JP2014019093A - Recording device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording device capable of accurately detecting an end of a recording medium in a main scanning direction using an optical sensor in both of a forward path and a return path of a main scanning direction of a carriage.SOLUTION: A recording device includes a recording head discharging ink from a plurality of nozzles and recording an image in a recording medium and an optical sensor disposed on a conveyance direction downstream side of a nozzle formed on an uppermost stream side of the conveyance direction of a plurality of nozzles, and further includes a carriage movable in a main scanning direction. Discharge amount of ink is calculated from image data to be used for single scanning of the carriage. When the discharge amount of ink discharged to an end of main scanning direction of the recording medium exceeds a threshold, the level of a signal transmitted from the optical sensor is adjusted.

Description

  The present invention relates to a recording apparatus capable of detecting the edge of a recording medium.

2. Description of the Related Art Conventionally, a recording apparatus that detects an end of a recording medium such as paper using an optical sensor provided in a carriage that moves in the main scanning direction is known. This type of recording apparatus determines the position of the recording medium in the main scanning direction from the end of the recording medium detected using an optical sensor. Then, based on the determined position of the recording medium in the main scanning direction, the recording apparatus determines the ejection range of the liquid in the main scanning direction by the recording head provided in the carriage. Then, the liquid is ejected from the recording head within the determined range, whereby an image is recorded on the recording medium.
For example, Patent Document 1 describes a recording apparatus that includes a paper detector that is disposed on a carriage that reciprocates in the main scanning direction and detects the edge of the paper. Specifically, the paper detector is disposed on the upstream side in the paper transport direction in the dot forming element array formed on the recording head in the carriage.

JP2003-260788

  However, in the recording apparatus described in Patent Document 1, there is a possibility that the end of the paper in the main scanning direction cannot be accurately detected. As an example, there is a case where a paper detector is disposed on the carriage in the forward direction direction from the recording head, and liquid is ejected from the recording head as the carriage moves in the backward direction. In this case, there is a possibility that the position of the edge cannot be accurately detected using the paper detector at the edge of the sheet including the discharge area where the liquid is discharged from the recording head.

  An object of the present invention is to provide a recording apparatus that can accurately detect an end of a recording medium in the main scanning direction using an optical sensor in both the forward path and the return path in the main scanning direction of the carriage. .

  (1) A recording apparatus according to the present invention includes a conveying unit that conveys a recording medium in a conveying direction, a recording head that includes a plurality of nozzles, and records an image by ejecting ink from the plurality of nozzles onto the recording medium; Optical sensor for detecting the position of the side end in the main scanning direction, which is disposed on the downstream side in the transport direction from the nozzle formed on the most upstream side in the transport direction among the plurality of nozzles, and irradiates light toward the recording medium The position of the side edge of the recording medium is detected by a carriage that includes the recording head and the optical sensor, moves in a main scanning direction orthogonal to the transport direction, and a signal level emitted from the optical sensor. Side edge detection means, calculation means for calculating the discharge amount of the ink discharged to the side edge portion, and when the discharge amount calculated by the calculation means exceeds a threshold value and the number of optical sensors is small. Both when located on the side edge of the recording medium, the signal level that is emitted from the optical sensor is characterized by comprising a control means for adjusting to exceed a predetermined amount.

  (2) The control means is configured to detect the optical sensor when the optical sensor reaches a position outside the recording medium and farthest from the side edge of the recording medium among the side edges of the recording medium. It is characterized by adjusting the signal level emitted from the.

  (3) The optical sensor has an opening of the predetermined distance, and emits light toward the recording medium through the opening and receives light reflected by the recording medium, and the control means includes the optical sensor. However, it is characterized in that the signal level emitted from the optical sensor is adjusted when it reaches a position outside the recording medium and at the predetermined distance from the side edge of the recording medium.

  (4) The control means is characterized in that when the optical sensor is located at a position other than the end of the recording medium, the optical sensor is turned off.

  (5) The control means adjusts the signal level by increasing the light emission amount of the optical sensor from a predetermined reference value.

  (6) The predetermined reference value is the light emission amount when the signal level is not adjusted by the control means.

  (7) The threshold value is defined by the light reflectance of the recording medium.

  (8) The predetermined amount is a value corresponding to about 60% of a saturation value of a signal level emitted from the optical sensor.

According to the present invention, the end of the recording medium in the main scanning direction can be accurately detected using the optical sensor in both the forward path and the return path in the main scanning direction of the carriage.

1 is an external view illustrating an external configuration of a multifunction machine 1 according to an embodiment of the present invention. 2 is a schematic cross-sectional view illustrating a main configuration of a printer unit 2. FIG. 3 is a partial plan view showing a main configuration of a recording unit 50. FIG. (A) It is a schematic diagram which shows the main structures of the linear encoder 113. FIG. (B) It is a schematic diagram of the pulse signal produced | generated by the change of the light reception state of each light receiving element 208,210. 6 is a bottom view of the carriage 53 showing the relationship between the nozzle formation surface of the recording head 51 and the media sensor 52. FIG. FIG. 6 is a schematic diagram showing the ejection amount of ink ejected from each nozzle 55 to each unit region U. 5A is a schematic diagram illustrating the relationship between the platen 54, the ribs 56, and the paper P and the scanning of the carriage 53 in the forward direction. FIG. (B) A graph showing the relationship between the signal level from the media sensor 52 and the number of encoder slits 204 in the encoder strip 77. 1 is a block diagram illustrating an overall configuration of a multifunction machine 1. FIG. It is a flowchart which shows the process which the control part 100 performs in the 1st embodiment. (A) is a schematic diagram showing the relationship between the platen 54, the ribs 56, and the paper P on which ink is ejected on the side edge and the scanning of the carriage 53 in the forward direction. (B) A graph showing the relationship between the signal level from the media sensor 52 and the number of encoder slits 204 in the encoder strip 77 when the light emission amount of the media sensor 52 is not adjusted. (C) Light emission of the media sensor 52. 6 is a graph showing the relationship between the signal level from the media sensor 52 and the number of encoder slits 204 in the encoder strip 77 when the amount is adjusted. (A) It is a schematic diagram which shows the relationship between the reflected light from the rib 56, and the light-receiving part 115. FIG. FIG. 6B is a schematic diagram showing the relationship between the reflected light from the platen 54 and the light receiving unit 115. It is a flowchart which shows the process which the control part 100 in the 2nd embodiment performs. 6 is a schematic diagram illustrating a side end portion of a sheet P in detail. FIG. It is a flowchart which shows the light emission amount adjustment process (S1014) of the media sensor 52 which the control part 100 performs. (A) is a schematic diagram showing the relationship between the platen 54, the ribs 56, and the paper P on which ink is ejected on the side edge and the scanning of the carriage 53 in the forward direction. (B) A graph showing the relationship between the signal level from the media sensor 52 and the number of encoder slits 204 in the encoder strip 77. (C) A graph showing the relationship between the signal level from the media sensor 52 and the number of encoder slits 204 in the encoder strip 77.

  Hereinafter, a multifunction machine 1 according to a preferred embodiment of the present invention will be described with reference to the drawings. In addition, embodiment is only an example of this invention, and it cannot be overemphasized that embodiment of this invention can be changed suitably in the range which does not change the summary of this invention.

  The multifunction device 1 is installed and used in the state shown in FIG. In the present embodiment, three directions indicated by arrows in FIG. 1 are a vertical direction 400, a front-rear direction 200, and a left-right direction 300. The three directions shown in FIG. 1 are the same in other drawings.

<Overview of MFP 1>
First, the external appearance of the multifunction device 1 will be described with reference to FIG. FIG. 1 shows an external configuration of a multifunction machine 1 according to an embodiment of the present invention. As shown in FIG. 1, a multifunction machine 1 as an example of the present invention includes a printer unit 2 at a lower portion and a scanner unit 3 at an upper portion. The multifunction device 1 has a printer function, a scanner function, a copy function, and a facsimile function. Among the functions of the multifunction device 1, functions other than the printer function are arbitrary. Therefore, for example, the present invention may be implemented in a single-function printer that does not have the scanner unit 3 and has no scanner function or copy function. An operation panel 4 is provided at the upper front of the multifunction device 1. The operation panel 4 includes various operation buttons and a liquid crystal display unit. When the operation panel 4 is operated by the user, the multifunction device 1 controls the printer unit 2 and the scanner unit 3 to execute each function of the multifunction device 1. The multifunction device 1 operates based on an operation instruction from the operation panel 4. The multifunction device 1 can execute each function of the multifunction device 1 by a user operating an external terminal such as a personal computer connected to the multifunction device 1 from the outside.

  An opening 7 is formed on the front side of the printer unit 2. A paper feed cassette 5 and a paper discharge tray 6 are disposed in the printer unit 2 through the opening 7.

<Configuration of Printer Unit 2>
Next, the main configuration of the printer unit 2 will be described with reference to FIG. FIG. 2 is a schematic cross-sectional view showing the main configuration when the printer unit 2 is viewed from the left-right direction 300. The printer unit 2 includes a paper feed cassette 5, a paper feed unit 20, a first transport unit 40, a recording unit 50, a second transport unit 60, and a paper discharge tray 6 as main components.

<Paper cassette>
In FIG. 2, the paper feed cassette 5 can store various sizes of paper. An inclined portion 21 is provided at the rear end portion of the paper feed cassette 5. Further, the paper feed cassette 5 can be moved in the front-rear direction 200 in the opening 7 by being operated by the user, that is, is detachable from the printer unit 2.

<Paper Feeder 20>
As shown in FIG. 2, the printer unit 2 is provided with a paper feeding unit 20 that feeds the paper placed in the paper feeding cassette 5. The paper feed unit 20 includes a paper feed roller 22, a paper feed arm 23, a drive transmission mechanism 24, and a base shaft 25. The paper feed roller 22 feeds the paper placed on the paper feed cassette 5 toward the transport roller 41. Further, the paper feed roller 22 is pivotally supported at the front end portion of the paper feed arm 23. A part of a drive transmission mechanism 24 connected to the paper feed roller 22 and meshed with a plurality of gears is disposed in the paper feed arm 23. The drive transmission mechanism 24 transmits the driving force of the transport motor 108 (see FIG. 8). That is, the paper feed roller 22 is rotated via the drive transmission mechanism 24 when the carry motor 108 is driven.

  The paper feed arm 23 rotates around a base shaft 25 provided at the other end of the paper feed arm 23 so that the paper feed roller 22 can come into contact with and separate from the paper placed in the paper feed cassette 5. Move. The paper feed roller 22 pivotally supported at the tip of the paper feed arm 23 comes into contact with the surface of the paper P placed on the paper feed cassette 5 by being biased by its own weight or by a spring or the like. In this state, the paper feed roller 22 rotates to feed the paper P in contact with the paper feed roller 22 to the inclined portion 21. When the leading end of the sheet P is in contact with the inclined portion 21 and is guided upward, the sheet P that contacts the sheet feeding roller 22 is separated from the lower sheet that contacts the sheet P by frictional force or the like. . Then, the paper P separated from the lower paper and in contact with the paper feed roller 22 is fed to the paper transport path 30.

<Paper transport path 30>
The sheet conveyance path 30 is formed by an outer guide member 31 and an inner guide member 32 that are separated by a predetermined distance. The outer guide member 31 is provided from the rear end portion of the paper feed cassette 5 to the first transport unit 40 described later. The outer guide member 31 has a curved portion that is curved so that the paper P fed to the rear of the apparatus by the paper feed roller 22 faces the front of the apparatus. The inner guide member 32 also has a curved portion like the outer guide member 31. The outer guide member 31 and the inner guide member 32 are provided in the printer unit 2 with their curved portions facing each other. That is, the paper P fed by the paper feed roller 22 reaches the first transport unit 40 via the paper transport path 30 formed by the outer guide member 31 and the inner guide member 32.

<First transport unit 40>
As shown in FIG. 2, the paper P fed through the paper transport path 30 by the paper feed roller 22 is fed to the first transport unit 40. The first transport unit 40 includes a transport roller 41 and a driven roller 42. The transport roller 41 is rotated by the transport motor 108. A driven roller 42 is provided so as to be in pressure contact with the roller surface of the conveying roller 41. That is, the paper P fed by the paper feed roller 22 is sandwiched between the transport roller 41 and the driven roller 42. When the transport roller 41 is rotated by the transport motor 108 with the paper P being sandwiched, the paper P is transported downstream in the transport direction (that is, forward) and transported to the recording unit 50 described later.

<Recording unit 50>
As shown in FIG. 2, a recording unit 50 is provided on the downstream side of the conveyance roller 41 in the conveyance direction. The recording unit 50 includes a recording head 51, a media sensor 52, and a carriage 53. The recording head 51 and the media sensor 52 include a carriage 53. When the CR (carriage) motor 110 is driven, the carriage 53 is reciprocated in the main scanning direction orthogonal to the transport direction (that is, the vertical direction in FIG. 2 and the left-right direction 300). The recording head 51 is supplied with ink from an ink cartridge (not shown) arranged in the printer unit 2. The recording head 51 ejects the supplied ink as fine ink droplets. Detailed descriptions of the recording head 51 and the media sensor 52 will be described later.

  As shown in FIG. 2, the platen 54 is provided so as to face the recording head 51 and the media sensor 52. The platen 54 is provided over the range in which the paper passes in the reciprocating range of the carriage 53. The width of the platen 54 in the main scanning direction is larger than the width of the largest sheet that can be conveyed by the printer unit 2 in the main scanning direction, and both ends of the sheet P in the main scanning direction always pass over the platen 54. The platen 54 supports the paper P that is transported by the transport roller 41. That is, while the carriage 53 is reciprocated, ink droplets are ejected from the recording head 51, whereby an image or the like is recorded on the paper supported by the platen 54. The detailed description of the platen 54 will be described later.

<Second transport unit 60>
As shown in FIG. 2, the paper P transported by the first transport unit 40 is transported to the second transport unit 60. The second transport unit 60 includes a paper discharge roller 61 and a spur 62. The paper discharge roller 61 is rotated by the driving force transmitted when the transport roller 41 rotates. A spur 62 is provided so as to be in pressure contact with the roller surface of the paper discharge roller 61. The spur 62 comes into contact with the surface of the paper P on which an image or the like has been recorded by the recording unit 50. That is, the paper P conveyed by the conveyance roller 41 is sandwiched between the paper discharge roller 61 and the spur 62. When the paper discharge roller 61 is rotated by the transport roller 41 while the paper P is sandwiched by the second transport unit 60, the paper P is transported downstream in the transport direction.

  A paper discharge tray 6 is provided on the downstream side in the transport direction of the second transport unit 60. That is, when the paper P transported downstream in the transport direction by the second transport unit 60 is released from the nipping by the second transport unit 60, the paper P is discharged onto the paper discharge tray 6.

<Driving of carriage 53>
Next, a main configuration for moving the carriage 53 in the main scanning direction will be described with reference to FIG. FIG. 3 is a partial plan view showing the main configuration of the recording unit 50. The printer unit 2 is provided with two guide frames 70 and 71 arranged at a distance in the transport direction (that is, the front-rear direction 200). The two guide frames 70 and 71 are formed so as to extend in the main scanning direction (that is, the left-right direction 300). The carriage 53 is placed so as to reciprocate in the main scanning direction so as to straddle the guide frames 70 and 71. At this time, the carriage 53 slides on the guide frames 70 and 71. The guide frame 70 provided on the upstream side (that is, the rear side) in the conveyance direction of the paper P is formed so that the length in the main scanning direction is longer than the reciprocating range of the carriage 53. Further, the upper surface of the guide frame 70 slidably supports the upstream end portion of the carriage 53.

  The guide frame 71 provided on the downstream side in the conveyance direction of the paper P is formed so that the length in the main scanning direction is substantially the same as that of the guide frame 70. An edge portion 72 that supports the downstream end portion of the carriage 53 is bent upward at a substantially right angle. The carriage 53 is slidably supported on the upper surface of the guide frame 71, and the edge portion 72 is sandwiched between rollers (not shown) provided in the carriage 53. Accordingly, the carriage 53 is slidably supported on the guide frames 70 and 71 and reciprocates in the main scanning direction with the edge portion 72 of the guide frame 71 as a reference.

A belt driving mechanism 73 is provided on the upper surface of the guide frame 71. The belt drive mechanism 73 includes a drive pulley 74, a driven pulley 75, and a timing belt 76. The drive pulley 74 is provided at the right end portion of the guide frame 71. A driving force is transmitted to the shaft of the driving pulley 74 from the CR motor 110 (see FIG. 8). That is, the drive pulley 74 is rotated by the CR motor 110. The driven pulley 75 is provided at the left end portion of the guide frame 71. The timing belt 76 is an endless belt having teeth on the inside. The timing belt 76 is provided on the guide frame 71 so as to bridge the driving pulley 74 and the driven pulley 75. That is, when the driving pulley 74 is driven by the CR motor 110, the timing belt 76 moves circumferentially by the rotation of the driving pulley 74. At this time, the driven pulley 75 is rotated by a timing belt 76 that makes a circumferential motion. The drive pulley 74 may be provided at the left end portion of the guide frame 71 and the driven pulley 75 may be provided at the right end portion of the guide frame 71. The guide frame 71 is provided with a strip-shaped encoder strip 77 along the edge 72.
A timing belt 76 is connected to the carriage 53. The carriage 53 reciprocates on the guide frames 70 and 71 with the edge 72 as a reference by the circumferential movement of the timing belt 76. Accordingly, the recording head 51 and the media sensor 52 are mounted on the carriage 53, and the recording head 51 and the media sensor 52 can reciprocate in the main scanning direction.

  Next, the main configuration of the linear encoder 113 will be described with reference to FIG. FIG. 4A is a schematic diagram showing the main configuration of the linear encoder 113. The carriage 53 includes a sensor unit 201 in which a light emitting member 202 and a light receiving member 203 are arranged with an encoder strip 77 interposed therebetween. The sensor unit 201 constitutes a linear encoder 113 together with the encoder strip 77.

  As shown in FIG. 4A, the linear encoder 113 includes an encoder strip 77 in which encoder slits 204 are formed at a predetermined interval, and a sensor unit 201. The sensor unit 201 includes a light emitting member 202 and a light receiving member 203. The encoder strip 77 is arranged so as to be positioned between the light emitting member 202 and the light receiving member 203. The light emitting member 202 includes two light emitting elements (A phase light emitting element 207 and B phase light emitting element 208), and the light receiving member 203 includes two light receiving elements (A phase light receiving element 209 and B phase light receiving element 210). Yes. Here, the light emitted from the A phase light emitting element 207 is received by the A phase light receiving element 209, and the light emitted from the B phase light emitting element 208 is received by the B phase light receiving element 210.

  The sensor unit 201 reciprocates in the main scanning direction as the carriage 53 moves. Here, depending on the relative positional relationship between the sensor unit 201 and the encoder strip 77, the light receiving elements 209 and 210 may receive light from the light emitting elements 207 and 208 and may not receive light. Thereby, the sensor part 201 produces | generates the below-mentioned pulse signal. In FIG. 4A, light from the A-phase light emitting element 207 passes through the encoder strip 77 and is received by the A-phase light receiving element 209, and light from the B-phase light emitting element 208 is blocked by the encoder strip 77 and B A state in which light is not received by the phase light receiving element 210 is shown.

  Next, a pulse signal generated by the sensor unit 201 will be described with reference to FIG. FIG. 4B is an explanatory diagram of a pulse signal generated by a change in the light receiving state of each light receiving element. As shown in FIG. 4B, the sensor unit 201 generates two types of pulse signals that are shifted from each other by a constant period in accordance with the movement of the carriage 53. Specifically, the sensor unit 201 includes an encoder A phase signal (encA) generated by a change in the light receiving state at the A phase light receiving element 209 and an encoder generated by a change in the light receiving state at the B phase light receiving element 210. A B phase signal (encB) is generated. Then, the encoder signals encA and encB of the phases A and B have the phase of encB advanced by a certain period with respect to encA during the scanning of the carriage 53 in the forward direction (that is, from left to right in the left-right direction 300 in FIG. 1). In the scanning of the carriage 53 in the direction (that is, from left to right in the left-right direction 300 in FIG. 1), the phase of encB is delayed by a certain period with respect to encA. The control unit 100 described later detects the moving direction of the carriage 53 based on the phase difference between encB and encA.

  In addition, the control unit 100 detects the position of the carriage 53 in the main scanning direction by counting the pulse signals generated by the sensor unit 201. That is, the reciprocation of the carriage 53 is controlled by the control unit 100 based on the pulse signal generated from the linear encoder 113.

<Recording head 51>
FIG. 5 is a bottom view of the carriage 53 showing the relationship between the nozzle formation surface of the recording head 51 and the media sensor 52. A plurality of nozzles 55 are provided on the lower surface of the recording head 51 along the main scanning direction (that is, the left-right direction 300) and the conveyance direction (that is, the front-rear direction 200, the sub-scanning direction). The recording head 51 causes ink from each nozzle 55 to land on the paper P at predetermined intervals in the main scanning direction and the transport direction by ink discharge control described later. For example, when the main scanning direction resolution and the sub-scanning direction resolution are both 300 dpi (that is, the above-mentioned predetermined interval is 300 dpi), 1 on the paper P is virtually each in the main scanning direction and the sub-scanning direction. A plurality of unit regions U (see FIG. 6) partitioned in a lattice shape having a length of / 300 inches are defined. The control unit 100 uses the unit area U to calculate the ink ejection amount in advance before starting the recording process as will be described later. Note that the pitch, the number, and the like of each nozzle 55 are appropriately set in consideration of the desired recording performed by the multifunction machine 1.

<Media sensor 52>
As shown in FIG. 5, a media sensor 52 is mounted on the carriage 53. The media sensor 52 includes a housing having an opening 57 having a diameter r, and a light emitting portion 114 made of a light emitting diode and a light receiving portion 115 made of a phototransistor or the like are arranged in the housing (see FIG. 8). The light emitting unit 114 of the media sensor 52 is configured such that light is emitted toward the platen 54 and the light receiving unit 115 receives reflected light of the light. The light emitted from the light emitting unit 114 and the reflected light received by the light receiving unit 115 pass through the opening 57.

  As shown in FIG. 3, the platen 54 is provided with a plurality of ribs 56 that extend in a direction parallel to the conveyance direction of the paper P and are spaced apart in the main scanning direction. The ribs 56 protrude upward from the platen 54 (that is, the direction perpendicular to the paper surface in FIG. 3), that is, toward the carriage 53, and when the paper P passes, the upper surfaces of the plurality of ribs 56 come into contact with the paper P.

  The color of the platen 54 is configured by a color having a different light reflectance from the sheet P, which is generally widely used white, such as black. For example, when the sheet P does not exist, that is, the signal level from the media sensor 52 when the light receiving unit 115 receives the reflected light from the platen 54 having a lower reflectance than the sheet P is set as the value A. Then, when the paper P is present, the light receiving unit 115 receives the reflected light from the paper P having a higher reflectance than the platen 54, so that the signal level from the media sensor 52 is a value B higher than the value A. Become. Therefore, the control unit 100 described later can detect the presence or absence of the paper P from the difference in the amount of reflected light received by the media sensor 52.

  With reference to FIG. 7, detection of an edge (hereinafter referred to as a side edge) of the paper P in the main scanning direction performed by the control unit 100 described later will be described. FIG. 7A is a schematic diagram showing the relationship between the platen 54, the rib 56, and the paper P and the scanning of the carriage 53 in the forward direction (that is, from the left to the right in the left-right direction 300 in FIG. 1). FIG. 7B is a graph showing the relationship between the signal level from the media sensor 52 and the number of encoder slits 204 in the encoder strip 77. For convenience of explanation, the case of scanning in the forward direction of the carriage 53 will be described with reference to FIG. 7, but it goes without saying that the case of scanning in the backward direction of the carriage 53 is the same.

  As shown in FIG. 7A, the media sensor 52 mounted on the carriage 53 moves in the forward direction as the carriage 53 moves while irradiating light from the light emitting unit 114. As shown in FIG. 7B, when the media sensor 52 is positioned immediately above the platen 54, the signal level from the media sensor 52 is a value A lower than a predetermined threshold value. When the media sensor 52 is positioned immediately above the rib 56, the signal level from the media sensor 52 is slightly higher than the value A (for example, a value between the value A and the value C). When the media sensor 52 passes just above the left end of the paper P, the waveform of the signal level from the media sensor 52 shows a steep rise. This is because light emitted from the light emitting unit 114 of the media sensor 52 and reflected on the surface of the platen 54 or the rib 56 is gradually reflected on the surface of the paper P as the carriage 53 moves. It is. Further, when the carriage 53 moves and the media sensor 52 is positioned immediately above the paper P, the signal level from the media sensor 52 becomes a value B higher than the value A. Further, when the media sensor 52 passes right above the right end of the paper P, the signal level from the media sensor 52 shows a waveform opposite to that when the media sensor 52 passes right above the left end. That is, the waveform of the signal level from the media sensor 52 shows a steep fall. The control unit 100 to be described later uses a predetermined value C between the values A and B as a threshold, and the leftmost position (the minimum number of encoder slits 204) exceeding the threshold C is the left end of the paper P, and the rightmost (encoder slit 204). The position of (number maximum) is detected as the right end of the paper P.

<Control unit 100>
FIG. 8 is a block diagram illustrating a configuration of the control unit 100 of the printer unit 2. As shown in FIG. 8, the control unit 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, and an EEPROM (Electrically Erasable Programmable Memory) 104. It is configured as a microcomputer. The CPU 101, ROM 102, RAM 103, and EEPROM 104 are connected to an ASIC (Application Specific Integrated Circuit) 106 via a bus 105.

  The ROM 102 stores a program for controlling various operations of the printer unit 2 and the like. The RAM 103 is used as a storage area or a work area for temporarily recording various data used when the CPU 101 executes the program. The EEPROM 104 stores settings, flags, and the like that should be retained even after the power is turned off.

  The RAM 103 stores image data relating to an image recorded on the paper P input from a personal computer or the like connected to the multifunction device 1. The CPU 101 analyzes image data described in a page description language (PDL: Page Description Language) or the like. Then, the CPU 101 adds the ink ejection amount for each unit region U (see FIG. 6) to calculate the ink ejection amount ejected from the image data.

  The amount of ink discharged to each unit region U will be described with reference to FIG. FIG. 6 is a schematic diagram showing the ejection amount of ink ejected from each nozzle 55 to each unit region U. As shown in FIG. In the present invention, an arbitrary area D on the paper P is partitioned by a plurality of unit areas U. The description of “small”, “medium”, and “large” in FIG. 6 means that a certain amount of ink, which is distinguished from small droplets, medium droplets, and large droplets, is ejected from each nozzle 55 to the unit region U. This means that the ink is not ejected to the region where neither medium nor large is described.

  For example, the above-described small droplets, medium droplets, and large droplets in which ink is not ejected are actually stored on the RAM 103 as numbers such as 0, 1, 2, and 3, respectively. Then, the CPU 101 discharges ink at the edge of the paper P by summing up the numbers in the unit areas U at the edge of the paper P and in the arbitrary area D, that is, summing up the numbers 0 to 3. To calculate.

  In this manner, the control unit 100 sums the ink ejection amounts for the respective unit areas U in the end portion of the paper P before the start of the recording process using the recording head 51, so that the end of the paper P to be described later is obtained. The ejection amount of the ink ejected to the part can be calculated in advance. The sum of the ink ejection amounts for each unit area U and the sum of the ink ejection amounts ejected to the edge of the paper P are stored in the RAM 103 by the CPU 101 and can be selectively read out. . Note that the calculation of the ink ejection amount for each unit area U may be performed by a configuration other than the CPU 101, such as the ASIC 106, or a printer driver provided in a personal computer connected to the multifunction device 1 or the like. You may go.

  The ASIC 106 generates a drive signal based on a command output from the CPU 101. Then, the ASIC 106 gives the generated drive signal to the drive circuit 107. The drive circuit 107 energizes the recording head 51 with the applied drive signal. Thereby, the piezoelectric element provided in each nozzle 55 of the recording head 51 is driven, and the ink existing in each nozzle 55 is ejected from each nozzle 55.

  Further, the ASIC 106 generates a phase excitation signal or the like for energizing the transport motor 108 based on a command from the CPU 101. Then, the ASIC 106 gives the generated phase excitation signal or the like to the drive circuit 109. The drive circuit 109 energizes the conveyance motor 108 with the applied phase excitation signal or the like. Thereby, rotation control of the conveyance motor 108 is performed. Then, the rotational force of the transport motor 108 is transmitted to the paper feed roller 22, the transport roller 41, and the paper discharge roller 61 via a known drive mechanism including a plurality of gears, drive shafts, and the like. In this way, the paper feed roller 22, the transport roller 41, and the paper discharge roller 61 are controlled by the control unit 100.

  Further, the ASIC 106 generates a phase excitation signal and the like for energizing the CR (carriage) motor 110 based on a command from the CPU 101. Then, the ASIC 106 gives the generated phase excitation signal or the like to the drive circuit 111 of the CR motor 110. The drive circuit 111 energizes the CR motor 110 with the applied phase excitation signal or the like. Thereby, rotation control of CR motor 110 is performed. Then, the rotational force of the CR motor 110 is transmitted to the carriage 53 via the belt drive mechanism 73. In this way, the reciprocation of the carriage 53 is controlled by the control unit 100.

  The ASIC 106 is connected to a rotary encoder 112 for the control unit 100 to detect the rotation amount of the transport roller 41 and a linear encoder 113 for detecting the movement amount of the carriage 53. The control unit 100 can accurately detect the position of the carriage 53 based on the signal from the linear encoder 113. In addition, the control unit 100 can accurately detect the positions of the recording head 51 and the media sensor 52 based on the detected position of the carriage 53.

  The ASIC 106 is connected to the light emitting unit 114 and the light receiving unit 115 of the media sensor 52. The light emitting unit 114 emits light according to a command from the CPU 101 or the ASIC 106. Then, an electrical signal corresponding to the intensity of the reflected light received by the light receiving unit 115 is generated. The CPU 101 or the ASIC 106 virtually detects the position where the input signal level is in the vicinity of the predetermined threshold C as the edge of the paper P by the electric signal generated from the media sensor 52.

  The ASIC 106 is connected to an operation panel 4 on which an operation instruction of the scanner unit 3 and the printer unit 2 is operated and instructed by a user.

<First Embodiment>
Conventionally, in order to increase the degree of freedom of installation of the multifunction machine 1, space saving of the multifunction machine 1 has been demanded. In particular, various methods have been taken to shorten the length of the multifunction device 1 in the depth direction (that is, the front-rear direction 200 in FIG. 1). Against this background, in the present invention, as shown in FIG. 5, the media sensor 52 is located on the downstream side of the nozzle 55 located on the most upstream side in the transport direction of the paper P among the plurality of nozzles 55. It arrange | positions at the carriage 53 so that it may be located.

  In the present invention, as shown in FIG. 3, the media sensor 52 is provided in the carriage 53 so as to be positioned on the return path side (that is, the left side in the left-right direction 300 in FIG. 3) with respect to the recording head 51. . Thereby, in the scanning of the carriage 53 in the forward direction (that is, from left to right in the left-right direction 300 in FIG. 3), the recording head 51 and the media sensor 52 are passed in this order above the left end PL or right end PR of the paper P. become. On the other hand, in the scanning of the carriage 53 in the backward direction (that is, from right to left in the left and right direction 300 in FIG. 3), the media sensor 52 and the recording head 51 are passed in this order above the right end PR or left end PL of the paper P. become.

  Here, since the media sensor 52 is a so-called light reflection type sensor that receives the reflected light of the light emitted from the light emitting unit 114 by the light receiving unit 115, the side of the paper P is scanned in the carriage 53 in the forward direction. The end position may not be detected accurately. This is a case where, for example, the side edge of the paper P is detected after ink is ejected to the side edge of the paper P in scanning in the forward direction of the carriage 53.

  More specifically, in the above case, ink is first ejected from the recording head toward the side edge of the paper P, and the ink lands on the paper P. Then, since the order of passing over the side edge of the paper P is the order of the recording head 51 and then the media sensor 52, the media sensor 52 irradiates light toward the spot where the ink has landed. Become. Then, for example, when the landed ink is black, the light receiving unit 115 receives reflected light from the black paper P. Since the platen 54 is black, the boundary between the black paper P and the side edges may be unclear. In particular, the case of so-called borderless recording in which ink is ejected to the side edge of the paper P corresponds to the above case. In other words, as described above, there is a possibility that the signal level from the media sensor 52 at the side edge of the paper P cannot exceed the predetermined threshold. In this case, the side edge of the paper P cannot be detected accurately.

  However, in the first embodiment, the control unit 100 executes the flowchart illustrated in FIG. 9, so that the media sensor 52 is used for both the forward path and the backward path of the carriage 53 in the main scanning direction. The side edge can be accurately detected.

  In the present invention, for the sake of convenience, a rectangular area having a horizontal width of 2r in the main scanning direction with the left end PL or right end PR as a midpoint and a vertical width of the paper P in the transport direction is defined as a region of the paper P. Defined as a side edge. In addition, since the area | region prescribed | regulated as this side edge part is determined by the magnitude | size of the opening 57 of the media sensor 52, the performance of the media sensor 52, etc., it cannot be overemphasized that it can change suitably.

  Next, recording processing of the first embodiment of the printer unit 2 having the above-described configuration will be described with reference to FIG. FIG. 9 is a flowchart showing a recording process executed by the control unit 100. The recording process shown in the flowchart of FIG. 9 is performed by the control unit 100 when the operation panel 4 is operated by the user and a command for recording an image on the paper P is input to the ASIC 106.

  When the recording process is executed by the control unit 100, the control unit 100 drives the transport motor 108 in step (hereinafter referred to as “S”) 1001. As a result, the paper feed roller 22 and the transport roller 41 are rotated, so that the paper P is transported and fed to the platen 54. In step S1001, the paper discharge start position in the transport direction is aligned with the position of the nozzle on the most downstream side in the transport direction among the plurality of nozzles formed in the recording head 51. For example, when printing with a margin of 3 mm from the downstream end in the transport direction of the paper P, the position 3 mm from the downstream end in the transport direction of the paper P is aligned with the position of the nozzle on the most downstream side in the transport direction.

  Thereafter, the control unit 100 drives the CR motor 110 to move the carriage 53, and causes the light emitting unit 114 of the media sensor 52 to emit light, thereby detecting the initial positions of both side edges of the paper P (S1002). Note that the moving distance of the carriage 53 is larger than the distance between both ends of the paper P. Note that unlike S1008 described later, no ink is ejected from the recording head 51 in S1002. In addition, instead of using the media sensor 52 in step S1002 to detect the initial positions of both ends of the paper P, the control unit 100 determines whether the paper P is in accordance with an instruction from the user via the operation panel 4, that is, the paper size input. The initial position of the side end may be determined in advance.

  Next, based on the signal from the rotary encoder 112, the control unit 100 determines whether or not the paper P has been conveyed by a predetermined amount after detecting the side edge of the paper P (S1003). If the control unit 100 determines that the paper P has been conveyed by a predetermined amount (S1003, YES), the process proceeds to S1004, and the control unit 100 performs the process of S1004. On the other hand, if the control unit 100 determines that the paper P is not conveyed by a predetermined amount, the process proceeds to S1007. At this time, the control unit 100 drives the recording head 51 while moving the carriage 53 by driving the CR motor 110, thereby discharging ink from the recording head 51 while the carriage moves in the main scanning direction. (S1007).

  Here, in S1007, the control unit 100 drives the CR motor 110 via the drive circuit 111 to move the carriage 53 in the main scanning direction. At this time, the control unit 100 drives the recording head 51 via the drive circuit 107 based on the image data stored in the RAM 103 and used for one scan of the carriage 53 and the output signal from the linear encoder 113. . In this manner, ink is ejected from the nozzles of the recording head onto the paper P, and an image or the like is recorded on the paper P. At this time, the control unit 100 does not detect the side edge of the paper P using the media sensor 52. Next, when the recording process is completed, the control unit 100 proceeds to S1011 and performs the process of S1011.

  In step S <b> 1004, the control unit 100 determines the movement direction of the carriage 53 in the scanning of the carriage 53 to be performed from now on based on the signal from the linear encoder 113 described above. When the movement direction of the carriage 53 is the forward direction (S1004: YES), the recording head 51 passes above the left end PL and right end PR of the paper P prior to the media sensor 52. In this case, the control unit 100 proceeds to S1005 and performs the process of S1005. On the other hand, when the moving direction of the carriage 53 is the return direction (S1004: NO), the media sensor 52 passes above the right end PR and the left end PL of the paper P prior to the recording head 51. In this case, the control unit 100 proceeds to S1008 described later, and performs the process of S1008.

  In step S <b> 1005, the control unit 100 determines that the ink discharge amount LL (or discharge amount LR) to the end of the left end PL (or right end PR) of the paper P is the scanning of the carriage in the forward direction to be performed. It is determined whether or not a predetermined threshold value X is exceeded. When the ink discharge amount LL (or discharge amount LR) to the end exceeds the threshold value X (S1005: YES), the control unit 100 proceeds to S1006 and performs the process of S1006. On the other hand, when the ink discharge amount LL (or discharge amount LR) to the end portion does not exceed the threshold value X (S1005: NO), the control unit 100 proceeds to S1008 described later and performs the process of S1008. . A plurality of threshold values X may be set such as X1, X2,..., Xn (X1 <X2 <... <Xn, Xn: arbitrary values).

  If the control unit 100 determines YES in S1005, the control unit 100 adjusts the light emission amount of the light emission unit 114 of the media sensor 52 based on the ink discharge amount LL (or the discharge amount LR) to the end portion ( S1006). More specifically, the control unit 100 inputs a current corresponding to the corrected current value I + α, which is corrected by adding a certain amount α to the current value I energized to the light emitting unit 114, thereby emitting light. The amount of light emitted from the unit 114 is adjusted. When a plurality of threshold values are provided as described above, the fixed amount α to be added corresponds to the threshold values X1, X2,..., Xn, and α1, α2,... Αn (α1 <α2 <... Αn, αn: A plurality of values may be set as in the case of arbitrary values. The light emission amount adjustment is not limited to this method. For example, the light emission amount adjustment is performed by a known method such as a method of changing a duty ratio of a pulse current to be supplied to the light emitting unit 114 of the media sensor 52 (so-called PWM method). May be. Next, the control unit 100 proceeds to S1008 and performs the process of S1008.

  In step S1008, the control unit 100 drives the CR motor 110 via the drive circuit 111 to move the carriage 53 in the main scanning direction. At this time, the control unit 100 drives the recording head 51 via the drive circuit 107 based on the image data stored in the RAM 103 and used for one scan of the carriage 53 and the output signal from the linear encoder 113. . In this manner, ink is ejected from the nozzles 55 of the recording head 51 onto the paper P, and an image or the like is recorded on the paper P. At this time, the control unit 100 uses the media sensor 52 to detect the left end PL and the right end PR of the paper P based on the output signal from the linear encoder 113. Next, the control unit 100 proceeds to S1009 and performs the process of S1009.

  Next, when the control unit 100 adjusts the light emission amount of the light emitting unit 114 of the media sensor 52 in S1009 (S1009: YES), the control unit 100 proceeds to S1010 and performs the process of S1010. On the other hand, when the control unit 100 does not adjust the light emission amount of the light emitting unit 114 (that is, NO in S1004 or NO in S1005, S1009: NO), the control unit 100 proceeds to S1011 and performs the process of S1011.

  Next, in step S <b> 1010, the control unit 100 returns the current value for energizing the light emitting unit 114 of the media sensor 52 to the current value I. Thereafter, the control unit 100 proceeds to S1011 and performs the process of S1011.

  Next, in S1011, when image data used in the next scan is stored in the RAM 103 (S1011: NO), the process proceeds to S1012 and the control unit 100 performs the process of S1012. On the other hand, if the image data is not stored in the RAM 103 (S1011: YES), the process proceeds to S1013, and the control unit 100 performs the process of S1013.

  In step S <b> 1012, the control unit 100 drives the transport motor 108 via the drive circuit 109 and transports the paper P by the transport roller 41. Thereafter, the process proceeds to S1003, and the control unit 100 performs the recording process by repeating the above-described control of S1003 to S1012.

  In S1013, when the image data of the next page is stored in the RAM 103 (S1013: YES), the process proceeds to S1001, and the control unit 100 performs the recording process by repeating the control of S1001 to S1013 described above. On the other hand, if the image data of the next page is not stored in the RAM 103 (S1013: NO), the recording process is terminated.

  Next, the waveform of the signal level from the media sensor 52 when the light emission amount of the media sensor 52 is not adjusted and when the light emission amount is adjusted will be described with reference to FIG. FIG. 10A shows the scanning of the platen 54, the rib 56, and the sheet P on which ink is ejected on the side edge and the forward direction of the carriage 53 (that is, the left-to-right direction in the left-right direction 300 in FIG. 3). It is the schematic diagram which showed the relationship. FIG. 10B is a graph showing the relationship between the signal level from the media sensor 52 and the number of encoder slits 204 when the light emission amount of the media sensor 52 is not adjusted. FIG. 10C is a graph showing the relationship between the signal level from the media sensor 52 and the number of encoder slits 204 when the light emission amount of the media sensor 52 is adjusted.

  As shown in FIGS. 10A and 10B, when the light emission amount of the media sensor 52 is not adjusted, the signal level from the media sensor 52 at the side edge of the paper P on which ink has been ejected is on the paper P. This is smaller than the area where no ink is ejected. For this reason, the signal level from the media sensor 52 at the side end cannot exceed the predetermined threshold C. In this case, since the control unit 100 erroneously detects the position of the side edge of the paper P, it adversely affects recording processing based on the erroneous detection result. On the other hand, as shown in FIGS. 10A and 10C, when the light emission amount of the media sensor 52 is adjusted, the signal level from the media sensor 52 increases as a whole, but the signal level is a certain constant value. It reaches saturation and becomes saturated. As a result, the signal level from the media sensor 52 at the side edge of the paper P on which the ink has been ejected and the signal level from the media sensor 52 in the area where the ink on the paper P has not been ejected are approximately approximate values. Will come to show. Therefore, the control unit 100 can accurately detect the side edge of the paper P because the signal level from the media sensor 52 at the side edge of the paper P on which ink has been ejected exceeds the predetermined threshold C. it can.

  As described above, in the first embodiment, the side edge of the paper P can be accurately detected using the media sensor 52 in both the forward path and the return path in the main scanning direction of the carriage 53.

<Second Embodiment>
When the light receiving unit 115 of the media sensor 52 receives the reflected light from the rib 56, the signal level of the reflected light from the rib 56 becomes higher than the signal level of the reflected light from the platen 54. The reflected light from the rib 56 and the platen 54 received by the light receiving unit 115 will be described with reference to FIG. FIG. 11A is a schematic diagram showing the relationship between the reflected light from the rib 56 and the light receiving unit 115, and FIG. 11B is a schematic diagram showing the relationship between the reflected light from the platen 54 and the light receiving unit 115. It is. As shown in FIGS. 11A and 11B, the reflected light from the rib 56 has a shorter light passage distance than the reflected light from the platen 54. Therefore, the influence of light attenuation is reduced, and the signal level of reflected light received by the light receiving unit 115 is increased. The distance from the light reflection point on the rib 56 to the light receiving unit 115 is shorter than the distance from the light reflection point on the platen 54 to the light receiving unit 115. Therefore, the influence of light dispersion is reduced. In particular, when unevenness is formed on the platen 54, the influence of light dispersion becomes large. Therefore, the signal level of the reflected light from the rib 56 is higher than the signal level of the reflected light from the platen 54.

  Here, when the control unit 100 executes the flowchart illustrated in FIG. 9 and adjusts the light emission amount of the media sensor 52, the signal level of the reflected light from the rib 56 and the side edge of the paper P on which ink has been ejected. Both of the reflected light signal levels may exceed a predetermined threshold. In this case, the control unit 100 may erroneously detect the position of the rib 56 in the main scanning direction as the position of the side edge of the paper P. In this case, the control unit 100 cannot accurately detect the side edge of the paper P.

  However, in the second embodiment, as shown in the flowchart of FIG. 12, when the control unit 100 executes the recording process, the rib 56 protruding from the platen 54 toward the carriage 53 is provided. The side edge of the paper P can be accurately detected using the media sensor 52.

  The recording process of the second embodiment of the printer unit 2 having the above-described configuration will be described with reference to FIG. FIG. 12 is a flowchart illustrating processing executed by the control unit 100 according to the second embodiment. Among the recording processes shown in the flowchart of FIG. 12, the same processes as those in the first embodiment (FIG. 9) are denoted by the same step numbers and the description thereof is omitted.

  In the recording process of the second embodiment, in step S1005, the control unit 100 discharges ink to the end of the left end PL (or right end PR) of the paper P in the carriage scan in the forward direction to be performed. It is determined whether LL (or the discharge amount LR) exceeds a predetermined threshold value X. When the ink discharge amount LL (or discharge amount LR) to the end exceeds the threshold value X, the control unit 100 proceeds to S1014 and performs the process of S1014. The process of S1014 will be described later with reference to FIGS. On the other hand, when the ink discharge amount LL (or discharge amount LR) to the end portion does not exceed the threshold value X, the control unit 100 proceeds to S1008 and performs the process of S1008.

  In step S1008, the control unit 100 drives the CR motor 110 via the drive circuit 111 to move the carriage 53 in the main scanning direction. At this time, the control unit 100 drives the recording head 51 via the drive circuit 107 based on the image data stored in the RAM 103 and used for one scan of the carriage 53 and the output signal from the linear encoder 113. . In this manner, ink is ejected from the nozzles 55 of the recording head 51 onto the paper P, and an image or the like is recorded on the paper P. At this time, the control unit 100 uses the media sensor 52 to detect the left end PL and the right end PR of the paper P based on the output signal from the linear encoder 113. Thereafter, the control unit 100 proceeds to S1011 and performs the process of S1011.

  Here, the side end portion of the paper P in the second embodiment will be described in more detail with reference to FIG. FIG. 13 is a schematic diagram illustrating the side edge of the paper P in detail. As shown in FIG. 13, for convenience of explanation, a position separated by a distance r from the left end PL of the paper P in the return path direction in the main scanning direction of the carriage 53 (that is, the left direction in the left-right direction 300 in FIG. 3) is a position PLl. A position separated by a distance r in the direction (that is, the right direction in the left-right direction 300 in FIG. 3) is defined as a position PLr. Similarly, a position that is separated from the right end PR of the paper P by a distance r in the return path direction in the main scanning direction of the carriage 53 is a position PR1, and a position that is separated by a distance r in the forward path direction is a position PRr. The distance r is the diameter r of the opening 57 of the housing that the media sensor 52 has.

  Next, the light emission amount adjustment process (S1014) of the media sensor 52 performed by the control unit 100 will be described with reference to FIG. FIG. 14 is a flowchart showing the light emission amount adjustment processing (S1014) of the media sensor 52 performed by the control unit 100.

  As shown in FIG. 14, in S1015, the control unit 100 drives the CR motor 110 via the drive circuit 111 to move the carriage 53 in the forward direction in the main scanning direction.

  Next, in S1016, the control unit 100 moves the carriage 53 in the forward direction until the media sensor 52 reaches the position PL1 (S1016: YES). When the media sensor 52 reaches above the position PLl (S1016: YES), the control unit 100 proceeds to S1017 and performs the process of S1017.

  In step S <b> 1017, the control unit 100 adjusts the light emission amount of the light emitting unit 114 of the media sensor 52 based on the ink discharge amount LL (or the discharge amount LR) to the end portion. More specifically, the control unit 100 inputs a current corresponding to the corrected current value I + α, which is corrected by adding a certain amount α to the current value I energized to the light emitting unit 114, thereby emitting light. The amount of light emitted from the unit 114 is adjusted. When the light emission amount adjustment of the light emitting unit 114 is completed, the control unit 100 proceeds to S1018 and performs the process of S1018.

  In step S1018, the control unit 100 drives the CR motor 110 via the drive circuit 111, and moves the carriage 53 in the forward direction in the main scanning direction. At this time, the control unit 100 drives the recording head 51 via the driving circuit 107 based on the image data stored in the RAM 103 and used for one scan of the carriage 53 and the output signal from the linear encoder 113. . In this manner, ink is ejected from the nozzles 55 of the recording head 51 onto the paper P, and an image or the like is recorded on the paper P. At this time, the control unit 100 uses the media sensor 52 to detect the left end PL and the right end PR of the paper P based on the output signal from the linear encoder 113. Thereafter, the control unit 100 proceeds to S1019 and performs the process of S1019.

  Next, in S1019, the control unit 100 determines whether or not the media sensor 52 has reached the position PRr. When the media sensor 52 reaches above the position PRr (S1019: YES), the control unit 100 ends the process of S1014 and proceeds to S1011. On the other hand, when the media sensor 52 has not reached the position PRr (S1019: NO), the control unit 100 returns to S1018 and repeats S1018 and S1019.

  Next, the waveform of the signal level from the media sensor 52 when the control unit 100 executes the flowchart shown in FIG. 9 and when the control unit 100 executes the flowchart shown in FIG. 12 will be described with reference to FIG. To do. FIG. 15A shows the scanning of the platen 54, the rib 56, and the sheet P on which ink is ejected on the side end, and the forward direction of the carriage 53 (that is, the left-right direction 300 in FIG. 3 from left to right). It is the schematic diagram which showed the relationship. FIG. 15B is a graph showing the relationship between the signal level from the media sensor 52 and the number of encoder slits 204 when the control unit 100 executes the flowchart shown in FIG. FIG. 15C is a graph showing the relationship between the signal level from the media sensor 52 and the number of encoder slits 204 when the control unit 100 executes the flowchart shown in FIG.

  As illustrated in FIGS. 15A and 15B, when the control unit 100 executes the flowchart illustrated in FIG. 9, the signal level from the media sensor 52 in the rib 56 may exceed a predetermined threshold C. In this case, since the control unit 100 erroneously detects the position of the rib 56 as the position of the side edge of the paper P, it adversely affects recording based on the erroneous detection result. On the other hand, as shown in FIGS. 15A and 15C, when the control unit 100 executes the flowchart shown in FIG. 12, the signal level from the media sensor 52 in the rib 56 does not increase. On the other hand, the signal level from the media sensor 52 at the side edge portion of the paper P on which the ink is ejected and the signal level from the media sensor 52 in the area where the ink on the paper P is not ejected are approximately approximate values. It becomes like this. Therefore, the control unit 100 can accurately detect the side edge of the paper P because the signal level from the media sensor 52 at the side edge of the paper P on which ink has been ejected exceeds the predetermined threshold C. it can.

  In the second embodiment, the control unit 100 can accurately detect the side edge of the paper P by using the media sensor 52 and can save the power consumed by the media sensor 52. Therefore, power saving and long life of the media sensor 52 can be realized. Further, as described above, the media sensor 52 is used even when the rib 56 protruding toward the carriage 53 is provided on the platen in the region other than the outer side end portion of the side end portion of the paper P. Thus, the side edge of the paper P can be accurately detected.

  In S1014, the control unit 100 adjusts the light emission amount of the media sensor 52 in the section from the position PL1 to the position PRr to detect the side edge of the paper P, but in the section from the position PLr to the position PR1. The light emission amount of the media sensor 52 may be returned to the standard (that is, the standard current value I). Further, the control unit 100 may turn off the light emitting unit 114 of the media sensor 52 except for the sections of the positions PLl to PLr and the position PR1 to the position PRr.

  In the embodiment as described above, the control unit 100 can accurately detect the side edge of the paper P using the media sensor 52 and can further save the power consumed by the media sensor 52. Therefore, further power saving and long life of the media sensor 52 can be realized.

  Note that the threshold value of the ink ejection amount in the present invention is determined by the light reflectance of the surface of the paper P. For example, in the case where there are three types of paper P, that is, plain paper, inkjet paper, and glossy paper, a description will be given below. The light reflectance on the plain paper surface is ρf, the light reflectance ρi on the inkjet paper surface, and the threshold on the glossy paper surface is ρk. At this time, the relationship of ρf <ρi <ρk is established. Therefore, the signal level from the media sensor 52 at the location where the ink on the paper P is ejected increases in the order of plain paper, inkjet paper, and glossy paper. That is, if the threshold value for plain paper is Xf, the threshold value for inkjet paper is Xi, and the threshold value for glossy paper is Xk, the relationship Xf ≦ Xi ≦ Xk is established. Therefore, the threshold value of the ink ejection amount in the present invention is determined by the light reflectance of the surface of the paper P. The control unit 100 may determine the paper type of the paper P based on an operation instruction from an external terminal such as a personal computer connected to the multifunction device 1. Further, the control unit 100 may determine the paper type of the paper P based on an instruction from the user via the operation panel 4, that is, input of the paper type. Further, the control unit 100 drives the CR motor 110 via the drive circuit 111 and selects the paper type of the paper P based on the signal level of the signal from the media sensor 52 obtained by moving the carriage 53 in the main scanning direction. You may judge.

  The threshold C of the signal level from the media sensor 52 in the present invention is a value corresponding to about 60% of the saturation value of the signal level from the media sensor 52. In the present invention, 50% to 70% of the saturation value of the signal level from the media sensor 52 is defined as a value of about 60%.

In the present invention, the case where the control unit 100 adjusts the signal level from the media sensor 52 by adjusting the light emission amount of the media sensor 52 has been described. For example, the signal level from the media sensor 52 (that is, the signal level) May be adjusted so that the signal level from the side edge of the paper P on which the ink has been ejected exceeds a predetermined threshold value C.
In the present invention, the case where the paper P is used has been described for convenience of explanation. However, a recording medium other than the paper, such as a CD, may be used.

Claims (8)

Conveying means for conveying the recording medium in the conveying direction;
A plurality of nozzles, and a recording head that records an image by discharging ink from the plurality of nozzles onto the recording medium;
Optical sensor for detecting the position of the side end in the main scanning direction, which is disposed on the downstream side in the transport direction from the nozzle formed on the most upstream side in the transport direction among the plurality of nozzles, and irradiates light toward the recording medium When,
A carriage that includes the recording head and the optical sensor and moves in a main scanning direction orthogonal to the transport direction;
Side edge detecting means for detecting the position of the side edge of the recording medium based on a signal level emitted from the optical sensor;
Calculating means for calculating an ejection amount of ink ejected to the side end portion;
When the ejection amount calculated by the calculation means exceeds a threshold value and when the optical sensor is at least located on the side edge of the recording medium, the signal level emitted from the optical sensor exceeds a predetermined amount. Control means to adjust;
A recording apparatus comprising:   The control means is emitted from the optical sensor when the optical sensor reaches a position outside the recording medium of the side edge of the recording medium and farthest from the side edge of the recording medium. The recording apparatus according to claim 1, wherein a signal level is adjusted. The optical sensor has an opening of the predetermined distance, and emits light toward the recording medium through the opening, receives light reflected by the recording medium,
The control means adjusts a signal level emitted from the optical sensor when the optical sensor reaches a position outside the recording medium and at a predetermined distance from the side edge of the recording medium. The recording apparatus according to claim 2.   The recording apparatus according to claim 2, wherein the control unit turns off the optical sensor when the optical sensor is located at a position other than the end of the recording medium.   The recording apparatus according to claim 1, wherein the control unit adjusts the signal level by increasing a light emission amount of the optical sensor from a predetermined reference value.   The recording apparatus according to claim 5, wherein the predetermined reference value is the light emission amount when the signal level is not adjusted by the control unit.   The recording apparatus according to claim 1, wherein the threshold value is determined by a light reflectance of the recording medium. The recording apparatus according to claim 1, wherein the predetermined amount is a value corresponding to about 60% of a saturation value of a signal level emitted from the optical sensor.

Images