JP3001948B2 - Contact image sensor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact type image sensor mainly used in an original reading information processing apparatus such as a facsimile or a copying machine.

[Prior Art] A contact type multi-chip image sensor is employed in a document reading information processing apparatus using a conventional short focus imaging element array. For example, in a document reading apparatus as shown in FIGS. 10 to 15, a transparent glass plate 201 in contact with the document surface is mounted on the upper surface of the box 200, and a document in which the emitted light 212 contacts the upper surface of the transparent glass plate 201. At a predetermined angle as reflected by the surface, the LEDs 211 are provided in the box 200 in a state of being arranged on the substrate 210, and the optical system 209 for passing the reflected light 213 of the transparent glass plate 201 and A plurality of line sensors 1 provided on a substrate 19 corresponding to this optical system are provided in a box 200. And in the above optical system,
For example, the above-described short-focus imaging element array represented by the product name “SELHOC lens array” (manufactured by Nippon Sheet Glass Co., Ltd.) is employed.

The line sensor 1 has a protective film on the substrate 19.
The substrate 19 is covered with 206, and the substrate 19 is
At 05, it is supported via a rubber plate 207. End plates 203 are attached to both ends of the box 200 with screws 204. In addition, the box 200 is provided with a connector 202 for input and output of a power supply and control signals outside the facsimile body or the like, for example.

The line sensor 1 has input / output pads 4 and 5 at both ends as shown in FIG.
Are arranged on the substrate 19 in a straight line from the Nth to the Nth,
By inputting a star signal through the input pad 4 and outputting an end signal through the output pad 5, the operation is sequentially performed in accordance with the arrangement order to read optical information. In this case, when an end signal is output via the output pad 5, the end signal can be input to the input pad 4 as a start signal for the next line sensor. As shown in FIG. 17, each line sensor 1 has a light receiving window 2 of 127 μm (for 200 DPI) or 63.5 μm (4
(In the case of 00DPI), where DPI is Dot
In addition to this, an area 3 on which a drive circuit of a line sensor, a shift register, a power input pad, a sensor output pad, and the like are arranged is provided on the substrate 1.

As shown in FIGS. 18 and 19, such a contact-type multi-chip image sensor (indicated by reference numeral 110) is, for example, fixed to a facsimile original reading position at a fixture 10 as shown in FIG.
Arranged via nine. Here, the facsimile body 100
A document insertion slot 103 is provided at the front edge of the
A slit 105 is formed in parallel with the guide stage 104 of 03, and a guide piece 106 for determining a document insertion position is slidably provided in the slit 105. A key board panel 101 is provided on the front upper surface of the facsimile main body 100.
And an operation message display section 107, and the document takeout port 102 is provided immediately after the operation message display section 107.

Then, the document 118 inserted from the document insertion port 103 reaches the feed roller 108 via the separating piece 117, passes therethrough between the platen roller 116 and the image sensor 110, and is discharged to the document discharge port 102. You.

At the rear of the facsimile main body 100, a roll-shaped recording paper 114 is stored, and the end thereof is a platen roller 115.
The recording head 111 records information at the position of the platen roller 115. In the figure, reference numeral 112 denotes a facsimile system control board, and reference numeral 113 denotes a power supply unit.

In such a configuration, when reading the original, the line sensor 1 sequentially performs the reading operation from the first to the N-th.
During this time, the read data outside the document separated by the guide pieces 106 is processed by the facsimile system controller and is discarded.

[Problems to be Solved by the Invention] However, in the above-described conventional example, when reading a document shorter than the length of the detection area of the image sensor, the reading is performed up to the place where there is no document as described above. The sensor 1 is driven, and wasteful power is consumed. Further, there is a dead time in reading the document, and further, a data processing program or a data processing circuit for discarding data in an area where the document does not exist is required.

Therefore, the present inventors separately proposed a contact type multi-chip image sensor having a configuration for solving this problem. In this image sensor configuration, first to Nth line sensors having input / output pads at both ends are arranged on a substrate in a straight line, a start signal is input through the input pad, and a start signal is input through the output pad. By outputting the end signal, the line sensors are sequentially operated in accordance with the arrangement order, and only the line sensors in the specified continuous arrangement are driven in the contact type multi-chip image sensor for reading optical information. Thus, the control circuit is provided so that a start signal can be selectively input from the outside to the input pad of the line sensor.

In this case, when an end signal is output via the output pad, the end signal may be input to the input pad as a start signal for the next line sensor.

In addition, the input pad of the previous line sensor and the input pad of the next line sensor are connected to the input pad of the selected line sensor so that the external start signal is input instead of the end signal. A selection circuit is provided between them.

Therefore, since the start signal from the control circuit can be selectively supplied to the input pad of each line sensor, the line sensor can be driven so that reading is not performed in an area outside the original, thereby wasting power and time. And the data processing system need not be complicated.

However, when such a control method is adopted for the contact type multi-chip image sensor, the following problem is newly caused. That is, when all of the line sensors read a document shorter than a document of a corresponding length, the output of the image signal is reduced. This will be described below.

As shown in FIG. 20, assuming that the total number of pixels of the contact type multi-chip image sensor is n, the image signal is n pixels in accordance with the clock after the start signal is input,
Output. The image signal output here is actually the image signal one cycle before. While outputting the image signal for n pixels, the image signal output by the next start signal is stored in the buffer. Will be done. That is, the time t from the start signal to the next start signal is the accumulation time.

However, when the document is shorter than the length of all the line sensors, a start signal is input to the line sensor corresponding to the start of reading of the document, and a reset signal is output to the line sensor at the position of the line sensor after the end of the document. if you did this,
Only the licensor having the m-th to l-th pixels out of the total number n of pixels is driven. This state is shown in FIG. One cycle of the clock here is k clocks, and k <n. That is, when a signal is input to a certain line sensor (the first pixel of the line sensor is m
An image signal is sequentially output from the m-th pixel in accordance with the clock, and the k-th clock, that is, the last line sensor to be driven (the last pixel of this line sensor corresponds to the first pixel) A signal for stopping driving is input immediately after the clock for outputting the image signal of the last pixel is input, and a start signal is input to the line sensor that has started driving immediately after that, and driving is started again. Storage time t ₁ until the start signal from the start signal is shorter than the accumulation time t previously described. It is well known that the output of an image signal becomes smaller as the accumulation time becomes shorter, and this solution is necessary.

Means for Solving the Problems The present invention has been made based on the above circumstances, and has N sensor chips each having a plurality of photoelectric conversion elements arranged in the main scanning direction. Each of the chips has an input terminal for inputting an operation start signal and an output terminal for outputting an operation end signal, and outputs an operation end signal from an output terminal of the i-th sensor chip to an input of the (i + 1) th sensor chip. A terminal is input as an operation start signal, and among the N sensor chips, the N
Only the input terminals of less than the number of sensor chips,
In a contact type image sensor configured to be capable of inputting an operation start signal, a selection circuit for selecting a sensor chip to start and / or finish driving in accordance with a document size to be read; A light amount adjusting circuit for adjusting the light amount of the light source so as to be suitable for the number is provided.

In this case, as an embodiment of the present invention, data of the size of the document is sent from the document size reading unit that reads the size of the document to the selection circuit and the light amount adjustment circuit, or the size of the document is read. It is effective to send data of the size of the document from the size reading unit to the selection circuit, and to send data of the number of sensor chips driven by the light amount adjustment circuit from the selection circuit.

Further, a switching circuit for interrupting an electrical connection from at least an output terminal of the i-th sensor chip to an input terminal of the i + 1-th sensor chip when an operation start signal is input to the (i + 1) -th sensor chip. Preferably.

[Operation] Therefore, the light intensity of the light source such as an LED can be adjusted according to the length of the document or the number of line sensors selected by the selection circuit based on the length of the document, so that the amount of light incident on the line sensor can be adjusted. A constant image signal intensity can be maintained irrespective of the length of the accumulation time.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 9. The same components as those of the above-described conventional example are denoted by the same reference numerals, and description thereof is omitted.

In the first embodiment shown in FIG. 3, the pixel pitch of the line sensor chip (photoelectric conversion element), that is, the interval between the chips is, for example, 127 μm (200 DPI). And the length in the longitudinal direction of the line sensor 1 at this time is 19.73 mm,
When a plurality of line sensors 1 are arranged in a straight line on the circuit board 8 as schematically shown in FIG. 3, the values are not divisible by 127 μm in order to correct the gap between the line sensors 1. . By arranging 13 line sensors 1, a document can be read up to a maximum B4 size (256 mm).

Now, assuming that the number of line sensors 1 on the circuit board 8 is N (13 in this embodiment as described above), each start input pad (input terminal) of each of these line sensors 1
4 can receive a start signal (operation start signal) from signal generation means (not shown) via each of the lines 1 _S , 2 _S , 3 _S. In particular, in this embodiment,
A start signal is input via the line sensor selection circuit 11 of FIG. The signal generating means includes a reading unit 14 for reading the size of the document when reading the document, and one of the line sensors 1 corresponding to the size of the document (in this embodiment, out of N line sensors). , I + 1st line sensor) to the start input pad (input terminal),
In order to input a start signal (operation start signal), in the line sensor selection circuit 11, the lines _1S , _2S , _3S
・ ・ Select one of them. In this embodiment, the end signal pad (output terminal) 5 of the line sensor 1 in the preceding stage
Is connected to the start signal pad 4 of the line sensor 1 at the next stage, and the start signal is externally supplied via the line (connected to the start input pad 4 of the (i + 1) th line sensor) selected as described above. Is input, i
An end signal (output signal) from an end signal pad 5 of each preceding line sensor is input to the input pad 4 from the (+2) th line sensor to the (i + m) th line sensor. Thus, the line sensors corresponding to the size of the document operate sequentially.

Now, for example, when reading a B4 size document, in the above embodiment, 13 line sensors 1 (that is, i = 0, m
= N = 13) must be driven. So, enter the external start signal on line 1 _S, do not enter a start signal to the other line. Therefore, the end signal from the end signal output pad 5 of the preceding line sensor 1 is input to the start signal input pad 4 of the second and subsequent line sensors 1.
Input as a start signal. The end signal is output when the reading of the line sensor 1 is completed or immediately before the reading is completed.

When reading a document smaller than the B4 size, for example, a document of A4 size (214 mm), the guide piece 106 is operated symmetrically to the left and right, and the second to twelfth hitting the size (that is, i = 1 , M = N−2 = 11) Line sensor 1
Only drive. Therefore, the first line sensor 1
Is not supplied with a start signal. Then, a start signal is externally input to the start signal input pad 4 of the second line sensor 1. In this embodiment, in order to prevent a start signal from being input to the thirteenth line sensor 1, a reset signal input pad (not shown) of the twelfth line sensor 1 is provided at a predetermined timing in this embodiment. A control circuit is configured so that a reset signal is input (that is, in this embodiment, a circuit that operates with a signal from the document size reading unit 14 as a signal generation unit, for example, includes a line sensor selection circuit 11) Good to do.
At this time, the end signal is not output from the twelfth line sensor, and the thirteenth line sensor is not driven. In the above usage mode, the end signal from the preceding line sensor 1 is input as the start signal to the start signal input pads 4 of the third to twelfth line sensors 1 as in the case of the B4 size described above. Is done.

Naturally, when reading a document smaller than A4 size, a start signal is input to the line sensor 1 to be started and a reset signal is input to the reset signal input pad of the line sensor of the line sensor 1 to be ended. Then, the next line sensor 1 is not driven.

As described above, according to the present invention, by providing the signal generation means for generating the operation start signal selectively input to the N sensor chips, it is possible to drive only an arbitrary continuous line sensor 1. it can.

In the above embodiment, since the insertion position of the document is set at the center, the guide piece 106 operates symmetrically. However, if the document insertion position is set with reference to the last line sensor 1 side, It is only necessary to consider which line sensor should input only the start signal, and the reset signal need not be used.

In the second embodiment shown in FIG. 4, when the end signal of the preceding stage is input as a start signal to the start signal input pad of the line sensor after the first driven line sensor, the external start Since a signal may be input and cause malfunction, the output of the preceding line sensor is input to the input pad 4 of the selected line sensor 1 so that the external start signal is input instead of the end signal. A switching circuit 6 is provided between the pad 5 and the input pad 4 of the next line sensor. For the switching operation of the switching circuit 6, a switching control signal can be input from the line sensor selecting circuit 11 to the lines 2 _SW , 3 _SW .

In the above embodiment, it is desirable that the switching circuit 6 is disposed immediately before each line sensor 1. This is because the start signal input pads 4 of the second and subsequent line sensors 1 sequentially become farther according to the order, the length of the wiring pattern on the circuit board becomes longer, and noise increases due to an increase in capacitance. .

In the third embodiment shown in FIG.
Is mounted on a substrate 15 on which only a wiring pattern is provided, and another substrate 16 is provided with a control circuit 17 including the above-described switching circuit, a transmission circuit relating to a start signal and an end signal, a selection circuit, and the like. The above-mentioned substrate 16 has the line
Lines 18 corresponding to 1 _S , 2 _S … and 1 _SW , 2 _SW … are provided. Here, an example in which the line sensor chips are arranged in a straight line has been described, but it is needless to say that the line sensor chips may be arranged in a staggered manner.

When the substrate 16 is provided separately as in the above embodiment, the configuration of the document reading device (contact type multi-chip image sensor) may be as shown in FIGS. 6 and 7. here,
The board 16 is attached to the bottom plate 205 via the screw 23,
The necessary electronic components are mounted there. It should be noted that a connector 202 'for a signal to the outside and a power supply is provided below the substrate 16.

Further, as the line sensor, the emitter of a bipolar transistor as described in U.S. Pat. An optical sensor of a type in which a capacitive load is provided to read an output signal from an emitter as a voltage is more preferably used.

As the recording means used in the information processing apparatus of the present invention, it is preferable to use a recording means whose typical configuration and principle are disclosed in, for example, US Pat. Nos. 4,723,129 and 4,740,796. According to this method, at least one of the electrothermal transducers corresponding to the recorded information and having a rapid temperature rise exceeding the nucleate boiling is applied to the electrothermal transducer disposed corresponding to the sheet or the liquid path holding the liquid (ink). By applying a drive signal, the heat generating element generates heat energy,
This is effective because the film is boiled on the heat-acting surface of the recording head, and as a result, bubbles in the liquid (ink) can be formed in one-to-one correspondence with the drive signal. By discharging the liquid (ink) through the discharge opening by the growth and contraction of the bubble, at least one droplet is formed.

Further, as a full-line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus, the length can be reduced by a combination of a plurality of recording heads as disclosed in the above specification. Either a configuration that satisfies the condition or a configuration as a single recording head that is integrally formed may be used.

In addition, a replaceable chip-type recording head that can be electrically connected to the device main body and supplied with ink from the device main body when attached to the device main body, or the ink tank is integrated with the recording head itself The present invention is also effective when a cartridge-type recording head provided in a fixed manner is used.

The document reading device is attached to a facsimile as indicated by reference numeral 119 in FIG. The other configuration is the same as that in the conventional description, and the description is omitted.

In the embodiment shown in FIG. 9, the switching circuit 25 on the circuit board 22 is used.
Is a multi-stage type, and determines the order of the line sensor which starts driving only by input of the switching control signal S from the outside. With such a configuration, a plurality of start signal input units are not required unlike the first embodiment, and the structure is simplified.

The contact type multi-chip image sensor configured as described above includes a control system as shown in FIGS. 1 and 2. That is, a line sensor selection circuit 11 provided on a substrate 10 on which the line sensor 1 is mounted is provided from a document size reading unit 14 for reading the size of the document by the guide piece 106 or the like.
The data is sent to (for example, the switching circuit 6 in FIG. 4) to determine a line sensor to be started and a line sensor to stop driving by a reset signal. at the same time,
A signal is sent from the document size reading unit 14 to a light amount adjustment circuit 13, and the light amount adjustment circuit 13 adjusts the light intensity of the light source 7 (for example, the above-described LED) for illuminating the document.

In the embodiment shown in FIG. 2, the signal of the document size reading section 14 is sent only to the line sensor selection circuit 12, and the line sensor selection circuit 12 determines the number of driven line sensors. The data is sent to the light quantity adjusting circuit 13 as data. Thereby, the driving of the line sensor and the driving of the light source can be controlled by the same signal,
The possibility that an erroneous signal is generated in the output of the image signal can be eliminated.

[Effects of the Invention] The present invention has been described in detail above. Since the start signal from the control circuit can be selectively supplied to the input pad of each line sensor, reading is not performed in an area outside the document. Thus, the line sensor can be driven, waste of power and waste of time can be reduced, and the data processing system does not need to be complicated. In addition, since the light intensity of the light source such as an LED is adjusted according to the length of the document or the number of line sensors selected by the line sensor selection circuit based on the length of the document, the amount of light incident on each pixel is increased or decreased. However, a constant image signal intensity can be maintained irrespective of a change in the accumulation time.

[Brief description of the drawings]

FIGS. 1 and 2 are block diagrams of different embodiments showing the configuration of a control device according to the present invention, and FIGS. 3 to 5 show respective embodiments of a contact type multi-chip image sensor according to the present invention. FIG. 6 is a schematic configuration diagram, FIG. 6 is a perspective view showing an embodiment of the document reading apparatus according to the present invention, and FIG.
FIG. 8 is a longitudinal sectional side view of a facsimile showing an embodiment using the original reading apparatus of one embodiment of the present invention, and FIG. 9 is another embodiment of a contact type multi-chip image sensor of the present invention. FIG. 10 is a perspective view of a document reading apparatus showing a conventional example, FIG. 11 is a perspective view showing a configuration of a line sensor on a substrate, and FIG. 12 is a CC of FIG. 13 is a perspective view of the substrate provided with the LEDs, FIG.
FIG. 15 is a cross-sectional view taken along the line BB of FIG. 10, FIG. 15 is a vertical cross-sectional perspective view of the same, FIG. 16 is a schematic configuration diagram of a conventional contact type multi-chip image sensor, and FIG. FIG. 18 is a perspective view showing the configuration of a conventional facsimile, FIG. 19 is a longitudinal sectional view taken along the line DD of FIG. 18, and FIGS. 20 and 21 are image signals. It is a timing chart regarding accumulation. DESCRIPTION OF SYMBOLS 1 ... Line sensor 2 ... Light receiving window 3 ... Area 4 ... Start signal input pad 5 ... End signal output pad 6 ... Switching circuit 7 ... Light source for original illumination 8-9 ... Circuit board 11, 12 ... Line sensor selection circuit 13 ... Light intensity adjustment circuit 14 ... Document size reading section 15, 16 ... Circuit board 17 ... Area 18 ... Line 19, 22 ... Circuit board

Claims (6)

(57) [Claims] An N sensor chip having a plurality of photoelectric conversion elements is arranged in a main scanning direction, and each of the N sensor chips has an input terminal for inputting an operation start signal and an operation end signal. And an output terminal for outputting
The operation end signal from the output terminal of the
An input start signal is input to an input terminal of the (+1) th sensor chip, and an operation start signal is sequentially input only to the input terminals of the N number of sensor chips out of the N sensor chips. And a selection circuit for selecting a sensor chip to start and / or end driving in accordance with the size of a document to be read and a number of driven sensor chips. The contact type image sensor including the light amount adjusting circuit for adjusting the light amount of the light source. 2. The contact type image sensor according to claim 1, wherein data of the size of the document is sent from the document size reading section for reading the size of the document to the selection circuit and the light amount adjustment circuit. 3. A document size reading section for reading the size of the document, sending data of the size of the document to the selection circuit, and sending data of the number of sensor chips driven from the selection circuit to the light amount adjustment circuit. The contact type image sensor according to claim 1, wherein: 4. When an operation start signal is input to the (i + 1) th sensor chip, at least an electrical connection from an output terminal of the (i) th sensor chip to an input terminal of the (i + 1) th sensor chip is cut off. 2. The contact type image sensor according to claim 1, further comprising a switching circuit. 5. An information processing apparatus comprising: the contact type image sensor according to claim 1; and a recording head for recording image information. 6. The information processing apparatus according to claim 5, wherein said recording head is an ink jet recording head which discharges ink by utilizing thermal energy.