JPS62253454A - Image-forming device - Google Patents

Abstract

PURPOSE:To prevent a platen from being contaminated, by forming images according to the size of an image-forming medium. CONSTITUTION:With a switch 67 turned OFF according to the passage of a paper fed through a feeding passage 68, counting is started. When blind feeding of the paper is further conducted and the switch 67 is turned ON, the counting is finished. The length of the paper is detected based on the count thus obtained, and the paper feed quantity (the number of feeding steps) corresponding to an image-forming range is determined. The paper blindly fed is reversely fed, and reading of image information is started under the condition where the leading end of the paper corresponds to a transfer starting position A. In correspondence with the image-forming range, such a control as not to form images based on the image information beyond the number of feeding steps for the paper being fed. An image-forming operation is conducted in the image-forming range of the paper. Accordingly, a platen 50 is not stained with an ink.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an image forming apparatus such as a thermal transfer color copying machine or a toner-based electronic copying machine.

(Conventional technology).

For example, in a thermal transfer color copying machine that uses thermal transfer ink ribbons of multiple colors to make color copies, an optical scanning device scans the original to read the image information of the original as a light color signal. The image information is converted into color information corresponding to each ink of the thermal transfer ink ribbon, and this color information of each ink is temporarily stored. The stored color information is sequentially read out, and the corresponding ink section of the thermal transfer ink ribbon is used to thermally transfer the ink to the paper using the thermal head according to the read color information, thereby sequentially transferring the ink one color at a time to the paper. (image formation) and color copying.

Furthermore, in electronic copying machines that copy original images using toner, by scanning the original with an optical scanning means, the image information of the original is transferred onto a photoreceptor drum, which serves as an image carrier, and which has been given a charge in advance. The image is formed to form an electrostatic latent image on the drum surface. This electrostatic latent image is made into a visible image by adhering toner, and the toner image is transferred (image formation) onto paper by the action of a charger, thereby performing copying.

Incidentally, in the copying machine having the above configuration, an image forming operation is performed on the paper based on the image information of the entire surface of the original, regardless of the size of the supplied (fed) paper. For this reason, when the image information for a fully exposed document is large compared to the paper size, in thermal transfer color copying machines, image information is also formed on the platen part that is outside the paper size. This has the disadvantage that the platen gets dirty due to the ink.

Furthermore, in electronic copying machines, image information is also formed on the photoreceptor drum part that is outside the size of the paper, and excess toner is cleaned, so the photoreceptor drum is removed. Although the drum does not become dirty, there is a drawback that toner on areas outside the paper size is wasted.

(Problems to be Solved by the Invention) The present invention avoids the disadvantages of the platen becoming dirty and toner being wasted, and forms an image according to the size of the image forming medium, thereby preventing the platen from becoming dirty. It is an object of the present invention to provide an image forming apparatus that can prevent such problems and eliminate wasteful consumption of toner.

[Structure of the Invention] (Means for Solving the Problems) The image forming apparatus of the present invention includes a detecting means for detecting the size of the image forming medium fed manually, and a detecting means for detecting the size of the image forming medium manually fed. and a control means for controlling the image forming range of the input image information according to the size of the image forming medium.

(Function) This invention detects the size of the image forming medium manually fed by the detection means, and uses input image information according to the size of the image forming medium detected by the detection means. The image forming range is controlled by a control means.

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

FIG. 2 shows the external appearance of a thermal transfer color copying machine as an example of an image forming apparatus, in which an image information reading device 2 is detachably provided on the upper surface of the main body 1 of the apparatus. The image information reading device 2 is provided with a document cover 3 that can be opened and closed freely, and a document table (not shown) made of transparent glass on which a document is placed is provided below the cover 3. . This image information reading device 2 optically scans the document set on the document table by reciprocating the scanner section (details will be described later) consisting of an exposure optical system along the lower surface of the document table. It converts optical information into electricity. The information converted by this image information reading device 2 is supplied to an image forming section 5 detachably provided on the right side of the device main body 1.
In this image forming section 5, an image is formed on paper as an image forming medium according to the converted information. An operation panel 6 is provided on the upper front side of the image forming unit 1'EB5. Further, on the front side of the image forming section 5, a guide section 11 for manually feeding (feeding) paper is provided.
11 is freely provided, and a paper discharge tray 12 is provided on the top surface of the paper tray 12 from which the paper after the transfer is discharged. moreover,
A paper feed cassette 13 for storing paper is provided in the main body 1 of the apparatus located below the image forming section 5 so as to be able to be taken in and out. Note that 8 is a door for attaching and detaching a thermal transfer ink ribbon as a transfer agent, which will be described later, to and from the main body 1 of the apparatus.

On the other hand, FIG. 3 shows the configuration of the image information reading device 2. As shown in FIG. Two light sources 23 are arranged in parallel on the carriage 22 constituting the scanner section 21.
Two lenses 24 are arranged in an inverted V shape between each other. A photoelectric converter 25 made of a color CD is provided at the lower end of the lens 24. Said carriage 2
2 has one end slidably inserted into the guide shaft 26 and attached to a so-called timing belt (belt with 6i) 27 stretched along the guide shaft 26. This timing belt 27 is driven by a pulse motor 28. That is, the timing belt 27 is connected to the motor pulley P! provided on the rotating shaft of the pulse motor 28. The timing belt 27 is stretched between the timing belt 27 and the idle pulley P2, and the scanner section 21 is moved in accordance with the movement of the timing belt 27 as indicated by the arrow a in the figure.

It is moved in direction b. In addition, 29 is the photoelectric converter 25
an A/D conversion unit that converts the output signal of the
Reference numeral 30 converts the power output from the inverter 31 into the light source 2.
3, and also supplies the output signal of the A/D converter 29 to the image forming unit 5.

FIG. 4 shows the operation panel 6. As shown in FIG.

This operation panel 6 includes a print key 41 for instructing the start of printing (image formation), a numeric keypad 42 for specifying the number of prints, a clear/stop key 43 for canceling the number of prints or instructing to stop printing, and a number pad for displaying the number of prints, etc. Display unit 44, base color setting section 4 for setting the shade of the base color
5. Color intensity setting section 46 for setting color shading, color tone setting section 47 for setting color tone, and display 4 for performing various displays.
8. Original mode key 491 for selecting a mode depending on the image quality of the original and display section 49 for displaying the selected mode
2. Consists of a density designation key 71 for switching and setting the print density in five levels, and a display section 72 for displaying the set density. The display 348 includes a jam indicator 481 that lights up when a paper jam occurs in the 88 main body 1, and various states such as a ribbon cassette installed in the apparatus main body 1 with no ribbon or a cassette itself not installed. A ribbon display section 482, a paper display section 483 that displays the installed state of the paper feed cassette 13 or the presence or absence of paper, and a scanner display section 484, 48 that displays the operating state of the scanner section 21.
s, and a paper size display section 486 that displays the size of the paper in the attached paper feed cassette 13.

Further, the image forming section 5 has a configuration as shown in FIG. That is, the platen 50 is located approximately at the center of the image forming section 5, and the platen 5
0 (toward the left in the state of FIG. 5), a thermal head 51 as a recording head (thermal head) is attached to the platen 50.
It is arranged so that it can come into contact with and separate from it.

Further, the thermal head 51 has a ribbon cassette Rc.
The thermal head 51 and the platen 5
0, a thermal transfer ink ribbon (thermal transfer ribbon) 52 is interposed between the two. Then, the paper (image forming medium) P with this thermal transfer ink ribbon 52 interposed
is pressed against the platen 50, and in this state, a heating element (not shown) formed in the shape of a line tod of the thermal head 51 generates heat according to the image information, so that the ink on the thermal transfer ink ribbon 52 is heated and melted. It is designed to be transferred onto paper P.

In addition, a paper feed row 553 is provided in the apparatus main body 1 diagonally below the platen 50, and a paper feed cassette 13
The sheets P stored therein are taken out one by one one by one. The taken out paper P passes through the paper guide path 54 and is guided to a registration roller 55 disposed diagonally above the paper feed roller 53, and the registration roller 55 aligns its leading edge. After that, it is transferred toward the platen 50 and pressed against the platen 50 by rollers 56, 5.7.
It will be wrapped around and sent accurately.

Further, a manual feed detection switch 69 made of, for example, a photocoupler is provided in the guide section 11 to detect manually fed paper, and is operated in response to the detection of this manual feed switch 69 to detect paper fed manually. A roller pair 66 is provided for conveying the paper. The paper conveyed by this pair of rollers 66 is guided to the registration rollers 55 via a guide path 68 and a switch 67 consisting of, for example, a microswitch as a detection means.
As described above, it is wound around the platen 50 and is fed accurately.

The switch 67 is normally in an on state, and is turned off in response to the passage of paper. Further, the guide section 11 is provided with a manual feed guide (not shown) that is set according to the width of the paper during feeding. The mutual spacing between the manual feed guides is supplied to a main control section which will be described later.

On the other hand, the thermal head 51 is connected to the thermal transfer ink ribbon 5.
The paper P is pressed against the platen 50 through the sixth
As shown in the figure, the ink 6 on the thermal transfer ink ribbon 52
By heating and melting the ink 601, the ink 601 is transferred onto the paper P.

Further, the thermal transfer ink ribbon 52 has approximately the same size as the paper P, and has colors of yellow (Y) and magenta (M), as shown by range A in FIG. 7, for example.

Each cyan (C) ink portion 60a, 60b.

60G are installed side by side, or yellow (Y), magenta (M), cyan (C), black (
Each ink section 60a, 60b of BL).

60C and 60d are arranged side by side, and after transferring one color at a time, the paper P is returned to the transfer start position and accurately overlapped one after another.

In addition, each ink portion 60a to 6 of the thermal transfer ink ribbon 52
A bar code BG necessary for identifying each of the ink units 60a to 60d and controlling the leading edge of each ink unit Boa to 60d to match the leading edge of the paper P is provided in the side line portion corresponding to 0d. This barcode BG is read by a barcode detector (not shown).

Note that when the thermal transfer ink ribbon 52 is provided with a black ink portion 60d, this black ink portion 60d is used when it is desired to produce black clearly.

Three colors (60a~
60C) Almost black can be produced by overlapping.

In this way, the paper P is reciprocated by the number of colors by the rotation of the platen 50, but the path of the paper P at this time is the first one, which is sequentially arranged along the lower surface of the paper output tray 12. It will be guided onto the second guide 61.62.

That is, the transfer operation will be explained with reference to FIGS. 8(a) to 8(d). First, the paper ff1P supplied from the paper feed cassette 13 passes through the registration roller 55 and the first distribution gate 63, and is wound around the platen 50 (see FIG. 8(A)). .

Next, the platen 50 is rotated using a pulse motor (not shown) as a driving source to transport the paper P at a predetermined speed, and a heating element ( (not shown) generates heat according to the image information, and the ink 60 of the thermal transfer ink ribbon 52 is transferred to the paper P.

Further, the leading edge of the paper P that has passed through the platen 50 is sent onto a first guide 61 provided along the lower surface of the paper output tray 12 by a second distribution gate 64 (see FIG. )reference).

In this way, the paper P onto which the ink 60 of one color has been transferred is transported backwards by reversing the platen 50, and the lower surface of the first guide 61 is moved by the rotational displacement operation of the first distribution gate 63. (see FIG. 8(c)).

As described above, by reciprocating the MP a plurality of times, a plurality of colors are transferred.

Finally, the paper P to which all the colors of ink 60 have been transferred is
The paper is guided by the second sorting gate 64 to a pair of paper discharge rollers 65 and discharged onto the paper discharge tray 12 (see FIG. 8(d)).

Although not shown, in the case of manually fed paper, the same operation as described above is performed after the paper is conveyed to the registration roller 55 position by the roller pair 66.

FIG. 9 schematically shows the overall control system. That is, the main control section 100 as a control means is, for example, a CPLI (central processing unit).
It is mainly composed of a circuit and its peripheral circuits, and a pass line 101 is connected to this. This pass line 1
01 includes an operation panel 6 of the image forming section 5, a display control circuit 103 for controlling the operation panel 6, a storage section 104, a scanner control section 105, a photoelectric conversion section 106, a color conversion section 107.
The two-color separation section 108, the transport control section 109, the thermal head drive section 1101, the thermal head temperature control section 111, and the switch 67 are connected to each other. The display control circuit 103 connects the main control section 100 to the pass line 101.
The display 48 provided on the operation panel 6 displays 611111. Also,
Signals from keys operated on the operation panel 6 are supplied to the main control unit 100 via a pass line 101, and control is performed in response to these signals. Furthermore, the storage section 104 operates in response to a signal sent from the main control section 100 via the pass line 101, and stores information sent via the pass line 101 or reads out the stored information.

On the other hand, the scanner control section 105 operates in response to signals sent from the main control section 100 via the pass line 101, and controls the light source 23 and pulse motor 28 of the scanner section 21, and the photoelectric conversion section 106, respectively. The photoelectric conversion unit 106 detects an image on a document according to a signal sent from the main control unit 100 via the pass line 101, and outputs a digitalized light color signal. The color conversion unit 107 is the photoelectric conversion unit 1
The color signal of the light output from 06 is yellow, magenta,
It is converted into color signals of cyan and black inks, and these color signals are output to the pass line 101.

The two-color separation unit 108 converts the light color signal output from the photoelectric conversion unit 106 into, for example, black and red ink color signals, and is used to convert the light color signal output from the photoelectric conversion unit 106 into ink color signals, for example, black and red. Used when This two-color separation section 108
The output signal is output to the pass line 101. Furthermore, these two color separation section 108 and color conversion section 107 are connected to the pass line 1.
It is also possible to perform color conversion on the signal sent from 01 and output a sharp signal to the pass line 101.

The conveyance control unit 109 connects the main control unit 100 to the pass line 10.
a platen drive motor that operates in response to a signal sent through the platen 53 .1 and drives the platen 50 ;
A motor that drives the roller pair 66, the registration roller 55, the paper ejection roller pair 65, etc., and the first motor. Solenoids (none of which are shown) that drive the second imaging gates 63 and 64 are selectively driven. Thermal head drive section 110
operates in response to a signal sent from the main control section 100 via the pass line 101 and a signal from the thermal head temperature control section 111 to drive and control the heating element of the thermal head 51. The thermal head temperature control section 111 outputs a temperature control signal to the thermal head driving section 110 in response to a signal sent from the main control section 100 via the pass line 101.

Further, the paper conveyance position detection unit 112 determines the conveyance position of the paper P (from the time of feeding to the conveyance −
).

Thermal transfer ribbon drive circuit 113 includes main 1Ii 1160 part 1
The thermal transfer ink ribbon 52 is driven by controlling a ribbon drive motor (not shown) that drives the winding cores 87 and 88 of the ribbon cassette Rc in synchronization with the position signal of the paper P supplied from 00.

Further, the main till 18 section 100 includes a switch 67
The on/off state of the switch 67 is monitored, for example, every 5 ms, and when the off state of the switch 67 is detected, the time until the switch 67 is turned on is counted, or the paper conveyance position detection unit 112 detects the state of the paper. By counting the conveyance amount, the paper length is detected and
The size of the manually fed paper is detected from the width of the paper according to the settings of a manual feed guide (not shown).

Then, the main control section 100 determines the range for image formation according to the detected paper thickness, and based on this determination, the transport control section 109, the thermal head drive section 110, the thermal head temperature control section 111, It controls the thermal transfer ribbon drive circuit 113 and the storage unit 104, drives the paper P and the thermal transfer ink ribbon 52, and performs an image forming operation.

Next, in such a configuration, an image forming operation on manually fed paper will be described with reference to the flowchart shown in FIG. First, a document is set on a document table (not shown) of the image information reading device @2.

In this state, in step (ST) 1, the guide section 11
, and set the manual feed guide (not shown) to match the width of the paper. Then, in step 2, paper feeding is started along the manual feed guide set above. Then, as the paper is supplied, the roller pair 66 is driven in response to a signal supplied from the manual feed switch 69, and the paper is conveyed.

At this time, the paper transport position is determined by counting the number of pulses of the motor of the roller pair 66 (not shown) in the paper transport position detection unit 112.

Then, in step 3, the switch 67
When it is turned off, it is assumed that the leading edge of the paper has been detected, and a timer (not shown) starts counting in step 4. Further, in this state, the paper is fed blankly (conveyed without image formation), and in step 5 it is determined whether the switch 67 is turned on, and if the switch 67 is turned on, the trailing edge of the paper is detected. As a result, the counting of the above-mentioned timer is ended in step 6.

As a result, in step 7, the length of the paper is detected from the count value of the timer, the width of the paper is detected from the set position (width) of the manual feed guide, and from these values, the length of the paper is detected from the count value of the timer. The conveyance amount (number of feeding steps) of the sheet and the width (horizontal direction formation range) on which the image is formed are determined, corresponding to the image formation range. Then, in step 8, the paper that has been skipped is fed reversely according to the judgment of the paper conveyance position detection section 112, and the image information reading device 2 is driven with the leading edge of the paper corresponding to the transfer start position (A). Then, the entire surface of the document is exposed and scanned, and reading of image information is started.

Next, in step 9, it is determined from the range of the read image information whether or not the image information corresponds to the image forming range of the paper. As a result of this judgment, if the image information corresponds to the image forming range, the heating element of the thermal head 51 is driven in accordance with the signal from the thermal head temperature control section 111 in step 10, and the information for each scanning line is The image forming operation is performed by transferring the ink 60 of the thermal transfer ink ribbon 52 according to the image onto the paper using the thermal head 51.

On the other hand, if the result of the determination in step 9 is that the image information does not correspond within the image forming range, then in step 11 the image information is adjusted so that it corresponds within the image forming range. That is, in accordance with the image forming range, image information is controlled so that image information exceeding the number of feeding steps of the sheet being transported is not formed. Also, for information on the horizontal direction of the original image,
The image is controlled not to be formed in an area exceeding the width of the image forming area. As a result, in step 10, the heating element of the thermal head 51 is driven within the image forming range of the paper according to the signal from the thermal head temperature control section 111 using the image information adjusted in step 11, and 1 An image forming operation is performed by transferring ink 60 from the thermal transfer ink ribbon 52 onto the paper using the thermal head 51 in accordance with information for each scanning line.

Therefore, it is possible to always form an image according to the size of the supplied paper.

As described above, the image forming operation is performed according to the size of the supplied paper. Therefore, since it is possible to prevent image formation on a portion of the platen 50 that is out of the size of the paper, the platen 50 is not stained with the ink 60.

Note that in the above embodiment, in step 11,
The size of the detected paper and the size of the scanned original image were judged, and the original image to be formed was controlled based on these. If the image is forcibly formed in the image forming range, steps 9 and 11 can be omitted.

In addition, although paper was used as the image forming medium in the explanation,
For example, a transparent film used in an overhead projector (OHP) or the like may be used.

Further, although a thermal transfer type color copying machine has been described as an image forming apparatus, the present invention can be implemented similarly with a printer, facsimile, etc., for example. Furthermore, an electronic copying machine may be used as the image forming apparatus. In this case, since the image forming operation is performed according to the size of the paper, wastage of toner can be prevented.

Furthermore, if the conveyance amount (number of feeding steps) of the paper is made variable from the outside, it is also possible to arbitrarily form a margin at the leading or trailing edge of the paper.

[Effects of the Invention] As detailed above, according to the present invention, by forming an image according to the size of the image-forming medium, it is possible to prevent the platen from becoming dirty and to reduce wasteful consumption of toner. It is possible to provide an image forming apparatus that can be eliminated.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a flowchart for explaining the 8-bright image forming operation, FIG. 2 is a perspective view showing the external appearance of the image forming apparatus, and FIG. 4 is a perspective view showing a schematic configuration of an image information reading device;
5 is a side sectional view showing the structure of the image forming section, FIG. 6 is a perspective view for explaining the transfer operation state, and FIG. 7 is a diagram showing the thermal transfer ink ribbon. A plan view showing the state of ink application, FIGS. 8(a) to 8(d) are explanatory diagrams shown to explain the movement of paper during multicolor transfer, and FIG. 9 is a block diagram showing the configuration of the control system. . 2... Image information reading device, 5... Image forming section, 11
...Guide part, 66...Roller pair, 67...Switch, 68...Transport path 1.50...Platen, 51...
...Thermal head, P...Paper (image forming medium)
, 52... Thermal transfer ink ribbon, 60 (601)
... ink, 100 ... main control section, 109 ... conveyance control section, 112 ... paper conveyance position detection section, 113 ...
・Thermal transfer ribbon drive circuit. Applicant's representative Patent attorney Takehiko Suzue Figure 1 P Figure 6 A Figure 7] j Figure 8 Figure 8 wE9

Claims (5)

[Claims] (1) In an image forming apparatus having a forming means for forming an image on an image forming medium according to input image information, a detecting means for detecting the size of a manually fed image forming medium; An image forming apparatus comprising: a control means for controlling an image forming range of input image information according to a size of an image forming medium detected by a detection means. (2) The image forming apparatus according to claim 1, wherein the detecting means detects the size of the image forming medium along the conveyance direction. (3) The forming means has a thermal head and an ink ribbon, and image formation is performed by thermally transferring ink as a transfer agent by the thermal head. The image forming apparatus described in . (4) The image forming apparatus according to claim 1, wherein the forming means includes a developing device, and image formation is performed using toner from the developing device. (5) The image forming apparatus according to claim 1, wherein the control means is capable of arbitrarily setting an image forming range with respect to the size of the image forming medium.