JP7327004B2 - Image forming apparatus and carriage driving method - Google Patents

Description

The present invention relates to an image forming apparatus and a carriage driving method.

2. Description of the Related Art Conventionally, there is known an image forming apparatus that forms an image by ejecting ink onto a recording medium from nozzles provided in an ink ejection head. This image forming apparatus includes a support member that supports a carriage on which an ink discharge head is mounted so as to be reciprocally movable along a predetermined movement path. There is also a technique for forming an image by ejecting ink onto a recording medium at appropriate timing. Also, a technique is known in which a plurality of carriages are attached to a support member, and ink is ejected from the recording head of each carriage while moving two or more carriages at the same time (for example, Japanese Patent Application Laid-Open No. 2002-200013).

JP 2016-40083 A

However, if the number of carriages to be moved at the same time is increased, the support members may bend depending on the weight of the carriages and the strength of the support members. There is a problem that it comes into contact with Therefore, the conventional technique described above has a problem that an image cannot be properly formed due to the bending of the supporting member.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an image forming apparatus and a carriage driving method capable of appropriately forming an image using a plurality of carriages.

In order to achieve the above object, the invention of the image forming apparatus according to claim 1 is:
a mounting member having a mounting surface on which the recording medium is mounted;
a plurality of carriages each mounted with an image forming operation unit that performs an operation related to image formation on the recording medium on the mounting surface;
a support member that supports the plurality of carriages so that they can reciprocate along a predetermined movement path passing through the mounting surface;
a driving unit that independently moves each of the plurality of carriages along the movement path;
When there are at least two moving carriages among the plurality of carriages, the number of carriages among the plurality of carriages within a predetermined restricted area in the movement path is the number of carriages included in the plurality of carriages. a drive control means for controlling the drive unit so that the number is equal to or less than a predetermined upper limit number that is less than the number of
It is characterized by comprising

The invention according to claim 2 is the image forming apparatus according to claim 1,
position information acquisition means for acquiring position information relating to the position of each of the plurality of carriages on the movement path;
The drive control means is characterized in that, after starting movement of one of the plurality of carriages, the drive control means determines the movement start timing of the next carriage based on the position information relating to the position of the one carriage. there is

The invention according to claim 3 is the image forming apparatus according to claim 1,
The drive control means is characterized in that the movement start timing of the next carriage is determined based on the elapsed time after starting the movement of one of the plurality of carriages.

The invention according to claim 4 is the image forming apparatus according to any one of claims 1 to 3,
The image forming operation unit performs the operation when the carriage on which the image forming operation unit is mounted is within a predetermined image forming area of the movement path,
The restricted area is characterized by including at least part of the image forming area.

The invention according to claim 5 is the image forming apparatus according to claim 4,
The restricted area is set inside both ends of the image forming area.

The invention according to claim 6 is the image forming apparatus according to claim 4 or 5,
The drive control means is characterized by controlling the drive section so that two or more of the plurality of carriages are simultaneously positioned within the image forming area at any timing.

The invention according to claim 7 is the image forming apparatus according to any one of claims 4 to 6,
At least part of the plurality of carriages is mounted with the image forming operation unit having an ink ejection head for ejecting ink onto the recording medium,
The image forming apparatus is characterized by comprising ejection control means for causing the ink ejection head to eject ink at a timing corresponding to the movement of the carriage.

The invention according to claim 8 is the image forming apparatus according to claim 7,
a cleaning unit that cleans the ink ejection head of the carriage at a predetermined cleaning position outside the image forming area;
The drive control means causes at least one of the plurality of carriages, on which the ink discharge head is mounted, to be positioned at the cleaning position when at least one of the plurality of carriages is positioned within the restricted area. It is characterized by controlling the drive unit as follows.

The invention according to claim 9 is the image forming apparatus according to claim 7 or 8,
an ink receiving portion for receiving ink ejected from the ink ejection head of the carriage located outside the image forming area at a predetermined ink receiving position;
The drive control means is arranged such that, when at least one of the plurality of carriages is positioned within the restricted area, at least one of the plurality of carriages on which the ink discharge head is mounted is positioned at the ink receiving position. It is characterized by controlling the drive unit so as to do so.

The invention according to claim 10 is the image forming apparatus according to any one of claims 7 to 9,
At least one of the plurality of carriages is mounted with the image forming operation section having a plurality of first ink ejection heads for ejecting a plurality of basic color inks,
At least one other of the plurality of carriages is mounted with the image forming operation section having a second ink ejection head for ejecting auxiliary color ink other than the plurality of basic colors,
The ejection control means has a first mode for ejecting ink by the first ink ejection head and the second ink ejection head, and a second mode for ejecting ink by the first ink ejection head and the second mode. A second mode in which ink is not ejected by the ink ejection head, and a mode in which ink is ejected by the ink ejection head are selected.

The invention according to claim 11 is the image forming apparatus according to any one of claims 7 to 10,
each of at least two carriages among the plurality of carriages is mounted with the image forming operation unit having the ink ejection head that ejects ink of the same color;
The ejection control means is characterized in that the inks ejected from the ink ejection heads of the at least two carriages are ejected from the ink ejection heads of the at least two carriages onto the recording medium on the mounting surface so as to overlap and land on the recording medium. .

The invention according to claim 12 is the image forming apparatus according to any one of claims 7 to 11,
each of at least two carriages among the plurality of carriages is mounted with the image forming operation unit having the ink ejection head that ejects ink of the same color;
The ejection control means controls ink that has failed to be ejected from the ink ejection heads of some of the at least two carriages onto the recording medium on the mounting surface. It is characterized in that it is complemented by ink ejected from the ink ejection head of any other carriage.

The invention according to claim 13 is the image forming apparatus according to any one of claims 7 to 12,
each of at least two carriages among the plurality of carriages is mounted with the image forming operation unit having the ink ejection head that ejects ink of the same color;
each of the ink ejection heads is provided with a plurality of nozzles for ejecting ink at predetermined intervals in an arrangement direction perpendicular to the movement direction of the carriage along the movement path;
The ink ejection heads of each of the at least two carriages are characterized in that the positions of the nozzles in the arrangement direction are arranged in a positional relationship different from each other.

The invention according to claim 14 is the image forming apparatus according to any one of claims 7 to 13,
The ink ejection head ejects ink that cures when irradiated with ultraviolet rays,
At least part of the plurality of carriages is equipped with the image forming operation section having an ultraviolet irradiation section for irradiating the ink ejected onto the recording medium with ultraviolet rays.

The invention according to claim 15 is the image forming apparatus according to any one of claims 1 to 14,
At least a part of the plurality of carriages is characterized in that the image forming operation section having a functional liquid applying section for applying a predetermined functional liquid to the recording medium is mounted.

The invention according to claim 16 is the image forming apparatus according to any one of claims 1 to 15,
A conveying unit is provided for conveying the recording medium in the conveying direction by moving the mounting surface of the mounting member in the conveying direction that intersects the moving direction of the carriage along the moving path. .

Further, in order to achieve the above object, the invention of the carriage driving method according to claim 17 comprises:
a mounting member having a mounting surface on which a recording medium is mounted; a plurality of carriages each mounted with an image forming operation unit that performs an operation related to forming an image on the recording medium on the mounting surface; a support member that supports a plurality of carriages so as to be able to reciprocate along a predetermined movement path passing through the mounting surface; a drive unit that independently moves each of the plurality of carriages along the movement path; A method for driving a carriage in an image forming apparatus comprising
When there are at least two moving carriages among the plurality of carriages, the number of carriages among the plurality of carriages within a predetermined restricted area in the movement path is the number of carriages included in the plurality of carriages. and a drive control step of controlling the drive unit so that the number is equal to or less than a predetermined upper limit number which is less than the number of .

According to the present invention, there is an effect that an image can be appropriately formed using a plurality of carriages.

It is a figure which shows schematic structure of an inkjet recording device. FIG. 4 is a diagram showing the configuration of a carriage; FIG. 2 is a diagram showing the arrangement of ink ejection heads on a carriage; 1 is a block diagram showing the main functional configuration of an inkjet recording apparatus; FIG. FIG. 4 is a diagram showing the operation of the carriage in the first mode; FIG. FIG. 4 is a diagram for explaining a method of driving a carriage; It is a figure explaining a restricted area|region and a non-restricted area|region in detail. 4 is a flowchart showing a control procedure of image forming processing; FIG. 10 is a diagram showing the arrangement of ink ejection heads on a carriage according to a comparative example; FIG. 10 is a diagram illustrating a printing process in a comparative example and an example of the configuration of the present embodiment; 8A and 8B are diagrams for explaining a carriage driving method according to Modification 1; FIG. 10 is a flowchart showing a control procedure by a control unit for image forming processing according to Modification 2; FIG. 11 is a diagram showing the arrangement of ink ejection heads on a carriage according to Modification 3; FIG. 11 is a diagram illustrating complementary ejection of ink in Modification 3; FIG. 12 is a diagram showing the arrangement of ink ejection heads on a carriage according to Modification 4; FIG. 13 is a diagram showing a configuration of a carriage according to modification 5;

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of an image forming apparatus and a carriage driving method according to the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of an inkjet recording apparatus 1 that is an embodiment of the present invention.
An inkjet recording apparatus 1 (image forming apparatus) includes a conveying section 10, a recording section 20, a control section 30 (see FIG. 4), and the like.

The transport unit 10 includes a drive roller 11, a driven roller 12, a transport belt 13 (placement member), a transport motor 14, and the like.
The drive roller 11 rotates about its rotation axis by being driven by the transport motor 14 . The conveying belt 13 is a ring-shaped belt whose inner side is supported by the driving roller 11 and the driven roller 12, and circulates as the driving roller 11 rotates. The driven roller 12 rotates about a rotation axis parallel to the rotation axis of the driving roller 11 as the conveying belt 13 rotates. The outer peripheral surface of the transport belt 13 constitutes a mounting surface 13a on which the recording medium P is mounted. The conveying belt 13 is made of a material that bends flexibly at the contact surface with the driving roller 11 and the driven roller 12 and reliably supports the recording medium P. For example, a belt made of resin such as rubber, A steel belt or the like can be used. The conveying belt 13 has a material and/or structure that attracts the recording medium P, so that the recording medium P can be more stably mounted on the mounting surface 13a.

The transport motor 14 rotates the driving roller 11 at a rotational speed according to the control signal from the control section 30 . The conveying unit 10 conveys the recording medium P by rotating the conveying belt 13 at a speed corresponding to the rotation speed of the driving roller 11 while the recording medium P is placed on the mounting surface 13 a of the conveying belt 13 . A conveying operation of conveying in the moving direction (conveying direction, sub-scanning direction) of the conveying belt 13 is performed. In other words, the transport unit 10 transports the recording medium P in the transport direction by moving the mounting surface 13a of the transport belt 13 in the transport direction. The conveying unit 10 also includes a rotary encoder (not shown) that detects the rotation angle of the driving roller 11 and transmits the detection result to the control unit 30 .

FIG. 1 depicts an example in which the recording medium P is a sheet of paper. However, the recording medium P is not limited to a sheet of paper, such as roll paper that is unwound (unwound) from a roll (recording medium unwinding unit) on which the recording medium P is wound and is supplied onto the conveying belt 13 . may be In addition to paper, the recording medium P may be made of various materials such as cloth and sheet-like resin, which are capable of fixing ink ejected onto the surface thereof.
Although the size of the recording medium P is not particularly limited, for example, a large medium having a width of about 2 m in the main scanning direction perpendicular to the sub-scanning direction can also be used. Therefore, the conveying section 10 of this embodiment is configured to be capable of conveying a large recording medium P having a width of about 2 m in the main scanning direction. Note that the transport unit 10 may transport a recording medium P having a width of less than 2 m in the main scanning direction. Further, the conveying unit 10 may be configured to be capable of conveying a recording medium P having a width of more than 2 m (for example, about 4 m) in the main scanning direction. The maximum width in the direction may be less than 2 m.

The recording unit 20 includes a first carriage 21A and a second carriage 21B (hereinafter referred to as the carriage 21 when referring to any one of them) each having an ink ejection head 213 for ejecting ink. , a main scanning rail 22 to which a first carriage 21A and a second carriage 21B are attached, a cleaning unit 23 (cleaning section), a capping unit 24 (ink receiving section), and the like.
While moving the first carriage 21A and the second carriage 21B along the main scanning rail 22, the recording unit 20 ejects ink from the ink ejection heads 213 of each carriage 21 onto the recording medium P on the placement surface 13a. main scanning operation is performed.
In addition, the inkjet recording apparatus 1 alternately performs the main scanning operation and the sub-scanning operation in which the conveying unit 10 conveys the recording medium P by a predetermined distance in the sub-scanning direction, thereby forming an image on the recording medium P. to form

The main scanning rail 22 has a support member 221 extending in the main scanning direction.
The support member 221 supports the first carriage 21A and the second carriage 21B so as to be able to reciprocate along a one-dimensional movement path passing over the placement surface 13a and parallel to the main scanning direction. Although the support member 221 of this embodiment is a prismatic member, it is not limited to this shape. A pair of linear guides 222 , a linear motor magnet 223 , and a linear scale 224 are provided on the mounting surface of the support member 221 to which the carriage 21 is mounted (side surface facing the transport direction in FIG. 1).

The linear guide 222 is a rail for guiding the carriage 21 in the main scanning direction. The linear guide 222 has grooves extending in the main scanning direction. The carriage 21 can slide along the linear guide 222 in a state in which a mounting member (not shown) provided on the carriage 21 is fitted in the groove.

The linear motor magnet 223 is a line-shaped magnet for moving each carriage 21 by the operation of the linear motor 215 (driving unit) (see FIG. 2) mounted on each carriage 21, and is attached to the stator of the linear motor. Equivalent to. Specifically, the linear motor magnet 223 is a magnet array in which N poles and S poles are repeatedly arranged in the main scanning direction. In this embodiment, the magnetic poles at each position of the linear motor magnet 223 are fixed, and the carriage 21 moves as the magnetic poles of the carriage 21 on the linear motor 215 side change.

The linear scale 224 is a member extending in the main scanning direction, and has a scale engraved on its surface that can be read by a linear encoder 216 (see FIG. 2) mounted on each carriage 21 .

At both ends of the support member 221 in the main scanning direction, struts 225 are provided to support the support member 221 from below in the vertical direction. A member for supporting the support member 221 is not provided in the region between the pair of pillars 225, and the support member 221 supports the carriage 21 with its rigidity.

FIG. 2 is a diagram showing the configuration of the carriage 21. As shown in FIG.
The carriage 21 includes a housing 211, an image forming operation section 212 housed inside the housing 211, a head driving board 214, a linear motor 215 (driving section), a linear encoder 216, and the like. In FIG. 2 , for convenience of explanation, a part of the housing 211 is drawn transparently to show the internal structure of the housing 211 .

The image forming operation unit 212 has eight ink ejection heads 213, and performs operations related to image formation on the recording medium P on the placement surface 13a of the conveying belt 13 (here, ink ejection by the ink ejection heads 213). discharge operation). The image forming operation section 212 performs the above operation when the carriage 21 on which the image forming operation section 212 is mounted is within the predetermined image forming area Rp in the movement path. This image forming area Rp is set in an area facing the mounting surface 13a or in an area excluding the vicinities of both ends of the area.

Each of the eight ink ejection heads 213 has a nozzle surface formed with a plurality of nozzles for ejecting ink, and the nozzle surface is exposed through an opening provided in the bottom surface 211a of the housing 211. It is fixed to the housing 211 with . Each ink ejection head 213 is attached at a position where the distance between the nozzle surface during the main scanning operation and the placement surface 13a of the transport belt 13 is a predetermined distance (for example, about 2 mm).

FIG. 3 is a diagram showing the arrangement of the ink ejection heads 213 on the carriage 21. As shown in FIG. FIG. 3 is a diagram showing the bottom surfaces 211a of the first carriage 21A and the second carriage 21B viewed from the side of the carrying surface 13a of the transport belt 13. FIG.

Two ink ejection heads 213Y, 213M, 213C, and 213K that respectively eject Y (yellow), M (magenta), C (cyan), and K (black) inks are mounted on the first carriage 21A. there is Y, M, and C are three primary colors used for expressing colors by subtractive color mixture, and K is black, which is actually difficult to obtain only by superimposing the three primary colors. These four colors are called basic colors (process colors), and are a combination of basic colors used for image recording by various image forming apparatuses including an inkjet recording apparatus. The ink ejection heads 213Y, 213M, 213C, and 213K correspond to the first ink ejection heads.

Two ink discharge heads 213LM, 213LC, 213O, and 213G for discharging LM (light magenta), LC (light cyan), O (orange), and G (gray) inks, respectively, are mounted on the second carriage 21B. ing. Each of LM, LC, O, and G is an auxiliary color having a hue different from that of the basic color. Auxiliary colors are mixed with at least one of Y, M, and C to express a color different from the combination of basic colors. The ink ejection heads 213LM, 213LC, 213O, and 213G correspond to the second ink ejection heads.

Each ink ejection head 213 is provided with two rows of nozzles. Each nozzle row is composed of a plurality of nozzles N that are one-dimensionally arranged at regular intervals in the sub-scanning direction (arrangement direction). The two nozzle rows have a positional relationship in which the positions of the nozzles N in the sub-scanning direction are shifted by 1/2 of the arrangement pitch of the nozzles N from each other. However, the number of nozzle rows is not limited to two, and may be one or three or more.
The mechanism for ejecting ink from each nozzle N of the ink ejection head 213 is not particularly limited. A mechanism is used in which the ink is ejected from the nozzle N by deforming the pressure chamber to generate pressure fluctuations in the ink in the pressure chamber.

The two ink ejection heads 213 of the same color are shifted in position in the main scanning direction so that the arrangement range of the nozzles N in the sub scanning direction is continuous over the width W in FIG. are arranged in an end-to-end positional relationship. The eight ink ejection heads 213 mounted on one ink ejection head 213 are arranged in a houndstooth pattern.

Returning to FIG. 2, the head drive board 214 is a board on which a head control circuit is mounted for outputting a drive signal for driving the piezoelectric element to the ink discharge head 213 based on the image data of the recorded image. The head drive substrate 214 is electrically connected to the ink ejection heads 213 via wiring (not shown), and the ink ejection heads 213 are controlled by the head control circuit at appropriate timing according to the position of the carriage 21 in the main scanning operation. output a drive signal to FIG. 2 shows an example in which one head drive substrate 214 is provided for eight ink ejection heads 213, but the present invention is not limited to this. A head driving substrate 214 may be provided for each head 213 .

The linear motor 215 is an electromagnetic motor that serves as a drive source for moving the carriage 21 along the linear guide 222 and the linear motor magnet 223 . Although the specific configuration of the linear motor 215 is not particularly limited, for example, a configuration in which the magnetic pole of the electromagnetic coil is changed by controlling the current to the electromagnetic coil can be used. Thus, in this embodiment, the magnetic pole of the linear motor magnet 223 is fixed, and the carriage 21 is driven by changing the magnetic pole of the carriage 21 on the linear motor 215 side. Thereby, each carriage 21 can be moved independently. That is, it is possible to independently determine the timing of starting and ending movement of each carriage 21, and to drive each carriage so that at least two or more carriages are moving at least part of the timing. It is possible. A driving unit is configured by a plurality of linear motors 215 of a plurality of (here, two) carriages 21 .

The linear encoder 216 reads the scale of the linear scale 224 when the carriage 21 moves, and outputs a signal indicating the position of the carriage 21 to the control unit 30 according to the reading result. As the linear encoder 216, for example, a type that reads the scale by an optical sensor is used, but it is not limited to this. The position of the carriage 21 can be the position of the representative point of the carriage 21 . This representative point can be any position on the carriage 21 as long as it is common to each carriage 21, and can be the position where the optical sensor of the linear encoder 216 is provided, for example.

Returning to FIG. 1, the cleaning unit 23 is provided at a position facing the nozzle surface of the ink ejection head 213 when the carriage 21 moves to a predetermined cleaning position. The cleaning unit 23 performs a cleaning operation of cleaning the nozzle surface of the carriage 21 that has moved to the cleaning position. The cleaning position is outside the image forming area Rp and is set at a position near one end (the right side in FIG. 1) of the movement path of the carriage 21 .

The cleaning unit 23 wipes and removes ink and other contaminants adhering to the nozzle surface by moving the wiping member (not shown) along the nozzle surface while the wiping member is in contact with the nozzle surface. . As the wiping member, a blade made of an elastically deformable member such as urethane or rubber can be used. However, the material of the wiping member is not limited to this, and a porous member (porous) made of resin such as polyolefin, various kinds of cloth, sponge, or the like may be used. FIG. 1 shows an example in which one cleaning unit 23 is provided for each of the first carriage 21A and the second carriage 21B. You may

The capping unit 24 is provided at a position facing the nozzle surface of the ink ejection head 213 when the carriage 21 moves to a predetermined ink receiving position. The capping unit 24 receives and stores ink ejected from the nozzles N of the ink ejection head 213 by an ink ejection operation (flushing). In addition, the capping unit 24 covers the nozzle surface of the ink ejection head 213 to prevent the nozzle surface from drying after the discharging operation is completed. By performing the spitting-out operation, it is possible to discharge foreign substances and air bubbles in the nozzles N to the outside together with the ink. In addition to the normal ink ejection operation from the nozzle N, the ejection operation may be an operation (pressurization purge) of forcibly ejecting the ink from the nozzle N by applying pressure to the ink in the nozzle N from the outside. can. The ink receiving position is set outside the image forming area Rp and near the end on the other side (the left side in FIG. 1) of the movement path of the carriage 21 .
FIG. 1 shows an example in which one capping unit 24 is provided for each of the first carriage 21A and the second carriage 21B. You may

FIG. 4 is a block diagram showing the main functional configuration of the inkjet recording apparatus 1. As shown in FIG.
The inkjet recording apparatus 1 includes a transport motor 14 provided in a transport section 10, an ink ejection head 213 provided in a carriage 21, a head drive substrate 214, a linear motor 215 and a linear encoder 216, a cleaning unit 23, and a control section. 30 (drive control means, position information acquisition means, discharge control means), an operation display section 41, a communication section 42, a bus 43, and the like. Below, explanation is omitted about the already explained component.

The control unit 30 has a CPU 31 (Central Processing Unit), a RAM 32 (Random Access Memory), a ROM 33 (Read Only Memory), and a storage unit 34 .

The CPU 31 reads various control programs and setting data stored in the ROM 33, stores them in the RAM 32, and executes the programs to perform various arithmetic processing.

RAM 32 provides working memory space for CPU 31 and stores temporary data. RAM 32 may include non-volatile memory.

The ROM 33 stores programs for various controls executed by the CPU 31, setting data, and the like. A rewritable nonvolatile memory such as an EEPROM (Electrically Erasable Programmable Read Only Memory) or a flash memory may be used instead of the ROM 33 .

The storage unit 34 stores a print job (image forming command) input from an external device via the communication unit 42 and image data related to the print job. As the storage unit 34, for example, a HDD (Hard Disk Drive) is used, and a DRAM (Dynamic Random Access Memory) or the like may be used together.

The control unit 30 configured as described above centrally controls the overall operation of the inkjet recording apparatus 1 by the CPU 31 executing a predetermined process according to a program.
For example, the control unit 30 sends a control signal to the transport motor 14 at an appropriate timing to operate the transport motor 14 to rotate the drive roller 11, and the transport unit 10 moves the recording medium P at a predetermined speed for a predetermined distance. be transported.
Further, the control unit 30 as position information acquisition means acquires position information regarding the position of each carriage 21 on the movement path based on the signal received from the linear encoder 216 .
Further, the control unit 30 as ejection control means sends image data and control signals to the head drive substrate 214 to drive the ink ejection heads 213 from the head drive substrate 214 at appropriate timing according to the position of the carriage 21 . A signal is output and ink is ejected from the nozzle N of the ink ejection head 213 .
Further, the control unit 30 as drive control means sends a control signal to the linear motor 215 to operate it, and starts the movement operation of each carriage 21 in the main scanning direction at an appropriate timing.
Further, the control section 30 sends a control signal to the cleaning unit 23 at the timing when the carriage 21 moves to the cleaning position, and causes the cleaning unit 23 to perform the cleaning operation.

The operation display unit 41 includes a display device such as a liquid crystal display or an organic EL display, and an input device such as an operation key and a touch panel arranged over the screen of the display device. The operation display unit 41 displays various types of information on the display device, converts the user's input operation to the input device into an operation signal, and outputs the operation signal to the control unit 30 .

The communication unit 42 transmits and receives data to and from an external device according to a predetermined communication standard. The communication unit 42 includes a connection terminal related to the communication standard to be used, driver hardware (network card) related to communication connection, and the like.

A bus 43 is a path for transmitting and receiving signals between the control unit 30 and other components.

Next, an image forming operation by the inkjet recording apparatus 1 will be described.
As described above, the inkjet recording apparatus 1 performs a main scanning operation in which the recording unit 20 moves the carriage 21 along the main scanning rail 22 and ejects ink from the ink ejection head 213 onto the recording medium P, and the conveying unit 10 performs recording. An image is formed on the recording medium P by alternately performing a sub-scanning operation in which the medium P is conveyed in the sub-scanning direction by a predetermined distance.

Further, the control unit 30 controls the ink discharge head in one mode selected from a first mode in which an image is formed by combining basic colors and auxiliary colors, and a second mode in which an image is formed only by basic colors. 213 ejects ink to form an image on the recording medium P; Therefore, in the first mode, the first carriage 21A and the second carriage 21B are used for image formation, and in the second mode, only the first carriage 21A is used for image formation. Selection of the mode is performed, for example, based on an input operation on the operation display unit 41 by the user. The operation of the first mode using the two carriages 21 will be described in detail below.

FIG. 5 shows the operation of the carriage 21 in the first mode.
As shown in FIG. 5, in the first mode, while the first carriage 21A is moving along the support member 221 of the main scanning rail 22 to perform the main scanning operation, the second carriage 21B is moving. Movement is started. Therefore, the first carriage 21A and the second carriage 21B move simultaneously in the main scanning direction during a part of the image forming operation. In other words, the controller 30 controls the linear motor 215 of each carriage 21 so that at least two carriages are moving during a part of the image forming operation.

However, as described above, the region between the pair of struts 225 is not provided with a member that supports the support member 221, and the support member 221 receives an excessive load in the vertical direction at a position away from the struts 225. and deflection occurs.
In recent years, the number of ink ejection heads 213 mounted on the carriage 21 has increased and the weight of the carriage 21 has tended to increase due to the demand for higher throughput image formation and higher definition of color tone expression. In particular, in the inkjet recording apparatus 1 for textiles and home fabrics, there is a demand to lengthen the support member 221 of the main scanning rail 22 in order to expand the image forming width. The weight increase of the carriage 21 and the lengthening of the support member 221 are both likely to cause the support member 221 to bend.

In contrast, in this embodiment, in order to suppress the bending of the support member 221, the carriages 21 are arranged so that the number of the carriages 21 within the predetermined restricted area R1 in the movement path of the carriage 21 is equal to or less than the predetermined upper limit number. is driven. The above upper limit number is less than the number of carriages 21 that the inkjet recording apparatus 1 has. Since the number of carriages 21 is two in this embodiment, the upper limit number is one. That is, the carriage 21 is driven so that the number of carriages in the restricted area R1 is one or less at any timing.

Here, the restricted area R1 is a weight restricted area in which the weight applied to the support member 221 is restricted. The restricted area R1 is an area where the support member 221 bends and the image quality of the recorded image falls below a predetermined standard when the number of carriages 21 equal to or greater than the upper limit is positioned within the restricted area R1. This deterioration in image quality is caused by the fact that the distance between the nozzle surface of the ink ejection head 213 and the recording medium P becomes smaller due to the bending of the support member 221, and the landing position of the ink ejected from the nozzle N deviates from the desired position. occur. Further, the nozzle surface may come into contact with the recording medium P depending on the bending amount of the support member 221 . The allowable value of the bending amount of the support member 221 is, for example, about ±100 μm.
In this embodiment, by keeping the number of carriages 21 positioned in the restricted area R1 below the upper limit, the bending of the support member 221 is effectively suppressed.

The restricted area R1 corresponds to part of the image forming area Rp. In this embodiment, the restricted area R1 is set inside both ends of the image forming area Rp. Therefore, even if one carriage 21 is within the restricted area R1, the other carriage 21 can be positioned outside the restricted area R1 in the image forming area Rp. At this timing, ink can be ejected from the ink ejection heads 213 of the two carriages 21 to the same recording medium P in parallel. Hereinafter, a period in which the ink ejection heads 213 of the two carriages 21 eject ink in parallel is also referred to as a "parallel ejection period". The longer the parallel ejection period, the shorter the image forming time. For this reason, the control unit 30 controls the linear movement of each carriage 21 so that the two carriages 21 are simultaneously positioned within the image forming region Rp at some timing while preventing the two carriages 21 from entering the restricted region R1. Controls motor 215 .

Below, portions of the movement path of the carriage 21 outside the restricted area R1 are referred to as non-restricted areas R2 and R3. The non-restricted area R2 is an area on one end side of the restricted area R1 in the movement route, and the non-restricted area R3 is an area on the other end side of the restricted area R1 in the movement path. The non-restricted areas R2 and R3 are areas where the support member 221 is fixed to the structure of the inkjet recording apparatus 1 (here, the support 225) and areas near the fixed area. This is an area where the support member 221 does not bend to an extent that affects the image quality even if the number of carriages 21 is positioned.

Next, a method for driving the two carriages 21 will be described in detail.
6A and 6B are diagrams for explaining a method of driving the carriage 21. FIG.
FIG. 6 shows temporal changes in the positions of the first carriage 21A and the second carriage 21B. Hereinafter, for the sake of convenience, of the movement paths of the carriage 21, the route from the left end to the right end in FIG.
The vertical axis in FIG. 6 represents the position in the main scanning direction when the left end in FIG. 1 of the moving path of the carriage 21 is set as the origin. The position pp1 is the left end position of the image forming region Rp, and the position pp2 is the right end position of the image forming region Rp. In FIG. 6, the image forming region Rp is hatched. The position pr1 is the position of the boundary between the restricted area R1 and the non-restricted area R2, and the position pr2 is the position of the boundary between the restricted area R1 and the non-restricted area R3.

FIG. 7 is a diagram illustrating in detail the restricted region R1 and non-restricted regions R2 and R3.
The thick lines in FIG. 7 indicate the restricted region R1 or non-restricted regions R2, R3. Of the circles at both ends of each line, a black circle indicates that the area includes the position of the edge, and a white circle indicates that the area does not include the position of the edge. Therefore, the restriction region R1 does not include the positions pr1 and pr2, but includes the regions inside the positions pr1 and pr2. Also, the non-restricted region R2 includes the position pr1 and a region outside the position pr1. Also, the non-restricted region R3 includes the position pr2 and a region outside the position pr2. A movement path Rmv of the carriage 21 consists of a restricted area R1 and non-restricted areas R2 and R3.

As shown in FIG. 6, when the image forming operation is started (the origin of the time axis), the first carriage 21A and the second carriage 21B are positioned at standby positions in the non-restricted area R2. Here, the standby position of the non-restricted area R2 is the above-described ink receiving position, that is, the position facing the capping unit 24. As shown in FIG.

When image formation is started, the movement of the first carriage 21A is first started at timing ta1. After starting to move, the first carriage 21A accelerates at a predetermined acceleration and reaches a predetermined speed before reaching the position pp1. After that, the first carriage 21A ejects ink from the ink ejection head 213 while moving at a constant speed within the image forming area Rp to perform outward printing.

Next, at timing tb1 when the first carriage 21A reaches the position pa, movement of the second carriage 21B is started. After starting to move, the second carriage 21B accelerates at a predetermined acceleration and reaches a predetermined speed before reaching the position pp1. After that, the second carriage 21B ejects ink from the ink ejection head 213 while moving at a constant speed within the image forming region Rp to perform outward printing.
The speed of the first carriage 21A and the speed of the second carriage 21B during outward printing are equal to each other.

At the timing tx1 when the second carriage 21B reaches the position pr1, the preceding first carriage 21A reaches the position pr2. In other words, the movement start timing tb1 of the second carriage 21B is determined such that the first carriage 21A reaches the position pr2 when the second carriage 21B reaches the position pr1. In other words, the first carriage 21A reaches the position pr2 when the time required for the second carriage 21B to reach the position pr1 after starting to move is tm1 (=tx1-tb1). The position of the first carriage 21A at a timing earlier than the timing by time tm1 is defined as the position pa.
Therefore, only the first carriage 21A is positioned in the restricted area R1 before the timing tx1, and only the second carriage 21B is positioned in the restricted area R1 after the timing tx1. Therefore, only one carriage 21, which is the upper limit number, is positioned in the restricted area R1 at an arbitrary timing in forward printing.

After completing forward printing, the first carriage 21A and the second carriage 21B stop at the waiting position in the non-restricted area R3. Here, the standby position in the non-restricted area R3 is the above-described cleaning position, that is, the position facing the cleaning unit 23 .

When each carriage 21 stops, the sub-scanning operation by the transport section 10 is performed. In the sub-scanning operation, the recording medium P is conveyed by a predetermined distance in the sub-scanning direction. In the case of the one-pass method in which image formation is completed by ink ejection in one main scanning operation for each position on the recording medium P, the predetermined distance is the width W shown in FIG. Further, in the case of the two-pass method in which the formation of an image is completed by ejecting ink in two main scanning operations for each position on the recording medium P, the predetermined distance is W/2.

When the sub-scanning operation ends, at timing tb2, the second carriage 21B starts to move backward. After starting to move, the second carriage 21B accelerates at a predetermined acceleration and reaches a predetermined speed before reaching the position pp2. After that, the second carriage 21B ejects ink from the ink ejection head 213 while moving at a constant speed within the image forming area Rp to perform backward printing.

Next, at timing ta2 when the second carriage 21B reaches the position pb, the movement of the first carriage 21A is started. After starting to move, the first carriage 21A accelerates at a predetermined acceleration and reaches a predetermined speed before reaching the position pp2. After that, the first carriage 21A ejects ink from the ink ejection head 213 while moving at a constant speed within the image forming area Rp to perform backward printing.
The speed of the first carriage 21A and the speed of the second carriage 21B during backward printing are also equal to each other.

At timing tx2 when the first carriage 21A reaches position pr2, the preceding second carriage 21B reaches position pr1. In other words, the movement start timing ta2 of the first carriage 21A is determined so that the second carriage 21B reaches the position pr1 when the first carriage 21A reaches the position pr2. In other words, when the time required for the first carriage 21A to reach the position pr2 after it starts moving is tm2 (=tx2-ta2), the second carriage 21B reaches the position pr1. The position of the second carriage 21B at a timing earlier than the timing by time tm2 is defined as the position pb.
Therefore, only the second carriage 21B is positioned in the restricted area R1 before the timing tx2, and only the first carriage 21A is positioned in the restricted area R1 after the timing tx2. Therefore, only one carriage 21, which is the upper limit number, is positioned in the restricted area R1 at an arbitrary timing during backward printing.

After finishing the backward printing, the second carriage 21B and the first carriage 21A stop at the standby position in the non-restricted area R2.
When each carriage 21 stops, the sub-scanning operation by the transport section 10 is performed.
Thereafter, similar operations are repeated until the image formation on the recording medium P is completed.

Also, during the period from the start of movement of the first carriage 21A at timing ta1 in FIG. Alternatively, the second carriage 21B located at the top of the capping unit 24 may be used to perform the discharge operation. That is, by controlling the linear motor 215 so that when any carriage 21 is positioned in the restricted area R1, any other carriage 21 is positioned at the ink receiving position, the standby time of the carriage 21 is reduced. It can be used to perform a spitting action. It should be noted that the first carriage 21A may also be caused to perform the discharge operation while it is positioned at the standby position in the non-restricted area R2.

During the period from the start of movement of the second carriage 21B at timing tb2 in FIG. The cleaning operation by the cleaning unit 23 may be performed on a certain first carriage 21A. That is, by controlling the linear motor 215 so that any other carriage 21 is positioned at the cleaning position when any carriage 21 is positioned in the restricted area R1, the waiting time of the carriage 21 is utilized. to perform a cleaning operation. The second carriage 21B may also be cleaned by the cleaning unit 23 while it is positioned at the standby position in the non-restricted area R3.

Next, a control procedure of image forming processing for performing the above image forming operation by each part of the inkjet recording apparatus 1 will be described.
FIG. 8 is a flow chart showing a control procedure by the control unit 30 for image forming processing.
The image forming process is started when a print job and image data are input to the control section 30 via the communication section 42 .

When the image forming process is started, the control unit 30 sends a control signal to the transport motor 14 to operate the transport unit 10 to transport the recording medium P to the image forming start position (step S101).

The control unit 30 starts the movement of the leading carriage 21 and the main scanning operation (step S102). That is, the control unit 30 sends a control signal to the linear motor 215 of the leading carriage 21 to start moving the carriage 21 and also starts receiving signals from the linear encoder 216 to determine the position of the carriage 21 . Get location information. In addition, control signals and image data are sent to the head drive board 214 at appropriate timing according to the position of the carriage 21, and the ink ejection head 213 ejects ink.

The control unit 30 determines whether or not there is a subsequent carriage 21 that has not yet moved (step S103). It is determined whether or not the carriage 21 that has started to move has reached a predetermined position (step S104). That is, the control unit 30 determines whether or not the first carriage 21A, which has started to move, has reached the position pa shown in FIG. If it is determined that the carriage 21 has not reached the predetermined position ("NO" in step S104), the control section 30 executes the process of step S104 again. If it is determined that the carriage 21 has reached the predetermined position ("YES" in step S104), the control unit 30 shifts the process to step S102 to start the next movement of the carriage 21 and the main scanning operation. Let

If it is determined in the process of step S103 that there is no subsequent carriage 21 that has not yet moved (“NO” in step S103), the control unit 30 moves each carriage 21 to complete movement and moves to the non-restricted area R2 or R3. (step S105). If it is determined that the movement of any carriage 21 has not been completed ("NO" in step S105), the control unit 30 executes the process of step S105 again.

When it is determined that the movement of all the carriages 21 is completed ("YES" in step S105), the control section 30 determines whether or not the image formation on the recording medium P is completed (step S106). . If it is determined that image formation has not been completed ("NO" in step S106), the control section 30 causes the conveying section 10 to perform the sub-scanning operation (step S107). That is, the control unit 30 sends a control signal to the transport motor 14 to operate the transport unit 10, thereby transporting the recording medium P by a predetermined distance. When the sub-scanning operation ends, the control unit 30 switches between the forward path and the backward path (step S108), and shifts the process to step S102.

If it is determined in the process of step S106 that the image formation has been completed ("YES" in step S106), the control section 30 terminates the image formation process.
Steps S102 to S104 in the image forming process correspond to drive control steps.

Next, the effect of shortening the image forming time by the method of driving the carriage 21 described above will be described in comparison with a comparative example.
FIG. 9 is a diagram showing the arrangement of the ink ejection heads 213 on the carriage 21 according to the comparative example.
10A and 10B are diagrams for explaining an image forming process in a comparative example and an example of the configuration of the present embodiment.

As shown in FIG. 9, in the carriage 21 of the comparative example, ink ejection heads 213Y, 213M, 213C, 213K, 213LM, 213LC, 213O, and 213G are mounted one each. are arranged in a houndstooth pattern.
The inkjet recording apparatus of the comparative example forms an image using only this one carriage 21 . Specifically, for each position on the recording medium P, first, the ink of the basic color is discharged from the ink discharge heads 213Y, 213M, 213C, and 213K on the downstream side in the transport direction, and then the recording medium P is moved by the width W/2. A sub-scanning operation for conveying is executed, and auxiliary color ink is discharged from the ink discharge heads 213LM, 213LC, 213O, and 213G on the upstream side in the conveying direction.

Therefore, as shown in the upper part of FIG. 10, in the inkjet printing apparatus of the comparative example, an image portion having a width of W/2 in the sub-scanning direction is completed by one-way main scanning operation in the forward or backward pass. Therefore, in order to form an image with a width of 2W, for example, two reciprocating main scanning operations are required, and three sub-scanning operations are performed during that time.

On the other hand, according to the example of the present embodiment, two ink ejection heads 213 for each color are provided as shown in FIG. 3, so that each color ink can be ejected over the width W. . Therefore, as shown in the lower part of FIG. 10, the one-way main scanning operation by the two carriages 21 can complete an image portion of width W each in the sub-scanning direction. Therefore, in order to form an image with a width of 2W, only one reciprocation of the main scanning operation is sufficient, and only one sub-scanning operation during that time is sufficient.
In addition, in the embodiment, the number of sub-scanning operations is reduced compared to the comparative example. There is a parallel ejection period T during which ink is ejected. By this parallel ejection period T, the image forming time can be further shortened compared to the comparative example.

Next, a modification of the above embodiment will be described. Each of the following modified examples can be appropriately combined without departing from the gist of the present invention.

(Modification 1)
Modification 1 differs from the above-described embodiment in that an image is formed using three carriages 21, and is otherwise the same as the above-described embodiment. Differences from the above embodiment will be described below.

In this modified example, a support member 221 is attached with a first carriage 21A, a second carriage 21B, and a third carriage 21C. The ink ejection heads 213 mounted on each carriage 21 are not particularly limited. Eight ink ejection heads 213 for ejecting ink can be mounted.

Further, in this modification, the carriages 21 are driven so that the number of carriages 21 positioned within the restricted area R1 is two or less at any timing. Therefore, the upper limit of the number of carriages 21 in this modification is "2".

11A and 11B are diagrams illustrating a method of driving the carriage 21 according to Modification 1. FIG.
As shown in FIG. 11, the movement of the first carriage 21A is first started at timing ta1.
Next, at timing tb1 when the first carriage 21A reaches the position pa1, the movement of the second carriage 21B is started.
Next, at timing tc1 when the second carriage 21B reaches position pb1, movement of the third carriage 21C is started.
The velocities of the carriages 21 during forward printing are equal to each other.

At the timing tx1 when the second carriage 21B reaches the position pr1, the preceding first carriage 21A reaches the position pr3 (midpoint between the positions pr1 and pr2). In other words, the movement start timing tb1 of the second carriage 21B is determined so that the first carriage 21A reaches the position pr3 when the second carriage 21B reaches the position pr1. In other words, the first carriage 21A reaches position pr3 when the time required from the start of movement of the second carriage 21B to reaching position pr1 is tn1 (=tx1-tb1). The position of the first carriage 21A at a timing earlier than the timing by time tn1 is determined as the position pa1.

At the timing tx2 when the third carriage 21C reaches the position pr1, the preceding second carriage 21B reaches the position pr3. In other words, the movement start timing tc1 of the third carriage 21C is determined such that the second carriage 21B reaches the position pr3 when the third carriage 21C reaches the position pr1. In other words, the second carriage 21B reaches the position pr3 when the time required for the third carriage 21C to reach the position pr1 after starting to move is tn2 (=tx2-tc1). The position pb1 of the second carriage 21B at a timing earlier than the timing by time tn2 is defined as the position pb1.

Also, at timing tx2, the first carriage 21A reaches position pr2, and after timing tx2 moves outside the restricted area R1. Therefore, before the timing tx2, only the first carriage 21A or only the first carriage 21A and the second carriage 21B are positioned in the restricted area R1, and after the timing tx2, the restricted area R1 is Only the third carriage 21C or only the second carriage 21B and the third carriage 21C will be positioned. Therefore, two or less carriages 21, which is the upper limit number, are positioned in the restricted area R1 at any timing in forward printing.

Each carriage 21 stops at the standby position in the non-restricted area R3 after finishing forward printing.
When the third carriage 21C stops, the sub-scanning operation by the transport section 10 is performed.

When the sub-scanning operation ends, at timing tc2, movement of the third carriage 21C in the return path is started.
Next, at timing tb2 when the third carriage 21C reaches position pc2, movement of the second carriage 21B is started.
Next, at timing ta2 when the second carriage 21B reaches position pb2, movement of the first carriage 21A is started.
The velocities of the carriages 21 during backward printing are also equal to each other.

At the timing tx4 when the second carriage 21B reaches the position pr2, the preceding third carriage 21C reaches the position pr3. In other words, the movement start timing tb2 of the second carriage 21B is determined such that the third carriage 21C reaches the position pr3 when the second carriage 21B reaches the position pr2. In other words, the third carriage 21C reaches the position pr3 when the time required for the second carriage 21B to reach the position pr2 after starting to move is tn3 (=tx4-tb2). The position of the third carriage 21C at a timing earlier than the timing by time tn3 is determined as the position pc2.

At timing tx5 when the first carriage 21A reaches position pr2, the preceding second carriage 21B reaches position pr3. In other words, the movement start timing ta2 of the first carriage 21A is determined so that the second carriage 21B reaches the position pr3 when the first carriage 21A reaches the position pr2. In other words, the second carriage 21B reaches position pr3 when the time required from the start of movement of the first carriage 21A to arrival at position pr2 is tn4 (=tx5-ta2). The position pb2 of the second carriage 21B at a timing earlier than the timing by time tn4 is defined as the above-described position pb2.

At timing tx5, the third carriage 21C reaches position pr1, and after timing tx5 moves outside the restricted area R1. Therefore, before timing tx5, only the third carriage 21C or only the second carriage 21B and the third carriage 21C are positioned in the restricted area R1, and after the timing tx5, the restricted area R1 is Only the first carriage 21A or only the first carriage 21A and the second carriage 21B will be positioned. Therefore, two or less carriages 21, which is the upper limit number, are positioned in the restricted area R1 at any timing during backward printing.

Each carriage 21 stops at the waiting position in the non-restricted area R2 after finishing the backward printing. When all the carriages 21 stop, the sub-scanning operation by the conveying section 10 is performed.
Thereafter, similar operations are repeated until the image formation on the recording medium P is completed.

Although the above is an example in which the upper limit number is set to "2", the upper limit number may be set to "1" even when the number of carriages 21 is three.
Also, the number of carriages can be four or more. Also in this case, the movement start timing of each carriage 21 is controlled so that the number of carriages 21 positioned in the restricted area R1 at any timing is equal to or less than the upper limit number. When the number of carriages is four, the upper limit number is set to any one of "1" to "3".

(Modification 2)
Next, Modification 2 of the above embodiment will be described. This modification differs from the above-described embodiment in the method of determining the movement start timing of each carriage 21, and is otherwise the same as the above-described embodiment. Differences from the above embodiment will be described below.

In this modification, the control unit 30 determines the movement start timing of the next carriage 21 based on the elapsed time after the movement of one carriage 21 among the plurality of carriages 21 is started. For example, the control unit 30 starts the movement of the second carriage 21B after the time (tb1-ta1) has elapsed after the movement of the first carriage 21A was started at the timing ta1 in FIG. The time (tb1-ta1) may be determined in advance and stored as setting data in the storage unit 34 or the like, or may be calculated each time based on the acceleration and speed of the first carriage 21A.
The same applies to the return path, and after the second carriage 21B starts to move at timing tb2, the first carriage 21A starts to move at the timing when the time (ta2-tb2) has elapsed.
According to the control method of this modified example, each carriage 21 can be driven so that the position of each carriage 21 at each point in time is the same as in FIG.

FIG. 12 is a flowchart showing a control procedure by the control unit 30 for image forming processing according to Modification 2. As shown in FIG.
The flowchart of FIG. 12 corresponds to the flowchart of FIG. 8 with step S104 changed to step S104a. Differences from the flowchart of FIG. 8 will be described below.
In the image forming process of FIG. 12, when it is determined in the process of step S103 that there is a following carriage 21 that has not yet moved ("YES" in step S103), the controller 30 moves the carriage 21 in step S102. It is determined whether a predetermined time (for example, the above-mentioned time (tb1-ta1) or time (ta2-tb2)) has passed since the start of movement (step S104a). If it is determined that the predetermined time has not elapsed since the start of movement of the carriage 21 ("NO" in step S104a), the control section 30 executes the process of step S104a again. If it is determined that the predetermined time has passed since the start of movement of the carriage 21 ("YES" in step S104a), the control unit 30 shifts the process to step S102 to perform the next movement of the carriage 21 and main scanning. start the action.

(Modification 3)
Next, Modification 3 of the above embodiment will be described. In this modification, two carriages 21 are mounted with ink ejection heads 213 for ejecting ink of the same color. It differs from the above-described embodiment in that it is complemented by the above-described embodiment, but the other points are the same as the above-described embodiment. Differences from the above embodiment will be described below.

FIG. 13 is a diagram showing the arrangement of the ink ejection heads 213 on the carriage 21 according to Modification 3. As shown in FIG.
In this modification, two ink ejection heads 213Y, 213M, 213C, and 213K of basic colors are mounted on each of the first carriage 21A and the second carriage 21B, and eight ink ejection heads 213 are arranged. are the same. Each ink discharge head 213 is arranged so that the position of the nozzles N in the sub-scanning direction on the first carriage 21A and the position of the nozzles N in the sub-scanning direction on the second carriage 21B match. In this way, by mounting the image forming operation section 212 having the ink ejection heads 213 for ejecting ink of the same color on the first carriage 21A and the second carriage 21B, the recording medium P on the loading surface 13a can be On the other hand, the ink ejected from the ink ejection head 213 of each carriage 21 can be deposited on the recording medium P in an overlapping manner. Accordingly, the density of the image can be adjusted by adjusting the amount of ink ejected from the ink ejection head 213 of each carriage 21 .

14A and 14B are diagrams for explaining complementary ejection of ink in Modification 3. FIG.
As shown in FIG. 14, in this modification, when the nozzle Na in the ink ejection head 213 of the first carriage 21A is a defective nozzle that cannot eject ink, the ink ejection head 213 of the second carriage 21B Complementary ejection is performed by the nozzles Nb having the same position in the transport direction. That is, the control unit 30 causes the ink ejection heads 213 of the other carriages 21 to eject the ink that has failed to be ejected from the ink ejection heads 213 of some of the carriages 21 onto the recording medium P on the mounting surface 13a. Complemented by the ink that was applied. This suppresses deterioration of image quality due to defective nozzles.
Note that the nozzles that perform complementary ejection are not limited to the nozzles Nb that are located at the same position in the transport direction, and neighboring nozzles that are close to the nozzle Nb in the transport direction may be used for complementary ejection.
Further, the target of complementation is not limited to defective nozzles that cannot eject ink. It is also possible to stop ejection of ink from the nozzle N that is defective in ink ejection amount or ejection direction, and to make the ink ejection head 213 of the other carriage 21 compensate for this.

(Modification 4)
Next, Modification 4 of the above embodiment will be described. This modification differs from the above embodiment in that two carriages 21 are mounted with ink ejection heads 213 that eject ink of the same color, and in that the positional relationship of the ink ejection heads 213 in each carriage 21 is different. is the same as the above embodiment. Differences from the above embodiment will be described below.

FIG. 15 is a diagram showing the arrangement of the ink ejection heads 213 on the carriage 21 according to Modification 4. As shown in FIG.
In Modification 4, as in Modification 3, each of the first carriage 21A and the second carriage 21B is equipped with two basic color ink ejection heads 213Y, 213M, 213C, and 213K. The arrangement of the two ink ejection heads 213 is the same.
However, as shown in FIG. 15, in this modification, the position of the nozzles N in the sub-scanning direction (arrangement direction of the nozzles N) of the first carriage 21A is different from that of the nozzles N of the second carriage 21B in the sub-scanning direction. About position and different. That is, the ink ejection heads 213 of each carriage 21 are arranged in a positional relationship in which the positions of the nozzles N in the sub-scanning direction are different from each other. As a result, the image recording resolution in the sub-scanning direction can be doubled.

It should be noted that three or more carriages 21 may be provided and the positions of the nozzles N of each carriage 21 may be different. This makes it possible to further increase the recording resolution in the sub-scanning direction.
In the example of FIG. 15, the positions of the nozzles N are varied by adjusting the mounting positions of the ink ejection heads 213 in each carriage 21. However, by adjusting the relative positions of the carriages 21 in the sub-scanning direction, The position of the nozzle N may be varied.

(Modification 5)
Next, Modification 5 of the above embodiment will be described. This modification differs from the above embodiment in that the image forming operation unit 212 mounted on the carriage 21 has an ultraviolet irradiation unit 217 and a functional liquid applying unit 218, and the other points are the same as the above embodiment. is. Differences from the above embodiment will be described below.

FIG. 16 is a diagram showing the configuration of the carriage 21 according to Modification 5. As shown in FIG.
In this modification, the image forming operation unit 212 of the first carriage 21A includes an ultraviolet irradiation unit 217 that irradiates the ink ejected onto the recording medium P with ultraviolet rays, and a predetermined functional liquid that is applied to the recording medium P. and a functional liquid applying unit 218 for applying the functional liquid. The ultraviolet irradiation section 217 is arranged downstream of the eight ink ejection heads 213 in the main scanning direction (the leading side in the outward path), and the functional liquid applying section 218 is arranged downstream of the ultraviolet irradiation section 217 in the main scanning direction. ing.
Similarly, the image forming operation section 212 of the second carriage 21B also has an ultraviolet irradiation section 217 and a functional liquid applying section 218 . In the second carriage 21B, the ultraviolet irradiation section 217 is arranged upstream of the eight ink ejection heads 213 in the main scanning direction (the leading side in the return path). It is arranged on the upstream side in the scanning direction.
Note that the positional relationship between the ultraviolet irradiation section 217 and the functional liquid applying section 218 may be reversed.

The ink ejection head 213 of this modified example ejects ultraviolet curable ink that is hardened by increasing its viscosity when irradiated with ultraviolet rays. The ultraviolet irradiation unit 217 irradiates the ink ejected onto the recording medium P from the ink ejection head 213 with ultraviolet rays to cure the ink. The operation of irradiating ultraviolet rays by the ultraviolet irradiation unit 217 is one aspect of the operation related to image formation on the recording medium P on the placement surface 13a.
In forward printing, the second carriage 21A and the second carriage 21B positioned on the trailing end side with respect to the traveling direction of the carriage 21 with respect to the ink ejected onto the recording medium P by the ink ejection heads 213 of the first carriage 21A and the second carriage 21B. Ultraviolet rays are irradiated by the ultraviolet irradiation section 217 of the carriage 21B.
In backward printing, the second carriage 21B and the first carriage 21A are positioned on the rear end side of the traveling direction of the carriage 21 with respect to the ink ejected onto the recording medium P by the ink ejection heads 213 of the first carriage 21A. Ultraviolet rays are irradiated by the ultraviolet irradiation section 217 of the first carriage 21A.

The functional liquid applying unit 218 applies functional liquid for improving the image quality of the printed image to the recording medium P before the ink is ejected. As the functional liquid, for example, a pretreatment agent for making it easier for ink to permeate the recording medium P, a pretreatment agent for making it difficult for the ink to permeate the recording medium P such as a fabric and suppressing bleeding, and ink. and an aggregating agent that agglomerates dispersed materials such as pigment particles in the ink to increase the viscosity of the ink. The operation of applying the functional liquid by the functional liquid applying unit 218 is one aspect of the operation related to image formation on the recording medium P on the mounting surface 13a.
In forward printing, the functional liquid is applied to the recording medium P by the functional liquid applying unit 218 of the first carriage 21A, which is located on the leading side in the traveling direction of the carriage 21. Subsequently, the first carriage 21A and the second carriage 21A are applied. Ink is ejected by the ink ejection head 213 of the carriage 21B.
In reverse printing, functional liquid is applied to the recording medium P by the functional liquid applying unit 218 of the second carriage 21B, which is located on the leading side in the traveling direction of the carriage 21. Subsequently, the functional liquid is applied to the recording medium P. Ink is ejected by the ink ejection head 213 of the first carriage 21A.

In this modified example, an example in which the image forming operation unit 212 mounted on each carriage 21 includes an ink ejection head 213, an ultraviolet irradiation unit 217, and a functional liquid applying unit 218 has been described. It is not limited to this.
For example, some of the carriages 21 may be mounted with an image forming operation section 212 having only an ultraviolet irradiation section 217 . In this case, the carriage 21 having the ultraviolet irradiation unit 217 mounted thereon is provided on both sides of the carriage 21 having the ink discharge head 213 mounted thereon. The portion 217 can irradiate ultraviolet rays.
Also, some of the carriages 21 may be mounted with the image forming operation section 212 having only the functional liquid applying section 218 . In this case, by providing the carriage 21 with the functional liquid applying unit 218 mounted on both sides of the carriage 21 with the ink discharge head 213 mounted thereon, the recording medium P before the ink is discharged in both the outward path and the return path. can be applied with the functional liquid by the functional liquid applying unit 218.
Further, the inkjet recording apparatus 1 may have a configuration in which one of the ultraviolet irradiation section 217 and the functional liquid applying section 218 is not provided.

As described above, the inkjet recording apparatus 1 as an image forming apparatus according to the present embodiment includes the conveying belt 13 having the mounting surface 13a on which the recording medium P is mounted, and the recording medium P on the mounting surface 13a. A plurality of carriages 21 each mounted with an image forming operation unit 212 that performs an operation related to image formation, and the plurality of carriages 21 can be reciprocated along a predetermined movement path Rmv passing over the placement surface 13a. When there are a supporting member 221 that supports, a linear motor 215 that independently moves each of the plurality of carriages 21 along the movement path Rmv, and at least two or more of the plurality of carriages 21 that are moving, The linear motor 215 is driven so that the number of carriages 21 within a predetermined restricted area R1 on the movement path Rmv among the plurality of carriages 21 is equal to or less than a predetermined upper limit number that is less than the number of carriages 21 included in the plurality of carriages 21 . and a control unit 30 (driving control means) for controlling the
According to this, the weight of the support member 221 that is applied to the restricted region R1 can be suppressed to a predetermined value or less at an arbitrary timing. Therefore, the deflection of the support member 221 can be suppressed within a desired range. Therefore, it is possible to prevent the carriage 21 and the recording medium P from being close to each other due to the bending of the support member 221, thereby preventing the ink landing position from being shifted or the carriage 21 coming into contact with the recording medium P. can be done. As a result, even if two or more carriages out of the plurality of carriages 21 are moved at the same time, an image can be properly formed, so that the image can be formed in a short period of time and the throughput of image formation can be increased. In addition, since it is sufficient to use the support member 221 that has the strength to withstand the weight of the upper limit number of carriages 21 in the restricted area R1, the cost of the support member 221 can be reduced or reduced. The support member 221 can be made longer while suppressing the rise. By lengthening the support member 221, an image can be formed in a short time even on a recording medium P having a larger size in the main scanning direction. In addition, even if a plurality of carriages 21 are attached to one support member 221, deflection during driving can be suppressed. can be shared with Therefore, the manufacturing cost of the device can be effectively suppressed.

Further, the control unit 30 acquires position information (position information acquiring means) relating to the position of each of the plurality of carriages 21 on the movement path Rmv, and after starting the movement of one carriage 21 among the plurality of carriages 21, , determines the movement start timing of the next carriage 21 based on the position information relating to the position of the one carriage 21 (drive control means). According to this, it is possible to form an image with a high throughput while suppressing the bending of the support member 221 with a simple control.

Further, the control unit 30 according to Modification 2 determines the movement start timing of the next carriage 21 based on the elapsed time after the movement of one carriage 21 among the plurality of carriages 21 is started. According to this, it is possible to form an image with a high throughput while suppressing the bending of the support member 221 with a simple control.

Further, the image forming operation unit 212 operates when the carriage 21 on which the image forming operation unit 212 is mounted is located within the image forming area Rp in the moving route Rmv, and the restricted area R1 is at least the image forming area Rp. Including some. According to this, it is possible to prevent the supporting member 221 from bending in the image forming area Rp and the deterioration of the image quality.

Also, the restricted area R1 is set inside both ends of the image forming area Rp. According to this, even when one carriage 21 is within the restricted area R1, the other carriages 21 can be positioned outside the restricted area R1 in the image forming area Rp. That is, two or more carriages 21 can be simultaneously positioned within the image forming area Rp. By simultaneously ejecting ink from the ink ejection heads 213 of the carriages 21 at this timing, an image can be formed in a shorter time.

Further, the control unit 30 controls the linear motor 215 (driving control means) so that two or more of the plurality of carriages 21 are simultaneously positioned within the image forming area Rp at any timing. According to this, it is possible to simultaneously eject ink onto the same recording medium P from the ink ejection heads 213 of two or more carriages 21 . Therefore, an image can be formed in a shorter time.

An image forming operation unit 212 having an ink ejection head 213 that ejects ink onto the recording medium P is mounted on at least part of the plurality of carriages 21 , and the control unit 30 controls movement of the carriage 21 . The ink is ejected from the ink ejection head 213 at the corresponding timing (ejection control means). According to this, it is possible to suppress deterioration in image quality due to bending of the support member 221 and form an image appropriately.

Further, a cleaning unit 23 is provided for cleaning the ink ejection head 213 of the carriage 21 located at a predetermined cleaning position outside the image forming area Rp. , the linear motor 215 is controlled (driving control means) so that at least one of the plurality of carriages 21 on which the ink discharge head 213 is mounted is positioned at the cleaning position. According to this, the ink discharge head 213 can be cleaned during execution of the image forming operation. Therefore, it is possible to further increase the throughput of image formation compared to the conventional technique of cleaning the ink ejection head 213 while the image formation operation is not performed. Further, since the cleaning unit 23 can be shared by a plurality of carriages 21, the cost can be further reduced.

Also provided is a capping unit 24 that receives ink ejected from the ink ejection head 213 of the carriage 21 located at a predetermined ink receiving position outside the image forming area Rp. The linear motor 215 is controlled so that at least one of the plurality of carriages 21 on which the ink discharge head 213 is mounted is positioned at the ink receiving position when one of the carriages 21 is positioned within the restricted area R1 (driving control means). According to this, the ejection operation can be performed by the ink ejection head 213 during execution of the image forming operation. Therefore, it is possible to further increase the throughput of image formation as compared with the conventional technology in which the ink discharge head 213 performs the ejection operation during the period in which the image formation operation is not performed. Further, since the capping unit 24 can be shared by a plurality of carriages 21, the cost can be further reduced.

At least one of the plurality of carriages 21 is mounted with an image forming operation section 212 having a plurality of first ink ejection heads 213 that eject a plurality of basic color inks. At least one of the others is mounted with an image forming operation section 212 having a second ink ejection head 213 for ejecting auxiliary color inks other than a plurality of basic colors. A first mode in which ink is ejected by the ink ejection head 213 and the second ink ejection head 213, and a second mode in which ink is ejected by the first ink ejection head 213 and ink is not ejected by the second ink ejection head 213. The ink is ejected by the ink ejection head 213 in one mode selected from the mode 2 (ejection control means). According to this, it is possible to easily switch between image formation using a combination of basic colors and auxiliary colors and image formation using only basic colors. Moreover, it is possible to effectively suppress the bending of the support member 221 in the first mode in which the basic color and the auxiliary color are combined.

Further, in Modification 3, each of at least two carriages 21 out of the plurality of carriages 21 is mounted with an image forming operation section 212 having an ink ejection head 213 that ejects ink of the same color. A reference numeral 30 causes the ink ejected from the ink ejection heads 213 of the at least two carriages 21 to land on the recording medium P on the mounting surface 13a in an overlapping manner (ejection control means). According to this, the density of the formed image can be adjusted by adjusting the amount of ink ejected from the ink ejection head 213 of each carriage 21 .

Further, the control unit 30 of Modification 3 ejects ink that has failed to be ejected from the ink ejection heads 213 of some of the at least two carriages 21 onto the recording medium P on the mounting surface 13a. The ink ejected from the ink ejection head 213 of any other carriage 21 of the at least two carriages 21 is complemented (ejection control means). According to this, even if the ink ejection head 213 of any of the carriages 21 has an ink ejection failure nozzle N, deterioration of the image quality can be suppressed.

In Modification 4, each of at least two carriages 21 out of the plurality of carriages 21 is equipped with an image forming operation section 212 having an ink ejection head 213 that ejects ink of the same color. The ejection head 213 is provided with a plurality of nozzles N each ejecting ink at predetermined intervals in an arrangement direction orthogonal to the movement direction of the carriage 21 along the movement path Rmv. The ink ejection heads 213 are arranged in a positional relationship in which the positions of the nozzles N in the arrangement direction are different from each other. According to this, it is possible to increase the recording resolution of an image in the sub-scanning direction with a simple configuration.

Further, in Modification 5, the ink ejection head 213 ejects ink that cures when irradiated with ultraviolet rays, and at least some of the plurality of carriages 21 irradiate the ink ejected onto the recording medium P with ultraviolet rays. An image forming operation section 212 having an ultraviolet irradiation section 217 is mounted. According to this, the ink can be cured during the main scanning operation of the carriage 21 . Therefore, since there is no need to provide a separate device for irradiating ultraviolet rays outside the carriage 21, costs can be reduced.

Further, in Modification 5, at least part of the plurality of carriages 21 is equipped with an image forming operation section 212 having a functional liquid applying section 218 that applies a predetermined functional liquid to the recording medium P. FIG. According to this, the functional liquid can be applied to the recording medium P during the main scanning operation of the carriage 21 . Therefore, since there is no need to provide a separate device for applying the functional liquid outside the carriage 21, costs can be reduced.

The inkjet recording apparatus 1 also includes a transport section 10 that transports the recording medium P in the transport direction by moving the placement surface 13a of the transport belt 13 in the transport direction that intersects the moving direction of the carriage 21 . According to this, an image can be formed on a desired range of the recording medium P by repeating the main scanning operation of the carriage 21 and the sub-scanning operation of the transport section 10 .

Further, in the driving method of the carriage 21 according to the present embodiment, when there are at least two moving carriages 21 among the plurality of carriages 21, the predetermined restricted region R1 in the movement route Rmv among the plurality of carriages 21 A drive control step is included to control the linear motor 215 so that the number of carriages 21 inside the carriage 21 is less than the number of carriages 21 included in the plurality of carriages 21 and is equal to or less than a predetermined upper limit. According to such a method, it is possible to suppress the occurrence of problems caused by the bending of the support member 221 and form an image appropriately. Further, it is possible to form an image in a short time and increase the throughput of image formation while suppressing the cost.

It should be noted that the present invention is not limited to the above embodiments, and various modifications are possible.
For example, the number, arrangement, and number of colors of the ink ejection heads 213 mounted on the carriage 21 in the above-described embodiment are examples, and can be appropriately changed according to the content of the image to be formed.

Further, in the above embodiment, the restricted area R1 is set inside both ends of the image forming area Rp, but the present invention is not limited to this, and the restricted area R1 may match the image forming area Rp, It may be an area that includes the entire image forming area Rp and is wider than the image forming area Rp.

In the above embodiment, the cleaning unit 23 is provided only on one side of the movement path of the carriage 21 in the main scanning direction. Alternatively, the cleaning unit 23 may be provided on both sides of the movement path. By doing so, the cleaning operation for the ink ejection head 213 of the carriage 21 can be performed in each waiting time after the end of forward printing and after the end of backward printing.

In the above embodiment, the capping unit 24 is provided only on one side of the movement path of the carriage 21 in the main scanning direction. Alternatively, the capping unit 24 may be provided on both sides of the movement path. By doing so, the ink ejection head 213 of the carriage 21 can be caused to perform the ejection operation during each waiting time after the end of forward printing and after the end of backward printing.

Also, the auxiliary colors are not limited to LM, LC, O, and G, and any auxiliary color ink other than the basic colors, such as B (blue) and R (red), can be used.

Although several embodiments of the present invention have been described, the scope of the present invention is not limited to the above-described embodiments, and includes the scope of the invention described in the claims and equivalent ranges thereof. .

1 Inkjet recording device (image forming device)
10 Conveying Unit 11 Driving Roller 12 Driven Roller 13 Conveying Belt (Placement Member)
13a Placement surface 14 Transport motor 20 Recording units 21, 21A, 21B, 21C Carriage 211 Housing 211a Bottom surface 212 Image forming operation unit 213 Ink discharge head 214 Head driving substrate 215 Linear motor (driving unit)
216 Linear encoder 217 Ultraviolet irradiation unit 218 Functional liquid application unit 22 Main scanning rail 221 Support member 222 Linear guide 223 Linear motor magnet 224 Linear scale 225 Support 23 Cleaning unit 24 Capping unit 30 Control unit (drive control means, position information acquisition means, discharge control means)
31 CPUs
32 RAMs
33 ROMs
34 Storage unit 41 Operation display unit 42 Communication unit 43 Bus N Nozzle P Recording medium R1 Restricted areas R2, R3 Non-restricted area Rmv Moving path Rp Image forming area

Claims (17)

a mounting member having a mounting surface on which the recording medium is mounted;
a plurality of carriages each mounted with an image forming operation unit that performs an operation related to image formation on the recording medium on the mounting surface;
a support member that supports the plurality of carriages so that they can reciprocate along a predetermined movement path passing through the mounting surface;
a driving unit that independently moves each of the plurality of carriages along the movement path;
When there are at least two moving carriages among the plurality of carriages, the number of carriages among the plurality of carriages within a predetermined restricted area in the movement path is the number of carriages included in the plurality of carriages. a drive control means for controlling the drive unit so that the number is equal to or less than a predetermined upper limit number that is less than the number of
An image forming apparatus comprising: position information acquisition means for acquiring position information relating to the position of each of the plurality of carriages on the movement path;
The drive control means, after starting movement of one of the plurality of carriages, determines timing for starting movement of the next carriage based on the position information relating to the position of the one carriage. The image forming apparatus according to claim 1. 2. An image forming apparatus according to claim 1, wherein said drive control means determines the movement start timing of the next carriage based on the elapsed time after starting movement of one of said plurality of carriages. Device. The image forming operation unit performs the operation when the carriage on which the image forming operation unit is mounted is within a predetermined image forming area of the movement path,
4. The image forming apparatus according to claim 1, wherein the restricted area includes at least part of the image forming area. 5. The image forming apparatus according to claim 4, wherein the restricted area is set inside both ends of the image forming area. 6. The driving control means controls the driving section so that two or more of the plurality of carriages are simultaneously positioned within the image forming area at any timing. The image forming apparatus according to . At least part of the plurality of carriages is mounted with the image forming operation unit having an ink ejection head for ejecting ink onto the recording medium,
7. The image forming apparatus according to claim 4, further comprising ejection control means for causing the ink ejection head to eject ink at a timing corresponding to movement of the carriage. . a cleaning unit that cleans the ink ejection head of the carriage at a predetermined cleaning position outside the image forming area;
The drive control means causes at least one of the plurality of carriages, on which the ink discharge head is mounted, to be positioned at the cleaning position when at least one of the plurality of carriages is positioned within the restricted area. 8. The image forming apparatus according to claim 7, wherein the driving section is controlled in such a manner that an ink receiving portion for receiving ink ejected from the ink ejection head of the carriage located outside the image forming area at a predetermined ink receiving position;
The drive control means is arranged such that, when at least one of the plurality of carriages is positioned within the restricted area, at least one of the plurality of carriages on which the ink discharge head is mounted is positioned at the ink receiving position. 9. The image forming apparatus according to claim 7, wherein the driving unit is controlled so as to At least one of the plurality of carriages is mounted with the image forming operation section having a plurality of first ink ejection heads for ejecting a plurality of basic color inks,
At least one other of the plurality of carriages is mounted with the image forming operation section having a second ink ejection head for ejecting auxiliary color ink other than the plurality of basic colors,
The ejection control means has a first mode for ejecting ink by the first ink ejection head and the second ink ejection head, and a second mode for ejecting ink by the first ink ejection head and the second mode. 10. The image according to any one of claims 7 to 9, wherein ink is ejected from the ink ejection head in one mode selected from a second mode in which the ink ejection head does not eject ink. forming device. each of at least two carriages among the plurality of carriages is mounted with the image forming operation unit having the ink ejection head that ejects ink of the same color;
The ejection control means is characterized in that the ink ejected from the ink ejection heads of the at least two carriages is ejected from the ink ejection heads of the at least two carriages onto the recording medium on the mounting surface, and the ink is deposited on the recording medium. The image forming apparatus according to any one of claims 7 to 10. each of at least two carriages among the plurality of carriages is mounted with the image forming operation unit having the ink ejection head that ejects ink of the same color;
The ejection control means controls ink that has failed to be ejected from the ink ejection heads of some of the at least two carriages onto the recording medium on the mounting surface. 12. The image forming apparatus according to any one of claims 7 to 11, wherein ink ejected from the ink ejection head of any other carriage is complemented. each of at least two carriages among the plurality of carriages is mounted with the image forming operation unit having the ink ejection head that ejects ink of the same color;
each of the ink ejection heads is provided with a plurality of nozzles for ejecting ink at predetermined intervals in an arrangement direction perpendicular to the movement direction of the carriage along the movement path;
13. The method according to any one of claims 7 to 12, wherein the ink ejection heads of each of the at least two carriages are arranged in a positional relationship in which the positions of the nozzles in the arrangement direction are different from each other. image forming device. The ink ejection head ejects ink that cures when irradiated with ultraviolet rays,
13. The image forming operation section having an ultraviolet irradiation section for irradiating the ink ejected onto the recording medium with ultraviolet rays is mounted on at least a part of the plurality of carriages. The image forming apparatus according to any one of . 14. The image forming operation section having a functional liquid applying section for applying a predetermined functional liquid to the recording medium is mounted on at least a part of the plurality of carriages. The image forming apparatus according to any one of . A conveying unit that conveys the recording medium in the conveying direction by moving the mounting surface of the mounting member in the conveying direction that intersects the moving direction of the carriage along the moving path. The image forming apparatus according to any one of claims 1 to 15. a mounting member having a mounting surface on which a recording medium is mounted; a plurality of carriages each mounted with an image forming operation unit that performs an operation related to forming an image on the recording medium on the mounting surface; a support member that supports a plurality of carriages so as to be able to reciprocate along a predetermined movement path passing through the mounting surface; a drive unit that independently moves each of the plurality of carriages along the movement path; A method for driving a carriage in an image forming apparatus comprising
When there are at least two moving carriages among the plurality of carriages, the number of carriages among the plurality of carriages within a predetermined restricted area in the movement path is the number of carriages included in the plurality of carriages. A method of driving a carriage, comprising: a drive control step of controlling the drive unit so that the number of the carriages is equal to or less than a predetermined upper limit number which is less than the number of .

Images