JP5636935B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus.

  2. Description of the Related Art Conventionally, there is known an ink jet image forming apparatus that forms an image on a recording medium by reciprocating a carriage mounted with a recording head in the main scanning direction and ejecting ink by the recording head.

  In this type of image forming apparatus, as an encoder for detecting the position of the carriage, a linear type or rotary type encoder scale on which a predetermined pattern is formed, and an encoder sensor for detecting the predetermined pattern formed on the encoder scale are provided. I have.

  As the encoder scale, there are known an encoder scale in which a light / dark pattern is formed at a predetermined pitch and a slit hole formed in a predetermined pitch.

  However, in an image forming apparatus equipped with an encoder scale on which a light and dark pattern is formed, it is possible to increase the resolution of the encoder by increasing the resolution of the light and dark pattern in terms of processing technology. There are inconveniences such as deterioration of the detection performance of the light / dark pattern.

  On the other hand, in an image forming apparatus equipped with an encoder scale in which slit holes are formed, there is no possibility that the detection performance of the slit holes will be deteriorated due to the adhesion of ink, but the pitch of the slit holes can be increased in terms of processing technology. Since it is difficult, there is a disadvantage that the resolution of the encoder cannot be increased.

  Further, in recent image forming apparatuses, ink used for high precision is reduced in size, so that minute ink (hereinafter simply referred to as “ink mist”) that flies inside the housing without landing on the recording medium. ") Is easily attached to the encoder scale, and the encoder scale is more easily contaminated than the conventional one.

  As a conventional technique for solving such a problem, for example, an image forming apparatus (see Patent Document 1) having an encoder sensor and a cover or suction member that covers a part of the encoder scale adjacent to the encoder sensor, or an encoder scale is used. An image forming apparatus having a cleaning means for cleaning (see Patent Document 2) is known.

JP 2001-113772 A JP 2002-361901 A

  However, in the image forming apparatus of Patent Document 1, although the cover and the suction member can reduce the adhesion of ink mist to the encoder sensor to some extent, since the cover does not cover the entire encoder scale, the encoder scale and the encoder sensor There is a disadvantage that the ink mist cannot be completely prevented from adhering to the ink.

  However, in the image forming apparatus disclosed in Patent Document 2, ink mist adhering to the encoder scale can be accurately removed at an early stage where the urethane resin of the cleaning unit is not dirty, but the urethane resin becomes dirty as it is used. Therefore, there is a disadvantage that the effect of removing the ink mist stains is likely to decrease with time.

  Further, in the image forming apparatus disclosed in Patent Document 2, when the ink mist adhering to the encoder scale cannot be completely wiped off by the urethane resin of the cleaning means, the encoder scale is undesirably enlarged. is there.

  That is, in the conventional image forming apparatus, there is a problem that the movement control of the carriage with high accuracy cannot be performed due to the inconvenience described above, and the quality of image formation is low.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that can control the movement of a carriage with high accuracy without being affected by ink.

In order to solve the above-described problems and achieve the object, an image forming apparatus according to the present invention is rotated in accordance with the movement of the carriage and mounted on a concentric circle with a carriage on which a head for ejecting ink is mounted. A scale on which the pattern is formed, a sensor for detecting the predetermined pattern of the scale, and the carriage, the scale and the sensor are accommodated, and the scale and the sensor are accommodated in the head. A housing portion for preventing the ink ejected from adhering to adhere ; a bearing member fitted in a hole formed in the housing portion; a shaft member pivotally supported by the bearing member; and a power to the shaft member. And a rack having teeth engaged with the gear and arranged along a moving direction of the carriage, and the scale includes the carriage. By the gear and the shaft member is driven with the movement of Tsu di, it is pivoted sealed the receptacle by the bearing member and the shaft member.

  According to the present invention, it is possible to provide an image forming apparatus that can perform high-precision carriage movement control without being affected by ink and that has high image forming quality.

FIG. 1 is a front view illustrating a schematic configuration in a housing of the image forming apparatus according to the first embodiment. FIG. 2 is an enlarged cross-sectional view of the carriage when viewed in the direction of the arrow from the line XX shown in FIG. FIG. 3 is a plan view when viewed in the direction of arrow B shown in FIG. 4 is a cross-sectional view when viewed in the direction of the arrow from the YY line shown in FIG. FIG. 5 is a block diagram for explaining a hardware configuration of the image forming apparatus. FIG. 6 is a flowchart for explaining the overall processing flow in the image forming apparatus.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  In the following, an image forming apparatus according to the present embodiment will be described in the case of an ink jet printer that forms an image on a recording medium by ejecting ink while a carriage mounted with a head scans and moves on the recording medium. .

  FIG. 1 is a front view showing a schematic configuration inside the housing of the image forming apparatus according to the first embodiment, and FIG. 2 is a carriage when viewed in the arrow direction from the line XX shown in FIG. FIG. 3 is a plan view when viewed in the direction of arrow B shown in FIG. 2, and is a diagram for explaining a drive mechanism of the encoder scale. In FIG. 3, a part of the illustration is omitted.

  As shown in FIG. 1, the image forming apparatus 1 includes a carriage 3 and an encoder unit 4 in a housing 2.

  The carriage 3 is equipped with an ink jet recording head (hereinafter simply referred to as “head”) 6 for ejecting ink, and conveys the head 6 in the main scanning direction (movement direction) A.

  A guide shaft 7 spanning in parallel with the left and right side walls of the housing 2 is slidably passed through the carriage 3 and slidable with respect to the carriage 3, and a drive pulley 8 provided in the housing 2. A part of the endless timing belt 10 that is wound around the driven pulley 9 is attached. The timing belt 10 is provided so as to be substantially parallel to the guide shaft 7.

  That is, the carriage 3 is movable in the main scanning direction A while being slid along the guide shaft 7 by driving the timing belt 10 while the driving pulley 8 and the driven pulley 9 are rotationally driven by the driving motor 11. It has become.

  The carriage 3 has a housing (accommodating portion) 3A. A removable ink cartridge 31 for supplying ink to the head 6 is mounted in the housing 3A. Note that, for example, the ink cartridge 31 of the present embodiment includes four ink cartridges (not shown) that individually supply four colors of ink of yellow, cyan, magenta, and black.

  The head 6 mounted on the carriage 3 is composed of four inkjet heads (not shown) for individually ejecting inks supplied from the four color ink cartridges. These four ink jet heads are arranged in parallel in the main scanning direction A, and each ink jet head has a nozzle row in which a plurality of nozzles are arranged in a straight line on a downward nozzle surface.

  As shown in FIGS. 2 and 3, the encoder unit 4 is an encoder that detects the movement amount and position of the carriage 3, and includes an encoder scale (hereinafter simply referred to as “scale”) 41 and an encoder sensor unit (hereinafter simply referred to as “scale”). "Sensor unit") 42). The scale 41 is a rotary scale that has a predetermined pattern formed on concentric circles and is rotated according to the movement of the carriage. The sensor unit 42 detects the movement amount of the carriage 3 with the scale 41 as a reference, and detects a predetermined pattern formed on the scale 41 and outputs a predetermined signal.

  In the image forming apparatus 1 according to the present embodiment, the disk-like scale 41 rotated by a predetermined drive mechanism is provided in the housing 3 </ b> A in which the head 6, in particular, the nozzle portion for ejecting ink is disposed outside. While being rotatably supported, the sensor unit 42 is fixed at a position where a predetermined pattern P formed on the scale 41 in the housing 3A can be detected.

  Further, the scale 41 of the present embodiment is a transparent disk-shaped member made of resin or the like, and the scale 41 is formed with the light and dark pattern as the predetermined pattern P along the outer peripheral edge. Is.

  The drive mechanism for rotating the scale 41 includes a guide shaft 12 that is stretched in parallel with the left and right side walls of the housing 2, a rack 13 that is fixed to the guide shaft 12, and rack teeth 13 a of the rack 13. 14A, a shaft member 14B to which the gear 14A and the scale 41 are fixed, and two bearing members 32A and 32B for rotatably supporting the shaft member 14B. The two bearing members 32A and 32B are fitted into two holes 3a and 3b formed in the housing 3A, respectively.

  Further, the housing 3A is not formed with an opening such as a hole other than the two holes 3a and 3b, and the shaft member 14B is rotatably supported by the two bearing members 32A and 32B. Thus, the housing 3A is closed from the outside and is in a substantially sealed state.

  Further, as shown in FIG. 2, the guide shaft 12, the rack 13, the gear 14A, and a part of the shaft member 14B are arranged outside the housing 3A. That is, the housing 3 </ b> A is formed with a recess 33 that forms a space allowing the rotation of the gear 14 </ b> A, and holes 3 a and 3 b are respectively formed on two side surfaces constituting the recess 33.

  In the example of FIGS. 2 and 3, the gear 14A and the scale 41 are fixed to the same shaft member 14B for the purpose of preventing or suppressing a decrease in accuracy of movement control of the carriage 3 due to rattling between the power transmission members. However, the present invention is not limited to this, and other gears for transmitting the driving force of the gear 14 </ b> A driven by the movement of the carriage 3 to the scale 41 between the gear 14 </ b> A and the scale 41. It is also possible to interpose a gear or a shaft member.

  FIG. 4 is a cross-sectional view when viewed in the direction of the arrow from the YY line shown in FIG. 3, and is a diagram for explaining the configuration of the sensor unit 42.

  As shown in FIG. 4, the sensor unit 42 has one transmissive sensor 42 </ b> A including a light emitting unit 421 as a light source and a light receiving unit 422 that receives light. The light emitting unit 421 and the light receiving unit 422 are disposed to face each other with the scale 41 interposed therebetween.

  More specifically, a rectangular parallelepiped 2 for holding the light emitting part 421 and the light receiving part 422 at a predetermined distance on the inner side surface (ceiling surface) of the housing 3A so as to form a space for sandwiching the scale 41 therebetween. Two holder members 420A and 420B are provided.

  That is, when the sensor unit 42 moves together with the carriage 3, the light receiving surface 422 receives light emitted from the light emitting surface 421 via the predetermined light / dark pattern P formed on the scale 41. A predetermined signal (not shown) is output to a sensor controller 42C described later.

  Specifically, the light receiving surface 422 is turned on when the light receiving surface 422a receives light through the bright pattern portion of the light / dark pattern P, and receives light through the dark pattern portion of the light / dark pattern P. In this case, an ON / OFF signal that is turned off is output.

  2 and 3, the sensor unit 42 is directly fixed to the inner surface of the housing 3A. However, the present invention is not limited to this, and the sensor unit 42 is fixed to the inner surface of the housing 3A via another support member. You may make it.

  That is, in the image forming apparatus 1 according to the present embodiment, the scale 41 and the sensor unit 42 are always supported in the substantially sealed housing 3A, and therefore the scale 41 (particularly, the predetermined pattern P) and the sensor. It is possible to prevent or suppress the ink discharged from the recording head, the ink mist floating in the housing, and the like from adhering to the unit 42 (particularly, the light emitting surface 421 and the light receiving surface 422).

  The image forming apparatus 1 includes a main control board 5 in the housing 2. The main control board 5 is a board on which various electronic components such as a CPU (Central Processing Unit) 51 (see FIG. 5) for controlling the processing operation of the image forming apparatus 1 are mounted. The movement of the carriage 3 is controlled based on a signal output from the sensor unit 42 in cooperation with the above.

  Further, the image forming apparatus 1 further includes a paper transport unit 14 in the housing 2. The paper transport unit 14 rotates the transport roller 16 by a drive motor 15, thereby transporting a recording paper MP as a recording medium from a paper feed tray (not shown) in a transport direction C (a direction toward the side viewing FIG. 1). ).

  FIG. 5 is a block diagram for explaining a hardware configuration of the image forming apparatus 1, and particularly shows a circuit configuration of the main control board 5 and other circuit configurations other than the main control board 5.

  As shown in FIG. 5, the image forming apparatus 1 includes a main control board 5 in a housing 2. Specifically, the image forming apparatus 1 is connected to a CPU 51 via the CPU 51 and a bus line BL. ROM (Read Only Memory) 52, RAM (Random Access Memory) 53, non-volatile memory 54, sensor unit 42, head drive unit 60, carriage drive unit 30, paper transport unit 14, communication I / O In addition to the F unit 55, a power supply unit 56 that supplies power to each component unit is provided.

  Here, the CPU 51 controls the entire image forming apparatus 1 by developing and executing a program stored in the ROM 52 in the RAM 53.

  The ROM 52 stores various programs such as a program for executing processing procedures in a flowchart described later, and files such as various data used in the processing of the various programs. The RAM 53 temporarily stores working data. The nonvolatile memory 54 stores print data in PDL format received from a host computer (not shown) via the communication I / F unit 57, image data obtained by analyzing the print data, and the like.

  The sensor unit 42 includes a sensor 42A and a sensor controller 42C that is electrically connected to the sensor unit 42 and controls the sensor 42A. For example, the sensor controller 42 </ b> C is provided near one end surface in the housing 30 of the carriage 3.

  Then, under the control of the CPU 51, the sensor controller 42C controls the light emission of the light emitting unit 421 of the sensor 42A or the input process of the output signal from the light receiving unit 422 of the sensor 42A. Controls the position detection process.

  The head driving unit 60 includes a head 6 and a head controller 61 that is electrically connected to the head 6 and controls the head 6. For example, the head controller 61 is provided in the housing 3 </ b> A of the carriage 3.

  The head controller 61 controls the timing of ejecting ink from the head 6, the ejection amount of ink ejected from the head 6, and the like under the control of the CPU 51.

  The carriage drive unit 30 includes a drive motor 11 and a drive controller 32 that is electrically connected to the drive motor 11 and controls the drive motor 11. For example, the drive controller 32 is mounted on the main control board 5.

  The drive controller 32 controls the movement of the carriage 3 by controlling the amount of rotation of the drive motor 11 under the control of the CPU 51.

  The paper transport unit 14 includes a drive motor 15 and a drive controller 17 that is electrically connected to the drive motor 15 and controls the drive motor 15. For example, the drive controller 17 is mounted on the main control board 5.

  The drive controller 17 controls the conveyance of the recording paper MP by controlling the rotation amount of the drive motor 15 under the control of the CPU 51.

  The communication I / F unit 55 is an interface that transmits and receives various data to and from a host computer connected via a communication cable (not shown), and receives print data from the host computer.

  The power supply unit 56 converts power supplied from a commercial power source or the like into power necessary for each component and supplies the power.

  The above-described program is provided in a form that can be installed or executed in addition to being provided in advance in the ROM 52 or the like, provided by being recorded on a computer-readable recording medium, or via a network. Or can be provided.

  Next, the processing operation of the image forming apparatus 1 will be described.

  FIG. 6 is a flowchart for explaining the overall processing flow in the image forming apparatus 1.

  As shown in FIG. 6, when the image forming apparatus 1 first receives print data in PDL format from the host computer via the communication I / F unit 55 under the control of the CPU 51 in step S <b> 1, the RAM 53 and the nonvolatile memory. The received print data is stored in the memory 54.

  Subsequently, under the control of the CPU 51, the image forming apparatus 1 repeatedly executes the processes in step S2 and step S3 until all image formation based on the print data received in step S1 is completed.

  Specifically, in the process of step S2, the image forming apparatus 1 performs data analysis of the PDL format print data stored in the RAM 53 under the control of the CPU 51, and generates, for example, page-unit image data. .

  In the process of step S3, the image forming apparatus 1 executes an image forming process for forming an image on the recording paper MP based on the page unit image data generated in step S2.

  Specifically, in the image forming process of step S <b> 3, the image forming apparatus 1 performs a process in which the sensor controller 42 </ b> C of the sensor unit 42 controls the driving of the sensor 42 </ b> A under the control of the CPU 51. A process in which the drive controller 32 controls the movement of the carriage 3, a process in which the head sensor controller 61 of the head drive unit 60 controls the drive of the head 6, and a drive controller 17 in the paper transport unit 14 transports the recording paper MP. Execute the process to control.

  Then, when all image formation based on the print data received in step S1 is completed, the processing here is terminated.

  Of the various processes in step S3 described above, as the process related to the movement control of the carriage 3, in the image forming apparatus 1, the sensor controller 42C is under the control of the CPU 51 until the image formation for each page is completed. The signal output from the sensor 42A is input. Then, the sensor controller 42C calculates the position information of the carriage 3 based on “ON” / “OFF” of the input signal, and passes the calculated position information to the CPU 51. Then, the CPU 51 outputs a control signal indicating the movement amount of the carriage 3 to the drive controller 32 of the carriage drive unit 30 based on the received position information and image data in page units. Then, the drive controller 32 controls the movement of the carriage 3 by controlling the amount of rotation of the drive motor 11 based on the input control signal.

  That is, according to the embodiment described above, it is possible to control the movement of the carriage with high accuracy (high resolution) without being affected by the ink, and thereby the quality of image formation (that is, print quality). Therefore, an image forming apparatus having a high image quality can be provided.

  More specifically, according to the present embodiment, since both the scale and the sensor are accommodated and supported in a substantially hermetically sealed housing, ink (that is, ink ejected from the recording head) In addition, it is possible to prevent or suppress the adhesion of ink mist floating in the housing), so that it is possible to control the movement of the carriage with high accuracy (high resolution) and to achieve high image formation quality. Can be provided.

  In addition, according to the present embodiment, the rack is fixed to a member having high strength such as a guide member for guiding the carriage. Therefore, the strength of the rack can be increased, and the rack can be bent due to the deflection of the rack. The backlash with the gear can be prevented or suppressed.

  As mentioned above, although demonstrated based on exemplary embodiment, this embodiment is not limited by above-described embodiment.

  For example, in the above-described embodiment, the case of the housing 3A of the carriage 3 having a space that can also accommodate the ink cartridge 31 as the accommodating portion that accommodates the scale 41 and the sensor unit 42 has been described. The accommodating portion that accommodates 41 and the sensor unit 42 may be a housing portion that is attached to a housing that accommodates the ink cartridge 31 and has a space that can accommodate only the scale 41 and the sensor unit 42.

  Further, in the above-described embodiment, the case where the rotary scale 41 is configured by a transparent disk-shaped member on which a predetermined light and dark pattern is formed has been described. However, the present invention is not limited to this, and the rotary scale 41 is predetermined on a concentric circle. It is also possible to use a scale composed of a disk-shaped member in which a plurality of slit holes are formed with an interval of.

  In the above-described embodiment, the case where the two guide shafts 7 and 12 are provided as the guide member for guiding the carriage 3 in the main scanning direction A has been described. It is also possible to adopt a form in which a guide shaft other than the two guide shafts 7 and 12 is further provided.

  For example, in the above-described embodiment, the case of an ink jet image forming apparatus having only a printer function (image forming function) has been described. However, in addition to the printer function, for example, a facsimile function and a scanner function It is also possible to provide a multifunction machine type image forming apparatus having other functions such as.

  In addition, the hardware configuration of the image forming apparatus, the layout of various components such as the scale and the sensor unit, the type of the recording medium and the ink, and the like in the above-described embodiments are merely described as examples. Are not limited thereto.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Case 3 Carriage 4 Encoder part 5 Main control board (control means)
6 Recording head (head)
7, 12 Guide shaft 8 Drive pulley 9 Drive pulley 10 Timing belt 11 Drive motor 13 Rack 13a Rack tooth 14A Gear 14B Shaft member 15 Drive motor 16 Transport roller 3A Housing 31 Ink cartridge 41 Encoder scale 42 Sensor unit 42A Sensor 42C Sensor controller ( Control means)
421 Light-emitting part 422 Light-receiving part 420A, 420B Holder member 51 CPU
52 ROM
53 RAM
54 Non-volatile memory 55 Communication I / F unit 56 Power supply unit BL Bus line 60 Head drive unit 61 Head controller 30 Carriage drive unit 32 Drive controller 17 Drive controller

Claims (3)

A carriage equipped with a head for ejecting ink;
A scale that is rotated in accordance with the movement of the carriage and has a predetermined pattern formed on a concentric circle;
A sensor for detecting the predetermined pattern of the scale;
A storage section provided on the carriage, storing the scale and the sensor, and preventing the ink discharged from the head from adhering to the stored scale and sensor ;
A bearing member fitted in a hole formed in the housing portion;
A shaft member supported by the bearing member;
A gear for transmitting power to the shaft member;
A rack having teeth engaged with the gear and disposed along a moving direction of the carriage,
The scale is an image forming apparatus in which the gear and the shaft member are driven in accordance with the movement of the carriage, and the scale is rotated in the housing portion sealed by the bearing member and the shaft member . A guide shaft member for guiding the carriage in the moving direction;
Further comprising
The image forming apparatus according to claim 1 , wherein the rack is provided on the guide shaft member. The predetermined pattern is composed of bright and dark pattern or more slits, the image forming apparatus according to claim 1 or 2.

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