JP4191958B2 - Optical beam recording device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a light beam recording apparatus that records information on a recording medium by irradiating the recording medium with a beam.
[0002]
[Prior art]
  As a conventional technique for recording information by beam exposure, a technique mainly including a polygon mirror that deflects and scans a beam irradiated from a light source onto a photosensitive member and an fθ lens is widely used. Is sensitive and suitable for high-speed recording.
[0003]
  Separately, a recording method is known in which a recording medium having a surface of a thermosensitive coloring layer coated with a light-to-heat conversion material is irradiated with a beam and colored by heat generated at the irradiation position of the beam to record information. . Such a recording method is used in the case of producing a block or the like. The exposure method for the block or the like is performed by scanning light on a recording medium with a galvano mirror, a rotating mirror, a polygon mirror, or the like. Recording methods are generally employed, but these are large devices. As other types of conventional techniques, an outer surface exposure method and an inner surface exposure method are given as typical examples.
[0004]
  In the inner surface exposure method, a recording medium is mounted on the inner surface of a cylindrical drum, a rotating mirror that rotates about the center line of the drum is provided, and the recording medium is a rotating mirror that rotates a beam irradiated on the center line of the drum. This is a scanning method. Since the drum does not rotate in this internal exposure method, there is an advantage that there is little influence of mechanical vibration and rotation unevenness of the drum at the time of writing, but since the number of rotations of the mirror is not set to tens of thousands of rotations because there is one light source, There is a disadvantage that the writing time becomes long. In order to smoothly rotate the mirror at a high speed of several tens of thousands of revolutions, an expensive fluid bearing is usually used. Further, the rotation control accuracy is required to be very high, and the cost of the apparatus is very high.
[0005]
  As described in JP-A-6-186750 and the like, the outer surface exposure method is a method in which a recording medium is attached to the outer peripheral surface of a drum, and the recording medium is irradiated with a beam from the outside while rotating the drum. In order to accurately determine the recording position of information, this outer surface exposure method needs to prevent drum rotation unevenness.To that end, in addition to improving the accuracy of the power transmission system, means for detecting drum rotation unevenness, Rotation unevenness correcting means or the like is required, which increases the cost.
[0006]
  Further, as described in Japanese Patent Application Laid-Open No. 2000-131628, in an image recording apparatus that forms an image on a recording medium on a recording rotating drum by modulating light emitted from a light source with a light modulation element, the light source There is an invention in which a high-power laser is used and the light modulation element is configured as a reflection diffraction grating type light modulation array in which a plurality of grating light valve elements are arranged at least in the width direction of the recording rotary drum. There is no description about measures to determine the positional accuracy of the direction.
[0007]
  Furthermore, as described in Japanese Patent Application Laid-Open No. 2000-318115, a plate mounting drum, a laser block having a high-power laser beam irradiation unit that irradiates a laser beam on the plate mounted on the drum, A controller for driving a drum and a laser block and controlling a high-power laser beam irradiation unit to irradiate a predetermined position on the plate with a laser beam; a main scanning encoder and a sub-scanning encoder for detecting a drawing position on the plate; An invention of a drawing apparatus and a drawing method comprising an autofocus unit for measuring the distance between the drawing mechanism and the surface of the plate, and a defective part counting / determining device for determining whether or not the measurement result is within an allowable range. However, since various control devices such as an encoder for detecting the drawing position are used, the cost may increase.
[0008]
[Problems to be solved by the invention]
  An object of the present invention is to provide a light beam capable of recording information in a two-dimensional region by a relative swinging operation in a one-dimensional direction between a light source on an optical head and a converging optical system and a rotating operation of a drum. It is to provide a recording device.
[0009]
  An object of the present invention is to provide a light beam recording apparatus capable of accurately recording information in a wide range in the axial direction of a drum.
[0010]
  An object of the present invention is to provide a light beam recording apparatus capable of suppressing the rotation unevenness of the drum with a simple structure and accurate in the information recording position on the recording medium.
[0011]
[Means for Solving the Problems]
  The invention according to claim 1 is an optical head having a drum for holding a recording medium, a light source and a converging optical system for converging a beam emitted from the light source onto the recording medium on the drum, and the light source. Oscillating means for relatively oscillating at least one of the focusing optical system and the recording surface of the recording medium, a driving source connected coaxially to the drum and rotationally driving the drum,Optical head scanning means for driving the optical head to reciprocate along the axial direction of the drum;It comprises.
[0012]
  Therefore, information can be recorded in the two-dimensional area of the recording medium on the drum by the relative swinging operation of the light source and the converging optical system and the rotating operation of the drum. In this case, by connecting the drum coaxially to the drive source, it is possible to reduce the number of rotation transmitting members and suppress the rotation unevenness of the drum.
Further, by scanning the optical head, it is possible to enlarge an information recording area free from distortion and density unevenness in the drum axial direction.
[0013]
  According to a second aspect of the present invention, there is provided an optical head having a drum for holding a recording medium, a light source and a converging optical system for converging a beam emitted from the light source onto the recording medium on the drum, and the light source. Oscillating means for relatively oscillating at least one of the converging optical system along the recording surface of the recording medium, a driving source for rotationally driving the drum, and the drum and the driving source N ( (Natural number): a power transmission gear device connected at a gear ratio of 1:Optical head scanning means for driving the optical head to reciprocate along the axial direction of the drum;It comprises.
[0014]
  Therefore, information can be recorded in the two-dimensional area of the recording medium on the drum by the relative swinging operation of the light source and the converging optical system and the rotating operation of the drum. In this case, by connecting the drum to the drive source at a gear ratio of N: 1, it is possible to suppress the rotation unevenness of the drum and the positional deviation in the rotation direction of the drum.
Further, by scanning the optical head, it is possible to enlarge an information recording area free from distortion and density unevenness in the drum axial direction.
[0015]
  Claim3The described invention is claimed.1 or 2In the described invention, a stepping motor or a servo motor is used as the drive source.
[0016]
  Therefore, the profile of the beam irradiation position in the drum rotation direction can be made reproducible.
[0017]
  Claim4The invention described in claim 1 to claim 13In any one of the inventions, the drive source is supported by a high-rigidity member without interposing an elastic member having a silencing property.
[0018]
  Therefore, the drive source can be firmly fixed.
[0019]
  Claim5The described invention is claimed.1In the described invention, the drum and the drive source are connected to each other by a joint having no play in the rotation direction with respect to the output shaft of the drum and the drive source.
[0020]
  Therefore, when the weight of the drum is unbalanced, the occurrence of uneven rotation of the drum caused by external vibrations is suppressed.
[0021]
  Claim6The described invention is claimed.1In the described invention, the drum and the drive source are connected by a speed reducer.
[0022]
  Therefore, it is possible to increase the rotational resolution of the drum.
[0023]
  Claim7The described invention is claimed.Any one of 1-6In the described invention, a swinging direction for relatively swinging the light source and the converging optical system is set to a direction equal to a scanning direction of the optical head.
[0024]
  Therefore, it is possible to enlarge the information recording area in the axial direction of the drum by scanning the optical head.
[0025]
  Claim8The described invention is claimed.7In the described invention, the scanning length of the optical head is determined to be longer than the scanning length of the beam obtained by relatively swinging the light source and the converging optical system.
[0026]
  Therefore, as the beam scanning length is increased by relatively swinging the light source and the converging optical system, the beam spot at the end of the scanning length is distorted and the optical density is reduced. By scanning the entire head, it is possible to enlarge an information recording area free from distortion and density unevenness in the axial direction of the drum.
[0027]
  Claim9The described invention is claimed.1 to 8In any one of the inventions, the optical head scanning unit includes a scanning position detection unit that detects a position of the optical head in the scanning direction.
[0028]
  Therefore, it is possible to scan the optical head to a desired position while detecting the position of the optical head.
[0029]
  Claim10In the invention described in claim 2, in the invention described in claim 2, the power transmission gear device directly meshes the drum gear fixed to the drum and the drive gear fixed to the drive source.
[0030]
  Accordingly, it is possible to improve the followability of the drum with respect to the drive source and further suppress the uneven rotation of the drum.
[0031]
  Claim11The described invention is claimed.1In the described invention,in frontThe recording head is arranged along the axial direction of the drum.MultipleIt is arranged.
[0032]
  Therefore, it becomes easy to align information recording positions in a line along the axial direction of the drum.
In addition, since information can be recorded using a plurality of optical heads along the axial direction of the drum, the information recording area in the axial direction of the drum can be expanded. In this case, by connecting the drum coaxially to the drive source, it is possible to reduce the number of rotation transmitting members and suppress the rotation unevenness of the drum.
[0033]
  Claim12The described invention is claimed.11In the described invention, the plurality of optical heads are arranged in a staggered manner over two or more rows along the axial direction of the drum.
[0034]
  Therefore, it is possible to increase the speed of information recording.
[0035]
  Claim13The described invention is claimed.12In the described invention, all the optical heads are supported so that the recording positions are aligned on a single straight line along the axial direction of the drum.
[0036]
  Therefore, it is possible to increase the density of information recorded in the line direction.
[0037]
  Claim14The described invention is claimed.Any one of 11-13In the described invention, the converging optical systems or the light sources of the optical heads are supported by a common support member.
[0038]
  Therefore, it is possible to swing the converging optical systems or light sources of all the optical heads together with one support member by one swinging means.
[0039]
DETAILED DESCRIPTION OF THE INVENTION
  A first embodiment of the present invention will be described with reference to FIGS. 1 is a plan view showing a light beam recording apparatus, FIG. 2 is a side view thereof, FIG. 3 is an explanatory view showing a sequence of a rewritable recording medium, FIG. 4 is a sectional view of a drum, and FIG. FIG. 6 is an explanatory view showing beam deflection caused by relative oscillation between the light source and the converging optical system, and FIG. 7 shows a connection structure between the drum and the drive source. FIG. 8 is a partial plan view showing a modified example of the connection structure between the drum and the drive source, FIGS. 9 and 10 are explanatory views showing the scanning state of the beam with respect to the recording medium, and FIG. FIG. 12 to FIG. 14 are explanatory views showing the scanning state of the beam with respect to the recording medium.
[0040]
  As shown in FIGS. 1 and 2, the light beam recording apparatus P1 in the present embodiment includes a drum 2 for holding the recording medium 1, a drive source 3 for driving the drum 2, and a recording medium 1. And a recording medium supply unit 4 for recording information on the recording medium 1, and an optical head 8 having a light source 5 and a lens 6 as a converging optical system mounted on a base 7 as means for recording information on the recording medium 1. The drive source 3 is a motor. At that time, since high-precision position control is required, it is necessary to be able to control the rotational position of the motor. Therefore, a stepping motor, a servo motor, or the like is generally used as the drive source 3, but these motors may be controlled by a control method using a rotary encoder. In the following description, the drive source will be referred to as the motor 3. The motor 3 is specifically a stepping motor or a servo motor.
[0041]
  In this example, the recording medium supply unit 4 includes a supply shaft 9 that supports the recording medium 1 wound in a roll shape, a pair of conveyance rollers 10 that pulls out the recording medium 1 from the supply shaft 9, and a recording medium that has been drawn out. 1 has a recording medium sensor 11 whose on / off operation is switched when the leading edge of 1 is reached, and a cutter 12 which cuts the drawn recording medium 1 into a desired size. The cutter 12 cuts the recording medium 1 when driven by the rail-shaped guide 13 and driven. As the recording medium sensor 11, a reflection type or transmission type photo interrupter is generally used, or a detection method with a filler is often used.
[0042]
  The drum 2 has a clamp 14 that is provided at a part of the outer periphery and detachably holds both ends of the recording medium 1 that is cut, and a drum shaft 15 that protrudes from the center of both ends. A metal housing (high rigidity member) 16 is rotatably supported via a bearing. One end of the drum shaft 15 and the output shaft 17 of the motor 3 are coaxially connected by a joint 18.
[0043]
  The recording medium 1 has a recording layer that produces heat-sensitive color, is a medium on which information is recorded by a beam such as a laser beam, and the recorded information can be optically read. This recording medium 1 is a write-once recording medium 1 such as Ricoh Co., Ltd., TF3100-S, TF3101-F, or the like. As the recording medium 1, the rewritable recording medium 1 described in the following description is also applicable.
[0044]
  The rewritable recording medium 1 described here can form a relatively colored state and a decolored state depending on the heating and cooling after heating. This basic coloring / decoloring phenomenon will be described with reference to FIG. FIG. 3 shows the relationship between the color density (vertical axis) and the temperature (horizontal axis) of the composition of the recording medium 1. When the temperature of the composition in the initially decolored state (A) is raised, the temperature T at which it begins to melt₁Color development occurs and the molten color state (B) is obtained. When rapidly cooled from the melt color state (B), the color state can be lowered to room temperature and a solid color state (C) is obtained. Whether or not this color development state is obtained depends on the rate of temperature decrease from the molten state. In slow cooling, the color disappears in the process of temperature decrease, and the same color disappearance state (A) or rapid color development state (C ) A relatively low concentration state is formed. On the other hand, when the rapid color development state (C) is heated again, the temperature T lower than the color development temperature.₂Then, decoloring occurs (D to E), and when the temperature is lowered from here, the same decoloring state (A) as the beginning is restored. The actual color developing temperature and color erasing temperature vary depending on the combination of the developer and color former used, and can be selected according to the purpose. Further, the density of the melt coloring state and the coloring density when rapidly cooled are not necessarily the same and may be different.
[0045]
  Therefore, when writing information on the rewritable recording medium, the color recording is performed by heating to a temperature at which it is melted and mixed by a laser light source, a thermal head, or the like and then rapidly cooling. In addition, there are two methods of erasing: a method of slowly cooling from a heated state and a method of heating to a temperature slightly lower than the coloring temperature. However, the two methods are the same in the sense that the developer and the color former are phase-separated, or at least one of the developer and the color developer is temporarily maintained at a temperature at which crystallization occurs. The reason for quenching when developing the color is to prevent the temperature from being maintained at the above phase separation or crystallization temperature. However, rapid cooling and slow cooling here are relative to one composition, and the boundary changes depending on the combination of the color former and the developer. Therefore, it is necessary to control the temperature according to the composition used. There is.
[0046]
  The drum 2 for holding the recording medium 1 is determined by the size of the recording medium 1 used by the light beam recording apparatus P1 with respect to the outer diameter. For example, if the recording medium 1 corresponding to the A1 size is used, the recording medium 1 has a long side of 840 mm and a short side of 594 mm. Therefore, the outer diameter of the drum 2 is required to be at least 594 / π = 189.2 mm. If you want to reduce the size in the axial direction, it will be adjusted to the long side, so 840 / π = 267.5 mm is required. Moreover, in order to prevent the rotation nonuniformity at the time of driving the drum 2, it is better to have a weight balance in the rotation direction. In other words, it is desirable to have a complete cylindrical shape, but it is necessary to provide a clamp 14 for holding the recording medium 1, which causes a bias in the weight balance. Therefore, it is desirable to attach a counterweight 19 on the opposite side of the clamp 14 as shown in FIG. Alternatively, when the notch 20 is formed in a part of the outer periphery of the drum 2 in order to attach the clamp 14, and the weight of a part of the outer periphery of the drum 2 is reduced by the notch 20, the thickness at the opposite position is increased. It is desirable to form a recess 21 with a reduced thickness.
[0047]
  The recording medium supply unit 4 has an example of the configuration shown in FIGS. 1 and 2 because many of the recording media are roll-shaped. However, when the recording medium 1 having a specified size is used, the recording medium supply unit 4 Instead of 4, a recording medium supply unit 22 as shown in FIG. The recording medium supply unit 22 is configured to sequentially pull out the recording medium 1 of a specified size stacked on the recording medium tray 23 from the upper layer by the paper feeding roller 24 and deliver it to the conveying roller 10.
[0048]
  The principle of beam scanning performed only by the optical head 8 is shown in FIG. This beam scanning can achieve the same effect even if only the light source 5, only the lens 6, or both are swung. When the light source 5 and the lens 6 are swung simultaneously, both are swung so that the swinging directions are opposite to each other. Here, a case where only the lens 6 is swung by a swing mechanism 25 as a swinging means will be described. The light source 5 and the lens 6 are adjusted in optical axis and are substantially focused on the recording position of the recording medium 1. When the lens 6 is swung along the surface of the recording medium 1, the beam position on the recording medium 1 moves accordingly, but the moving distance moves many times as compared with that of the lens 6. Although the beam amplitude on the recording medium 1 depends on the design of the optical system, it can be several times to more than a dozen times the amplitude for swinging the lens 6. In principle, at the end of the beam amplitude width on the recording medium 1, the cross-sectional shape and spot shape of the light beam are expected to change and the recording characteristics are expected to deteriorate, so it is necessary to record with high image quality. In this case, it is preferable to use an aspheric lens, but a spherical lens may be used, and this is not a limitation of the present invention. If the magnification of the amplitude is increased too much, the distortion on the recording medium 1 will increase even if an aspheric lens is used. As the actuator of the swing mechanism 25 that swings the lens 6, all of rotary motors such as stepping motors and ultrasonic motors, linear drive motors such as voice coil motors and moving magnet types can be used. When a rotary motor is used, the rotational motion is converted into a linear motion by a crank mechanism or the like to swing the lens 6. Which actuator is used may be determined in consideration of the recording speed, durability, recording position accuracy, and the like.
[0049]
  Further, which of the light source 5 and the lens 6 is swung depends on the configuration. As the light source 5 driven by the light source driving circuit 26, a light-emitting diode or a laser diode is generally used. This light source 5 is usually placed in a metal can. In this case, however, the light source 5 is heavy, and The lens 6 should be swung in consideration of the durability of the wiring connected to cause the light source 5 to emit light. Further, when a diode chip is used as the light source 5, the light source 5 is lighter than the lens 6, and therefore it is better to rock the light source 5 for high-speed response of rocking.
[0050]
  The basic configuration of the light beam recording apparatus P1 in the present embodiment is as described above. However, this light beam recording apparatus P1 mainly has the purpose of creating a printing plate or a block, so It is essential to realize high-density and high-precision recording. In order to obtain positional accuracy in the rotation direction of the drum 2, the configuration of the drive system of the drum 2 is an important factor. If the configuration is complicated, errors between components may accumulate and cause a decrease in accuracy. Therefore, it is desirable that the drive system has a simple configuration. Therefore, as described above, the drum shaft 15 that rotates integrally with the drum 2 and the output shaft 17 of the motor 3 are coaxially connected by the joint 18 to shorten the power transmission path and reduce the number of power transmission components. With this simple configuration, the rotation unevenness due to the accuracy error of the parts can be reduced as much as possible.
[0051]
  Further, when a motor 3 such as a stepping motor or a servo motor is used as a driving source of the drum 2, these motors 3 are excellent in position reproducibility when they are rotated once, and no accumulated positional deviation occurs regardless of how many times they are rotated. Therefore, even if a positional deviation occurs due to an error in the motor step angle, an eccentricity of the drum 2 or a rotational deflection, the motor 3 and the drum 2 are connected on the same axis, so that the deviation is always reproduced. It becomes. For this reason, the recording medium 1 is always set at a predetermined position on the drum 2 by the clamps 14 on the drum 2. Therefore, even when a four-color block composition necessary for color printing is created, the recording medium 1 is used. Since no misregistration occurs between the plates, a color image without color misregistration can be obtained. The drive control system for the stepping motor 3 may be a motor control system using a rotary encoder, although it is expensive.
[0052]
  When the motor 3 is attached to the housing 16, in general, an attachment structure in which the motor 3 is attached to the housing 16 via a grommet or a vibration isolating rubber is often employed for noise suppression and vibration isolation. However, by doing so, the motor 3 itself floats from the casing 16, and therefore there is a possibility that the position reproducibility of the rotation of the drum 2 varies. However, in the present embodiment, as shown in FIGS. 1 and 7, the motor 3 is attached to the high-rigidity housing 16 via the motor bracket 27 without interposing an elastic member such as a grommet or a vibration isolating rubber. Since it is attached, the motor 3 can be firmly fixed to the housing 16. Thereby, variation in the reproducibility of the rotational position of the drum 2 can be suppressed.
[0053]
  When there is a backlash between the drum shaft 15 and the output shaft 17 and the joint 18, when the weight balance of the drum 2 is unbalanced or external vibration is applied, the normal joint 18 is disengaged. As a result, drastic rotation unevenness of the drum 2 occurs. As a countermeasure, in this embodiment, a backlashless joint 18 that does not have play in the rotation direction with respect to the drum shaft 15 and the output shaft 17 is used. There are many types of backlashless joints 18, but high-rigidity joints are desirable. Rubber materials are inappropriate here, but for example, slit-type and disk-type joints also vary in rigidity. Of course, the higher the rigidity, the better, but the slit type or the disk type can be used as long as it is of a level that does not cause any problems when actually used. The rigid type is the most rigid, but if there is any eccentricity in mounting, it will cause vibration, so when mounting it will be mounted with a corresponding accuracy.
[0054]
  By the way, in the system in which the motor 3 and the drum 2 are directly connected, the rotational resolution of the drum 2 matches the resolution of the motor 3. Further, the torque of the rotational load of the drum 2 is the load applied to the motor 3. In order to increase the rotational resolution of the drum 2 or reduce the load on the motor 3, it is necessary to decelerate the rotation of the motor 3. Therefore, in the present embodiment, as shown in FIG. 8, the output shaft 17 of the motor 3 and the joint 18 are connected by a speed reducer 28. A reduction gear 28 having high accuracy and no backlash is commercially available. Since the reduction ratio of the speed reducer 28 is almost an integral multiple, the error in the step angle of the motor 3 does not affect the reproducibility of the position in the rotational direction when the drum 2 makes one rotation. Since the rotational resolution can be increased, high-density and high-precision drum driving can be performed.
[0055]
  In the light beam recording apparatus P1 in the present embodiment, the rotation direction of the drum 2 is the sub-scanning direction, and the main scanning direction is the axial direction of the drum 2, that is, the relative swinging direction of the light source 5 and the lens 6. . Therefore, when the lens 6 is swung in one direction while the drum 2 holding the recording medium 1 is stopped, the beam from the light source 5 is scanned along the axial direction of the drum 2. Next, when the drum 2 is rotated by one pitch and stopped, and the lens 6 is swung in the reverse direction, the beam is scanned along the axial direction of the drum 2. This operation is repeated a desired number of times. The beam scanning progress at this time is as shown by a solid line 29 in FIG. The arrow attached to the solid line 29 is the beam scanning direction. Information can be recorded in the two-dimensional area of the recording medium 1 by such scanning. The beam scanning area 30 at this time is the product of the length of one revolution of the drum 2 (length in the sub-scanning direction) and the swinging length of the lens 6 (length in the main scanning direction).
[0056]
  By the way, when the oscillation width of the lens 6 is increased to a certain value or more, the shape of the beam spot changes in an optical system and the light amount of the light source 5 is lost toward the both ends of the beam scanning length due to the oscillation. There is a concern that the recorded dots may be distorted or the recording density may be decreased due to the increase in the recording density. This is shown in FIG. In FIG. 10, the scanning region 30 of the beam is shown by cross-hatching, but a region with a low linear density shows a region where the dot distortion or the recording density is lowered.
[0057]
  Therefore, the optical head scanning means 31 (FIGS. 1 and 11) scans the entire optical head 8 along the axial direction (main scanning direction X) of the drum 2 so that clear information recording can be performed in a wide range in the beam scanning direction. Through FIG. 14). The optical head scanning unit 31 reciprocally drives the optical head 8 along the guide 32 by a driving force of a rotary motor converted into a linear motion or a driving force of a linear motor. The optical head scanning unit 31 includes a scanning position detection unit 33 that detects the position of the optical head 8 in the main scanning direction X, and a home that detects a state in which the optical head 8 has reached a home position that is one end in the main scanning direction. And a position sensor 34. The scanning position detection unit 33 includes a reflective or transmissive optical sensor (not shown) provided in the optical head 8 and a linear encoder 35 arranged in parallel with the guide 32. The scanning speed of the optical head 8 by the optical head scanning unit 31 does not need to be as high as that of the swing mechanism 25.
[0058]
  Therefore, as described with reference to FIG. 9, the lens 6 is swung in one direction while the drum 2 holding the recording medium 1 is stopped, and the beam from the light source 5 is moved along the axial direction of the drum 2. Next, with the drum 2 rotated by one pitch and stopped, the lens 6 is swung in the reverse direction to scan the beam along the axial direction of the drum 2. Repeat while lap. Note that the scanning length of the beam due to the swing of the lens 6 at this time is in a range in which no abnormality occurs in the shape of the beam spot and the optical density. By doing so, as shown in FIG. 12, the first round of information is recorded at one end of the recording medium 1. Thereafter, the optical head scanning unit 31 moves the optical head 8 by a desired length in the main scanning direction, and in this state, information is recorded on the recording medium 1 by the operation of the second round of the drum. The procedure for recording information after the second round of the drum 2 is the same as the information recording for the first round of the drum 2 described above. Since the optical head 8 can be moved in the main scanning direction X in this way, a recording area free from density unevenness can be expanded in the main scanning direction.
[0059]
  Thus, when the optical head 8 is scanned in the next region adjacent to the main scanning direction X, the scanning length is a, and the main scanning direction is obtained by relatively swinging the light source 5 and the lens 6. If the scanning length of the X beam is b, and a <b, the recording areas overlap as much as ba−a = c as shown in FIG. The amount of oscillation of the lens 6 is wasted by the overlap. Therefore, by designing so that a> b, as shown in FIG. 14, the scanning length of the beam due to the oscillation of the lens 6 can be fully utilized, so that the recording efficiency is improved and the recording time is shortened. Energy saving can be realized.
[0060]
  As described above, when the optical head 8 is scanned in the main scanning direction X, the state where the optical head 8 has reached the home position can be recognized by the output of the home position sensor 34, and the optical head 8 is positioned at an arbitrary scanning position. Since the state to be detected can be detected by the scanning position detecting means 33, recording can always be started from the correct position in the main scanning direction.
[0061]
  Next, a second embodiment of the present invention will be described with reference to FIGS. The same parts as those in the above embodiment are denoted by the same reference numerals, and the description thereof is also omitted. 15 is a plan view showing the light beam recording apparatus, FIG. 16 is a side view showing the power transmission gear device, FIG. 17 is a side view showing another example of the power transmission gear device, and FIGS. 18 and 19 are power transmission gear devices. It is explanatory drawing which shows the meshing state of the teeth.
[0062]
  The light beam device P2 in the present embodiment is the same as that in the above embodiment except that the drum 2 and the motor 3 are connected by a power transmission gear device 36. The power transmission gear device 36 includes a power transmission gear 37 (37 a, 37 b) that is a driving gear that is fixed to the output shaft 17 of the motor 3 and a power transmission gear 38 that is a drum gear that is fixed to the drum shaft 15. (38a, 38b). The power transmission gears 37a and 37b have the same helical twisting direction but the same number of teeth and pitch circle. Similarly, the power transmission gears 38a and 38b have the same twisting direction, but the same number of teeth and pitch circle. The gear ratio of these power transmission gears 37 and 38 is N: 1 (N is a natural number). That is, the power transmission gear 38 that rotates integrally with the drum 2 is larger than the power transmission gear 37 that is directly connected to the motor 3. By meshing the power transmission gears 37 and 38 having such a gear ratio, the rotational speed of the motor 3 is reduced and transmitted to the drum 2, so that the rotational accuracy error of the motor 3 is reduced and the power is supplied to the drum 2. Will communicate. Thereby, the rotation unevenness of the drum 2 can be reduced. Further, when the drum 2 makes one rotation, the power transmission gears 37 and 38 are always meshed with the same teeth.
[0063]
  As shown in FIG. 17, when an intermediate gear (power transmission gear) 39 is engaged between the power transmission gear 37 and the power transmission gear 38, the gear ratio of the power transmission gears 37 and 38 is set to N as described above. 1 (N is a natural number), and the gear ratio between the power transmission gear 38 and the intermediate gear 39 may satisfy M: 1 (M is a natural number). If it does so, when the drum 2 makes one rotation, all the gears 37, 38, and 39 will mesh in the same position as the original.
[0064]
  The effect obtained by determining the gear ratio as described above can be obtained without particularly limiting the tooth profile of the gears 37, 38, 39. However, when the disturbance of the rotation of the drum 2 caused by noise or vibration is taken into consideration. The helical gear is desirable. This is because the helical gear has a higher meshing ratio than the spur gear, and therefore smooth driving can be realized, and the influence on the image such as gear eyes can be reduced.
[0065]
  Further, a plurality of these power transmission gears 37 and 38 are used on the same axis. Here, a state where two sheets are stacked will be described, but any number of sheets may be stacked. The plurality of power transmission gears 37 and 38 stacked on the same axis have a high rate of meshing with the teeth slightly shifted due to variations in the position in the rotational direction. For this reason, it becomes possible to raise the meshing rate as the power transmission gear device 36 as a whole. Therefore, it is advantageous from the viewpoint of noise and vibration. Further, when the gears 37 and 38 are used on the same axis, errors such as eccentricity and tooth thickness can be reduced as compared with the case where one gear 37 or 38 is used on the same axis.
[0066]
  18 and 19, (a) shows the meshing state of the power transmission gears 37a, 38a on the near side on the same axis, and (b) shows the meshing state of the power transmission gears 37b, 38b on the back side. As shown in FIG. 18, the backlash generation direction indicated by ● is the same in both the front side power transmission gears 37 a, 38 a and the back side power transmission gears 37 b, 38 b on the rotation direction delay side. In some cases, the backlash may appear as a positional deviation in the rotational direction between the motor 3 and the drum 2 as it is.
[0067]
  However, in the present embodiment, the two power transmission gears 37a and 37b or the power transmission gears 38a and 38b stacked on the same axis can be adjusted relative to each other in the rotational direction. It is configured. By doing so, the backlash of the meshing portion can be adjusted. As an example of the method for adjusting the position in the rotational direction, as shown in FIG. 19A, if the position where the backlash occurs at the meshing portion of the power transmission gears 37a, 38a on the coaxial side is the rotational direction delay side, As shown in FIG. 19 (b), the position where the backlash is generated at the meshing portion of the power transmission gears 37b, 38b on the back side on the same axis is set as the rotational advance side, so that the power transmission gear device 36 of virtually no backlash is provided. And the positional deviation in the rotational direction between the motor 3 and the drum 2 can be prevented.
[0068]
  By the way, when a helical gear is used as the power transmission gears 37 and 38, an axial force is generated in the motor 3 and the drum 2 by driving the gear. This axial force may impair the axial recording accuracy of the drum 2. Therefore, as shown in FIG. 15, the front side gears are determined by reversing the torsional directions of the two power transmission gears 37a and 37b and the power transmission gears 38a and 38b that are coaxially overlapped with each other. The force acting in the axial direction due to the meshing of 37a, 38a and the force acting in the axial direction due to the meshing of the rear gears 37b, 38b cancel each other, so that the force for displacing the drum 2 in the axial direction as a result. It becomes possible to make it smaller.
[0069]
  Furthermore, the power transmission gears 37a, 37b, 38a, 38b using helical gears are formed in a state where the twisting direction of the helical gears is changed. In other words, it is formed in a state where not all the twist directions of the halves match. Thereby, the thrust load generated as a component force due to the meshing of the power transmission gears 37a, 37b, 38a, 38b is suppressed. Accordingly, it is possible to prevent the movement of the drum 2 in the axial direction and reduce the variation in the information recording position in the axial direction.
[0070]
As described above, in the present embodiment, since the power transmission gear including the drum gear and the drive gear included in the power transmission gear device uses a helical gear, noise and vibration in the power transmission gear device are reduced. Thus, the rotation unevenness of the drum can be further suppressed.
[0071]
Further, in the present embodiment, the power transmission gear device meshes a plurality of power transmission gears that are coaxially overlapped with each other, so that noise and vibration in the power transmission gear device can be reduced, The effect of suppressing rotation unevenness can be further enhanced.
[0072]
Further, in the present embodiment, the plurality of power transmission gears stacked on the same axis are supported so that their fixed positions in the rotation direction can be adjusted with respect to each other, so that the meshing portion does not depend on the accuracy of the power transmission gear. The backlash can be eliminated.
[0073]
Further, in the present embodiment, since the power transmission gear using the helical gear has a non-uniform twisting direction of the helical gear, the thrust load generated as a component force due to the meshing of the power transmission gear is suppressed. As a result, the movement of the drum in the axial direction can be prevented, and variations in the information recording position in the axial direction can be reduced.
[0074]
  Next, a third embodiment of the present invention will be described with reference to FIGS. The same parts as those in the above embodiment are denoted by the same reference numerals, and the description thereof is also omitted. 20 is a plan view showing a light beam recording apparatus, FIGS. 21 and 22 are plan views showing the arrangement of a plurality of optical heads, and FIG. 23 is a beam shake caused by a relative swinging operation of a light source and a converging optical system. FIG. 24 is a front view showing a state in which optical heads are arranged in a staggered manner in a plurality of stages, FIG. 25 is a side view showing a state in which optical heads are arranged in a staggered manner in a plurality of stages, and FIG. It is a top view which shows an example of the recording pattern by the some optical head arranged in zigzag form.
[0075]
  The light beam device P3 in the present embodiment is characterized in that a plurality of optical heads 8 are arranged along the axial direction of the drum 2 (main scanning direction X). The configuration of each optical head 8 and other configurations are the same as those in the first embodiment. As a means for swinging the lens 6 of each optical head 8, the swing mechanism 25 shown in FIG. 6 may be used. However, as shown in FIG. 21, the lens 6 is swung in the main scanning direction X by applying a voltage. The piezoelectric element 25a to be moved may be used as the swinging means. Furthermore, as shown in FIG. 22, the structure of the swinging means is constructed by supporting all the lenses 6 by a common support member 40 and swinging the support member 40 by a set of piezoelectric elements 25a. This can contribute to simplification and downsizing.
[0076]
  According to such a configuration, all the optical heads 8 are driven simultaneously, and the two-dimensional recording medium 1 on the drum 2 is driven by the swinging motion of the lens 6 in the main scanning direction X and the rotating motion of the drum 2. Information can be recorded in the area. The procedure of information recording will be specifically described with reference to FIG. With the drum 2 holding the recording medium 1 stopped, the lenses 6 of all the optical heads 8 are swung in one direction to scan the beam from the light source 5 along the axial direction of the drum 2, and then With the drum 2 rotated by one pitch and stopped, the lenses 6 of all the optical heads 8 are swung in the reverse direction to scan the beam along the axial direction of the drum 2, and this operation is performed on the drum 2. Repeat while lap. As described above, since information can be recorded using the plurality of optical heads 8 along the main scanning direction X, the drums can be formed without making the swinging width of the lens 6 in each optical head 8 unnecessarily wide. The information recording area in the fine image state can be enlarged by the length of 2. Further, since a plurality of optical heads 8 can be driven simultaneously, the recording time can be shortened. By narrowing the arrangement pitch of the optical heads 8 and arranging more optical heads 8, the recording time can be further shortened.
[0077]
  When the optical heads 8 are arranged in a line, there is a limit to narrowing the arrangement pitch in the main scanning direction X. Therefore, as shown in FIG. 24, a plurality of optical heads 8 are arranged in a staggered pattern in two rows in the axial direction of the drum 2 (main scanning direction X). Although only the lens 6 is shown in FIG. 24, the light sources 5 facing the lens 6 are arranged in a direction perpendicular to the paper surface. By arranging the optical heads 8 in this way, the width of scanning the beam by one optical head 8 can be half of the width of the optical head 8 itself, so that further high-speed recording is possible. Further, since the swinging width of the lens 6 can be narrowed, the beam spot shape can be maintained in a desired shape, and further high image quality recording is possible. Needless to say, by increasing the number of rows of the optical heads 8 to 3 rows and 4 rows, higher speed recording and higher image quality recording are possible.
[0078]
  Even if the optical heads 8 are arranged in a plurality of rows along the axis of the drum 2, the recording position by the optical head 8 may not be on the drum 2 for each row depending on how the optical head 8 is supported. In this case, the recording position of the optical head 8 may be relatively shifted due to the influence of eccentricity of the drum 2 and rotation unevenness. This is shown in FIG. In FIG. 26, reference numeral 41 denotes a recording area by the optical head 8 arranged in the upper or lower row, and reference numeral 42 denotes a recording area by the optical head 8 arranged in the lower or upper row.
[0079]
  Therefore, in the present embodiment, the optical head 8 is supported so that the recording positions of the optical head 8 are aligned in a line along the axis of the drum 2. Specifically, as shown in FIG. 25, the optical heads 8 arranged in the upper row are supported so that the beam is inclined downward as the direction of the beam is directed to the drum 2, and the optical heads 8 arranged in the lower row are The beam is supported so as to be tilted upward as it goes to the drum 2. Therefore, since the influence of eccentricity and rotation unevenness of the drum 2 acts on all the optical heads 8 in the same manner, it is possible to prevent the relative displacement of the recording position between the optical heads 8.
[0080]
  Next, a fourth embodiment of the present invention will be described with reference to FIG. The same parts as those in the above embodiment are denoted by the same reference numerals, and the description thereof is also omitted. FIG. 27 is a plan view showing the light beam recording apparatus.
[0081]
  The light beam device P4 in the present embodiment has a configuration in which the drum 2 and the motor 3 are connected by a power transmission gear device 36, and a plurality of optical heads 8 are arranged along the axial direction of the drum 2 (main scanning direction X). There is a feature in the point.
[0082]
  The detailed configuration of the power transmission gear device 36 and the operational effects of the configuration are the same as those of the second embodiment described with reference to FIGS. Further, the configuration in which a plurality of optical heads 8 are arranged along the axial direction of the drum 2 and the operational effects of the configuration are the same as those in the third embodiment described with reference to FIGS.
[0083]
【The invention's effect】
  According to the first aspect of the present invention, an optical head having a light source and a converging optical system for converging a beam emitted from the light source onto a recording medium on the drum, and at least one of the light source and the converging optical system is recorded on the recording medium. Oscillating means that oscillates relatively along the surface, a drive source that is coaxially connected to the drum and rotationally drives the drum,Optical head scanning means for driving the optical head to reciprocate along the axial direction of the drum;Therefore, information can be recorded in the two-dimensional area of the recording medium on the drum by the relative swinging operation of the light source and the converging optical system and the rotating operation of the drum. In this case, by connecting the drum coaxially to the drive source, it is possible to reduce the number of rotation transmitting members and suppress the rotation unevenness of the drum. Therefore, a polygon mirror, an fθ lens, etc. are required as in the prior art. Instead, precise information recording can be performed using a low-cost optical head that simply swings the light source and the converging optical system relatively.
Further, by scanning the optical head, an information recording area free from distortion and density unevenness in the axial direction of the drum can be expanded.
[0084]
  According to a second aspect of the present invention, an optical head having a light source and a converging optical system for converging a beam emitted from the light source onto a recording medium on a drum, and at least one of the light source and the converging optical system is recorded on the recording medium. Oscillating means for relatively oscillating along the surface, a drive source for rotationally driving the drum, a power transmission gear device for connecting the drum and the drive source at a gear ratio of N (natural number): 1,Optical head scanning means for driving the optical head to reciprocate along the axial direction of the drum;Therefore, information can be recorded in the two-dimensional area of the recording medium on the drum by the relative swinging operation of the light source and the converging optical system and the rotating operation of the drum. In this case, by connecting the drum to the drive source at a gear ratio of N: 1, the rotation irregularity of the drum and the positional deviation in the rotation direction of the drum can be suppressed. Therefore, precise information recording can be performed using a low-cost optical head that simply swings the light source and the converging optical system relative to each other.
Further, by scanning the optical head, an information recording area free from distortion and density unevenness in the axial direction of the drum can be expanded.
[0085]
  Claim3The described invention is claimed.1 or 2In the described invention, a stepping motor or a servo motor is used as the drive source, so that the profile of the beam irradiation position in the drum rotation direction can be made reproducible, thereby enabling a full color image. This can contribute to prevention of color misregistration during formation.
[0086]
  Claim4The invention described in claim 1 to claim 13In the invention according to any one of the above, since the drive source is supported by the high-rigidity member without interposing an elastic member having a silencing property, the drive source can be firmly fixed. Variations in the reproducibility of the rotational position can be suppressed.
[0087]
  Claim5The described invention is claimed.1In the described invention, since the drum and the driving source are connected to the drum and the output shaft of the driving source by a joint having no play in the rotational direction, vibration from the outside is generated when the weight of the drum is unbalanced. It is possible to suppress the occurrence of uneven rotation of the drum due to the case of receiving it, and thereby the influence on the recording position accuracy can be suppressed to the minimum.
[0088]
  Claim6The described invention is claimed.1In the described invention, since the drum and the drive source are connected by a speed reducer, the rotational resolution of the drum can be increased, and thereby the recording density can be improved.
[0089]
  Claim7The described invention is claimed.Any one of 1-6In the described invention, the swinging direction for relatively swinging the light source and the converging optical system is set to a direction equal to the scanning direction of the optical head. Therefore, by scanning the optical head, the axial direction of the drum The information recording area can be enlarged.
[0090]
  Claim8The described invention is claimed.7In the described invention, the scanning length of the optical head is determined to be longer than the scanning length of the beam obtained by relatively swinging the light source and the converging optical system. As the scanning length of the beam by relatively rocking becomes longer, the beam spot at the end of the scanning length is distorted and the optical density is reduced. By scanning the entire optical head, the drum The information recording area free from distortion and density unevenness in the axial direction can be enlarged.
[0091]
  Claim9The described invention is claimed.1 to 8In the invention described in any one of the above, since the optical head scanning means includes scanning position detection means for detecting the position of the optical head in the scanning direction, the optical head is moved to a desired position while detecting the position of the optical head. Thus, information can be accurately recorded at a desired position.
[0092]
  Claim10In the invention described in claim 2, since the power transmission gear device directly meshes the drum gear fixed to the drum and the drive gear fixed to the drive source, the followability of the drum to the drive source Can be improved, and uneven rotation of the drum can be further suppressed.
[0093]
  Claim11The described invention is claimed.1In the described invention,in frontThe recording head is along the axial direction of the drum.MultipleSince they are arranged, it becomes easy to align information recording positions in a line along the axial direction of the drum.
Further, since information can be recorded using a plurality of optical heads along the axial direction of the drum, the information recording area in the axial direction of the drum can be expanded. In this case, by connecting the drum coaxially to the drive source, it is possible to reduce the number of rotation transmitting members and suppress the rotation unevenness of the drum. Therefore, a polygon mirror, an fθ lens, etc. are required as in the prior art. Instead, precise information recording can be performed using a low-cost optical head that simply swings the light source and the converging optical system relatively.
[0094]
  Claim12The described invention is claimed.11In the described invention, the plurality of optical heads are arranged in a zigzag manner in two or more rows along the axial direction of the drum, so that information recording can be performed at high speed.
[0095]
  Claim13The described invention is claimed.12In the described invention, since all the optical heads are supported so that the recording positions are aligned on a single straight line along the axial direction of the drum, it is possible to increase the density of information recorded in the line direction. it can.
[0096]
  Claim14The described invention is claimed.Any one of 11-13In the described invention, since the converging optical systems or light sources of the optical heads are supported by a common support member, the converging optical systems or light sources of all the optical heads are supported by a single supporting member by one swinging unit. At the same time, it can be swung together. Thereby, simplification and size reduction of a structure of a rocking | swiveling means can be achieved.
[Brief description of the drawings]
FIG. 1 is a plan view showing a light beam recording apparatus according to a first embodiment of the present invention.
FIG. 2 is a side view thereof.
FIG. 3 is an explanatory diagram showing a sequence of a rewritable recording medium.
FIG. 4 is a cross-sectional view of a drum.
FIG. 5 is a vertical side view showing another example of a paper feeding device provided in the light beam device.
FIG. 6 is an explanatory diagram showing beam deflection caused by relative oscillation between a light source and a converging optical system.
FIG. 7 is a partial plan view showing a connection structure between a drum and a drive source.
FIG. 8 is a partial plan view showing a modified example of the connection structure between the drum and the drive source.
FIG. 9 is an explanatory diagram illustrating a beam scanning state with respect to a recording medium.
FIG. 10 is an explanatory diagram illustrating a beam scanning state with respect to a recording medium.
FIG. 11 is a plan view showing an optical head scanning unit.
FIG. 12 is an explanatory diagram illustrating a beam scanning state with respect to a recording medium.
FIG. 13 is an explanatory diagram illustrating a beam scanning state with respect to a recording medium.
FIG. 14 is an explanatory diagram illustrating a beam scanning state with respect to a recording medium.
FIG. 15 is a plan view showing a light beam recording apparatus in a second embodiment of the present invention.
FIG. 16 is a side view showing a power transmission gear device.
FIG. 17 is a side view showing another example of the power transmission gear device.
FIG. 18 is an explanatory diagram showing a state of meshing teeth of the power transmission gear device.
FIG. 19 is an explanatory view showing a meshing state of teeth of the power transmission gear device.
FIG. 20 is a plan view showing a light beam recording apparatus according to a third embodiment of the present invention.
FIG. 21 is a plan view showing an arrangement state of a plurality of optical heads.
FIG. 22 is a plan view showing an arrangement state of a plurality of optical heads.
FIG. 23 is an explanatory diagram showing beam deflection caused by relative oscillation between the light source and the converging optical system.
FIG. 24 is a front view showing a state in which optical heads are arranged in a staggered manner in a plurality of stages.
FIG. 25 is a side view showing a state in which optical heads are arranged in a staggered manner in a plurality of stages.
FIG. 26 is a plan view showing an example of a recording pattern by a plurality of optical heads arranged in a plurality of staggered patterns.
FIG. 27 is a plan view showing a light beam recording apparatus according to a fourth embodiment of the present invention.
[Explanation of symbols]
  1 Recording medium
  2 drums
  3 Drive source, stepping motor, servo motor
  5 Light source
  6 Convergent optics
  8 Optical head
  16 High rigidity member
  18 joints
  25, 25a rocking means
  28 Reducer
  31 Optical head scanning means
  33 Scanning position detection means
  36 Power transmission gear device
  37 Power transmission gear, drive gear
  38 Power transmission gear, drum gear
  39 Power transmission gear
  40 Support member

Claims (14)

A drum for holding a recording medium;
An optical head having a light source and a converging optical system for converging a beam emitted from the light source onto the recording medium on the drum;
Rocking means for relatively rocking at least one of the light source and the converging optical system along the recording surface of the recording medium;
A drive source that is coaxially connected to the drum and rotationally drives the drum;
An optical beam recording apparatus comprising: an optical head scanning unit that drives the optical head to reciprocate along the axial direction of the drum . A drum for holding a recording medium;
An optical head having a light source and a converging optical system for converging a beam emitted from the light source onto the recording medium on the drum;
Rocking means for relatively rocking at least one of the light source and the converging optical system along the recording surface of the recording medium;
A drive source for rotationally driving the drum;
A power transmission gear device for connecting the drum and the drive source at a gear ratio of N (natural number): 1;
An optical beam recording apparatus comprising: an optical head scanning unit that drives the optical head to reciprocate along the axial direction of the drum . 3. The light beam recording apparatus according to claim 1, wherein a stepping motor or a servo motor is used as the driving source. The driving source is a light beam recording apparatus as claimed in claims 1 and is supported by the highly rigid member without interposing an elastic member 3 having a sound deadening qualities. Optical beam recording apparatus of the drum and the driving source the drum and the driving source of the rotational direction of the play linked to that claim 1, wherein the no joints to the output shaft and. Light beam recording device according to claim 1, wherein are coupled by a reduction gear and the driving source and the drum. Swinging direction for relatively swinging the said converging optical system and the light source, a light beam recording device according to any one of claims 1 to 6 is defined in a direction equal to the scanning direction of the optical head. 8. The optical beam recording apparatus according to claim 7 , wherein a scanning length of the optical head is set longer than a scanning length of a beam obtained by relatively swinging the light source and the converging optical system. The optical head scanning means, light beam recording device according to any one of claims 1 to 8 comprising the scanning position detecting means for detecting a scanning position of the optical head.   3. The light beam recording apparatus according to claim 2, wherein the power transmission gear device directly meshes a drum gear fixed to the drum and a drive gear fixed to the drive source. Before SL optical head, a light beam recording device according to claim 1, characterized in that a plurality arranged along the axial direction of the drum. The light beam recording apparatus according to claim 11 , wherein the plurality of optical heads are arranged in a staggered manner over two or more rows along the axial direction of the drum. 13. The light beam recording apparatus according to claim 12 , wherein all the optical heads are supported so that the recording positions are aligned on a single straight line along the axial direction of the drum. 14. The light beam recording apparatus according to claim 11, wherein the converging optical systems or the light sources included in the optical heads are supported by a common support member.

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