Patent Application
20070268356
The accompanying drawings, which are incorporated in and comprise a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.
Now, embodiments of the present invention will be described with reference to the accompanying drawings.
First, a first embodiment in which a pair of a laser emission section and an LED emission section is arranged will be described.
The collimator 2 converts the laser beam as the divergent light into parallel luminous fluxes. The laser emission section 1 has a high calorific power. Thus, the laser emission section 1 is fixed to a heat slinger so as to radiate generated heat.
The polygon mirror 3 is driven to rotate by a polygon motor described later.
The laser beam from the laser emission section 1 is converted into a light beam used for writing information. The light beam scans a thermosensitive medium 4 being transported in the direction of an arrow in the figure in a main scanning direction perpendicular to the transport direction (sub-scanning direction) by the rotations of the polygon mirror 3. The polygon mirror 3 is arranged so that the rotational axis thereof may be parallel to the sub-scanning direction as the transport direction of the thermosensitive medium 4. In addition, if a folded mirror or a prism is used along the path, the rotational axis of the polygon mirror 3 may not be parallel to the sub-scanning direction due to the effect of a reflection surface angle.
For the laser beam emitted from the laser emission section 1 via the collimator 2 to the reflection surface of the polygon mirror 3, the center optical axis of the incoming light beam becomes perpendicular to the rotational axis of the polygon mirror 3. The laser beam reflected by the polygon mirror 3 is reflected as a light beam at a predetermined timing by a folded mirror 5 to come into a writing position sensor 6.
The recording apparatus is provided with an LED emission section 7 as a second light source in which a plurality of light-emitting diodes (LEDs) are arranged in the main scanning direction. The LED emission section 7 is arranged, as shown in
In
The CPU 11 composes a main unit of the control section. In the ROM 12, there is stored a program required for the CPU 11 to control the various components of the recording apparatus. In the RAM 13, there are provided a memory area used for performing operations and data processing and a memory area used for temporarily storing data. The input/output port 14 controls the inputs and outputs to/from the various components connected externally.
An operating section 16, a laser control section 17, a motor control section 19, a sensor control section 20, an LED control section 21 and a motor control section 23 are connected to the input/output port 14. A keyboard and a display are arranged in the operating section 16. The laser control section 17 controls the laser emission section 1. The motor control section 19 controls a polygon motor 18. The polygon mirror 3 is driven to rotate by the polygon motor 18. The sensor control section 20 controls the writing position sensor 6. The LED control section 21 controls the LED emission section 7. The motor control section 23 controls a paper feed motor 22. The thermosensitive medium 4 is transported by the paper feed motor 22.
The thermosensitive medium 4 uses a rewritable medium which has a photothermal conversion layer having a light wavelength absorption property and a coloring layer colored and decolored by the heat generated by the photothermal conversion layer. The absorption property of the photothermal conversion layer accords, as shown in
It depends on the heat generation temperature of the photothermal conversion layer whether the coloring layer is colored or decolored. According to the present embodiment, in a state in which information is written in the thermosensitive medium 4 by coloring the coloring layer, for example, when the laser emission section 1 of the first light source is stopped and the output of the LED emission section 7 as the second light source is slightly raised, the coloring layer is decolored thereby to erase information.
For the thermosensitive medium 4, the absorption property of the photothermal conversion layer accords at the peak position thereof with the wavelength λ1 of the laser beam from the laser emission section 1, enabling the efficiency of the photothermal conversion by the photothermal conversion layer to be improved. Moreover, since the peak position of the absorption property of the photothermal conversion layer lies outside an optical wavelength, the thermosensitive medium 4 is seldom heat-sensitized to usual illuminations. Therefore, the thermosensitive medium 4 can be prevented from being deteriorated.
In such a configuration, the laser beam L1 from the laser emission section 1 scans the thermosensitive medium 4 being transported in the main scanning direction by the rotations of the polygon mirror 3. By this scanning, as shown in
By irradiating with the LED light beam L2, the scanning range of the laser beam L1 is heated. The laser beam L1 scans this heated line-like range virtually simultaneously. The operating timings of the laser emission section 1 and the LED emission section 7 at this time are shown in
First, a writing position detection signal is output from the writing position sensor 6. Subsequently, the respective LEDs of the LED emission section 7 emit lights sequentially for a certain period of time to sequentially preheat the scanning line of the laser beam. The laser beam from the laser emission section 1 turns the laser beam on or off in the printing range based on the bit data of “1” or “0” in the recorded information. This laser beam is turned on or off with chasing the preheated portions by the respective LED light beams for scanning. When the laser beam is turned on, the laser beam L1 is irradiated to the photothermal conversion layer.
In this operation, the photothermal conversion layer of the thermosensitive medium 4 is, as shown in
As described above, after preheated to the temperature T2 by the LED light beam L2 from the LED emission section 7, the thermosensitive medium 4 is heated by the laser beam L1 from the laser emission section 1 thereby to be colored. Accordingly, the laser emission section 1 need not have a high output, and a commercially available semiconductor laser having an output on the order of several watts may be used. In addition, the irradiation time of the laser beam L1 required for recording dots can be shortened sufficiently.
Accordingly, an economically more efficient and down-sized recording apparatus can be provided. In addition, the same printing speed as that of a line thermal head heating one line simultaneously to make prints can be ensured to realize a sufficient recording speed. Moreover, in contrast to the line thermal head, no information is recorded by coming into contact with the thermosensitive medium 4, being very advantageous to a rewritable medium in which the thermosensitive medium 4 repeats recording and erasing many times.
In the first embodiment, the recording operation of the thermosensitive medium 4 is not limited to the above. For example, as shown in
First, all the LEDs of the LED emission section 7 emit lights to preheat the vicinity of the scanning line of the laser beam. Next, a writing position detection signal is output from the writing position sensor 6. Subsequently, the laser beam L1 from the laser emission section 1 scans the scanning line. Then, the laser beam is turned on or off in the printing range based on the bit data of “1” or “0” in the recorded information. When the laser beam is turned on, dots are recorded.
As described above, also by controlling the laser emission section 1 and the LED emission section 7, similar effects and advantages can be obtained.
Now, a second embodiment in which a plurality of pairs of laser emission sections and LED emission sections are arranged will be described.
The arrangement pitch P0 of the respective laser emission sections 31 to 35 is a printing pitch P1 as it is in the transport direction of the thermosensitive medium 4, that is, in the sub-scanning direction. In addition, the printing pitch can be changed by using an optical fiber bundle or by changing the angle of the reflection surface of the polygon mirror.
The respective laser emission sections 31 to 35 have a high calorific power. Thus, the respective laser emission sections 31 to 35 are fixed to a heat slinger so as to radiate generated heat.
The polygon mirror 36 has a rotational axis and a long reflection surface parallel to the sub-scanning direction as the transport direction of the thermosensitive medium 4. The polygon mirror 36 is driven to rotate by a polygon motor. In addition, if a folded mirror or a prism is used along the path, the rotational axis of the polygon mirror 3 may not be parallel to the sub-scanning direction due to the effect of a reflection surface angle.
The laser beams from the respective laser emission sections 31 to 35 are reflected by the same reflection surface of the polygon mirror 36. For the laser beams emitted from the respective laser emission sections 31 to 35 to the reflection surface of the polygon mirror 36, the center optical axes of the incoming light beams become perpendicular to the rotational axis of the polygon mirror 36.
In the recording apparatus, there are provided, as a second light source, five LED emission sections 37, 38, 39, 310 and 311 in each of which a plurality of light-emitting diodes (LEDs) are arranged. The respective LED emission sections 37, 38, 39, 310 and 311 are arranged with a predetermined pitch in the transport direction of the thermosensitive medium 4, corresponding to the respective laser emission sections 31 to 35.
The respective LED emission sections 37 to 311 are arranged at a low position above the thermosensitive medium 4 so that the lights from the respective LEDs may be irradiated directly to the thermosensitive medium 4. The respective LED emission sections 37 to 311 irradiate the lights to be irradiated so that the lights to be irradiated may be superimposed on the laser beams from the respective laser emission sections 31 to 35 on the scanning lines. Alternatively, the respective LED emission sections 37 to 311 irradiate the lights to be irradiated to the vicinity of the scanning lines of the laser beams prior to the scanning lines of the laser beams.
In
In
In the recording apparatus, the arrangement pitch P0 of the respective laser emission sections 31 to 35 is a printing pitch P1 as it is in the sub-scanning direction of the thermosensitive medium 4. Thus, dots can be recorded simultaneously by five lines in the thermosensitive medium 4 in the main scanning direction thereof. When the scanning of one line is completed, the thermosensitive medium 4 is transported by a distance five times as large as the printing pitch P1. Moreover, after transportation, one line is scanned again by the respective laser emission sections 31 to 35 thereby to record dots. By repeating this, high-speed printing can be performed on the thermosensitive medium 4.
In the recording apparatus of the present embodiment, the arrangement pitch between the respective laser emission sections 31 to 35 may be set to four times as large as the printing pitch P1. In this case, as shown in
On the other hand, if the thermosensitive medium 4 is longer than twenty times of the printing pitch P1, the thermosensitive medium 4 is transported by a distance twenty times as large as the printing pitch P1 to record dots of four lines with a pitch four times as large as the printing pitch P1 by the respective laser emission sections 31 to 35. In this manner, printing can be performed simultaneously on five lines, thereby realizing high-speed printing.
As described above, also in the second embodiment, the recording apparatus can realize a sufficient recording speed. Moreover, the thermosensitive medium 4 is preheated by the LED light beams and is rapidly heated and cooled by the laser beams, thereby ensuring a reliable recording even if the laser emission section 1 has a relatively low output. Accordingly, an economically more efficient and down-sized recording apparatus can be provided.
In the second embodiment, five laser emission sections and five LED emission sections are arranged, and however, the number of the laser and LED emission sections is not limited to the above number.
In the first and second embodiments, the wavelength λ1 of the laser beam from the laser emission section and the wavelength λ2 of the lights from the LED emission section are set substantially equal to each other, and however, the wavelength λ1 and the wavelength λ2 may be different from each other. For example, as shown in
Moreover, a rewritable medium having a photothermal conversion layer of which peak positions of the absorption property accord with the wavelengths λ1 and λ2 need not be necessarily used. The absorption property of the photothermal conversion layer exhibits, as shown in the curve G1 and the curve G2 of
However, as shown in
In the first and second embodiments, a rewritable medium capable of coloring and decoloring is used as the thermosensitive medium, and however, a thermosensitive medium only for coloring may be used.
In the first and second embodiments, a semiconductor laser is used as the first light source, and however, the first light source is not limited thereto. Similarly, a LED is used as the second light source, and however, the second light source is not limited thereto. For example, a semiconductor laser may be used as the second light source.
One configurational example in which semiconductor lasers are used as the second light source 7 is shown in
The laser emission areas 61 to 6n of the semiconductor lasers 41 to 4n are longer in the direction of the p-n bonding surfaces 51 to 5n than the laser emission areas of a single-mode type semiconductor laser respectively. For example, the laser emission areas 61 to 6n are, for example, 50 to 200 μm long in the direction of the p-n bonding surfaces 51 to 5n in the multi-mode type semiconductor lasers 41 to 4n. This is, for example, by 3 μm longer than the laser emission areas 61 to 6n of a single-mode type semiconductor layer respectively. Thereby, the semiconductor laser beams 71 to 7n output from the multi-mode type semiconductor lasers 41 to 4n exhibit a property of being difficult to narrow down in the same direction as in the directions of the p-n bonding surfaces 51 to 5n when converted into images by optical axis object type lenses.
A plurality of collimator lenses (imaging lenses) 81 to 8n are provided on the optical path of the semiconductor laser beams 71 to 7n output from the semiconductor lasers 41 to 4n. The collimator lenses 81 to 8n exhibit a property of narrowing down the semiconductor laser beams 71 to 7n in a direction perpendicular to the directions f of the p-n bonding surfaces 51 to 5n and of being difficult to narrow down the semiconductor laser beams 71 to 7n in the same direction as in the directions f of the p-n bonding surfaces 51 to 5n. The semiconductors 41 to 4n are provided so that the directions f of the p-n bonding surfaces 51 to 5n may coincide with one another. In addition, actually the semiconductor lasers 41 to 4n are used as laser chips respectively.
The collimator lenses 81 to 8n convert the semiconductor laser beams 71 to 7n into images on the recording surface of the thermosensitive medium 4 respectively. These collimator lenses 81 to 8n are not anamorphic, but optical axis symmetrical.
A plurality of cylindrical lenses (anamorphic lenses) 91 to 9n as an intensity equalization optical system are provided on the optical path of the semiconductor laser beams 71 to 7n converted into images by the collimator lenses 81 to 8n respectively. These cylindrical lenses 91 to 9n are provided on the optical path of the semiconductor laser beams 71 to 7n output from semiconductor lasers 41 to 4n respectively. These cylindrical lenses 91 to 9n exert a refraction output in the arrangement directions of the semiconductor lasers 41 to 4n respectively. Nevertheless, these cylindrical lenses 91 to 9n superimpose parts of the semiconductor laser beams 71 to 7n converted into images on the recording surface of the thermosensitive medium 4 by the collimator lenses 81 to 8n, that is, the end portions of the semiconductor laser beams 71 to 7n in the same direction as the directions f of the p-n bonding surfaces 51 to 5n on one another, respectively, thereby defocusing the semiconductor laser beams 71 to 7n in the directions f of the p-n bonding surfaces 51 to 5n to equalize the intensity distribution on the recording surface of the thermosensitive medium 4 by the semiconductor laser beams 71 to 7n in the directions f of the p-n bonding surfaces 51 to 5n in the semiconductor lasers 41 to 4n, in other words, in the arrangement directions of the semiconductor lasers 41 to 4n.
Another configurational example in which semiconductor lasers are used as the second light source 7 is shown in
Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2006-140367 | May 2006 | JP | national |
| 2007-062848 | Mar 2007 | JP | national |
