JP5494463B2 - Inkjet recording device - Google Patents

Description

  The present invention relates to an ink jet recording apparatus that records an image on a recording medium.

  2. Description of the Related Art Conventionally, a carriage that reciprocates in a predetermined scanning direction with respect to a recording medium and an ink-jet head mounted on the carriage have been scanned once (forward or backward movement: hereinafter also referred to as a pass). In other words, a so-called serial type ink jet recording apparatus is known in which ink is ejected from an ink jet head toward a recording medium during the recording of an image on the recording medium.

  In the above-described ink jet recording apparatus, the carriage is temporarily stopped at the time of reciprocating reversal, that is, before finishing the path in one direction and starting the path in the reverse direction. It is controlled to stop at the set target stop position.

  Here, it is difficult to make the carriage stop position coincide with the target stop position due to errors in the carriage position control, etc., but if the actual stop position deviates greatly from the target stop position, the following problems will occur. May occur. When the actual stop position is shifted to the outside (downstream of the carriage movement direction) with respect to the target stop position, it interferes with other members and mechanisms of the printing apparatus that are located outside the carriage movement range during printing. There is a risk of damage or hindering the operation of these other members and mechanisms. In addition, when the stop position is shifted inward (upstream in the carriage movement direction), it is not possible to secure a sufficient acceleration distance (running distance) in the next pass from the stop position. In particular, when performing so-called bi-directional printing in which ink is ejected in each of two forward and backward passes, so-called bi-directional printing is performed, it is accelerated to a predetermined speed before reaching the ejection start position in the next pass. Otherwise, ink ejection is started with insufficient acceleration, and there is a risk that the print quality will be deteriorated, for example, a landing position shift will occur. Thus, normally, the stop allowable range of a predetermined width including the target stop position is set in a range in which the above-described problems do not occur, and is controlled to stop at the target stop position. If it does not fall within the stop allowable range, the stop operation is retried (retry). That is, after the stopped carriage is moved slightly, it is again stopped within the stop allowable range.

  In relation to this, in Patent Document 1, in an inkjet recording apparatus capable of bidirectional printing, the target stop position of each pass is changed from the first dot formation position (ejection start position) of the next pass to the next pass. Is set to a position shifted by a distance obtained by adding the necessary acceleration distance and an offset value corresponding to an error in stop position control. That is, theoretically, the target stop position is further shifted by the error of the carriage stop position control where a position shifted by the necessary acceleration distance in the next pass may be set as the target stop position. In other words, a stop allowable range corresponding to an error in stop position control is set for the target stop position of the carriage.

Japanese Patent Laid-Open No. 2005-169973

  Incidentally, the ink ejection range (image recording area) in the carriage movement direction of the inkjet head in each pass is determined by the size (width) of the recording medium and the size and position of the image to be recorded on the recording medium. For example, when an image or the like is formed only in the center of the recording medium (that is, when there are many margins) or when recording is performed on a recording medium with a small size (width), the ejection of ink in each pass is The process ends considerably inside (upstream side in the carriage movement direction) with respect to the maximum image recording range in the scanning direction of the inkjet head. In this case, by decelerating the carriage promptly after the end of injection in each pass, the carriage can be stopped on the considerably front side, so that it interferes with other members and the like located outside the carriage movement range as described above. The problem does not occur at first.

  However, in the conventional carriage stop position control described in Patent Document 1, the above-described stop allowable range including the target stop position is fixed to a predetermined width (a width corresponding to a control error). When stopping beyond the stop allowable range of the predetermined width for some reason, the stop operation is always retried regardless of whether or not the above-described failure such as interference with other members occurs. It was broken. In other words, the start of the next pass is delayed due to unnecessary retries, resulting in a problem that the recording speed is lowered.

  An object of the present invention is to improve the recording speed by reducing unnecessary retries of the carriage stop operation as much as possible.

An ink jet recording apparatus according to a first aspect of the invention is mounted on a carriage that reciprocates in a predetermined scanning direction, a transport unit that transports a recording medium in a transport direction that intersects the scanning direction, and the carriage together with the carriage. An ink jet head that ejects ink onto the recording medium while reciprocating in the scanning direction; position detecting means for detecting a position of the carriage in the scanning direction; and based on position information detected by the position detecting means. Recording control means for controlling the reciprocation of the carriage, and for recording an image on the recording medium by ejecting ink from the inkjet head at least one of the forward movement and the backward movement of the carriage;
The recording control means sets an ejection end position of the inkjet head corresponding to an image recording area of the recording medium for each pass of forward or backward movement of the carriage that ejects ink from the inkjet head. Injection end position determining means to be set; target stop position setting means for setting a target stop position of the carriage after reaching the injection end position for each pass, according to the injection end position; Similarly, it comprises a stop allowable range setting means for setting a stop allowable range of the carriage including the target stop position for each pass.
Further, the stop allowable range setting means expands the stop allowable range to the downstream side in the carriage movement direction as the target stop position corresponding to the injection end position is on the upstream side in the carriage movement direction .
In response to the stop allowable range setting means expanding the stop allowable range to the downstream side in the carriage movement direction, the target stop position setting means sets the previously set target stop position of the carriage to the carriage. It is characterized by changing to the downstream side in the moving direction .

The more the target stop position of the carriage set according to the ejection end position of each pass is on the upstream side in the carriage movement direction, the distance from this target stop position to other members and the like located on the downstream side in the carriage movement direction ( Therefore, the stop allowable range set for the target stop position is widened to the downstream side in the carriage movement direction. As a result, the frequency at which the carriage stops beyond the stop allowable range is reduced, and unnecessary stop operation retries are reduced.
In addition, when the carriage stop position deviates from the target stop position, it is considered that the frequency (probability) of deviation does not change between the upstream side and the downstream side in the movement direction. Therefore, when the allowable stop range is expanded to the downstream side, the actual stop position is changed by changing the target stop position to the downstream side and increasing the allowable range upstream of the target stop position accordingly. Retry can be reduced when the position deviates inward from the target stop position.

In the ink jet recording apparatus according to a second aspect, in the first aspect, the target stop position setting means corresponds to the maximum image recording range in the scanning direction, and the target stop farthest downstream in the moving direction of the carriage. The limit stop position that is the position is memorized,
The allowable stop range setting means calculates a margin length, which is a distance between the target stop position determined by the target stop position setting means and the limit stop position, for each pass. The stop allowable range is widened to the downstream side in the movement direction of the carriage by the length.

  The limit stop position of the carriage in the present invention is the farthest target stop position corresponding to the case where the ejection end position is the most downstream position in the carriage movement direction when the inkjet head records in the maximum image recording range. It is. In the present invention, how far the target stop position of the carriage in each pass is from the limit stop position (margin length) is calculated, and the allowable stop range is expanded to the downstream side as much as this margin length. That is, the allowable stop range is maximized within a range that does not cause interference with other members, and unnecessary retries can be further reduced.

In an ink jet recording apparatus according to a third aspect, in the first or second aspect, the recording control means controls the ink jet head to eject ink during both the forward movement and the backward movement of the carriage. Further, the recording control means determines an ejection start position for setting the ejection start position of the inkjet head corresponding to the image recording area of the recording medium for each pass of the forward or backward movement of the carriage. Further comprising means,
The target stop position setting means determines the target stop position for each pass based on the injection end position of the pass and the injection start position of the next pass. is there.

  In the case of performing so-called bidirectional printing in which ink is ejected in both forward and backward movements of the carriage, if the target stop position determined from the ejection end position of each pass is close to the ejection start position of the next pass, There is a possibility that the acceleration distance (running distance) in the path of (1) cannot be secured above a certain level. Therefore, in the present invention, the target stop position of each pass is determined in consideration of the injection start position of the next pass, thereby securing the acceleration distance of the next pass to a certain level or more.

In the ink jet recording apparatus according to a fourth aspect of the present invention, in any one of the first to third aspects, the target stop position setting means sets the target stop position to the downstream side in the movement direction by the stop allowable range setting means. It is set to the center position of the extended stop allowable range .

  The ink jet recording apparatus according to a fifth aspect of the present invention is the ink jet recording apparatus according to any one of the first to fourth aspects, wherein the recording control unit is configured to detect the carriage based on a detection result of the position detecting unit when the carriage is stopped. It further comprises determination means for determining whether or not the vehicle has stopped within the stop allowable range, and when the determination means determines that the carriage has not stopped within the stop allowable range, the carriage is moved again to It is characterized by stopping within a stop allowable range.

  In each pass, when the carriage does not stop within the allowable stop range, the carriage is moved to stop within the allowable stop range (retry), and the next pass is started by performing the above retry. As the number of retries increases, the recording speed decreases. In this case, it is very significant to reduce the number of retries by applying the present invention and expanding the allowable stop range within a range that does not cause problems such as interference with other members.

  According to the present invention, as the target stop position of the carriage is set to the upstream side in the movement direction, the stop allowable range set for the target stop position is expanded to the downstream side in the movement direction of the carriage. The frequency of stopping exceeding the stop allowable range decreases, and unnecessary stop operation retries are reduced.

1 is a schematic plan view of an ink jet printer according to an embodiment. It is a block diagram which shows the control system of an inkjet printer. It is a figure which shows the movement (pass) of the carriage at the time of image recording. It is a figure explaining the basic control of a carriage stop. It is a figure explaining the change of the stop allowable range according to an image recording area. It is a figure explaining the change of the stop allowable range according to recording mode. It is a figure explaining the determination method of the target stop position in case recording image widths differ between passes. It is a figure explaining the change of the stop allowable range according to the image recording area based on a change form. It is a figure explaining the determination of the target stop position based on the size of a recording paper based on another modification.

  Next, an embodiment of the present invention will be described. The present embodiment is an example in which the present invention is applied to an ink jet printer that includes an ink jet head that ejects ink droplets onto a recording paper 100.

  First, a schematic configuration of the inkjet printer 1 of the present embodiment will be described. FIG. 1 is a schematic plan view of an inkjet printer 1 according to the present embodiment. FIG. 2 is a block diagram showing a control system of the ink jet printer 1.

  As shown in FIGS. 1 and 2, the printer 1 includes a carriage 2 configured to reciprocate along a predetermined scanning direction (left-right direction in FIG. 1), and an inkjet head 3 mounted on the carriage 2. , A recording mechanism 100 (conveying means) that conveys the recording paper 100 that is a recording medium in a conveying direction that intersects (in this case, orthogonal) to the scanning direction, a maintenance unit 5 that performs maintenance of the inkjet head 3, and a printer 1 A control device 6 for controlling the entire system is provided.

  The carriage 2 is configured to be able to reciprocate along two guide shafts 17 extending in parallel with the scanning direction (left-right direction in FIG. 1). An endless belt 18 is connected to the carriage 2. When the endless belt 18 is driven to travel by the carriage drive motor 19, the carriage 2 moves in the scanning direction as the endless belt 18 travels. It has become. The printer 1 is provided with a linear encoder 10 having a large number of light transmitting portions (slits) arranged at intervals in the scanning direction. On the other hand, the carriage 2 is provided with a transmissive photosensor 11 (position detecting means) having a light emitting element and a light receiving element. The printer 1 can recognize the current position in the scanning direction of the carriage 2 from the count value (number of detections) of the light transmitting portion of the linear encoder 10 detected by the photosensor 11 while the carriage 2 is moving. .

  An ink jet head 3 is mounted on the carriage 2. The inkjet head 3 includes a large number of nozzles 30 on the lower surface (the surface on the other side of the paper surface of FIG. 1; hereinafter also referred to as an ink ejection surface). In FIG. 1, the nozzles 30 are shown to be quite large for the sake of clarity in the drawing, and the number of nozzles 30 shown is also small, but in practice it has a very small opening. A large number of nozzles 30 are formed. The ink jet head 3 is configured to eject ink supplied from an ink cartridge (not shown) from a large number of nozzles 30 onto a recording paper 100 that is transported downward (conveying direction) in FIG. ing.

  The transport mechanism 4 includes a transport roller 12 disposed on the upstream side in the transport direction with respect to the inkjet head 3 and a paper discharge roller 13 disposed on the downstream side in the transport direction with respect to the inkjet head 3. The transport roller 12 and the paper discharge roller 13 are rotationally driven in synchronization by the transport motor 14. The transport mechanism 4 transports the recording paper 100 from the upper side of FIG. 1 to the ink jet head 3 with a predetermined feed amount by the transport roller 12, and images, characters, and the like are recorded by the ink jet head 3 by the paper discharge roller 13. The recorded recording paper 100 is discharged downward in FIG.

  The maintenance unit 5 is disposed at a position (maintenance position) separated from the conveyance area of the recording paper 100 on one side in the scanning direction (right side in FIG. 1). The maintenance unit 5 includes a suction cap 20 that contacts the lower surface of the inkjet head 3 (an ink ejection surface with the nozzles 30 opened) and covers the plurality of nozzles 30; a suction pump 21 connected to the suction cap 20; and an inkjet head And a wiper 22 for wiping off ink adhering to the ink ejection surface 3.

  Then, the maintenance unit 5 brings the suction cap 20 into close contact with the ink ejection surface of the inkjet head 3 and operates the suction pump 21 in a state where the nozzle 30 is covered with the suction cap 20. Dust, bubbles, thickened ink, and the like existing in the ink flow path are sucked and discharged from the opening of the nozzle 30 together with the ink (suction purge). Further, after the suction purge, the waste ink adhering to the ink ejection surface is wiped off with the wiper 22.

  2 includes, for example, a central processing unit (CPU) that is a central processing unit, and a ROM (Read Only Memory) in which various programs and data for controlling the overall operation of the printer 1 are stored. And a microcomputer including a RAM (Random Access Memory) that temporarily stores data to be processed by the CPU, and the program stored in the ROM is executed by the CPU, as described below. Various controls are performed. Alternatively, the control device 6 may be a hardware device in which various circuits including an arithmetic circuit are combined.

  The control device 6 includes a head control unit 42 that controls the ink ejection operation of the inkjet head 3, a carriage control unit 43 that controls a carriage drive motor 19 that drives the carriage 2 in the scanning direction, a transport roller 12, and a discharge roller. And a conveyance control unit 44 that controls the conveyance motor 14 that drives the recording motor 13. The recording control unit 40 controls the inkjet head 3, the carriage drive motor 19, and the transport motor 14 of the transport mechanism 4 based on the image data input from the PC 50, which is an external device, and records on the recording paper 100. To do. More specifically, the recording paper 100 is transported at a predetermined feed amount by the transport roller 12, and the carriage 2 carrying the inkjet head 3 is moved once in the scanning direction (forward or backward movement: also called a pass). Are alternately performed and ink is ejected from the nozzle 30 of the inkjet head 3 toward the recording paper 100 during one pass, thereby recording an image on the recording paper 100. In addition, so-called bi-directional printing is possible in which ink is ejected from the ink-jet head 3 during both forward and backward movements of the carriage 2 performed with one transport operation of the recording paper 100 performed by the transport mechanism 4.

  In the present embodiment, the recording control unit 40 can selectively execute two recording modes having different resolutions (a high resolution recording mode and a low resolution recording mode) in accordance with a mode selection signal input from the PC 50. It has become. More specifically, when the high resolution recording mode is selected, the recording control unit 40 reduces the one-time feed amount by the transport roller 12 and the movement of the carriage 2 in one pass when compared with the low resolution recording mode. Reduce the speed. Thereby, the dot interval is narrowed in each of the transport direction and the scanning direction, and image recording with high resolution is performed.

  Furthermore, the control device 6 includes a maintenance control unit 41 that controls the suction pump 21 of the maintenance unit 5, the lifting mechanism of the suction cap 20, and the like, and controls a series of maintenance operations of the maintenance unit 5 including suction purge. Yes.

  Next, the control of the inkjet head 3 and the carriage 2 by the head control unit 42 and the carriage control unit 43 will be described in more detail. FIG. 3 is a diagram showing movement (pass) of the carriage 2 during image recording. In the following description, the upstream side and the downstream side in the movement direction of the carriage 2 in one pass are referred to as the inner side and the outer side, respectively.

  As shown in FIG. 3, a maximum image recording range, which is a maximum range in which the inkjet head 3 mounted on the carriage 2 ejects ink, is set in advance. This maximum image recording range depends on the width of the maximum size of the recording paper 100 that can be used by the printer 1 (for example, A3 paper having a large width when both A4 and A3 can be used). It is determined and stored in advance in a storage unit such as a ROM of the control device 6. FIG. 3 shows an example of a printer capable of so-called borderless printing in which an image is recorded over the entire width of the recording paper 100. In order to land ink on the entire width of the paper, the maximum image recording range is shown. Is set in a range slightly wider on both sides in the scanning direction than the paper width, and ink is ejected beyond the edge of the recording paper 100 when performing borderless printing. In the case of a printer that does not perform borderless printing, the same range as the paper width of the recording paper 100 or a range narrower by a certain margin than that is set as the maximum image recording range.

  As shown in FIG. 2, the head control unit 42 includes an ejection start position determination unit 45 and an ejection end position determination unit 46. The ejection start position determination unit 45 and the ejection end position determination unit 46 are based on the image data input from the PC 50, and the ejection start position P1 and the ejection end position of the inkjet head 3 corresponding to the image recording area for each pass. Each P2 is determined. For example, when a rectangular image as shown in FIG. 3 is formed on the recording paper 100, the ejection start position P1 of the rightward path in the figure is the left end of the image recording area 101, and the ejection end position P2 is an image. It becomes the right end of the recording area 101.

  The carriage control unit 43 controls the carriage drive motor 19 based on the position information of the carriage 2 detected by the photosensor 11 (position detection means), and starts acceleration and ink ejection during each pass. The carriage 2 is caused to travel at a constant speed (during recording) and to decelerate and stop at the end (before reversal).

  Here, among the control of the carriage 2 performed by the carriage control unit 43, the stop control especially at the time of reciprocal reversal will be described in detail. FIG. 4 is a diagram for explaining basic control of carriage stop. As shown in FIG. 2, the carriage control unit 43 has a target stop position setting unit 47 that determines a target stop position (Ps in FIG. 4) of the carriage 2 at the time of reciprocal reversal, and the determined target stop position Ps. The carriage drive motor 19 is controlled so that the carriage 2 stops.

  In the present embodiment, when the carriage 2 reaches the above-described injection end position P2, the carriage 2 is quickly decelerated and stopped. That is, the target stop position Ps of the carriage 2 is determined according to the ejection end position P2. For example, when recording an image over the entire maximum image recording range, the target stop position is set to Ps0, and the carriage is moved from the right end of the maximum image recording range to the target stop position Ps0 according to the deceleration profile 60 indicated by the broken line in the figure. 2 is decelerated. On the other hand, when the image recording area 101 is in the center in the width direction of the recording paper 100 instead of recording an image over the entire maximum image recording range as shown in FIG. 4, the ejection end position P2 is the maximum image recording range. It is on the inner side (upstream side in the movement direction of the carriage 2) by a distance B from the end of. The target stop position Ps at this time is the stop position Ps1 when the vehicle is decelerated from the injection end position P2 according to the deceleration profile 61 indicated by the solid line in FIG. That is, the target stop position Ps1 corresponding to the image recording area in FIG. 4 is set inward by the distance B from the target stop position Ps0 corresponding to the maximum image recording range.

  The target stop position Ps0 corresponding to the maximum image recording area is a position farthest outside the carriage 2 (limit stop position) among the target stop positions determined by the target stop position setting unit 47. The limit stop position Ps0 is set in advance based on the type of paper used in the printer 1, the presence or absence of a borderless printing function, and the like, and the target stop position setting unit 47 stores (holds) the limit stop position Ps0. .

  Meanwhile, the carriage 2 is controlled by the carriage control unit 43 so as to stop at the target stop position Ps determined by the target stop position setting unit 47, but the actual stop position is completely set to the target stop position Ps. It is difficult to match. However, if the vehicle stops largely deviating from the target stop position Ps, there is a risk of interference with other members and mechanisms set outside the normal movement range of the carriage 2 during recording. For example, in the present embodiment, the maintenance unit 5 is disposed outside the area facing the recording paper 100. However, when the carriage 2 has moved outside the target stop position Ps, the maintenance unit 5 is disposed. There is a possibility that the maintenance unit 5 may malfunction due to contact with a member or a mechanism for operating 5. In addition, if the vehicle is largely shifted inward with respect to the target stop position Ps, the distance from the actual stop position to the injection start position P1 of the next pass is shortened, and the acceleration distance in the next pass may not be secured. There is.

  Therefore, the carriage control unit 43 includes a stop allowable range setting unit 48 for setting the stop allowable range of the carriage 2 (range A in FIG. 4) including the target stop position Ps described above for each pass, and the carriage 2. And a determination unit 49 that determines whether the carriage 2 has stopped within the allowable stop range based on a signal (detection result) of the photosensor 11 that detects a position in the scanning direction. When the determination unit 49 causes the carriage 2 to stop within the stop allowable range, the carriage control unit 43 promptly starts the next pass. On the other hand, when the determination unit 49 determines that the carriage 2 has not stopped within the allowable stop range, the carriage control unit 43 slightly moves the carriage 2 to stop within the allowable stop range (retry of the stop operation). ) To start the next pass.

  Here, if the stop allowable range is not set strictly (narrowly) under certain conditions, problems such as interference with other members described above and insufficient acceleration distance occur. However, under other conditions, it is particularly severe. It may not be necessary to set. Even under such conditions, if the allowable stop range is set narrow, retry of the stop operation is unnecessarily performed. Therefore, in such a case, it is desirable to widen the stop allowable range beyond the range A shown in FIG. 4 to loosen the accuracy of stop control and reduce unnecessary retries. Hereinafter, the change of the allowable stop range will be described with two specific examples.

(1) Change of Allowable Stop Range According to Image Recording Area FIG. 5 is a diagram for explaining change of the allowable stop range according to the image recording area 101. As shown in FIG. 5, when an image is recorded in the center of the recording paper 100 (the image recording area 101 is set), the ejection end position P2 is located inside the end of the maximum image recording range. Accordingly, the target stop position Ps1 set according to the injection end position P2 is also set inside the limit stop position Ps0 corresponding to the maximum image recording range. Accordingly, the distance (margin) to other members and the like arranged outside the moving range of the carriage 2 at the time of recording increases, so that no particular problem arises even if the stop allowable range is extended outside.

  Accordingly, the stop allowable range setting unit 48 sets the stop allowable range as the target stop position Ps corresponding to the injection end position P2 of each pass is on the inner side and the distance (margin length) to the limit stop position Ps0 is larger. Widen outwards. More specifically, as shown in FIG. 5, when the injection end position P2 is only a distance B from the end of the maximum image recording range, the target stop position Ps1 set by the target stop position setting unit 47, The margin length with the limit stop position Ps0 corresponding to the maximum image recording range is also the distance B. Then, the stop allowable range setting unit 48 expands the stop allowable range including the target stop position Ps1 outward from the initial range A by the margin length B, and changes the range to A + B.

  As a result, the frequency at which the carriage 2 stops beyond the stop allowable range is reduced, and the number of times of retry of the stop operation is reduced. Further, it calculates how far the target stop position Ps of the carriage 2 in each pass is from the limit stop position Ps0 (allowance length B), and extends the stop allowable range as it is to the downstream side by this allowance length B. Thus, the allowable stop range is maximized within a range in which interference with other members does not occur, and the number of retries can be further reduced.

  Note that by expanding the stop allowable range to the outside, the number of retries when the carriage 2 is stopped by moving outward with respect to the target stop position Ps is reduced, but when the carriage 2 is shifted inward with respect to the target stop position Ps and stopped. The number of retries does not change. On the other hand, regarding the deviation of the actual stop position from the target stop position Ps when the carriage 2 is controlled to stop at the target stop position Ps, the occurrence frequency (probability) is the same between the inside and the outside. It is thought that it does not change. Accordingly, the stop allowable range setting unit 48 further changes the target stop position Ps to Ps2 outside the initially set Ps1 in response to widening the stop allowable range to the outside. The inner stop allowable range is increased, and the vehicle is decelerated by the deceleration profile 62 indicated by the thick line in FIG. As a result, the number of retries when the position deviates inward from the target stop position Ps can also be reduced.

  As described above, since the carriage 2 is considered to be displaced with the same probability inside and outside the target stop position Ps, the target stop position Ps2 after the change is as shown in FIG. It is preferable to set the central position of the stop allowable range (A + B) that spreads outward, and to make the widths of the stop allowable range equal to the inner range and the outer range with respect to the target stop position Ps2. As a result, the number of retries can be further reduced.

(2) Change of Allowable Stop Range According to Recording Mode As described above, the pass after reversal is within the stop allowable range within the target stop position Ps (upstream side in the movement direction of the carriage 2). If the stop position shifts further inward than this range, the landing position shift due to insufficient acceleration may occur and print quality may deteriorate.

  However, this deterioration in print quality is a serious problem in the high-resolution recording mode, but in the low-resolution recording mode that originally does not require such a high print quality, it does not become a big problem unless the landing position deviation is very large. Therefore, the range within the stop allowable range inside the target stop position Ps is changed according to the resolution of the recording mode.

  FIG. 6 is a diagram for explaining the change of the stop allowable range according to the recording mode. When the high-resolution recording mode is selected, the stop allowable range setting unit 48 does not change the stop allowable range A of FIG. 6 which is initially set so as not to cause insufficient acceleration in the pass after reversal. The range inside the stop position Ps is kept small. As a result, the next pass is always started from the state of stopping near the target stop position Ps, and the acceleration distance is ensured to be equal to or greater than a certain value, so that it is possible to prevent the print quality from being deteriorated due to insufficient acceleration.

  On the other hand, when the low-resolution recording mode is selected, a slight decrease in print quality is not a significant problem. Therefore, as shown in FIG. 6, the target stop position Ps in the stop allowable range is smaller than that in the high-resolution recording mode. The inner range is further expanded inward by a predetermined distance C, and the stopping accuracy is relaxed. As a result, the frequency with which the carriage 2 stops beyond the stop allowable range is reduced, and unnecessary retries are reduced. Here, if the predetermined distance C is too large, the acceleration distance in the pass after reversal is insufficient, and there is a possibility that a large landing position shift may occur even when the low resolution recording mode is selected. The predetermined distance C is determined within a range in which landing position deviation does not become a problem when the low resolution recording mode is selected.

  The main purpose of providing the permissible range outside the target stop position Ps in the permissible stop range is, as described above, other members installed on the outside (downstream side in the carriage movement direction). Since this is a matter to be prevented regardless of the recording mode, the width of the outer permissible range is made equal in both recording modes.

  Further, as described in (1) above (see FIG. 5), when the stop allowable range is expanded outward according to the image recording range 101, the limit allowable position inside the stop allowable range is also shifted to the downstream side. The entire allowable stop range including the target stop position Ps may be shifted outward. As a result, the range inside the target stop position Ps is increased to some extent to reduce unnecessary retries, and a decrease in print quality due to landing position deviation can be prevented at a higher level.

  Next, the determination of the target stop position Ps by the target stop position setting unit 47 will be supplemented a little. As shown in FIGS. 3 to 6, when the width of the image recording area 101 does not change, the injection end position P2 of the pass before reversal and the injection start position P1 of the pass after reversal are the same position. Become. If the deceleration distance to the stop required in the pass before reversal and the acceleration distance to reach the constant speed required in the pass after reversal are equal, the target stop position Ps is The determination may be made in consideration of only the injection end position P2 of the pass.

  However, actually, the width of the image recording area 101 may be different between the pass before reversal and the pass after reversal. For example, as shown in FIG. 7, the injection start position P1 of the pass after reversal is reversed. It may be located outside the injection end position P2 of the previous pass. In this case, the target stop position Ps corresponds to the injection end position P2 of the path before reversal corresponding to the injection start position P1 of the path after reversal in order to secure the acceleration distance of the path after reversal to a certain value or more. It is necessary to set the position Ps ″ further outside the corresponding stop position Ps ′. In this case, the carriage 2 decelerates with the deceleration profile 63 shown in FIG. Thus, it is preferable to determine the target stop position Ps of each pass not only based on the injection end position P2 of the pass but also the injection start position P1 of the next pass.

  Next, modified embodiments in which various modifications are made to the embodiment will be described. However, components having the same configuration as in the above embodiment are given the same reference numerals and description thereof is omitted as appropriate.

1] The change of the stop allowable range according to the image recording area (see FIG. 5) described in (1) of the above embodiment is so-called bi-directional in which ink is ejected in both forward and backward movements of the carriage 2. Although it was applied to printing, ink was ejected in a one-way pass, while in the reverse direction, the carriage 2 moved (returned) and did not eject ink, so-called one-way printing. It can be applied even if it exists.

  In the case of unidirectional printing, the carriage 2 only returns in the pass after the ink is ejected and after the reversal, and the actual stop position is relative to the target stop position Ps in the ink ejected pass. Even if it shifts inward, no particular problem occurs. Therefore, unlike FIG. 5 of the above embodiment, as shown in FIG. 8, there is no need to provide a stop allowable range on the inner side of the target stop position Ps in the path for ejecting ink, and it is provided only on the outer side. (A range indicated by A ′ in the figure). In this case, the stop allowable range is changed to a range of A ′ + B by expanding the stop allowable range to the outside by the margin length B.

  In a pass (return pass) where ink is not ejected, the target stop position Ps is determined according to the ejection start position P1 of the next pass. At this time, even if the carriage 2 is moved at a high speed in the return path, the stop allowable range is extended outward by the margin length from the target stop position Ps to the limit stop position Ps0, so that the stop is within the stop allowable range. And the recording speed is increased.

2] In a printer capable of using a plurality of types of recording papers having different widths (for example, A3 paper and A4 paper), the ejection start position P1 and the ejection end position P2 of each pass are conveniently determined according to only the type of the recording paper 100. You may decide to. For example, as shown in FIG. 9, when the maximum image recording area and the limit stop position Ps0 are set according to the width of the large recording sheet 100A, the small recording sheet 100B is used from the PC 50. The image recording area 101 is uniformly set to a range D in the figure on the assumption that borderless printing is performed over the entire width direction of the recording paper 100B without referring to the input image data, and ejection starts from the range D The position P1, the injection end position P2, and the target stop position Ps are determined.

  In other words, one target stop position Ps is set for each of a plurality of types of recording sheets 100 regardless of the actual image recording area, and the margin length B to the limit stop position Ps0 is calculated accordingly. . According to this, the target stop position Ps and the margin length B can be easily determined, and the number of retries can be reduced while simplifying the stop control.

3] In the above embodiment, when the allowable stop range is expanded outward, the target stop position Ps is also changed accordingly. However, the change of the target stop position Ps is not essential. Even if the stop allowable range is widened outwardly, the frequency at which the actual stop position of the carriage 2 is shifted outward from the stop allowable range is reduced, which leads to a decrease in the number of retries.

4] In the above embodiment, as shown in FIG. 5, the stop allowable range is expanded outward by the margin length B from the limit stop position Ps0 to the target stop position Ps. The length B need not be set, and may be less than the margin length B.

5] Other members and the like that may interfere with the carriage 2 considered in setting the range outside the target stop position Ps of the allowable stop range are related to the maintenance unit 5 exemplified in the above embodiment. It is not limited to members. That is, any member that does not interfere when the carriage 2 is reciprocating within a normal range during image recording, but may interfere when stopped outside the permissible stop range should be used. Any member can be applied.

DESCRIPTION OF SYMBOLS 1 Inkjet printer 2 Carriage 3 Inkjet head 4 Conveyance mechanism 11 Photo sensor 40 Recording control part 45 Injection start position determination part 46 Injection end position determination part 47 Target stop position setting part 48 Stop permissible range setting part 49 Judgment part 100 Recording paper 101 Image Recording area

Claims (5)

A carriage that reciprocates in a predetermined scanning direction;
Transport means for transporting a recording medium in a transport direction that intersects the scanning direction;
An inkjet head mounted on the carriage and ejecting ink onto the recording medium while reciprocating in the scanning direction together with the carriage;
Position detecting means for detecting a position of the carriage in the scanning direction;
The recording medium is controlled by controlling reciprocating movement of the carriage based on position information detected by the position detecting means, and ejecting ink from the ink jet head at least one of forward movement and backward movement of the carriage. A recording control means for recording an image on
The recording control means includes
Determination of the ejection end position for setting the ejection end position of the inkjet head corresponding to the image recording area of the recording medium for each pass of the forward or backward movement of the carriage that ejects ink from the inkjet head Means,
Target stop position setting means for setting a target stop position of the carriage after reaching the injection end position for each pass, according to the injection end position;
Similarly, it comprises a stop allowable range setting means for setting a stop allowable range of the carriage including the target stop position for each pass.
Further, the stop allowable range setting means expands the stop allowable range to the downstream side in the carriage movement direction as the target stop position corresponding to the injection end position is on the upstream side in the carriage movement direction .
In response to the stop allowable range setting means expanding the stop allowable range to the downstream side in the carriage movement direction, the target stop position setting means sets the previously set target stop position of the carriage to the carriage. The inkjet recording apparatus is characterized by being changed to the downstream side in the moving direction . The target stop position setting means stores a limit stop position corresponding to the maximum image recording range in the scanning direction, which is the target stop position farthest downstream in the movement direction of the carriage,
The allowable stop range setting means calculates a margin length, which is a distance between the target stop position determined by the target stop position setting means and the limit stop position, for each pass. by the length, the ink jet recording apparatus according to claim 1, characterized in that widening the stop allowable range in the direction of movement downstream side of the carriage. The recording control means controls the ink jet head both in the forward movement and in the backward movement of the carriage to eject ink;
The recording control means is an ejection start position determining means for setting an ejection start position of the ink jet head corresponding to an image recording area of the recording medium for each pass of the forward or backward movement of the carriage. Further comprising
The target stop position setting means determines the target stop position for each pass based on the injection end position of the pass and the injection start position of the next pass. The ink jet recording apparatus according to 1 or 2. The target stop position setting means sets the target stop position at a center position of the stop allowable range widened downstream in the movement direction by the stop allowable range setting means. An ink jet recording apparatus according to any one of the above. The recording control means includes
Determination means for determining whether or not the carriage has stopped within the allowable stop range based on a detection result of the position detection means when the carriage has stopped;
5. If the determination means determines that the carriage has not stopped within the allowable stop range, the carriage is moved again to stop within the allowable stop range. 2. An ink jet recording apparatus according to 1.

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