JP2007206432A - Printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer designed to reduce power consumption. <P>SOLUTION: Upon the depression of a print SW, image data is read from SDRAM, and the maximum density of an R image is detected. An amount Treq of exposure required to reproduce it is obtained with reference to a lookup table. Also, a drive voltage Vreq required for an LED corresponding to the required amount Treq of exposure is obtained with reference to the characteristic curve P of the R image. The LED is driven by the required drive voltage Vreq, one line of image data is read. The opening time of each shutter of a liquid crystal shutter array is adjusted. The one line of the R image is recorded on an instant film as a latent image. After a G image and a B image are recorded on the same line in the similar manner, the instant film is conveyed in step corresponding to one line. After images are recorded on all the lines as latent images, the instant film is ejected out while developer is spread inside. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a printer, and more particularly to a printer that records an image on a recording medium such as an instant film.

  There is known a photographic printer that displays an image on a liquid crystal panel, irradiates light from a light source on the liquid crystal panel, and exposes the image onto a photosensitive material (printing paper) that is a recording medium by transmitted light transmitted through the liquid crystal panel. (Patent Document 1). Also, there is known a recording medium that uses an instant film and records an image as a latent image on the instant film using an optical head (for example, Patent Document 2).

The optical head includes light emitting elements (LEDs) having emission colors of red (R), green (G), and blue (B) as light sources, and each of R, G, and B sequentially emitted by these light emitting elements. Light is guided through a light guide to a liquid crystal shutter array extending in the main scanning direction of the instant film. The R, G, and B lights are sequentially imaged on the instant film after being adjusted to light amounts corresponding to the gradation of the image by the shutters of the liquid crystal shutter array. Thereby, a latent image of a color image is recorded.
JP-A-9-101578 Japanese Patent Laid-Open No. 2005-17577

  Since the light-emitting element is always turned on with the maximum light amount, particularly when the printer is used for mobile use, there is a problem that the power source battery is consumed very much and the number of printable sheets is reduced.

  SUMMARY An advantage of some aspects of the invention is that it provides a printer that reduces power consumption.

  The printer according to the present invention is a printer that records an image on a recording medium as a latent image by performing exposure according to image data on the recording medium, and a driving voltage of the light source related to the exposure and an exposure amount applied to the recording medium. After storing a characteristic curve representing the relationship between the image data and the maximum density of the image based on the image data and determining the necessary exposure amount to be given to the recording medium to reproduce the maximum density A calculation unit that obtains the driving voltage of the light source necessary for obtaining the required exposure amount with reference to the characteristic curve, and a control unit that drives the light source with the driving voltage obtained by the calculation unit. It is characterized by.

  The characteristic curve is determined by a gamma characteristic of the recording medium. An exposure unit that includes the light source and that exposes the recording medium guides light emitted from the light source and extends in a predetermined main scanning direction along the recording medium. And a shutter that irradiates the recording medium with light guided by the light guide as light spots arranged in the main scanning direction by being opened and closed in accordance with the image data. . The light source may be a plurality of light emitting elements that emit light of two or more different colors.

  According to the printer of the present invention, the maximum density of the image is detected based on the image data, and after obtaining the necessary exposure amount to be given to the recording medium in order to reproduce this maximum density, the necessary exposure amount is obtained. Since the driving voltage of the light source required for this is obtained and the light source is driven with this driving voltage, it is possible to reduce power consumption without supplying an excessively high driving voltage to the light source.

  In addition, since the characteristic curve used for obtaining the required driving voltage of the light source is determined by the gamma characteristic of the recording medium, an accurate characteristic curve in accordance with the recording medium to be used can be obtained.

  An exposure unit that exposes the recording medium guides light emitted from the light source. The light guide extends in a predetermined main scanning direction along the recording medium, and the image data is arranged in the main scanning direction in which the light guide extends. Accordingly, the exposure unit can be configured in a compact manner by including a shutter that irradiates the recording medium with light guided by the light guide as light spots arranged in the main scanning direction. Moreover, it is preferable that the light source is a plurality of light emitting elements that respectively emit two or more different color lights.

  In FIG. 1 illustrating a printer according to an embodiment of the present invention, a printer 10 is a so-called mobile printer that is small, light, and thin, and includes two 3V primary batteries (for example, lithium batteries). An instant film pack is loaded in the casing 10a of the printer 10, and images are recorded while the ten instant sheet-like instant films in the instant film pack are sent out one by one. . The instant film of the present embodiment is a positive type that requires the maximum amount of light when recording an image with the maximum density.

  On the upper surface of the casing 10a of the printer 10, as operation buttons, a power switch (hereinafter referred to as power SW) 11 for instructing to turn on and off the power of the printer 10 and a print switch (hereinafter referred to as print SW). 12 is provided. A counter 13 indicating the remaining number of instant films is provided on the top surface of the housing 10a.

  The counter 13 is a mechanical counter, and when an unused instant film pack is loaded, a numerical value “10” indicating that the remaining number is 10 is displayed. Hereinafter, each time an image is recorded on the instant film, a numerical value indicating the remaining number is displayed, and when the image is recorded on the tenth instant film, the remaining number is zero. A numerical value “0” is displayed. When the instant film pack is removed, a blank state is displayed in which nothing is displayed.

  In addition, a transmission / reception unit 14 that performs transmission / reception by infrared communication is provided at an end of the printer 10. The transmission / reception unit 14 receives image data transmitted by infrared communication and transmits a signal for notifying the other party that the image data has been received.

  Further, the casing 10a is turned on when the power is turned on and is turned on and blinking at the time of infrared communication, the power LED 15 that is turned on when an error occurs in the infrared communication, and the built-in battery voltage is lowered. A low-battery display LED 17 that is lit to prompt the user to replace the battery is provided.

  A side door of the printer 10 is provided with a film door opening knob 18 for opening a film door, which will be described later, provided on the lower surface side of the printer 10, and a strap attachment portion 19 is provided at the corner portion. ing.

  In FIG. 2, the camera-equipped mobile phone 22 is operated with the infrared communication unit of the camera-equipped mobile phone 22 facing the transmission / reception unit 14 of the printer 10, and the image data of the image taken by the camera-equipped mobile phone 22 is transmitted via infrared Is transmitted to the printer 10 using.

  The printer 10 receives image data transmitted by infrared communication, and records a latent image based on the received image data on the instant film 24 by exposure, and visualizes the instant film 24 while printing the latent image 24. 10 is gradually discharged to the outside from the 10 outlets 26. Subsequently, when the print SW 12 is operated again, the same image as that image is re-recorded on another instant film.

  As shown in FIG. 3, a film door 28 that is opened by the operation of the film door opening knob 18 is provided on the lower surface side of the printer 10. The film door 28 is opened, and the instant film pack is placed in the medium loading chamber. Is loaded. In addition, the film door 28 is provided with a pack presence / absence confirmation window 28a for confirming whether or not an instant film pack is loaded. Further, a battery chamber 29 is provided adjacent to the film door 28 and is opened to mount a battery serving as a power source for the printer 10.

  In FIG. 4 showing a state in which the film door 28 is opened, the above-described pack presence / absence confirmation window 28a and spring members 31, 32 are provided inside the film door 28, and these spring members 31, 32 are provided. As a result, the instant film laminated in the instant film pack is pressed to the upper surface side of the printer 10.

  Opening the film door 28 exposes the media loading chamber 34 for loading instant film packs. On the left side of the drawing outside the medium loading chamber 34, an optical head 36 for writing an image on an instant film to be transported and a medium transport unit 38 are provided.

  Further, a claw 39 for sending out the instant film to the optical head 36 and the medium transport unit 38 side is provided in the medium loading chamber 34 on the right side of the drawing. With such a configuration, the instant film on the uppermost surface side of the printer 10 among the instant films in the instant film pack is pushed up by the nail 39 and is conveyed by the medium conveying unit 38, and an image is written by the optical head 36. It is.

  In FIG. 5 showing a part of the medium transport unit 38, the transport roller 42 is urged toward the transport roller 41 by a spring 44. The conveyance rollers 41 and 42 convey the both sides of the instant film 24 sent out from the instant film pack 45 while sandwiching both sides.

  The developing roller 46 is urged toward the developing roller 47 by a spring 48. The developing rollers 46 and 47 squeeze the developing pool 24a of the instant film 24 to develop the developer. Further, the medium conveyance unit 38 is guided between control plates 51 and 52 for controlling the developing agent positioned between the conveyance rollers 41 and 42 and the development rollers 46 and 47 and the instant film 24. A film guide frame 54 is provided. An optical head 36 is provided near the exit of the instant film pack 45.

  The medium transport unit 38 transports the instant film 24 from the predetermined transport start point Ps through the fixed writing point Pf to the predetermined transport end point Pe. The optical head 36 writes an image at the fixed writing point Pf on the instant film 24 being conveyed.

  In FIG. 6 showing the configuration of the optical head 36, the optical head 36 has a light guide 56 as a backlight that is long in the main scanning direction orthogonal to the sub-scanning direction, which is the transport direction of the instant film 24, and the incident port 56a. The LED 57R, 57G, 57B, which is a light emitting element as a backlight light source, a liquid crystal shutter array 58, and a SELFOC lens (registered trademark) 59.

  The LEDs 57R, 57G, and 57B emit red light (R light), green light (G light), and blue light (B light), which are the three primary colors of light, respectively, and record one line when recording one line of an image. Light is emitted sequentially. The maximum light emission amounts of the LEDs 57R, 57G, and 57B are determined based on image data as will be described in detail later.

  Each time the R light, G light, and B light are sequentially emitted, each light enters the light guide 56 through the entrance 56a and is emitted from the exit surface 56b of the light guide 56 facing the instant film 24 side. The amount of light is adjusted by each shutter of the liquid crystal shutter array 58, and an image is formed at the same point on the exposure surface of the instant film 24 through the Selfoc lens (registered trademark) 59 located ahead.

  In this embodiment, 480 light spots having gradations corresponding to the image data are controlled on the instant film 24 by controlling the opening time of each shutter according to the image data using the liquid crystal shutter array 58 having 480 elements. Recorded as a latent image. This is recorded for 640 lines also in the sub-scanning direction, and 480 × 640 light spots are recorded as a latent image on the instant film. Each light spot is a latent image representing a color image in which light of three colors of R, G, and B is recorded at the same point by the SELFOC lens (registered trademark) 59.

  In FIG. 7 showing the control system inside the printer, the printer 10 includes, in addition to the optical head 36, the main board portion 60, sub-board portion 62, FPI portion 64, ENCPI portion 66, COUNTPI portion 68, cam switch 70, The IrDA transmission / reception unit 72 and the DC motor 74 provided in the transmission / reception unit 14 are provided.

  The sub board 62 includes the power SW 11, the print SW 12, and the display LED 63 described above. The display LED section 63 includes the power LED 15, the communication error LED 16, the low battery display LED 17, the counter backlight LED (not shown) provided on the back side of the counter 13, and the like. .

  The main board 60 is provided with flexible cables 78 and 79 for connecting the optical head 36 to the main board 60. The optical head 36 has three color lights R, G, and B from the LEDs 57R, 57G, and 57B based on the image data received by the transmission / reception unit 14 in synchronization with the write instruction pulse on the instant film 24 in the middle of conveyance. , The latent image is written on the instant film 24. Further, the printer 10 includes two 3V primary batteries 86.

  A power supply voltage VB of 6V from the primary battery 86 connected in series is applied to the main board 60. The main board 60 includes an MPU (Micro Processor Unit) 91, an oscillator 92, a reset circuit 93, a flash memory (FLASH) 94, and an SDRAM 96.

  The MPU 91 comprehensively controls the operation of the printer 10. The oscillator 92 generates an oscillation signal having a predetermined frequency and supplies it to the MPU 91 as an operation clock signal. The reset circuit 93 outputs a reset signal for initializing the MPU 91.

  The flash memory 94 is a non-volatile memory. In the flash memory 94, an exposure amount (Treq) necessary to reproduce the R, G, and B images from the maximum density at the time of shipment from the factory. A characteristic curve created by acquiring in advance for each of R, G, and B based on the gamma (γ) characteristic of the instant film 24 based on the gamma (γ) characteristic of the instant film 24 and the look-up table for conversion to P (see FIG. 8) is stored.

  In FIG. 8 showing the characteristic curve P, Vmax is the maximum drive voltage that can be theoretically applied to the LED, and Vmin is the minimum drive voltage. The exposure amount given to the instant film by the maximum drive voltage Vmax becomes the maximum exposure amount Tmax, and the exposure amount given to the instant film by the minimum drive voltage Vmin becomes the minimum exposure amount Tmin.

  However, from the gamma (γ) characteristics of the instant film 24 of the present embodiment, the density range in which the instant film 24 actually develops color is narrower than the range corresponding to the exposure amount range of Tmax to Tmin, and exposure of Tmax to Tmin. The exposure amount range of Ta to Tb is narrower than the amount range.

  Therefore, conventionally, the LED is always driven with the driving voltage Va for generating the exposure amount Ta so as to correspond to the actual maximum density of the instant film 24, and the exposure range given to the instant film 24 becomes Ta to Tb. In addition, the opening / closing time of each shutter of the liquid crystal shutter array 58 is adjusted.

  However, the maximum density of an image to be printed may be lower than the maximum density that develops color depending on the exposure amount Ta. Therefore, according to the present invention, when printing such an image, the LED is turned on with a necessary drive voltage Vreq (<Va) corresponding to a necessary exposure amount Treq (<Ta) necessary to develop the maximum density of the image. The opening and closing time of each shutter of the liquid crystal shutter array 58 is adjusted so that the exposure range given to the instant film 24 is Treq to Tb. Thereby, the power consumption for (Va−Vreq) can be reduced. The characteristic curve P shown in FIG. 8 is the case where the instant film 24 is a positive type. In the case of the negative type, the gradation of the image is inverted. It becomes the shape that I let you.

  The SDRAM 96 is a volatile memory, and the SDRAM 96 stores image data sent from the camera-equipped mobile phone 22.

  The main board 60 is supplied with a power supply voltage VB of 6 V, a power supply section 98 that outputs a voltage of 2.5 V, a power supply section 99 that outputs a voltage of 3.3 V, and a voltage of 15 V. A DC / DC converter 100 is provided. Further, a power supply control unit 102 that controls the power supply units 98 and 99 and the DC / DC converter 100 in response to an instruction from the MPU 91 is also provided. Here, a voltage of 2.5 V is supplied to the MPU 91 and a voltage of 3.3 V is supplied to peripheral circuits other than the MPU 91.

  Further, the main board unit 60 includes a BC unit 104, a TPG unit 106, an oscillator 110, an IrDA / LCS control unit 112, and a head LED driving unit 114.

  The BC unit 104 checks whether or not the power supply voltage VB of the primary battery 86 has decreased below a predetermined value. When the MPU 91 determines that the power supply voltage VB of the primary battery 86 is lower than a predetermined value with reference to this check result, the low-battery display LED 17 is turned on to prompt the user to replace the battery. . The TPG unit 106 turns on and off the 15 V voltage output from the DC / DC converter 100.

  The MPU 91 detects the maximum density of the image based on the image data stored in the SDRAM 96, and refers to the lookup table stored in the flash memory 94 for the exposure amount (Treq) required to reproduce the maximum density. Further, the required drive voltage (Vreq) of the LED corresponding to the required exposure amount (Treq) is obtained from the characteristic curve P stored in the flash memory 94. This Vreq is obtained for each of the LEDs 57R, 57G, and 57B.

  The oscillator 110 generates an oscillation signal having a predetermined frequency and supplies it to the IrDA / LCS control unit 112. The IrDA / LCS control unit 112 controls the IrDA transmission / reception unit 72 and the optical head 36 based on the oscillation signal from the oscillator 110.

  The IrDA transmission / reception unit 72 includes a light projecting element and a light receiving element for performing infrared communication, and the IrDA / LCS control unit 112 sends data photoelectrically converted by the light receiving element to the MPU 91, or from the MPU 91. Data for notifying an external device to that effect is transmitted to the outside via the light projecting element.

  Further, the IrDA / LCS control unit 112 sends a control signal corresponding to the image data to the optical head 36 via the flexible cable 78 in accordance with an instruction from the MPU 91. This control signal controls the opening time of each shutter of the liquid crystal shutter array 58 in the optical head 36. Further, the head LED drive unit 114 drives the LEDs 57R, 57G, and 57B with each drive voltage Vreq via the flexible cable 79 based on an instruction from the MPU 91.

  Further, the main board 60 is provided with a PI driver 116. The PI drive unit 116 drives the FPI unit 64, the ENCPI unit 66, and the COUNTPI unit 68. Here, the FPI unit 64, the ENCPI unit 66, and the COUNTPI unit 68 will be described.

  The FPI unit 64 is a photo interrupter for detecting the presence or absence of the instant film 24 and outputting a film signal FILM_PI described later. In the initial state in which the instant film 24 is accommodated in the instant film pack, the FPI unit 64 outputs the “H” level as the film signal FILM_PI. When the motor 74 rotates and the instant film 24 is conveyed and the leading edge thereof is detected, the film signal FILM_PI changes from the “H” level to the “L” level. Further, when the trailing end is detected while the instant film 24 continues to be conveyed, the film signal FILM_PI changes from the “L” level to the “H” level.

  The ENCPI unit 66 is a photo interrupter for outputting an encode signal ENC, which is composed of a pulse train synchronized with the rotation of the motor 74. The COUNTPI unit 68 is a photointerrupter for the counter 13 to detect a reset state (a state in which the instant film pack is removed).

  A cam switch 70 is connected to the main board 60. This cam switch 70 is a switch for monitoring the initial position in the transport mechanism of the printer 10. At the initial position, the cam switch 70 outputs a “H” level as the cam switch signal CAMSW, and the transport is performed as the motor 74 rotates. When the mechanism deviates from the initial position, the cam switch signal CAMSW changes from the “H” level to the “L” level. Further, the main board part 60 is provided with a motor driving part 118.

  The operation of the printer 10 thus configured will be described with reference to the flowchart shown in FIG. Image data is transmitted in advance from the camera-equipped mobile phone 22 to the printer 10 by infrared communication. The image data captured by the IrDA transmission / reception unit 72 via the transmission / reception unit 14 is stored in the SDRAM 96.

  When the print SW 12 is pressed (st1), the MPU 91 reads the image data from the SDRAM 96, and based on this, detects the maximum density of the R component (R image) of the image (st2). Subsequently, the MPU 91 obtains an exposure amount Treq necessary for reproducing the maximum density of the R image with reference to a lookup table stored in the flash memory 94 (st3). Further, the required drive voltage Vreq of the LED 57R corresponding to the required exposure amount Treq is obtained with reference to the characteristic curve P for R image (st4). Similarly, the necessary drive voltages Vreq for the LEDs 57G and 57B are obtained.

  Next, the claw 39 scoops out the uppermost instant film 24, and the conveyance rollers 41 and 42 sandwich the both sides of the instant film 24 fed from the instant film pack 45 to start conveyance (st5).

  When the end of the exposure surface of the instant film 24 faces the optical head 36, the transport of the instant film 24 is switched to the step transport for each line. In addition, the MPU 91 reads one line of the image data of the R image from the SDRAM 96 (st6), sends a command to the head LED control unit 114, and causes the LED 57R of the optical head 36 to be used for the R image via the flexible cable 79. Drive with the required drive voltage Vreq (st7).

  The MPU 91 sends a command to the IrDA / LCS control unit 112 and sends a control signal corresponding to the image data for one line of the R image to the optical head 36 via the flexible cable 78. The opening time of each shutter of the liquid crystal shutter array 58 is adjusted by this control signal, and an R image for one line is recorded as a latent image on the instant film 24 (st8).

  Subsequently, the LED 57G is driven with the required drive voltage Vreq for the G image, and the opening time of each shutter of the liquid crystal shutter array 58 is adjusted according to the image data for one line of the G image, and the R image is recorded. A G image is recorded as a latent image on the same line on the instant film 24. Subsequently, the B image is recorded as a latent image on the same line.

  After the R, G, and B images are recorded on the same line (st9), the instant film 24 is stepped by the width of one line (st10), and each of the R, G, and B is transferred to the next line. An image is recorded as a latent image. When images are recorded as latent images on all lines in this way (st11), the instant film 24 is changed to a high-speed delivery conveyance speed and conveyed.

  The development reservoir 24a is crushed by the developing rollers 46 and 47, and the instant film 24 is discharged to the outside from the delivery port 26 of the printer 10 while developing the developer in the instant film 24 (st12). When a predetermined development time elapses, a color image appears on the instant film 24.

  In the embodiment described above, the instant film to be used is a positive type, but a negative type may be used. In this case, as described above, a characteristic curve obtained by inverting the characteristic curve P to the left and right may be used. Further, a means for discriminating the positive / negative type of the instant film to be used may be provided, and the characteristic curve to be used may be selected.

  Moreover, in the said embodiment, although R, G, B (3 colors) LED was used as a light source, this invention is not limited to this, For example, white LED which light-emits white light, R, G, B A filter may be used. Further, the color is not limited to three colors, and may be one color (monotone), two colors, or four colors by adding one color to R, G, and B.

  In the above embodiment, image data is captured by infrared communication. However, the present invention is not limited to this, and a USB port may be provided, for example, and image data may be captured by a USB memory.

  In the above embodiment, the image is written on the instant film being transported. However, the present invention is not limited to this, and the image is written on the instant film by moving the optical head in the medium loading chamber. May be. Alternatively, a planar liquid crystal panel that displays an image for one frame or a plurality of lines may be used to form an image displayed on the recording medium with an optical lens and be exposed.

  Further, although the above embodiment is a printer using an instant film, it can be applied to any printer that records a latent image on a photosensitive recording medium.

1 is a perspective view illustrating a printer according to an embodiment of the present invention obliquely from the front. It is explanatory drawing of the printer which shows a mode that an image is recorded on an instant film based on the image data sent from the mobile telephone with a camera, and is discharged | emitted. It is the perspective view which looked at the lower surface side of the printer from diagonally upward. FIG. 3 is a perspective view showing a state of the printer with the film door opened. FIG. 3 is a cross-sectional view illustrating a part of a medium transport unit. It is a schematic diagram which shows the structure of an optical head. FIG. 2 is a configuration block diagram showing a control system inside the printer. It is a graph which shows the characteristic curve which calculates | requires the required drive voltage of LED from the required exposure amount of an instant film. It is a flowchart which shows a main sequence.

Explanation of symbols

10 Printer 24 Instant film 36 Optical head 56 Optical guide 57R, 57G, 57B LED
58 LCD shutter array 91 MPU
94 Flash Memory 112 IrDA / LCS Controller P Characteristic Curve Treq Required Exposure Vreq Required Drive Voltage

Claims (4)

In a printer that records an image on a recording medium as a latent image by performing exposure according to the image data on the recording medium,
A storage unit preliminarily storing a characteristic curve representing a relationship between a driving voltage of a light source related to the exposure and an exposure applied to a recording medium;
Based on the image data, the maximum density of the image is detected, the required exposure amount to be given to the recording medium to reproduce the maximum density is obtained, and then the required exposure amount is obtained with reference to the characteristic curve. A calculation unit for obtaining a driving voltage of a light source necessary for
And a control unit that drives the light source with the drive voltage obtained by the calculation unit.   The printer according to claim 1, wherein the characteristic curve is determined by a gamma characteristic of the recording medium. An exposure unit that includes the light source and applies exposure to the recording medium,
A light guide for guiding light emitted from the light source and extending in a predetermined main scanning direction along the recording medium;
A shutter that is arranged in the main scanning direction in which the light guide extends, and irradiates the recording medium with light guided by the light guide as light spots arranged in the main scanning direction by opening and closing according to the image data. The printer according to claim 1 or 2, wherein   4. The printer according to claim 1, wherein the light source is a plurality of light emitting elements that respectively emit two or more different color lights.

Images