Font managing apparatus for a character generator

Abstract

In a printing system having insertable font cartridges, a font managing apparatus selects fonts when there is a change in the font to be printed. For example, when a font cartridge is detached or interchanged, the font managing apparatus detects the interchange or detachment of the font cartridge and reselects another font. The font managing apparatus can also change the attributes of the font to be printed.

Claims

What is claimed is:

1. A font managing apparatus for a character generator which generates character images based on font data stored in a font memory, said font data including pattern data and a group of attributes of at least one kind of font, comprising:

an entry means for entering information necessary for designating a font to be used for generating characters;

first memory means for memorizing plural groups of attributes;

second memory means for memorizing addresses of respective groups of attributes in said first memory means;

group managing means for checking whether a group of attributes corresponding to a designated font is memorized in said first memory means or not, said group managing means loading the corresponding group of attributes into said first memory means if it is not memorized therein and writing an address of said corresponding group of attributes in said first memory means; and

means for deleting data of a group of attributes which is loaded in said first memory means earliest.

2. A font managing apparatus as claimed in claim 1, in which said first memory means is comprised of a ring buffer.

3. A font managing apparatus for a character generator for managing plural available fonts, comprising:

an entry means for entering font information including information regarding a value of a relative level for reflecting the strength of a predetermined characteristic of a font to be designated;

first memory means for storing data which signifies attributes of said available fonts;

calculation means for calculating an absolute level for reflecting the strength of said characteristic based on a value of the level of a font which has been selected and said value of the relative level;

second memory means for memorizing a table which relates the attributes with the absolute level; and

a font selection means for selecting a font among said available fonts which has attributes corresponding to the absolute level referring to said table of the second memory means and the data stored in said first memory means.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a font managing apparatus for a character generator in which plural font pattern data are stored.

2. Description of Prior Art

Conventionally, the character generator of bit map type has been well known. In the character generator of bit map type, each character is formed as a bit image on a bit map memory according to font pattern data stored in a font memory. In a character generator of bit map type, fonts of several kinds are selectably stored in the font memory. In order to increase the number of selectable fonts, interchangeable font cartridges each of which has a ROM or character generator together with a command for designating a font. The character generator transforms each of transmitted code data into a bit image consulting with pattern data of the designated font. Bit images thus formed are sent to a printer and, thereby, the document is printed out in accordance with the designated font.

In a character generator which provides a variety of interchangeable font cartridges, an area for registering management information of individual fonts is provided for managing available fonts in a system RAM. Upon starting the character generator or when one or more font cartridges are interchanged, respective management information of available fonts is registered or renewed into the font managing area of the system RAM.

As a memory for memorizing font data which is provided in a font cartridge, a rewritable RAM is used other than a ROM. As a rewritable RAM, a RAM backed up with a back up power source is desirably used to hold font data even when the character generator is turned off. The RAM of this type has an external by operable input switch and font data is considered to be loaded down thereinto from the host computer as far as the external input switch is switched on.

If the switch is switched off or in the case of a font RAM which does not provide a back up power source, font data can be loaded down thereinto from the host computer.

In a character generator wherein plural font cartridges are settable and interchangeable, there is a possibility such that the font cartridge presently selected is drawn out or moved to another slot even when editing operation of character images is executed.

In such a case, it becomes necessary to reselect a font to be used.

Conventionally, when the font cartridge in use is drawn out, a font cartridge set in the slot adjacent to that of the drawn out font cartridge is selected automatically. However, if the font is reselected in this way, the font is changed one to another on the way of printing and this worsens quality of print.

In another conventional character generator, the operation thereof is automatically stopped as an error when the font cartridge in use is drawn out. In this case, it becomes necessary to load down font data again in order to start the suspended printing operation. Upon loading down font data, if a command for selecting a font contained in neither of font cartridges having been set is entered, it is processed as an error which urges to cancel it.

In the character generator of this type, a font is designated by appointing a slot number or a font name. Accordingly, it becomes necessary for an operator to have a preliminary knowledge of the slot number or font name regarding the desired font. However, it is difficult to designate the desired font exactly since each font is defined by attributes of font such as font name, pitch (print width), point (height of character), weight (print thickness) and the like which are unfamiliar to an ordinary user. This invites miss operation often.

In a font memory contained in a font cartridge, directory of font data which includes address information with respect to font patterns corresponding to character codes is also stored. Upon accessing the font memory, address information of a font pattern corresponding to a character code sent from the host computer is read out from the directory at first and, thereafter, the font pattern designated by the address information is read out. Accordingly, it is always needed to access the directory of the font memory every character. This access operation is done parallel to imaging operation of characters and, therefore, access time becomes long. This fairly limits the processing time.

In JP-A 116551/1986, there is disclosed a font managing system wherein address information of directories of individual font memories is stored as a directory address table in a system RAM in order to manage directories. Upon accessing a font pattern, the directory address table is accessed at first and, then, the corresponding font pattern stored in the font memory is read out.

If the memory area to be assigned to the directory address table is reasonably narrow so as to shorten the addressing time, character imaging operation can be executed at a high speed.

However, in JP-A 116551/1986, directories of all available fonts are registered in the directory address table of the system RAM. Due to this, the system RAM must have a large volume.

SUMMARY OF THE INVENTION

One object of the present invention is to provide a font managing apparatus for a character generator having selectable fonts which is able to maintain quality of print as fine as possible even when it becomes necessary to reselect a font in printing or imaging characters.

Another object of the present invention is to provide a font managing apparatus for a character generator providing interchangeable font cartridges wherein an arbitrary font cartridge can be interchanged even if it is used for character imaging and can be set if it is not set yet without causing errors.

One more object of the present invention is to provide a font managing apparatus for a character generator having selectable fonts which is able to manage directories of various fonts efficiently without increasing a volume of a system RAM.

Further object of the present invention is to provide a font managing apparatus for a character generator having a variety of selectable fonts wherein a desirable font can be designated in the basis of a human sense thereto without indicating attributes thereof exactly.

BRIEF DESCRIPTION OF DRAWINGS

These and other objects and features of the present invention will become more apparent when the preferred embodiment of the present invention is described in detail with reference of accompanied drawings in that;

FIG. 1 is a block diagram of a printer system to which the present invention is applied;

FIG. 2 is a block diagram showing a bit map data processor and a print engine of the printer system shown in FIG. 1;

FIG. 3 is a block diagram showing a bit map controller provided in the bit map data processor shown in FIG. 2;

FIG. 4 is a diagram showing the composition of a font cartridge;

FIGS. 5(a) and 5(b) show a structure of a code in a global data to be used for discriminating character type;

FIG. 6(a) shows a structure of each FCB (Font control bank) to be used for managing fonts;

FIG. 6(b) shows an alignment structure of FCBs;

FIG. 7 shows a composition of each FCB in detail;

FIG. 8(a) shows a composition of a ring buffer for storing data of D-BANKs;

FIG. 8(b) shows a state wherein several D-BANKs are registered;

FIGS. 9(a), 9(b) and 9(c) show a manner for registering a new D-BANK;

FIG. 10(a) shows a composition of a VFCB (Virtual font control bank);

FIG. 10(b) shows an alignment structure of VFCBs;

FIG. 11 shows a composition of each VFCB in

FIG. 12 is a diagram showing various methods for selecting a font;

FIG. 13(a) is a composition of data to be used for selecting a font;

FIG. 13(b) is a composition of a font attribute defined by plural parameters;

FIGS. 14(a) and 14(b) is a flow chart of the main routine to be executed by CPU of the bit map controller;

FIG. 14 is a partial flow chart showing a variation of the main routine;

FIG. 15 is a flow chart of a subroutine for reading font attributes;

FIG. 16(a) is a flow chart of a subroutine for font status initial setting;

FIG. 16(b) is a partial flow chart showing a variation of the subroutine shown in FIG. 16(b);

FIG. 17 is a flow chart of a subroutine for font information registration;

FIG. 18 is a flow chart of a subroutine for font directory registration;

FIG. 19 is a flow chart of a subroutine for initial font selection;

FIG. 20 is a flow chart of a subroutine for font selection by logic font code;

FIG. 21 is a flow chart of a subroutine for setting a font cell;

FIG. 22 is a flow chart of a subroutine for font renewal;

FIG. 23 is a flow chart of a subroutine for VFCB registration;

FIG. 24 is a flow chart of a subroutine for reading down font pattern data;

FIGS. 25(a) and 25(b) are flow charts of a subroutine for font selection by slot and F-BANK Nos.;

FIG. 26 is a flow chart of a subroutine for font selection by font name;

FIG. 27 is a flow chart of a subroutine for font ID registration;

FIG. 28 is a flow chart of a subroutine for font selection by ID No.; and

FIG. 29 is a flow chart of a subroutine for altering virtual font attributes.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

(a) Composition of the electro-photographic printer

FIG. 1 shows a block diagram of an electro-photographic printer system to which the present invention is applied.

Data sent from an external data processor 1 such as a host computer are stored in a file buffer 2 once in order to improve through-put of the external data processor 1 and stored data are outputted from the file buffer 2 to a printing system 10.

The printing system 10 is comprised of a data processor 3 of bit map type, a print engine 4 with use of an electro-photographic processor and a laser means and optional apparatuses such as an external paper supplying unit 5 and a sorter 6.

FIG. 2 shows a schematic block diagram of the data processor 3 of bit map type.

The data processor 3 (hereinafter referred to BMU) is comprised of a bit map controller 30 (hereinafter referred to BMC), a RAM 32 for bit map (hereinafter referred to BM-RAM 32, a bit map writer 31 for imaging characters on BM-RAM 3 and font means 33. A font detecting sensor 339 is responsive to the font means 33 to detect the presence of a font cartridge. BMU 3 is connected to the print engine 4 by a bus B3 for control data and a bus B4 for image data.

The print engine 4 includes three controllers. The first one is an interface controller 40 (hereinafter referred to IFC) for executing processing of control data sent from BMC 30, control of an operation panel 44 and timing control for the print engine 4 through an internal bus B5. The second one is an electro-photographic controller 41 for controlling an electro-photographic processor 45 in accordance with data sent from IFC 40 through the internal bus B5. The third one is a print head controller 42 (hereinafter referred to PHC) controlling a semiconductor laser (not shown) and a polygon motor (not shown) of a print head 43 in accordance with information sent from IFC 40 through the internal bus B5 in order to write image data on a photoconductive drum provided in the electrophotographic processor 45 which is sent from BMW 31 through the internal bus B4. The external paper supply unit 5 and the sorter 6 are also controlled by IFC 40 through the internal bus B5.

The printer system 10 is so called laser printer of bit map type. Print data sent from the external data processor 1 are imaged as bit images on BM-RAM 32 of BMU 3 and bit images are outputted to the print engine 4. The print engine 4 drives the semiconductor laser to write those images as a latent image on the photoconductive drum and a toner image obtained by developing the latent image with toner is transferred onto a paper.

Data sent from the external data processor 1 includes codes for controlling the print format and setting modes of the print engine other than character codes.

BMU 3 analyzes protocols of these codes other than character codes and outputs commands for controlling the print format, passing a paper and altering modes of the optical apparatuses to the print engine 4.

The print engine 4 executes various control such as control of the electro-photographic system accompanied with the image control, timing control of a print paper and processing in synchronous with timing of feeding the print paper to the optional apparatus. The method for controlling the print engine 4 is substantially same to that of an electro-photographic copy machine except for control of the scanning system.

FIG. 3 shows a block diagram of BMC 30.

BMC 30 is comprised of some blocks interconnected by an internal bus B301. A CPU 301 (hereinafter referred to BM-CPU) forms a main part of BMC 30 which communicates with the external data processor 1 and/or the file buffer 2 through an interface 308 for the external data processor 1, transforms print data (code data) into bit images, controls BMW 31 through an interface 306 therefore and controls the print engine 4 through an interface 307 therefor. A system ROM (SYS-ROM) 302 memorizes programs for BM-CPU 301. A system RAM (SYS-RAM) 303 is an area for processing data and memorizing stacks and fundamental flags.

A register buffer (R-buffer) 304 is a buffer provided for communicating with the external apparatus such as the external data processor 1 and the file buffer 2 which enables to execute programs of BM-CPU 301 and communication with the external data processor 1 in asynchronous with each other.

A packet buffer (P-buffer) 305 memorizes data sent from the external data processor 1 as intermediate codes (hereinafter referred to packet codes) which are obtained by transforming data based on attributes of a selected font so as to make imaging bit images onto BM-RAM 32 easier.

The font means 33 provides memory area for interchangeable font cartridges (not shown) mounted. In each font cartridge, pattern data of fonts of eight kinds at the maximum can be stored, as will be explained later. The external data processor 1 selects a font among all fonts stored in respective font cartridges.

The font once selected can be changed to another one even in imaging characters and, also, it is not prohibited to interchange the font cartridge wherein the font used for imaging characters at the present is stored.

Although real imaging operation is done by BMW 31, it becomes necessary to calculate parameters such as internal addresses of pattern data in the selected font and writing addresses on BM-RAM 32. It takes a relatively long time. In order to speed up the processing, data of the next page is processed beforehand in printing bit images formed on BM-RAM 32 and processed data is stored in P-buffer 305. As P-buffer 305, it is desirable to use a first-in.multidot.first-out memory (FIFO).

A print engine interface 307 is an interface for the print engine 4 which communicates JOB information such as a number of prints and JOB control commands such as print command with an interface of the print engine 4 through the bus B3.

(b) Font management

(1) Composition of the font cartridge

FIG. 4 shows a composition of a font cartridge inserted in a slot. Each font cartridge is comprised of eight banks from F-BANK 0 to F-BANK 7 which is comprised of a ROM or RAM. Font pattern data of each font is stored in one or more banks. Since, for example, font pattern data of a font of Chinese characters (Kanji) has a large volume, two or more banks are assigned to memorize font pattern data. However, it is prohibited to store font pattern data belonging to two or more fonts of different kinds in one bank. Also, it is prohibited to store font pattern data belonging to one font extending over two or more slots.

As shown in FIG. 4, in the No. 1 slot, four kinds of fonts FONT 1, FONT 2, FONT 3 and FONT 4 are memorized in banks F-BANK 0, F-BANKs 1 and 2, F- BANK 3 and F-BANKs 4 to 6, respectively. The last bank F-BANK 7 is empty. To respective fonts FONT 1 to FONT 4, internal logic codes 0 to 3 and F-BANK NUMBERS 0, 1, 3 and 4 indicating respective numbers of top F-BANKs from which fonts start, respectively.

In the No. 2 slot, FONT 5 is stored extending over three F-BANKs from 0 to 2 and FONT 6 is stored extending over F-BANKs from 3 to 7.

Other slots have an essentially same composition as No. 1 or No. 2 slot.

These slot No. and F-BANK No. are used for selecting a font, as will be explained later.

As font memories for the font cartridge, both of font ROM and rewritable font RAM are usable. The font RAM is used as memory for loading font pattern data from an external machine such as a host computer down thereto. There may be two cases with respect to the font RAM that font pattern data has been down loaded and that font pattern data has been unloaded. There are two types about the font RAM. One of them is of a type which is backed up with a back up power source and has an externally operable input switch. In this type, font pattern data once loaded down is maintained.

Another type does not have any back up means and therefore, font pattern data is cancelled when the power is switched off.

As will be explained later, the top byte of the font RAM is used as discrimination information. The font RAM, into which font pattern data is considered to be written according to information regarding the external input switch or font managing information (FCB), is registered as a loaded RAM.

Each font data is comprised of font global data, directory and individual dot patterns.

In the font global data, a font name of ASCII 6 is included. The font name is used for selection of a font, as will be explained later.

FIG. 5(a) shows a structure of a code which is included in the global data for discriminating character type. The code is comprised of eight bits from b0 to b7 and upper three bits (b.sub.7, b.sub.6, b.sub.5) are used to indicate a wide classification and lower five bits (b.sub.4, b.sub.3, b.sub.2, b.sub.1 and b.sub.0) are used to indicate a narrow classification. The wide classification is the most important discrimination information for management of fonts and, as an example, shown in the next table.

                  TABLE
    ______________________________________
    Wide Classification
                   Narrow Classification
    ______________________________________
    0              Alphabetical typewriter
    1              Alphabetical typewriter
    2              --
    3              --
    4              JIS KANJI code
    5              --
    6              for form overlay
    7              for down load
    ______________________________________
     *JIS (Japanese Industrial Standard)

                  TABLE 2
    ______________________________________
            Absolute level
    Nickname  -2       -1       0      +1    +2
    ______________________________________
    Style     Normal   Normal   Normal Italic
                                             Italic
    Width (Pitch)
              20       15       12     10     6
    Height     6        9       12     18    24
    Thickness Light    Light    Medium Bold  Extra
    (weight)                                 Bold
    ______________________________________

                                      TABLE 3
    __________________________________________________________________________
              Absolute level
    Nickname  -2   -1    0    +1    +2
    __________________________________________________________________________
    Emphasis
         Weight
              Light
                   Light Medium
                              Bold  Bold
         Pitch
              15   12    12   12    10
    Softness
         Type Normal
                   Italic
                         Normal
                              Italic
                                    Normal
         Kind Gothic
                   Gothic
                         Courier
                              Courier
                                    Times-
                                    roman
    Total
         Pitch
              20   15    12   10     6
    size Height
               6    9    12   18    24
    __________________________________________________________________________

• Inventors
  Morikawa, Takashi; Ikenoue, Yoshikazu;
• Assignee
  Minolta Camera Kabushiki Kaisha (Osaka, JP)
• Published
  Aug-25-1992
• Current US Classes:
  358/1.11
  400/70
  715/524
  715/542
• Application #
  598809
• International Classes
  G06F 015/40
• Field of Search
  364/518 364/519 340/735 340/790 400/72 400/172 400/279 395/110 395/150
• Examiner
  Harkcom; Gary V.
• Agent
  Burns, Doane, Swecker & Mathis
• US Patent References:
  3964591
  4234931
  4594674
  4660998
  4660999
  4686525
  4698677
  4763281
  4998210