JP2601800B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to an image forming apparatus for producing a negative or positive film for producing a printing original plate for offset printing, for example.

(Prior Art) In recent years, plate making printing technology has been greatly advanced with the development of electronics, and today, electronic plate making has become mainstream. In this electronic plate making, the density of an image of a document is photoelectrically converted, the electric signal is subjected to predetermined processing to change the intensity of light, the film (photosensitive material) is exposed, and the film is developed to develop a printing. This is to create a negative or positive film that is the basis of the original.

However, in such a method, the manufacturing process is very complicated, and the machine itself is large and therefore very expensive.

(Problems to be Solved by the Invention) As described above, in the conventional method of producing a film for producing a printing plate precursor, the production process is very complicated, and the machine itself is large-sized, and therefore very expensive. There is a disadvantage that there is.

In view of the above, the present invention has been made to eliminate the above-mentioned disadvantages, and it is an object of the present invention to provide a small-sized and inexpensive image forming apparatus capable of forming a film for printing original plate very easily while having a relatively simple configuration. Aim.

[Structure of the Invention] (Means and Action for Solving the Problems) The image forming apparatus of the present invention optically scans an original to read a plurality of types of color signals, and converts each obtained color signal into a plurality of images. When a color image forming mode is selected, a color image is formed on an image forming medium in accordance with the plurality of converted image forming signals, and when a printing original plate creation mode is selected, A single-color image is formed on an image forming medium in accordance with one of the plurality of converted image forming signals, whereby a film for preparing a printing original plate can be formed very easily.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIGS. 1 and 2 show, as an example of an image forming apparatus according to the present invention, a thermal transfer type color copying machine capable of selectively forming a film for multicolor color copying and a printing original plate. That is, reference numeral 1 denotes a copying machine main body, and an operation panel 2 is provided at a front portion of an upper surface of the main body 1. The left side of the main body 1 is a document scanning section 8 for scanning and reading a document set on a document table 7, and the right side is an image forming section 9. Reference numeral 10 denotes a document cover provided on the document table 7 so as to be freely opened and closed.

The document scanning unit 8 is configured as shown in FIGS. 3 and 4, for example. That is, the platen 7 is fixed to the main body 1, and reciprocates along the lower surface of the platen 7 in the direction of arrow a in the figure below the platen 7.
A scanner 11 for optically scanning and reading the document O set thereon is provided. The scanner 11 includes an illumination lamp 12 for illuminating the original O, a photoelectric converter 13 for receiving the reflected light from the original O, and an optical system for guiding the reflected light from the original O to the photoelectric converter 13.
14, and a carriage 15 that supports them. The photoelectric converter 13 photoelectrically converts the reflected light from the original O to convert the image of the original O into cyan, green,
It separates and outputs yellow (or red, green, and blue) light color signals, and is mainly composed of, for example, a CCD line image sensor. Carriage 15
Is guided by a guide rail 16 and a guide shaft 17 so as to be reciprocally movable in the direction of arrow a. A drive pulley 19 driven by a scanning motor (for example, a pulse motor) 18 capable of normal and reverse rotation is provided at one end of the guide shaft 17, and a driven pulley 20 is provided at the other end thereof. Timing belt 21 between 19 and 20
Has been passed. One point of the timing belt 21 is fixed to the carriage 15 via a fixing member 22. Thus, the carriage 15 moves linearly when the scanning motor 18 rotates forward or backward.

The image forming section 9 is configured, for example, as shown in FIG. That is, the platen 30 is disposed substantially at the center of the image forming section 9 and
A thermal head 31 is provided on the left side opposite to 30. The thermal head 31 is attached to a radiator 33 integrally formed on the rear end surface of the holder 32. Then, a ribbon cassette 35 containing a thermal transfer ink ribbon 34 as an image forming medium is detachably mounted via the holder 32, and the thermal transfer ink ribbon 34 is interposed between the thermal head 31 and the platen 30. Has become. As shown in FIG. 5, the ribbon cassette 35 is a thermal transfer ink ribbon.
34 has two parallel winding cores 36 and 37 around which both ends are wound, and a middle portion of the thermal transfer ink ribbon 34 is provided so as to be interposed between the platen 30 and the thermal head 31. The configuration is such that the case 38 is covered with the part exposed. When the ribbon cassette 35 is mounted, the cores 36 and 37 are connected to a drive shaft of a motor (not shown) via a drive force transmission mechanism (not shown), and are rotatably driven as necessary. Further, as shown in FIG. 1, the ribbon cassette 35 can be mounted on or removed from the holder 32 through an insertion / removal opening 39 formed on the right side surface of the main body 1. The insertion / removal opening 39 is provided with a lid 40 that can be opened and closed.

A sheet feeding roller 41 is provided at a lower right portion of the platen 30 so that sheets (or plastic films) P as an image forming medium accommodated in a sheet cassette 42 are taken out one by one. I have. The paper P picked up by the paper feed roller 41 is sent to a registration roller 43 disposed diagonally above and to the right of the paper feed roller 41, where the leading end of the paper P is aligned, and then directed to the platen 30 by the registration roller 43. And is wound around the platen 30 by the pressing rollers 44 and 45, thereby being accurately fed. Here, the paper feed cassette 42 is detachable from the front of the main body 1. Reference numeral 46 in FIG. 5 denotes a manual paper feeder for manually feeding the paper P.

The thermal head 31 presses the paper P against the platen 30 via the thermal transfer ink ribbon 34, and heats and melts the ink 47 as a coloring material on the thermal transfer ink ribbon 34 to form the paper P as shown in FIG. It is designed to transfer. As shown in FIGS. 6 and 7, for example, the thermal transfer ink ribbon 34 has yellow, magenta, cyan, and black ink portions 47 _Y , 47 _M , 47 _C , and 47 _B each having a width substantially equal to that of the paper P. After transferring one color at a time, the paper P is returned to the transfer start position, and is sequentially superimposed accurately.

The thermal transfer ink ribbon 34 is, for example, a color multi-color thermal transfer ink ribbon as shown in FIG. 7 described above, and a single color, for example, a black color, is used for forming a film for producing a printing original plate. A thermal transfer ink ribbon is used.

At the time of color copying, the paper P is reciprocated by the number of colors by the rotation of the platen 30, and the path of the paper P at that time is located on the lower surface of the discharge tray 48 that is inclined and protruded above the main body 1. Are guided along first and second guide plates 49 and 50 sequentially disposed along the first and second guide plates. This is because the first and second distribution gates 51 and 5 provided between the platen 30 and the ends of the first and second guide plates 49 and 50, respectively.
Done by two. That is, first, the paper feed cassette 42
The sheet P taken out of the printer is supplied to the registration roller 43 and the first
It is transported through the portion of the distribution gate 51 and its tip is wound around the platen 30. Next, platen 30
The paper P is transported at a constant speed by being rotated forward by a pulse motor (not shown) or the like.
The heating elements (not shown) of the thermal head 31 arranged in the form of line dots along the axial direction generate heat in accordance with the print signal, whereby the ink 47 of the thermal transfer ink ribbon 34 is transferred onto the paper P. Then, the leading end of the sheet P passing through the platen 30 is sent to a first guide plate 49 provided along the lower surface of the sheet discharge tray 48 by the second sorting gate 52 located at the solid line position at this time. In this way, when the transfer to the ink 47 of one color is completed, the sheet P is fed backward by the reverse rotation of the platen 30 and returned to the transfer start position. At this time, the rear end of the sheet P is fed onto the second guide plate 50 provided along the lower surface of the first guide plate 49 by the first sorting gate 51 which is rotated and displaced to the position indicated by the two-dot chain line. In this way, a plurality of colors are transferred by reciprocating the paper P a plurality of times. Finally, the paper P on which the transfer to the inks 47 of all colors has been completed is guided to the paper discharge roller 53 by the second distribution gate 52 which is rotated and displaced to the position indicated by the two-dot chain line at this time. Output tray
What is discharged on the 48.

When the thermal transfer ink ribbon 34 of a single color (black) is used (at the time of forming a printing original plate forming film), the transfer is performed only once, and the paper P is not reciprocated. The paper is directly discharged onto the paper discharge tray 48.

FIG. 8 shows the operation panel 2, and a mode key for selecting a normal mode (color copying mode) and a single color mode.
61, a color selection key 62 for specifying a color in the single-color mode, a numeric keypad 63 for setting the number of copies, a clear key 64 for clearing the set number of copies, a copy key 65 for starting a copy operation,
A number display 66 for displaying the number of copies and the like, a status display section 67 for displaying an operation status and the like are provided. The color selection key 62 is, for example, a Y key 68 for designating yellow (Y),
It is composed of an M key 69 for designating magenta (M), a C key 70 for designating cyan (C), and a B key 71 for designating black (B).

FIG. 9 schematically shows the overall control system, which includes a main control unit 81, a first sub-control unit 82, and a second sub-control unit 83. The main control unit 81 includes the operation panel 2, the correction circuit 8,
4. Connected to the luminance / color difference separation circuit 85, image quality improvement circuit 86, color signal conversion circuit 87, binarization circuit 88, first sub-control unit 82 and second sub-control unit 83, and controls these. First
The sub-control unit 82 is connected to the light source control unit 89, the motor drive unit 90, the photoelectric converter 13, the A / D converter 91, and the resolution conversion unit 92, and controls these. The light intensity control unit 89
It is connected to the illumination lamp 12 and controls its light amount.
The motor drive unit 90 is connected to the scanning motor 18 and drives the same. The second sub-control unit 83 includes a thermal head temperature control unit 93, the thermal head 31, and various detection switches.
It is connected to 94 and the drive unit 95, respectively, and controls these controls. The drive unit 95 is connected to a drive system 96 such as a motor and a solenoid, and drives the drive system 96.

The signal flow in FIG. 9 in such a configuration will be described. The reflected light of the light emitted from the illumination lamp 12 onto the document forms an image on the photoelectric converter 13. The photoelectric converter 13 is
This light is separated into analog color signals of cyan (C), green (G), and yellow (Y), and sent to the A / D converter 91. The A / D converter 91 converts each analog color signal into a digital signal, and sends the digital signal to the resolution converter 92. The resolution conversion unit 92 is provided for determining the resolution of the photoelectric converter 13 and the thermal head.
The resolution is converted to match the resolution of 31 and the result is sent to the correction circuit 84. The correction circuit 84 performs a correction process on each of the C, G, and Y color signals sent from the resolution conversion unit 92 to correct the variation of the photoelectric converter 13, and sends the result to the luminance / color difference separation circuit 85. . Luminance / color difference separation circuit
85 performs various arithmetic processing on each of the C, G, and Y color signals sent from the correction circuit 84, and converts the signals into a luminance signal (I), a color difference signal 1 (C1), and a color difference signal 2 (C2). It is separated and sent to the image quality improvement circuit 86. The image quality improvement circuit 86 is a luminance / color difference separation circuit.
Luminance signal, color difference signal 1, color difference signal 2 sent from 85
Is analyzed, image enhancement processing such as edge enhancement and character identification is performed, and sent to the color signal conversion circuit 87. Color signal conversion circuit 87
Performs color conversion based on the luminance signal, chrominance signal 1 and chrominance signal 2 that have been subjected to image quality improvement processing, and performs yellow (Y), magenta (M), cyan (C), and black (B) printing. Of the three primary colors (Y, M, C) plus B], and sends it to the binarization circuit 88. The binarization circuit 88 performs gradation conversion, that is, binarization, on the color signal (any one of Y, M, C, and B) sent from the color signal conversion circuit 87. A value signal is sent to the thermal head temperature controller 93. The thermal head temperature controller 93 sends a print signal to the thermal head 31 based on the binary signal sent from the binary circuit 88. The thermal head 31 performs printing (that is, image formation) according to the print signal.

Here, the color signal conversion circuit 87 will be described in more detail with reference to FIG. Luminance signal (I), color difference signal 1 (C1), color difference signal 2 (C2) sent from image quality improvement circuit 86
Are sent to the color signal conversion circuit 87, where
Any one of the Y, M, C, and B color signals is converted to a binarization circuit 88.
The selection of the Y, M, C, and B color signals is performed by the main control unit 81. That is, as shown in the following table, the main control unit 81 selects the Y, M, C, B color signals sent to the binarization circuit 88 according to the combination of the signals a, b. The selection of the color signals is automatically and sequentially selected in the normal color copying mode (for example, in the order of Y → M → C → B), and in the single color mode, according to the operation of the color selection key 62. The corresponding color signal is selected.

Next, the operation will be described with reference to the flowchart shown in FIG. First, in step S1, it is determined whether or not the monochrome mode has been selected. If the monochrome mode has not been selected, a normal color copying mode is set, and the process proceeds to step S2.
Proceed to. In step S2, it is determined whether or not the copy key 65 has been turned on, and if not, the process returns to step S1, and
If it is turned on, the process proceeds to step S3. In step S3, an image forming operation is performed. That is, in this case, since the mode is the color copying mode, color copying (image formation) using the thermal transfer ink ribbons of a plurality of colors is performed by the above-described operation.

If it is determined in step S1 that the monochrome mode has been selected, the process proceeds to step S4 since the printing original plate creation film creation mode has been selected. In step S4, as an initial setting, the color signal conversion circuit 87 is instructed to convert to yellow (Y) color signals, and the process proceeds to step S5. In step S5, the color selection key 62
It is determined whether or not is turned on, and if not, the process proceeds to step S6. In step S6, it is determined whether or not the copy key 65 has been turned on.
To step S3 if it is turned on. Steps
In S3, an image forming operation is performed. That is, in this case, since the printing mode of the printing original plate forming film is set, the above-described operation performs the single-color copying (image formation) using the black thermal transfer ink ribbon. In this case, the color signal conversion circuit
Since the conversion to the yellow (Y) color signal is commanded to 87, image formation is performed on the yellow component of the image of the document. In this case, it is assumed that a thermal transfer ink ribbon of a single black color is set in advance, and a plastic film is set as the paper P, for example. As a result, a film for producing a printing original plate for the yellow component of the image of the document is obtained.

If the color selection key 62 has been turned on in step S5, the process proceeds to step S7. In step S7, it is determined whether or not the Y key 68 has been turned on. If the Y key 68 has been turned on, the process proceeds to step S8. In step S8, the color signal conversion circuit 87 is instructed to convert the color signal into yellow (Y) color signal.
It returns to step S5. Here, if the copy key 65 is turned on, the process proceeds to step S3 to perform an image forming operation. in this case,
Since the color signal conversion circuit 87 is instructed to convert the yellow (Y) color signal, the image formation of the yellow component of the image of the document is performed. As a result, a film for producing a printing original plate for the yellow component of the image of the document is obtained.

If it is determined in step S7 that the Y key 68 has not been turned on, the process proceeds to step S9. In step S9, it is determined whether or not the M key 69 has been turned on. If the M key 69 has been turned on, the process proceeds to step S10. In step S10, the color signal conversion circuit 87 is instructed to convert the color signal of magenta (M) into a color signal.
It returns to step S5. Here, if the copy key 65 is turned on, the process proceeds to step S3 to perform an image forming operation. in this case,
Since the conversion to the magenta (M) color signal is instructed to the color signal conversion circuit 87, an image is formed on the image magenta component of the document. As a result, a film for preparing a printing original for the magenta component of the image of the original is obtained.

If the M key 69 has not been turned on in step S9, the process proceeds to step S11. In step S11, it is determined whether or not the C key 70 has been turned on. If the C key 70 has been turned on, the process proceeds to step S12. In step S12, the color signal conversion circuit 87 is instructed to convert to a cyan (C) color signal.
It returns to step S5. Here, if the copy key 65 is turned on, the process proceeds to step S3 to perform an image forming operation. in this case,
Since the color signal conversion circuit 87 is instructed to convert the color signal into a cyan (C) color signal, the image formation of the cyan component of the image of the document is performed. As a result, a film for preparing a printing original for the cyan component of the image of the document is obtained.

If the C key 70 has not been turned on in step S11, the process proceeds to step S13. In step S13, the B key 71
Is turned on, the color signal conversion circuit 87 is instructed to convert the color signal into black (B) color signal, and the process returns to step S5. Here, if the copy key 65 is turned on, the process proceeds to step S3 to perform an image forming operation. In this case, the color signal conversion circuit
Since the instruction to convert the color signal into black (B) color signal is given to 87, the image formation for the black component of the image of the original is performed. As a result, a film for preparing a printing original for the black component of the image of the original is obtained.

In this manner, the original is optically scanned and read as three types of color signals of cyan, green and yellow, and these three signals are read.
The color signals of various types are converted into yellow, magenta, cyan, and black image forming signals, and according to one of these image forming signals, a black-color thermal transfer ink ribbon is used on a plastic film or paper. An image is formed. As a result, a film for preparing a printing original plate can be formed very easily with a relatively simple configuration, and can be realized in a small size and at low cost.

[Effects of the Invention] As described in detail above, according to the present invention, it is possible to form a full-color image and to relatively easily and inexpensively prepare a film for producing a printing original plate. For example, when creating a light print such as a flyer, special high image quality is not required, and rather, it is strongly required to easily and cheaply create and print an original, but the structure of the present invention Such a request can be appropriately met.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view for explaining one embodiment of the present invention, and FIG. 1 is a schematic perspective view showing the entire structure with a part cut away, and FIG.
FIG. 3 is an external perspective view schematically showing the overall configuration, FIG. 3 is a side view schematically showing the configuration of the document scanning section, FIG. 4 is a perspective view showing a scanner moving mechanism of the document scanning section, and FIG. 5 is a longitudinal side view schematically showing the configuration of the image forming unit, FIG. 6 is a perspective view for explaining a transfer operation state, FIG. 7 is a plan view showing the configuration of a thermal transfer ink ribbon, and FIG. FIG. 9 is a block diagram schematically showing an overall control system, FIG. 10 is a block diagram for explaining a color signal conversion circuit in detail, and FIG. 11 is a diagram for explaining operation. It is a flowchart of FIG. O: Original, P: Paper (image forming medium), 8: Original scanning unit, 9: Image forming unit, 11: Scanner, 31: Thermal head, 34: Thermal transfer ink ribbon (image Forming medium), 62: color selection key, 81: main control unit, 82, 83 ...
Sub-control unit, 87: color signal conversion circuit, 93: thermal head temperature control unit.

Claims (1)

(57) [Claims] A scanning means for optically reading a color image, decomposing the color image into a plurality of types of color signals, and outputting the color signals;
A color conversion unit for converting each of magenta and cyan image forming signals; a selecting unit for selectively selecting a color image forming mode and a printing original plate forming mode; and a case where the color image forming mode is selected by the selecting unit. , Yellow converted by the color conversion means,
A color image is formed on an image forming medium using all the image forming signals of the magenta and cyan image forming signals, and when the printing original plate creation mode is selected by the selecting unit, the color image is converted by the color converting unit. Image forming means for forming a single-color image on an image forming medium using only an image forming signal corresponding to one of yellow, magenta, and cyan thus obtained. apparatus.