JPS6376566A - Picture data reader - Google Patents

Abstract

PURPOSE:To obtain good read data which is not affected by shading, by using the reference value for shading correction which is preliminarily obtained based on read data of the white part of an original. CONSTITUTION:Picture data of the white part on the original surface is read by a sensor 15 which receives the reflection of the light projected to the original surface to read picture data on the original, and this data is stored in a storage means 60 correspondingly to the read position, and the reference value for shading correction is operated in this state in each read position in accordance with stored data of the storage means 60, and this reference value and picture data on the original surface read by the sensor 15 are compared with each other to obtain binarized picture data. Thus, good read data which is not affected by shading is obtained and picture data is stably read.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an image data reading device having a shading correction means.

[Prior art and its problems] Recently, ultra-compact hand-held copy machines and the like have been equipped with a system that irradiates light from a light source onto the document surface, receives reflected light from the document surface with an image sensor (CCD), etc., and generates image data. An image data reading device is used to read the image data.

By the way, when such a device reads a white part of a document, the reading level at this time deteriorates significantly at the periphery of the effective reading range as shown in Figure 7, and the so-called black level is detected. Shading may occur and good read data may not be obtained. Possible causes of such shading include non-uniformity of the light illuminance irradiated onto the document surface, a decrease in the amount of light around the reading area due to the imaging characteristics of the lens system, and variations in the output of each pixel of the CCD.

Conventionally, as a means to correct such shading, (1) a metallic slit-shaped mask (
shading correction plate), (2
) A method is being considered in which an anti-transparent film smaller than the lens is attached to the lens surface on the sensor side.

However, in the case of (1), the amount of light irradiated onto the document surface is insufficient, making it difficult to read data stably.
Further, in the case of (2), since the lens solution +S tt decreases, it is difficult to read data stably, and in addition, it also has the disadvantage of being expensive.

[Purpose of the Invention] This invention was made in view of the above circumstances, and it is possible to obtain effective shading correction, obtain good read data without the influence of shading, and stably read image data. An object of the present invention is to provide an image data reading device that can perform the following operations.

[Summary of the Invention] An image data reading device according to the present invention uses a sensor that reads image data on a document by receiving reflection of light irradiated on the document surface, and reads image data for a white portion of the document surface. The data is stored in the storage means in correspondence with the reading position, and in this state, a reference value for shading correction is calculated for each of the above reading positions from the data stored in the storage means, and this base W value and the sensor The configuration is such that binarized image data is obtained by comparing the image data of the document surface that is output one after another.

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

In this case, the embodiment shows an example in which the present invention is applied to a one-day copy machine. . FIG. 1 shows the external configuration of a handy copy machine embodying the present invention. In the figure, 1 is the main body of a handy copy machine, for example, 70 mm wide and 30+ nm thick.

It has a height of approximately 160 mm, an effective reading width, an effective printing width of 40 mm, and a reading memory length of 200 mm.

It is assumed that the read dot density is 8 dots/mm and the print dot density is 8 dots/mm. The handy copy machine main body 1 is provided with a head portion HA for reading and printing at its tip, that is, its lower end in the figure. The head portion HA is smaller in width and thickness than the handy copy machine main body 1, and a stepped portion is formed between the head portion HA and the handy copy machine main body 1. The tip surface of the upper seam head portion HA is formed obliquely from the center toward both sides, and the slope portion 1as1
A reading section 2 and a printing section 3 are respectively provided at b.

In addition, the above-mentioned handy copy machine main body (2) is provided with a power/read/print selector switch 4 at the bottom of the - side (as shown in the figure), and operation keys 5a and 5b are provided on both the front and back sides of the body so that the levers 1 are opposed to each other. provided. This operation key 5a,
5b is formed in the shape of a flat plate, and the handy copy machine main body 1 can be moved back and forth by holding the upper surface thereof by hand. Above power/read/print selector switch 4
is used to specify the on/off, reading, and printing operation modes of the power source 1, and the power is turned on when each mode of reading and printing is specified. Further, the handy copy machine main body 1 has a clear key 6, a density adjustment volume 7 for adjusting print density, and a test mode/normal mode at the end opposite to the side where the reading section 2 and printing section 3 are provided. A changeover switch 71 is also provided. The clear key 6 is used to erase the image memory when reading an image, and is used to locate the beginning of image data when printing. Find the reference value, that is, the threshold value. The handy copy machine main body 1 also has a power source LE close to the reading section 3.
D8 is provided, and a memory LED 9 and a speed warning LED 10 are also arranged on the upper end side in the figure of the front part.

When reading a document using the handy copy machine, the power/read/print switch 4 is set to the "read" position. Power/read/print switch 4
When set to the “read” position, the power is turned on and the power is turned on.
ED8 lights up. In this state, the reading section 2 is brought into contact with the document surface and moved while pressing the operation keys 5a and 5b. If the moving speed of the handy copy machine main body 1 is too fast, a speed warning LED 10 is issued.

When printing out the scanned image data, after switching the power/reading/printing switch 4 to the "Print" position, bring the printing section 3 into contact with printing paper A (plain paper), and then press This is done by moving the handy copy machine main body 1 in the direction of arrow X while pressing keys 5a and 5b.

Next, details of the reading section 2 and printing section 3 provided in the handy copy machine main body 1 are shown in Figures 2 and 3.
This will be explained using figures. As shown in FIGS. 2(a) and 2(b), the reading unit 2 includes a light source 11 consisting of an LED array disposed in the handy copy machine main body 1 in close proximity to the slope portion 1a. The reading source TAB is illuminated through a reading window 12 provided in 1a. In addition, there is a slope section 1 inside the copy machine body 1.
A light guide 13 is provided that extends upward from near point a, and a lens 14 and a -dimensional image sensor 15 are sequentially arranged at a predetermined interval on the upper end side of this light guide 13.

The -dimensional image sensor 15 is, for example, a 1024-bit one-dimensional CCD, of which 320 bits (8 do
t/mm and 40mm width) is used. The lens 14 and the -dimensional image sensor 15 are mounted on a support 16
is held in place by the

This support body 16 is fixed to an inner frame 17 provided inside the handy copy machine main body 1 at a predetermined interval. An electronic component mounting section 18 and a battery storage section 19 are provided adjacent to the support body 16;
The above-mentioned -dimensional image sensor 15 is connected to a circuit board 20 mounted on the circuit board 8 . Further, the clear key 6, the density adjustment volume 7, etc. are connected to the circuit board 20.

In the inner frame 17, there are provided an ink ribbon roll 22 for the thermal head 2L, a constant speed feed roller 23, and an ink ribbon take-up roll 24. 26.2
7.28.29.30 will be provided. Above rubber roller 2
5a and 25b are rotatably mounted on the inner frame 17 via a shaft 31, and their outer peripheral surfaces slightly protrude outside from cutouts 32 provided on both sides of the sloped portions 1a and lb. The gear 26 is coaxially fixed to one side of the rubber roller 25a. Second gear 26
is formed to have a smaller diameter than the rubber roller 25a, and the intermediate gear 2
It is connected to the gear 28 via 7. This gear 28 is
The t9 speed feed roller 23 via the one-way clutch 33
is connected to the shaft of

This one-way clutch 33 is configured to transmit the rotation of the primary side to the secondary side only during printing operation, that is, the rotation of the gear 28 to the constant velocity feed roller 23 side.

Further, an encoder disk 34 is attached to the primary side of the one-way clutch 33, and the gear 28 and the encoder disk 34 are connected to each other regardless of the clutch operation of the one-way clutch 33.
4 and 4 rotate together.

As shown in FIG. 3, the encoder disk 34 is provided with a number of slits 35 radially spaced at regular intervals. Then, the LED 3B and the photo sensor 37 are arranged so as to face each other t11 with the encoder disk 34 interposed therebetween. In this case, LED3B is shown in Figure 2 (
As shown in a), the photo sensor 37 is installed inside the handy copy machine main body 1, and the photosensor 37 is installed inside the inner frame 17. A through hole 38 is provided in a portion of the inner frame 17 where the photosensor 37 is W
8 and enters the photo sensor 37. That is, the encoder disk 34, L E D
3fli, a photosensor 37, and the like constitute an encoder 39.

Further, on the sloped portion 1b of the print section 3, a print window 41 and an ink ribbon guide window 42 are provided in parallel, as shown in FIG. In this case, the ink ribbon guide window 42 is located inside the print window 41. The heat generating part 21a of the thermal head 21 is inserted into the print window 41, and positioned so that its tip side protrudes slightly from the slope part 1b. As shown in FIG. 2(b), a slit 43 is provided in the stepped portion of the handy copy machine main body 1 on the side where the operation key 5a is provided.
The thermal transfer ink ribbon 22a pulled out from the slit 43 is led out to the outside of the handy copy machine main body l,
Thereafter, the ink ribbon passes through the heat generating portion 21a of the thermal head 21 and is introduced into the interior of the handy copy machine main body 1 through the ink ribbon guide window 42. The ink ribbon 22a introduced into the main body of the handy copying machine is guided by a shaft 31, an ink ribbon guide 44, and a continuous feed roller 23, and is wound onto an ink ribbon take-up roll 24. Furthermore, the above-mentioned handy copy machine main body 1 is
As shown in FIG. 2(b), the surface on which the operation key 5b is provided is formed so that it can be opened and closed by a hinge 45,
The ink ribbon 22a can be replaced, the interior can be inspected, etc.

Next, the configuration of the electronic circuit formed on the circuit board 20 will be explained with reference to FIG. 4. As described above, the encoder 39 is composed of the encoder disk 34, the LED 3B, the photo sensor 37, etc., and outputs a pulse signal corresponding to the amount of movement of the handy copy machine main body 1, that is, a movement amount detection signal.

The movement amount detection signal output from this encoder 39 is
Control section 51, timing signal generation section 52, speed detection section 5
Sent to 3. The control unit 51 includes the power supply/read/
Keys and switch group 5, including print selection switch 4, operation keys 5a, 5b, clear key 6, density, 7S adjustment volume 7, test mode/normal mode changeover switch 71, etc.
An operation signal is given from 4, and the thermal head 2
A temperature detection signal is provided from a temperature sensor 55 that detects the temperature of the printing paper 1 and the temperature of the printing paper. Then, the control unit 51
L according to the operation signal from the L key and switch group 54
In addition to controlling the lighting of the power LED 8 and memory LED 9 in the ED section 50 and controlling other parts, it also issues operation commands to the timing signal generating section 52 according to the reading mode or print mode specified by the power/reading/printing switch 4. Give Sl and S2. in this case,
The control unit 51 gives the timing signal generating unit 52 an operation command S1 if the mode is a read mode, and an operation command 82 if the mode is the print mode.

Furthermore, the control unit 51 transmits the test mode command to the selector 65.
At the same time, a write/read command is given to the white health data storage section 66.

When the timing signal generating section 52 receives an operation command S1 from the control section 5I, it generates a CCD exposure timing signal a1 of a constant period and a data transfer lock signal f, and also generates a movement amount detection signal from the encoder 39. Various timing signals such as serial/parallel conversion signal b1 and clock pulse C are generated in synchronization with each other. Further, the timing signal generation section 52 generates a print timing signal when the operation command S2 is given from the control section 5I. Then, the CC output from the timing signal generation section 52 is
The D exposure timing signal a is sent to the one-dimensional image sensor 15, and the data transfer lock signal d is sent to the one-dimensional image sensor 1.
The serial/parallel conversion signal is sent to the serial/parallel converter 58 and the address counter 69, and the clock pulse C is sent to the address counter B1. The -dimensional image sensor 15 reads the reflected light from the original B in synchronization with the COD exposure timing signal, and outputs it to the selector 65 via the amplifier 56. The second selector 65 supplies the output of the amplifier 56 to the A/D converter 67 and the other outputs to the comparator 68 according to the test mode command from the control unit 51 . The A/D converter 67 converts the output for each pixel of the above-mentioned -dimensional image sensor 15, that is, the output for each reading position, into two short signals and supplies them to the white level data storage section 66. In this case, the write address (row and column address) to the white level data storage section 6G is designated by the address counter 69. The white health data storage section 66 reads data according to the cleaning command from the control section 51 and outputs it to the calculation section 7.
Give to 0. In this case, the read address (row and column address) to the white level data storage section 6B is specified by the address counter θ9. The calculation unit 70 includes a control unit 51
Concentration setting data that serves as a more standard is provided. Then, a reference value for shading correction is determined by the calculation unit 70, and this reference value is provided to the D/A conversion unit 57 as a threshold value. The D/A converter 57 converts the input signal into an analog signal and supplies it to the comparator B8. This comparator 68 compares the threshold value calculated by the calculation section 70 with the output from the one-dimensional image sensor 15 provided via the amplifier 56, and outputs this comparison output to the real/parallel conversion section 58. This serial/parallel converter 58
converts the input signal into a parallel signal every 8 bits using a serial/parallel conversion signal, and outputs it to the image data memory 60 via the data selector 59. Further, the data selector 59 has a data line connected to the control section 51, and either the serial/parallel conversion section 58 or the control section 51 is selected by the select signal d from the control section 51. The write address (row and digit address) of the image data memory GO is determined by the address counter 6.
1 and designated via the address selector 62. Further, the read address of the image data memory 60 is given by the control section 51 via the address selector 62. This address selector 62 selects the address counter 61 side in the reading mode and selects the single tone part 51 in the print mode to designate the address of the image data memory 60 according to the select signal e from the control unit 51. .

Therefore, when the reading of the document in item 1 is completed and the mode is switched to the print mode, the control section 51 outputs the operation command S2 to the timing signal generation section 52 as described above, and also changes the amount of movement from the encoder 39. The data stored in the image data memory 60 is sequentially read out via the data selector 59 in accordance with the detection signal. When the control unit 51 reads image data from the image data memory 60, it outputs the image data to the thermal head drive circuit 64, and also outputs the number of black characters in the print data, the temperature detection signal from the temperature sensor 55, and the density adjustment volume. The power supply time is set based on the value of 7, and the operation time of the power supply and power supply control unit 65 is controlled. When the thermal head drive circuit 64 receives print data from the control section 51, the timing signal generation section 52
The thermal head 21 is driven in synchronization with a timing signal from.

Next, the operation of the above embodiment will be explained.

First, before reading a document, a reference value for shading correction, that is, a threshold value is determined.

This includes test mode/normal mode switching switch 7.
1 to test mode. At the same time, the power/read/print selector switch 4 is switched from the "power off" position to the "read" position.When the power/read/print selector switch 4 is switched to the "read" position, the power is turned off. The control unit 51 lights up the power LED 8 in the LED unit 50 to indicate that the power is turned on, and sends the operation command S1 to the timing signal generation unit 52. The control section 51 also provides a test mode command to the selector 65 and a write command to the white level data storage section 66 .

In this state, the user brings the reading section 2 formed in the head section HA shown in FIG. 2(b) into contact with the white surface of the document B. At this time, the projected light from the light source 11 is irradiated onto the document B through the reading window 12 provided on the sloped portion 1a, and the reflected light is incident on the one-dimensional image sensor 15 via the light guide 13 and lens 14. In this state, the timing signal generator 52 receives the operation command S1 from the controller 51.
When given, a CCD exposure timing signal a of a constant period is generated and given to the -dimensional image sensor 15, and a data transfer lock signal f is given to the address counter 69. The -dimensional image sensor 15 outputs a signal corresponding to the light reflected from the white surface of the document B in synchronization with the CCD exposure timing signal a from the timing signal generator 52. The output signal of each pixel corresponding to the reading position of the -dimensional image sensor 15 is amplified by the amplifier 56 and sent to the A/D converter 67 via the selector 65. This A/D converter 67 converts the image signal sent via the amplifier 56 into a two-short signal and supplies it to the white level data storage 6G.

In this case, the address of the own level data storage section 66 is specified by the address counter 69. The address counter 69 sequentially increments the digit addresses by "+1" in response to the data transfer lock signal f, and specifies the address of the white level data storage section 66. In this way, the data for the white portion of the document is written into the white level data storage section 66.

After that, the test mode/normal mode switching switch 71
is switched to normal mode, and information such as text and images on the normal document surface can be read. In this case, the control unit 51 controls the L
The power supply LED 8 in the ED section 50 is kept lit, and an operation command S1 is given to the timing signal generation section 52. The control unit 51 also controls the white level data storage unit 66.
Give read command to.

In this state, as shown in FIG. 2(b), the user moves the reading section 2 formed in the head section HA to the document B.
, and move the handy copy machine body 1 forward toward the operation key 58 side while pressing the operation keys 5a and 5b.

At this time, the projected light from the light source port is irradiated onto the surface of the document 8 through the reading window 12 provided on the slope portion 1a, and the reflected light is incident on the one-dimensional image sensor 15 via the light guide 13 and lens 14.

Further, as the handy copy machine main body 1 moves, the rubber rollers 25a and 25b rotate in contact with the surface of the document 8, and the rotation is transmitted to the gear 28 via the gears 26 and 27. As the gear 28 rotates, the encoder disk 34
rotates at a speed proportional to the moving speed of the handy copy machine main body 1. Due to this rotation of the encoder disk 34,
Photo sensor 37 from LED 36 through slit 35
The light sent to the photo sensor 37 is controlled intermittently, and a pulse signal is output from the photosensor 37.

The pulse signal outputted from this photosensor 37 becomes the output of the encoder 39 in FIG.
sent to.

On the other hand, when the timing signal generation section 52 receives the operation command S1 from the control section 51, it generates a CCD exposure timing signal a of a constant period and supplies it to the -dimensional image sensor 15, and also sends a data transfer lock signal f to the address address. A serial/parallel conversion signal is generated according to the movement amount detection signal from the encoder 39 and output to the serial/parallel conversion section 58 . Further, the timing signal generating section 52 generates a clock pulse C in synchronization with the serial/parallel conversion signal S, and outputs it to the address counter 61.

Thus, the -dimensional image sensor 15 outputs a signal corresponding to the light reflected from the surface of the original 8, that is, an image signal, from the timing signal generating section 52 in synchronization with the CCD exposure timing signal. The output signal of this -dimensional image sensor 15 is amplified by an amplifier 56 and sent to a selector 65.
and is then sent to comparator G8. On the other hand, data is read out from the white level data storage section 66 in synchronization with the output from the -dimensional image sensor 15. In this case, the read address of the white level data storage section 6G is specified by the address counter 69. The address counter 69 sequentially increments the digit address by T+1 in response to the data transfer lock signal f, and specifies the address of the white level data storage section 66. In this way, the data of the white portion of the document stored in the white level data storage section 66 is read out. This data is then sent to the l calculation section 70. The calculation unit 70 is given reference density setting data from the control unit 51, and a reference value for shading correction is calculated based on this setting data. The calculated reference value is then converted into an analog signal via the D/A converter 57 and sent to the comparator 68 as a threshold value.

This comparator 68 outputs a comparison output to the serial/parallel conversion signal 58. The serial/parallel converter 58 converts the serial input signal into parallel image data every 8 bits, for example, in synchronization with the serial/parallel conversion signal sent from the timing signal generator 52, and sends it to the data selector 59. Output. This data selector 59 is switched to the serial/parallel converter 58 side by select d from the controller 51 when the reading mode is designated. Therefore, the data output from the serial/parallel converter 58 is sent to the image data memory 8o via the data selector 59. The address of this image data memory 60 is specified via the address selector 62, but at this time the address selector 62 is switched to the address counter 6I side by the select signal e from the control section 51. Therefore, the address of the image data memory 60 is specified by the count output of the address counter 61.

The address counter 6X includes a timing signal generator 5
The clock pulse C from 2 sequentially addresses the digits or “+
1'' and specifies the address of the image data memory 60. When one line of image data is written into the image data memory 60, the timing signal generator 52 stops generating the timing signal and waits until the next movement detection signal is sent from the encoder 39. state. Thereafter, similar operations are repeated, and the image data read from document B is compared with the threshold value and sequentially written into image data memory 60 in a shading-corrected state. In this case, as shown in FIG.
), and if the reference value for shading correction, that is, the threshold value, obtained from the read data of this white part is set to (b) in the same figure, then the image data obtained by actually reading the original ((C) of the same figure) )), the comparator 68 obtains binary data of white and black as shown in FIG.

Next, the operation when printing out the image data read from document B as described above will be explained. When printing/outputting image data, turn off the power/read/
Switch the print changeover switch 4 to the print position. By switching the power/read/print selector switch 4, the print mode is entered, and the control unit 51 outputs the select signal d,
e, the data selector 59 and address selector 62
1 [Switch to the phloem 51 side. Knee in this state.
As shown in FIG. 1, the print section 3 in the head section HA is brought into contact with the printing paper A, and the handy copy machine main body 1 is moved in the direction of the arrow X shown in the figure without pressing the operation keys 5a, 5b. As the handy copy machine main body l moves, the rubber rollers 25a and 25b rotate, and the rotation causes the gears 26.
7 to the pawl 28.

As the gear 28 rotates, the encoder disk 34 rotates, and a movement amount detection signal is taken out from the photosensor 37 in accordance with the movement speed of the handy copy machine main body 1, as in the above reading.

Further, the rotation of the gear 28 is transmitted to the constant speed feed roller 23 via the one-way clutch 33, and further the rotation of the gear 29.
0 to the take-up roll 24. As a result, the constant speed feed roller 23 and the take-up roll 24 rotate, and the ink ribbon roll 22 passes through the stepped slit 43, the heat generating part 21a1 of the thermal head 21, the ink ribbon guide window 42, and the shaft 3L ink ribbon guide 44. The ink ribbon 22a guided by the constant speed feed roller 23 is wound up. In this case, the continuous feed roller 23 is arranged so that the movement of the handy copier main body 1 is adjusted so as not to generate a relative speed between the printing paper A and the ink ribbon 22a. and rotate.

On the other hand, the movement amount detection signal output from the photosensor 37 is sent to the control section 51, the timing signal generation section 52, and the speed detection section 53 as an output signal of the encoder 39, as described above. The timing signal generating section 52 includes:
In response to the movement amount detection signal sent from the encoder 39, a one-line print command is output to the control section 51, and a print timing signal is output to the thermal head drive circuit 64. Further, the control unit 51 sequentially specifies the row and digit addresses of the image data memory 60 according to the movement amount detection signal from the encoder 39, and transfers the image 1' (! data) stored in the image data memory 60 to the data selector. 59 and output to the thermal head drive circuit 64 one row at a time.

The thermal head drive circuit 64 outputs a drive signal to the thermal head 21 according to data from the control section 51. Further, when the control unit 51 receives a one-line print command from the timing signal generation unit 52, the control unit 51 outputs the number of black characters in the print data, the head temperature from the temperature sensor 55, and the density adjustment volume 7.
The energization time for the thermal head 21 is set based on the adjustment value and the like.

In this way, the image data stored in the image data memory 60 is output one line at a time to the thermal spatula F21 for printing processing.

Therefore, by doing this, data on the white part of the document surface is extracted in advance in correspondence with the reading position, and this data is used to calculate the reference value for shading correction for each reading position, and this value is Since the read data from the actual document surface is compared as a threshold value and black and white binary data is obtained, effective shading correction can be obtained and good read data without the influence of shading can be obtained.
4. In addition, since all of this shading correction is processed electrically, the amount of light irradiated onto the document surface is reduced compared to conventional methods that use a shading correction plate or that use an anti-transparent film on the sensor side lens. In addition, it is possible to eliminate inconveniences such as a shortage of light and a decrease in lens resolution, and to stably read image data.

Note that this invention is not limited to the -1-2 actual flow side, and can be implemented with appropriate modifications within the scope of the gist.

[Effects of the Invention] According to the present invention, effective shading correction can be obtained by using a reference value for shading correction that is determined in advance based on the read data of the white portion of the document.
Good read data without the influence of shading can be obtained, and image data can be read stably.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the external configuration of an embodiment of the present invention;
Fig. 2(a) is a sectional view showing the internal structure of Fig. 1, Fig. 2(b) is a sectional view taken along line nn in Fig. 1(a), and Fig. 3 shows the main internal components. FIG. 4 is a block diagram showing the overall configuration of the electronic circuit, FIGS. 5 and 6 are diagrams for explaining the operation of the same embodiment, and FIG. 7 is a conventional image data reading device. FIG. l... Handy copy machine body, 2... Reading section, 3...
...Print section, 4...Power supply/reading/printing switch, 5a, 5b...Operation key, 6...Clear key, 7...Density adjustment volume, 71...Test mode/normal mode switching switch, 8...power LED
, 9...Memory LED, 10...Speed warning LED
, 11... light source, 11a... light source body, llb...
・Mirror, 12... Reading window, 13... Light guide, 14.
...Lens, 15...-dimensional image sensor, 16.
...Support body, 17...Inner frame, 18...Electronic component mounting section, 19...Battery storage section, 20...Circuit board,
21... Thermal head, 22... Ink ribbon roll, 23... Continuous feed roller, 24... Ink ribbon winding roll, 25a125b... Rubber roller,
26-30...Gear, 32...Notch, 33...1
Directional clutch, 34... Encoder disk, 35...
...Slit, 36...LED, 37...Photo sensor, 38...Through hole, 39...Encoder, 41...
...Print window, 42...Ink ribbon guide window, 4
3...Slit, 44...Ink ribbon guide, 4
5... Hinge, 51... Control section, 52... Timing signal generation section, 53... Speed detection section, 54... Switch group, 55... 7R degree sensor, 56... Amplifier , 57... D/A converter, 58... Serial/parallel converter, 59... Data selector, 60... Image data memory 61... Address counter, 62... Address selector, 64...・Thermal head drive circuit,
65... Selector, 66... White level data storage section, 70... Arithmetic section. Applicant's representative Patent attorney Takehiko Suzue Figure 3 (b) Figure (a) Figure 2 Sale 117J Daikai Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] A sensor for reading image data on a document by receiving reflection of light irradiated on the document surface; a storage means for storing data read by the sensor on a white portion of the document surface in correspondence with a reading position; and the storage means. A reference value generating means calculates and outputs a reference value for each reading position based on the stored data of the sensor, and a binary value is generated by comparing the image data of the document surface read by the sensor with the reference value of the reference value generating means. 1. An image data reading device comprising: data output means for outputting converted image data.