JP3706702B2 - Printer / scanner device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a printer / scanner apparatus that obtains a scanner function by mounting a detachable scanner head unit on a carriage of a printer, and more particularly to generation of a pulse signal for normalizing a clamp voltage.
[0002]
[Prior art]
Conventionally, as a general document reading apparatus used for a scanner, a facsimile, or the like, an apparatus using a reduction optical system as shown in FIG. 3 is known.
[0003]
This apparatus includes a light source 5 extending in a longitudinal direction for irradiating a document 6, a mirror 4 for bending an optical path to reduce the size of the entire apparatus, a lens 2 for imaging document information light, and a lens cos 4 power law for a white output waveform. A white reference correction plate (shading plate) 3 for correction and a CCD image pickup device 1 for converting optical information into an electrical signal are constituted.
[0004]
Further, an IC such as an A / D converter for A / D conversion is interposed before the voltage waveform output from the CCD image pickup device 1 is transferred to the image processing system.
[0005]
This A / D converter circuit is provided with a circuit for clamping the output from the CCD image pickup device 1 in order to adapt the voltage to an effective voltage range.
[0006]
[Problems to be solved by the invention]
However, in the above-described conventional example, it is necessary to continuously provide the line clamping pulse (LNST signal / LTCLK signal) at a short cycle in order to keep the clamp level at an appropriate level.
[0007]
In the embodiment of the present invention, the detachable print head / ink tank unit in the printer in the notebook computer (also referred to as a notebook computer) is removed and the scanner head unit is mounted. Therefore, there is a problem that the scanner circuit must be simplified due to the restriction of downsizing the outer shape.
[0008]
In addition, since the mounting contacts of the unit are the same, all the signal lines including the control system for the print head unit and color scanner head unit are shared, so a signal that generates a clamp when using the scanner (LNST signal) There is a restriction that must be shared with a signal (LTCLK signal) for latching print data when the print head unit is used.
[0009]
The present invention has been made under such circumstances, and the parts that can share signals under the condition that both the print head unit and the color scanner head unit can be driven are shared. Among them, the object is to secure the stability of read data without reducing the image reading area with a circuit configuration that requires further simplification.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, in the present invention, the printer / scanner apparatus is configured as follows (1), (2), (3).
[0011]
(1) A printer / scanner apparatus that obtains a scanner function by mounting a detachable scanner head unit on a carriage of a printer, and performs A / D conversion on the sensor output of the scanner head unit. Converter, a clamp circuit for level-shifting the sensor output to the input effective voltage range of the A / D converter, and a pulse signal for normalizing the clamp voltage of the clamp circuit when the carriage is stopped immediately before image reading. And a control means for controlling to be generated in the carriage constant speed operation range from the end of carriage acceleration to the start of image reading.
[0012]
(2) The printer / scanner apparatus according to (1), wherein the number of generated pulse signals for normalizing the clamp voltage is set for each image reading resolution.
[0013]
(3) The printer / scanner apparatus according to (1), wherein the scanner head unit includes an A / D converter and a clamp circuit.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to examples of notebook personal computers.
[0015]
【Example】
FIG. 1 is a perspective view of a color scanner head unit used in a “notebook personal computer” as an embodiment. In FIG. 1, there are a positioning hole 1B and a positioning groove 1C for positioning when installed on the carriage. It is the reference wall 1 that determines the posture in the reading direction, and its mounting position is determined by being shifted to a reference wall (not shown) on the carriage side. Reference numeral 20A denotes a connector portion which is an internal I / F for making electrical contact when mounted on the carriage.
[0016]
FIG. 2 is a view for explaining the arrangement of optical system components. In FIG. 2, reference numeral 3 denotes a three-color LED ([red] λ = 640 nm, [green] λ = 525 nm, [blue] λ = 470 nm, which is a light source, and is arranged in the reading width direction.
[0017]
A cylindrical rod lens 6 serving as a light condensing means is disposed in parallel with the LED 3 alignment direction in the vicinity of the LED 3 serving as a light source. The irradiation center of the LED 3 passes through the center of the lens action surface of the rod lens 6 and irradiates the surface of the original 20 obliquely.
[0018]
Reflected light from the original 20 passes through a field lens 7 that is a first imaging system lens whose optical axis center is provided in a direction substantially perpendicular to the original 20, and then is provided in a mirror provided in parallel with the reading width direction. 5, the advancing direction of the optical axis is bent by 90 ° to be a light beam substantially parallel to the document 20.
[0019]
Reference numeral 11 denotes an aperture, and the image plane of the field lens 7 which is the first imaging system lens is set to this position. An imaging lens (not shown), which is a second imaging system lens, is provided behind the aperture 11.
[0020]
The imaging position of the imaging lens is the position of the photoelectric conversion element 13 (Basis sensor). The arrangement of the imaging system lenses is set at a reduction ratio of 0.45158.
[0021]
FIG. 7 is a block diagram showing the configuration of the color scanner head unit. A monochrome Basis sensor (128 pixels) is used as the light receiving element. As a light source, R [red] / G [green] / B [blue] are provided with a total of five LEDs of two colors / two / one, and the RGB light source is switched. However, regarding the number of LEDs, there is no problem even if another number is used.
[0022]
FIG. 8 is a diagram illustrating an RGB LED driving circuit. In FIG. 8, IC is a 12 [V] 3 terminal regulator of the LED drive power supply. The 12 [V] power output here is supplied to each color LED. Each color driving circuit has a simple constant current circuit configuration, and red will be described. When 12V is divided by resistors R12 and R13, the divided voltage is between the base and emitter of the driving transistor Q1. The LED circuit current flows as much as the voltage and the voltage drop of the resistor R11. The Ron signal is turned off when the output is Low, and turned on when the output is High. In the case of Low due to the H / L signal, the resistor R14 is connected in parallel with R13, so that the divided voltage decreases and the LED drive current becomes weak.
[0023]
Next, the current values that flow through the LEDs of the respective colors are shown. Red / green indicates a strong current (Ron / Gon = High, H / L = High) of 10 [mA] and a weak current (Ron / Gon = High, H / L = Low) and 2.5 [mA]. The blue color is set to 20 [mA] with a strong current (Bon = High, H / L = High) and 5 [mA] with a weak current (Bon = High, H / L = Low). The difference in the current setting value is to set so that the level of the amount of light depending on the number and arrangement of the LEDs is close.
[0024]
As a color document reading method performed using a combination of the Basis sensor of the light receiving element and the RGB light source switching of the LED, it is performed by frame sequential three-pass reading by a sequential color method.
[0025]
As the operation, first, only the first color of the RGB LED light sources is turned on, and data for one row is acquired while moving the carrier by the reading width of the Basis sensor.
[0026]
Next, the line feed is not performed, and data at the same position is acquired by switching only the LED light source to lighting only the second color. For the same reason, the third color data is also acquired, and the reading of RGB color data for one line is completed, and a line feed is made to the next line.
[0027]
7 is a custom IC made exclusively for the color scanner head unit, and the function is as follows.
-Function to clamp the signal from Basis sensor-Peak search function to make the clamped signal the optimum range amplifier of A / D-1-5 times amplifier & gain control (256 steps)
-10-bit A / D converter function-Image processing function * Monochrome distortion correction * Edge enhancement * Reduction in column and line directions * Binary image data output * Multi-value (8-bit) image data output When reading a color image, RGB as color elements Since the output and temperature characteristics of the LED light source are different for each color, it is necessary to set a white reference.
[0028]
Therefore, when acquiring the white reference, the custom IC detects the peak of the white reference profile for each color signal from the Basis sensor, and can be set in 256 stages in order to set the reference in the A / D optimum range. Determine the gain.
[0029]
As white standard data,
・ 128 pixels * 10 bits as white data
・ 8-bit gain data
-As black data, 128 pixels * 8 bits
Are managed by RGB three color plus temperature data (2 bytes) and ID (2 bytes).
[0030]
A system of the entire notebook personal computer equipped with the color scanner unit having the above-described configuration will be described with reference to FIGS.
[0031]
FIG. 10 is a perspective view of the notebook personal computer of the present embodiment. The liquid crystal display device 101 can be opened and closed with a color display of 11.8 inches by TFT. The keyboard 102 can be operated when the liquid crystal display device 101 is opened. Although not shown, the printer unit is housed in the rear part of the main body.
[0032]
FIG. 11 is a block diagram illustrating a configuration of a notebook personal computer. As a drive source, there are an AC adapter (rated voltage 20 [V], 54 [W]) and a nickel hydride secondary battery (rated voltage 12 [V], 2700 [mA / h]). As built-in functions, there are peripheral device controllers such as a floppy disk controller (FDC), a hard disk controller (HDC), a keyboard controller (KBC), and a VGA controller (VGAC). Furthermore, a built-in printer is connected by an internal bus.
[0033]
A printer unit built in the notebook personal computer having the above-described configuration, a color scanner head unit that can be attached to and detached from the printer unit, and a print head unit (referred to as a BJ head) will be described with reference to FIGS.
[0034]
FIG. 4 is a block diagram. Three motors (carriage, line feed, auto sheet feed) control by printer CPU and controller, four sensors (home position detection, ASF position detection, paper feed detection, paper discharge detection), color scanner / The print head drive is controlled. The color scanner head unit and the print head unit are configured such that any one unit and the printer can be attached and detached. The joint has a contact electrode in the carriage portion of the printer, and is connected by pressure when the unit is mounted.
[0035]
As a mounting unit discriminating method, the carriage contact portion has a 2-bit head ID, reads the head ID after mounting, discriminates the scanner head unit from the print head, and associates the contents of the control pins.
[0036]
FIG. 5 is a diagram showing how to attach each head unit to the printer unit. Reference numeral 10 denotes a detachable color scanner head unit replaceable with a print head unit 30 for recording on a recording medium.
[0037]
The color scanner head unit 10 has the same shape as the print head unit 30 used for printing. Reference numeral 40 denotes a carriage having a contact portion for transmitting and receiving a read signal from the main body via the connector portion of the color scanner head unit 10.
[0038]
The read signal is processed by the CPU of the printer unit via the contact portion and the flexible cable 44.
[0039]
The carriage 40 is read by reciprocating along the slide shaft and the slide plate 47 between the frame side plate portions 45A and 45B. A drive motor 48 moves the carriage 40 via a belt.
[0040]
Further, as shown in FIG. 13, four types of speeds of the reciprocating operation of the carriage 40 are set according to the relationship between the accumulation time of the Basis sensor and the existing carriage speed table in the reading mode.
[0041]
The circuit configuration until the output signal of the Basis sensor is acquired as data will be described with reference to FIG.
[0042]
The output of the Basis sensor is AC connected with a 0.01 [μF] capacitor outside the portion surrounded by a dotted line, and a signal is applied to the “IN terminal”.
[0043]
A clamp voltage generated from the signal processing reference voltage adjusting D / A device 60 is supplied to the IN terminal by a line clamp signal. Although it is desirable that this potential is originally maintained even after the clamp signal is turned off, the electric charge is discharged within a few to several hundreds msec, and the potential drops from the original level.
[0044]
Therefore, in order to keep the clamp voltage in an appropriate state, it is necessary to add a line clamp signal with a short period.
[0045]
Using this signal as a trigger, read data for 128 pixels is output from the Basis sensor, passes through the voltage follower (A1), and then holds a signal processing reference voltage (5 [pF] capacity). In order to apply the voltage to the voltage follower [A2] and multiply the output by 0.8 by the dividing resistor, the data is captured for each pixel by the S / H signal (Signal Hold signal).
[0046]
After that, the signal level is made to fall within the optimum voltage range (1.4 to 0.4 [V]) for the A / D converter by passing through a variable attenuator that can control the gain variably up to 5 times range.
[0047]
The line clamp signal (hereinafter referred to as LNST signal) used for reading the signal from the Basis sensor is used as a latch clock signal (hereinafter referred to as LTCLK signal) shown in FIG. 9 when the print head is used. This signal is linked to the carriage movement of the printer, and print data (IDATA) for 128 dots for the monochrome head and 136 dots for the color head is serially transferred to the printing head in synchronization with the data clock (DCLK). Later, data is latched in the print head.
[0048]
Since the LNST signal and the LTCLK signal are shared, it is difficult for the printer carriage to generate the LNST signal during acceleration.
[0049]
FIG. 12 shows the operation of the carriage (also called carrier) of the printer. In this timing chart, the horizontal direction indicates time, and the vertical direction indicates the state of the carriage.
[0050]
The carriage first shifts from the stop state to the acceleration region, and then reaches the constant speed state. Then, after a specific interval is provided and stabilized, the image enters the image reading area or the printing area, performs a predetermined operation, then decelerates and stops. This basic operation also applies to both directions.
[0051]
The time interval between the acceleration reading area and the image reading area in the constant speed area or the portion before entering the printing area differs depending on the carriage speed depending on the reading resolution or the print designation mode.
[0052]
Originally, in order to stabilize the clamp voltage, 15 or more LNST signals are required before data acquisition.
[0053]
However, it is possible to generate 15 or more LNST signals in the carriage constant speed region before image reading because the carriage speed at constant speed is 3.9 [KHz] and the LNST signal interval is 256 [μsec]. Only in the case of resolutions of 360 dpi and 300 dpi, it is impossible to satisfy 15 shots in other resolutions (in order to make the physical position of the image reading area and the printing area the same, the left edge of the image reading position is It cannot be shifted.)
[0054]
For this reason, as shown in FIG. 12, the LNST signal is generated in the same period as the C region in the B region immediately after entering the constant velocity region in addition to the C region in which the LNST signal is being read.
[0055]
Further, an LNST signal is generated in the A region of the stop region immediately before acceleration so as not to be insufficient for normalizing the clamp.
[0056]
Since the number of LNST signals generated for the A and B regions is limited by the image reading resolution, it is set for each resolution.
[0057]
FIG. 14 shows the number of LNST signals set for each reading resolution in the present embodiment (the LNST signal generated for normalizing the clamp voltage is referred to as “dummy pulse” including the division generation portion).
[0058]
The dummy pulse is generated immediately before the above-described image reading and when the white reference is acquired.
[0059]
In the case of white reference acquisition, since the carriage is stopped, no special division is required, but in this system, 10 LNST signals are generated immediately before the white reference acquisition register is enabled in the carriage stop state. Then, the LNST signal is continuously generated 30 times from enabling to disabling.
[0060]
As described above, according to the present embodiment, the head image can be read without reducing the image reading range in spite of the restriction that the print head unit and the color scanner head unit share signals. Data can be secured stably from data.
[0061]
The present embodiment is an example in which the image reading direction is unidirectional, but the present invention can be applied to both directions. In the backward operation, a dummy pulse is generated with the carriage right end stopped.
[0062]
【The invention's effect】
As described above, according to the present invention, image reading is performed by generating a dummy pulse in the carriage constant speed operation range from the time when the carriage stops immediately before image reading and the time when carriage acceleration ends to the time when image reading starts. Data can be secured stably from the read data of the top image without reducing the area.
[Brief description of the drawings]
FIG. 1 is a perspective view of a color scanner head unit. FIG. 2 is a layout view of optical system parts. FIG. 3 is a perspective view showing a main part of a general document reading apparatus. Block diagram showing the relationship between the unit, print head unit, and printer unit [FIG. 5] Diagram showing the attachment / detachment state of the scanner head unit and print head unit to / from the carriage [FIG. 6] Diagram showing the sensor signal processing circuit FIG. 7 is a diagram showing a configuration of a color scanner head unit. FIG. 8 is a diagram showing an LED drive circuit. FIG. 9 is a timing chart of print data transfer. FIG. 10 is a perspective view of an embodiment. FIG. 12 is a block diagram illustrating the configuration of the embodiment. FIG. 12 is a diagram illustrating the operation of the carriage. FIG. 13 is a diagram illustrating the image reading mode. FIG. 14 is a diagram illustrating the number of dummy pulses generated for each reading resolution. Description of the issue]
10 Color scanner head unit 40 Carriage

Claims (3)

A printer / scanner apparatus for obtaining a scanner function by mounting a detachable scanner head unit on a carriage of a printer, and an A / D converter for A / D converting sensor output of the scanner head unit; A clamp circuit for level-shifting the sensor output to the input effective voltage range of the A / D converter, and a pulse signal for normalizing the clamp voltage of the clamp circuit when the carriage is stopped immediately before image reading and carriage acceleration A printer / scanner device comprising: control means for controlling to be generated in a carriage constant velocity operation range from the end of the operation to the start of image reading. 2. The printer / scanner apparatus according to claim 1, wherein the number of generated pulse signals for normalizing the clamp voltage is set for each image reading resolution. 2. The printer / scanner apparatus according to claim 1, wherein the scanner head unit includes an A / D converter and a clamp circuit.

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