JP2011143556A - Image forming apparatus and method for controlling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To more smoothly start formation of an image by reducing loss of movement of a delivering head when the formation of the image is started. <P>SOLUTION: Positions of both ends of dots (right end position Rp and left end position Lp) formed at a first path is determined from printing data of the first path (S100 and 110), and the moving direction of the first path is set and a waiting position Tp is set so that between the determined right end position Rp and left end position Lp, such a position that is nearer to the current location Gp of a carriage carrying the delivering head becomes to a printing starting position (S120-S190). The carriage is moved to the set waiting position Tp (S200), and a paper feeding processing is performed and a print processing is executed (S210 and 220). By this arrangement, the waiting position Tp of the carriage is made to be a position near the printing starting position, and when the print processing is started, the delivering head can be rapidly moved to the printing starting position. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image forming apparatus and a control method therefor. More specifically, the image forming apparatus includes a carriage equipped with a discharge head that discharges liquid, conveys a predetermined amount of paper for each pass, and in a direction orthogonal to the conveyance direction. The present invention relates to an image forming apparatus that forms a plurality of dots as an image by discharging liquid from the discharge head onto the paper while reciprocating a carriage, and a control method thereof.

  Conventionally, as this type of image forming apparatus, there has been proposed an apparatus that performs printing by scanning a discharge head in a direction perpendicular to the conveyance direction while conveying a plurality of types of recording papers having different sizes with reference to the center position. (For example, refer to Patent Document 1). In this apparatus, the ejection head is made to wait at a standby position corresponding to the position of the end of the recording paper to be used, and the ejection head that has been waiting at the standby position is moved when feeding of the recording paper is completed. Start printing. As a result, the printing head can be started smoothly by shortening the distance that the ejection head moves without ejecting ink at the start of printing and moving the ejection head without loss.

JP 2009-241261 A

  In the above-described image forming apparatus, an effect can be obtained when the printing start position is in the vicinity of the end of the recording paper, but depending on the printing start position, the movement loss of the ejection head at the start of printing can be reduced. In some cases, it cannot be made smaller and the desired effect cannot be obtained.

  The main object of the image forming apparatus and the control method thereof according to the present invention is to start the image formation more smoothly by reducing the movement loss of the ejection head when starting the image formation.

  The image forming apparatus and the control method thereof according to the present invention employ the following means in order to achieve the main object described above.

The image forming apparatus of the present invention includes:
A carriage equipped with a discharge head for discharging liquid is provided, and a predetermined amount of paper is transported for each pass, and liquid is discharged from the discharge head onto the paper while reciprocating the carriage in a direction perpendicular to the transport direction. An image forming apparatus that forms a plurality of dots as an image by
Moving means for moving the carriage;
When image data is received and image formation is instructed, a dot formation start position that is the position of the first dot formed in the first pass is determined based on the image data, and the movement direction of the carriage in the first pass Standby position setting means for setting the carriage standby position closer to the rear side as the dot formation start position is closer to the rear side than the determined dot formation start position with reference to
When the standby position is set, the moving means is controlled so that the carriage moves to the set standby position, and when the paper feeding is completed, the carriage starts reciprocating from the standby position. And a control means for controlling the ejection head so as to eject the liquid onto the fed paper based on the image data.

  In the image forming apparatus of the present invention, when image data is received and an image formation is instructed, a dot formation start position that is a position of a dot to be formed first in the first pass is determined based on the image data, and the carriage When the stand-by position of the carriage is set, the carriage stand-by position is set on the back side as the dot-formation start position is located on the back side with respect to the moving direction of the first pass. The moving means is controlled so that the carriage moves to the set standby position, and when the paper feeding is completed, the moving means is controlled so that the carriage starts reciprocation from the standby position, and the paper is fed based on the image data. The ejection head is controlled to eject the liquid onto the printed paper. Thus, the carriage can be quickly moved to the dot formation start position when starting the image formation. As a result, it is possible to start the image formation more smoothly by reducing the movement loss of the ejection head when starting the image formation.

  In such an image forming apparatus of the present invention, the standby position setting means is a means for setting, as the standby position, a position that is a predetermined distance away from the dot formation start position with respect to the moving direction. You can also. In this way, the standby position can be set with a simple process. In this aspect of the image forming apparatus of the present invention, the control means is a means for controlling the moving means so that the carriage reciprocates with a constant speed movement, and the standby position setting means is configured to set the predetermined distance as the predetermined distance. Further, it may be a means that uses a distance necessary for acceleration until the carriage moves at a constant speed.

  Further, in the image forming apparatus of the present invention capable of ejecting liquid from the ejection head in both the forward path and the backward path, the standby position setting unit includes two end portions of dots formed in the first pass. The dot forming end may be a means for setting the moving direction of the first pass of the carriage and the standby position so that the dot forming end close to the current position of the carriage becomes the dot forming start position. it can. In this way, the carriage can be quickly moved to the standby position.

The control method of the image forming apparatus of the present invention includes:
A carriage on which a discharge head for discharging liquid is mounted; and a moving means for moving the carriage. The sheet is conveyed by a predetermined amount for each pass, and the carriage is reciprocated in a direction orthogonal to the conveyance direction. A control method of an image forming apparatus that forms a plurality of dots as an image by discharging liquid from a discharge head onto the paper,
(A) When image data is received and image formation is instructed, a dot formation start position that is a position of a dot formed first in the first pass is determined based on the image data, and the first pass of the carriage The carriage standby position is set closer to the front side than the determined dot formation start position with respect to the moving direction of
(B) The moving means is controlled so that the carriage moves to the set standby position when the standby position is set, and the carriage is reciprocated from the standby position when the paper feeding is completed. The moving unit is controlled to start moving, and the discharge head is controlled to discharge liquid onto the fed paper based on the image data.

  In the control method of the image forming apparatus according to the present invention, when image data is received and an image formation is instructed, a dot formation start position that is the position of the first dot formed in the first pass is determined based on the image data. Then, the carriage standby position is set to the back side as the dot formation start position is closer to the rear side than the dot formation start position with respect to the moving direction of the first pass of the carriage, and the standby position is set. The moving means is controlled so that the carriage moves to the set standby position in the case of the paper, and when the paper feeding is completed, the moving means is controlled so that the carriage starts to reciprocate from the standby position and based on the image data. The ejection head is controlled to eject the liquid onto the fed paper. Thus, the carriage can be quickly moved to the dot formation start position when starting the image formation. As a result, it is possible to start the image formation more smoothly by reducing the movement loss of the ejection head when starting the image formation.

1 is a configuration diagram showing an outline of the configuration of an inkjet printer 20. 6 is a flowchart illustrating an example of a print processing routine. Explanatory drawing which shows an example of the right end position Rp and the left end position Lp. Explanatory drawing which shows an example of waiting position Tp. It is explanatory drawing which shows the relationship between the change of the right end position Rp, and the standby position Tp. 9 is a flowchart illustrating an example of a printing process routine according to a modification.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing an outline of a configuration of an inkjet printer 20 which is an embodiment of an image forming apparatus of the present invention.

  As shown in FIG. 1, the inkjet printer 20 of the present embodiment includes a paper feed mechanism 31 that feeds the paper S from the back to the front (transport direction) in the figure by driving the paper feed roller 35 by the drive motor 33, A printer mechanism 21 that performs printing by ejecting ink droplets from the print head 24 onto the sheet S fed onto the platen 38 by the mechanism 31, and a print head 24 that is formed at the right end of the platen 38 in the drawing and that is necessary. Accordingly, a capping device 40 that performs cleaning by suctioning ink in the print head 24 and a controller 70 that controls the entire inkjet printer 20 are provided. The position on the capping device 40 is called a home position.

  The printer mechanism 21 includes a carriage motor 34a disposed on the right side of the mechanical frame 80 in the drawing, a driven roller 34b disposed on the left side of the mechanical frame 80 in the drawing, and a carriage installed on the carriage motor 34a and the driven roller 34b. The carriage 22 reciprocates in the left-right direction (main scanning direction) in the figure perpendicular to the transport direction of the paper S along the guide 28 by the carriage belt 32 as the carriage motor 34a is driven. An ink cartridge 26 that individually contains ink of each color of yellow (Y), magenta (M), cyan (C), and black (K), which is mounted and contains a dye or pigment as a colorant in water as a solvent; The ink supplied from the ink cartridge 26 is pressurized from a nozzle (not shown). And a print head 24 for ejecting ink droplets. Further, a linear encoder 36 for detecting the position of the carriage 22 is disposed on the rear surface of the carriage 22, and the position of the carriage 22 is managed by the linear encoder 36. Here, a plurality of nozzle rows each including nozzles (not shown) are formed in parallel in the main scanning direction in the print head 24. In this embodiment, the central position in the main scanning direction of the region in which these nozzle rows are formed. Is managed as the position of the carriage 22. Further, the position of the carriage 22 is represented by the value of the left-right coordinate with the home position described above as the origin. The print head 24 employs a system in which a voltage is applied to the piezoelectric element to deform the piezoelectric element and pressurize the ink. Further, although an on-carriage type in which the ink cartridge 26 is mounted on the carriage 22 is illustrated, an off-carriage type in which the ink cartridge 26 is disposed at a place other than the carriage 22 may be used.

  The controller 70 is configured as a microprocessor centered on the CPU 72, and includes a ROM 73 that stores various processing programs and various data, a RAM 74 that temporarily stores data, and a flash memory 75 that can write and delete data. And an interface (I / F) 76 for exchanging information with an external device, and an input / output port (not shown). The RAM 74 is provided with a print buffer area, and print data sent from the user PC 10 which is a general-purpose personal computer via the I / F 76 is stored in the print buffer area. A position signal from the linear encoder 36 is input to the controller 70 via an input port. The controller 70 outputs a drive signal to the print head 24, a drive signal to the drive motor 33, a drive signal to the carriage motor 34a, and the like via an output port. A drive signal is output to the carriage motor 34a so that the carriage 22 accelerates from the stopped state and moves at a constant speed, and then decelerates and stops.

  In the inkjet printer 20 of the present embodiment configured as described above, when dot data developed on the user PC 10 side is received as print data together with a print execution instruction, it is output to a print buffer area provided in the RAM 74. Then, the paper feed roller 35 is rotated by the drive motor 33 to convey the paper S onto the platen 38, and the carriage 22 is reciprocated by the carriage motor 34a, and at the same time, the respective piezoelectric elements (not shown) of the print head 24 are driven. An image is formed on the paper S by ejecting each color ink to form dots. The inkjet printer 20 has a bidirectional printing mode as a printing mode. In the bidirectional printing mode, both the forward path in the main scanning direction (left direction in FIG. 1) and the backward path (right direction in FIG. 1). Thus, printing is performed by ejecting ink droplets from the print head 24. Further, the inkjet printer 20 controls the carriage 22 by changing the stop position of the carriage 22 for each pass according to the print start position of the next pass so that the movement amount of the carriage 22 for each pass is minimized. So-called logical seek is possible. The dot data is transferred to the print head 24 as image data arranged in the order corresponding to the moving direction of the carriage 22 for each data for one pass, and the piezoelectric elements of the print head 24 are based on the transferred image data. Driving is performed.

  Next, the operation of the ink jet printer 20 of the present embodiment configured as described above, in particular, the operation during the printing process will be described. FIG. 2 is a flowchart illustrating an example of a print processing routine executed by the controller 70. This routine is executed when print data is input from the user PC 10 in the bidirectional print mode.

  When this routine is executed, the CPU 72 of the controller 70 first obtains the first pass print data from the buffer area of the RAM 74 (step S100), and both ends of the dots formed in the first pass from the obtained print data. Are determined (right end position Rp, left end position Lp) (step S110). FIG. 3 is an explanatory diagram illustrating an example of the right end position Rp and the left end position Lp. As shown in the figure, a dot formation area (print area) where dots are formed on the paper S can be recognized from the print data of the first pass, and the positions of both ends of this area are the right end positions Rp (right side in the figure). , Left end position Lp (left side in the figure). In the print data, positions where dots are formed are defined, and the smallest value among the horizontal coordinate values of the linear encoder 36 corresponding to these positions is set as the right end position Rp and the largest value is set. It can be determined as the left end position Lp.

  Next, the current position Gp of the carriage 22 is acquired from the linear encoder 36 (step S120), and the absolute value of the value obtained by subtracting the right end position Rp from the acquired current position Gp is calculated as the distance Rk (step S130). The absolute value of the value obtained by subtracting the left end position Lp from the position Gp is calculated as the distance Lk (step S140). Next, the calculated distance Rk is compared with the distance Lk (step S150). By comparing this size, it is possible to determine which of the right end position Rp and the left end position Lp is closer to the current position Gp of the carriage 22. Note that, at the beginning of printing, since the normal carriage 22 is at a position on the home position, it is determined that the distance Rk is equal to or less than the distance Lk. On the other hand, after the start of printing, the end position of the final pass in the printing of the previous page may be the current position Gp due to the above-described logical seek, and the distance Lk is smaller than the distance Rk depending on the position. It is determined that the distance Rk is not less than the distance Lk.

  When it is determined in step S150 that the distance Rk is equal to or less than the distance Lk, the moving direction of the carriage 22 in the first pass is set to the forward direction (step S160), and the predetermined distance α necessary for acceleration of the carriage 22 is subtracted from the right end position Rp. The position (Rp−α) is set to the standby position Tp of the carriage 22 (step S170). That is, in this case, the right end position Rp is set as the printing start position, and a position that is separated from the printing start position by a predetermined distance α to the front side in the moving direction of the carriage 22 is set as the standby position Tp. The predetermined distance α is stored in advance in the ROM 73 as a value obtained by converting the distance required for acceleration from the stop state to the constant speed by accelerating the carriage 22 from the stopped state to the coordinate value of the linear encoder 36. On the other hand, when it is determined in step S150 that the distance Rk is not less than or equal to the distance Lk, that is, when the distance Rk is greater than the distance Lk, the movement direction of the carriage 22 in the first pass is set to the return path direction (step S180). A position (Lp + α) obtained by adding a predetermined distance α to the standby position Tp of the carriage 22 is set (step S190). In other words, in this case, the left end position Lp is set as the print start position, and a position separated by a predetermined distance α from the print start position to the front side in the movement direction of the carriage 22 is set as the standby position Tp.

  When the standby position Tp is set in this way, the carriage motor 34a is controlled to move the carriage 22 to the standby position Tp (step S200). Here, FIG. 4 is an explanatory diagram showing an example of the standby position Tp, FIG. 4A shows the standby position Tp when the distance Rk is determined to be equal to or less than the distance Lk, and FIG. The standby position Tp when it is determined that the distance Rk is not less than the distance Lk is shown. In this way, the distance Rk and the distance Lk are compared, and the carriage 22 is moved by setting the position closer to the current position Gp as the standby position Tp. Therefore, the carriage 22 is moved more smoothly to the standby position Tp. be able to. FIG. 5 is an explanatory diagram showing the relationship between the change in the right end position Rp and the standby position Tp. FIG. 5 shows the relationship when the distance Rk is determined to be equal to or less than the distance Lk and the movement direction of the carriage 22 in the first pass is set to the forward direction (left direction in FIG. 5). Considering the case where the area (printing area) in which dots are formed from the print data of the first pass changes to areas (1), (2), and (3) as shown in the figure, the right end position Rp is also the right end position Rp. It changes as (1), (2), (3). At this time, the standby position Tp is the standby positions Tp (1), (2), and (3) that are separated from the right end positions Rp (1), (2), and (3) by a predetermined distance α, respectively. That is, with reference to the movement direction of the carriage 22 in the first pass, the standby position Tp of the carriage 22 is set so that it is closer to the front side of the right end position Rp and closer to the back side in the movement direction. Will be. Thereby, the carriage 22 can be kept waiting at a more appropriate position near the print start position.

  When the carriage 22 is moved to the standby position Tp in this way, the drive motor 33 is controlled to perform the paper feeding process for the paper S (step S210). The paper feeding process may be performed after the carriage 22 has moved to the standby position Tp, or may be performed while the carriage 22 is moving. When the paper feeding process is performed, a printing process for one page is executed (step S220). In the printing process, the carriage motor 34a is controlled so that the carriage 22 reciprocates in the main scanning direction, and the piezoelectric element of the print head 24 is driven so that ink is ejected onto the paper S based on the print data. This is done by repeating the process of controlling the drive motor 33 so that the paper S is transported by a predetermined amount in the transport direction. Here, since the carriage 22 is waiting at a standby position Tp that is a predetermined distance α away from the print start position when printing is started, the carriage 22 can be quickly moved to the print start position. For this reason, since the distance to which the carriage 22 is moved can be shortened without ejecting ink from the print head 24, the printing process can be started more smoothly with less movement loss of the print head 24. When the printing process is executed in this manner, the printed sheet S is discharged (step S230), and it is determined whether or not the next page (next sheet S) is printed (step S240). When it is determined that there is a next page, the process returns to step S100 to repeat the process. When it is determined that there is no next page, the carriage 22 is moved to the home position (step S250), and this routine is terminated. Since the standby position Tp of the carriage 22 is set for each page (each sheet S to be fed), the movement loss of the print head 24 should be reduced each time the printing process for each page is started. As a result, the throughput of the printing process can be improved.

  Here, the correspondence between the components of the present embodiment and the components of the present invention will be clarified. The carriage belt 32, the carriage motor 34a, and the driven roller 34b that move the carriage 22 according to the present embodiment correspond to the “moving unit” of the present invention, and the controller 70 that executes the processes of steps S100 to S190 of the print processing routine of FIG. Corresponds to “standby position setting means”, and the controller 70 that executes the processes of steps S200 and S220 of the print processing routine of FIG. 2 corresponds to “control means”.

  According to the ink jet printer 20 of the present embodiment described in detail above, the right end position Rp and the left end position Lp, which are the positions of both ends of the dot formed in the first pass, are determined from the first pass print data, and determined. A position close to the current position Gp of the carriage 22 on which the print head 24 is mounted is determined from the right end position Rp and the left end position Lp, and the moving direction of the first pass is set so that the position determined to be close becomes the print start position. At the same time, a position a predetermined distance α required for acceleration from the printing start position is set as the standby position Tp, and the carriage 22 is moved to the set standby position Tp, and then the printing process is performed on the fed paper S. Therefore, when starting the printing process, the carriage 22 can be quickly moved to the printing start position. As a result, the movement loss of the print head 24 can be reduced and the printing process can be started more smoothly. Further, since the standby position Tp is set at a position a predetermined distance α from the print start position, the standby position Tp can be set by a simple process.

  In addition, this invention is not limited to the embodiment mentioned above at all, and it cannot be overemphasized that it can implement with a various aspect, as long as it belongs to the technical scope of this invention.

  In the above-described embodiment, the description is applied to the case where printing is performed using the bidirectional printing mode as the printing mode. However, the printing may be performed in one direction (for example, the forward direction) without using the bidirectional printing mode. Good. In addition, although the moving direction of the carriage 22 in the first pass in the bidirectional printing mode is set, printing may be performed in a predetermined direction (for example, the forward direction) without setting the moving direction. Good. In this case, instead of the print processing routine of FIG. 2, the print processing routine of the modification shown in FIG. 6 may be executed. Hereinafter, this processing routine will be described. In FIG. 6, the same processes as those in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted. When print data for the first pass is acquired in step S100, the right end position Rp of the dot formed in the first pass is determined from the acquired print data (step S110a). Next, the standby position Tp is set by subtracting the predetermined distance α from the right end position Rp (step S160a), the carriage 22 is moved to the standby position Tp in step S200, and the processing from step S210 onward is executed. Thereby, the standby position Tp can be set by simpler processing, and the printing process can be started smoothly.

  In the above-described embodiment, the standby position Tp is set to a position separated from the print start position (right end position Rp or left end position Lp) by a predetermined distance α necessary for acceleration. However, the present invention is not limited to this, and the right end position Rp. Alternatively, it may be set at a position separated from the left end position Lp by an arbitrary predetermined distance. Alternatively, the distance is not limited to a predetermined distance, and may be set to a position separated by a distance that varies according to the position of the right end position Rp or the left end position Lp.

  In the above-described embodiment, the current position Gp is acquired with the center position in the main scanning direction of the region where the nozzle row is formed as the position of the carriage 22. However, the present invention is not limited to this, and the position where the position of the carriage 22 can be managed. Any position may be used. In this case, the distance between the current position to be acquired and the leftmost nozzle row in the main scanning direction and the distance between the current position to be acquired and the rightmost nozzle row in the main scanning direction are grasped in advance. When calculating Rk, the distance to the leftmost nozzle row is taken into account, and when calculating the distance Lk, the distance to the rightmost nozzle row is taken into account.

  In the above-described embodiment, the inkjet printer 20 is shown as an example of the image forming apparatus of the present invention. However, the present invention is not limited to this as long as it forms a dot on a sheet by discharging a liquid. For example, the present invention may be applied to office automation equipment such as a facsimile machine and a multifunction machine.

  10 user PC, 20 inkjet printer, 21 printer mechanism, 22 carriage, 24 print head, 26 ink cartridge, 28 guide, 31 paper feed mechanism, 32 carriage belt, 33 drive motor, 34a carriage motor, 34b driven roller, 35 paper feed Roller, 36 linear encoder, 38 platen, 40 capping device, 70 controller, 72 CPU, 73 ROM, 74 RAM, 75 flash memory, 76 interface (I / F), 80 mechanical frame, S paper.

Claims (5)

A carriage equipped with a discharge head for discharging liquid is provided, and a predetermined amount of paper is transported for each pass, and liquid is discharged from the discharge head onto the paper while reciprocating the carriage in a direction perpendicular to the transport direction. An image forming apparatus that forms a plurality of dots as an image by
Moving means for moving the carriage;
When image data is received and image formation is instructed, a dot formation start position that is the position of the first dot formed in the first pass is determined based on the image data, and the movement direction of the carriage in the first pass Standby position setting means for setting the carriage standby position closer to the rear side as the dot formation start position is closer to the rear side than the determined dot formation start position with reference to
When the standby position is set, the moving means is controlled so that the carriage moves to the set standby position, and when the paper feeding is completed, the carriage starts reciprocating from the standby position. An image forming apparatus comprising: a control unit that controls the moving unit to control the discharge head to discharge liquid onto the fed paper based on the image data.   The image forming apparatus according to claim 1, wherein the standby position setting unit is a unit that sets, as the standby position, a position that is a predetermined distance away from the dot formation start position with respect to the moving direction. The image forming apparatus according to claim 2,
The control means is means for controlling the moving means so that the carriage reciprocates with constant speed movement,
The image forming apparatus, wherein the standby position setting unit uses a distance necessary for acceleration until the carriage moves at a constant speed as the predetermined distance. The image forming apparatus according to any one of claims 1 to 3, wherein the liquid can be discharged from the discharge head in both an outward path and a return path.
The standby position setting means is configured so that the dot formation end close to the current position of the carriage among the two dot formation ends that are both ends of the dots formed in the first pass becomes the dot formation start position. An image forming apparatus as means for setting a moving direction of the first pass and the standby position. A carriage on which a discharge head for discharging liquid is mounted; and a moving means for moving the carriage. The sheet is conveyed by a predetermined amount for each pass, and the carriage is reciprocated in a direction orthogonal to the conveyance direction. A control method of an image forming apparatus that forms a plurality of dots as an image by discharging liquid from a discharge head onto the paper,
(A) When image data is received and image formation is instructed, a dot formation start position that is a position of a dot formed first in the first pass is determined based on the image data, and the first pass of the carriage The carriage standby position is set closer to the front side than the determined dot formation start position with respect to the moving direction of
(B) The moving means is controlled so that the carriage moves to the set standby position when the standby position is set, and the carriage is reciprocated from the standby position when the paper feeding is completed. A control method for an image forming apparatus, wherein the moving unit is controlled to start moving, and the discharge head is controlled to discharge liquid onto the fed paper based on the image data.

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