JP2006289770A - Ink jet recorder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stable ink jet recorder which is free from defects due to the adhesion of ink mist to an encoder sensor and an encoder scale by effectively preventing the adhesion of ink mist suspended in the device. <P>SOLUTION: The open air is blown by a fan set integrally with the rotating encoder scale, whereby preventing the encoder sensor and the encoder scale from being adhered with ink mist. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus that performs recording on a recording medium by ejecting ink droplets with an ink jet recording head. More specifically, the present invention relates to an encoder scale, an encoder sensor, and the like that detect a transport amount of a transport unit that transports a recording medium. The present invention relates to a recording apparatus having a configuration for maintaining the performance of the detecting means.

  A printer is well known as a recording apparatus for recording desired recording information such as characters and images on a sheet-like recording medium such as paper or film. Various types of printer recording methods are known, but in recent years, ink-jet methods capable of non-contact recording on a recording medium such as paper are easy to color, and are quiet. Attention has been paid. In addition, as a configuration, a serial recording method that performs recording while mounting a recording head that ejects ink according to desired recording information and performing reciprocal scanning in a direction perpendicular to the feeding direction of a recording medium such as paper is inexpensive. In general, it is widely used because it is easy to downsize.

  On the other hand, as an environment surrounding recording devices such as printers, high-performance and low-cost electronic devices such as personal computers and digital cameras and scanners that are information input devices for these electronic devices are extremely widely used in general households. Printers are increasingly required to be lower in price, higher in recording quality, quieter in operation. In such a situation, a relatively inexpensive pulse motor or a DC motor rich in silence is generally used as a drive source for reciprocating scanning of the carriage in the carriage portion of the printer. In addition, in order to form recording information on a recording medium such as a sheet at a more accurate position, an encoder scale or an encoder sensor that detects a carriage position, a scanning speed, or the like is also used.

  As an encoder scale, for example, a photosensitive film is provided on the surface of a long film such as PET, and a pattern of light transmitting portions and shielding portions is alternately arranged at a predetermined pitch by a laser light exposure process and a subsequent development process. Some are provided along the direction. When using this scale, a printer is provided with a transmissive optical sensor facing the scale, and the carriage position and scanning speed are detected by the pattern on the encoder scale by scanning the carriage. The recording is performed based on this. In addition, various methods have been put to practical use for encoder scales and their sensors, such as using a reflective optical sensor by alternately providing high and low reflectance portions on a long film. A magnetic type or the like in which a magnetic pattern having different polarities at a predetermined pitch is provided on a scale-like or rod-like magnetic body and this pattern is detected by a magnetic sensor is known.

  FIG. 6 shows an example of a conventional ink jet printer.

  In FIG. 6, a recording head 22 having a nozzle portion that ejects ink according to recording information, a carriage 23 on which the recording head 22 is mounted, and a guide shaft that guides the carriage 23 in a direction perpendicular to the paper surface by a timing belt 29. 24, an ink tank 12 as a recording material supply means for supplying ink as a recording material to the recording head 22, and transmission of light at a predetermined interval to a long film for detecting the position and scanning speed of the carriage 23. Encoder scale 35 having a pattern in which portions and shielding portions are alternately arranged, an encoder sensor unit (not shown) provided on the carriage 23 for detecting the pattern of the encoder scale 35, and a carriage motor for moving and scanning the carriage 23 (this example) In this case, a DC motor is used). Note that the position of the carriage 23 during the recording operation is detected at any time by the pattern formed on the encoder scale 35 and the encoder sensor unit as the carriage 23 is scanned with the position of the predetermined position detection member as a reference. (For example, refer to Patent Document 1).

  In FIG. 6, the recording sheet is conveyed substantially horizontally below the carriage unit 23 with respect to the recording area by the recording head 22. That is, with respect to the recording area, the recording sheet is nipped by a pair of a conveyance roller (hereinafter also referred to as LF roller) 14 and a pinch roller 16 and conveyed by a predetermined amount.

  Control of the conveyance amount in this conveyance is normally performed based on a signal generated by an encoder mechanism having an encoder wheel that is directly attached to a conveyance roller and rotates. Specifically, as the encoder wheel 40 that rotates coaxially with the conveyance roller rotates, the encoder 50 signals and counts to know the rotation amount or rotation position, and the recording sheet conveyance amount is detected based on this. is doing. Then, when the detected transport amount reaches a predetermined amount, control is performed to stop the rotation of the motor that drives the transport roller and the like (see, for example, Patent Document 2).

  On the other hand, in order to enable printing of high-definition images such as photographs, the size of ink droplets that are ejected tends to decrease year by year in an inkjet printer. The ink droplets ejected from the recording head fly in the air and land on the recording medium to form an image. At the same time, very small ink droplets that do not reach the recording medium and float in the air are generated. To do. This is called ink mist. The ink jet recording head performs preliminary ejection toward the ink receiver in the printer at a predetermined timing for maintenance. At this time, since the distance to the ink receiver is farther than the distance to the recording medium, ink mist generated by preliminary ejection is used. Also occurs frequently.

  The ink mist floating in the printer may be discharged from the opening to the outside of the machine, but most of the ink mist adheres to the printer. Ink mist is a very small ink droplet, but if it adheres in large quantities, it causes various obstacles to the printer.

  Particularly in recent years, downsizing of the apparatus has been desired, and a so-called mobile printer having portability has a very small volume compared to a general desktop printer. Even in such a small printer, as described above, high-definition photographic image quality is required by reducing ink droplets. However, the smaller the volume in the housing, the higher the concentration of ink mist that is generated. The degree of adhesion increases. That is, when an image quality similar to that of a desktop is applied to a mobile printer or the like, the influence of mist is significantly higher than that of a desktop printer.

  Among the various obstacles caused by ink mist, one having the greatest influence is the adhesion of ink mist to the encoder scale, encoder wheel, and encoder sensor described above. This adhesion causes a problem in signal detection by the encoder, and as a result, the recording operation may become abnormal or the quality of the recording result may deteriorate.

  In order to solve such a problem, a means has been proposed in which a fan is provided in the apparatus to generate an air flow in the apparatus and ink mist is collected (for example, see Patent Document 5).

  In addition, a device having a cleaning means for cleaning the encoder scale and a device provided with a member for covering the encoder scale have been proposed (see, for example, Patent Documents 1, 3, and 4).

Specifically, as shown in FIG. 5, a light sensor by a light emitting diode 37 and a phototransistor 36 is arranged on the carriage side, and a cleaning means by a urethane resin 38 is attached to a holder that constitutes the light sensor. 35 is to be cleaned.
JP 2000-141802 A JP 2002-345277 A JP 2001-113772 A JP 2002-361901 A JP 2003-159824 A

  The present invention solves the problem that the ink mist as described above adheres to the encoder scale and the encoder sensor and interferes with the recording operation. Further, the solution as described in the above conventional example is particularly mobile printer. In such a small apparatus, the effect may be insufficient, and there is a problem that the apparatus cannot be accommodated in size. For example, even if the encoder scale can be cleaned with the conventional technology, the ink mist adhering to the optical sensor itself cannot be cleaned, and the possibility of malfunction due to the ink mist adhering to the optical sensor itself cannot be prevented. In particular, the encoder sensor is in a state where the ink mist is likely to adhere to the encoder sensor due to the rising airflow from the ink mist generation site.

  The present invention has been made paying attention to the above points, and effectively prevents the ink mist floating in the machine from adhering, and the ink mist adheres to the encoder sensor and encoder scale. It is an object of the present invention to provide a stable inkjet recording apparatus that does not occur.

In order to solve the above problems, according to the present invention, there is provided an inkjet recording apparatus that performs recording by ejecting ink droplets onto a recording medium,
Conveying means for conveying the recording medium;
Drive transmission means for transmitting a driving force to the recording medium conveying means;
An encoder scale provided coaxially with the drive transmission means;
An encoder provided opposite to the encoder scale for detecting a rotational direction position or speed of the recording medium conveying means;
Fins are provided integrally with the drive transmission means inside the encoder scale of the drive transmission means,
An opening for taking outside air into the machine is provided in the exterior facing the fin.

  According to the present invention, even in a recording apparatus having a small internal volume such as a mobile printer, the driving means for driving the conveying means is provided with the fin, and the opening for taking in the outside air is provided in the exterior of the position facing the fin. As a result, air flow from outside air is applied to the encoder sensor and encoder scale, effectively preventing ink mist floating in the machine from adhering to the encoder sensor and encoder scale. Therefore, it is possible to provide a stable ink jet recording apparatus that does not cause a malfunction.

  Compared with the conventional method using a fan, parts such as a drive gear and fins are integrally formed, so that it can be applied even to a small-sized device such as a mobile printer. It is advantageous.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows the entire recording operation mechanism of the ink jet recording apparatus according to an embodiment of the present invention, excluding the exterior.

  The recording operation mechanism in the ink jet recording apparatus according to the present embodiment is roughly classified as shown in FIG. 1. As shown in FIG. 1, an automatic sheet feeding unit that automatically feeds a recording sheet P (not shown) to a transport unit 200 in the apparatus main body. 100, the recording paper P sent out one by one from the automatic paper feeder 100 to the desired recording position, and discharge the recording paper P from the recording position, and the discharge located downstream of the transport unit 200 Unit 300, a recording unit 400 that performs desired recording on the recording sheet P conveyed to the conveying unit 200, and a recovery for maintaining the recording operation in a normal state with respect to the recording head 500 mounted on the recording unit 400 A recovery unit 600 that performs processing is provided, and each of these mechanism units is configured substantially integrally with a chassis 701 as a center, and an image forming operation is performed in cooperation with each other by a control unit.

  The conveyance direction of the recording sheet P is an arrow A in FIG. 1, and the reciprocating direction (scanning direction) of the recording unit 400 is an arrow B in FIG.

  The recording head cartridge 501 in this embodiment includes a recording head 500, a black ink tank cartridge 503 that can be attached to and detached from the recording head, and a color ink tank cartridge 504 that integrates three colors of cyan, magenta, and yellow. The recording head is a so-called ink jet recording head in which each color ink supplied from each ink tank 503, 504 is ejected as a droplet from an ejection port for a predetermined color according to recording information. As the ink jet method, a method of discharging by using foaming energy when the ink is heated, a method of discharging ink by vibration energy, or the like can be applied.

  FIG. 2 is a schematic view of the recording unit 400 as viewed from the front of the apparatus. FIG. 2A shows a state during printing, and FIG. 2B shows a state in which preliminary recovery for maintenance of the recording head 500 is performed in the recovery unit 600. .

  In the ink jet recording apparatus according to the present invention, image recording with a width corresponding to the nozzle row of the recording head 500 is performed on the recording paper P held on the platen 203 from the recording head 500 by one scan of the carriage 401. Thereafter, the recording paper P is fed by a predetermined amount by an unillustrated LF roller, and then the next image recording is performed by scanning the carriage 401 again to perform image formation.

  The ink droplets ejected from the recording head 500 are as small as several picoliters, and fly through the gap between the recording head 500 and the recording paper P and land on the recording paper P to form an image. At the same time, very minute ink mist is generated that does not reach the recording paper P and floats in the air.

  Ink mist is generated in the gap between the recording head 500 and the recording paper P. However, when the carriage 401 scans in the direction of arrow B in the figure, the space opens upward, so that the ink mist rises and extends in the entire travel space of the carriage 401. It spreads and is further diffused into the recording apparatus by the airflow generated by scanning the carriage 401.

  The ink jet recording apparatus according to the present invention performs preliminary ejection toward the preliminary ejection ink receiver 601 at the recovery unit 600 at a predetermined timing. At this time, since the distance to the preliminary ejection ink receiver 601 is longer than the distance to the recording medium, a lot of ink mist that does not reach the preliminary ejection ink receiver 601 and floats in the air is generated. In this case as well, ink mist is generated in the gap between the recording head 500 and the preliminary ejection ink receiver 601. However, when the maintenance operation is finished and the carriage 401 scans for the recording operation, a space is opened upward. Are diffused into the recording device.

  A part of the ink mist is discharged from the opening of the recording apparatus, such as the discharge port of the recording paper P, by the air flow generated by the scanning of the carriage 401. Most of the ink mist floats in the apparatus and gradually descends. Then, it adheres to every part in the recording apparatus such as the guide shaft 402, the platen 203, and the panel substrate 703. At this time, since the ink mist falls due to the influence of gravity, it tends to adhere to a horizontal surface in the recording apparatus.

  As described above, ink mist adheres to various places, but the ink mist adhering to the encoder 801 and the encoder scale 810 has a great influence on the operation of the recording apparatus. As described above, when the ink mist floats and adheres to the encoder scale, and the light from the encoder sensor does not pass through the encoder scale, the encoder cannot read a normal signal, causing a problem in the operation of the recording apparatus. Further, when ink mist adheres to the light receiving / emitting part of the encoder sensor, the encoder itself cannot emit light or the light receiving part cannot read the light, which may cause a serious problem in the recording operation. In particular, in a small-sized printer such as the present invention, the amount of ink mist floating in the apparatus per unit volume increases, so that the period of time when a problem occurs may be shortened.

  In the present invention, as shown in FIG. 3, fins 823 are integrally provided on a drive gear 822 that is a driving unit for driving a conveying unit for conveying the recording medium. An encoder scale 810 is attached to the drive gear 822 coaxially with the drive shaft 824, and the drive gear 822 and the encoder scale 810 rotate integrally. An encoder 802 is provided so as to sandwich the encoder scale 810. A pattern such as a light transmitting portion and a shielding portion provided at a predetermined pitch on the encoder scale is read, and the rotation amount and rotation speed of the drive transmission means are signalized. To do.

  When the drive gear 822 rotates, the fin 823 provided integrally with the drive gear 822 rotates, and pushes out the air staying between the fins toward the outer periphery of the drive gear 822. Outside the exterior, that is, outside the machine flows into the portion where the air is pushed out through a louver 831 provided in the exterior 830 facing the drive gear 822. Various louver shapes and opening sizes can be applied depending on the case. Various shapes and numbers of fins can be applied as well. In addition, since the direction of the airflow changes depending on the rotation direction of the fins, it is preferable that the rotation direction in which the air is pushed out by the fins in the outer peripheral direction of the drive gear 822 and the main rotation direction of the drive gear 822 are matched. However, the reverse is also applicable by adjusting the timing and time for rotating the fins as will be described later.

  As a result, as shown in FIG. 4, an air flow is generated toward the encoder scale 810 and the encoder sensor 802, and air that does not always contain fresh ink mist flows, so that ink mist is attached to the encoder scale 810 and encoder sensor 802. There is no problem of reading errors caused by the encoder.

  The drive gear 822 rotates while the recording medium is being transported and generates an air flow. However, the drive gear 822 is rotated at a predetermined timing, a predetermined time, or a rotation amount even when the recording medium is not being transported. The effect of preventing ink mist adhesion can be enhanced.

The perspective view except the exterior of the recording device main body of the present invention The side view showing the relationship between the carriage and head of the recording apparatus main body of the present invention The front view which shows the encoder periphery of the recording-medium conveyance system drive part of the recording device of this invention FIG. 3 is a side view showing the periphery of the encoder of the recording medium conveyance system drive unit of the recording apparatus of the invention The figure which shows the optical sensor part of a prior art example Perspective view showing a conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Automatic paper feed part 200 Conveyance part 203 Platen 300 Ejection part 400 Recording part 401 Carriage 402 Guide shaft 500 Recording head 501 Recording head cartridge 503 Black ink tank cartridge 504 Color ink tank cartridge 600 Recovery part 601 Pre-discharge ink receiver 701 Chassis 801 Encoder 810 Encoder scale 820 Encoder holder 821 Flexible member 822 Drive gear 823 Fin 824 Drive shaft 830 Exterior 831 Louver

Claims (1)

An inkjet recording apparatus that performs recording by ejecting ink droplets onto a recording medium,
Conveying means for conveying the recording medium;
Drive transmission means for transmitting a driving force to the recording medium conveying means;
An encoder scale provided coaxially with the drive transmission means;
An encoder provided opposite to the encoder scale for detecting a rotational direction position or speed of the recording medium conveying means;
Fins are provided integrally with the drive transmission means inside the encoder scale of the drive transmission means,
2. An ink jet recording apparatus according to claim 1, wherein an opening for taking outside air into the apparatus is provided in the exterior facing the fin.