Image forming device

Abstract

To enable coexistence of speeding up of printing in an image forming device and suppression of image quality deterioration of a printing image.SOLUTION: An image forming device 100 comprises a controller 10 controlling actions of a first carriage 1A, a second carriage 1B and a sub-scanning carriage 50. The controller 10 can execute a first printing pattern executing printing to the whole of a recording medium M by the second carriage 1B after completing printing to the whole of the recording medium M by the first carriage 1A and a second printing pattern executing printing by simultaneously driving the first carriage 1A and the second carriage 1B by executing printing to a part of the recording medium M by the second carriage 1B after completing printing to the part of the recording medium M by the first carriage 1A, and determines the execution possibility of the second printing pattern based on a drying time of liquid ejected to the recording medium M after printing by the first carriage 1A.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus. [Background technology]

[0002] Generally, in an inkjet image forming device, an image is formed on a recording medium by ejecting liquid from the liquid ejection head onto a predetermined area of ​​the recording medium while moving a carriage carrying the liquid ejection head back and forth in a main scanning direction perpendicular to the transport direction of the recording medium.

[0003] Patent Document 1 describes a configuration in which two carriages are provided and the two carriages are driven independently to form images, thereby increasing the printing speed. Summary of the Invention [Problem to be solved by the invention]

[0004] In a conventional configuration with two carriages, the following two printing patterns are possible. In the first printing pattern, when the first carriage performs white printing and the second carriage performs color printing, after the first carriage completes white printing on the entire recording medium, the second carriage performs color printing on top of that. In the second printing pattern, while the first carriage is printing white, the second carriage simultaneously performs color printing on the part of the recording medium where printing by the first carriage has been completed. In the second printing pattern, printing can be performed by two carriages simultaneously, thereby speeding up printing.

[0005] However, in the case of the second print pattern, the white ink drying time between the end of white printing and the start of color printing tends to be shorter, so the image quality may be worse than with the first print pattern.

[0006] SUMMARY OF THE INVENTION An object of the present invention is to enable an image forming apparatus to simultaneously increase the printing speed and prevent deterioration in the quality of printed images. [Means for solving the problem]

[0007] In order to solve the above-mentioned problems, an image forming apparatus according to one aspect of the present invention includes a sub-scanning carriage that moves a recording medium along a transport direction; first and second carriages that are arranged in parallel along the transport direction and each capable of printing on the recording medium along a main scanning direction perpendicular to the transport direction; and a controller that controls the operation of the first carriage, the second carriage, and the sub-scanning carriage, wherein the controller is capable of executing a first printing pattern in which, after printing on the entire recording medium by the first carriage is completed, the second carriage prints on the entire recording medium; and a second printing pattern in which, after printing on a portion of the recording medium by the first carriage is completed, the second carriage prints on the portion of the recording medium and drives the first and second carriages simultaneously to print, and the controller calculates a drying time for liquid ejected onto the recording medium after printing by the first carriage, and determines whether or not the second printing pattern can be executed based on the drying time. [Effects of the Invention]

[0008] This makes it possible to achieve both faster printing in the image forming apparatus and suppression of deterioration in the quality of the printed image. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing a schematic configuration of an image forming apparatus according to an embodiment; [Figure 2] Sequence diagram of the first print pattern [Figure 3] Schematic diagram showing the operation of the first print pattern [Figure 4] Sequence diagram of the second print pattern [Figure 5] Schematic diagram showing the operation of the second print pattern [Figure 6] FIG. 10 is a schematic diagram showing an example of a printing sequence when the printing portion is relatively large; [Figure 7]FIG. 10 is a schematic diagram showing an example of a printing sequence when the printing portion is relatively small. [Figure 8] Flowchart of print pattern selection control in the embodiment DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments will be described with reference to the accompanying drawings. To facilitate understanding of the description, the same components in the drawings will be denoted by the same reference numerals as much as possible, and duplicated descriptions will be omitted.

[0011] In the following description, the X, Y, and Z directions are perpendicular to one another. The X and Y directions are horizontal, and the Z direction is vertical. The X direction is the main scanning direction, which is the left-right direction (width direction) of the image forming apparatus 100. The Y direction is the sub-scanning direction, which is the transport direction of the recording medium M and is the front-rear direction of the image forming apparatus 100. The Z direction is the up-down direction of the image forming apparatus 100. In the following description, the Y positive direction side may also be expressed as the front side of the image forming apparatus 100 or the downstream side in the transport direction, and the Y negative direction side may also be expressed as the rear side of the image forming apparatus 100 or the upstream side in the transport direction. The Z positive direction side may also be expressed as the upper side, and the Z negative direction side may also be expressed as the lower side.

[0012] <General Configuration of Image Forming Apparatus 100> Fig. 1 is a perspective view showing a schematic configuration of an image forming apparatus 100 according to an embodiment. As shown in Fig. 1, the image forming apparatus 100 according to this embodiment is an inkjet type image forming apparatus, and forms an image on a recording medium M by discharging liquid from the liquid discharge head 6 onto a predetermined area of ​​the recording medium M while moving a carriage 1 equipped with a liquid discharge head 6 back and forth in a main scanning direction perpendicular to the recording medium transport direction. Also, as shown in Fig. 1, the image forming apparatus 100 according to this embodiment is equipped with two carriages 1A and 1B, and is configured to increase printing speed by independently driving these two carriages 1A and 1B to form images.

[0013] As shown in FIG. 1, image forming apparatus 100 includes first carriage 1A and second carriage 1B, a pair of first side plates 2A and 2B, a pair of first adjusting plates 3A and 3B as holding members, a pair of second adjusting plates 3B as holding members, a pair of first guide rods 4A and 4B as guide members. Hereinafter, first carriage 1A and second carriage 1B will be referred to as carriage 1, first side plates 2A and 2B as side plates 2, first adjusting plates 3A and 3B as adjusting plates 3, and first guide rods 4 and 4B as guide rods 4. Note that an eccentric cam, which will be described later, is not shown in FIG. 1.

[0014] Each side plate 2 is provided on both the left and right sides of the image forming apparatus 100 and is fixed to a main body 101 of the image forming apparatus 100. The side plates 2 hold an adjustment plate 3 so that it can move in the Y and Z directions.

[0015] Both ends of the guide rod 4 are held by the adjustment plates 3. Each adjustment plate 3 holds two guide rods 4 in the Y direction.

[0016] The carriage 1 is supported by the guide rods 4 so as to be movable on the guide rods 4. The carriage 1 has a plurality of liquid ejection heads 6. The nozzle surfaces of the liquid ejection heads 6 are provided on the lower surface side.

[0017] On the main body 101 of the image forming apparatus 100, a rail 5 is provided along the Y direction.

[0018] The cassette 50 is attached to and detached from the image forming apparatus 100 .

[0019] The cassette 50 has a stage 51 on top thereof. The cassette 50 holds a recording medium to be printed on the stage 51. The recording medium is, for example, fabric.

[0020] By mounting the cassette 50 on the image forming apparatus 100, the stage 51 can be moved onto the rails 5 of the image forming apparatus 100. The stage 51 moves on the rails 5 in the transport direction (Y direction). During this movement, the carriage 1 moves back and forth on the guide rod 4 in the main scanning direction (X direction), while the liquid ejection head 6 of the carriage 1 ejects ink as a liquid onto the recording medium M placed on the stage 51. This forms an image on the recording medium M.

[0021] By having a plurality of carriages 1A and 1B, the image forming apparatus 100 can eject inks of different colors onto the recording medium M, and can increase the printing speed onto the recording medium M, thereby improving the productivity of the apparatus.

[0022] The recording medium M onto which the image forming apparatus 100 shown in FIG. 1 prints may be anything onto which a liquid such as ink can adhere, such as paper, fabric, film, electronic circuit board, electronic components such as piezoelectric elements, powder layers, organ models, and test cells.

[0023] The cassette 50 can also be said to be an element that can move a stage 51 on which the recording medium M is placed in the transport direction (sub-scanning direction), and may also be referred to as the "sub-scanning carriage 50" in the following description.

[0024] Furthermore, the first carriage 1A and the second carriage 1B can each print individually on the recording medium M along a main scanning direction perpendicular to the transport direction. The first carriage 1A and the second carriage 1B are arranged in parallel along the transport direction. In this embodiment, as shown in FIG. 1 and other figures, a configuration is illustrated in which the first carriage 1A is arranged upstream in the transport direction (negative Y direction) and the second carriage 1B is arranged downstream in the transport direction (positive Y direction), but the configuration may be reversed from the example in FIG. 1. In addition, in this embodiment, a configuration is illustrated in which the upstream first carriage 1A performs white printing by ejecting white ink onto the recording medium M, and the downstream second carriage 1B performs color printing by ejecting at least one or more inks of colors other than white onto the recording medium M, but the color combination may be different from this example.

[0025] The image forming apparatus 100 also includes a controller 10. The controller 10 controls the operations of the first carriage 1A, the second carriage 1B, and the sub-scanning carriage 50.

[0026] 1, for convenience of illustration, the controller 10 is shown outside the image forming apparatus 100, but in general the controller 10 is installed inside the image forming apparatus 100. Also, some or all of the functions of the controller 10 may be realized using an external PC or the like.

[0027] The controller 10 can be physically configured as a computer system including a CPU (Central Processing Unit), RAM (Random Access Memory) and ROM (Read Only Memory) as main storage devices, a communication module, an auxiliary storage device, etc. Each function of the controller 10 described above or below is realized by loading predetermined computer software into the CPU, RAM, etc., thereby operating various hardware under the control of the CPU and reading and writing data from and to the RAM.

[0028] <Printing pattern> In a configuration equipped with two carriages 1A and 1B, such as the image forming apparatus 100 of this embodiment, two printing patterns, a "first printing pattern" and a "second printing pattern" described below, can be implemented by the controller 10. Here, the operation of each printing pattern will be explained using as an example a case where white printing is performed by the first carriage 1A and color printing is performed by the second carriage 1B.

[0029] First, the first printing pattern will be described with reference to FIGS. 2 and 3. FIG. 2 is a sequence diagram of the first printing pattern. FIG. 3 is a schematic diagram showing the operation of the first printing pattern. In the "first printing pattern," after white printing is completed on the entire recording medium M by the first carriage 1A, color printing is performed on top of that by the second carriage 1B. In other words, in the first printing pattern, after printing on the entire recording medium M by the first carriage 1A is completed, printing on the entire recording medium M by the second carriage 1B is performed.

[0030] First, the controller 10 moves the sub-scanning carriage 50 to the print start position of the first carriage 1A, and then sends a print command to the first carriage 1A in step S11 of the sequence diagram in FIG.

[0031] The first carriage 1A performs white printing in response to receiving the print command (step S12). During white printing, the sub-scanning carriage 50 moves the recording medium M in the sub-scanning direction (toward the front of the device), while the first carriage 1A moves back and forth in the main scanning direction, ejecting ink onto the recording medium M. Then, when white printing is completed over the entire surface of the recording medium M, information indicating that printing is complete is sent to the controller 10 (step S13).

[0032] Figure 3(A) shows the state in which white printing is performed by the first carriage 1A while the sub-scanning carriage 50 moves the recording medium M toward the front of the device (positive Y direction), as indicated by arrow A in the figure, and white printing P1 is completed on the recording medium M in step S13.

[0033] 2, when the controller 10 receives information that printing is complete from the first carriage 1A, as shown in FIG. 3(B), it moves the sub-scanning carriage 50 toward the rear of the device (negative Y direction) as indicated by arrow B in the figure, and moves the recording medium M to the print start position of the second carriage 1B. Then, in step S14 of the sequence diagram in FIG. 2, it sends a print command to the second carriage 1B.

[0034] The second carriage 1B performs color printing in response to receiving a print command (step S15). During color printing, the sub-scanning carriage 50 moves the recording medium M in the sub-scanning direction (toward the front of the device), while the second carriage 1B moves back and forth in the main scanning direction, ejecting ink onto the recording medium M. Then, when color printing is completed over the entire surface of the recording medium M, information indicating that printing is complete is sent to the controller 10 (step S16), and printing on the recording medium M is completed. The recording medium M on which printing has been completed is sent to the front end of the device by the sub-scanning carriage 50.

[0035] Figure 3(C) shows the process in which color printing is performed by the second carriage 1B while the sub-scanning carriage 50 moves the recording medium M toward the front of the device (positive Y direction), as indicated by arrow C in the figure, and color printing P2 is superimposed on white printing P1 on the recording medium M.

[0036] Next, the second printing pattern will be described with reference to FIGS. 4 and 5. FIG. 4 is a sequence diagram of the second printing pattern. FIG. 5 is a schematic diagram showing the operation of the second printing pattern. In the "second printing pattern," while the first carriage 1A is printing white, the second carriage 1B simultaneously performs color printing on the portion of the recording medium M on which printing by the first carriage 1A has been completed. In other words, in the second printing pattern, after printing on a portion of the recording medium M by the first carriage 1A is completed, the second carriage 1B prints on this portion of the recording medium M, and the first carriage 1A and second carriage 1B are driven simultaneously to perform printing. In the second printing pattern, printing operations by the two carriages 1A and 1B can be performed simultaneously, thereby speeding up printing.

[0037] First, the controller 10 moves the sub-scanning carriage 50 to the print start position of the first carriage 1A, and then in step S21 of the sequence diagram in FIG.

[0038] The first carriage 1A performs white printing in response to receiving the print command (step S22). During white printing, the sub-scanning carriage 50 moves the recording medium M in the sub-scanning direction (toward the front of the device), while the first carriage 1A moves back and forth in the main scanning direction, ejecting ink onto the recording medium M. Then, when white printing is completed over the entire surface of the recording medium M, information indicating that printing is complete is sent to the controller 10 (step S25).

[0039] Meanwhile, when the front portion of the recording medium M on which white printing has been performed by the first carriage 1A reaches the printing start position of the second carriage 1B before the white printing by the first carriage 1A is completed, the controller 10 sends a print command to the second carriage 1B (step S23).

[0040] Figure 5(A) shows the state in step S23 in which white printing is performed by the first carriage 1A while the sub-scanning carriage 50 moves the recording medium M toward the front of the device (positive Y direction), as indicated by arrow D in the figure, and during this process, the front portion of the recording medium M on which white printing P1 has been performed reaches the printing start position of the second carriage 1B.

[0041] The second carriage 1B performs color printing in response to receiving a print command (step S24). During color printing, the sub-scanning carriage 50 moves the recording medium M in the sub-scanning direction (toward the front of the device), while the second carriage 1B moves back and forth in the main scanning direction, ejecting ink onto the recording medium M. Then, when color printing is completed over the entire surface of the recording medium M, information indicating that printing is complete is sent to the controller 10 (step S26), and printing on the recording medium M is completed.

[0042] Figure 5(B) shows the process of step S24 in which white printing is performed by the first carriage 1A while the sub-scanning carriage 50 moves the recording medium M toward the front of the device (positive Y direction), as indicated by arrow E in the figure, and color printing is performed in parallel by the second carriage 1B on the part of the recording medium M where white printing P1 has been completed, and color printing P2 is superimposed on the white printing P1.

[0043] Thus, compared to the first printing pattern, the second printing pattern has the advantage of being able to print simultaneously using two carriages 1A and 1B, thereby speeding up printing. However, with the second printing pattern, the white print P1 (white ink) ejected onto the recording medium M tends to take less time to dry between the end of white printing and the start of color printing, which can result in lower image quality than with the first printing pattern. This point will be explained with reference to Figures 6 and 7.

[0044] Fig. 6 is a schematic diagram showing an example of a printing sequence when the printing portion by the first carriage 1A is relatively large. Fig. 6(A) shows an example of the arrangement of each color of the entire image printed on the recording medium M. Fig. 6(B) is a sequence diagram showing the procedure for forming the image shown in Fig. 6(A) on the recording medium M. In Fig. 6(B), the front side (positive Y direction) in the transport direction of the recording medium M is illustrated as the right direction, and the procedure is illustrated as progressing from top to bottom, with eight steps required in this example.

[0045] As shown in Figure 6(A), in this example, white printing P1 and color printing P2 are performed in four areas R1, R2, R3, and R4 on the recording medium M, respectively, illustrating a case in which the number of areas is relatively larger than in the example of Figure 7 described below.

[0046] When printing the image shown in Fig. 6(A), for example, in the first stage as shown in Fig. 6(B), the sub-scanning carriage 50 moves the recording medium M so that the frontmost region R1 of the recording medium M is positioned at the printing position of the first carriage 1A. Then, the first carriage 1A performs white printing P1 in the frontmost region R1 of the recording medium M.

[0047] In the second stage, as shown by the arrow F1 in the figure, the sub-scanning carriage 50 moves the recording medium M forward in the transport direction, and the printing position of the first carriage 1A is the second region R2 from the front of the recording medium M. Then, the first carriage 1A performs white printing P1 in the second region R2 from the front of the recording medium M.

[0048] In the third stage, as shown by arrow F2 in the figure, the sub-scanning carriage 50 moves the recording medium M further forward in the transport direction, and the printing position of the first carriage 1A is positioned at the third region R3 from the front of the recording medium M. Then, the first carriage 1A performs white printing P1 in the third region R3 from the front of the recording medium M.

[0049] In the fourth stage, as shown by arrow F3 in the figure, the sub-scanning carriage 50 moves the recording medium M further forward in the transport direction, and the frontmost region R1 of the recording medium M is positioned at the printing position of the second carriage 1B. White printing P1 was performed in this region R1 in the first stage. Then, color printing P2 is performed on top of the white printing P1 in the frontmost region R1 of the recording medium M by the second carriage 1B.

[0050] Thereafter, white printing P1 and color printing P2 are sequentially performed on predetermined areas R2, R3, and R4 on the recording medium M, and all printing is completed at the eighth stage.

[0051] In the example of Figure 6, it is in the fourth stage that color printing P2 is performed in the frontmost area R1 where white printing P1 was first performed in the first stage.As shown by arrows F1, F2, and F3 in Figure 6(B), the amount of movement in each stage is relatively small, so there is a waiting time of three stages after white printing P1 is performed in the same area R1 before color printing P2 is performed, and the drying time of the white printing P1 is relatively long.

[0052] Figure 7 is a schematic diagram showing an example of a printing sequence when the portion printed by the first carriage 1A is relatively small. Figure 7(A), like Figure 6(A), shows an example of the arrangement of each color of the entire image printed on the recording medium M. Figure 7(B), like Figure 6(B), is a sequence diagram showing the procedure for forming the image shown in Figure 6(A) on the recording medium M, which in this example requires four steps.

[0053] As shown in Figure 7(A), in this example, white printing and color printing are performed in two areas on the recording medium M, the frontmost area R1 in the transport direction and the rearmost area R4, respectively, and the number of areas where printing is performed is relatively smaller than in the example of Figure 6. The distance between the two areas R1 and R4 is also relatively wide.

[0054] 7(A), in the first stage, as shown in FIG. 7(B), the sub-scanning carriage 50 moves the recording medium M so that the frontmost region R1 of the recording medium M is positioned at the printing position of the first carriage 1A. Then, the first carriage 1A performs white printing P1 in the frontmost region R1 of the recording medium M.

[0055] In the second stage, as shown by arrow G in the figure, the sub-scanning carriage 50 moves the recording medium M forward in the transport direction, and the frontmost region R1 of the recording medium M is positioned at the printing position of the second carriage 1B. White printing P1 was performed in this region R1 in the first stage. Then, color printing P2 is performed on top of the white printing P1 in the frontmost region R1 of the recording medium M by the second carriage 1B.

[0056] In the third stage, the recording medium M is moved further forward in the transport direction by the sub-scanning carriage 50, and the recording medium M is moved so that the rearmost region R4 of the recording medium M is positioned at the printing position of the first carriage 1A. Then, white printing P1 is performed on the rearmost region R4 of the recording medium M by the first carriage 1A.

[0057] In the fourth stage, as shown by arrow G in the figure, the sub-scanning carriage 50 moves the recording medium M further forward in the transport direction, and the rearmost region R4 of the recording medium M is positioned at the printing position of the second carriage 1B. White printing P1 was performed in this region R4 in the third stage. Then, color printing P2 is performed on top of the white printing P1 in the rearmost region R4 of the recording medium M by the second carriage 1B. When the fourth stage is complete, all printing is complete.

[0058] In the example of Fig. 7, in the second stage, color printing P2 is performed in the frontmost region R1 where white printing P1 was performed in the first stage, and in the fourth stage, color printing P2 is performed in the rearmost region R4 where white printing P1 was performed in the third stage, and the amount of movement in each stage is relatively large, as shown by arrow G in Fig. 7. For this reason, there is only one stage's worth of waiting time until color printing P2 is performed after white printing P1 is performed in the same region R1, and the drying time of the white printing P1 tends to be relatively short.

[0059] Furthermore, as shown in Figure 7, in the image printed on the recording medium M, the greater the relative distance between the areas R1 and R4 where the first carriage 1A performs the white printing P1, the greater the amount of movement of the recording medium M between each stage of the printing sequence, which tends to further shorten the waiting time until the color printing P2 is performed after the white printing P1 is performed in the same area.

[0060] 2 and 3, after the first carriage 1A has completed white printing P1 over the entire area of ​​the recording medium M, the recording medium M is moved again upstream in the transport direction by the sub-scanning carriage 50 from a state in which the rearmost part of the recording medium M is positioned at the printing position of the first carriage 1A, and the frontmost part of the recording medium M is positioned at the printing position of the second carriage 1B. In other words, when focusing on the frontmost part of the recording medium M, the first printing pattern ensures that drying time is secured between white printing P1 and color printing P2, for one round trip of the entire length of the recording medium M in the transport direction.

[0061] As such, with the second print pattern, the white ink drying time between white printing and the start of color printing tends to be shorter than with the first print pattern, so if color printing P2 is performed before the white printing P1 has had enough time to dry, the image quality may be worse than with the first print pattern due to reasons such as the white ink and colored inks mixing. This embodiment aims to speed up printing by implementing the second print pattern while preventing this problem of image quality degradation.

[0062] For this reason, in this embodiment, the controller 10 calculates the drying time of the white printed ink on the recording medium M after white printing by the first carriage 1A positioned upstream in the transport direction, and performs printing pattern selection control to determine whether or not the second printing pattern can be executed based on the calculated drying time.

[0063] <Print pattern selection control> The print pattern control performed by the controller 10 will be described with reference to Fig. 8. Fig. 8 is a flowchart of print pattern selection control in this embodiment.

[0064] In step S31, image data is acquired. The controller 10 can acquire data of an image to be printed on the recording medium M using the image forming apparatus 100 from an external device, such as a PC, that is communicably connected to the image forming apparatus 100.

[0065] In step S32, a printing sequence is calculated based on the image data acquired in step S31. The printing sequence is a subdivision of the printing process performed by each carriage 1A, 1B to form an image on recording medium M based on image data, as shown in Fig. 6(B) and Fig. 7(B).

[0066] In step S33, the drying time for the white print by the first carriage 1A is calculated based on the printing sequence acquired in step S32. For example, the controller 10 calculates the drying time based on the amount of liquid (white ink) ejected onto the recording medium M by the first carriage 1A from among the images to be printed on the recording medium M. More specifically, the controller 10 performs calculations so that the greater the ink ejection amount of the white print P1, the longer the required drying time. Here, "a large amount of ink ejection" can also be expressed as a large number of interlaces, i.e., a large number of scans for the same location. The ink ejection amount varies depending on factors such as the printing rate of the image in the corresponding area. The controller 10 also calculates the required drying time for each area divided in the sub-scanning direction of the recording medium M, such as areas R1, R2, R3, and R4 shown in FIGS. 6 and 7.

[0067] In step S34, the time required for the recording medium M to move to the second carriage 1B after white printing by the first carriage 1A in the second print pattern is calculated based on the print sequence acquired in step S32. For example, if the image to be printed on the recording medium M contains blank areas where no printing is performed by the first carriage 1A, the controller 10 can calculate a shorter movement time depending on the size of the blank areas. For example, as illustrated in FIG. 7, if there is a blank area where no printing is performed between the first printed area R1 and the next printed area R4 along the transport direction, the first carriage 1A will not print in the blank area. Therefore, as shown by arrow G in FIG. 7B, the area R1 where printing by the first carriage 1A has been completed can be immediately moved to the printing position of the second carriage 1B. Therefore, the controller 10 performs calculations to shorten the movement time the larger the blank areas in the image data. Furthermore, the controller 10 calculates the movement time for each area divided in the sub-scanning direction of the recording medium M, such as areas R1, R2, R3, and R4 shown in FIGS.

[0068] In step S35, it is determined whether the drying time calculated in step S33 is equal to or less than the movement time calculated in step S34. Controller 10 compares the drying time with the movement time for each region divided in the sub-scanning direction of recording medium M, such as regions R1, R2, R3, and R4 shown in Figures 6 and 7, and can determine that the condition of step S35 is met if the drying time is equal to or less than the movement time in all regions.

[0069] If the drying time is less than or equal to the movement time (YES in step S35), it is determined that the second printing pattern will also provide sufficient drying time for the white ink before color printing, and the process proceeds to step S36, where printing is carried out using the second printing pattern.

[0070] On the other hand, if the drying time is less than the movement time (NO in step S35), it is determined that the second printing pattern does not allow sufficient time for the white ink to dry before color printing, and the process proceeds to step S37, where printing is carried out using the first printing pattern.

[0071] The effects of the image forming apparatus 100 according to this embodiment will be described. The image forming apparatus 100 according to this embodiment includes a sub-scanning carriage 50 that moves the recording medium M along the transport direction, a first carriage 1A and a second carriage 1B that are arranged in parallel along the transport direction and each capable of printing on the recording medium M along a main scanning direction perpendicular to the transport direction, and a controller 10 that controls the operation of the first carriage 1A, the second carriage 1B, and the sub-scanning carriage 50. The controller 10 can execute a first print pattern in which, after the first carriage 1A has completed printing on the entire recording medium M, the second carriage 1B prints on the entire recording medium M, and a second print pattern in which, after the first carriage 1A has completed printing on a portion of the recording medium M (such as the region R1 shown in FIGS. 6 and 7 ), the second carriage 1B prints on the portion R1 of the recording medium M, and the first carriage 1A and the second carriage 1B are driven simultaneously to perform printing. The controller 10 calculates the drying time of the liquid ejected onto the recording medium M after printing by the first carriage 1A, and determines whether or not the second print pattern can be executed based on the drying time.

[0072] With this configuration, the drying time of the liquid ejected onto the recording medium M after printing by the first carriage 1A is calculated, and whether or not to execute the second print pattern is determined based on the drying time. Therefore, if the drying time is insufficient, control can be performed so that the second print pattern is not executed, thereby suppressing deterioration in the image quality of the printed image. On the other hand, if the drying time is sufficient, the second print pattern is executed, thereby speeding up printing. In this way, this embodiment can achieve both high-speed printing in the image forming apparatus 100 and suppression of deterioration in the image quality of the printed image.

[0073] Furthermore, in the image forming apparatus 100 of this embodiment, the controller 10 first calculates the drying time of the ink ejected onto a portion of the recording medium M (such as the region R1 shown in FIGS. 6 and 7) after printing on this region R1 by the first carriage 1A is completed in the case of the second print pattern. Next, it calculates the movement time of the recording medium M by the sub-scanning carriage 50 after printing on the portion R1 of the recording medium M by the first carriage 1A is completed until printing on the portion R1 of the recording medium M by the second carriage 1B. Then, if the drying time is less than or equal to the movement time, the second print pattern is executed, and otherwise the first print pattern is executed.

[0074] This configuration compares the drying time of the white print P1 on a portion of the recording medium M (such as region R1) by the first carriage 1A with the travel time for this region R1 to move to the printing position of the second carriage 1B. If the drying time is less than or equal to the travel time, it is determined that the white print P1 in that area has had sufficient time to dry, and the second print pattern can be executed. This makes it possible to accurately determine whether the white print P1 has had sufficient time to dry, thereby preventing situations in which the first execution pattern is selected even when the second print pattern could otherwise be executed, and allows the frequency of execution of the second execution pattern to be appropriate. As a result, a good balance can be achieved between high-speed printing and reduced degradation in the quality of printed images.

[0075] In addition, in the image forming apparatus 100 of this embodiment, when there is a blank area in the image to be printed on the recording medium M where printing is not performed by the first carriage 1A, the controller 10 calculates the movement time by shortening it according to the amount of the blank area.

[0076] This configuration makes it possible to accurately calculate the travel time according to the content of the printed image, and by using this travel time information, it is possible to determine with even greater accuracy whether the white print P1 has had sufficient drying time according to the content of the printed image.

[0077] Furthermore, in the image forming apparatus 100 of this embodiment, the controller 10 calculates the drying time based on the amount of liquid ejected onto the recording medium M by the first carriage 1A in the image to be printed on the recording medium M.

[0078] This configuration makes it possible to accurately calculate the drying time according to the content of the printed image, and by using this drying time information, it is possible to determine with even greater accuracy whether the white print P1 has had sufficient drying time according to the content of the printed image.

[0079] The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Design modifications to these specific examples made by a person skilled in the art as appropriate are also included within the scope of the present disclosure as long as they comprise the features of the present disclosure. The elements of the above-described specific examples, as well as their arrangement, conditions, shape, etc., are not limited to those exemplified and can be modified as appropriate. The elements of the above-described specific examples can be combined in various ways as appropriate, as long as no technical contradictions arise. [Explanation of symbols]

[0080] 1 carriage 1A First carriage 1B 2nd carriage 6 Liquid ejection head 10 Controllers 50 Sub-scanning carriage 100 Liquid dispensing device M Recording medium R1, R2, R3, R4 area (part of recording medium) [Prior art documents] [Patent documents]

[0081] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-341168

Claims

1. a sub-scanning carriage that moves the recording medium along the transport direction; a first carriage and a second carriage, each capable of printing on the recording medium along a main scanning direction perpendicular to the transport direction, the first carriage and the second carriage arranged in parallel along the transport direction; a controller that controls the operations of the first carriage, the second carriage, and the sub-scanning carriage; Equipped with The controller a first print pattern for printing the entire recording medium by the second carriage after the first carriage has completed printing the entire recording medium; a second printing pattern in which, after printing on a portion of the recording medium by the first carriage is completed, printing on the portion of the recording medium by the second carriage is performed, and the first carriage and the second carriage are simultaneously driven to perform printing; calculating a drying time of the liquid ejected onto the recording medium after printing by the first carriage, and determining whether or not the second print pattern can be executed based on the drying time; Image forming device.

2. the controller calculates the drying time of the liquid ejected onto the portion of the recording medium after printing on the portion by the first carriage is completed in the case of the second print pattern; calculating a time for moving the recording medium by the sub-scanning carriage after the first carriage has completed printing on the portion of the recording medium until the second carriage starts printing on the portion of the recording medium; If the drying time is equal to or less than the moving time, the second printing pattern is executed, and otherwise the first printing pattern is executed. The image forming apparatus according to claim 1 .

3. when there is a blank portion in the image to be printed on the recording medium where printing is not performed by the first carriage, the controller reduces the movement time in accordance with the amount of the blank portion. The image forming apparatus according to claim 2 .

4. the controller calculates the drying time based on an amount of liquid ejected onto the recording medium by the first carriage in the image to be printed on the recording medium; The image forming apparatus according to any one of claims 1 to 3.

Images