JPS6348077A - Image forming device - Google Patents

Abstract

PURPOSE:To produce a film for printing original plate production easily by forming a monochromatic or multichromatic image on an image forming medium by using a monochromatic or multichromatic image forming medium corresponding to one or plural ones of image forming signals of plural colors. CONSTITUTION:An original is optically scanned, and is read as color signals of cyan, green, and yellow, which are converted to four colors., image forming signals of yellow, magenta, cyan, and black. Corresponding to one of these four colors among image forming signals or to all of them sequentially outputted, an image is formed on a plastic film or a paper P by using a thermal transfer ink ribbon 34 of black color only. By changing over the mode, a multichromatic image is formed on the paper correspponding to the image forming signals of four colors by using thermal transfer ink ribbon of plural colors. As a result, the titled device can be used as a color copying machine other than for the production of films for printing plate production.

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention (Industrial Application Field) The present invention relates to an image forming method for forming an image of a color-separated original document, which is required when creating a printing original plate for offset printing, for example. The present invention relates to an image forming apparatus.

(Prior Art) Recently, plate making and printing technology has made great progress with the development of electronics, and electronic plate making has become mainstream today. This electronic plate making photoelectrically converts the shading of the original image,
By performing certain processing on the electrical signal, the intensity of the light is changed, exposing the film (photosensitive material), and developing it to create negative or positive film, which is the basis of the original printing plate. .

However, in such a method, the manufacturing process is very complicated, and the machine itself is large and therefore very expensive. In addition, conventional machines were dedicated to creating original plates and could not be used for other purposes.

Furthermore, in order to ensure reliable alignment with the film used to create printing master plates for each color, alignment marks (register marks) are pasted by hand onto each film used to create printing master plates. It was getting worse. For this reason, the operability was poor, and there was also a possibility that positional deviation would occur.

(Problems to be Solved by the Invention) As mentioned above, in the conventional method of creating a film for printing original plates, the manufacturing process is very complicated, and the machine itself is large, so it is very expensive. It has the disadvantage that it is not suitable for other purposes. Further, there are also disadvantages in that the marking of alignment marks on the film for producing the printing original plate is difficult to operate, and there is a possibility that misalignment may occur.

Therefore, the present invention eliminates the above-mentioned drawbacks, and makes it possible to create a film for printing original plate very easily without using the complicated production process as in the past, and also to realize it in a small size and at low cost. It is an object of the present invention to provide an image forming apparatus which can be used not only for producing a film for producing a printing original plate but also for example as a color copying machine, and which can also easily and accurately apply marks for printing alignment.

[Structure of the Invention] (Means and Effects for Solving the Problems) The image forming apparatus of the present invention optically scans a document to read it as a plurality of color signals, and converts each obtained color signal into a plurality of color signals. image forming signals, and in response to one or more of the plurality of color image forming signals, a single color or a plurality of color images are printed on the imaged medium using a single color or a plurality of color image forming media. It forms a color image, which makes it very easy to create a film for printing original plates, and it can also be used, for example, as a color copying machine. In addition, an image is formed on the image forming medium in accordance with the pattern of the alignment mark for one of the plurality of color image forming signals, and this allows the printing position to be set when creating a film for creating a printing original plate. Marks for alignment can be easily and accurately applied.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIGS. 2 and 3 show a thermal transfer color copying machine that is capable of selectively producing multicolor color copies and producing a printing original plate production film (block copy) as an example of the image forming apparatus according to the present invention. It is. That is, 1 is a main body of a copying machine, and an operation panel 2 is provided at the front of the upper surface of the main body 1. The left side of the main body 1 is a document scanning section 8 that scans and reads a document set on a document table 7, and the right side is an image forming section. Note that 10 is a document cover provided on the document table 7 so as to be openable and closable.

The document scanning section 8 is configured as shown in FIGS. 4 and 5, for example. That is, the document table 7 is fixed to the main body 1, and the document O set on the document table 7 is placed below the document table 7 by reciprocating along the lower surface thereof in the direction of arrow a in the figure. A scanner 11 is provided for optical scanning and reading. The scanner 11 includes an illumination lamp 12 that illuminates the original O, a photoelectric converter 13 that receives reflected light from the original O, an optical system 14 that guides the reflected light from the original 0 to the photoelectric converter 13, and supports these. Carriage 15
Consisted of. The photoelectric converter 13 photoelectrically converts the light reflected from the original O to separate and output the image of the original 0 as cyan, green, and yellow (or red, green, and blue) light color signals. It is mainly composed of a CCDCD beline image sensor. As shown in FIG. 5, the carriage 15 is guided by a guide rail 16 and a guide shaft 17 so as to be able to reciprocate in the direction of arrow a. At one end of the guide shaft 17, a scanning motor (for example, a pulse motor) 18 capable of forward and reverse rotation is mounted.
A drive pulley 19 is driven by a drive pulley 19, and a driven pulley 20 is disposed at the other end of the drive pulley 19.
A timing belt 21 is stretched between 9° and 20°. One point of the timing belt 21 is fixed to the carriage 15 via a fixing member 22.

This allows the carriage 15 to move linearly by rotating the scanning motor 18 in the forward or reverse direction.

The image forming section 9 is configured as shown in FIG. 6, for example. That is, a platen 30 is disposed approximately at the center of the image forming section 9, and a thermal head 31 is disposed on the left side facing the platen 30. The thermal head 31 is attached to a heat radiator 33 that is integrally formed on the rear end surface of the holder 32.

A ribbon cassette 35 containing a thermal transfer ink ribbon 34 as an image forming medium is detachably attached via a holder 32, and the thermal transfer ink ribbon 34 is interposed between the thermal head 31 and the platen 30. It has become. As shown in FIG. 6, the ribbon cassette 35 has two parallel winding cores 36 and 37 around which both ends of the thermal transfer ink ribbon 34 are wound, and a midway portion of the thermal transfer ink ribbon 34 is wound around the cores 36 and 37. In order to be interposed between the platen 30 and the thermal head 31, it is covered with a case 38 with a part thereof exposed. The winding cores 36 and 37 are fixed when the ribbon cassette/soto 35 is attached.
It is connected to a drive shaft of a motor (not shown) via a driving force transmission mechanism (not shown), and is rotated as necessary. Further, as shown in FIG. 2, the ribbon cassette 35 can be inserted into or removed from the holder 32 through an insertion/removal port 39 formed on the right side of the main body 1. Note that the insertion/removal port 39 has a lid 40 that can be opened and closed freely.
is provided.

A paper feed roller 41 is provided diagonally below the right side of the platen 30, and a paper (or plastic film) as an image forming medium housed in a paper feed cassette 42 is provided.
P is taken out one by one. Paper feed roller 41
The paper P taken out is sent to the registration rollers 43 disposed diagonally above and to the right of the paper feed roller 41, and its leading edge is aligned, and then transported by the registration rollers 43 toward the platen 30. The pressing is performed by wrapping the platen 30 around the rollers 44 and 45, thereby allowing accurate feeding. Here, the paper feed cassette 42 is detachable from the front of the main body 1.

Incidentally, numeral 46 in FIG. 6 is a half-length sheet feeding device for manually feeding the sheet P.

The thermal head 31 presses the paper P against the platen 30 via the thermal transfer ink ribbon 34, and as shown in FIG. It is designed to be transcribed. As shown in FIGS. 7 and 8, the thermal transfer ink ribbon 34 has a width approximately equal to that of the paper P and is yellow.

Magenta, cyan, and black ink portions 47Y.

47M, 47C, and 47s are sequentially stacked one on top of the other, and after transferring one color at a time, the paper P is returned to the transfer starting position, and the sheets are accurately stacked one after another. Note that the thermal transfer ink ribbon 34 may not have the black ink portion 47B, and in that case, approximately black can be produced by overlapping the three colors of yellow, magenta, and cyan.

Note that during color copying, each ink portion 47Y, 47. .

Image formation is performed using 47c and 47B. On the other hand, when creating a film for printing original plates, a solid black thermal transfer ink ribbon, for example, is used as the thermal transfer ink ribbon 34 to form an image. In this case, it is not necessary to use a solid black thermal transfer ink ribbon, and the image may be formed using the black ink portion 47B of the thermal transfer ink ribbon 34.

During color copying, the paper P is reciprocated by the number of colors by the rotation of the platen 30, but the path of the paper P at this time is to the bottom surface of the paper output tray 48 which is provided on the main body 1 at an angle. The 1st. 2nd information board 49.50
be led upwards. This includes the platen 30 and the first. The first guide plates 49 and 50 are respectively provided between the ends of the second guide plates 49 and 50.
This is done by the second distribution gates 51, 52. That is, first, the paper P taken out from the paper feed cassette 42 is transferred through the registration rollers 43 and the first distribution gate 51, and its leading end is wound around the platen 30. Next, the platen 30 is rotated in the forward direction by a pulse motor (not shown) to transport the paper P at a constant speed, and the heating elements of the thermal head 31 arranged in a line tread along the axial direction of the platen 30 (not shown) generates heat in response to the print signal, and thereby the ink 47 of the thermal transfer ink ribbon 34 is transferred onto the paper P. Then, the leading edge of the paper P that has passed through the platen 30 is transferred to the second sorting gate 52 located at the solid line position.
Accordingly, the first
You will be sent up four guide boards. In this way, when the transfer of ink 47 of one color is completed, the platen 30 is rotated in the opposite direction, so that the paper P is reversely transported and returned to the transfer starting position. At this time, the rear end portion of the paper P is sent onto the second guide plate 50 provided along the lower surface of the four first guide plates by the first distribution gate 51 which is rotationally displaced to the position shown by the two-dot chain line. In this way, a plurality of colors are transferred by moving the paper P back and forth several times. Finally, the paper P on which the transfer of ink 47 of all colors has been completed is transferred to the second distribution gate 52 which is rotationally displaced to the position indicated by the two-dot chain line.
The paper is guided to the paper ejection roller 53 by the paper ejection roller 53, and is ejected onto the paper ejection tray 48.

Note that when forming an image using a solid black thermal transfer ink ribbon, that is, when creating a film for creating a printing plate, the transfer is performed only once, and the paper P is not moved back and forth, and the paper after the transfer is completed. P is discharged onto the paper discharge tray 48 as it is.

FIG. 9 shows the operation panel 2, in which a mode key 61 is used to select between normal mode (color copying mode) and monochrome mode (film production mode for producing printing master plates).
, a color selection key 62 for specifying the color in single color mode, a numeric keypad 63 for setting the number of copies, etc., a clear key 64 for clearing the set number of copies, etc., a copy key 65 for starting the copying operation, and a numeric display for displaying the number of copies, etc. A status display section 67 for displaying a device 66, an operating state, etc. is provided. The color selection keys 62 include, for example, a Y key 68 for specifying yellow (Y), an M key 69 for specifying magenta (M),
It is composed of a C key 70 for specifying cyan (C), a B key 71 for specifying black (B), and a batch print key 72 for specifying sequential output of each of the above colors.

FIG. 1 schematically shows the overall control system, which includes a main control section 81, a first sub-control section 82, and a second sub-control section 83. The main control unit 81 includes the operation panel 2, a correction circuit 84, a luminance/color difference separation circuit 85, an image quality improvement circuit 86,
The color signal conversion circuit 87 is connected to a binarization circuit 88, an alignment mark (register mark) generation circuit 97, a first sub-control section 82, and a second sub-control section 83, and controls these. The first sub-control unit 82 includes a light source control unit 89, a motor drive unit 90, the photoelectric converter 13, and an A/D converter 91.
and a resolution converting section 92, respectively, and manage these controls. The light amount control section 89 is connected to the illumination lamp 12 and controls the light amount thereof. A motor drive unit 90 is connected to the scanning motor 18 and drives it. The second sub-control unit 83 includes a thermal head temperature control unit 93
, the thermal head 31, various detection switches 94, and a drive unit 95, and controls these. 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 main control unit 81 operates using a mode key 61 in the operation panel 2.
Therefore, when the single color mode is selected, a mark adding signal (“1” signal) is output to the alignment mark generation circuit 97.

The flow of signals in FIG. 1 in such a configuration will be explained. The reflected light of the light irradiated onto the original from the illumination lamp 12 forms an image on the photoelectric converter 13 . Photoelectric converter 13
This light is cyan (C).

The signal is separated into green (G) and yellow (Y) analog color signals and sent to the A/D converter 91. The A/D converter 91 converts each analog color signal into a digital signal and sends it to the resolution converter 92. The resolution conversion unit 92
Resolution conversion is performed to match the resolution of the photoelectric converter 13 and the resolution of the thermal head 31, and the result is sent to the correction circuit 84. The correction circuit 84 includes a resolution converter 92
A correction process is performed on each of the C, G, and Y color signals sent from the photoelectric converter 13 to correct for variations in the photoelectric converter 13.
The result is sent to the luminance/color difference separation circuit 85. The luminance color difference separation circuit 85 receives the C, G, and Y signals sent from the correction circuit 84.
Various calculation processes are performed on each color signal of the luminance signal (I
), color difference signal 1 (C1), and color difference signal 2 (C2), and send them to the image quality improvement circuit 86. Image quality improvement circuit 8
6 analyzes the luminance signal, color difference signal 1, and color difference signal 2 sent from the luminance color difference separation circuit 85, performs image improvement processing such as edge emphasis and character identification, and converts the luminance signal to the color signal conversion circuit 87.
send to The color signal conversion circuit 87 performs color conversion based on the luminance signal, color difference signal 1, and color difference signal 2, which have been subjected to image quality improvement processing, to produce yellow (Y).

It is converted into a color signal of one of magenta (M), cyan (C), and black (B) [the three primary colors (Y, M, C) plus B during printing] and sent to the binarization circuit 88. Binarization circuit 8
8 is a color signal (Y
, M, C, B),
That is, it is binarized and the binarized signal is sent to the alignment mark generation circuit (generating means) 97. The alignment mark generation circuit 97 generates print alignment marks A in the binary signal sent from the binarization circuit 88 in response to the mark addition signal (“1” signal) from the main control unit 81. Either the pattern is given and sent to the thermal head temperature control unit 93, or the binary signal sent from the binarization circuit 88 is sent as it is to the thermal head temperature control unit without the pattern of print alignment mark A being given. Send to 93. The thermal head temperature control section 93 sends a print signal to the thermal head 31 based on the binary signal sent from the alignment mark generation circuit 97. The thermal head 31 performs printing (that is, image formation) according to this print signal.

Here, the color signal conversion circuit 87 will be explained in more detail with reference to FIG. Luminance signal (I), color difference signal 1 (C1), and color difference signal 2 sent from the image quality improvement circuit 86
Each signal (C2) is sent to the color signal conversion circuit 87, where Y, M.

A binarization circuit 88 converts one of the color signals of C and B.
I am sending them to Y, M, and C.

The selection of the B color signal is performed by the main control section 81.

That is, as shown in the table below, the main control section 81 receives the signal a.
, b are sent to the binarization circuit 88 by the combination of Y, M
, C, and B color signals are selected. Note that the above color signals are automatically selected sequentially (for example, in the order of Y-M-C-B) in the normal color copy mode, and in accordance with the operation of the color selection key 62 in the monochrome mode. The corresponding color signal is selected.

Further, the alignment mark generation circuit 97 will be explained in more detail with reference to FIG. That is, a horizontal counter 100 counts up in response to a data synchronization signal (DCLK) from the main control section 81 and clears it in response to a line synchronization signal (HSYNC), and the main control section 81
A vertical counter 101 that counts up in response to a line synchronization signal (HSYNC) from and cleared in response to a page synchronization signal (PSYNC), a count value from the horizontal counter 100, and a pattern selection signal from an output terminal 103a of the ROM 103. The ROM 102 outputs an address signal corresponding to the count value from the vertical counter 100 from the output terminal 102a (HD 1), 102b (HD2), and the output terminal 103a outputs an address signal corresponding to the count value from the vertical counter 100.
(VDI), 103b ROM output from (VD2)
103, an AND circuit 104 that takes an AND between the horizontal mark signal supplied from the output end 102a and the vertical mark signal supplied from the output end 103b; an AND circuit 105 that takes an AND with the output of the AND circuit 104;
The output from this AND circuit 105 is the inverter circuit 10
6, the binarization circuit 8
a buffer 107 that outputs the binary signal (image data, RDAT) from 8 to the thermal head temperature control section 93;
, and a buffer 10 that outputs registration mark data (alignment mark data) from the output end 102b of the ROM 102 to the thermal head temperature control section 93 only when the output from the AND circuit 105 is supplied.
It is composed of 8.

A pattern of print alignment marks A is set in the ROM 102 and 103, and the relationship between each output and the data output to the thermal head temperature control section 93 is as shown in the table below.

Therefore, as shown in FIG. 12(a), the pattern of print alignment marks A is output corresponding to the four corners, and the image data from the binarization circuit 88 is used as it is for the rest of the image at the temperature of the thermal head. It is output to the control section 93. As a result, as shown in FIG. 12(b), print alignment marks A are printed at the four corners, and images are printed at the other corners.

Next, the operation will be explained with reference to the flowcharts shown in FIGS. 13(a) and 13(b). First, in step S1, it is determined whether or not the monochrome mode is selected. If the monochrome mode is not selected, it is the normal color copying mode, and the process proceeds to step S2. In step S2, a "0" signal as a reset signal is sent to the alignment mark generation circuit 9.
7 is output to the AND circuit 105, and the process proceeds to step S3.

In step S3, it is determined whether or not the copy key 65 is turned on. If it is not turned on, the process returns to step S1, and if it is turned on, the process goes to step S4.

In step S4, an image forming operation is performed. That is, in this case, since the mode is color copying, color copying (image formation) is performed using the thermal transfer ink ribbons 34 of a plurality of colors by the above-described operation.

In step S1, if the single color mode is selected, this is the mode for producing a film for producing a printing original plate, so the process advances to step S5. In step S5, the main control unit 81
outputs a "1" signal as a mark addition signal to the AND circuit 105 in the alignment mark generation circuit 97, and proceeds to step S6.

In step S6, the -batch printing flag is reset, and the process proceeds to step S7. In step S7, as an initial setting, the color signal conversion circuit 87 is commanded to convert the yellow (Y) color signal into a color signal, and the process proceeds to step S8.

In step S8, it is determined whether the -discard print key 72 has been turned on, and if it has not been turned on, the process proceeds to step SIO. If it is determined that the batch print key 72 is turned on in step 8, the - batch print flag is set, and the process proceeds to step S10. In step S10, the color selection key 6
2 is turned on, and if it is not turned on, the process proceeds to step Sll. In step Sll, it is determined whether the single color mode has been cleared by pressing the mode key 61. If it is determined that the mode has been cleared, the process returns to step 1; if not, the process proceeds to step 12. In step S12, it is determined whether or not the copy key 65 is turned on. If it is not turned on, the process returns to step S8, and if it is turned on, the process goes to step S21.

If the color selection key 62 is turned on in step S10, the process advances to step S13. In step S13, the batch printing flag is reset, and the process proceeds to step S14. In step S14, it is determined whether or not the Y key 68 is turned on. If the Y key 68 is turned on, step S14 is performed.
Proceed to step 15.

In step S15, the color signal conversion circuit 87
Y) to a color signal, and the process returns to step S8.

In step S14, if the Y key 68 is not turned on, the process advances to step S16. In step S16,
It is determined whether the M key 69 is turned on, and the M key 69 is turned on.
If it is turned on, the process advances to step S17. In step S17, the color signal conversion circuit 87 is commanded to convert hemagenta (M) into a color signal, and the process returns to step S8.

In step S16, if the M key 69 is not turned on, the process advances to step S18. In step S18,
It is determined whether or not the C key 70 is turned on, and the C key 70 is turned on.
If it is turned on, the process advances to step S19. In step S19, the color signal conversion circuit 87 is commanded to convert into a Hessian (C) color signal, and the process returns to step S8.

In step S18, if the C key 70 is not turned on, the process advances to step S20. In step S20,
It is determined that the B key 71 has been turned on, and the color signal conversion circuit 87 is commanded to convert the black (B) color signal, and the process returns to step S8.

In step 21, it is determined whether the batch printing flag is set, and if it is not set, step 22
Proceed to.

In step S22, an image forming operation is performed for a single color component. That is, since this is the mode for producing a film for producing a printing original plate, monochrome copying (image formation) using a monochrome thermal transfer ink ribbon is performed by the above-described operation.

In this case, when the color signal conversion circuit 87 is instructing to convert the yellow (Y) color signal into a color signal, image formation is performed for the yellow component of the image of the document, and the color signal of the color signal conversion circuit 87 is hemagenta (M). When commanding conversion to , image formation is performed on the magenta component of the original image,
When the color signal conversion circuit 87 is commanded to convert Hessian (C) to a color signal, image formation is performed for the cyan component of the image of the original, and the color signal conversion circuit 87 Hessian (B)
When instructing the conversion into a color signal, image formation is performed for the black component of the original image. In this case, it is assumed that a solid black thermal transfer ink ribbon is set in advance, and as the paper P, for example, a plastic film is set in advance.

As a result, different films for producing printing original plates can be obtained for the yellow component, magenta component, cyan component, or black component of the original image.

If it is determined in step 21 that the batch printing flag is set, the process proceeds to step 23.

In step 23, the color signal conversion circuit 87
) to a color signal, and the process proceeds to step 24. In step 24, image formation for the yellow component of the original image is performed on the first sheet of plastic film or paper, and the process proceeds to step 25.

In step 25, the color signal conversion circuit 87
) to a color signal, and the process proceeds to step 26. In step 26, image formation for the magenta component of the original image is performed on a second sheet of plastic film or paper, and the process proceeds to step 27.

In step 27, the color signal conversion circuit 87 converts the Hessian (C)
Then, the process proceeds to step 28. In step 28, image formation for the cyan component of the original image is performed on the third sheet of plastic film or paper, and the process advances to step 29.

In step 29, the color signal conversion circuit 87
) to a color signal, and the process proceeds to step 30. In step 30, image formation for the black component of the original image is performed on a fourth sheet of plastic film or paper.

The provision of print alignment marks A when performing an image forming operation for a single color component as described above will be described.

That is, in the monochrome mode, a mark addition signal, that is, a "1" signal from the main control section 81 is supplied to the AND circuit 105, and the gate of the AND circuit 105 is opened. In this state, the image signal of one component of the original is supplied bit by bit from the binarization circuit 88 to the buffer 107 and stored therein. At this time, the data synchronization signal (DCLK) and line synchronization signal (HSY
NC) is supplied to the counter 100, and the line synchronization signal (
HSYNC) and a page synchronization signal (PSYNC) are supplied to the counter 101.

As a result, when the image signal of the first column of the first line is supplied to the buffer 107, the counters 100 and 101 each count up.

According to the count value of the counter 101, a "1" signal is output as a pattern selection signal from the output end 103a of the ROM 103, and a "1" signal is output as a vertical mark signal from the output end 103b. Also, the counter 100
R according to the count value of R and the signal from the output terminal 103a.
The output end 102a of the OM 102 outputs a "1" signal as a horizontal mark signal, and the output end 102b outputs a "0" signal as register mark data.

This registration mark data is stored in buffer 108.

A "1" signal is output from the AND circuit 104 based on the vertical mark signal from the output end 103b and the horizontal mark signal from the output end 102a. The output of this AND circuit 104 is supplied to a buffer 108 via an AND circuit 105, and is also supplied to a buffer 107 via an AND circuit 105 and an inverter circuit 106.

Therefore, the registration mark data "0" signal stored in the buffer 108 is transmitted to the alignment mark generation circuit 9.
7 is supplied to the thermal head temperature control section 93. At this time, the buffer 107 is prohibited from outputting its stored data.

Thereafter, similarly to the above, registration mark data is output to the four corners of the image.

Therefore, when image formation is performed for one color component of a document image in monochrome mode, a pattern of print alignment marks A is output corresponding to the four corners, as shown in FIG. 12(a). Otherwise, the image data for one color component from the binarization circuit 88 is output as is to the thermal head temperature control section 93. As a result, Figure 12 (
b) +:: Print alignment marks A at the four corners as shown
is printed, and an image for one color component is also printed.

2, optically scan the original in cyan.

It is read as 38 types of color signals of green and yellow, and these 3 types of color signals are read as yellow and magenta.

It converts into four-color image forming signals of cyan and black, and prints a single-black thermal transfer ink ribbon according to one of these four-color image forming signals or four sequentially output image forming signals. It is used to form images on plastic film or paper. As a result, it is possible to create a film for printing original plates very easily, with a relatively simple structure, without using conventional complicated production processes such as exposure and development, and it is also small and inexpensive. can. Furthermore, by switching modes, images are formed on paper using thermal transfer ink ribbons of a plurality of colors in accordance with the image forming signals of the four colors. As a result, it can be used not only for producing films for printing original plates, but also as a color copying machine, which is very convenient.

In addition, marks for print alignment can be easily and accurately applied to the film (base plate) for producing a printing original plate.

In addition, in the above embodiment, the case where marks for print alignment are provided at the four corners has been described, but the present invention is not limited to this.
There may be one, or two or more. If there are two or more, reliable alignment is possible.

In addition, a mode key is provided on the operation panel, and the mode is switched using this mode key, but the present invention is not limited to this. The mode may be switched by.

Furthermore, instead of the mode key, a separately provided print alignment mark designation switch may be used to designate the marking.

[Effects of the Invention] As detailed above, according to the present invention, a film for producing a printing plate can be produced very easily without using the conventional complicated production process, and it can be realized in a small size and at a low cost. In addition to creating films for printing master plates, it can also be used, for example, as a color copying machine, and it is also possible to accurately mark the printing alignment on the film for printing master plates. An image forming apparatus can be provided.

[Brief explanation of the drawing]

The drawings are for explaining one embodiment of the present invention.
The figure is a block diagram schematically showing the overall control system.
The figure is a schematic perspective view with a part cut away to show the overall structure, FIG. 3 is an external perspective view schematically showing the overall structure, and FIG. 4 is a side view schematically showing the structure of the document scanning section. 5 is a perspective view showing the scanner moving mechanism of the document scanning section, FIG. 6 is a vertical side view schematically showing the structure of the image forming section, and FIG. 7 is a perspective view for explaining the transfer operation state. 8 is a plan view showing the configuration of the thermal transfer ink ribbon, FIG. 9 is a plan view of the operation panel, FIG. 10 is a block diagram for explaining the color signal conversion circuit in detail, and FIG. 11 is a positioning diagram. 12(a) is a diagram showing the relationship between image data and the pattern of print alignment marks; FIG.
FIG. 13B is a diagram showing the printing state of the image and the print alignment mark, and FIG. 13 is a flowchart for explaining the operation. 0... Original, P... Paper (image forming medium), 2.
...Operation panel, 8... Original scanning unit, 9... Image forming unit, 11... Scanner, 31... Thermal head,
34...Thermal transfer ink ribbon (image forming medium), 61
...Mode key (mode changeover switch), 62...
Color selection key, 63... Numeric keypad, 72...-discard print key, 81... Main control section, 82.83... Sub control section, 87... Color signal conversion circuit, 88... Binarization circuit,
93... Thermal head temperature control unit, 97... Alignment mark generation circuit (generating means), 100... Horizontal counter, 101... Vertical counter, 102.103
...ROM. 104.105...AND circuit, 106...Inverter circuit, 107.108...Buffer. Applicant's agent Patent attorney Takehiko Suzue Figure 4 Figure 5, Q6 Figure 7 Figure 47Y 47M 47C47B Figure 8 Figure 10

Claims (10)

[Claims] (1) a scanning means for optically scanning a document and reading it as multiple types of color signals; a color conversion means for converting each color signal obtained by the scanning means into image forming signals of multiple colors; Forming a single-color or multiple-color image on an image forming medium using a single-color or multiple-color image forming medium according to one or more of the obtained multiple-color image forming signals. an image forming means; a generating means for generating a pattern of print alignment marks; and when forming an image with the image forming means, the pattern of print alignment marks from the generating means is applied to form the image. An image forming apparatus characterized by comprising means for performing the following steps. (2) The image forming apparatus according to claim 1, further comprising a specifying means for specifying the provision of print alignment marks. (3) The image forming apparatus according to claim 2, wherein the designation means is a print alignment mark designation switch provided on the operation panel. (4) The image forming apparatus according to claim 1, wherein the plurality of types of color signals are cyan, green, and yellow, or three types of red, green, and blue. (5) Image forming signals of multiple colors include yellow, magenta,
Claim 1 characterized in that the four colors are cyan and black, or the three colors are yellow, magenta and cyan.
The image forming apparatus described in . (6) The single-color image forming medium is characterized by consisting of one color, black, and the multi-color image forming medium is characterized by consisting of four colors, yellow, magenta, cyan, and black, or three colors, yellow, magenta, and cyan. An image forming apparatus according to claim 1. (7) The image forming apparatus according to any one of claims 1 and 6, wherein the image forming medium is a thermal transfer ink ribbon. (8) The image forming apparatus according to claim 1, wherein the image forming medium is paper or a plastic film. (9) The image forming apparatus according to claim 1, wherein the image formed on the image forming medium is used for creating an original plate for offset printing. (10) The image forming apparatus according to claim 9, wherein the printing alignment mark is generated only when creating an original plate for offset printing.