Patent Grant
8789909
1. Field of the Invention
The present invention relates to an ink jet recording apparatus in which a carriage configured to move along a recording medium is equipped with a detection unit capable of detecting whether the recording medium is in an abnormal state by detecting a distance to the recording medium.
2. Description of the Related Art
As one type of recording apparatus such as a printer, a facsimile, a copying machine for recording an image based on image information on a sheet-shaped recording medium such as paper, there is an ink jet recording apparatus which records an image by discharging ink from a recording head onto a recording medium. A typical ink jet recording apparatus is a serial-type ink jet recording apparatus including a recording head mounted on a carriage capable of reciprocating in a main scanning direction intersecting with a conveying direction of recording medium, and performing a recording operation by discharging ink from the recording head in synchronization with a movement of the carriage. In this serial-type recording method, recording on an entire recording medium is performed by alternately repeating a recording operation of recording one line while the carriage is being moved, and a conveyance operation of conveying the recording medium by a predetermined pitch. Examples of recording medium include a cut sheet divided into a predetermined size, and a continuous sheet such as roll paper. A recording apparatus using a continuous sheet cuts the continuous sheet at the rear end of a recorded image of a predetermined amount by a cutter unit, and discharges the portion of the sheet with the image recorded thereon.
If abnormal conveyance such as sheet uplift occurs at the time of conveyance of a recording medium through a recording unit, this may result in incorrect recording on the recording medium. For example, some types (characteristics) of recording medium or some conditions of ambient environment such as a temperature and humidity may cause a cutter unit to be caught by a recording medium when the cutter unit cuts the recording medium, which may lead to sheet uplift, then resulting in generation of a scrape between the recording head and the recording medium. If the sheet uplift is significant enough to apply a large load to the carriage and cutter, the recording operation is immediately stopped to prevent the recording head from being heavily damaged. However, in some cases, sheet uplift only slightly increases the load applied to the carriage and the cutter, while scrapes of the recording head are being accumulated. In such a case, this abnormality cannot be distinguished from a load fluctuation in a normal cutting operation, so that the scrape of the recording head cannot be detected. Then, if the recording head is repeatedly damaged from the scrapes, not only correct recording may become impossible but also the recording head may be broken.
Japanese Patent Application Laid-Open No. 2005-015132 discusses a technique of determining an abnormality in a recording medium being conveyed based on a detection result about the width of the recording medium and the distance from the recording medium to a recording head with use of a distance measurement sensor capable of detecting the distance from the recording head on a carriage to the recording medium. Further, Japanese Patent Application Laid-Open No. 2004-074710 discusses a technique of detecting the distance to a recording medium and the width of the recording medium with use of a sensor mounted on a carriage to detect an abnormality in the recording medium being conveyed based on the detection result.
However, since the technique discussed in Japanese Patent Application Laid-Open No. 2005-015132 is a method of detecting a flap on a tractor apparatus on which the edges of a continuous sheet on the both sides are placed, this technique can detect only a sheet uplift state at the edges of the sheet on the both sides, and therefore cannot detect a sheet uplift state at the center position of the sheet. On the other hand, the technique discussed in Japanese Patent Application Laid-Open No. 2004-074710 detects an abnormal state at an arbitrary position or a plurality of positions of a sheet with use of the distance measurement sensor mounted on the carriage. Then, this technique immediately determines that the conveyance state is abnormal when the detection result exceeds a predetermined range. These features of the method discussed in Japanese Patent Application Laid-Open No. 2004-074710 lead to the following problems. When an abnormal state such as sheet uplift is searched at a plurality of positions or in the entire region of a sheet prior to a printing operation, a sheet having a large size increases a time spent on detection movement of the carriage, thereby reducing the throughput even when the conveyance is in a normal state. Further, even though detection is performed by moving the carriage during cutting of a sheet to prevent a reduction in the throughput, since the sheet changes its posture relative to the carriage, output of the sensor fluctuates, thereby reducing the detection accuracy. Further, although sheet uplift may be alleviated through a sheet push-out operation, sheet uplift is searched at a position where the sheet behaves differently from the time of printing, thereby reducing the detection accuracy. As a result, even conveyance that is not abnormal may be determined as a conveyance failure.
The present invention is directed to an ink jet recording apparatus using an easy method for preventing a recording failure due to an abnormal state by accurately detecting whether a conveyance state of a recording medium is abnormal while maintaining throughput of a recording operation.
According to an aspect of the present invention, an ink jet recording apparatus includes a recording head configured to discharge ink onto a recording medium, a carriage on which the recording head is mounted and which is configured to make a reciprocating movement, a cutter unit mounted on the carriage and configured to cut the recording medium, a detection unit mounted on the carriage and configured to detect a distance to the recording medium, and a control unit configured to control an operation of the recording apparatus. The ink jet recording apparatus includes a first process for detecting an amount of a change in the distance to the recording medium by the detection unit when the recording medium is cut by the cutter unit, and a second process for detecting the distance to the recording medium by the detection unit while the cutter unit is retracted if the change amount equal to or more than a predetermined value is detected in the first process. The control unit determines that the state of the recording medium is abnormal when the distance to the recording medium detected in the second process is equal to or less than a predetermined value.
Further features and aspects of the present invention will become apparent from the following detailed description of exemplary embodiments with reference to the attached drawings.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the invention and, together with the description, serve to explain the principles of the invention.
Various exemplary embodiments, features, and aspects of the invention will be described in detail below with reference to the drawings.
A platen 107 is disposed at a position opposite to the recording head 103 for supporting a recording medium 106 on which an image is recorded. The recording medium 106 is conveyed on the platen 107 by a not-illustrated conveyance roller. The arrow Y indicates a conveyance direction (sub-scanning direction) of the recording medium 106. Further, the arrow Z indicates a direction perpendicular to an XY plane defied by the X direction and the Y direction. During a recording operation, an image is formed by discharging ink from the recording head 103 onto the recording medium 106 while the carriage 101 is driven to scan in the X direction on the recording medium 106 conveyed onto the platen 107 by the conveyance roller. An image is recorded throughout the entire region of the recording medium 106 by alternately repeating recording of one line with use of the recording head 103 and conveyance of the recording medium 106 with use of the conveyance roller by a predetermined pitch. After image recording is completed, the recording medium 106 is conveyed to a cutting position of the platen 107 on the downstream side in the conveyance direction by the conveyance roller.
For example, as illustrated in
A control unit 500 is disposed at the main body of the recording apparatus. The control unit 500 is constituted by a controller including a central processing unit (CPU), a memory, an input/output (I/O) circuit, and others. This control unit 500 controls operations of a drive motor and other various devices according to a control program stored in an internal memory in advance. Thus, an image is recorded onto the recording medium 106 by controlling recoding operations of the recording medium 106 (including, for example, a sheet feed conveyance operation and a cutting operation), and controlling drive of the recording head 103 based on image data. Further, the control unit 500 controls a detection operation of the detection unit 102, which will be described later, and controls other overall operations of the recording apparatus, and timing therefor as well.
The width of light irradiated from the infrared LED 201 is adjusted by an opening thereof to be optimized for formation of an illuminated surface about 4 to 5 mm in diameter on the measurement surface located at the reference position. The two phototransistors 203 and 204 have a light sensitivity in a wavelength range from visible light to infrared light. The phototransistors 203 and 204 are arranged so that optical axes of light beams that the phototransistors 203, 204 receive become parallel to a reflection axis of the infrared LED 201 when the measurement surface is located at the reference position. More specifically, the phototransistor 203 and 204 are arranged so that the light receiving axis of the phototransistor 203 is located at a position deviated +2 mm in the X direction and +2 mm in the Z direction from the reflection axis, and the light receiving axis of the phototransistor 204 is located at a position deviated −2 mm in the X direction and −2 mm in the Z direction from the reflection axis. When the measurement surface is located at the reference position, the intersection point between the optical axis of light irradiated from the infrared LED 201 and the measurement surface coincides with the intersection point between the optical axis of light irradiated from the visible LED 205 and the measurement surface, and the regions of light beams that the two phototransistors 203 and 204 receive are formed so as to sandwich this intersection point. Further, a spacer about 1 mm thick is disposed between the two phototransistors 203 and 204 so as to prevent light beams that the phototransistors 203 and 204 receive from wrapping around each other. Each of the phototransistors 203 and 204 also has an opening to limit a range where incoming light enters. The size of this opening is optimized so that the phototransistors 203 and 204 can receive only light reflected from a range 3 to 4 mm in diameter on the measurement surface at the reference position.
The visible LED 205 is an monochromatic visible LED having a green light emission wavelength (about 510 nm to 530 nm), and is disposed so as to correspond to the sensor center axis 202. The visible LED 206 is a monochromatic visible LED having a blue light emission wavelength (about 460 nm to 480 nm) and, as illustrated in
In the above-described positional arrangement of the phototransistors 203 and 204, the centers of the light receiving regions 402 and 403 are measured as points offset from the center of the illuminated region 401. Therefore, the areas where the illuminated region 401 and the light receiving regions 402 and 403 overlap are significantly changed even by a slight change in the distance between the sensor 102 and the measurement surface, compared to the arrangement in which the centers of the regions 402 and 403 are measured as points located on the center (sensor center axis) 202.
Referring to
Referring to
Referring to
In this way, the outputs of the two phototransistors 203 and 204 vary according to the distance between the detection unit 102 and the measurement surface. The interval between the positions where the outputs of the two phototransistors 203 and 204 are maximized is determined based on the relative offset amount between the phototransistors 203 and 204 in the Z direction, the inclination degrees of the phototransistors 203 and 204 relative to the measurement surface, and the inclination degree of the infrared LED 201 relative to the measurement surface. This positional arrangement is optimized based on the width of a desired measurement range. Upon acquisition of the outputs of the two phototransistors 203 and 204 varying according to the distance to the recording medium 106, the CPU 301 calculates a distance coefficient L based on the two outputs.
The distance coefficient L indicated in
L=(Va/Vb)×α EXPRESSION (1)
where α is a predetermined constant number determined for each apparatus. The distance coefficient L is a coefficient varying according to the distance between the sensor 102 and the measurement surface, and has a smallest value when the output of the phototransistor 203 is maximized (the reference position −1 mm) and a largest value when the output of the phototransistor 204 is maximized (the reference position +1 mm). It is desirable in consideration of the characteristic of the distance coefficient L that the measurement range is within the range of the peaks of the two phototransistors 203 and 204. In the present exemplary embodiment, the measurement range of the detection unit 102 is from the reference position −1 mm to the reference position +1 mm.
After the acquisition of the distance coefficient L by the arithmetic processing of the CPU 301, a distance reference table stored in the memory 306 is read out.
With use of the above-described detection unit 102, it is possible to detect the distance from the detection unit 102 to the measurement surface and a change in the distance. When the measurement surface is the recording surface of the recording medium 106, it is possible to detect the distance from the detection unit 102 to the recording medium 106 and a change in this distance. Further, it is possible to detect the width (the width in the carriage movement direction) and the thickness of the recording medium 106 by detecting the distance to the platen 107 and the recording medium 106 on the platen 107 and a change therein while the carriage 101 is moved. Then, it is possible to detect the state of the posture of the recording medium 106 while being conveyed, such as sheet uplift, by detecting a change in the distance to the recording medium 106 and the change amount. In this way, the detection unit 102 can utilize the distance to the measurement surface for various purposes by detecting a change therein, and can function as a multipurpose sensor.
The detection unit 102 is different from a commonly-used distance measurement sensor in terms of the following points. As described above, it is possible to detect the distance to the measurement surface as the recording surface of the recording medium 106 with use of the detection unit 102. If two light receiving elements and a light emitting element are disposed on a same plane as in a commonly-used distance measurement sensor, the detection is subject to an influence of blurs of the illuminated region and the light receiving regions due to variation in the intensity of light irradiated to a measurement object and a change in the distance as the characteristics of diffusion light. As a result, a problem arises in that the slope of the line until the output peak and the slope of the line after the output peak become asymmetrical in the output curve of each light receiving element, whereby the accuracy of a distance measurement sensor is deteriorated under the influence of a position where the sensitivity is low. On the other hand, according to the detection unit 102 in the present exemplary embodiment, the symmetry between the rising part and the falling part of the output curve is improved, thereby enabling accurate distance detection.
Generally, recording media have different reflection characteristics according to the types thereof. For example, glossy paper and similar paper mostly cause specular reflection, while plain paper and similar paper mostly cause diffuse reflection. Therefore, there is a slight difference in the change in the distance coefficient L according to the distance, depending on the characteristic of a recording medium. To further accurately detect the distance between the sensor and the surface of a recording medium, it is desirable to select a distance reference table according to the type of a recording medium, instead of preparing only one distance reference table as described above. In the present exemplary embodiment, the infrared LED 201 and the phototransistors 203 and 204 are disposed so that the angle therebetween forms a specular reflection angle to enable distance detection even for a clear film and a similar recording medium. However, for a recording medium showing difficulty in detecting the distance thereto by specular reflection, it is possible to employ the method of using the visible LED 205, which irradiates light perpendicularly to the recording medium, to measure diffusely reflected light of the visible LED 205.
Next, in step S703, the entire region (overall width) of the recording medium 106 is scanned in the arrow C direction illustrated in
After the detection of the width of the recording medium 106 and the measurement of the height of the recording medium 106 as described above, in step S704, the edge position of the recording medium 106 is detected again by conveying the recording medium 106 by a predetermined amount in the forward direction or in the reverse direction and acquiring the output “a” of the phototransistor 203. If the edge position detected this time is different from the edge position detected at the time of detection of the sheet width, the control unit 500 determines that “the sheet is skewed”, and prompts a user to reset the recording medium 106. After the user resets the recording medium 106 accordingly, the carriage 101 is returned to a predetermined position. Then, in step S705, the cap is closed (the recording head 103 is capped), and the recording apparatus is set into “a standby state”, thereby ending the series of operations.
Next, in step S803, the control unit 500 performs a calculation of “a height change amount” of the recording medium 106.
Next, in step S804, it is determined whether the change amount ΔH within the predetermined range (for each predetermined interval ΔX) exceeds a threshold value. It should be noted that the determination in step S804 does not immediately lead to error processing, and only turns an internal flag on. If the change amount ΔH calculated in step S803 does not exceed the threshold value (NO in step S804), the first process is ended while the internal flag remains off. On the other hand, if it is determined in step S804 that the change amount ΔH calculated in step S803 exceeds the threshold value (YES in step S804), the process proceeds to step S805 in which the internal flag is turned on, and then the first process is ended. In particular, in the state illustrated in
In the above-described first process, the conditions are determined in consideration of “cutting of a sheet”. For example, if the recording apparatus employs a suction-type platen configured to attract the recording medium 106 with use of a negative pressure suction force, the suction amount of the platen 107 is maximized under any ambient environment or for any type of recording medium so as to facilitate cutting of the recording medium. This is because the recording medium may be in different states with respect to sheet uplift due to different conditions during a cutting operation and during a recording operation, and the influence of this difference should be reduced. Another reason is because after the recording medium 106 is cut, the conveyance operation of the recording medium 106 may cause alleviation of a sheet uplift state, and simply easing the threshold value for determining “abnormality” in this case may result in overlooking sheet uplift that should be detected, and such overlooking should be avoided. Therefore, in the present exemplary embodiment, the recording apparatus is configured so that “abnormality” is not determined immediately even when a drastic change is detected in the height data in the first process, and a second process is subsequently performed to detect the distance to the recording medium 106 by selecting detection conditions according to a recording operation. As a result, it is possible to improve the accuracy of detecting an abnormal state.
In other words, the second process is a process for measuring the distance to the recording medium 106 throughout the entire region of the recording medium 106 under the same conditions as a recording operation (without using the cutter unit 109), if the detection unit 102 detects that an amount of change in the distance to the recording medium 106 is equal to or more than the predetermined value in the first process. For example, if the platen 107 is embodied by a suction-type platen configured to attract the recording medium 106 onto the conveyance surface with use of a suction force by, for example, a negative pressure or electrostatic adsorption, this suction force (suction amount) is set according to the type (characteristic) of the recording medium 106 or the ambient environment (temperature and humidity), similarly to the setting during a recording operation. Further, the cutter unit 109 is set into the non-cutting state in which the cutting blade of the cutter unit 109 is retracted as described above so as not to cause a change in the posture of the carriage at the time of the start of a recording operation. In this way, in step S903, while the carriage 101 is moved in the arrow C direction, the control unit 500 acquires the height data throughout the entire region of the recording medium 106 in the width direction, with use of the detection unit 102.
Next, in step S904, it is determined whether the height data acquired in step S903 is equal to or more than a predetermined value. The height of the recording medium 106 is equal to or more than the predetermined value, when the distance from the detection unit 102 to the recording medium 106 is equal to or less than a predetermined distance, or in other words, when the distance between the recording medium 106 and the recording head 103 is equal to or less than a threshold value that may cause damage to the recording head 103. If the height data is equal to or more than the predetermined value (YES in step S904), the process proceeds to step S905 in which it is determined that the recording medium 106 is in an “abnormal” state, where sheet uplift is significant enough to possibly cause damage to the recording head 103. Then, error processing is performed. At this time, since no change occurs in the posture of the carriage 101 due to the operation of the cutter unit 109, whether the state is “abnormal” is determined based on the predetermined value X illustrated in
The ink jet recording apparatus of the above-described exemplary embodiment includes the recording head 103 configured to discharge ink onto the recording medium 106, the carriage 101 carrying the recording head 103 mounted thereon and configured to make a reciprocating motion, and the cutter unit 109 mounted on the carriage 101 and configured to cut the recording medium 106. The ink jet recording apparatus further includes the detection unit 102 mounted on the carriage 101 and configured to detect the distance to the recording medium 106, and the control unit 500 for controlling an operation of the recording apparatus. The ink jet recording apparatus configured in this way determines whether the recording medium 106 is in an abnormal state by performing the following first and second processes. In the first process, the detection unit 102 detects the change amount ΔH of the distance to the recording medium 106 when the cutter unit 109 cuts the recording medium 106. In the second process, the detection unit 102 detects the distance to the recording medium 106 with the cutter unit 109 retracted if the detection unit 102 detects a change amount equal to or more than the predetermined value in the first process. Then, the control unit 500 determines that the recording medium 106 is in an abnormal state if the distance from the recording head 103 to the recording medium 106 that is detected in the second process is equal to or less than the predetermined value, while the control unit 500 determines that the recording medium is not in an abnormal state if the distance from the recording head 103 to the recording medium 106 that is detected in the second process is more than the predetermined value. Then, if the control unit 500 determines that the recording medium 106 is not in an abnormal state, a recording operation is started with use of the recording head 103.
According to the above-described exemplary embodiment, it is possible to avoid unnecessary execution of the operation for determining an abnormal state when obvious sheet uplift does not occur, due to the execution of the first process at the time of cutting the recording medium 106. Further, it is possible to distinguish a phenomenon peculiarly occurring during a cutting operation from a phenomenon occurring during a recording operation, due to the execution of the second process under same conditions as an actual recording operation without immediately determining an abnormality even when a large change is detected in the first process. As a result, it is possible to improve the accuracy of detecting an abnormal state of the recording medium 106. Therefore, it becomes possible to prevent a recording failure that might otherwise be caused due to an abnormal state, by accurately detecting whether a conveyance state of the recording medium 106 is abnormal without reducing throughput of a recording operation, by an easy method.
The second process in the present exemplary embodiment will be described with reference to
Next, in step S1104, the control unit 500 compares the height data acquired in step S1103 with the height data detected at the time of measurement of the sheet width in step S703 of
According to the present exemplary embodiment, it is possible to cancel factors peculiar to the apparatus such as warpage of the guide shaft 105 and unevenness of the surface of the plate 107, by acquiring the data of the distance to the recording medium 106 at the time of measurement of the width of the recording medium 106, and comparing it with the data acquired in the second process. As a result, it is possible to improve the accuracy of detecting an abnormal state of the recording medium 106. Therefore, it becomes possible to more efficiently prevent a recording failure that might otherwise be caused due to an abnormal state, by accurately detecting whether the conveyance state of the recording medium 106 is abnormal without reducing throughput of a recording operation, by an easy method.
A third exemplary embodiment employs, as the platen 107, a suction-type platen capable of attracting the recording medium 106 onto the conveyance surface with use of a suction force by a negative pressure or electrostatic adsorption so that the recording medium 106 does not float from the conveyance surface. In other words, in the present exemplary embodiment, the platen supporting the recording medium 106 at a position opposing the recording head 103 in the first exemplary embodiment is replaced with a platen capable of attracting the recording medium 106 by a suction force. Then, the suction force of the platen in the second process is controlled so as to be changed according to the type (characteristic) of recording medium or an ambient environment (temperature and humidity), as in the setting during a recording operation. For example, if the recording medium 106 has low rigidity, a strong suction force may make the unevenness of the surface of the recording medium 106 noticeable and influence the recorded image quality. Therefore, in this case, a small value is set to the suction force. On the contrary, if the recording medium 106 has high rigidity, a large value is set to the suction force so as to prevent sheet uplift. In addition, since a change in an ambient environment causes a change in the state of the recording medium 106, the suction force is also changed according to an ambient environment, if necessary. The present exemplary embodiment is different from the first exemplary embodiment in terms of the above-described features, but other than that, the present exemplary embodiment is structurally similar to the first exemplary embodiment.
According to the present exemplary embodiment, it is possible to perform the detection operation under a same suction force as the setting during a recording operation in the second process, even when the suction force of the platen 107 during a recording operation is different from the suction force during a cutting operation, whereby the state of sheet uplift is different from each other. As a result, it is possible to improve the accuracy of detecting an abnormal state of the recording medium 106. Therefore, it becomes possible to more efficiently prevent a recording failure that might otherwise be caused due to an abnormal state, by accurately detecting whether the conveyance state of the recording medium 106 is abnormal without reducing throughput of a recording operation, by an easy method.
In a fourth exemplary embodiment, the positional relationship among the detection unit 102, the recording head 103, and the cutter unit 109 mounted on the carriage 101 in the above-described first exemplary embodiment is replaced with the positional relationship in which the detection unit 102 is disposed between the cutter unit 109 and the recording head 103 in the movement direction of the carriage 101. As illustrated in
According to the present exemplary embodiment, it is possible to detect a sheet uplift state generated during a cutting operation before the recording head 103 reaches the sheet uplift state, due to the presence of the detector (detection unit 102) between the cutter (cutting unit 109) and the recording head 103 in the main scanning direction. As a result, it is possible to ensure detection of a sheet uplift state causing the recording head 103 to be scratched. Therefore, it becomes possible to more efficiently prevent a recording failure that might otherwise be caused due to an abnormal state, by accurately detecting whether the conveyance state of the recording medium 106 is abnormal without reducing throughput of a recording operation with use of an easy method.
A fifth exemplary embodiment is configured so that, when the detection unit 102 detects the change amount of the distance to the recording medium 106 while the cutter unit 109 is cutting the recording medium 106, the detection result within a predetermined range from a start of cutting by the cutter unit 109 is not used for the determination whether the recording medium 106 is in an abnormal state. In other words, the present exemplary embodiment is different from the first exemplary embodiment in terms of detection of the change amount of the distance to the recording medium 106 in the first process; the present exemplary embodiment is configured so that, in the first process, the detection result within the predetermined range from a start of cutting is excluded from the determination whether the recording medium 106 is in an abnormal state. The present exemplary embodiment is similar to the first exemplary embodiment, except for the above-described features.
For example, it may be hard to cut a recording medium by the cutter unit 109 depending on the type (characteristic) of the recording medium and the ambient environment. In such a case, the cutter unit 109 may be “caught” and thereby the posture of the carriage 101 may be tilted, when the cutter unit 109 starts cutting after reaching the edge of the recording medium 106 in the width direction. The tilt of the carriage 101 may cause the distance detected by the detection unit 102 to change even when the recording medium 106 is in a normal state, thereby making accurate distance detection impossible. The present exemplary embodiment considers the possibility of such an inconvenient situation, and is configured such that sheet uplift is not determined within the predetermined range from a start of cutting by the cutter unit 109.
The present exemplary embodiment is configured such that the vicinity of the cutting start position is excluded from the detection, since a start of cutting may cause the posture of the carriage 101 and therefore the output of the detection unit 102 to change depending on the characteristic of recording medium. As a result, it is possible to prevent false detection of “abnormality” when the recording medium 106 is actually in a normal state. Therefore, it becomes possible to more efficiently prevent a recording failure that might otherwise be caused due to an abnormal state, by accurately detecting whether the conveyance state of the recording medium 106 is abnormal without reducing throughput of a recording operation, by an easy method.
A sixth exemplary embodiment is configured by adding, to the first exemplary embodiment, a conveyance operation for discharging a recorded portion of the recording medium 106 which is cut by the cutter unit 109 before execution of the second process.
Further, this push-out operation is an operation of discharging the recorded portion, which is cut off, by the conveyance roller. At this time, the carriage 101 is retracted to the vicinity of the cap which is outside the recording region. Then, in step S1502, the control unit 500 checks the state of the internal flag, in similar manner to step S901 of
Next, in step S1505, the control unit 500 determines whether the height data acquired in step S1504 is equal to or more than a predetermined value. If the height data is equal to or more than the predetermined value (YES in step S1505), the process proceeds to step S1506 in which the control unit 500 determines that the recording medium 106 is in a “sheet jam” state which is sheet uplift significant enough to cause damage to the recording head 103, and the error processing is performed. On the other hand, if the height data is less than the predetermined value (NO in step S1505), the control unit 500 determines that the recording medium 106 is in a normal state, and then starts a recoding operation. The present exemplary embodiment is different from the first exemplary embodiment in terms of the above-described features, but other than that, the present exemplary embodiment is structurally similar to the first exemplary embodiment.
According to the present exemplary embodiment, it is possible to perform an operation for detecting a state of the recording medium 106 equalized by a conveyance operation, by the detection operation after the operation for discharging the recorded portion, which is cut off, of the recording medium 106. As a result, it is possible to prevent false detection of “abnormality” when the sheet uplift state is resolved and a normal state is established after the first process. Therefore, it becomes possible to more efficiently prevent a recording failure that might otherwise be caused due to an abnormal state, by accurately detecting whether the conveyance state of the recording medium 106 is abnormal without reducing throughput of a recording operation with use of an easy method.
In the above-described exemplary embodiments, abnormal sheet uplift is determined by performing the first and second processes. However, the recording apparatus may simply have different values as a threshold value for determining an abnormality in the height of the recording medium 106 during a cutting operation using the cutter unit 109 and a threshold value for determining an abnormality in the height of the recording medium 106 during a non-cutting operation. In this case, when the recording medium 106 is scanned without being cut, an abnormality is determined if the measurement result indicates that the distance from the recording head 103 to the recording medium 106 is equal to or smaller than a first threshold value so as to cause damage to the recording medium 103. When the recording medium 106 is being cut by the cutter unit 109, an abnormality is determined if the measurement result indicates that the distance from the recording head 103 to the recording medium 106 is equal to or smaller than a second threshold value that is smaller than the first threshold value. The second threshold value is set in consideration of the change in the posture of the carriage 101 that might be caused during a cutting operation.
The above-described exemplary embodiments can also be applied in a similar manner regardless of the number of recording heads, the type and shape of ink used, and can also be applied in a similar manner for recording media made of various different materials such as paper, a plastic film, printing paper, and an unwoven fabric.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all modifications, equivalent structures, and functions.
This application claims priority from Japanese Patent Application No. 2010-039728 filed Feb. 25, 2010, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2010-039728 | Feb 2010 | JP | national |
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| Number | Date | Country | |
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| 20110205279 A1 | Aug 2011 | US |
