Patent Publication Number: US-10328723-B2

Title: Recording apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application is continuation of U.S. patent application Ser. No. 15/436,546, filed Feb. 17, 2017, which is a continuation of U.S. patent application Ser. No. 15/016,687, filed Feb. 5, 2016, which is a continuation of U.S. patent application Ser. No. 14/672,853, filed Mar. 30, 2015, and further claims priority from Japanese Patent Application No. 2014-072720, filed on Mar. 31, 2014, the disclosures of all of which are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND 
     Field of the Invention 
     The present invention relates to a recording apparatus which records an image on a recording medium. 
     Description of the Related Art 
     In Japanese Patent No. 4062428, an ink-jet recording apparatus, which detects a width of a recording paper for each recording paper at the time of recording an image on the recording paper, has been described. In the ink-jet recording apparatus described, at the time of carrying out a first main scanning operation of a recording head, two end portions of the recording paper are detected by a sensor, and the width of the recording paper is acquired. Since the width of the recording paper is acquired for each recording paper, it is possible to maintain an image quality. 
     SUMMARY 
     However, in the ink-jet recording apparatus described in Japanese Patent No. 4062428, for acquiring the width of the recording paper for each recording paper, it is necessary to move the sensor to positions at which the sensor can detect both ends of the recording paper respectively, for each recording paper. For instance, when recording jobs for recording images on one or more than one recording papers are received one by one and when an image according to each recording job is recorded on one of the recording papers, the width of each recording paper is acquired for each recording paper. This leads to a problem that a time from receipt of the recording job to discharge of the recording paper having an image recorded thereon becomes long, for each recording job. 
     Therefore, an object of the present teaching is to provide a recording apparatus which is capable of shortening the time from receipt of a recording job to discharge of a recording medium having an image according to the recording job recorded thereon. 
     According to a first aspect of the present teaching, there is provided a recording apparatus including: a container configured to contain a recording medium; a conveying mechanism configured to convey the recording medium contained in the container along a conveying path; a recording head configured to record an image on the recording medium that has been conveyed in a first direction through the conveying path by the conveying mechanism; a moving mechanism including a carriage that supports the recording head and configured to move the carriage reciprocatingly together with the recording head in a second direction which intersects the first direction; a first sensor installed in the carriage on an upstream side of the recording head in the first direction and configured to detect the recording medium; a second sensor configured to detect a change of a state of the container; a storage unit configured to store width information relating to the second direction of the recording medium that is conveyed by the conveying mechanism; and a controller configured to control the conveying mechanism, the moving mechanism, and the recording head to record an image on at least one recording medium based on width information and a recording job which is a series of processing corresponding to a recording command, and configured to judge whether a predetermined condition for updating the width information is satisfied, the predetermined condition being detection of the change in the state of the container by the second sensor; wherein after the controller judged that the predetermined condition has been satisfied, and before an image is recorded on a first recording medium based on the recording job, the controller is configured to: acquire width information of the first recording medium by detecting two ends in the second direction of the first recording medium by the first sensor; and store the width information of the first recording medium, which has been acquired, in the storage unit until the controller judges next time that the predetermined condition has been satisfied. 
     According to a second aspect of the present teaching, there is provided a recording apparatus including: a container configured to contain a recording medium; a conveying mechanism configured to convey the recording medium contained in the container along a conveying path; a recording head configured to record an image on the recording medium that has been conveyed in a first direction through the conveying path by the conveying mechanism; a moving mechanism including a carriage that supports the recording head and configured to move the carriage reciprocatingly together with the recording head in a second direction which intersects the first direction; a first sensor installed in the carriage on an upstream side of the recording head in the first direction and configured to detect the recording medium; a jam sensor provided for the conveying path and configured to detect jamming of the recording medium in the conveying path; a storage unit configured to store width information relating to the second direction of the recording medium that is conveyed by the conveying mechanism; and a controller configured to control the conveying mechanism, the moving mechanism, and the recording head to record an image on at least one recording medium based on width information and a recording job which is a series of processing corresponding to a recording command, and configured to judge whether a predetermined condition for updating the width information is satisfied, the predetermined condition being detection of the jamming of the recording medium in the conveying path by the jam sensor; wherein after the controller judged that the predetermined condition has been satisfied, and before an image is recorded on a first recording medium based on the recording job, the controller is configured to: acquire width information of the first recording medium by detecting two ends in the second direction of the first recording medium by the first sensor; and store the width information of the first recording medium, which has been acquired, in the storage unit until the controller judges next time that the predetermined condition has been satisfied. 
     Accordingly, even at the time of recording images on the plurality of recording media based on the plurality of recording jobs, the width information of the first recording medium is maintained in the storage unit and not updated until the second sensor detects a change in the state of the container next time or until the jam sensor detects the jamming of the recording medium in the conveying path next time. Therefore, an image is recorded on the recording medium based on the width information maintained in the storage unit until the second sensor detects the change in the state of the container or until the jam sensor detects the jamming of the recording medium in the conveying path next time. Accordingly, it is not necessary to update the width information for each recording job, and with respect to a recording job for which updating of the width information is not required, it is possible to shorten the time period from receiving the recording job to discharging the recording medium on which the image has been recorded. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a multi-function peripheral. 
         FIG. 2  is a schematic side view showing an internal structure of a printer unit shown in  FIG. 1 . 
         FIG. 3  is a plan view of main components of the printer unit shown in  FIG. 1 . 
         FIG. 4  is a bottom view of a carriage and a recording head shown in  FIG. 2 . 
         FIG. 5  is a partial cross-sectional view of a width detection sensor shown in  FIG. 4 . 
         FIG. 6  is a block diagram showing an electrical configuration of the printer unit. 
         FIGS. 7A to 7C  show a flowchart showing a procedure of an image recording operation of the printer unit. 
         FIG. 8  is an explanatory diagram showing positions at which the width detection sensor is positioned at the time of detecting positions of end-portions. 
         FIG. 9A  and  FIG. 9B  are explanatory diagrams showing positions at which the width detection sensor is positioned at the time of recording an image within an end-portion area of the paper. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     A multi-function peripheral  10  in which a printer unit according an embodiment of the present teaching is adopted will be described below. The multi-function peripheral  10  is used while being placed in a state shown in  FIG. 1 . In the present embodiment, three directions indicated by arrow marks in  FIG. 1  are an up-down direction  7 , a front-rear direction  8 , and a left-right direction  9 . The three directions indicated in  FIG. 1  are similar in the other diagrams as well. 
     &lt;Outline of Multi-function Peripheral&gt; 
     As shown in  FIG. 1 , the multi-function peripheral  10  is formed to be substantially thin rectangular parallelepiped. A printer unit  11  which is an example of a recording apparatus of the present teaching is provided at a lower portion of the multi-function peripheral  10 . The multi-function peripheral  10  has various functions such as a facsimile function and a print function. 
     The printer unit  11  includes a casing  14  which covers the periphery. A front wall  17  is arranged on a front side of the casing  14 , and is spread in the up-down direction  7  and the left-right direction  9  respectively. An opening  13  is formed at a substantially central portion of the front wall  17 . The printer unit  11  is provided with a paper feeding tray  15  and a paper discharge tray  16  at a lower stage and an upper stage respectively, to be exposed partially from the opening  13 . The paper feeding tray  15  can be inserted into and drawn out through the opening  13  in the front-rear direction  8 , or is arranged to be detachable from the casing  14 . The paper feeding tray  15  in the present embodiment is capable of containing papers P of various sizes from A4 and smaller than A4. A paper P contained in the paper feeding tray  15  is conveyed to an interior of the printer unit  11 , and a desired image is printed thereon, and the paper P is discharged to the paper discharge tray  16 . 
     The multi-function peripheral  10  is connected to an external equipment such as a personal computer (hereinafter referred to as a PC) mainly. The multi-function peripheral  10  records an image (including a text) on the paper P based on a recording job (data which indicates a series of processing corresponding to a recording command for recording an image on one or more than one paper P) transferred from the PC and including image data. 
     &lt;Internal Structure of Printer Unit&gt; 
     Next, an internal structure of the printer unit  11  will be described below. As shown in  FIG. 2 , the printer unit  11  includes a feeding unit  30 , a pair of conveying rollers  55 , a recording unit  20 , a pair of discharge rollers  56 , an attachment/detachment sensor  18  (an example of the second sensor), a first paper sensor  19   a , a second paper sensor  19   b , a width detection sensor  50  (an example of the first sensor, refer to  FIG. 4 ), and a control unit  5  (an example of the controller, refer to  FIG. 6 ), and the casing  14  contains these components. The first paper sensor  19   a  and the second paper sensor  19   b  are examples of the jam sensor. The feeding unit  30  feeds paper P contained in the paper feeding tray  15  to a conveying path  27 . The pair of conveying rollers  55  conveys the paper P fed by the feeding unit  30 , to the recording unit  20 . The recording unit  20  has an arrangement of, for example, an ink-jet recording type, and records an image on the paper P conveyed by the pair of conveying rollers  55 . The pair of discharge rollers  56  discharges the paper P having the image recorded thereon by the recording unit  20 , to the paper discharge tray  16 . 
     &lt;Feeding Unit&gt; 
     As shown in  FIG. 2 , the feeding unit  30  is provided at an upper side of the paper feeding tray  15 . The feeding unit  30  includes a paper feeding roller  31 , a paper feeding arm  34 , and a gear train  35 . The paper feeding roller  31  is rotatably supported by an end portion of the paper feeding arm  34 . The paper feeding arm  34  is pivotally attached to a frame (not shown in the diagram) of the printer unit  11 . Accordingly, the paper feeding roller  31  is arranged to be movable upward and downward with respect to the paper feeding tray  15 . The gear train  35  includes a plurality of gears arranged in a row inside the paper feeding arm  34 . In this arrangement, as a drive motor  30 M (refer to  FIG. 6 ) is driven, the driving force is transmitted to the gear train  35 , and the paper feeding roller  31  is rotated in a clockwise direction in  FIG. 2 . The paper feeding roller  31  rotates in a state of being in a pressed contact with the paper P on the paper feeding tray  15 . Due to the rotation of the paper feeding roller  31 , the stacked papers P are conveyed to the conveying path  27 . 
     &lt;Paper Feeding Tray&gt; 
     As shown in  FIG. 2 , the paper feeding tray  15  includes an inclined wall portion  12 . The inclined wall portion  12  guides a paper P to the conveying path  27  when the paper P placed in the paper feeding tray  15  is fed by the paper feeding roller  31 . Moreover, the paper feeding tray  15  is provided with a guiding mechanism (not shown in the diagram) which aligns a center of the contained paper P with a center of the conveying path  27  in the left-right direction  9  by an operation of a user. Accordingly, it is possible to feed the paper P to the conveying path  27  in a state that the center of the paper P is aligned as far as possible with the center of the conveying path  27  in the left-right direction  9 . The guiding mechanism may align the paper P such that one end of the paper P is along one end of the conveying path  27 , in the left-right direction  9 . 
     &lt;Attachment/Detachment Sensor&gt; 
     The attachment/detachment sensor  18  is arranged at a position which is at a lower portion on a rear side of the casing  14 , and facing the inclined wall portion  12  of the paper feeding tray  15 , in the front-rear direction  8 . The attachment/detachment sensor  18  is a so-called push-button switch, and has a protrusion  18   a  which is movable in the front-rear direction and which is biased frontward. When the paper feeding tray  15  is attached to the casing  14 , the protrusion  18   a  is pressed by the paper feeding tray  15  as shown in  FIG. 2 . At this time, the attachment/detachment sensor  18  outputs a detection signal, to the control unit  5 , indicating that the paper feeding tray  15  has been attached to the casing  14 . Whereas, when the paper feeding tray  15  is detached from the casing  14 , the protrusion  18   a  is not pressed by the paper feeding tray  15 , and the protrusion  18   a  has a state of protruding further frontward as compared with the state shown in  FIG. 2 . At this time, the attachment/detachment sensor  18  outputs a detection signal, to the control unit  5 , indicating that the paper feeding tray  15  has not been attached to the casing  14 . Accordingly, the control unit  5  is capable of detecting attachment and detachment of the paper feeding tray  15 . The attachment/detachment sensor  18  may be a sensor of a type other than the push-button switch type, and may be any sensor such as an optical sensor, provided that it is capable of outputting a signal indicating a change of an attachment state of the paper feeding tray  15 . 
     &lt;Conveying Path&gt; 
     As shown in  FIG. 2 , the conveying path  27  is bent upward and frontward of the printer unit  11  from an end portion on a rear side of the paper feeding tray  15 , and is extended toward a front-surface side from a rear-surface side (rear side) of the printer unit  11 . Furthermore, the conveying path  27  is lead to the paper discharge tray  16  passing through a pinching position of the pair of conveying rollers  55 , a lower side of the recording unit  20 , and a pinching position of the pair of discharge rollers  56 . The paper P fed from the paper feeding tray  15  is guided to make a U-turn from a lower portion to an upper portion of the casing  14 , and reaches the recording unit  20 . After an image recording is carried out on the recording paper P by the recording unit  20 , the paper P having an image recorded thereon is discharged to the paper discharge tray  16 . The conveying path  27  is defined between an outer-side guide member  29  and an inner-side guide member  28  mutually facing with a predetermined spacing distance intervening therebetween, except for locations where components such as the recording unit  20  are arranged. Moreover, a location of the conveying path  27  where the recording unit  20  is installed is arranged between a recording head  21  which will be described later and a platen  22  (mainly an area on the platen  22 ), and an image is recorded on the paper P when the paper P passes over this portion of the conveying path  27 . 
     &lt;Pair of Conveying Rollers and Pair of Discharge Rollers&gt; 
     The description will be made below letting a direction in which the paper P is conveyed along the conveying path  27  (a direction indicated by an alternate long and two short dashes line in  FIG. 2 ) to be a conveying direction A. As shown in  FIG. 2 , the pair of conveying roller  55  is provided at an upstream side of the recording unit  20  in the conveying direction A. The pair of conveying rollers  55  includes a conveying roller  55   a  which is arranged at a lower side of the conveying path  27  and a pinch roller  55   b  which is arranged at an upper side of the conveying path  27 . The pinch roller  55   b  rotates along with the conveying roller  55   a . The conveying roller  55   a  and the pinch roller  55   b  together pinch the paper P in the up-down direction  7 , and convey the paper P in the conveying direction A. The conveying roller  55   a  may be provided at an upper side of the pinch roller  55   b.    
     The pair of discharge rollers  56  is provided at a downstream side of the recording unit  20  in the conveying direction A. The pair of discharge rollers  56  includes a discharge roller  56   a  which is arranged at a lower side of the conveying path  27 , and a spur roller  56   b  which is arranged at an upper side of the conveying path  27 . The spur roller  56   b  rotates along with the paper discharge roller  56   a . The discharge roller  56   a  and the spur roller  56   b  together pinch the paper P in the up-down direction  7 , and convey the paper P in the conveying direction A. The paper discharge tray  16  is arranged at a downstream side of the pair of discharge rollers  56  in the conveying direction A. The paper discharge tray  16  is provided at a downstream side of the recording unit  20  in the conveying direction A. 
     As the drive motor  30 M is driven, the driving force of the drive motor  30 M is transmitted by a transmission mechanism which is not shown in the diagram to the conveying roller  55   a  and the discharge roller  56   a  in the pair of conveying rollers  55  and the pair of discharge rollers  56  respectively, and the conveying roller  55   a  and the paper discharge roller  56   a  rotate in a clockwise direction in  FIG. 2 . At this time, the conveying roller  55   a  and the discharge roller  56   a  are driven intermittently with a predetermined linefeed width. The rotation of the conveying roller  55   a  and the rotation of the discharge roller  56   a  are synchronized, and the rotation of the conveying roller  55   a  and the rotation of the discharge roller  56   a  are controlled by being detected by a rotary encoder  57  (refer to  FIG. 6 ) provided for the conveying roller  55   a . Thus, the paper P pinched between the pair of conveying rollers  55  is conveyed intermittently on the platen  22  at a predetermined linefeed width. The recording head  21  is scanned for each line feeding, and image recording is carried out from a front-end side of the paper P. The front-end side of the paper P subjected to image recording is, thereafter, pinched between the pair of discharge rollers  56 . Consequently, the paper P is conveyed intermittently at the predetermined line feed width in a state that the front-end side of the paper P is pinched between the pair of discharge rollers  56  and a rear-end side thereof is pinched between the pair of conveying rollers  55 , and image recording is carried out on the paper P by the recording head  21  in a similar manner. As the paper P is conveyed further, the rear end of the paper P passes through the pair of conveying rollers  55 , and is released from the state of being pinched between the pair of conveying rollers  55 . Consequently, the paper P is conveyed intermittently with the predetermined linefeed width upon being pinched between the pair of discharge rollers  56 , and the image recording is carried out on the paper P by the recording head  21  in a similar manner. After the image recording has been carried out on a predetermined area of the paper P, the discharge roller  56   a  is driven to be rotated continuously. Accordingly, the paper P pinched between the pair of discharge rollers  56  is discharged to the paper discharge tray  16 . In such manner, the conveying mechanism of the present teaching, which conveys the paper P, is formed by the feeding unit  30 , the pair of conveying rollers  55 , and the pair of discharge rollers  56 . 
     &lt;First Paper Sensor&gt; 
     The first paper sensor  19   a  is arranged near and upstream side of the pair of conveying rollers  55  in the conveying direction A. The first paper sensor  19   a  includes a light emitting portion  19   a   1  which is arranged at an upper side of the conveying path  27 , and a light receiving portion  19   a   2  which is arranged at a lower side of the conveying path  27 . The light emitting portion  19   a   1  includes a light emitting diode. The light receiving portion  19   a   2  includes an optical sensor. The light emitting portion  19   a   1  and the light receiving portion  19   a   2  are arranged at a center of the conveying path  27  in a direction (the left-right direction  9 ) orthogonal to the conveying direction A. Moreover, the light emitting portion  19   a   1  and the light receiving portion  19   a   2  are arranged to face mutually, and the light receiving portion  19   a   2  is arranged to receive light from the light emitting portion  19   a   1 . The first paper sensor  19   a  detects a front end of the paper P when the light from the light emitting portion  19   a   1  to the light receiving portion  19   a   2  is blocked by the paper P during the conveyance of the paper P, and outputs a detection signal of the paper P to the control unit  5 . Accordingly, the control unit  5  is capable of detecting a position of the front end of the paper P. 
     &lt;Second Paper Sensor&gt; 
     The second paper sensor  19   b  is arranged near the pair of discharge rollers  56  and between the recording unit  20  and the pair of discharge rollers  56 . The second paper sensor  19   b  includes a light emitting portion  19   b   1  which is arranged at an upper side of the conveying path  27 , and a light receiving portion  19   b   2  which is arranged at a lower side of the conveying path  27 . The light emitting portion  19   b   1  includes a light emitting diode. The light receiving portion  19   b   2  includes an optical sensor. The light emitting portion  19   b   1  and the light receiving portion  19   b   2  are arranged at the center of the conveying path  27  with respect to the direction (the left-right direction  9 ) orthogonal to the conveying direction A. Moreover, the light emitting portion  19   b   1  and the light receiving portion  19   b   2  are arranged to face mutually, and the light receiving portion  19   b   2  is arranged to receive light from the light emitting portion  19   b   1 . The second paper sensor  19   b  detects the front end of the paper P when the light from the light emitting portion  19   b   1  to the light receiving portion  19   b   2  is blocked by the paper P during the conveyance of the paper P, and outputs a detection signal of the paper P to the control unit  5 . Accordingly, the control unit  5  is capable of detecting the paper P, and is capable of making a judgment of whether or not a jamming of the paper P has occurred in a portion of the conveying path  27  between the first paper sensor  19   a  and the second paper sensor  19   b.    
     &lt;Recording Unit&gt; 
     As shown in  FIG. 2  and  FIG. 3 , the recording unit  20  includes the recording head  21 , a moving mechanism  40 , and the platen  22 . The moving mechanism  40  includes a carriage  23 . The carriage  23  reciprocates in a scanning direction (which is the left-right direction  9 , and is orthogonal to the conveying direction A). The carriage  23 , as shown in  FIG. 2 , supports the recording head  21  at a lower side of the carriage  23 . A bottom surface of the recording head  21  is a jetting surface  21   a  in which a plurality of nozzles  21   b  (refer to  FIG. 4 ) is formed. Each of the plurality of nozzles  21   b  jets an ink onto the recording paper P conveyed beneath the recording head  21 . The platen  22  is arranged below the jetting surface  21   a , and supports the paper P which is conveyed by the pair of conveying rollers  55 . 
     As shown in  FIG. 3 , inks of magenta (M), cyan (C), yellow (Y), and black (Bk) colors are supplied from ink tanks which are not shown in the diagram to the recording head  21  through ink tubes  33 . The recording head  21  jets the inks of various colors as fine ink droplets through the nozzles  21   b  by a control of the control unit  5  based on a recording job. In other words, an image is recorded on the paper P that is conveyed on the platen  22 , when the recording head  21  is scanned with respect to the paper P due to the reciprocation of the carriage  23  in the left-right direction  9  and the ink droplets of various colors are jetted through the nozzles  21   b.    
     As shown in  FIG. 3 , the moving mechanism  40  includes a pair of guide rails  24  and a belt transmission mechanism  37 . Guide rails in the pair of guide rails  24  are arranged to be isolated in the front-rear direction  8 . The pair of guide rails  24  extends in the left-right direction  9  to be parallel. The carriage  23  is arranged to span the pair of guide rails  24 , and reciprocates along the left-right direction on the pair of guide rails  24 . 
     The belt transmission mechanism  37  is arranged on an upper surface of the guide rail  24  on a front side. The belt transmission mechanism  37  includes two pulleys  38  and  39 , and a timing belt  36 . The pulley  38  is provided for a right-end portion of the guide rail  24  on the front side, and the pulley  39  is provided for a left-end portion of the guide rail  24  on the front side. The timing belt  36  is an endless belt put around the pulleys  38  and  39 . A driving force from the carriage drive motor  40 M (refer to  FIG. 6 ) is inputted to the pulley  38 . In this mechanism, as the carriage drive motor  40 M is driven, the pulley  38  rotates, and the timing belt  36  is turned around. The timing belt  36  is fastened to the carriage  23 . Consequently, the reciprocating of the carriage  23  is realized by turning around of the timing belt  36 . 
     A linear encoder  35  in the form of a strip is installed along the left-right direction  9  on the guide rail  24  on the front side. In the linear encoder  35 , detection is made by a photo interrupter (a component of the linear encoder  35 ), and the reciprocating of the carriage  23  is controlled according to an encoder amount. 
     The platen  22  is arranged to spread over a central portion, within a reciprocation area of the carriage  23 , on which the paper P passes. A width of the platen  22  in the left-right direction  9  is sufficiently larger than the maximum width of the paper P that can be conveyed (width of A4 size in the present embodiment), and the two ends of the paper P in the left-right direction  9  surely pass over the platen  22 . Moreover, for a color of an upper surface of the platen  22  which carries the paper P, a color having a reflectivity different from a reflectivity of white color (which is the color of the paper P in general) is suitable, and a color which is particularly preferable is black color. 
     Moreover, as shown in  FIG. 3 , a maintenance mechanism  60  is arranged on a right side of the platen  22  in the left-right direction  9 , and a waste-ink tray  42  is arranged on a left side of the platen  22 . In other words, the maintenance mechanism  60  and the waste-ink tray  42  are arranged outside of the conveying path  27  through which the paper P is conveyed. The maintenance mechanism  60  is a mechanism for preventing drying of the jetting surface  21   a  and for eliminating air bubbles and foreign particles together with the ink from the nozzles  21   b  by suction. The maintenance mechanism  60  includes a cap which covers the jetting surface  21   a  of the recording head  21 , a pump mechanism (not shown in the diagram) which is to be connected to the recording head  21  via the cap  61 , and a moving mechanism (not shown in the diagram) for bringing the cap in contact with or separating the cap from the jetting surface  21   a  of the recording head  21 . At the time of eliminating air bubbles etc. in the recording head  21 , the carriage  23  is moved such that the recording head  21  is positioned above the cap  61 . In this state, the cap  61  is moved upward and is brought in a close contact such that the cap  61  seals the nozzles  21   b  of the jetting surface  21   a  of the recording head  21 , and the ink is sucked from the nozzles  21   b  of the recording head  21  by the pump mechanism which is connected to the cap  61 . 
     The waste-ink tray  42  is a tray for receiving the ink that is jetted preliminarily from the recording head  21 . Moreover, the preliminary jetting is called as flushing. By carrying out flushing of the recording head  21 , the drying of the ink inside the nozzles  21   b  is suppressed. Moreover, a felt is laid in the waste-ink tray  42 . When the recording head  21  carries out flushing, the ink that has been jetted preliminarily is absorbed by the felt. 
     &lt;Width Detection Sensor&gt; 
     As shown in  FIG. 4 , the width detection sensor  50  is mounted on the carriage  23  along with the recording head  21 . As shown in  FIG. 4  and  FIG. 5 , the width detection sensor  50  includes a light emitting portion  51  which includes a light emitting diode, and a light receiving portion  52  which includes an optical sensor. As shown in  FIG. 5 , the width detection sensor  50  is configured such that the light emitting portion  51  irradiates light toward the platen  22 , and the light receiving portion  52  receives the light reflected. 
     The color of the upper surface of the platen  22  is a color having the reflectivity different from the reflectivity of paper P, such as black color. In a case that there is no recording paper P on the platen  22 , since the light receiving portion  52  receives light reflected from the platen  22  having a low reflectivity, detected value (AD value) by the width detection sensor  50  becomes low. Whereas, in a case that there is a paper P on the platen  22 , since the light receiving portion  52  receives light reflected from the paper P having a high reflectivity, the detected value (AD value) by the width detection sensor  50  becomes high. Consequently, it is possible to detect the presence or absence of the paper P by a difference in an amount of reflected light which is received by the width detection sensor  50 . 
     As shown in  FIG. 4 , the width detection sensor  50  is mounted on the carriage  23  at an upstream side of the recording head  21  in the conveying direction A (in other words, between the recording head  21  and the pair of conveying rollers  55 ), and is configured to reciprocate in the scanning direction by the carriage  23 . Accordingly, it is possible to detect position information of the left-end portion and the right-end portion of the paper P, and it is possible to acquire width information of the paper P that is conveyed. As shown in  FIG. 4 , in the ink jetting surface  21   a  of the recording head  21 , the plurality of nozzles  21   b  are aligned in the conveying direction A of the paper P for each color ink of magenta, cyan, yellow, and black. The number of nozzles  21   b  and a pitch of adjacent nozzles  21   b  in the conveying direction A may be set appropriately upon taking into consideration factors such as resolution. Moreover, the number of rows of the nozzles  21   b  may be increased or decreased according to the number of colors of ink. 
     &lt;Control Unit&gt; 
     As shown in  FIG. 6 , the control unit  5  includes a CPU (central processing unit)  101 , a ROM (read only memory)  102 , a RAM (random access memory)  103 , and an ASIC (application specific integrated circuit)  104 , and these components cooperate to control operation of the carriage drive motor  40 , the recording head  21 , the drive motor  30 M, and the like. For example, the control unit  5  controls the drive motor  30 M, the carriage drive motor  40 M, the recording head  21 , and the like, based on a recording job that has been transmitted from an external apparatus such as a PC, to record an image etc. on the paper P. Data (such as image data, and information of paper P on which the image is to be recorded), which is necessary at the time of executing a computer program, is stored temporarily in the RAM  103 . In other words, the RAM  103  corresponds to a storage unit of the present teaching. Moreover, as shown in  FIG. 6 , the attachment/detachment sensor  18 , the width detection sensor  50 , the first paper sensor  19   a , the second paper sensor  19   b , the linear encoder  35 , the rotary encoder  57 , and a power supply switch  99  are connected to the control unit  5 . 
     Moreover, in  FIG. 6 , one CPU  101  and one ASIC  104  are shown. However, the control unit  5  may include only one CPU  101 , and this only one CPU  101  may carry out the necessary processing collectively, or the control unit  5  may include a plurality of CPUs  101 , and the plurality of CPUs  101  may carry out the necessary processing by sharing. Moreover, the control unit  5  may include only one ASIC  104 , and this only one ASIC  104  may carry out the necessary processing collectively, or the control unit  5  may include a plurality of ASICs  104 , and the plurality of ASICs may carry out the necessary processing by sharing. 
     Next, an image recording operation in the printer unit  11  will be described below while referring to  FIGS. 7A to 7C ,  FIG. 8 ,  FIG. 9A , and  FIG. 9B . In a case of recording an image on the paper P by the printer unit  11 , firstly, as shown in  FIG. 7A , the power supply switch  99  is pushed and the multi-function peripheral  10  is switched ON (power supply ON: step S 1 ). At this time, the control unit  5  makes a judgment that a first predetermined condition (in other words, the multi-function peripheral  10  is switched ON) has been satisfied, and initializes the width information of the paper P and the position information of the end portions of the paper P stored in the RAM  103 . As the initialization is carried out in such manner, at the time of carrying out image recording on the paper P by switching the multi-function peripheral  10  ON, it is possible to prevent the width information and the position information of the end portions, that have been stored before the multi-function peripheral  10  is switched ON, from being used. Moreover, even in a case that the paper P has been changed to a paper of different size while the multi-function peripheral  10  is switched OFF, it is possible to prevent the width information and the position information of the end portions before the initialization from being used accidentally. 
     Next, the control unit  5 , based on the detection signal from the attachment/detachment sensor  18 , judges whether or not the paper feeding tray  15  has been detached from and attached to the casing  14  (step S 2 ). At step S 2 , as the detection signal indicating detachment and attachment of the paper feeding tray  15  is outputted from the attachment/detachment sensor  18  (in other words, as a detection signal indicating that the paper feeding tray  15  has been detached is outputted, and then the detection signal indicating that the paper feeding tray  15  has been attached is outputted), the control unit  5  judges that a second predetermined condition has been satisfied. In other words, the control unit  5  judges that the paper feeding tray  15  has been detached and attached by the user, and the process advances to step S 3 . Whereas, in a case that the detection signal is not outputted from the attachment/detachment sensor  18 , the control unit  5  judges that the paper feeding tray  15  has neither been detached nor attached by the user, and the process advances to step S 4 . The second predetermined condition is a condition related to a size change of the paper P. This is because the user sometimes replaces the paper P in order to change the size of the paper to a different size, when the user detaches and attaches the paper feeding tray  15 . At step S 3 , the control unit  5  initializes the width information and the position information of the end portions of the paper P stored in the ROM  103 , similarly as at step S 1 . 
     At step S 4 , in a case that no recording job is received (NO at step S 4 ), steps S 2  and S 3  are carried out repeatedly. Moreover, as the control unit  5  receives a recording job from the PC (YES at step S 4 ), the process advances to step S 5 . At step S 5 , the control unit  5  controls the drive motor  30 M and a paper P is fed from the paper feeding tray  15  by the paper feeding roller  31  up to a position where a front end of the paper P is detected by the first paper sensor  19   a . Thereafter, at step S 6 , the control unit  5  judges whether or not the width information of the paper P which is being conveyed has been stored in the RAM  103 . In a case that the width information of the paper P has not been stored in the RAM  103  (NO at step S 6 ), the process advances to step S 7 , and in a case that the width information of the paper P has been stored in the RAM  103  (YES at step S 6 ), the process advances to step S 8 . The width information of the paper P is information, of the width of the paper P being conveyed actually, that has been acquired at step S 7  or step S 19  to be described later, and that differs from information of paper (information of size of the paper P) included in the recording job. 
     At step S 7 , the control unit  5  executes acquiring processing of the width information of the paper P which is being conveyed. In other words, the control unit  5  controls the drive motor  30 M, and conveys the paper P by the paper feeding roller  31  and the conveying roller pair  55  up to a position at which the front end of the paper P faces the width detection censor  50 . At this time, an amount of rotation, that has been inputted to the conveying roller  55   a  after the first paper sensor  19   a  detected the paper P, is obtained as an encoder amount of the rotary encoder  57 , and the paper P is conveyed such that the front end of the paper P is directly below the width detection sensor  50 . As the front end of the paper P is pinched by the pair of conveying rollers  55  and the paper P is ready to be conveyed, the paper feeding roller  31  is separated from the paper P by the paper feeding arm  34 , and conveying of the paper P by the paper feeding roller  31  is stopped. After this, the control unit  5  controls the carriage drive motor  40 M and moves the width detection sensor  50  from a first position to a second position. In other words, as shown in  FIG. 8 , the control unit  5  controls the carriage drive motor  40 M such that the width detection sensor  50  is arranged at a position on a right side of a right-end portion of the paper P (in other words, the second position indicated by alternate long and two short dashes line in  FIG. 8 ) after arranging the width detection sensor  50  on a left side of a left-end portion of the paper P (in other words, the first position indicated by solid lines in  FIG. 8 ). At this time, the control unit  5 , firstly, arranges the width detection sensor  50  at the first position, based on the size of the paper P indicated by the paper information included in the recording job. Thereafter, the control unit  5  moves the width detection sensor  50  to the second position, based on the size of the paper P indicated by the paper information. A starting point (an origin) of the encoder amount in the linear encoder  35  has been set in advance. Concretely, as shown in  FIG. 8 , the carriage  23  is moved to a position on the extreme left side (a third position on the left side of the first position indicated by alternate long and two short dashes lines in  FIG. 8 ) in a range of movement of the carriage  23 , and by resetting the encoder amount to zero at this time, the starting point of the encoder amount of the linear encoder  35  is set. Moreover, at the time of moving the width detection sensor  50  from the first position to the second position, the width detection sensor  50  irradiates predetermined amount of light from the light emitting portion  51 , and receives reflected light by the light receiving portion  52 . Moreover, the AD value which is an output value of the light receiving portion  52  is stored temporarily in the RAM  103  upon being associated with the encoder amount, of the linear encoder  35 , which can be position information of the carriage  23 . 
     Detection of the end portion of the paper P is carried out in real time with respect to the AD value that is outputted sequentially from the width detection sensor  50  associated with the movement of the carriage  23 . More elaborately, the AD value outputted by the width detection sensor  50  is stored temporarily in the RAM  103 , and the control unit  5  detects the end portion of the paper P based on a change in an output level of the AD value. Moreover, once the left end of the paper P has been detected, the control unit  5  stores a position of the left end as position information of the left-end portion (the encoder amount of the linear encoder  35 ) in the RAM  103 , and once the right end of the paper P has been detected, the control unit  5  stores a position of the right end as position information of the right-end portion (the encoder amount of the linear encoder  35 ) in the RAM  103 . Based on the position information of the left-end portion and the position information of the right-end portion at this time, the control unit  5  acquires width information of the paper P (information of the width of the paper P that is conveyed practically), and stores the width information in the RAM  103 . In other words, by subtracting an encoder amount of the position of the left-end portion from the starting point, from an encoder amount of the position of the right-end portion from the starting point, an encoder amount equivalent to the width information of the paper P which is being conveyed is calculated. Moreover, based on the calculated encoder amount, the width information of the paper P which is being conveyed is acquired. Thus, the width information is updated to new width information. The position information of the end portion used for updating the width information at this time is initialized. 
     At step S 8 , the control unit  5  judges whether or not a jamming of the paper P that is being conveyed occurs. In other words, in a case that, during the conveying of the paper P, the paper P is not detected by the second paper sensor  19   b  even after a predetermined time has elapsed from a timing at which the paper P was detected by the first paper sensor  19   a , the control unit  5  judges that the third condition has been satisfied. In other words, the control unit  5  judges that the jamming of the paper P has occurred at a location such as the recording unit  20  (YES at step S 8 ), and the process advances to step S 9 . Whereas, in a case that the paper P is detected by the second paper sensor  19   b  within the predetermined time from the timing at which the paper P was detected by the first paper sensor  19   a , the control unit  5  judges that no jamming of the paper P has occurred (NO at step S 8 ), and the process advances to step S 10 . Here, the predetermined time is a time necessary for conveying the paper P from the first paper sensor  19   a  up to the second paper sensor  19   b  along the conveying direction A. In such manner, the jam sensor of the present teaching is formed by the first paper sensor  19   a  and the second paper sensor  19   b.    
     At step S 9 , the control unit  5  initializes the width information (width information) of the paper P and the position information of the end portion (end-portion position information) of the paper P stored in the RAM  103  similar to step S 3 . Sometimes, there is a shift in the position of the carriage  23  due to an external force which is exerted by the paper P hitting the carriage  23  or the recording head  21  when the jamming occurs, or due to an external force which is exerted by the paper or the user hitting the carriage  23  or the recording head  21  when the user removes the paper P that has caused jamming. In other words, sometimes the carriage  23  is shifted from a position indicated by the encoder amount of the linear encoder  35 . Therefore, it is necessary to update the width information by resetting the starting point of the encoder amount of the linear encoder  35  once again. Before updating the width information, at step S 9 , the width information of the paper P and the position information of the end portion of the paper P in the RAM  103  are initialized. Hereafter, the control unit  5  notifies the user that the jamming has occurred, by a notifying means which is not shown in the diagram, and jamming-resolution process is carried out by the user. As the jamming-resolution process has been completed, the process advances to step S 20 . Moreover, for executing the processing at step S 7  once again via step S 9 , the control unit  5  controls the carriage drive motor  40 M and firstly moves the carriage  23  to the third position. At this time, by setting the encoder amount to zero, the starting point of the encoder amount of the linear encoder  35  is set. Thereafter, the aforementioned processing at step S 7  is executed. 
     At steps from step S 10  to step S 20 , the control unit  5  controls the drive motor  30 M, the carriage drive motor  40 M, and the recording head  21  based on the recording job and the width information, and executes the recording processing of recording images on one or more than one paper P. In the recording processing, the reciprocating movement of the carriage  32  is controlled based on the width information acquired at step S 7 , and at step S 19  which will be described later. 
     Firstly, at step S 10 , the control unit  5  controls the drive motor  30 M and conveys the paper P only by a linefeed width. Next, at step S 11 , the control unit  5  judges whether or not a flushing operation is to be executed. More elaborately, the control unit  5  judges whether or not the number of times of the reciprocating movements of the carriage  23  has reached a predetermined number of times (such as five times). In a case that the control unit  5  has judged that the number of reciprocating movements of the carriage  23  has reached the predetermined number of times (YES at step S 11 ), the process advances to step S 12 , and in a case that the control unit  5  has judged that the number of reciprocating movements of the carriage  23  has not reached the predetermined number of times (NO at step S 11 ), the process advances to step S 13 . In the present embodiment, the flushing operation is carried out in a case that the number of reciprocating movements has reached the predetermined number of times. However, the flushing operation may be carried out in a case that the number of conveyed papers P has reached a predetermined number, or in a case that a predetermined time has elapsed after the previous flushing. 
     At step S 12 , the control unit  5  controls the carriage drive motor  40 M, and moves the recording head  21  to a flushing position at which the recording head  21  faces the waste-ink tray  42 . Thereafter, the control unit  5  controls the recording head  21  and jets the ink from the recording head  21  toward the waste-ink tray  42 . Since thickened ink in the recording head  21  is discharged in this manner, it is possible to prevent a jetting defect of the recording head  21  from occurring. Moreover, by moving the recording head  21  to the flushing position, the width detection sensor  50  is capable of detecting the left-end portion of the paper P. Therefore, position information of the left-end portion is stored in the RAM  103 . In other words, it is possible to acquire the position information of the end portion of the paper P. 
     At step S 13 , the control unit  5  judges whether or not images indicated by image data stored in the RAM  103  are to be recorded within predetermined end-portion areas L in the left-right direction  9  of the paper P. Here, as shown in  FIG. 9A  and  FIG. 9B , the predetermined end-portion areas L are areas on both of a left end and a right end of the paper P, and are areas each having a range shorter than half of the width in the left-right direction  9  of the paper P. As shown in  FIG. 9A  and  FIG. 9B , in a case that the image data includes data for recording images G 1  and G 2  in the predetermined end-portion areas L of the paper P, the control unit  5  judges that the images are to be recorded within the predetermined end portion areas L (YES at step S 13 ), and the process advances to step S 14 . Whereas, in a case that the image data does not include data for recording images in the predetermined end-portion areas L, the control unit  5  judges that the images are not to be recorded within the predetermined end portion areas L (NO at step S 13 ), and the process advances to step S 15 . 
     At step S 14 , a first recording operation is carried out. In other words, the control unit  5 , at the time of recording the image G 1 , controls the carriage drive motor  40 M, and moves the recording head  21  up to a recording position of the image G 1 , after positioning the width detection sensor  50  temporarily on the left side of the left-end portion of the paper P (in other words, the first position indicated by alternate long and two short dashes lines in  FIG. 9A ). Thereafter, the control unit  5  controls the recording head  21  and records the image G 1 . Accordingly, at the time of recording the image G 1  on the recording paper P, the width detection sensor  50  moves from the first position to a position facing the paper P, and the width detection sensor  50  is capable of detecting the position information of the left-end portion the paper P. Therefore, the position information of the left-end portion is stored in the RAM  103 . Moreover, the control unit  5 , at the time of recording the image G 2 , controls the carriage drive motor  40 M, and moves the recording head  21  up to a recording position of the image G 2 , after positioning the width detection sensor  50  temporarily on the right side of the right-end portion of the paper P (in other words, the second position indicated by alternate long and two short dashes lines in  FIG. 9B ). Thereafter, the control unit  5  controls the recording head  21  and records the image G 2 . Accordingly, at the time of recording the image G 2  on the recording paper P, the width detection sensor  50  moves from the second position to a position facing the paper P, and the width detection sensor  50  is capable of detecting the position information of the right-end portion of the paper P. Therefore, the position information of the right-end portion is stored in the RAM  103 . The position information of the left-end portion and the position information of the right-end portion are stored at step S 12  and step S 14  respectively in the RAM  103 . 
     At step S 15 , a second recording operation is carried out. In the first recording operation, the image recording is carried out after moving the width detection sensor  50  temporarily to one of the first position and the second position not facing the paper P. However, in the second recording operation, the image recording on the paper P is carried out upon moving the recording head  21  to a position facing the image recording position. In other words, the control unit  5  controls the carriage drive motor  40 M and moves the recording head  21  to the image recording position at which an image is recorded, which is a position facing an area between the predetermined end-portion areas L of the paper P. Moreover, the control unit  5  controls the recording head  21  to record an image in the area between the predetermined end-portion areas L of the paper P. In this case, since the width detection sensor  50  is facing the paper P all the time, the information of positions of end portions of the paper P is not detected. 
     Next, at step S 16 , the control unit  5  judges whether or not all the images to be recorded on one paper P have been recorded. In a case that all the images have not been recorded (NO at step S 16 ), the process returns to step S 8 , and aforementioned steps from step S 8  up to step S 16  are repeated. Whereas, in a case that all the images to be recorded on one paper P have been recorded (YES at step S 16 ), the process advances to step S 17 . At step S 17 , the control unit  5  controls the drive motor  30 M to rotate the conveying roller  55   a  and the paper discharge roller  56   a  continuously. Thus, the control unit  5  discharges the paper P to the paper discharge tray  16 . 
     Next, at step S 18 , the control unit  5  judges whether or not both of the position information of the left-end portion and the position information of the right-end portion have been stored in the RAM  103  for the recording operation on one paper P. In a case that the information of positions of both end portions have been stored in the RAM  103  (YES at step S 18 ), the process advances to step S 19 . Whereas, in a case that only one of the position information of the left-end portion and the position information of the right-end portion have been stored, or none of the position information of the left-end portion and the position information of the right-end portion has been stored (NO at step S 18 ), the process advances to step S 20 . 
     At step S 19 , the control unit  5  executes an update processing of the width information of the paper P. In other words, the control unit  5  acquires the width information of the paper P based on the position information of the left-end portion and the position information of the right-end portion, and stores the width information in the RAM  103 . In other words, the control unit  103  initializes the width information in the RAM  103  once, and stores (updates to) the acquired width information. Since the width information of the paper P is updated based on the information of the positions of the end portions of the paper P acquired during image recording, it is possible to maintain an image quality of an image recorded on the paper P while shortening the time period from receiving of the recording job to discharging the paper P on which the image has been recorded. At this time, in a case that each of the information of the position of the left-end portion and the information of the position of the right-end portion, or one of the information of the position of the left-end portion and the information of the position of the right-end portion has been stored in plurality, the width information is acquired based on an average value of the plurality of the information of the position of the end portion on the same side. Accordingly, it is possible to maintain effectively the quality of an image that is recorded on the paper P. 
     At step S 20 , the control unit  5  judges whether or not all the images involved in the recording job have been recorded on one or more than one paper P. In a case of recording on a plurality of papers for example, if the control unit  5  judges that images have not been recorded on all the papers P (NO at step S 20 ), the process returns to step S 5 , and paper feeding operation for carrying out image recording on the remaining papers is carried out. In a case that the aforementioned third predetermined condition has not been satisfied (in a case that no jamming has occurred) while processing from step S 5  onward is carried out, image recording is carried out on the paper P based on either the width information, in the recording job, updated at the first step S 7  or updated at step S 19 . Moreover, processing at step S 7  is a processing which is executed after a point of time at which the first to third predetermined conditions are satisfied and before an image is recorded on the first paper P based on the recording job. In other words, since the width information is initialized at step  51  and step S 3 , the process advances from step S 6  to step S 7 , and the acquiring processing is executed. Moreover, even if the width information is initialized at step S 9 , before an image is recorded on the paper P that is re-fed (before the image is recorded on the first paper P based on the recording job), the process advances to step S 7 , and the acquiring processing is executed. As the images are recorded on all the papers P at step S 20  (YES at step S 20 ), the process advances to step S 21 . 
     At step S 21 , the control unit  5  judges whether or not the subsequent recording job has been received. In a case that the subsequent recording job has been received (YES at step S 21 ), the process returns to step S 2 , and processing at steps from step S 2  to step S 20  similar to the aforementioned steps is executed. At this time, since the subsequent recording job has been received, the processing at step S 4  is omitted. Moreover, even in a case that the aforementioned second predetermined condition (detachment and attachment of the paper feeding tray  15 ) and the third predetermined condition have not been satisfied while the processing at steps from step S 2  onward is being executed after the subsequent job has been received, the image recording is carried out on the paper P based on the width information updated at step S 7  in the previous job or the width information updated at step S 19  in the previous job. In a case that the subsequent recording job has not been received at step S 21  (NO at step S 21 ), the image recording operation is finished. 
     As described heretofore, according to the printer unit  11  according to the present embodiment, even at the time of recording images on the plurality of papers P based on the plurality of recording jobs, after the processing at step S 7  is executed for the first recording job, the width information is not updated in the acquiring processing at step S 7  until the first to third predetermined conditions are satisfied. Therefore, an image is recorded on the paper P based on the width information before updating. Accordingly, it is not necessary to update the width information for each recording job, and with respect to a recording job for which updating of the width information is not required, it is possible to shorten the time period from receiving the recording job to discharging the paper P on which the image has been recorded. 
     Moreover, as a detection signal indicating detachment and attachment of the paper feeding tray  15  is received from the attachment/detachment sensor  18 , the control unit  5  judges that the second predetermined condition has been satisfied. Thereafter, the acquiring processing at step S 7  is executed. In other words, as the condition related to a change in the size of the paper P is satisfied, the acquiring processing is executed. In a case that the paper feeding tray  15  is detached and attached by the user, papers P are sometimes replaced with another paper having another size. According to the above described embodiment, even if there is a change in the size of the paper P due to replacing the paper P, it is possible to update the width information to new width information of the paper P that has been newly placed in the paper feeding tray  15 . Therefore, it is possible to record an image on the P based on the width information which has been updated. 
     Moreover, a small backlash or gap is provided between the paper feeding tray  15  and the casing  14 , so that the paper feeding tray  15  can be detached from and attached to the casing  14  smoothly. In a case that the paper feeding tray  15  is detached from and attached to the casing  14 , the position of the paper feeding tray  15  with respect to the casing  14  differs between before the detachment from the casing  14  and after the attachment to the casing  14 , due to the backlash. Accordingly, even if the standard size, manufacturer, and the like, of the plurality of papers P contained in the paper feeding tray  15 , are the same between before the detachment from the casing  14  and after the attachment to the casing  14 , the position of the paper P with respect to the conveying path  27  in the left-right direction  9  differs between before the detachment from the casing  14  and after the attachment to the casing  14 . Such a position shift of the paper P in the left-right direction  9  caused by the backlash is likely to be greater than a position shift of the paper Pin the left-right direction  9  within the paper feeding tray  15 . Moreover, even if the standard size of the papers P is the same, the width of the paper p slightly differs depending on the manufacturers. Therefore, in a case that the manufacturer of the plurality of papers p contained in the paper feeding tray  15  before the detachment is different from the manufacturer of the plurality of papers p contained in the paper feeding tray  15  after the attachment, the position of the paper P with respect to the conveying path  27  in the left-right direction  9  is likely to differ between before the detachment from the casing  14  and after the attachment to the casing  14 . As described above, the detachment and attachment of the paper feeding tray  15  with respect to the casing  14  is likely to cause the great position shift of the paper P with respect to the conveying path  27  in the left-right direction  9 . Accordingly, in the above described embodiment, the width information of the paper P is updated when the detection signal indicating the detachment and attachment of the paper feeding tray  15  is received. By doing this, it is possible to prevent the image quality from being degraded due to the great position shift of the paper P with respect to the conveying path  27  in the left-right direction  9 , while shortening the time period from receiving the recording job to discharging the paper P on which the image has been recorded. 
     In the above described embodiment, a judgment that the second predetermined condition has been satisfied was made by detecting detachment and attachment of the paper feeding tray  15  based on the detection signal from the attachment/detachment sensor  18 . However, instead of the attachment/detachment sensor  18 , a number-of-sheets sensor which detects the number of papers P in the paper feeding tray  15  may be provided. In this modified example, when there is a change, in the number of sheets detected by the number-of-sheets sensor, of more than a predetermined number of sheets (more than one sheet), namely, in a case that the number of papers P in the paper feeding tray  15  has increased above or decreased below a predetermined number at a time, the control unit  5  may judge that the second predetermined condition has been fulfilled similarly as mentioned heretofore. Moreover, after the judgment has been made, the aforementioned acquiring processing at step S 7  may be executed. As a case in which the number of papers Pin the paper feeding tray  15  changes to more than one at a time, a case, in which the user changes the size of the paper Pin the paper feeding tray  15  to a paper P of another size, can be considered. In this modified example, in a case that the size of the paper P is changed due to replacing the paper P, it is possible to update the width information to new width information of the paper P which has been newly placed in the paper feeding tray  15 , similarly as in the embodiment described above. Therefore, it is possible to record an image on the recording paper P based on the width information that has been updated. In a case of using the number-of-sheets sensor, an arrangement may be such that the paper feeding tray  15  is not detachable from the casing  14 . In other words, the paper feeding tray  15  may be fixed to the casing  14 . Moreover, as another modified example, without providing the attachment/detachment sensor  18  or the number-of-sheets sensor, a judgment that the predetermined condition has been fulfilled may be made based on information inputted from the user. In other words, in a case that information related to the change in the size of the paper P has been inputted by the user by operating the operating section of the multi-function peripheral  10 , an arrangement may be made such that the control unit  5  judges that the second predetermined condition has been fulfilled. Thereafter, the acquiring processing at step S 7  mentioned above may be carried out. Even with such arrangement, it is possible to achieve an effect similar to the effect mentioned above. 
     As still another modified example, in a case that the paper feeding tray  15  is configured not to be detachable from the casing  14 , the control unit  5  may judge that the second predetermined condition has been satisfied when no paper P is contained in the paper feeding tray  15 , similarly as aforementioned. More elaborately, in a case that the first paper sensor  19   a  does not detect the front end of the paper P until a predetermined time (time until the front end of the paper P conveyed at a predetermined conveying velocity from the paper feeding tray  15  is detected by the first paper sensor  19   a ) has elapsed after a paper-feeding start time at which the paper P is fed from the paper feeding tray  15  to the conveying path  27  by the paper feeding roller  31 , the control unit  5  judges that the paper P has not been contained in the paper feeding tray  15  (in other words, the second predetermined condition has been satisfied). In a case that it is possible to detect conveying amount of the paper P by the paper feeding roller  31 , if the first paper sensor  19   a  does not detect the paper P in spite of a fact that the paper feeding roller  31  rotated by an amount equivalent to an amount necessary for conveying the paper P in the paper feeding tray  15  up to a position facing the first paper sensor  19   a , the control unit  5  may judge that the paper P has not been contained in the paper feeding tray  15 . Thus, an empty-detection means of the present teaching is formed by the first paper sensor  19   a  and the control unit  5 . In the present modified example, the judgment that the paper feeding tray  15  is empty is made at the aforementioned step S 5 , and in a case that the paper P has not been contained, initialization of the width information is carried out. Moreover, thereafter, the acquiring processing at the aforementioned step S 7  may be executed. If the paper P has not been contained in the paper feeding tray  15 , the user newly loads the papers Pin the paper feeding tray  15 . Even if the size of the papers P is changed when the papers P are loaded, it is possible to update to the width information of the papers P that have been newly loaded, similarly in the aforementioned embodiment. Therefore, it is possible to record an image on the recording paper P based on the width information that has been updated. The abovementioned modified example is also applicable to a paper feeding tray (including a manual feed tray which is provided between the paper feeding tray  15  and the first paper sensor  19   a  of the conveying path  27 ) which is provided separately from the paper feeding tray  15 . Moreover, a sensor which is capable of inputting a signal, directly to the control unit  5 , that indicates that the paper P has not been contained in the paper feeing tray  15  may be provided to the paper feeding tray  15 . In this case, the control unit  5  may judge that the second predetermined condition has been fulfilled based on the signal (the signal which indicates that no paper P has not been contained) inputted from the sensor. Even in this case, it is possible to achieve an effect similar to the abovementioned effect. 
     Moreover, when jamming of the paper P occurs in the conveying path  27 , the control unit  5  judges that the third predetermined condition has been satisfied. Therefore, when the jamming occurred, the acquiring processing is carried out. Moreover, when the power supply is put ON, the control unit  5  judges that the first predetermined condition has been satisfied. Accordingly, even if the user replaces the papers P when the power supply is OFF, because the width information is updated to that of the replaced paper P, it is possible to record an image on the recording paper P based on the updated width information. 
     Moreover, in a case that the image G 1  (or the image G 2 ) is to be recorded in the predetermined end-portion area L, the control unit  5  controls the carriage drive motor  40 M such that the width detection sensor  50  is arranged at the first position (or the second position). Accordingly, it becomes easy to achieve the information of positions of the end portions of the paper P. Therefore, it is possible to maintain, more effectively, the quality of the image recorded on the recording paper P. 
     The embodiments of the present teaching have been described heretofore. However, the present teaching is not restricted to the embodiments described heretofore, and various modifications without departing from the claims described are possible. For instance, in the aforementioned embodiments, the width information of the paper P acquired at step S 7  and step S 19  was stored in the RAM  103 . However, the width information of the paper P may be stored in another storage unit such as a flash memory. Moreover, even when an image is to be recorded in the end-portion area L, the recording head  21  may be moved to a recording position at which the image is to be recorded, without being moved to the first position or to the second position. Even in this case, when the width detection sensor  50  is moved to a position at which the width detection sensor  50  can detect the end portions of the paper P, the information of the positions of the end portions detected by the width detection sensor  50  may be stored in the RAM  103 . Moreover, in the recording operation of recording an image on a paper P, even if the width detection sensor  50  detects the information of the positions of the end portions, the information of the positions of the end portions detected by the width detection sensor  50  may not be stored in the RAM  103 . Moreover, only one of the first to third predetermined conditions mentioned above may be adopted, and when that predetermined condition has been satisfied, updating of the width information may be carried out after initializing the width information. Moreover, the width information to be updated may be overwritten without initializing. 
     Moreover, the moving mechanism  40  may move the carriage  23  together with the recording head  21  in an intersecting direction which is slightly inclined from a direction orthogonal to the conveying direction A. In this case, the width information of the paper P in the intersecting direction is to be acquired. Moreover, it may be any conveying mechanism (such as a belt conveying mechanism) provided that the conveying mechanism is capable of conveying the paper P in the conveying direction A. 
     Examples, in which the present teaching is applied to a recording apparatus for recording an image by jetting inks from the nozzles, have heretofore been described. However, the present teaching is also applicable to a recording apparatus other than printer, which jets liquids other than ink from the nozzles.