JPH0722927Y2 - Image forming device - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention digitizes and processes image information of an original,
The present invention relates to an image forming apparatus such as a digital electronic copying apparatus that is taken out on a recording sheet.

[Conventional technology]

Of the recorded images obtained by digital electronic devices,
It is sometimes desirable to record an image on a transparent recording paper and see through this from the back.

For example, some OHPs project a reflected light image, but some OHPs project a transmitted light image by placing a document on a flat Fresnel lens, and in this case, a transparent paper document is used.
In such a case, it is desired that the OHP original can be freely written / erased on the back side with the printing side facing down.

In order for the image to become a normal image when the original is turned over,
It must be a mirror image during recording. Of course, the recorded image for normal use must be a normal image.

[Problems to be solved by the device]

As described above, it has been demanded that a normal image / mirror image of a recorded image can be freely obtained depending on the use / purpose of the recorded image or the type of recording paper.

[Purpose of device]

The purpose of this invention is to correspond to the purpose of use of the recorded image as described above, or a digital electronic device or the like that can freely select whether the recording is a normal image or a mirror image according to the type of recording paper. To obtain the image forming apparatus.

[Means for Solving the Problems]

The gist of the present invention for achieving the above object is to provide an image sensor unit for outputting image information of an original as an electric signal, a storage means for encoding the electric signal and storing it for each line, and In an image forming apparatus including a signal processing unit that reads out stored image signals serially line by line, and a recording unit that receives the read image signals and prints on recording paper, A sheet detection switch for detecting that a sheet has been fed, a mirror image address generation circuit for generating a mirror image address signal when a sheet is detected, and storing the mirror image signal in the storage means, and non-detection of a sheet. At that time, a normal image address generation circuit for generating a normal image address signal and storing the normal image in the storage means is provided.

[Action]

The apparatus is set in the operable state, and the recording paper is supplied to the recording unit according to the purpose.

In this case, when recording a mirror image, a sheet such as an OHP sheet is supplied.

The apparatus selects either normal or mirror image recording corresponding to the recording paper.

The image information of the original read by the image sensor unit and output as an electric signal is digitized in the signal processing unit and stored in the storage unit for each byte, and a normal image is obtained in accordance with the positive / mirror image signal. Alternatively, it is sent to the recording unit as a mirror image and recorded.

[Example of device]

 An embodiment of the present invention will be described below with reference to the drawings.

<Structure> First, the structure will be described.

As shown in FIG. 1, the digital electronic copying apparatus 10 includes an image sensor unit 100 for reading a document and converting it into an electric signal inside a box 11, and a character / image signal from the image sensor unit 100. A signal processing unit 200 that receives and processes the received image and a recording unit 500 that records the output image signal of the signal processing unit 200 on a thermosensitive recording paper are housed.

The box body 11 receives the AC power from the commercial power supply and houses the power supply unit 12 which constitutes a stabilized DC power supply of a plurality of levels.

On the other hand, on the upper surface of the box body 11, there is provided a document table 14 on which a document is placed and which is fed in the sub-scanning direction by a document table motor 13 provided in the box body. The platen 14 includes a transparent plate 15 such as glass and a pressure plate 16 covering the upper surface thereof, and is driven by a platen motor 13 and a pulley 18 driven via a belt 17, and a rack-pinion mechanism 19. It

The image sensor unit 100 includes an LED array 110 as an irradiation light source and a lens array 1 that collects reflected light from a document.
20 and a photoelectric conversion unit 130 including a large number of photoelectric conversion elements 135.

The lens array 120 is composed of a large number of fiber lenses (rod lenses) arranged in a line.

The photoelectric conversion unit 130 constitutes the number of pixels. For example, if it is configured to have 8 pixels / millimeter, 1728 photoelectric conversion elements 135 for A4 size are arranged in the main scanning direction.

As the photoelectric conversion element 135, CdS or the like as a photoconductive effect type sensor that changes the conductivity of the element by light irradiation is used, but a photovoltaic effect type sensor such as a photodiode may be used.

The photoelectric conversion unit 130 is provided near one end of the lens array 120, and is a so-called contact type image sensor unit.
It is 100.

As shown in FIG. 4, the signal processing unit 200 includes a level adjusting unit 250 that adjusts the variation of each photoelectric conversion element 135 in the image sensor unit 100, the detected image information of the document and the non-image information (ground color). Envelope detection unit 260 for adjusting the contrast with the threshold level generation unit 270 that outputs the threshold level from the dither data and the density selection signal selected externally, and the sample hold unit 215. From the threshold level generation unit 270, and has a comparison unit 220 that encodes image information, these encoded image signals are equal magnification. Alternatively, a line memory 340 is provided for receiving via a magnification selection unit 320 and a serial / parallel conversion unit 330 for recording at an enlarged or reduced magnification. It has been.

Between the line memory 340 and the output to the recording unit 500, a parallel / serial conversion unit 370 that outputs the image signal in series,
A central print control unit 380 for centering the recorded image on the thermal paper when reduced recording is selected, an all-black preheat data generation unit 390 for providing all-black information for preheating, and the like are provided.

In addition, C, which is the center of each functional unit of these signal processing units 200,
While the PU is arranged, a clock signal is issued to the sampling timing generation unit 300, the strobe width monitoring unit 420, the read timing generation unit 360, etc. from the original oscillation unit 205 that generates the reference clock for all the operations of the device 10. There is.

Further, a strobe generating section 410 is provided for controlling the energization time to each heating resistor in the recording section 500.

The line memory 340 is further supplied with a signal from the normal / mirror image address generation unit 350, which indicates whether the recorded image is a normal image or a mirror image.

The main ones of the above-described respective component parts in the signal processing unit 200 will be described in more detail below.

As shown in the block diagram of FIG. 5, the data sampling timing generation unit 300 and the threshold generation unit 270 for obtaining the enlarged recorded image include a plurality of frequency dividers 301 and 302 for dividing the original oscillation clock and these frequency dividers 301 and 302. A counter 303 that switches the frequency dividers 301 and 302 and the like, a changeover switch unit 304, and the like.

On the other hand, the threshold level generation unit 270 receives the dither matrix from the dither data register 280.
It has a D / A converter 271 for converting the digital amount of dither data output from the device into one analog voltage level and outputting the analog voltage level.

The positive / mirror image address generation unit 350 includes a 1/8 frequency divider circuit 355 for the basic clock as shown in FIG.
351 and bus switch 352, mirror image side counter 353,
In addition, the parallel / serial conversion unit 370, which is composed of the bus switch 354 and receives the output data from the line memory 340 that is a storage unit, is also the normal image side shift register 371.
And a mirror image side shift register 372.

The counters 351 and 353, the bus switches 352 and 354, and the parallel / serial conversion unit 370 are reading means.

Next, FIG. 7 shows a configuration on the reduction scale side in the scale selection unit 320.

In this example, as shown in the figure, the case of reducing to 2/3 is shown, and the reduction ratio selecting unit 321 thins out the basic sampling clock generated from the basic sampling clock generating unit 210 to 2/3. The reduced clock generation unit 322 and a counter 323 that counts the basic sampling clock and outputs all bits of one line, for example, 2/3 of 1728, that is, 1152 bits, are output. A high-speed basic sampling clock is output from the output from the first AND gate 324, which outputs the reduced clock of the reduced clock generator 322, and the H signal of the counter 323, during the active H period via the inverter 326. The second AND gate 325 that
And the OR of the second AND gates 324 and 325, OR
It comprises a gate 327, a counter 328 for detecting count-up of all bits, a third AND gate 329, and the like.

FIG. 8 shows the configuration of the central print control unit 380 that shifts the recording to the center of the paper when the reduction ratio (2/3) as described above is selected. Note that FIG. 8 shows only the normal image side.

Also, since it is a reduction of 2/3, a total of 216 bytes (1728/8) of 2 /
The figure shows a case where the recording of 3, that is, 144 bytes, is controlled so as to be positioned closer to the center. So 216
72 bytes out of the bytes are blank, and a half of 72 bytes of the blank portion, that is, 32 bytes, is blank in the main scanning direction from the paper edge.

Therefore, the central print control unit 380, the counter 381 that counts and outputs the 36 bytes, the first AND that outputs the logical product of the output signal of the counter 381 and the basic clock signal.
A gate 382, a NAND gate (AND gate + inverter) 383 that outputs the remaining 180 bytes excluding 36 bytes and outputs active L, and a basic clock during the input period of 180 bytes of this NAND gate 383 Second AND that outputs and sends the clock to output data from shift register 371
Made up of gates 384.

A latch 385 for holding the 37th byte and subsequent signals is provided on the output side of the counter 381.

As shown in FIG. 9, the strobe generating section 410 is the CPU 400.
A counter A411 that counts and outputs N ₁ pulses (4 pulses in this embodiment) of the counter pulse f from the counter A1 and a counter B412 that counts and outputs the N ₂ count (4 counts) of the counter A411. And these total counts N ₁ ×
The demultiplexer 413 transmits N ₂ (4 × 4 = 16 counts) as N (4) strobe signals STB1 to STB4 and switches the demultiplexer 413.

The strobe signals STB1 ... Change the strobe width according to the width of the original pulse f, and the change of the original pulse f is configured by the software of the CPU 400.

Next, in connection with the strobe generating section 410, the strobe width monitoring section 420 for monitoring the strobe counts F6 at the same time as the strobe is generated from the demultiplexer 413 as shown in FIG. At this time, a counter C421 that transmits a signal, a latch 422 that holds this output signal and transmits it to the demultiplexer 413, and inhibits the strobe signal, a latch B423 that latches the N ₁ count of the counter A411, and a latch B423 of this latch B423. An OR gate that clears the counter C421 by either the output (X) or the output signal (Y) of the demultiplexer 413.
Made of 424 and.

In this figure, a latch A414 for latching the strobe start signal and an AND gate A415 for passing the pulse signal of CO0 by the latched signal are added to the strobe generator 410 not shown in FIG. There is.

Next, the recording unit 500 will be described.

The recording unit 500 applies heat energy to heat-sensitive paper in response to an image signal, mainly a Sahemal head 550 that obtains a recorded image, a platen roller 501 that pushes the heat-sensitive paper against the Sahemal head 550, and the fed sheet. It is composed of a feed roller 502 for feeding a sheet.

A paper feed switch 503 for sending a paper feed signal is provided in front of the feed roller 502, and a discharge side of the platen roller 501 is provided with
A paper discharge switch 504 is provided.

In this case, in this embodiment, the paper feed switch 503 is used as a detection switch for automatically selecting the mirror image mode recording.

Inside the box body 11, there is provided a roll paper shaft 505 for roll-shaped thermal paper.

The platen roller 501 is configured to be driven in the sub scanning direction by a platen motor (stepping motor) 506 via a belt 507.

As shown in FIG. 11, the thermal head 550 is formed by arranging a large number of heating resistors 551 that form the number of pixels in the main scanning direction on one surface of a radiator 552 such as aluminum, and the surface thereof is a glass insulator. Covered with 553.

The heating resistor 551 has, for example, 8 pixels / millimeter, and 1728 A4 size elements are arranged. Further, dummy heating resistors for compensating the imbalance of the heat generation amount are provided at both ends, respectively. Are added one by one.

The heat generating resistor 551 in the thermal head 550 is grouped into a plurality of blocks as a whole, and FIG. 12 shows a block diagram of that block.

Each heating resistor 551 has one end connected to the recording power supply line 555 and the other end connected to a control switch group 556 that opens and closes in accordance with an image signal from the line memory 340 of the signal processing unit 200.
Then, a strobe signal gate 557 is provided for each block.
have.

The thermal head 550 is provided with a temperature detecting thermistor (not shown) for detecting the heat generation temperature.

<Operation> In the above configuration, this device operates as follows.

(Preparation for copying) Place the original on the original table 14 and turn on the power switch of the power supply 12.
Turn on. In this state, the line memory 340 generates an all-black preheat generation signal, and the thermal head 550 is preheated to a predetermined temperature.

The supplied thermal paper for recording includes a sheet fed from the front side of the feed roller 502 and a roll paper pre-loaded on a roll paper shaft 505 provided at the rear part of the platen roller 501. There is.

The thermal paper is formed by coating a color-developing layer on one surface of the base paper, and as the color-developing layer, for example, a leuco dye and a phenol compound, which are dispersed in a binder, are used. The binder melts and the leuco dye and the phenol compound come into contact with each other to develop color.

Normal paper is used as the base paper of the roll paper, but transparent resin is used as the base paper of the sheet, and a header of normal paper to which the coloring layer is not applied is attached to the leading end.

In FIG. 1, the sheet is inserted between the platen roller 501 and the feed roller 502 through the paper feed switch 503, and when the sheet feed switch 503 receives the signal, the platen motor 506 is driven.
Starts and the thermal paper is fed. At this time, in the signal processing unit 200, by the action of the positive / mirror image address generation unit 350,
The mirror image address generation side is selected. Then, the obtained recorded image is seen as a normal image when viewed from the back surface of the base paper of the thermal paper, that is, the side not coated with the color forming layer.

The sheet sent along the platen roller 501 passes between the sheet and the thermal head 550, and when the header portion of the sheet edge is detected by the sheet discharge switch 503, the platen motor 506.
Moves the header portion immediately below the thermal head 550, performs forward / backward movement several times at this position, and then returns to the position of the paper feed switch 503 to complete the preparation.

In the forward / backward movement, the print residue attached to the surface of the insulator 553 covering the surface of the heating resistor 551 of the thermal head 550 is rubbed off by the header portion of the thermal paper.

In the case of roll thermal paper, since the paper feed switch 503 does not operate, when the paper edge reaches the paper discharge switch, the preparation is completed as it is, and the normal / mirror image address generation unit 350
The normal image side is selected at.

(Recording Operation) At the same time as the above-mentioned preparation operation is completed, the apparatus 10 starts the recording operation.

In the recording operation, the document table 14 is sent in the sub-scanning direction, the image sensor unit 100 scans the document in the main-scanning direction and sends out image information, while the signal processing unit 200 processes these image information. And sends it to the recording unit 500.

In the recording section 500, the thermal paper is normally synchronized with the platen and the image signal is recorded while being sent in the sub-scanning direction.
Particularly in the case of recording reduced in the sub-scanning direction, that is, so-called fine mode recording, the image is fed at the sub-scanning feed speed corresponding to the reduction ratio.

The main operations of these recording operations will be described below.

(Sub-scan feed amount and strobe width control operation) When fine mode recording is selected in the recording operation, the thermal paper is fed with a small feed amount in the sub-scan direction. Such fine mode recording can be performed, for example, with an A4 size original 2 /
If you send it as 3, you can get a nearly square record and you can use it as it is as an OHP original on the OHP square original plate equipped with a Fresnel lens.

In fine mode recording, if the thermal head 550
When the normal energization is performed, the pixels in the front row and the pixels in the rear row overlap each other as shown in FIG. 13A, and the obtained entire image has a desired density or more.

Therefore, as shown in FIG. 9, in the fine mode recording, the counter pulse (f) is reduced by software,
By reducing each strobe signal width, STB1 to STB4, in proportion to the sub-scanning amount of the thermal paper, as shown in FIG. 13B, the overlap is eliminated and the recording density is made constant.

That is, by reducing the strobe width in proportion to the sub-scan feed amount, as in the present apparatus 10, FIG.
Compared with this, the recording pixels in FIG. 13B are smaller, and there is no overlap between the front and rear lines.

(Strobe width monitoring operation) As shown in FIG. 12, the strobe signal is given to each block of the heating resistor 551 of the thermal head 550, and the image signal is given by the signal from the line memory 340. The energization time of the pixel is controlled.

In the normal case, each strobe signal switches for each block and shifts to the strobe signal of the next stage, but if a certain strobe signal becomes larger than the predetermined time width, it will be automatically Strobe signal is prohibited, and thermal paper does not record.

That is, in FIG. 10, the counter pulse signal CO0
Is taken into the counter A411 by the signal of the latch A414 generated by the strobe start signal 0ST and 4
It is transmitted every count, and the counter B412 transmits this every four counts. Then, as shown in FIG. 10, the demultiplexer 413 causes the four strobe signals STB1 to STB1.
As TB4, it is sequentially transmitted, but the signal of F6 is counted by the counter C421, which is greater than any of STB1 to STB4, and when it reaches a predetermined count, it is output to the latch C422. An inhibit signal is issued to the demultiplexer 413 via the latch C422.

(Enlargement Recording Operation) In the magnification selection unit 320, for example, as shown in FIG. 5 showing the case where 3/2 times enlargement recording is selected, a double speed sampling timing signal is issued once every three times. That is, the same image signal is output once every three times, and the recording is expanded by this amount.

However, if the image information thus overlapped is encoded by comparing it with a constant threshold level as it is, the obtained recorded image becomes awkward with variations in shade.

Therefore, as shown in FIG. 5, the dither data stored in the dither data register 280 is transmitted from the predetermined dither data matrix at each sampling timing, and the D / A converter 271 outputs one threshold value. The level is sent to the comparison unit 220.
Such a threshold level is held,
It is possible to provide a random comparison value to the duplicated data, give variations in the coding of the duplicated data as a whole, and obtain a recorded image having a pseudo halftone.

(Enlargement recording operation) The operation of reducing the vertical scanning direction of the recorded image by reducing the sub-scan feed amount of the thermal paper has already been described.
At 320, in order to obtain reduced recording in the main scanning direction, unlike the reduction in the sub-scanning direction, it is obtained by thinning out data in the main scanning direction.

Therefore, the reduction recording operation for reducing to 2/3 will be described with reference to FIG. 7. The basic sampling clock is thinned out by 1/3 by the reduction clock generation unit 322 and sent to the first AND gate 324.

Since the output from the counter 323 is input to the first AND gate 324 via the inverter 326, the counter 323
However, it becomes H input until 2/3 of the total count 1728, that is, until 1152 counts, and the output from the reduced clock generation unit 322 is directly output from the first AND gate 324.

Then, at the 1153th count, the L signal is output from the inverter 326, and the input from the reduced clock generation unit 322 is cut. That is, after that, it becomes an all-white signal.

On the other hand, since the high-speed clock signal and the output signal of the counter 323 are input to the second AND gate 325, after the 1153th count, the high-speed clock is output from the second AND gate 325 and input to the OR gate 327. .

In other words, from OR gate 327, 2/3 up to 1152 count
The reduced clock thinned out is transmitted, and after the 1153th count, the high speed clock is transmitted and output through the third AND gate 329.

On the other hand, the output of the OR gate 327 is also input to the counter 328, and is inverted and output when the thinning signal and the high-speed signal are counted 1728 in total, so the third AND gate 32
9 is closed and the sampling clock for one line is completed.

In this way, the sampling of the blank area is performed at high speed, so that the entire recording operation is speeded up.

(Normal / Mirror Image Recording Operation) In this apparatus 10, the normal image is automatically selected on the roll thermal paper, and the mirror image recording is automatically selected on the sheet thermal paper by the paper feed switch 503. These operations will be described with reference to the drawings.

The encoded image signal is sent to the serial / parallel converter 33.
The byte address is transferred to the line memory 340 via 0 and the byte address is transferred to the line memory 340 via the normal image counter 351 or the mirror image counter 353. Then, in the case of a normal image by selecting either the normal image or the mirror image, the recording unit 500 from the line memory 340 through the shift register 371.
In the case of a mirror image, it is also transmitted via 372.

Since the image signal is transmitted for each byte, in the case of a mirror image, the order within each byte as well as each byte itself
The images are taken out in the reverse order to the case of the normal image.

(Central printing control operation) This is not a problem when only normal image recording is used, but with this device that can obtain a normal image and a mirror image, especially in the case of a mirror image, when viewing the actually recorded image, You have to look at the right image.

In the above case, especially when the reduced recording image is biased to one side of the paper surface, when viewed from the back side of the paper, the image position appears to move to the left and right, which causes a feeling of strangeness.
It is recorded near the center of the page.

The case of a normal image reduced to 2/3 will be explained based on FIG. 8. 216 × 1/3 = 72 bytes out of the total 216 bytes become blank, and by dividing this blank part into 36 bytes left and right, The recorded image will be located at the center.

Therefore, as shown in FIG.
It is closed by the L signal of the counter 381 which does not output up to 6 bytes, and is taken into the counter 351 from the 37th byte.

On the other hand, the clock signal of the shift register 371 for reading the signal from the line memory 340 is passed through the second AND gate 384, and the second AND gate 384 subtracts 36 bytes for the front blank from all 216 bytes. Since the input is made together with the NAND gate 383 which outputs only 180 bytes, the shift register (parallel / serial conversion unit) 371 will start transmitting data thereafter. There is no problem because the blank 36 bytes in the latter half is read as blank data.

[Effect of device]

According to the digital electronic copying apparatus of the present invention, a sheet detection switch for detecting the feeding of the sheet and a mirror image address signal when the sheet is detected are stored in the storage means. Since the mirror image address generation circuit for storing the mirror image signal and the normal image address generation circuit for generating the normal image address signal when the sheet is not detected and storing the normal image in the storage means are provided, a simple circuit is provided. It is possible to obtain an orthoimage and a mirror image in the configuration. In particular, a normal image or a mirror image is uniquely recorded depending on the type of recording paper (roll paper or sheet).
Therefore, when recording a mirror image on OHP paper, it is not necessary to perform the operation of selecting the mirror image mode, which is extremely convenient when creating an OHP document. , A positive / mirror image recording can be freely obtained from a simple circuit configuration.
It is convenient to get a mirror image manuscript.

[Brief description of drawings]

1 to 13 show one embodiment of the present invention,
Each figure represents the following: FIG. 1 is a side structural view of a digital electronic copying apparatus, FIG. 2 is a sectional view taken along line II-II in FIG. 1, FIG. 3 is a structural explanatory view of a document table, and FIG. A block diagram, FIG. 5 is a block diagram of a sampling timing generation circuit for an enlarged image and a threshold level generation unit, and FIG.
Mirror image writing / reading circuit diagram, FIG. 7 is a sampling clock generating circuit diagram at the time of reduction, FIG. 8 is a circuit diagram for central print control (in the case of a normal image), FIG. 9 is a strobe generating circuit diagram, FIG. 10 is a block diagram of the strobe width monitoring unit, FIG. 11 is a perspective view of the thermal head, FIG. 12 is a configuration diagram of the thermal head, and FIG. 13A is recording when reducing in the sub-scanning direction without strobe width control. FIG. 13B is an operation explanatory view showing pixel overlap, and FIG. 13B is an operation explanatory view showing recording pixels when strobe width control is performed corresponding to sub-scan feed.

Claims (1)

[Scope of utility model registration request] 1. An image sensor unit for outputting image information of a document as an electric signal, a storage means for encoding the electric signal and storing the encoded signal for each line, and the stored image signal serially for each line. An image forming apparatus including a signal processing unit configured to read out a reading unit and a recording unit configured to receive the read image signal and print the recording sheet on a recording sheet, the sheet detecting unit detects that the sheet is fed. A detection switch, a mirror image address generation circuit that generates a mirror image address signal when a sheet is detected, and stores the mirror image signal in the storage unit, and a normal image address signal when a sheet is not detected, An image forming apparatus comprising: a normal image address generation circuit for storing a normal image in a storage means.