Abstract:
A frame memory for extending data of an picture demonstrated on an picture display device is effectively utilized to effect the printing of an picture demonstrated on the picture display device inexpensively and appropriately. To this end, there is provided a printing data creating unit  26  for acquiring data of the picture demonstrated on a display monitor  30  from a frame memory  22  which holds the data from frame to frame. The printing data creating unit  26  prepares data for printing based on the so-acquired data.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to a digital broadcast reception apparatus for receiving digital broadcast for preparing data for printing, and a picture printing method for printing a picture for demonstration on a picture display device. 
   2. Description of Related Art 
   In printing a picture demonstrated on a display monitor of a television receiver, there is known a method employing an analog video printer. 
   In this method, the analog video printer is supplied, from the television receiver, with the analog picture signals corresponding to a picture demonstrated on a display monitor of the television receiver. The analog picture signals, supplied to the analog video printer, are digitized and sequentially written in a frame memory within the analog video printer, in terms of a frame of the picture demonstrated on the display monitor as a unit. 
   If a user issues a command for printing a picture demonstrated on the display monitor, the frame memory of the analog video printer ceases to be updated to determine a picture to be printed. From the frame memory, data of the picture to be printed is read out and converted into data for printing. The analog video printer executes printing based on these printing data. This causes printing of the picture demonstrated on the display monitor of the television receiver. 
   Recently, digital television broadcast, in which television broadcast is executed by digital signals, was launched, and the television broadcast in its entirety is predicted to be executed in future by digital signals. 
   In a digital television receiver, receiving digital television broadcast, received digital picture signals are sequentially written in a frame memory of the digital television receiver in terms of a frame of the picture demonstrated on the display monitor as a unit. Based on the digital picture signals, extended on the frame memory, data for monitor display is prepared, in keeping with the demonstrating mode on the display monitor, such as interlacing mode or progressive mode, so that a picture id demonstrated on the display monitor. 
   If, in a digital television receiver receiving the digital television broadcast, described above, a picture demonstrated on the display monitor is to be printed, it may be contemplated to provide a page memory for printing in the digital television receiver, in addition to the frame memory used for extending data of a picture demonstrated on the display monitor, to write received digital picture signals sequentially in this page memory for printing. If a printing command is issued by the user, the data is taken out from the page memory for printing and converted into printing data suited for the printer, so as to be then transmitted to the printer through an interface, such as a centronics cable, in order to effect the printing. 
   However, with this method, the page memory for printing is required in addition to the frame memory in which to extend data of a picture to be demonstrated on the display monitor, thus increasing the cost. 
   SUMMARY OF THE INVENTION 
   It is therefore an object of the present invention to provide a digital broadcast receiving apparatus having a frame memory for storing data of a picture demonstrated on a picture display device, such as a digital television receiver, in which, by effectively utilizing this frame memory, a picture demonstrated on the picture display device can be printed inexpensively and appropriately. 
   It is another object of the present invention to provide a picture printing method in which a picture demonstrated on a picture display device can be printed inexpensively and appropriately. 
   In one aspect, the present invention provides a digital broadcast reception device including reception means for receiving digital broadcasting, storage means for storing picture data of digital broadcasting, received by the reception means, in terms of a frame of an picture demonstrated on an picture display device s a unit, and printing data creating means for acquiring the picture data stored in the storage means for preparing data for printing based on the picture data. 
   In this digital broadcast reception device, digital broadcast is received by the reception means, and picture data of the digital broadcast, as received by this reception means, is stored in the storage means from one frame of the picture demonstrated on the picture display device to another. 
   If a command for printing an picture demonstrated on the picture display device is issued by a user, the printing data creating means acquires picture data stored in the storage means to prepare data for printing based on the picture data. 
   The data for printing, prepared by the printing data creating means, is routed to the printing means, which is connected to the printing data creating means over an internal bus. The printing means prints a picture demonstrated on the picture display device based on the printing data prepared by the printing data creating means. 
   In the digital broadcast reception device of the present invention, in which the printing data creating means acquires picture data of digital broadcast from storage means, adapted for storing a picture demonstrated on the picture display device, from one frame of the picture to another, and data for printing is prepared based on the image data, there is no necessity of additionally providing a page memory for preparing the data for printing. 
   So, with the present digital broadcast reception device, the image demonstrated on a picture display device can be printed inexpensively and appropriately. 
   Moreover, if, in this digital broadcast reception device, the printing means for printing a picture demonstrated on the picture display device is connected to the printing data creating means over an internal bus, the data for printing can be transmitted speedily to the printing means. 
   In another aspect, the present invention provides an picture printing method including storing received digital broadcast picture data in terms of a frame of an picture demonstrated on an picture display device s a unit, acquiring the picture data stored in the storage means to prepare data for printing based on this picture data and printing an picture for demonstration on the picture display device based on the data for printing. 
   In this picture printing method, in which digital broadcast image data is acquired from storage means, configured for storing the image data from one frame of the picture demonstrated on the picture display device to another, and data for printing is acquired on the basis of the so-acquired picture data, it is unnecessary to additionally provide a page memory for preparing the data for printing. 
   Therefore, in the present picture printing method, the picture demonstrated on the picture display device can be printed inexpensively and appropriately. 
   Moreover, in the digital broadcast reception device of the present invention, in which, if a command for printing a picture demonstrated on the image display device is issued by the user, the printing data creating means acquires picture data from storage means adapted for storing image data in terms of a frame of the picture demonstrated on the picture display device, as a unit, and prepares the data for printing on the basis of the so-acquired picture data, it is unnecessary to provide another page memory for preparing the data for printing. Therefore, in the present digital broadcast reception device, the picture demonstrated on the picture display device can be printed inexpensively and appropriately. 
   In addition, in the picture printing method of the present invention, in which, if a command for printing a picture demonstrated on the image display device is issued by the user, picture data are acquired from storage means adapted for storing image data in terms of a frame of the picture demonstrated on the picture display device, as a unit, and the data for printing are prepared on the basis of the so-acquired picture data, it is unnecessary to provide another page memory for preparing the data for printing. Therefore, in the present picture printing method, the picture demonstrated on the picture display device can be printed inexpensively and appropriately. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a schematic perspective view showing the overall appearance of a digital television printer according to the present invention. 
       FIG. 2  is a block diagram showing an internal structure of the digital television printer. 
       FIG. 3  shows the relation between a picture demonstrated on a display monitor and a picture printed on a printing sheet of a printer. 
       FIG. 4  is a block diagram showing a driving circuit of a printer provided on the digital television printer. 
       FIG. 5  is a schematic view showing a printing processing unit of the printer. 
       FIG. 6  is a flowchart for illustrating the operation of the digital television printer. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to the drawings, preferred embodiments of according to the present invention will be explained in detail. 
     FIG. 1  shows an overall appearance of a digital television printer embodying the present invention. The digital television printer  1 , shown in  FIG. 1 , includes a digital broadcast reception device according to the present invention, a display monitor  30 , as a picture display device, and a printer  40  as printing means, these components together making up a sole apparatus. 
     FIG. 2  shows a block diagram showing the internal structure of the digital television printer  1 . 
   The transmitting station combines moving picture data or still picture data, created by a broadcasting station, a service provider or a contents provider, into a hybrid signal, which is sent out as a ground wave or a cable signal. If necessary, the transmitting station scrambles the hybrid signal to prohibit a party other than a subscribed from reading out the information. 
   The hybrid signal, transmitted from the transmitting station, is received through an antenna, a cable modem and so on, by a tuner  11  of the digital broadcast reception device. At this time, a CPU  12  of the digital broadcast reception device exploits a RAM  13  as a work area to execute the program stored in the ROM  14  to manage control such as channel selection. 
   The hybrid signal, received by the tuner  11 , is separated by a front-end unit  15  into a baseband wave, and descrambled by a descrambling unit  16 . The descrambled hybrid signal is separated by a demultiplexer  17  into variable data, such as the moving picture data or still picture data, created by the broadcasting station, service provider or the contents provider. 
   The variable data, separated by the demultiplexer  17 , are inputted to separate decoders, associated with the respective data, for decoding. Specifically, the MPEG2 data, as the moving picture data for a broadcasting station, are routed to an MPEG2 decoder  18  for decoding, whilst the MPEG data, received as still picture data for broadcasting, are routed to an MPEG decoder  19  for decoding, and HTML data, mainly used in a WWW home page, is inputted to an HTML decoder  20 , similarly for decoding. 
   The MPEG2 data, decoded by the MPEG2 decoder  18 , is written in a frame memory  22 , under control by a frame memory controller  21 . The MPEG data, decoded by the MPEG decoder  19 , and the HTML data, decoded by the HTML decoder  20 , are written in the frame memory  22 , under control by the frame memory controller  21 , following the preparation of a raster size of the letter information and that of the picture information by a graphic generator  23 . 
   In the frame memory  22 , the above variable data are written from one frame of a picture demonstrated on a display monitor  30  to another. That is, the frame memory  22  transiently holds data making up a frame of a picture demonstrated on the display monitor  30  (picture data). 
   The picture data written in the frame memory  22  is read out by a display raster generator  24 . The display raster generator  24  formulates display data, in keeping with the display mode (interlacing or progressive mode) on the display monitor  30  to route the display data to the display monitor  30 . This demonstrates a picture on the display monitor  30 . 
   If a command by a user for printing a picture demonstrated on the display monitor  30 , that is picture data present in the frame memory  22 , is inputted from a printing command input mechanism, such as a keypad  25  of the digital broadcast reception device, the CPU  12  utilizes the RAM  13  as a work area to execute the program stored in the ROM  14  to start the printing operation. 
   Specifically, the CPU  12  is perpetually monitoring the state of the printing command inputting equipment, such as a keypad  25  and, if the CPU verifies that a printing command has been issued by the user, the CPU  12  first controls the writing operation of the frame memory controller  21  so that no new data will be written in the frame memory  22  until printing comes to a close. The purpose of doing this is to prevent picture data from being rewritten during printing to effect proper printing in case the time needed until completion of printing of picture data in the frame memory  22  is longer than the time needed in updating picture data for one frame in the frame memory  22  to demonstrate a new picture plane in the display monitor  30 . 
   The CPU  12  then requests a printing data creating unit  26  to acquire picture data from the frame memory  22  to create data for printing based on this picture data. 
   For monochromatic printing, the printing data creating unit  26  extracts a luminance signal Y from picture data constituted by YUV signals, made up of the luminance signal Y and color difference signals U and V, to use the extracted signal as monochromatic picture signals. In order to facilitate picture processing by the printer  40 , it is possible for the printing data creating unit  26  to convert the YUV signal into RGB signal to use the luminance signal Y as found from the RGB signal by the following equation:
 
 Y= 0.2126 R+ 0.7152 G+ 0.0722 B  
 
as monochromatic picture signals.
 
   The printing data creating unit  26  then converts the resolution of picture data, prepared for demonstration on the display monitor, to provide the resolution matched to the picture for printing by the printer  40 . For example, if the printer  40  is capable of printing at 300 dpi and the picture data is data demonstrating a picture at 730 p: 1280 (H)×720 (V), according to one of the standards for digital TV broadcasting, a picture demonstrated on the display monitor  30  can be printed to an A4 size by the printer  40 , by the printing data creating unit  26  effecting conversion of the picture data resolution to effect density conversion (enlargement) of the number of pixels of a raster by a factor 0 f 2.675. 
   Finally, the printing data creating unit  26  executes half-toning in keeping with the number of gradations that can be represented by the printer  40  to complete data for printing. The half-toning is the processing of data conversion of Y-signals, quantized in 256 gradations, by a organized dithering method or an error diffusion method, to enable pseudo-gradation to be represented in case a printer capable of representing only two gradations, such as a laser beam printer, is used as the printer  40 . 
   For color printing, the printing data creating unit  26  first converts the YUV signals into RGB signals to provide for facilitated picture processing on the printer  40 . After the picture data resolution conversion, as discussed above, the printing data creating unit  26  converts the YUV signals into CMY signals for coping with the cyan, magenta and yellow inks on the printer  40 . Finally, the data for printing is prepared by the half-toning processing as discussed above. 
   The data for printing, thus prepared, is sequentially transmitted to the printer  40 . This causes a picture demonstrated on the display monitor  30  to be printed by the printer  40 . 
   In this digital television printer  1 , the printer  40  is connected by a high-speed internal bus  27  to the printing data creating unit  26  of the digital broadcast reception device. The data for printing, prepared by this printing data creating unit  26 , is transmitted to the printer  40  over this high-speed internal bus  27 . So, the digital television printer  1  is able to transmit the data for printing at an elevated speed to the printer  40  to effect the printing speedily. 
   The printer  40  as printing means is now explained with reference to  FIGS. 4 and 5 . Here, a monochromatic laser printer, capable of achieving high-speed printing, is used as the printer  40 , in order that the time during which the picture demonstrated on the display monitor  30  is paused during printing will be as short as possible. The present invention is, however, not limited to this embodiment since a printer operating under different printing methods, such as an ink jet printer, a thermally sensitive printer or a sublimation printer may also be used as the printer  40 . 
   The printer  40  includes a driving circuit as shown in  FIG. 4  and a printing processing unit as shown in  FIG. 5 . 
   The data for printing, transmitted to the printer  40  over the high-speed internal bus  27 , is converted by a sync memory  41 , a laser control circuit  42  and a laser driver  43  into a laser output signal which is sent to a laser output circuit  44 . This causes the laser light corresponding to the laser output signal to be radiated by the laser output circuit  44 . 
   The laser light outputted by the laser output circuit  44  is reflected by a reflecting surface of a polygonal mirror  47 , rotationally driven by a polygonal mirror driving motor  46 , controlled by a polygonal motor driver  45 , to scan the peripheral surface of a photosensitive drum  50  linearly through a lens  48  and a reflective mirror  49 . 
   The photosensitive drum  50  is rotationally driven in the direction indicated by arrow A in  FIG. 5 , with the laser light scanning direction as the rotational axis, by a drum driving motor  52 , controlled by a motor driver  51 . 
   The photosensitive drum  50  is electrically charged by an electronic charger  54 , controlled by a charger driver  53 , as the photosensitive drum  50  is run in rotation. By the peripheral surface of the electrically charged photosensitive drum  50  being scanned by the laser light, a latent picture corresponding to data for printing is formed on the peripheral surface of the photosensitive drum  50 . 
   A toner is supplied from a developer  57  to a latent picture formed on the peripheral surface of the photosensitive drum  50  to form a toner picture. This toner image is moved with rotation of the photosensitive drum  50  and, when the toner picture is brought to a position facing a transcription charger  58 , controlled by a charger driver  53 , the toner picture is transcribed to printing sheet  61 , transported from a sheet feed cassette, not shown, through transport rolls  59 ,  60 . The printing sheet  61 , onto which the toner picture has now been transcribed, is transported on a paper path, not shown, and is subjected to fixing by a fixing unit, not shown. The resulting printed sheet is conveyed out of the printer  40 . This prints an picture demonstrated on the display monitor  30 . 
   The operation of the digital television printer  1 , embodying the present invention is now explained with reference to  FIG. 6 . 
   First, at step  1  of the picture display sequence, digital broadcast is received by a digital broadcast reception device. Then, at step  2 , picture data of the received digital broadcast is written in the frame memory  22  of the digital broadcast reception device, from one frame of the picture demonstrated on the display monitor  30  to another. At step  3 , the picture data in the frame memory  22  is transmitted to the display monitor  30  where the picture is demonstrated. 
   At step  4 , it is checked by the CPU  12  whether or not a command by a user for printing a picture demonstrated on the display monitor  30  has been issued. If the CPU verifies that the command for printing the picture demonstrated on the display monitor  30  has not been issued, the CPU  12  reverts to step  2  to update the frame memory  22  to proceed to write the next picture data. If the CPU verifies that the command for printing the picture demonstrated on the display monitor  30  has been issued, the CPU  12  proceeds to stop the updating of the frame memory  22  to start the picture plane printing sequence. 
   In the picture plane printing sequence, the printing data creating unit  26  first acquires picture data at step  6  from the frame memory  22 . Then, at step  7 , the printing data creating unit  26  prepares data for printing, based on the picture data acquired from the frame memory  22 . 
   Then, at step  8 , the data for printing is transferred to the printer  40  where the picture demonstrated on the display monitor  30  is printed by the printer  40 . Then, at step  9 , the CPU  12  verifies whether or not the printing has come to a close. If it is verified that the printing has not come to a close, the printing sequence is continued. If it is verified that the printing has come to a close, the CPU reverts to step  2  to update the frame memory  22  to proceed to write the next picture data. 
   In the digital television printer  1  according to the present invention, as described above, in which, when a command for printing an picture demonstrated on the display monitor  30  is issued, the printing data creating unit  26  acquires picture data of an picture demonstrated on the display monitor  30  from the frame memory  22  to prepare data for printing based on these picture data to transmit the data for printing to the printer  40 , which then prints the picture demonstrated on the display monitor  30 , the picture demonstrated on the display monitor  30  can be printed appropriately and speedily despite its simplified structure. 
   In the foregoing description, the digital television printer  1  is made up of a digital broadcast reception device, a display monitor  30  and a printer  40 , integrated together to a unitary structure. The present invention is, however, not limited to this structure and may be configured so that one or both of the display monitor  30  and the printer  40  is separated and connected over an external connection cable to the digital broadcast reception device.