direction). Move back and forth. The control unit 1 controls the drive of the motor provided in the belt driving roller 25 by the control signal output from the control circuit 5 to rotate and move the conveyance belt 23. As a result, the medium 95 placed on the transport belt 23 is moved in the transport direction (+ X-axis direction).

A main scan in which the control unit 1 controls the carriage moving unit 45 and the head unit 42 to move the head unit 42 (carriage 43) while discharging ink from the discharge head;
An image or the like is formed on the medium 95 by a printing operation in which the belt drive roller 25 is controlled to perform sub-scanning in which the medium 95 is conveyed in the conveyance direction.

The control unit 1 controls the current flowing through the electromagnet provided in the switching unit 74 by the control signal output from the control circuit 5 to switch the first and second gripping units 80a and 80b between the gripping state and the non-gripping state. . The control unit 1 controls the lever moving unit 77 according to a control signal output from the control circuit 5.
The moving lever 78 is reciprocated along the transport direction by controlling the moving mechanism. The control unit 1 controls each device (not shown).

<Belt movement amount difference detection method>
FIG. 6 is a flowchart for explaining a belt movement amount difference detection method. FIG. 7 is a table showing the relationship between the print mode and the reference value. FIG. 8 is a table showing the relationship between image types and reference values.
Next, a belt movement amount detection method in the printing operation of the printing apparatus 100 will be described with reference to FIGS.
Will be described with reference to FIG.

Step S1 is a print information receiving step for receiving print data. The control unit 1 receives input of print data or print information for recording an image on the medium 95 from the input device 6, and stores it in the storage unit 4.

Step S2 is a reference value setting step for setting a reference value. The print information received in step S1 includes information on the print mode or image type. Further, for example, a table showing the relationship between the print mode and the reference value as shown in FIG. 7 and a table showing the relationship between the image type and the reference value as shown in FIG. 8 are stored in the storage unit 4 in advance. Has been.

As shown in FIG. 7, a plurality of modes having different required image qualities, such as “super high image quality”, “high image quality”, “fast”, and the like, are prepared as print modes. In each print mode, a reference value serving as a determination reference in a determination process in step S5 described later is set, and two reference values of a first reference value and a second reference value can be used depending on the print mode. Yes. For example, when the print mode is “super high image quality”, the first reference value: “medium” and the second reference value: “low” are used, and when the print mode is “fast”, the first reference value: “medium”. Reference value: Only “high” is used. When the control unit 1 receives an input of any one of a plurality of print modes, the control unit 1 refers to a table stored in the storage unit 4 and sets a reference value according to the image quality of the received print mode. . Note that the first reference value is set to a value that does not satisfy the desired image quality, and the second reference value is set to a value lower than the first reference value. As described above, by using the reference value according to the image quality in the print mode, it is possible to perform printing on the medium 95 suitably.

As shown in FIG. 8, a plurality of types of images expressed as, for example, “line image” and “surface image” are prepared. Here, “line image” means an image mainly composed of text or ruled lines, and “surface image” means an image mainly composed of a photograph or an illustration. For example, when the image type is “line image”, the deviation of the ruled line is easily visually recognized, so the first reference value: “medium” and the second reference value: “low” are used, and the image type is In the case of a “surface image”, the first
A reference value: “high” and a second reference value: “medium” are used. When receiving the input of the type of image to be printed, the control unit 1 refers to the table stored in the storage unit 4 and uses a reference value corresponding to the type of received image. Note that the first reference value is set to a value that does not satisfy the desired image quality, and the second reference value is set to a value lower than the first reference value. As described above, by using the reference value corresponding to the type of image, it is possible to perform printing on the medium 95 suitably.

Step S <b> 3 is a gripping process in which the first gripping portions 80 a and 80 b are gripped by the transport belt 23. The control unit 1 causes a current to flow through the electromagnet of the switching unit 74 to generate a magnetic force in the electromagnet. As a result, the first and second gripping portions 80a and 80b are gripped and grip the transport belt 23.

Step S4 is a sub-scanning step for transporting the transport belt 23 in the transport direction. Control unit 1
Controls the belt driving roller 25 to move the first and second gripping portions 80 a and 80 b in the gripping state together with the transport belt 23. As the transport belt 23 moves, the control unit 1 calculates the first movement amount from the signal output from the first detection unit 85a, and calculates the second movement amount from the signal output from the second detection unit 85b. Then, the rotation operation of the conveyor belt 23 is controlled based on one of the first movement amount and the second movement amount.

In the present embodiment, since the control unit 1 controls the rotation operation of the transport belt 23 based on the first movement amount, the control of the transport belt 23 can be prevented from becoming complicated. Then, in the control unit 1, the first gripping unit 80 a is positioned downstream from the first position (initial position) in the transport direction according to the first movement amount detected by the first detection unit 85 a. The rotation of the conveyor belt 23 is stopped when the second belt moves to the second position. In the first sub-scanning step, the interval between the first position and the second position is a carry amount up to a predetermined position where the printing operation is started. In the second and subsequent sub-scanning steps, the interval between the first position and the second position is the amount of line feed during the printing operation.

In step S5, it is determined whether or not the difference between the first movement amount detected by the first detection unit 85a and the second movement amount detected by the second detection unit 85b is greater than or equal to a reference value (first reference value). It is a judgment process. Since the conveyance belt 23 has elasticity, there is a possibility that a slight shift in the movement amount (conveyance amount) may occur between one side and the other side in the intersecting direction. For this reason, the control unit 1 controls the transport belt 23.
After the movement (conveyance) is stopped, the first movement amount (conveyance belt 2) detected by the first detector 85a is detected.
3) and the second movement amount detected by the second detector 85b (the movement amount on the other side of the conveyor belt 23), and whether the difference is equal to or greater than the first reference value. Judge whether or not. If the difference between the first movement amount and the second movement amount is less than the first reference value (step S5: No), step S5
Proceed to 6. When the difference between the first movement amount and the second movement amount is greater than or equal to the first reference value (step S5: Ye)
s) The control unit 1 determines that the desired image quality cannot be obtained, and stops (ends) printing on the medium 95 by the printing unit 40. As a result, it is possible to prevent an image with reduced image quality from being printed on the medium 95 in advance. The control unit 1 may display on the display unit 6a that printing has been stopped because the first reference value has been exceeded when printing is stopped.

In step S6, it is determined whether or not the difference between the first movement amount detected by the first detection unit 85a and the second movement amount detected by the second detection unit 85b is greater than or equal to a reference value (second reference value). It is a judgment process. If the second reference value is not set, or if the difference between the first movement amount and the second movement amount is less than the second reference value (step S6: No), the process proceeds to step S8. When the difference between the first movement amount and the second movement amount is greater than or equal to the second reference value (step S6: Yes), the process proceeds to step S7.

As described in step S5 and step S6, the control unit 1 detects the movement amount (first movement amount) on the one side of the conveyor belt 23 detected by the first detection unit 85a and the second detection unit 85b. The difference from the movement amount (second movement amount) on the other side of the transport belt 23 is a reference value (first
It is determined whether or not it is equal to or greater than a reference value or a second reference value. As a result, it is possible to detect that a difference equal to or greater than the reference value has occurred between the movement amount on one side of the conveyor belt 23 and the movement amount on the other side.

Step S7 is a preliminary warning process for giving a preliminary warning to the user. When the difference between the first movement amount and the second movement amount is less than the first reference value and greater than or equal to the second reference value, the control unit 1 determines that the image quality may be deteriorated, and performs a preliminary warning operation. I do.
Preliminary warning operation reports that the difference between the first movement amount and the second movement amount is within the allowable range less than the first reference value, but is approaching the limit of the allowable range (first reference value). It is an operation to do. The control unit 1 displays a message such as “The difference in the belt movement amount is increasing. Printing is possible, but maintenance is recommended” on the display unit 6a of the input device 6 via the interface unit 2. To do. Accordingly, it is possible to notify the user that the difference between the first movement amount and the second movement amount (difference in movement amount between one side and the other side of the conveyor belt 23) is approaching the allowable limit. In the present embodiment, the preliminary warning operation is described as displaying a message as a preliminary warning on the display unit 6a of the input device 6. However, the printing apparatus includes a notification unit that performs a preliminary warning operation. The user may be notified of the preliminary warning by emitting sound or light.

Step S <b> 8 is a main scanning process for ejecting ink toward the medium 95. The control unit 1 controls the head unit 42 and the carriage moving unit 45 to move the carriage 43 on which the head unit 42 is mounted from the head unit 42 while moving it in the width direction (Y-axis direction) of the medium 95 intersecting the transport direction. Main scanning is performed to eject ink toward the medium 95.

Step S9 is a non-gripping step for bringing the first and second gripping portions 80a and 80b gripping the conveyor belt 23 into a non-gripping state. The control unit 1 interrupts the current flowing in the electromagnet of the switching unit 74 and demagnetizes the magnetic force of the electromagnet. Thus, the first and second gripping portions 80a and 80b
Is in a non-gripping state.

Step S10 is a return process for returning the return unit 76 to the upstream side in the transport direction. The control unit 1 controls the lever moving unit 77 to move the moving lever 78 waiting at a predetermined position on the downstream side in the transport direction from the first and second gripping portions 80a and 80b to the upstream side in the transport direction. . As a result, the first and second gripping portions 80a and 80b and the moving lever 78 come into contact with each other, and the first and second gripping portions 80a and 80b in the non-gripping state located at the second position are returned to the first position. It is. Accordingly, the first and second gripping portions 80a and 80b in the gripping state can be repeatedly moved from the first position to the second position together with the transport belt 23. Thereafter, the moving lever 78 is moved downstream in the transport direction from the second position, and waits at a predetermined position. For convenience of explanation, the main scanning process in step S8 to the returning process in step S10 have been described in different steps.
And step S8 is performed substantially simultaneously with step S6.

Step S11 is a determination step for determining whether there is print data for the next line. The control unit 1 refers to the print data stored in the storage unit 4 and determines whether there is print data for the next line. If there is print data for the next line (step S11: Yes), the process returns to step S3 and repeats steps S3 to S11. As a result, main scanning and sub-scanning are repeated, and an image or the like is printed on the medium 95. When there is no print data for the next line (step S11: No)
The control unit 1 ends the printing operation of the printing apparatus 100.

In step S4, the control unit 1 has been described as controlling the rotation operation of the conveyor belt 23 based on one of the first movement amount and the second movement amount. ,
The rotation operation of the conveyor belt 23 may be controlled based on an average movement amount obtained by averaging the first movement amount and the second movement amount. Thereby, it can suppress that the difference of the movement amount of the one side of the conveyance belt 23 and the other side becomes large.
In the present embodiment, the flow of performing the returning process for each sub-scanning process and main scanning process is shown. However, after the sub-scanning process and the main scanning process are repeated a plurality of times, the first and second gripping units 80
It is good also as a flow which returns the movement amount which a and 80b moved in multiple times in one return process.

As described above, according to the printing apparatus 100 and the belt movement amount difference detection method according to the present embodiment, the following effects can be obtained.
The printing apparatus 100 measures the amount of movement of one end side of the conveyor belt 23 in the intersecting direction.
A belt movement amount measuring unit 70a and a second belt movement amount measuring unit 70b for measuring the movement amount on the other end side of the conveyor belt 23 are provided. The first belt movement amount measurement unit 70a moves integrally with a first scale unit 75a provided along the conveyance direction and a first detection unit 85a that detects a movement amount relative to the first scale unit 75a. The first gripping portion 8 that grips one side of the transport belt 23
0a. The second belt movement amount measurement unit 70b moves integrally with a second scale unit 75b provided along the conveyance direction and a second detection unit 85b that detects a movement amount relative to the second scale unit 75b. And a second gripping portion 80b for gripping the other side of the transport belt 23. With this configuration, the first detection unit 85a measures the movement amount on one end side of the conveyance belt 23, and the second detection unit 85b measures the movement amount on the other end side of the conveyance belt 23. Further, the printing apparatus 100 determines whether or not the difference between the first movement amount and the second movement amount is greater than or equal to a reference value.
It has. As a result, the printing apparatus 100 can detect that a difference greater than or equal to the reference value has occurred between the movement amount on one side of the conveyance belt 23 and the movement amount on the other side.

Since the control unit 1 of the printing apparatus 100 controls the rotation operation of the transport belt 23 based on the first movement amount, it is possible to suppress the control of the transport belt 23 from becoming complicated.
The control unit 1 of the printing apparatus 100 determines that the desired image quality cannot be obtained when the difference between the first movement amount and the second movement amount is equal to or greater than the first reference value, and the printing unit 40 applies the medium 95 to the medium 95. Stop printing. As a result, it is possible to prevent an image with reduced image quality from being printed on the medium 95 in advance.

When the control unit 1 of the printing apparatus 100 receives an input of any print mode or image type from a plurality of print modes or image types, the control unit 1 refers to the table stored in the storage unit 4 and receives the received print A reference value corresponding to the image quality of the mode or the image type is used. The reference value can use two reference values, the first reference value and the second reference value. The first reference value is set to a value that does not satisfy the desired image quality. The 2 reference value is set to a value lower than the first reference value. Thereby, it is possible to perform printing on the medium 95 suitably.
The first and second gripping units 80 a and 80 b of the printing apparatus 100 grip the transport belt 23 on the upstream side in the transport direction from the printing unit 40. Accordingly, the range in which the conveyor belt 23 is likely to be loosened can be shortened compared to the case where the first and second gripping portions 80a and 80b are provided on the downstream side of the printing unit 40. A difference from the amount of movement can be made difficult to occur.

The belt movement amount difference detection method of the printing apparatus 100 determines whether or not the difference between the first movement amount detected by the first detection unit 85a and the second movement amount detected by the second detection unit 85b is greater than or equal to a reference value. It includes a determination process for determining. The first movement amount is the first scale portion 75a provided along the transport direction.
And the relative amount of movement between the first detector 85a and the first detector 85a. Since the first detection unit 85a moves integrally with the first gripping unit 80a that grips one side from the center of the transport belt 23 in the crossing direction that intersects the transport direction, the first detection unit 85a The amount of movement on one side is detected. The second movement amount is determined by the second scale unit 75b and the second detection unit 8 provided along the transport direction.
It is a relative movement amount with respect to 5b. The second detection unit 85b is configured so that the conveyance belt 23 is in the crossing direction.
The second detector 85 moves together with the second gripper 80b that grips the other side of the center of the second detector 85b.
b detects the amount of movement of the other side of the conveyor belt 23. Therefore, according to the belt movement amount difference detection method, it is detected that a difference greater than a reference value has occurred between the movement amount (conveyance amount) on one side of the conveyance belt 23 and the movement amount (conveyance amount) on the other side. Can do.

Note that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be added to the above-described embodiment. A modification will be described below.

(Modification)
FIG. 9 is a flowchart illustrating a belt movement amount difference detection method according to a modification. FIG. 10 is a graph illustrating the movement amount difference change amount of the conveyance belt. In the belt movement amount difference detection method of the printing apparatus 100 described in this modification, the difference (movement amount difference) between the first movement amount and the second movement amount is stored in time series, and further, the movement amount difference stored before and after is stored. This is different from the embodiment in that a warning operation is performed when the amount of change in the value exceeds a reference value.
Hereinafter, the belt movement amount difference detection method in the printing operation of the printing apparatus 100 according to the modification will be described with reference to FIGS. 9 and 10. Note that the configuration of the printing apparatus 100 is the same as that of the embodiment, and thus the description thereof is omitted. In the flowchart shown in FIG.
101 is the same as step S1 described in the embodiment, steps S102 and S103 are the same as steps S3 and S4 described in the embodiment, and steps S107 to S110 are steps S8 to S10 described in the embodiment. Since it is the same as step S11, its description is omitted.

Step S104 is a movement amount difference change amount storing step of calculating and storing the movement amount difference. When the number of times the transport belt 23 transports the medium 95 (the number of sub-scans) is n, the control unit 1
The difference between the movement amount (the movement amount on one side of the conveyance belt 23) and the second movement amount (the movement amount on the other side of the conveyance belt 23) is calculated and stored in the storage unit 4 as the nth movement amount difference. Thereby, it is possible to confirm a change with time of the difference in the movement amount between the one side and the other side of the conveyor belt 23 (difference in movement amount = second movement amount−first movement amount). Further, the control unit 1 calculates the n−1th movement amount difference, which is the difference between the first movement amount and the second movement amount, which is calculated and stored in the storage unit 4 before the nth movement amount difference is stored. The change amount of the n-th movement amount difference with respect to (hereinafter referred to as movement amount difference change amount) is calculated and stored in the storage unit 4.

For example, the difference between the first movement amount and the second movement amount calculated by the first sub-scan (n = 1) is stored in the storage unit 4 as the first movement amount difference, and the second sub-scan (n = The difference between the first movement amount and the second movement amount calculated in 2) is stored in the storage unit 4 as a second movement amount difference. Then, in the second sub-scan, the control unit 1 calculates a difference of the second movement amount difference with respect to the first movement amount difference (movement amount difference change amount = second movement amount difference−first movement amount difference). In the case of the first sub-scan, the first
The movement amount difference is defined as a movement amount difference change amount. Thereby, the change with time of the movement amount difference change amount can be grasped.

The graph of FIG. 10 shows an example of the movement amount difference change amount calculated when the sub-scan is performed from the first time to the 13th time. The vertical axis of the graph shown in FIG. 10 represents the movement amount difference change amount, and a predetermined reference value is set. The horizontal axis represents the number of sub-scans n. From this graph, in the first to ninth sub-scans, the movement amount on one side and the movement amount on the other side of the conveyor belt 23 are:
It turns out that it is substantially the same with respect to a predetermined movement amount. In the tenth and subsequent sub-scans, the movement amount difference change amount continuously changes to the + reference value side, so the second movement amount (movement amount on the other side of the conveyor belt 23) continues to increase. I understand. This makes it possible to predict that the difference between the first movement amount and the second movement amount (difference in movement amount between one side and the other side of the conveyor belt 23) will increase.

Step S105 is a determination step of determining whether or not the movement amount difference change amount is greater than or equal to a reference value. The control unit 1 refers to the movement amount difference change amount stored in the storage unit 4 and determines whether the movement amount difference change amount is equal to or greater than a predetermined reference value. When the movement amount difference change amount is less than the predetermined reference value (step S105: No), the process proceeds to step S107. When the movement amount difference change amount is equal to or greater than the predetermined reference value (step S105: Yes), the process proceeds to step S106.

Step S106 is a warning process for warning the user. The control unit 1 determines that the image quality is deteriorated and performs a warning operation when the change amount (movement amount difference change amount) of the (n−1) th movement amount difference with respect to the nth movement amount difference is equal to or greater than a reference value. For example, in FIG. 10, the movement amount difference change amount calculated in the thirteenth sub-scan (the change amount of the twelfth movement amount difference with respect to the thirteenth movement amount difference).
Is equal to or greater than the reference value, a warning operation is performed after the thirteenth sub-scanning step. As a warning operation, the control unit 1 displays, for example, a message such as “the difference in the belt movement amount is increasing. Please perform maintenance” on the display unit 6a of the input device 6 via the interface unit 2. . Thereby, it is possible to notify the user of the abnormality of the apparatus in advance. In this modification, the warning operation is described as displaying a message as a preliminary warning on the display unit 6a of the input device 6. However, the printing apparatus includes a notification unit that performs a warning operation. A preliminary warning may be notified to the user by emitting light or the like.

DESCRIPTION OF SYMBOLS 1 ... Control part, 2 ... Interface part, 3 ... CPU, 4 ... Memory | storage part, 5 ... Control circuit, 6 ...
Input device, 6a ... display unit, 7 ... detector group, 10 ... medium supply unit, 20 ... medium transport unit, 24 ...
Belt rotation roller, 25 ... belt drive roller, 30 ... medium recovery unit, 40 ... printing unit, 4
DESCRIPTION OF SYMBOLS 2 ... Head unit, 43 ... Carriage, 45 ... Carriage moving part, 50 ... Cleaning unit, 60 ... Medium contact | adherence part, 70a ... 1st belt movement amount measurement part, 70b ... 2nd belt movement amount measurement part, 75a ... 1st Scale portion, 75b ... second scale portion, 76 ... returning portion, 77 ... lever moving portion, 78 ... moving lever, 80a ... first gripping portion, 80b ... second gripping portion, 81 ... gripping substrate,
83: Elastic member, 84: Ferromagnetic material, 85a: First detection unit, 85b: Second detection unit, 95: Medium, 100: Printing apparatus.

Claims (11)

A printing section for printing on a medium;
A transport belt for transporting the medium in the transport direction by rotating, and
A first scale portion and a second scale portion provided along the transport direction;
A first detection unit that detects a movement amount relative to the first scale unit;
A second detection unit that detects a movement amount relative to the second scale unit;
It is configured to move integrally with the first scale unit or the first detection unit, and grips one side from the center of the transport belt in a crossing direction intersecting the transport direction and moves with the transport belt. 1 gripping part,
A second gripping part configured to move integrally with the second scale part or the second detection part, and grips the other side of the transport belt in the intersecting direction and moves with the transport belt;
A control unit for determining whether a difference between a first movement amount detected by the first detection unit and a second movement amount detected by the second detection unit is a reference value or more;
A printing apparatus comprising: The printing apparatus according to claim 1,
The control unit controls the rotational movement of the transport belt based on one of the first movement amount and the second movement amount. The printing apparatus according to claim 1,
The control unit controls the rotational movement of the conveyance belt based on an average movement amount obtained by averaging the first movement amount and the second movement amount. The printing apparatus according to any one of claims 1 to 3,
The control unit stops printing on the medium by the printing unit when it is determined that a difference between the first movement amount and the second movement amount is a reference value or more. . The printing apparatus according to any one of claims 1 to 4, wherein:
The control unit receives an input of any print mode from a plurality of print modes with different required image quality, and uses a reference value according to the image quality of the received print mode. The printing apparatus according to any one of claims 1 to 4, wherein:
The control unit receives an input of an image type to be printed, and uses a reference value corresponding to the received image type. The printing apparatus according to any one of claims 1 to 6,
When n is the number of times the transport belt transports the medium,
The control unit calculates a difference between the first movement amount and the second movement amount, stores the difference as an nth movement amount difference, and calculates the first calculated before the time when the nth movement amount difference is stored. A printing apparatus, wherein a difference between a movement amount and the second movement amount is stored as an n-1th movement amount difference. The printing apparatus according to claim 7, wherein
The control unit performs a warning operation when determining that the change amount of the (n−1) th movement amount difference with respect to the nth movement amount difference is equal to or greater than a reference value. A printing apparatus according to any one of claims 1 to 8,
The control unit includes a first reference value and a second lower value than the first reference value as the reference value.
A reference value can be used,
A pre-warning operation is performed when it is determined that the difference between the first movement amount and the second movement amount is less than the first reference value and greater than or equal to the second reference value. A printing apparatus according to any one of claims 1 to 9,
A drive unit for rotating and moving the conveyor belt;
The drive unit is provided downstream of the printing unit in the transport direction,
The printing apparatus, wherein the first gripping unit and the second gripping unit grip the transport belt on the upstream side in the transport direction from the printing unit. A printing unit that performs printing on a medium; a conveyance belt that conveys the medium in a conveyance direction by rotating; a first scale unit and a second scale unit that are provided along the conveyance direction; and the first A first detection unit that detects a movement amount relative to the scale unit; a second detection unit that detects a movement amount relative to the second scale unit; and the first scale unit or the first scale unit. A first gripping unit configured to move integrally with the detection unit, gripping one side from the center of the transporting belt in a crossing direction intersecting the transporting direction, and moving with the transporting belt; and the second scale Or a second gripping unit that is configured to move integrally with the second detection unit and that grips the other side of the transport belt in the intersecting direction and moves with the transport belt. Equipment base A preparative movement amount difference detection method,
Including a determination step of determining whether a difference between a first movement amount detected by the first detection unit and a second movement amount detected by the second detection unit is equal to or greater than a reference value. To detect difference in belt movement amount.

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