JP2016055632A - Image forming device and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device that can perform correctly printing by preventing a time lag between scanning of a recording head and conveyance of recording media.SOLUTION: The image forming device comprises: conveying means that conveys recording media; a recording head that performs reciprocating scanning in a direction orthogonal to a conveying direction of the recording media and forms images on the recording media in a state where the recording media are being conveyed by the conveying means; receiving means that receives scanned image data while the recording head is waiting at a non-printing region; and control means that controls distances of the recording media conveyed by the conveying means for a period of time during which the recording head is waiting at the non-printing region, on the basis of reception time of the scanned image data to be determined from communication speed of the receiving means.SELECTED DRAWING: Figure 7

Description

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

  2. Description of the Related Art An ink jet recording apparatus that forms an image by ejecting ink from a recording head that reciprocates in a main scanning direction orthogonal to the sub scanning direction is widely used on a recording medium conveyed in the sub scanning direction. In a conventional inkjet recording apparatus, recording is performed by repeating the operation of scanning the recording head in a state where conveyance of the recording medium is stopped to form an image, and conveying the recording medium by a predetermined amount while the recording head is decelerated or stopped. An image is formed on a medium.

  In such a configuration in which an image is formed by reciprocating scanning of a recording head while intermittently transporting a recording medium, operations such as transport of the recording medium and scanning of the recording head, particularly mechanical impact sound generated at the start and stop of the operation. Etc. may be noise.

  In view of this, a printer has been proposed in which the recording medium is always transported at a constant speed without stopping during image formation and the acceleration / deceleration time in the reciprocating scanning of the recording head is shortened to reduce operation noise during image formation. (For example, refer to Patent Document 1).

  However, in the method in which the recording medium is continuously conveyed at a constant speed during image formation, for example, when reception of scanned image data is delayed during image formation, a deviation occurs between the image forming operation and the conveyance of the recording medium, so It may be formed.

  The present invention has been made in view of the above, and an object of the present invention is to provide an image forming apparatus capable of performing accurate printing by preventing a deviation between scanning of a recording head and conveyance of a recording medium.

  According to an image forming apparatus of one aspect of the present invention, a reciprocating scan is performed in a direction perpendicular to the conveyance direction of the recording medium while the recording medium is conveyed by the conveyance unit. A recording head for forming an image on the recording medium; a receiving means for receiving scanned image data while the recording head is waiting in a non-printing area; and receiving the scanned image data obtained from a communication speed of the receiving means Control means for controlling a transport distance of the recording medium by the transport means while the recording head stands by in the non-printing area based on time.

  According to the embodiment of the present invention, there is provided an image forming apparatus capable of performing accurate printing by preventing a deviation between scanning of a recording head and conveyance of a recording medium.

1 is a schematic view illustrating the configuration of an ink jet recording apparatus according to a first embodiment. 1 is a block diagram illustrating the configuration of an ink jet recording apparatus according to a first embodiment. FIG. 5 is a diagram illustrating a printing operation of the ink jet recording apparatus according to the first embodiment. FIG. 6 is a diagram illustrating a carriage scanning speed and a sheet conveyance speed in the first embodiment. It is a figure which illustrates a mode that an image is formed on a paper in 1st Embodiment. FIG. 5 is a diagram illustrating a state where an image is formed on a sheet in the first embodiment. FIG. 3 is a diagram illustrating a flowchart of print processing according to the first embodiment. It is a figure which illustrates the flowchart of the reception time calculation process in 1st Embodiment. It is a figure which illustrates the flowchart of the conveyance control process 1 in 1st Embodiment. It is a figure which illustrates the control result of the conveyance speed by the conveyance control process 1 in 1st Embodiment. It is a figure which illustrates the flowchart of the conveyance control process 2 in 1st Embodiment. It is a figure which illustrates the control result of the conveyance speed by the conveyance control process 2 in 1st Embodiment. It is a figure which illustrates the flowchart of the printing process in 2nd Embodiment. It is a figure which illustrates the flowchart of the maintenance process in 2nd Embodiment. It is a figure which illustrates the flowchart of the conveyance control process in 2nd Embodiment. It is a figure which illustrates the state which the color nonuniformity generate | occur | produced. It is a figure which illustrates the flowchart of the printing process in 3rd Embodiment. It is a figure which illustrates the printing process ((alpha) = 1) in 3rd Embodiment. It is a figure which illustrates the printing process ((alpha) = 3) in 3rd Embodiment.

  Hereinafter, embodiments for carrying out the invention will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant description may be omitted.

[First embodiment]
<Configuration of inkjet recording apparatus>
A configuration of the inkjet recording apparatus 1 according to the first embodiment will be described. In the following, a case where the ink jet recording apparatus 1 forms an image on a sheet as a recording medium is illustrated, but the recording medium is not limited to a sheet, and may be, for example, a film or a cloth.

  FIG. 1 is a schematic view illustrating the configuration of an inkjet recording apparatus 1 according to the embodiment.

  As shown in FIG. 1, the inkjet recording apparatus 1 according to the embodiment includes a carriage 100 on which a recording head 118 that forms an image by ejecting ink onto a conveyed paper 108 is mounted.

  The carriage 100 is held on the slide rail 104 so as to be movable in the main scanning direction (left and right direction in FIG. 1). Further, a part of the timing belt 102 that is stretched between a driving pulley 106 and a driven pulley 107 provided along the slide rail 104 and rotates by being driven by the driving pulley 106 is fixed to the carriage 100. ing.

  When the main scanning motor 105 connected to the driving pulley 106 is driven, the timing belt 102 rotates following the driving pulley 106, and the carriage 100 fixed to the timing belt 102 performs main scanning along the slide rail 104. Move in the direction.

  The carriage 100 is equipped with a main scanning encoder sensor 117 used for position detection in the main scanning direction. The main scanning encoder sensor 117 moves in the main scanning direction together with the carriage 100 and detects a plurality of slits provided in the encoder scale 103. Based on the detection result of the slit of the encoder scale 103 by the main scanning encoder sensor 117, the position of the carriage 100 in the main scanning direction is obtained.

  The recording head 118 mounted on the carriage 100 includes four liquid droplet ejection heads that eject ink droplets of colors such as yellow, cyan, magenta, and black. The recording head 118 is held by the carriage 100 so that the nozzle surface on which a plurality of ink discharge ports (nozzles) of each droplet discharge head are arranged faces the surface of the paper 108 being conveyed. Note that the number, color, and the like of the droplet discharge heads provided in the recording head 118 are not limited to the configuration exemplified in this embodiment.

  The recording head 118 discharges ink droplets from each droplet discharge head while reciprocating in the main scanning direction together with the carriage 100 with the above-described configuration, and is a print area of the paper 108 that is conveyed in the sub-scanning direction orthogonal to the main scanning direction. An image is formed on.

  The paper 108 is transported in the sub-scanning direction by the transport belt 101. The conveyor belt 101 is an endless belt that is stretched between the conveyor roller 109 and the tension roller 110 and rotates in the sub-scanning direction. The conveyance belt 101 is charged by a charging roller (not shown), electrostatically attracts the paper 108 and conveys it in the sub-scanning direction.

  A timing belt 114 is stretched between a transport roller pulley 113 provided at one end of the rotation shaft of the transport roller 109 and a transport drive pulley 112 connected to the sub-scanning motor 111. When the sub-scanning motor 111 is rotationally driven, the transport roller 109 rotates through the transport drive pulley 112, the timing belt 114, and the transport roller pulley 113, and the transport belt 101 rotates following the transport roller 109.

  In addition, an encoder wheel 115 in which a plurality of slits are formed at equal intervals in the circumferential direction is provided at one end of the rotation shaft of the transport roller 109. Further, a sub-scanning encoder sensor 116 that detects a slit of the encoder wheel 115 that rotates together with the conveying roller 109 is fixed. From the rotation amount of the conveyance belt 101 obtained based on the detection result by the sub scanning encoder sensor 116, the conveyance position of the paper 108 in the sub scanning direction is obtained.

  The transport belt 101, the sub-scanning motor 111, and the like are examples of transport means, transport the paper 108 supplied from a paper feed tray (not shown), and discharge the paper 108 on which an image is formed to the outside of the apparatus.

  Further, a maintenance unit 91 for maintaining and recovering the nozzle state of the recording head 118 is provided in a non-printing area on one side of the carriage 100 in the main scanning direction. The maintenance unit 91 includes a cap 92 that covers the nozzle surface of the recording head 118, an empty discharge receiver 93 that receives liquid discharged when the recording head 118 performs empty discharge, and a wiper blade 94 that wipes off ink adhering to the nozzle surface of the recording head 118. Have

  When the carriage 100 is not in use, it moves to the maintenance unit 91 and stands by, and the nozzle surface of the recording head 118 is covered with the cap 92, so that ejection failure due to drying of the nozzle surface is prevented. Further, the carriage 100 moves to the maintenance unit 91 at predetermined maintenance time intervals, and various maintenance processes such as idle ejection of the recording head 118 and wiping of the nozzle surface of the recording head 118 are executed.

  FIG. 2 is a block diagram illustrating the configuration of the inkjet recording apparatus 1 according to the embodiment.

  As shown in FIG. 2, the inkjet recording apparatus 1 includes a control unit 120, a head driver 130, a carriage 100, a main scanning motor 105, a sub scanning motor 111, a conveyance belt 101, a sub scanning encoder sensor 116, and an operation panel 140. .

  The control unit 120 is an example of a control unit, and includes a CPU 121, a ROM 122, a RAM 123, an NVRAM 124, an ASIC 125, and an I / O 126, and controls each unit of the inkjet recording apparatus 1.

  The ROM 122 stores various programs and data used by the programs. The RAM 123 is used as a storage area for loading a program, a work area for the loaded program, and the like. The CPU 121 realizes various functions by processing a program loaded in the RAM 123.

  The ASIC 125 processes input / output signals for controlling various types of signal processing, rearrangement, and the like for image data input to the inkjet recording apparatus 1 and other control of the entire apparatus. The I / O 126 inputs and outputs signals between the main scanning encoder sensor 117 and the sub scanning encoder sensor 116. The host I / F 127 transmits and receives image data and various signals to and from an external device such as a PC connected to the inkjet recording apparatus 1 by wire or wirelessly.

  The control unit 120 performs image processing and the like on the image data input to the host I / F 127 and outputs the image data and drive waveform subjected to the image processing to the head driver 130. The head driver 130 causes the recording head 118 to eject ink by selectively applying a driving pulse constituting the input driving waveform to the pressure generating means of the recording head 118.

  The main scanning motor 105 is driven to rotate under the control of the control unit 120 to move the carriage 100 together with the recording head 118 in the main scanning direction. The main scanning encoder sensor 117 moves with the carriage 100 in the main scanning direction, detects the slit of the encoder scale 103, and outputs a detection signal to the I / O 126 of the control unit 120.

  The sub-scanning motor 111 is driven to rotate under the control of the control unit 120, thereby rotating the transport belt 101 and transporting the paper 108. The sub-scanning encoder sensor 116 detects the slit of the encoder wheel 115 and outputs a detection signal to the I / O 126 of the control unit 120.

  The operation panel 140 is hardware including input means such as buttons for accepting input from a user, an operation screen such as a liquid crystal panel having a touch panel function, and the like, and is connected to the control unit 120.

  The inkjet recording apparatus 1 has the above-described configuration, and the control unit 120 controls the scanning of the carriage 100 on which the recording head 118 is mounted, the conveyance of the paper 108, and the like to print the input image data on the paper 108. Output.

<Printing action>
Next, a printing operation in the inkjet recording apparatus 1 will be described. FIG. 3 is a diagram for explaining a printing operation in the inkjet recording apparatus 1.

  In the inkjet recording apparatus 1, the paper 108 is transported in the sub-scanning direction (upward in FIG. 3) at a transport speed controlled by the control unit 120. The carriage 100 reciprocates between a position L and a position R which are reverse positions provided in a non-printing area of the paper 108 in the main scanning direction, and the recording head 118 discharges ink droplets to print the paper 108. An image is formed in the region 108a.

  For example, when the carriage 100 scans to the position L (R), the carriage 100 temporarily stops. After the next scanned image data is input to the host I / F 127 of the control unit 120, the carriage 100 scans to the position R (L) and the recording head 118 moves. An image is formed based on the scanned image data.

  Here, in the inkjet recording apparatus 1, the paper 108 is continuously conveyed in the sub-scanning direction without stopping during scanning of the carriage 100. Therefore, as shown in FIG. 3, the carriage 100 moves in an oblique direction (a direction inclined to both the transport direction of the paper 108 and the direction orthogonal to the transport direction) with respect to the transported paper 108. It will be.

  The sheet 108 is less than ½ of the width W in the sub-scanning direction of the nozzle row provided in the recording head 118 while the carriage 100 scans from the position L (R) to the position R (L) in the main scanning direction. The distance D is conveyed. Thus, the carriage 100 reciprocates in the main scanning direction with respect to the paper 108 that is continuously conveyed in the sub-scanning direction, whereby the recording head 118 scans the print area 108a of the paper 108 without gaps to form an image.

  In the inkjet recording apparatus 1, the paper 108 is continuously transported without stopping even during the scanning of the carriage 100 in this manner, so that, for example, the operation of the transport belt 101 and the like start and Mechanical noise generated when stopping is reduced.

  FIG. 4 is a diagram illustrating the scanning speed of the carriage 100 and the conveyance speed of the paper 108 in the first embodiment. 4 is a graph illustrating the scanning speed of the carriage 100. The scanning speed in the A direction shown in FIG. 3 is positive (+), and the scanning speed in the B direction is negative (−). 4 is a graph illustrating the conveyance speed of the paper 108.

  As shown in the upper graph of FIG. 4, when scanning image data is input, the carriage 100 starts scanning from position L to position R at time T1, for example, and reaches position R at time T2. Further, as shown in the lower graph of FIG. 4, the sheet 108 is conveyed at the conveyance speed Vp1 in the sub-scanning direction.

  In this way, when the carriage 100 scans the paper 108 conveyed in the sub-scanning direction from the position L to the position R in the main scanning direction, as shown in FIG. An image is formed in a region 119a1 of the region 108a.

  Next, as shown in FIG. 4, when the next scan image data is input until the carriage 100 is temporarily stopped at the position R and until time T3, the carriage 100 is reversed and scanned toward the position L, as shown in FIG. The position L is reached at time T4. Further, while the carriage 100 is temporarily stopped from the time T2 to the time T3 and while the carriage 100 is scanned from the time T3 to the time T4, the paper 108 is conveyed at the conveyance speed Vp1 in the sub-scanning direction.

  As described above, when the carriage 100 scans the paper 108 continuously conveyed in the sub-scanning direction from the position R to the position L in the main scanning direction, the recording head 118 passes as shown in FIG. An image is formed in the area 119b1 of the print area 108a.

  Here, as shown in FIG. 5B, during the standby time Ts from the time T2 to the time T3 when the carriage 100 and the recording head 118 are reversed in the non-printing region, the paper 108 is transported at the transport speed Vp1 in the sub-scanning direction. It is transported and displaced by a distance A (= Vp1 × Ts). By conveying the paper 108 while the carriage 100 is reversed, the image forming position of the recording head 118 is also displaced by the distance A.

  Subsequently, as shown in FIG. 4, when the next scan image data is input from time T4 to time T5 after the carriage 100 is temporarily stopped at the position L, the carriage 100 is reversed and scanned toward the position R. Then, it reaches position R at time T6 and pauses until time T7. When the next scanned image data is input between time T6 and time T7, the carriage 100 is reversed at the position R and performs scanning toward the position L, and reaches the position L at time T8. While the carriage 100 is reciprocatingly scanned, the paper 108 is continuously transported at the transport speed Vp1 in the sub-scanning direction.

  As described above, when the carriage 100 reciprocates, an image is formed on the paper 108 in the order of the region 119a1, the region 119b1, the region 119a2, the region 119b2,..., And the print region 108a. An image is formed on the entire surface.

  Here, for example, if a delay occurs in the reception of the next scan image data while the carriage 100 is reversed at the position L or the position R, the carriage 100 exceeds the predetermined waiting time until the reception of the scan image data is completed. Or it will wait at the position R. In such a case, if the paper 108 is continuously conveyed at the constant conveyance speed Vp1, the distance A shown in FIGS. 5B and 6 increases, and the scanning position of the recording head 118 is shifted, and the paper 108 is displaced. There may be a region where no image is printed in the print region 108a.

  Therefore, in the inkjet recording apparatus 1 according to the present embodiment, when the reception of scanned image data is delayed due to the printing process described below, the conveyance speed of the paper 108 is changed so that the entire surface of the print area 108a is changed. Printing can be performed.

<Print processing>
FIG. 7 is a diagram illustrating a flowchart of the printing process according to the first embodiment.

  As shown in FIG. 7, when printing is started in the inkjet recording apparatus 1, the paper 108 is started to be transported at the transport speed Vp1 in step S101. In step S <b> 102, the recording head 118 scans in the main scanning direction together with the carriage 100 to form an image on the paper 108.

  When the carriage 100 scans in one direction in the main scanning direction and stops at the position L or R shown in FIG. 3 (step S103: YES), and the printing is continuously executed (step S104: YES), the step is performed. In S105, reception time calculation processing is executed.

(Reception time calculation process)
FIG. 8 is a diagram illustrating a flowchart of reception time calculation processing in the first embodiment.

  In the reception time calculation process, first, in step S201, the host I / F 127 of the control unit 120 receives the size Dt of the scanned image data from, for example, a printer driver of a PC connected to the inkjet recording apparatus 1. Next, in step S202, the host I / F 127 of the control unit 120 similarly receives communication speed measurement data whose data size Ds is known in advance from the printer driver of the PC.

  In step S203, the control unit 120 determines the communication speed Vd between the inkjet recording apparatus 1 and the PC connected to the inkjet recording apparatus 1 from the reception time Tt of the communication speed measurement data based on the following equation (1). To calculate.

Vd = Ds / Tt (1)
Subsequently, in step S204, the control unit 120 calculates a time Td required for receiving the scanned image data based on the following formula (2) based on the scanned image data size Dt and the communication speed Vd.

Td = Dt / Vd (2)
As described above, in the reception time calculation process, the control unit 120 calculates the reception time of the scanned image data.

  Returning to the flowchart of FIG. 7, when the reception time Td of the scanned image data is obtained by the reception time calculation process in step S105, the control unit 120 executes the conveyance control process in step S106.

(Transport control process 1)
FIG. 9 is a diagram illustrating a flowchart of the conveyance control process 1 according to the first embodiment.

  In the transport control process 1, as shown in FIG. 9, first, in step S <b> 301, the control unit 120 receives the scanning image data reception time Td and the waiting time at the preset position L or R of the carriage 100. Compare with Ts.

  If the reception time Td is smaller than the waiting time Ts (step S301: YES), in step S302, the control unit 120 sets the conveyance speed of the paper 108 while the carriage 100 is reversed at the time of printing (of the carriage 100). Set to the same speed Vp1 as during scanning.

  When the reception time Td is equal to or longer than the waiting time Ts (step S301: NO), in step S303, the control unit 120 determines the conveyance speed of the paper 108 while the carriage 100 is reversed by the following equation (3). Set to Vp2 represented.

Vp2 = Vp1 × Ts / Td (3)
For example, as shown in FIG. 10, when the carriage 100 starts reciprocating scanning from time T11 and printing on the paper 108 being conveyed at the conveyance speed Vp1, for example, at time T16, the reception time Td of the scanned image data is predetermined. It is assumed that it becomes longer than the waiting time Ts.

  In this case, the carriage 100 waits at the position R from the time T16 until the time T17 when the reception time Td elapses and the reception of the scanned image data is completed, and the sheet 108 is conveyed at the conveyance speed represented by the above equation (3). Transported by Vp2.

  Here, the conveyance distance A of the paper 108 between the time T12 and the time T13 and between the time T14 and the time T15 is expressed by the following formula (4).

A = Vp1 × Ts (4)
Further, the conveyance distance A ′ of the paper 108 between the time T16 and the time T17 at which the reception of the scanned image data is delayed is expressed by the following equation (5).

A ′ = Vp2 × Td (5)
Here, the above equation (5) is expressed as follows using equation (3).

A ′ = (Vp1 × Ts / Td) × Td
= Vp1 * Ts = A
As described above, the conveyance distance A ′ of the paper 108 between the time T16 and the time T17 when the reception of the scanned image data is delayed is the paper 108 between the time T12 and the time T13 and between the time T14 and the time T15. Is equal to the transport distance A.

  Therefore, even when the reception time Td of the scanned image data is equal to or longer than the predetermined standby time Ts, the conveyance distance of the paper 108 while the carriage 100 and the recording head 118 are reversed is kept constant. An image can be accurately formed.

(Transport control process 2)
Further, the conveyance speed of the paper 108 while the carriage 100 is reversed may be controlled by the conveyance control process 2 described below.

  FIG. 11 is a diagram illustrating a flowchart of the conveyance control process 2 in the first embodiment.

  In the transport control process 2, as shown in FIG. 11, first, in step S311, the control unit 120 receives the scan image data reception time Td and the standby time at the preset position L or R of the carriage 100. Compare with Ts.

  If the reception time Td is smaller than the standby time Ts (step S311: YES), in step S312, the control unit 120 sets the conveyance speed of the paper 108 during the reversal of the carriage 100 at the time of printing (of the carriage 100). Set to the same speed Vp1 as during scanning.

  When the reception time Td is equal to or longer than the standby time Ts (step S311: NO), in step S313, the control unit 120 sets the conveyance speed of the paper 108 while the carriage 100 is reversed to Vp1, and the conveyance time. Is set to Ts.

  For example, as shown in FIG. 12, when the carriage 100 starts reciprocating scanning from time T21 and printing on the paper 108 being conveyed at the conveyance speed Vp1, for example, at time T26, the reception time Td of the scanned image data is predetermined. It is assumed that it becomes longer than the waiting time Ts.

  In this case, the carriage 100 stands by at the position R until the time T27 when the reception time Td elapses and the reception of the scanned image data is completed. At this time, the sheet 108 is continuously conveyed at the conveyance speed Vp1 from the time T26 until the standby time Ts elapses, and the conveyance is stopped when the standby time Ts elapses.

  With the above-described control, the conveyance distance A ′ of the paper 108 between the time T26 and the time T27 when reception of the scanned image data is delayed is the paper between the time T22 and the time T23 and between the time T24 and the time T25. It becomes equal to the conveyance distance A of 108.

  Therefore, even when the reception time Td of the scanned image data is equal to or longer than the predetermined standby time Ts, the conveyance distance of the paper 108 while the carriage 100 and the recording head 118 are reversed is kept constant. An image can be accurately formed.

  Note that, as long as the conveyance distance of the paper 108 during the reversal of the carriage 100 and the recording head 118 can be kept constant, it may be controlled to change both the conveyance speed and the conveyance time of the paper 108.

  Returning to the flowchart of FIG. 7, when the conveyance speed of the paper 108 is set by the conveyance control process in step S <b> 106, the paper 108 is conveyed at the set conveyance speed in a state where the carriage 100 is stopped in step S <b> 107. .

  In step S108, when the reception time Td of the scanned image data has elapsed and the host I / F 127 of the control unit 120 completes the reception of the scanned image data, the processing from step S101 is executed again.

  As described above, according to the inkjet recording apparatus 1 according to the first embodiment, even when the reception of the scanned image data is delayed, the sheet 108 during the reversal of the carriage 100 and the recording head 118 is used. The transport distance is kept constant. Therefore, in the ink jet recording apparatus 1, a shift between the scanning of the recording head 118 and the conveyance of the paper 108 is prevented, and an image is accurately formed on the paper 108.

[Second Embodiment]
Next, a second embodiment will be described based on the drawings. Note that a description of the same components as those of the above-described embodiment will be omitted.

  In the ink jet recording apparatus 1 according to the second embodiment, the conveyance speed of the paper 108 while the carriage 100 and the recording head 118 are reversed is controlled according to the reception time of the scanned image data or the maintenance time of the recording head 118. .

  FIG. 13 is a diagram illustrating a flowchart of a printing process according to the second embodiment.

  As shown in FIG. 13, when printing is started in the inkjet recording apparatus 1, the paper 108 is started to be transported at the transport speed Vp1 in step S401. In step S <b> 402, the carriage 100 scans in the main scanning direction, and the recording head 118 forms an image on the paper 108.

  When the carriage 100 scans in one of the main scanning directions and stops at the position L or the position R shown in FIG. 3 (step S403: YES), and the printing is continued (step S404: YES), the step is performed. In S405, a reception time calculation process is executed.

  When the reception time Td of the scanned image data is obtained by the reception time calculation process, the control unit 120 executes a maintenance process in step S406.

(Maintenance processing)
FIG. 14 is a diagram illustrating a flowchart of maintenance processing in the second embodiment.

  In the maintenance process, first, in step S501, the control unit 120 confirms whether or not the recording head 118 is to be maintained. Maintenance such as idle ejection and wiping of the recording head 118 is performed, for example, at predetermined maintenance intervals.

  When performing maintenance (step S501: YES), the control unit 120 acquires the maintenance time Tm in step S502. The ROM 122, RAM 123, and NVRAM 124 of the control unit 120 are examples of storage means, and the type of maintenance of the recording head 118 and the maintenance time Tm for each type of maintenance are stored in any of them.

  Types of maintenance include, for example, idle ejection of the recording head 118, wiping of the nozzle surface of the recording head 118, and the like. When performing maintenance, the carriage 100 moves to the maintenance unit 91 and various types of maintenance are performed.

  When maintenance is not executed (step S501: NO), the control unit 120 sets the maintenance time Tm to zero in step S503. When maintenance is not executed, the carriage 100 stands by at the reverse position (position L or position R in FIG. 3) of the non-printing area.

  Returning to the flowchart of FIG. 13, when the control unit 120 acquires the maintenance time Tm, in step S <b> 407, the control unit 120 executes a conveyance control process.

(Transport control process)
FIG. 15 is a diagram illustrating a flowchart of the conveyance control process in the second embodiment.

  In the transport control process, as shown in FIG. 15, first, in step S601, the control unit 120 calculates the reception time Td of the scanned image data calculated by the reception time calculation process and the maintenance time Tm acquired by the maintenance process. Compare.

  If the reception time Td is greater than the maintenance time Tm (step S601: YES), in step S602, the processing time Tr required for processing in the non-printing area by the carriage 100 is set as the reception time Td. If the maintenance time Tm is greater than the reception time Td (step S601: NO), the processing time Tr is set as the maintenance time Tm in step S603.

  In step S <b> 604, the control unit 120 compares the processing time Tr with a preset waiting time Ts at the position L or R of the carriage 100.

  When the processing time Tr is shorter than the waiting time Ts (step S604: YES), in step S605, the control unit 120 sets the conveyance speed of the paper 108 while the carriage 100 is reversed at the time of printing (of the carriage 100). Set to the same speed Vp1 as during scanning.

  When the processing time Tr is equal to or longer than the waiting time Ts (step S604: NO), in step S606, the control unit 120 sets the conveyance speed of the paper 108 during the processing time Tr while the carriage 100 is reversed to the following formula. Set to Vp2 represented by (6).

Vp2 = Vp1 × Ts / Tr (6)
With the above-described conveyance control process, the conveyance speed of the paper 108 is controlled so that the conveyance distance of the paper 108 is kept constant while the carriage 100 and the recording head 118 are reversed, and the recording head 118 accurately images the paper 108. Can be formed.

  In the above-described conveyance control process, the conveyance speed of the paper 108 while the carriage 100 is reversed is changed. However, if the conveyance distance of the paper 108 while the carriage 100 is reversed can be kept constant, The conveyance time of the paper 108 may be changed. Further, it may be controlled to change both the conveyance speed and the conveyance time of the paper 108.

  Returning to the flowchart of FIG. 13, when the conveyance speed of the sheet 108 is set by the conveyance control process in step S <b> 407, the sheet 108 is set in a state where the carriage 100 is stopped at the reverse position or the maintenance unit 91 in step S <b> 408. It is transported at the transport speed.

  In step S408, when the reception of the scanned image data is completed or the maintenance of the recording head 118 is completed, the processing from step S401 is executed again.

  As described above, according to the inkjet recording apparatus 1 according to the second embodiment, the carriage 100 and the recording head 118 are reversed in the non-printing area even when the recording head 118 performs maintenance. The conveyance distance of the paper 108 is kept constant. Therefore, in the ink jet recording apparatus 1 according to the second embodiment, a shift between the scanning of the carriage 100 and the conveyance of the paper 108 is prevented, and an image is accurately formed on the paper 108.

[Third embodiment]
Next, a third embodiment will be described based on the drawings. Note that a description of the same components as those of the above-described embodiment will be omitted.

  In the inkjet recording apparatus 1 described above, if the carriage 100 waits in the non-printing area until the data reception is completed when reception of the scanned image data is delayed, the ink dryness of the printed portion at the start of scanning is changed due to a change in the standby time. Differences occur. When an image is formed by further overlaying ink on inks having different degrees of dryness as described above, color unevenness may occur in the image formed on the paper 108 as shown in FIG.

  FIG. 16 illustrates a state in which the carriage 100 that reciprocates in the main scanning direction forms an image with a constant density on the entire surface of the printing area 108a of the paper 108 that is conveyed in the sub-scanning direction. In the print area 108a of the paper 108, the carriage 100 reciprocates in the main scanning direction, and the recording head 118 discharges ink. Images are formed. Note that the recording head 118 mounted on the carriage 100 forms an image of each region while discharging ink over the region where the image has already been formed.

  Here, after the carriage 100 scans in the B direction to form an image in the area 119b12, reception of the next scanned image data is delayed, and the waiting time in the non-printing area of the carriage 100 scans another area. Suppose it is longer than In this case, an image is formed on the area 119b12 where the drying of the ink has progressed as the standby time is extended, so that the print density is increased between the area 119b12 and the other areas as shown in FIG. Differences occur and density unevenness is formed.

  Therefore, in the inkjet recording apparatus 1 according to the third embodiment, the control unit 120 waits in the non-printing area of the carriage 100 when reception of scanned image data for forming an image is not completed during the next and subsequent scans. Is extended as long as density unevenness does not occur.

  Thus, by appropriately extending the waiting time in the non-printing area of the carriage 100, it is possible to prevent the waiting time of the carriage 100 from being prolonged due to the reception delay of the scanned image data and to prevent the occurrence of density unevenness. Become.

  FIG. 17 is a diagram illustrating a flowchart of print processing according to the third embodiment.

  As shown in FIG. 17, when printing is started in the inkjet recording apparatus 1, the control unit 120 starts counting the number of scans N from [N = 1] in step S701. In step S <b> 702, the host I / F 127 of the control unit 120 receives scanned image data from a printer driver of a PC connected to the inkjet recording apparatus 1.

  In step S703, the carriage 100 starts scanning in one of the main scanning directions, and the recording head 118 discharges ink based on the scanned image data to form an image. When the carriage 100 completes scanning and stops in the non-printing area (step S704: YES), and continues printing (step S705: YES), in step S706, the control unit 120 scans N times. Is counted (N = N + 1).

  In step S707, the control unit 120 confirms whether or not reception of scanned image data used for the [N + α] -th scanning is completed. Here, α is a natural number of 1 or more.

  For example, in the case of α = 1, when the carriage 100 completes the first scanning (for example, scanning in the direction A in FIG. 16) and starts the second scanning, the control unit 120 sets 3 (= 2 + 1). ) It is confirmed whether or not reception of scanned image data used for the second scanning (for example, scanning in the direction B in FIG. 16) is completed. In this case, when the carriage 100 completes the fifth scan and starts the sixth scan, the control unit 120 completes reception of the scan image data used for the seventh (= 6 + 1) th scan. Check if it exists.

  For example, when α = 3, when the carriage 100 completes the first scan and starts the second scan, the control unit 120 receives the scan image data used for the fifth (= 2 + 3) scan. Check if it is complete. In this case, when the carriage 100 completes the fifth scan and starts the sixth scan, the control unit 120 completes reception of the scan image data used for the ninth (= 6 + 3) scan. Check if it exists.

  If the scanned image data used for the [N + α] -th scanning has been received (step S707: YES), the control unit 120 sets the waiting time in the non-printing area of the carriage 100 to Ts1 in step S708.

  If reception of the scanned image data used for the [N + α] -th scanning is not completed (step S707: NO), the control unit 120 sets the waiting time in the non-printing area of the carriage 100 to Ts2 in step S709. Set to. Here, the standby time Ts2 is longer than the standby time Ts1, and is a time set in advance within a range in which density unevenness does not occur due to drying of ink when a solid image is formed.

  As described above, when the reception of the scanned image data for the [N + α] th time is not completed, the control unit 120 extends the waiting time Ts in the non-printing area of the carriage 100. By extending the standby time and increasing the reception time of the scan image data, it becomes possible to receive more scan image data during the standby time, and the reception of the scan image data is delayed in the next and subsequent scans. Can be prevented. For this reason, in the next and subsequent scans, it is possible to prevent the waiting time in the non-printing area of the carriage 100 from being extended beyond the density unevenness generation level due to the reception delay of the scanned image data, thereby preventing the occurrence of density unevenness. It becomes possible.

  In step S710, the host I / F 127 of the control unit 120 receives the scanned image data until the set standby time Ts1 or standby time Ts2 elapses. When the set standby time Ts1 or standby time Ts2 has elapsed (step S711: YES), the processing after step S703 is executed, the carriage 100 starts scanning, the recording head 118 discharges ink, and the paper An image is formed at 108.

  FIG. 18 is a diagram illustrating print processing (α = 1) in the third embodiment.

  In the example shown in FIG. 18, first, reception of scanned image data used for image formation is completed during the first to third scans by time T31 when the first scan is started. In this case, when the first scan is completed, the number of scans is counted (N = 1 + 1 = 2), and since the third (= 2 + 1) th scan image data has been received, the waiting time Ts1 Set to

  The second scan is started at the time T33 when the standby time Ts1 has elapsed from the time T32 when the first scan is completed. Here, in the example shown in FIG. 18, the reception of the fourth scan image data is not completed during the waiting time Ts1 from the time T32 to the time T33.

  When the second scan is completed at time T34, the number of scans is counted (N = 2 + 1 = 3), and reception of the fourth (= 3 + 1) th scan image data is not completed, so the standby time is Ts2. Is set. Here, in the example shown in FIG. 18, the reception of the fourth and fifth scan image data is completed during the waiting time Ts2 from time T34 to time T35.

  Next, the third scan is started at the time T35 when the standby time Ts2 has elapsed from the time T34 when the second scan is completed. When the third scan is completed at time T36, the number of scans is counted (N = 3 + 1 = 4), and the fifth (= 4 + 1) th scan image data has been received, so the standby time is set to Ts1. The In the example shown in FIG. 18, the reception of the sixth and seventh scan image data is completed during the waiting time Ts1 from time T36 to time T37.

  The same processing is repeated after the fourth scan, and the number of scans N is counted when the scan is completed. When α = 1, the waiting time is determined based on whether or not the [N + 1] th scan image data has been received. Is set to Ts1 or Ts2.

  FIG. 19 is a diagram illustrating print processing (α = 3) in the third embodiment.

  In the example shown in FIG. 19, first, reception of the first to fifth scan image data is completed by time T41 when the first scan is started. In this case, when the first scan is completed, the number of scans is counted (N = 1 + 1 = 2), and the fifth (= 2 + 3) th scan image data has been received. Set to

  The second scan is started at time T43 when the standby time Ts1 has elapsed from the time T42 at which the first scan is completed. Here, in the example shown in FIG. 19, the reception of the sixth scan image data is not completed during the waiting time Ts1 from time T42 to time T43.

  When the second scan is completed at time T44, the number of scans is counted (N = 2 + 1 = 3), and the reception of the sixth (= 3 + 3) th scan image data is not completed, so the standby time is Ts2. Is set. In the example shown in FIG. 19, the reception of the sixth scan image data is completed during the waiting time Ts2 from time T44 to time T45.

  Next, the third scan is started at the time T45 when the standby time Ts2 has elapsed from the time T44 at which the second scan is completed. When the third scan is completed at time T46, the number of scans is counted (N = 3 + 1 = 4), and since the reception of the seventh (= 4 + 3) th scan image data is not completed, the standby time is Ts2. Is set. In the example shown in FIG. 19, the reception of the seventh and eighth scan image data is completed during the waiting time Ts2 from time T46 to time T47.

  Next, the fourth scan is started at the time T47 when the standby time Ts2 has elapsed from the time T46 when the third scan is completed. When the fourth scan is completed at time T48, the number of scans is counted (N = 4 + 1 = 5), and since the 8th (= 5 + 3) th scan image data has been received, the standby time is set to Ts1. The In the example shown in FIG. 19, the reception of the ninth and tenth scan image data is completed during the waiting time Ts1 from time T48 to time T49.

  The same processing is repeated after the fifth scan, and the number of scans N is counted when the scan is completed. When α = 3, the waiting time is determined based on whether or not the [N + 3] th scan image data has been received. Is set to Ts1 or Ts2.

  As described above, in the ink jet recording apparatus 1 according to the third embodiment, when reception of scanned image data used for image formation is not completed at the next and subsequent scans, in the non-printing area of the carriage 100. The waiting time Ts is extended. By securing the time for receiving the scanned image data before the start of scanning, it is possible to prevent the waiting time Ts of the carriage 100 from being extended due to the reception delay of the scanned image data during the next and subsequent scans, and suppress the occurrence of density unevenness. It becomes possible to do.

  Although the image forming apparatus and the image forming method according to the embodiments have been described above, the present invention is not limited to the above embodiments, and various modifications and improvements can be made within the scope of the present invention. The present invention is not limited to an inkjet image forming apparatus, and an image forming apparatus including a recording head that reciprocates in the main scanning direction to form an image on the recording medium with respect to the recording medium conveyed in the sub-scanning direction. Any device can be applied.

1 Inkjet recording device (image forming device)
101 Conveying belt (conveying means)
108 paper (recording medium)
111 Sub-scanning motor (conveying means)
118 Recording Head 120 Control Unit (Control Unit)
127 Host I / F (Receiving means)

JP 2004-338215 A

Claims (6)

Conveying means for conveying the recording medium;
A recording head that reciprocally scans in a direction perpendicular to the conveyance direction of the recording medium while the recording medium is conveyed by the conveyance unit, and forms an image on the recording medium;
Receiving means for receiving scanned image data while the recording head is waiting in a non-printing area;
Control means for controlling the transport distance of the recording medium by the transport means while the recording head waits in the non-printing area based on the reception time of the scanned image data obtained from the communication speed of the receiving means; An image forming apparatus comprising: The receiving means receives the communication speed measurement data having a predetermined data size and the size of the scanned image data while the recording head is reversed in the non-printing area,
The said control means calculates | requires the communication speed of the said receiving means from the reception time of the data for said communication speed measurement, and calculates | requires the said reception time from the size and the said communication speed of the said scanning image data. Image forming apparatus. The control means compares the reception time with a standby time in which the recording head waits in the non-printing area, and when the reception time is less than the standby time, the transport speed of the transport means is set to a first transport speed. The transport speed of the transport means is set to a second transport speed that is lower than the first transport speed when the reception time is equal to or longer than the standby time. Image forming apparatus. The control means compares the reception time with a standby time for which the recording head waits in the non-printing area. When the reception time is equal to or longer than the standby time, the recording head waits in the non-printing area. 3. The image forming apparatus according to claim 1, wherein after the recording medium is conveyed for the predetermined distance, the conveying unit stops conveying the recording medium. Storage means for storing the type of maintenance of the recording head and the maintenance time for each maintenance;
The control means includes the maintenance time, the reception time, and the waiting time for the recording head to wait in the non-printing area when the recording head performs maintenance in the non-printing area during printing on the recording medium. If the maintenance time is less than the reception time and the reception time is less than the standby time, the conveyance speed of the conveyance means is set to the first conveyance speed, and the maintenance time or the reception time 3. The image forming apparatus according to claim 1, wherein when the time is equal to or longer than the waiting time, the transport speed of the transport unit is set to a second transport speed lower than the first transport speed. Conveying means for conveying the recording medium;
An image forming method in an image forming apparatus, comprising: a recording head that reciprocally scans in a direction orthogonal to a conveyance direction of the recording medium while the recording medium is conveyed by the conveying unit, and forms an image on the recording medium. Because
A receiving step of receiving scanned image data while the recording head is waiting in a non-printing area;
And a control step of controlling a transport distance of the recording medium by the transport unit while the recording head is waiting in the non-printing area based on a reception time of the scanned image data. Method.

Images