JP2007050560A - Ink mist adhesion prevention device of scale for ink jet printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent ink mist scattering during print operation from adhering easily to a linear encoder scale or a rotary encoder scale made of a plastic film. <P>SOLUTION: Along the operating direction of the print sheet feed motor of an ink jet printer and the drive motor of a print head, a rotary encoder scale 18 and a linear encoder scale 21 made of plastic are provided. On one or both sides of the rotary encoder scale and the linear encoder scale, a metal film 27 is formed excepting the reading range by encoder sensors 19 and 22 for reading graduation and the surface of the metal film 27 is earthed to the metal chassis, or the like, of the ink jet printer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink mist prevention device for preventing ink mist scattered during printing from adhering to a linear encoder scale made of plastic film and a rotary encoder scale used in an ink jet printer.

In general, an ink jet printer is provided with a paper feed mechanism for feeding a set print paper in a certain direction and a head feed mechanism for moving a print head unit in a direction orthogonal to the paper feed direction. The print head unit is provided with a plurality of nozzles, and prints by ejecting ink from the nozzles while feeding the print paper in a certain direction and moving the print head unit in a direction perpendicular to the paper feed direction. To go.
A rotary encoder scale and a linear encoder scale are arranged in the paper feed mechanism and the head feed mechanism, respectively, and how much the print paper is fed and how much the print head unit is moved is executed by the rotary encoder scale. Is done. That is, the vertical feed of paper and the horizontal feed of the print head are performed by motors, and the amount of movement of feed by these motors is determined by the encoder scale. The timing at which ink is ejected from which nozzle is determined by a linear encoder scale.
That is, a scale pattern is formed at fine intervals on the encoder scale, and a sensor that reads the scale on the encoder scale is arranged on the print head unit. Then, the motor is operated until the sensor detects a predetermined number of scales from the scale serving as the reference of the rotary encoder scale, and is stopped simultaneously with the detection. Further, the sensor reads the scale of the linear encoder scale to determine the ink ejection timing from the nozzle. Therefore, accurate printing is performed by accurately detecting the scale of the encoder scale.
JP 2000-15595 A

However, the scale may be soiled by printing ink over a long period of use and its function may be impaired.
The reason for this is that when ink is ejected from the nozzle as a printing operation, or when ink particles hit the print paper or a part close to it and bounce off, a small part of the ink becomes mist and scatters. This is because it adheres to the surfaces of the linear encoder scale and the rotary encoder scale. In particular, borderless printing has become widespread in recent years, and since ink is printed overlapping the edge of the print paper and the outside thereof, ink mist tends to fly. In addition, it is thought that the surface of the plastics, which are materials of these scales, is easily charged by the action of static electricity, so that the ink mist clings to the surface in a relatively short time. In addition, since the reading sensor runs along the surface of the encoder scale, the moment when the ink mist adheres to the surface of the encoder scale is a minute dot, but it gradually increases and eventually the reading sensor The ink mist comes into contact with the ink mist and is stretched linearly along the moving direction, and the line becomes wider and spreads in a planar shape. The encoder scale is formed with stripe scales parallel to minute intervals, which are read by the reading sensor to control the motor operation. However, the above scales may cause reading defects due to contamination by ink mist. There is sex.
It is an object of the present invention to provide an ink mist adhesion preventing device for an ink jet printer scale that can make it difficult for ink mist scattered during printing to adhere to a linear encoder scale and a rotary encoder scale made of plastic film.

  In order to solve the above-mentioned problem, the invention according to claim 1 includes a plastic rotary encoder scale and a linear encoder scale, respectively, along the operation directions of the paper feed motor of the inkjet printer and the drive motor of the print head. A metal film is formed on one side or both sides of the rotary encoder scale and linear encoder scale except for the reading range of the scale reading encoder sensor, and this metal film surface is grounded to the metal chassis of the inkjet printer. It is characterized by that.

  According to the first aspect of the present invention, the metal film is formed on the rotary encoder scale and the linear encoder scale except for one or both sides of the reading range, and the metal film surface is grounded to the metal chassis or the like of the ink jet printer. The surface of the metal film is less likely to be charged, thereby reducing the amount of mist of the printing ink clinging, maintaining the original function for a longer time, and improving the durability as an encoder scale.

  FIG. 1 is a schematic view of a main part of an ink jet printer. In the figure, reference numeral 1 denotes a metal chassis. A paper feed roller 2 is disposed inside the chassis 1 in a direction orthogonal to the paper feed direction. A paper press roller 3 is disposed below the paper feed roller 2. The print paper P is sandwiched between the paper feed roller 2 and the paper press roller 3, and the print paper P is fixed by rotating the paper feed roller 2. Configured to send in the direction.

  Reference numeral 4 denotes a paper feed roller driving motor. The gear 5 provided on the output shaft of the motor 4 is engaged with a gear (not shown) provided on the rotation shaft 7 of the paper feed roller 2 via the reduction gear 6 so that the paper feed roller 2 is rotated. It has become. The rotating shaft 7 is made of metal, and one end (or both ends) of the rotating shaft 7 is in contact with the side wall 8 of the chassis 1 through a bearing 9.

  Next, two guide rods 10 are arranged in parallel with the paper feed roller 2, and a print head unit 11 is slidably supported by these guide rods 10. A nozzle (not shown) for ejecting printing ink is disposed below the print head unit 11.

  Reference numeral 13 denotes a print head unit driving motor. The motor 13 is disposed on one end side of the guide rod 10, a pulley 14 is disposed on the other end side, and a drive belt 16 is provided between the pulley 15 provided on the output shaft of the motor 13 and the pulley 14. A part of the driving belt 16 is fixed to the lower part of the print head unit 11.

  The printing paper P is disposed so as to move below the ink ejection nozzles of the print head unit 11 while being sandwiched between the paper feed roller 2 and the paper pressing roller 3.

  Next, when printing on the printing paper P by the paper feeding mechanism and the head unit feeding mechanism, it is performed by controlling the vertical paper feeding and the horizontal printer head unit feeding. The rotary encoder scale 18 provided on the rotary shaft 7 of the paper feed roller 2 is read by a transmission type reading sensor 19 to control the rotation amount of the rotary shaft 7. On the surface of the rotary encoder scale 18, stripe scales 20 with fine intervals are printed in the circumferential direction. The scales 20 are read by a reading sensor 19, and the sensor 19 is predetermined from the scale serving as a reference of the rotary encoder scale 18. The motor 4 is operated to the point where the number scale is detected, and is stopped simultaneously with the detection.

  Next, the feed and ink ejection of the print head unit 11 are controlled by reading the linear encoder scale 21 with a transmissive reading sensor 22. The linear encoder scale 21 is stretched by engaging hooks 24 of a mounting bracket 23 fixed to the side wall 8 of the chassis 1 with openings 25 formed at both ends of the linear encoder scale 21. A read sensor 22 is fixed to the print head unit 11 so that the linear encoder scale 21 can be read. On the surface of the linear encoder scale 21, stripe-shaped scales 20 are printed along the longitudinal direction, and the scales 20 are read by a reading sensor 22. The sensor 22 reads a predetermined number of scales from a reference scale. When this is detected, ink is ejected from the nozzles of the print head unit 11.

  In the above-described configuration, the printing paper P and the print head unit 11 are ejected from the nozzles of the print head unit 11 at a timing when the printing paper P and the print head unit 11 are fed by a predetermined feed amount in the vertical direction and the horizontal direction. It can be printed at a position, and characters and figures are printed by continuing this.

  2 to 5, the encoder scales (rotary encoder scale and linear encoder scale) 18 and 21 are both made of plastic, and the surface of the central base material 26 is fine except for both ends. Striped scales 20 are printed. On the surface of the base material 26, a metal film 27 is formed in a portion excluding the reading range of the scale reading encoder sensor.

The metal film 27 may be formed by the following method.
(1) A metal such as chromium, aluminum, nickel, gold or silver is deposited.
(2) Screen printing or painting is performed by selecting a printing or coating material in which metal powder or the like (aluminum, copper, gold, silver, carbon, etc.) is kneaded.
(3) A metal plate made of stainless steel, aluminum, brass or the like having the same size as the encoder scales 18 and 21 and having an open reading range is superposed and fixed to the encoder scales 18 and 21 by pressing, etching, or the like.

  The metal film 27 of the rotary encoder scale 21 is grounded to the chassis via the rotation shaft of the paper feed roller. Further, the metal film 27 of the linear encoder scale 18 is grounded to the chassis via a mounting bracket. To ground the metal film 27, a tension spring, a screw, caulking, or the like may be used.

  According to the above configuration, the portions of the encoder scales 18 and 21 covered with the metal film 27 are not charged with static electricity, so the encoder scale as a whole is not easily charged. Therefore, when ink is ejected from the nozzles during printing, or when ink particles hit the print paper and bounce off, a small portion of the ink becomes mist and scatters to form minute water droplets. Even if it floats in the chassis, it is difficult to attract to the surfaces of the encoder scales 18 and 21, and ink mist is difficult to adhere. Therefore, the scales of the encoder scales 18 and 21 are less likely to become dirty, and the original function can be maintained for a long time.

  The scale and sensor may be of a reflective type.

  Further, the metal film 27 may be attached only to the printing surface side of the encoder scale.

It is the schematic which shows the principal part of an inkjet printer. It is a perspective view of a rotary encoder scale. It is a perspective view which shows a part of rotary encoder scale in a cross section. It is a perspective view of a linear encoder scale. It is a perspective view which shows a part of linear encoder scale in a cross section.

Explanation of symbols

11 Print Head Unit 18 Rotary Encoder Scale 19, 22 Sensor 21 Linear Encoder Scale 27 Metal Film

Claims (2)

A plastic rotary encoder scale and a linear encoder scale are provided along the rotation direction of the paper feed motor of the printing paper of the inkjet printer and the operation direction of the print head unit, respectively.
A metal film was formed on one or both sides of the rotary encoder scale and linear encoder scale except for the reading range of the scale reading encoder sensor, and the metal film surface was grounded to the metal chassis of the inkjet printer. An ink mist adhesion prevention device for a scale for an inkjet printer. The mist wiping member that is in contact with the front surface or front and back surfaces of the rotary encoder scale and the linear encoder scale is attached in the vicinity of the encoder sensor for reading the rotary encoder scale and the linear encoder scale. 2. An ink mist adhesion preventing device for an inkjet printer scale according to 1.

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