JP2009045912A - Attachment structure of linear sensor and printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an attachment structure of linear sensor and a printer, wherein the attachment position of the linear sensor is optimized. <P>SOLUTION: The attachment structure of the linear sensor 52 in the printer 10 enables a carriage 21, to which a print head 28 for jetting ink droplets is attached, to slide along a carriage shaft 26. In the side close to the print head 28 rather than to the carriage shaft 26 in the discharge direction of the ink droplets, a sensor housing part 53 integrally formed with the carriage 21 is provided. The linear sensor 52 is attached to the sensor housing unit 53. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a linear sensor mounting structure and a printer.

  In an ink jet printer, a linear encoder is used to detect the position of the carriage in the main scanning direction. The linear encoder includes a linear scale and a linear sensor, and the linear sensor is an optical sensor including a light emitting unit and a light receiving unit. Here, the linear sensor is mounted on a substrate, and the substrate is attached and fixed to the carriage by screws. This linear sensor is attached above the carriage shaft (see Patent Document 1).

JP 2007-105891 A (see FIG. 3 etc.)

  By the way, the substrate on which the linear sensor is mounted is a separate body from the carriage, and is mounted and fixed via screws. For this reason, there is a problem in that the mounting of the substrates varies and it is difficult to reduce the size. Also, as shown in the above-mentioned Patent Document 1, the mounting position of the substrate is on the upper side of the carriage shaft and is relatively far from the print head, so the detection by the linear sensor does not match the behavior of the print head. There is also a problem. Therefore, it is desired to optimize the mounting position of the linear sensor.

  The present invention has been made based on the above circumstances, and an object of the present invention is to provide a linear sensor mounting structure and a printer in which the mounting position of the linear sensor is optimized.

  In order to solve the above-described problems, the present invention provides an attachment of a linear sensor for detecting the position of a carriage when the carriage on which a print head for ejecting ink droplets is attached is slid along a sliding axis. A sensor housing unit that is integrally formed with the carriage is provided on the print head side of the sliding axis in the ink droplet ejection direction, and a linear sensor is attached to the sensor housing unit. Is.

  In such a configuration, a sensor storage unit integrally formed with the carriage is provided, and a linear sensor is attached to the sensor storage unit. Compared with the case of attaching to the mounting, it is possible to suppress the mounting variation, and it is possible to improve the mounting accuracy. In addition, since the sensor housing is provided on the print head side with respect to the sliding shaft, it is compared with the conventional configuration in which the linear sensor mounting part is on the opposite side of the printing head across the sliding shaft. Thus, the detection by the linear sensor and the behavior of the print head are not in opposite phases, and it is possible to make the behavior substantially coincide.

  According to another invention, in addition to the above-described invention, the sensor storage portion is provided on the downstream side of the sliding shaft and the upstream side of the print head in the transport direction of the print medium on which the ink droplets are ejected. It is what.

  When configured in this manner, the detection by the linear sensor and the behavior of the print head are not in opposite phases even in the conveyance direction of the print medium, and the behavior can be substantially matched. As a result, the behavior of the print head during the carriage scan can be detected even better.

  Further, according to another invention, in addition to the above-described invention, the linear sensor further includes a light-emitting unit that emits light, and is disposed so as to face the light-emitting unit with a space, and receives light emitted from the light-emitting unit. A linear scale having a light-transmitting portion that transmits light and a light-blocking portion that blocks light is disposed in the space, and the sensor storage portion is positioned upstream of the carriage. The light receiving portion is attached to the carriage side of the sensor storage portion.

  In such a configuration, since the light receiving portion is attached to the carriage side, the portion that receives the light and actually outputs the detection signal is in the state closest to the print head. Therefore, the detection at the light receiving unit of the linear sensor becomes closer to the behavior of the print head, and the behavior of the print head during scanning of the carriage can be detected even better.

  According to another invention, in addition to the above-described inventions, the sensor storage portion opens toward the print head in the ink droplet ejection direction.

  When configured in this manner, the linear scale can be projected from the portion opened to the print head side, and the linear sensor can be inserted from the opening.

  Furthermore, in another invention, in addition to the above-described invention, the sensor storage portion opens toward the sliding shaft side in the ink droplet ejection direction.

  In such a configuration, the ink head is opened in the direction opposite to the print head side, and ink droplets ejected from the print head can be prevented from entering from the opening.

  According to another invention, in addition to the above-described inventions, the sensor storage portion is provided at a substantially central portion of the carriage in the sliding direction along the sliding axis of the carriage.

  In the case of such a configuration, it is possible to suppress unstable detection as compared with the case where the sensor storage portion is provided at the end portion in the sliding direction of the carriage.

  Furthermore, another invention comprises a linear sensor mounting structure according to each of the above-described inventions in a printer.

  In such a configuration, a sensor storage unit integrally formed with the carriage is provided, and a linear sensor is attached to the sensor storage unit. Compared with the case of attaching to the mounting, it is possible to suppress the mounting variation, and it is possible to improve the mounting accuracy. In addition, since the sensor housing is provided on the print head side with respect to the sliding shaft, it is compared with the conventional configuration in which the linear sensor mounting part is on the opposite side of the printing head across the sliding shaft. Thus, the detection by the linear sensor and the behavior of the print head are not in opposite phases, and it is possible to make the behavior substantially coincide.

  Hereinafter, a linear sensor mounting structure and a printer 10 according to an embodiment of the present invention will be described with reference to FIGS. Note that the printer 10 of the present embodiment is an ink jet printer, but the ink jet printer may be an apparatus that employs any ejection method as long as the apparatus is capable of printing by ejecting ink.

  In the following description, the lower side refers to the side where the printer 10 is installed, and the upper side refers to the side away from the installed side. Further, the side on which the print medium P is supplied is described as a feeding side (rear end side), and the side on which the print medium P is discharged is described as a paper discharge side (front side). A direction in which a carriage 21 described later moves is a main scanning direction, and a direction perpendicular to the main scanning direction and a direction in which the print target P is conveyed is a sub-scanning direction.

<Schematic Configuration of Printer 10>
As shown in FIG. 1, the printer 10 includes a casing unit (not shown), a carriage mechanism 20, a paper transport mechanism 30, a linear encoder 50, a control unit 100, and the like as main components.

  Among these, the carriage mechanism 20 includes a carriage 21, a carriage motor (CR motor 22), a belt 23, a gear pulley 24, a driven pulley 25, and a carriage shaft 26 (corresponding to a sliding shaft). Among these, the carriage 21 can mount ink cartridges 27 of the respective colors. As shown in FIGS. 1 and 2, a print head 28 capable of ejecting ink droplets is provided on the lower surface of the carriage 21. The belt 23 is an endless belt, and a part of the belt 23 is fixed to the back surface 21 a of the carriage 21. The belt 23 is stretched by a gear pulley 24 and a driven pulley 25.

  The above-described print head 28 is provided with a nozzle row (not shown) associated with each ink, and a piezo element (not shown) is arranged in the nozzle constituting the nozzle row. By operating the piezo element, it is possible to eject ink droplets from the nozzles at the end of the ink passage. The print head 28 is not limited to a piezo drive system using a piezo element. For example, a heater system that heats ink with a heater and uses the force of generated bubbles, a magnetostriction system that uses a magnetostrictive element, and a mist that is controlled by an electric field. A mist method or the like may be employed. The ink filled in the cartridge 27 may be mounted with any kind of ink such as dye-based ink / pigment-based ink.

  As shown in FIG. 1 and the like, the paper transport mechanism 30 includes a PF motor 31 for transporting the print medium P and the like, and a paper feed roller 32 corresponding to paper feed of plain paper or the like. Further, a PF roller pair 33 for conveying / clamping the print medium P is provided on the paper discharge side with respect to the paper supply roller 32. The PF roller pair 33 includes a PF driving roller 33a that is rotated by driving the PF motor 31, and a PF driven roller 33b that is biased by the PF driving roller 33a by receiving a biasing force by a spring (not shown).

  On the paper discharge side of the PF roller pair 33, the platen 34 and the above-described print head 28 are arranged so as to face each other vertically. The platen 34 corresponds to the placement unit, and supports the print medium P conveyed below the print head 28 by the PF roller pair 33 from below. Further, on the paper discharge side with respect to the platen 34, a paper discharge roller pair 35 similar to the PF roller pair 33 described above is provided. Of this pair of paper discharge rollers 35, the drive power from the PF motor 31 is transmitted to the paper discharge drive roller 35a together with the PF drive roller 33a.

  As shown in FIG. 1, the rotary encoder 40 includes a disk-shaped scale 41 and a rotary sensor 42. Among these, the disc scale 41 has the same configuration as the linear scale 51 described later except that it is circular, and the description thereof is omitted. The disc scale 41 is rotated by the PF motor 31. The rotary sensor 42 has the same configuration as a linear sensor 52 described later, and a description thereof will be omitted. Further, the printer 10 includes a control unit 100, and outputs (detection signals) from the rotary sensor 42 and the linear sensor 52 are input to the control unit 100. A computer 120 can be connected to the printer 10.

<Regarding the mounting structure of the linear sensor>
Next, the configuration of the linear encoder and the mounting structure of the linear sensor will be described with reference to FIGS. As shown in FIGS. 2 and 3, the linear encoder 50 includes a linear scale 51 and a linear sensor 52. Among these, the linear scale 51 has a light-transmitting part (not shown) that transmits light and a light-shielding part (not shown) that blocks light transmission. They are alternately arranged at regular intervals.

  The linear sensor 52 is an optical sensor that includes a light emitting unit 52a and a light receiving unit 52b. Among these, the light emitting unit 52a includes a light emitting element such as a light emitting diode. Further, a collimator lens (not shown) is attached to the light emitting unit 52a, and the light emitted from the light emitting unit 52a is arranged so as to go to the light receiving unit 52b. In addition, the light receiving unit 52b includes a light receiving element such as a phototransistor, a photodiode, a photo IC, or the like, and the two light receiving element columns are arranged to be shifted from each other by a quarter pitch. Yes. Accordingly, the phase difference between the rows of the light receiving elements becomes 90 degrees, and when the light emitted from the light emitting unit 52a is received, it is possible to output a pulse signal whose phase is shifted by 90 degrees.

  Further, both the light emitting unit 52a and the light receiving unit 52b include lead wires 52a1 and 52b1. The lead wires 52a1 and 52b1 are electrically connected to a substrate (not shown) provided outside the sensor storage portion 53. It can be attached to various parts such as an upper surface of a rear protrusion 531 described later, a rear surface 21a of the carriage 21, and a part on the inner side of the carriage 21 that can prevent wetting by ink droplets.

  As shown in FIG. 3, on the back surface 21 a side of the carriage 21, a sensor housing portion 53 that is a main part of the mounting structure of the linear sensor 52 is provided. The sensor storage portion 53 is a portion for attaching the light emitting portion 52a and the light receiving portion 52b as described above. The sensor storage portion 53 is a portion that is formed integrally with the carriage 21 and protrudes from the carriage 21 toward the back surface 21a. As shown in FIG. 3, the sensor storage portion 53 is provided so that its side surface has a bowl shape. In addition, the sensor storage portion 53 is provided with an opening 530 toward the upper side, and the linear scale 51 described above protrudes upward from the opening 530.

  The sensor storage unit 53 includes a back protrusion 531, an upward extension 532, and a tongue piece 533. Among these, the rear surface protruding portion 531 is a portion that protrudes from the rear surface 21 a of the carriage 21 toward the upstream side (paper feeding side). The projecting length of the rear surface projecting portion 531 is set such that a predetermined gap is provided between the light emitting portion 52 a and the linear scale 51 and between the light receiving portion 52 b and the linear scale 51. And even if the linear scale 51 vibrates somewhat, the linear scale 51 is provided to such an extent that it does not contact the light emission part 52a or the light-receiving part 52b.

  Further, the upward extending portion 532 is a portion extending upward from the protruding end of the back surface protruding portion 531. The protruding length of the upward extending portion 532 is such that when the light emitting portion 52 a and the light receiving portion 52 b are attached to the sensor storage portion 53, the light emitting portion 52 a and the light receiving portion 52 b are interposed between the upper surface of the rear protruding portion 531. The predetermined gap is present. Further, the tongue piece portion 533 is a portion protruding from the upper end side of the upper extending portion 532 toward the back surface 21 a of the carriage 21. As shown in FIG. 3, the tongue piece 533 is sufficiently shorter than the protruding length of the rear protrusion 531. In the present embodiment, the tongue piece 533 is long enough to reach approximately half of the light emitting portion 52a. It has a size.

  In FIG. 3, the light receiving portion 52 b is attached to the back surface 21 a of the carriage 21 and the portion surrounded by the sensor storage portion 53. However, as shown in FIG. 4, a protruding portion 534 protruding from the back surface 21 a may be provided, and the light receiving portion 52 b may be attached to the protruding portion 534.

  As shown in FIG. 2, the mounting positions of the light emitting unit 52 a and the light receiving unit 52 b in the sensor storage unit 53 are set on the print head 28 side (lower side) with respect to the carriage shaft 26 in the ink droplet ejection direction (vertical direction). It is provided so that it may be located in. Further, the sensor storage portion 53 is arranged so that the linear scale 51 can be read at a portion downstream of the carriage shaft 26 and upstream of the print head 28. That is, the attachment portion of the light receiving portion 52b is located on the downstream side of the axis A (see FIG. 5) of the carriage shaft 26.

  Further, the sensor storage portion 53 is attached to a portion that is approximately the center of the carriage 21 in the main scanning direction. Here, in the present embodiment, the print head 28 is also attached to a portion that is substantially at the center of the carriage 21 in the main scanning direction. For this reason, the detection by the linear sensor 52 also accurately reflects the behavior of the print head 28 in the main scanning direction.

<Print head behavior and detection by linear sensor>
FIG. 5 shows the relationship between the behavior of the print head 28 and the detection by the linear sensor 52. FIG. 5 is a schematic diagram in the side surface direction of the print head 28 and the like. As shown in FIG. 5, the print head 28 moves in the rotation direction about the axis A of the carriage shaft 26 as a fulcrum (see the portion indicated by the alternate long and short dash line). At that time, in the present invention, since the light receiving part 52b of the linear sensor 52 is present at the part indicated by the solid line in FIG. The detection at is proportional to the print head 28.

  On the other hand, in the conventional configuration, the light receiving portion 52b of the linear sensor 52 is attached to a portion indicated by a broken line in FIG. For this reason, the behavior of the print head 28 is opposite in phase to the detection at the light receiving unit 52b, and the detection at the light receiving unit 52b does not correctly reflect the behavior of the print head 28.

  The arrangement relationship of the carriage shaft 26, the light receiving portion 52b, and the print head 28 in FIG. 5 is the same not only in the side surface direction of the print head 28 and the like, but also in the front direction and the plane direction viewed from above. Yes. Therefore, in the present embodiment, the behavior of the print head 28 is in the same direction as the detection by the light receiving unit 52b, and the detection by the light receiving unit 52b has a proportional relationship with the print head 28.

  Further, since the conventional configuration does not have the positional relationship of the carriage shaft 26, the light receiving portion 52b, and the print head 28 in the present embodiment, the print head 28 vibrates due to, for example, sudden acceleration or sudden deceleration of the carriage 21. Even if the movement of the print head 28 is absorbed by the backlash of the attachment portion of the carriage 21 with respect to the carriage shaft 26, or the print head 28 is not moving so much, the light receiving unit. In 52b, it is detected as if there is a movement. However, in the present embodiment, since the carriage shaft 26, the light receiving unit 52b, and the print head 28 are arranged as described above, the behavior of the print head 28 is always in the same direction as the detection by the light receiving unit 52b. It will be good.

<Effects of the present invention>
According to the mounting structure of the linear sensor 52 configured as described above and the printer 10, the sensor storage portion 53 integrally formed with the carriage 21 is provided, and the linear sensor 52 is attached to the sensor storage portion 53. In addition, as compared with the case where the substrate on which the linear sensor 52 is mounted is attached to the carriage 21 via screws, it is possible to suppress the attachment variation and to improve the attachment accuracy.

  Further, since the sensor storage portion 53 is provided on the print head 28 side with respect to the carriage shaft 26, the attachment portion of the linear sensor 52 exists on the opposite side of the print head 28 with the carriage shaft 26 interposed therebetween as in the conventional case. Compared to the configuration, the detection in the linear sensor 52 and the behavior with the print head 28 are not in opposite phases, and the behavior can be made to substantially coincide.

  The sensor storage portion 53 is provided downstream of the carriage shaft 26 and upstream of the print head 28 in the sub-scanning direction. For this reason, even in the sub-scanning direction, the detection by the linear sensor 52 and the behavior with the print head 28 do not become in opposite phases, and the behavior can be substantially matched. Therefore, the behavior of the print head 28 during the scanning of the carriage 21 can be detected even better.

  Further, a light receiving portion 52 b is attached to the carriage 21 side of the sensor storage portion 53. Therefore, the light receiving unit 52b that receives light and actually outputs a detection signal is in a state closest to the print head 28. Therefore, the detection in the light receiving unit 52b becomes closer to the behavior of the print head 28, and the behavior of the print head 28 during the scanning of the carriage 21 can be detected better.

  In the present embodiment, the opening 530 is configured to open upward. For this reason, the opening 530 is opened in a direction opposite to the print head 28, and it is possible to prevent ink droplets (mist) ejected from the print head 28 from entering the opening.

  Further, the sensor storage portion 53 is provided at a substantially central portion of the carriage 21 in the main scanning direction. Therefore, it is possible to suppress unstable detection as compared with the case where the sensor storage unit 53 is provided at the end of the carriage 21 in the main scanning direction.

<Modification>
Although one embodiment of the present invention has been described above, the present invention can be variously modified. This will be described below.

  In the above-described embodiment, the opening 530 opens upward. However, the opening may be configured to open not only upward but also downward. When the opening portion opens downward, the linear scale 51 can be easily projected from the opening portion, and the linear sensor 52 can be easily inserted from the opening portion. .

  Further, in the above-described embodiment, when it is necessary to improve only the mounting accuracy of the linear sensor 52, the mounting portion of the linear sensor 52 does not need to be the sensor storage portion 53, and is the same as the conventional one. It may be a part. In addition, a configuration in which the sensor storage portion 53 exists in a portion other than between the carriage shaft 26 and the print head 28 in any portion in the main scanning direction, the sub scanning direction, and the vertical direction may be employed.

  Further, in the above-described embodiment, the sensor storage portion 53 protrudes from the rear surface 21a of the carriage 21. However, in addition to this, for example, a linear scale similar to a hole portion for allowing the carriage shaft 26 to pass through the carriage 21 is used. A hole for inserting 51 may be provided, and the light emitting unit and the light receiving unit may be arranged inside the carriage 21 with the hole interposed therebetween.

  In addition, the sensor storage unit 53 in the present embodiment is not limited to the case where it is provided in the carriage 21 of the printer 10. For example, a similar configuration may be employed in a scanner head or the like.

1 is a schematic diagram illustrating a configuration of a printer according to an embodiment of the present invention. FIG. 2 is a schematic side view illustrating the configuration of the printer of FIG. 1. FIG. 2 is an enlarged cross-sectional view illustrating the vicinity of a sensor storage unit in the printer of FIG. 1. It is sectional drawing which shows the modification of the sensor accommodating part of FIG. It is a schematic diagram which shows the positional relationship of a linear sensor and a print head.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Printer, 20 ... Carriage mechanism, 21 ... Carriage, 26 ... Carriage shaft (corresponding to a sliding axis), 28 ... Print head, 30 ... Paper conveyance mechanism, 50 ... Linear encoder, 51 ... Linear scale, 52 ... Linear sensor 52a ... light emitting part, 52b ... light receiving part, 53 ... sensor housing part, 100 ... control part, 530 ... opening part, 531 ... back projection part, 532 ... upward extension part, 533 ... tongue piece part, 534 ... projection part

Claims (7)

A linear sensor mounting structure for detecting the position of the carriage when the carriage on which the print head for ejecting ink droplets is mounted is slid along the sliding axis.
In the ink droplet ejection direction, on the print head side with respect to the sliding shaft, a sensor housing unit that is integrally formed with the carriage is provided,
The linear sensor is attached to the sensor storage unit.
A mounting structure for a linear sensor.   2. The sensor storage unit according to claim 1, wherein the sensor storage unit is provided downstream of the sliding shaft and upstream of the print head in a transport direction of the print medium on which the ink droplets are ejected. Linear sensor mounting structure. The linear sensor includes a light emitting unit that emits light, and a light receiving unit that is disposed to face the light emitting unit with a space and receives light emitted from the light emitting unit.
In the space, a linear scale having a light-transmitting part that transmits light and a light-shielding part that blocks light is arranged,
The sensor storage portion protrudes toward the upstream side from the rear surface located on the upstream side of the carriage,
3. The linear sensor mounting structure according to claim 2, wherein the light receiving unit is mounted on the carriage side of the sensor storage unit.   4. The linear sensor mounting structure according to claim 1, wherein the sensor storage portion opens toward the print head in the ink droplet ejection direction. 5.   4. The linear sensor mounting structure according to claim 1, wherein the sensor storage portion is opened toward the sliding shaft in the ink droplet ejection direction. 5.   6. The linear device according to claim 1, wherein the sensor storage portion is provided at a substantially central portion of the carriage in a sliding direction along the sliding axis of the carriage. Sensor mounting structure.   A printer comprising the linear sensor mounting structure according to claim 1.

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