What can you do with a scanner lamp? Light of PC peripheral devices

Kind people put me in the hands of such an old scanner, Mustek 6000p, a Windows 95 watch and large white plastic cases. As a rarity of great value, it would be a shame to throw it away without looking at the inside).

Vlasna, all of your electronics are sent to the smіtnik.

The illuminator of the scanning carriage is a primary cold cathode fluorescent lamp (CCFL), similar to that used in the backlit LCD matrix.

Carriage fee. The left side has a high-voltage inverter, so it’s time to try to light the lamp.

The left one has an integrated stabilizer 7812, designated Q8, so it’s easy to understand which paths the inverter generates life from. At its input, when the scanner is turned on, there is close to 14 volts, otherwise the lamp does not light up, how can I start it? Before connecting the board to the inverter, there are not so many tracks in the connector where the carriage board is connected to the main board, so it is possible that a switch is selected on transistor Q5, which starts the lamp.

We close the resistor R3 with tweezers, connecting it to the base of the transistor, for life, and... let there be light!

Having figured out how much we have cut all the signals, we solder a resistor-jumper between R3 and the main components.

... and the settings for a specific printer socket.

Let's take away such a neat inverter board and check it again.

To brighten the working area, it is, of course, not enough, but you can create a light box similar to the principle of a lamp in the refrigerator. As a donor to the body, it was no less than a summer Misha, the same age as the scanner. What would a reed switch be with normally closed contacts?

He has a bright look. It’s a pity that the buttons don’t have any functional value =)

Secure the lamp and body with double-sided tape. There is a magnet on the doors hard drive That's why there's adhesive tape. It’s not very aesthetically pleasing, but it’s not that beautiful.

To brighten a small space, more is enough

Dear reader, please note that in the photo of the board in the mouse case there is already a jumper instead of a stabilizer - there is no longer any need for the inverter to live with the home server, which is located on the same cabinet.

The information is given in a comprehensive manner!
The site administrator is not responsible for the possibility of inheriting the correct information provided.

Popular backlight lamps that are connected to USB- computer port,

- CCFL lamp;

Inverter ( CCFL ballast).

CCFL (Cold Cathode Fluorescent Lamp) lamp - tse cold cathode lamp, A thin (2...4 mm) glass tube filled with inert gases (neon, argon) with a small amount of mercury. The discharge of mercury vapor in the middle of the lamp tube is created by ultraviolet radiation, which causes the phosphor applied to the inner surface of the tube to glow, and The operating temperature of the lamp tube is close to 40°C. Such a lamp has a characteristic with a “negative support” - the firing voltage (about 1000 volts) is significantly greater than the operating voltage (about 300...500 volts). To keep the lamp alive, use a sinusoidal voltage with a frequency of 20...100 kilohertz.
The cold cathode is also used in neon lamps, in which an electrical discharge excites gas molecules, causing them to dissipate into visible light.

It should be noted that there are a lot of features CCFL power lamps and hot cathode lamps ( "hot" cathode fluorescent lamps, HCFL). butt HCFL lamps are compact fluorescent lamps (CFLs, compact fluorescent lamp, CFL) -

The main feature of these lamps is the presence of frying threads at the skin end of the lamp -
tension threads

Before starting the lamp and thread are heating up(sometimes called “hot cathode lamps”) and the electronics are replaced, which reduces the voltage required to fire the lamp. After starting the life lamp, the heating thread can be removed.

HCFL lamp life diagram

Looked below at the life for CCFL lamps can be used for HCFL lamps, vikorist and visnovka threads roasted so, nіbi tse elektrodi CCFL lamps

At the book The Art and Science of Analog Circuit Design - J. Williams (1998) harden that CCFL lamps in the most efficient way electrical energy at Svitlov's.

Inverter purposes for re-creation steady voltage 5 or 12 volts with a variable voltage of 500...1500 volts and a frequency of 30...80 kilohertz.

CCFL lamps are widely used in various electronic devices (LCD monitors and TVs, scanners, faxes...), and also in these devices they are used LED technology (light-emitting diodes).
Applications of inverters -
scanner with CCFL lamp and inverter (video vision) -

inverter for CCFL scanner lamp

CCFL monitor inverter Dell E172FPB -

Scheme CCFL The inverter is most often (Royer oscillator), wines in 1954 George H. Royer(patent US 2783384 A "Electrical inverter circuits"). In the descriptions of the statistics Royer, G.H., "A switching transistor DC-to-AC converter has an output frequency proportional to
the DC input voltage," AIEE Transactions on Communication and Electronics, Volume 74, July 1955, pg 322 to 326.

conceptual diagram of the classic Roer converter

Most of this circuit has a direct-current form of output voltage. There are a few shortcomings in modifying the resonant circuit of the Royer generator.

The Roer resonant converter circuit has been modified

or else

The Roher generator places a transformer with the primary winding located in the middle ( center tapped primary winding) (number of turns w1+w2) and winding the call of the bell (feedback winding) (number of turns w3). Also on the transformer there can be a secondary winding ( secondary winding), which determines the output voltage.
The two halves of the primary winding are connected to the main winding through two transistors Q1і Q2, included behind the circuit " push-pull The transistors are switched on through the alternating direct stream in the halves of the primary winding. The voltage from the positive gate winding is supplied to the base of the transistors, triggering the generation.
Vіdmіnnіst CCFL The inverter from the classic Roer generator is based on the presence of a capacitor. C1, connected in parallel to the primary winding, and simultaneously creates a resonant circuit behind it. As a result, the generator vibrates on the secondary winding with a sinusoidal voltage. The generation frequency is determined by the parameters of the transformer and the capacitor capacity. C1 and the parameters of navantazhenya. The fact that this generator vibrates a sinusoidal voltage means that such life circuits are widely used CCFL lamps On the right is that the light output of such lamps changes due to the presence of higher harmonics in the life voltage, and the Royer resonant generator ( resonant Royer) vibrates the sinusoidal voltage itself. The exact name of such a generator is " current-fed push-pull parallel-resonant inverter".

Research of such inverters is carried out h Linear Technology Corp. -

The axis is represented by the inverter circuit:

The operation of such generators is described in this book. - J Williams (1998) -

Inverter details:

transistors Q1і Q2 -
the most popular option is transistors (In monitor inverters) -
V CE SAT= 0.24 volts, VCE MAX= 80 volts, I C DC= 8 ampere h FE MIN= 200 ta f T= 330 megahertz

transistors (from the diagram from the site ludens.cl ) -
warehouses n-p-n transistor, VCE MAX= 60 volts, I C DC= 3 amperes h FE MIN = 700

transistors (M) (I used an inverter for the computer’s switching lamp for experiments) -
n-p-n transistor near the body TO-92 with a high coefficient of transmission of the stream and low pressure tension, VCE MAX= 10 volts, I C DC= 2 amperes h FE MIN = 200

transistors 2SD1627at SMD-vikonanny -
n-p-n transistor, VCE MAX= 25 volts, I C DC= 2 amperes h FE MIN = 3000!!!

transformer -
butt transformer - XFORM INVERT 9.5uH EE19
description of transformer type EE19 -

Apply the number of turns:
w1 = w2 = 7, w3= 2, secondary winding – 142 turns.

throttle L1 -
an important element of the scheme,
Inductance ~330 µH with permissible flow up to 1 ampere;
in my inverter, the choke is a winding of 60 turns of copper wire with a diameter of 0.2 mm, wound on a dumbbell-like core

resistor R1 -
reference 1...2.7 kOhm (my inverter has 1.5 kOhm (brown-green-red-gray dark brown)).

capacitor C1 -
Bazhano polypropylene ( MKP) (visit large jets) with a capacity of at least 10 nanofarads at a voltage of hundreds of volts
examples of MKP capacitors for 27 and 330 nanofarads:

With an increased capacity of the capacitor, the resonant frequency of the circuits changes, for example, with a capacity of 1...2 microfarads, the generation frequency shifts in the audio range.

At correct work circuits on the collectors of transistors operate with a half-wave rectified sinusoidal voltage.

The main intervening factor in the scheme is the quantity voltage on collectors transistors, which can reach 60 volts with a live voltage of 24 volts.
In the inverter for CCFL lamps sequentially from vantage ( CCFL lamp) turns on the ballast capacitor (my inverter has 22 pF x 3000 volts, another option is 4.7 nanofarad x 1500 volts). By changing its capacity, you can adjust the flow to suit your needs.
An electrolytic capacitor, for example, 22 microfarads at 25 volts, can also be connected to the inverter input.

In the project vikorist the scheme is coming for the life of Geiger physicians:

The device has a microcircuit LM2575T-Adj- pulsed voltage stabilizer with adjustable output voltage. The conversion frequency (52 kHz) is determined by the generator. The microcircuit is suitable for input voltages up to 40 V. The output voltage regulation interval is 1.2 ... 35 V with an input voltage of up to 1 A. Minimum difference between the input and output voltage - close to 2 V Є protection due to temperature excess, short shimmer in Lanzyuzi navantazhenya and perevantazhenya along the strum.
Pinout of microcircuits:
1 - input voltage ( V IN)
2 - exit ( OUTPUT) - display of the internal key emitter
3 - earth ( GND)
4 - entrance of the gate link ( FEEDBACK)
5 - input to the on signal (grounding = 0 ... 1.4 volts)/off signal (1.4 volts... life voltage) ( ON/OFF)
Support voltage V ref is 1.23 volts.

Cory's message:
- website ludens.cl (discovery of life schemes for fluorescent lamps)

The problem of a non-functional scanning module in high-function Hewlett Packard LaserJet 3380 devices is one of the most widespread and is widely discussed and discussed among fakivki in all Internet forums. This problem has not been explained, melodiously, by the most experienced fakhivet, or by the one who has never dealt with these devices before. The important idea in this entire discussion is that the problem cannot be solved in any other way than by replacing the entire scanning module. Perhaps you will find the key to the most common problem of a non-working scanner in the LJ3380 in this publication.

You can see a number of problems characteristic of the HP LJ3380 MFP and the appearance of the scanner module:

- Program support for the device;

- daily movement of the scanning carriage when the scanning lamp is turned on;

- adjustments for the moved carriage;

- the number of days of scanning lamp illumination;

- the device is ready every day, even though the scanning lamp is moving in and the carriage is moving.

Let's try to give a short description of the skin problem, but to guess such situations, if the cause of the problem is broken cables and defects, we won't guess - the stench lies on the surface.

Software protection options for the device

This problem is actually related to the compromises made by the manufacturer at the time of creation of the hardware software (Firmware). The main problem is expressed by the HP company itself, and it involves the need to replace the Firmware from the old version with a new one, which includes all the bugs. HP has posted this software patch on its official website in full necessary instructions, then. made it accessible to any kind of machine. However, “reflashing” the software of the device helps in several situations and cannot be considered as a serious approach to solving a serious problem. Of course, replacing the Firmware gives a result, and it can be seen as the first stage of the service agent’s work, but putting serious hopes on it is still not a good idea. How to “reflash” Firmware has already been discussed many times in various devices, and this information is easy to find on the Internet.

Number of days of movement of the scanning carriage

When the machine is turned on, the lamp that scans begins to glow, and the carriage becomes indestructible. Therefore, the carriage cannot recognize the cob scanning position, which, of course, must be carried out until the cutting appears through the singing period. This behavior indicates a malfunction of the carriage drive system, in which you can see the motor and the motor driver microcircuit. The ease of use of these elements is high, which is confirmed by practical evidence. About how to diagnose this problem, as well as about the principles of operation of the carriage drive system and circuit design, we will read in one of the next issues of the magazine.

Removal of the moved carriage

Incorrect movement of the carriage, which may be due to the fact that it begins to collapse in the wrong direction, does not appear at the exit position, or may be caused by a malfunction of the motor itself and the driver circuits, or a malfunction of the CCD.

Lamp light intensity

This problem lies in the absolutely poor behavior of the scanner, but in the resulting result. If the lamp does not light up when the device is turned on, although the carriage moves, there may be a number of reasons:

- malfunction of the lamp itself;

- malfunction of the lamp inverter;

- Malfunction of the voltage regulator for the inverter.

To address this situation, we believe the information provided below will help.

Availability of the device

If the machine notices the heating of the lamp that is scanning, while the lamp lights up and the carriage moves, it can be detected as the lamp is losing tension and needs to be replaced. However, the main problem, however, may be due to a slight increase in voltage that is applied to the lamp, which leads to increased brightness. You can increase the brightness of the lamp by removing the material and pointing it lower.

Also, in some cases, a problem with the performance of the scanner may be caused by a malfunction of the circuits that form the voltage of the scanning lamp. For the HP LJ3380, the scanning lamp is a cold cathode fluorescent lamp (CCFL), which requires the application of high frequency and high voltage power. To form this voltage, there is a special circuit that will ensure the conversion of low-voltage constant voltage to high-voltage voltage. This circuit was called the inverter. At the inverter warehouse, the main elements can be seen as a pulse transformer and a pair of transistors. The inverter looks like a framed cardboard, molded onto a carriage that scans, and is located below (Fig. 1).

Fig.1

The inverter connects to the PZZ payment for an additional connector J1 (Fig. 2), through which a voltage of 10.5V - 11.5V is applied to the inverter.

Fig.2

However, the PZZ board is tested only because the board is suitable for which wire paths pass through. The constant voltage supply for the inverter itself is located on the formatter board. The diagram of inter-board connections, which are part of the life of the inverter, is presented in Fig. 3.

Fig.3

This circuit will help you control the supply of live voltage to the scanning lamp, starting from the Engine Controller board.

As we have learned, the lifespan that forms the voltage for the inverter is mounted on the formatter board (div. Fig. 4).

Fig.4

This device is a DC-DC converter that ensures the conversion of a constant voltage of +24V to a voltage of approximately +11V. The appearance of DC-DC conversion is due to the fact that the power supply unit of the device does not have such a rating, and, in addition, there is the need to supply power supply to the inverter so that the lamp can be turned on and switched off from the power supply and the moment.

The DC-DC converter is a buck-type pulse converter, its circuit is shown in Fig. 5.

Fig.5

The main element of the redesign is the key regulator microcircuit – LM3578AM. Functional block diagram These microcircuits are presented in Fig. 6.

Fig.6

The purposes of these contacts are described in Table 1.

Table 1.

№	Sign.	Description
	IN -	Input of inverting internal comparator.
	IN +	Do not invert the input of the internal comparator.
		Contact for connecting a frequency-setting capacitor.
		Zagalna.
		Emitter of the internal output transistor.
		Collector of the internal output transistor.
		Input of comparators in the stream. The contact can be used to control the interconnection of the circuit, both the internal switching transistor and any pulse switch covered with a microcircuit.
		Live voltage input (2V to 40V).

The LM3578AM microcircuit is a key regulator with the ability to regulate the width of the output pulses. The HP LJ3380 scanning lamp voltage regulator circuit has a vicoristan microcircuit for the so-called Buck regulator. As a power switch that operates in pulse mode, the internal transistor of the microcircuit is switched, and the pulses are taken from its emitter, which is supported by pin.5. A voltage of +24V is applied to the collector of the transistor (pin 6), and pulses with an amplitude of +24V are formed on its emitter. Further, these pulses are smoothed out by inductor L1 and capacitor C139, as a result of which a constant voltage of approximately 11V is output. The CR5 diode will provide support for the current flow during the period when the internal transistor microcircuits are closed.

The flow protection of the internal transistor (and also by pressing the switch) is provided by resistor R117. The voltage drop across this resistor (between pin 8 and pin 7) indicates the magnitude of the collector flow of the transistor and is estimated by the internal flow comparator. The maximum flow of the transistor is not responsible for exceeding the value of 750 mA. Current exchange is required when a voltage drop of more than 110 mV occurs across resistor R117.

The supply voltage of the microcircuits in this circuit is based on +24V. As soon as the voltage appears on pin.8, the internal clock generator of the microcircuit will start, which can be guessed by the presence of a saw-like voltage on pin.3. The frequency of the saw blade is determined by the capacitance of capacitor C133. The smaller the capacitance of the capacitor, the higher the frequency of conversion. U Zagalny Vipadka The capacitor capacitance must be in the range of 1 nF (approximately 100 kHz) to 100 nF (approximately 1 kHz).

In addition, when the microcircuit is started, a load of 1V may be established on its input contacts (pin 1 and pin 2). It is formed by internal microcircuits, and this also speaks about the serviceability of the microcircuits.

The start of the conversion is ensured by the formatter microcircuit (U14) by forming the signal high level, which is applied to resistor R170. Since the formatter is a microcircuit in a BGA package, it was not possible to determine exactly which contact generates the signal that controls it. If we knew for sure, then it’s all one thing, it’s impossible to control this signal on the microcircuit, and therefore, to diagnose the signal, it’s best to use resistor R170. At the moment when the lamp starts to light, the formator sets the core signal to a high level, which can be monitored using an additional tester or oscilloscope.

Stabilization of the output voltage is ensured by the coilover linkage, which consists of resistors R179 and R178.

Diagnosis of circuits

Diagnostics of the scanning lamp regulator is carried out by checking the signals at control points. These control points are set by the driver himself in order to perform diagnostics based on the problem that has occurred, as well as on the regulation of the controller circuit diagrams and other information provided. Tim no less, we still once again have the utmost respect for those signals and points of their control, which will help formulate the correct concept.

1) It is necessary to check the presence of +24V voltage on pin 8 of the LM3578AM regulator microcircuit (U19). The lack of voltage indicates a malfunction of the device’s life-saving device, or the FU4 slave. However, such problems cannot be attributed to other mechanisms of the device. In addition, the lack of voltage may result from a malfunction of the U19 microcircuit itself (internal short circuit to ground), and this problem is associated with strong heating of the microcircuit body or its physical nuvannyam.

2) The saw-like voltage on pin 3 and the presence of a bias voltage of 1V on pin 1 are monitored. that contact 2. microcircuits LM3578AM (U19). It’s hard to talk about everything, most of all, about the malfunction of the microcircuits. However, due to such problems, there is no need to check capacitor C133 for breakdown.

3) The presence of +24V voltage in pin 6 of the LM3578AM regulator microcircuit (U19) is monitored. The lack of voltage speaks for everything about the malfunction (cut) of resistor R117.

4) It is necessary to monitor the appearance of a high level signal (close to +3.3V) on resistor R170 (on the side of the formatter microcircuit) within an hour after turning on the device. The absence of a signal indicates a malfunction of the formatter. The following also applies to the reference of capacitors C134 and C132, as well as resistors R170-R173.

5) The presence of forward pulses on pin 5 of the LM3578AM microcircuit is monitored. The number of impulses to talk about:

- Malfunctions of microcircuits;

- malfunction of the CR5 diode (“breakdown”), in which the breakdown of the CR5 diode is accompanied by a strong breakdown of the microcircuit housing;

- malfunction of capacitor C139 (vitik), which is also accompanied by the heating of the microcircuit housing.

6) The presence of constant voltage on capacitor C139 is monitored. It may be in the range of approximately 10.7 to 11.7 V. The constant voltage indicates that the L1 inductor is broken. If the voltage rating does not correspond to the specified range, it is necessary to check the capacitors C139 and C142, resistors R178 and R179, as well as the regulator voltage connector to J2 on the formatter board). In addition, a decrease in the output voltage of the regulator can absorb the increased support of resistor R117.

The most common scanning lamp problem

As we have already said in the beginning, one of the problems with the device is that it cannot enter the ready mode if the lamp starts to glow normally. This problem is often associated with a malfunction of the scanning lamp itself, the intensity of the light flow changing over time. The degradation of a CCFL lamp is a natural process and it is impossible to avoid it. Otherwise, it is necessary for a Swede to wear out this lamp, perhaps through an incorrectly selected operating mode, then. through adjustments in the opening of the voltage regulator or the replacement of unclear lamps. You can come to terms with this by replacing the entire scanning unit, or decommissioning the device, or try changing the operating mode of the lamp, which will increase its brightness. Of course, an increase in the brightness of the lamp will lead to even greater degradation of the lamp, otherwise, fatigue, it may be possible to operate the device for several hours. You can increase the brightness of the lamp in a number of ways:

- Increased value of resistor R179;

- Changed the value of resistor R178.

Changing the values of resistors R178 and R179 changes the value of the gate signal at the beginning of the change, which automatically leads to an increase in the frequency of pulses, then. until the output voltage increases.

The design of any device, especially one that includes both electronic and mechanical elements, may be full of hidden secrets and mysteries, which it is important to figure out for yourself. Flatbed scanners are just such an option. At first glance, the scanner's device does not seem particularly foldable: the body has numerous slots and a couple of buttons, there is a noticeable tablet cover, and one on which originals are placed for scanning. Regardless of how the “state” works, and what the numbers of its specification mean, it seems to be a completely different story. In order to learn to navigate the numerical models of scanners presented today on the computer market, it is necessary to identify the real values of the characteristics indicated by the manufacturers. To make this article more informative, let’s look at the design of the scanner, as it seems, from the literal meaning of the word “let’s figure it out.”
Well, perhaps, from the most important element of any scanner - the light-sensitive matrix, which is like its “eye”.

Matrix

So. The matrix itself is the most important part of any scanner. The matrix transforms changes in color and brightness of the light flow that is received into analog electrical signals that will be understood by only one of our electronic friends - the analog-to-digital converter (ADC). From this point of view, the ADC can be aligned with the transfer guide, its constant companion. Only people, like anyone else, understand the matrix, and some processors and controllers cannot parse their analog signals without first converting them. Only those who are able to ensure the work of all their digital colleagues will receive only one word - two zeros and one. On the other hand, you can take any processor that transforms or accelerates it, illuminate it with the brightest light and observe any reaction for a long time until you get it right. The result is known in advance - it will be zero, since some other electronic components of the scanner are not sensitive at all. As luck would have it, all stinks are invisible to the people. Insha rich – matrix. The light stream falling on its surface literally “knocks out” the electrons from its sensitive cores. And the brighter the light, the more electrons will accumulate in the accumulations of the matrix, the greater will be its strength if they rush in an uninterrupted stream to the exit. However, the power of the electron flow on the board is extremely small, so it is unlikely that the most sensitive ADC will “sense” them. Moreover, upon exiting the matrix, a booster checks on them, which can be compared to a majestic mouthpiece, which transforms, figuratively, the squeak of a mosquito from a bushy lilac. Strengthen the signal(still analog) “summon” the transformation, and give the skin electron digital values, hence the force of the stream. And then... Then the electronics will be digital information, which will be processed by other facists. Working on image creations will no longer require a matrix.
Ale lishimo zagalni merkuvannya. Let's look at the practical side of things. Most current scanners for home and office are based on two types of matrices: CCD (Charge Coupled Device) or CIS (Contact Image Sensor). This fact gives rise to two diets in the minds of koristuvachs: which is different and which is better? It is noticeable that the body of the CIS scanner is flat, aligned with a similar CCD device (its height should be close to 40-50 mm), unlike the other one, it is much more foldable. The answer here needs to be argued in order to avoid the avalanche of chewed-up arguments like “why is this the best?”, “Why is the wine the best?”
First, let's take a look at the main advantages and shortcomings of these two classes of scanners. For clarity, I call them on a small sign:

The CCD scanner has a greater depth of sharpness, lower than its CIS counterpart. This is achieved through the design of the lens and mirror system.

For the sake of simplicity, the little one has only one mirror daubed on it,
Same as a typical scanner, there are no less than three or four

Scanners with a CCD matrix are wider and larger than CIS devices. It should be explained that scanners are most often purchased not only for digitizing sheets. text documents, as well as for scanning photographs and color images. In this case, you want to produce a scan with the most accurate and reliable transmission of colors, and in terms of light sensitivity, a CCD scanner conveys colors, highlights and shades more efficiently , lower CIS scanner. I mean that the difference between the range of color shades that are distributed by standard CCD scanners is close to ±20%, while for CIS machines the difference is less than ±40%.

Schematic representation of the CIS sensor

The CIS matrix consists of a LED line that illuminates the surface of the scanned original, microlenses that self-focus, and the sensors themselves. The design of the matrix is even more compact, so the scanner, which houses the contact sensor, will soon be much thinner than its CCD counterpart. Moreover, such devices are famous for their low energy consumption; the stench is practically insensitive to mechanical infusions. However, CIS scanners are often found in other countries: the devices, as a rule, are not equipped to work with slide modules and automatic document feeders.
Due to the peculiarities of the technology, the CIS matrix maintains a relatively small depth of sharpness. For leveling, set the sharpness depth of CCD scanners to ±30 mm, CIS – ±3 mm. Otherwise, it seems that when you place a book on the tablet of such a scanner, you take off the scan with the dark brown spread out in the middle, then. there, where the original does not stick together. With a CCD camera, the whole picture will be sharp, the parts in its design are the mirror system and the lens that focuses. However, the optical system itself is bulky and does not allow the CCD scanner to reach the same compact size as its CIS counterpart. However, on the other hand, the optics themselves provide an obvious benefit. I respect you, your attention to optics is very high, and you are sensitive to the fact that in some models of scanners, there are too many “plastic mirrors”, to say the least, “victims”. ;)
In terms of separate production, CIS scanners are also not a competitor to CCD. Nowadays, several models of CCD scanners for home and office have an optical separation of approximately 3200 dpi, while CIS devices have an optical separation of around 1200 dpi. It’s not a good idea to remove the CIS technology from shields. All technologies are developing rapidly. Scanners with a CIS matrix have found their place where it is necessary to digitize books and sheet originals. The fact is that these scanners will always receive data via the USB bus and will not require an additional device for life, like other laptop computers. You can digitize the original and translate it into a text file, regardless of proximity electrical lines, which allows you to flatten your eyes onto a number of short sections of the contact sensor. Therefore, you can receive information about “which scanner is shortest” based on your specific queries.

The most important element of the scanner is the CCD matrix

When you take a larger photograph, you are looking at the CCD matrix, which is the “great microcircuit” and finally. Here and focus, make it light like the original. The matrix does not work for the entire hour until the carriage with the moving carriage, which is driven by a rotary electric motor, goes along the side of the tablet until the end. I appreciate that the hidden distance of the gun carriage behind the straight “Y” is called the sampling frequency or the mechanical separation of the scanner (we’ll talk about that a little later). In one cycle, the matrix completely covers the horizontal line of the tablet, which is called a raster line. After the end of the hour sufficient to scan one such line, the carriage of the rolling block moves a short distance, and the time has come to scan the leading line, etc.

Side view of the CCD matrix

In the side view, you can note two primary screws that play a “delicate” role. With their help, at the stage of folding the scanner, the matrix was accurately adjusted (return also to the U-like slots in other payment looks like an animal), so that when falling on it, the light from the mirrors falls evenly over its entire surface. Before speaking, if one of the elements of the optical system is skewed, the computer causes the image to appear “dark.”

Larger image of part of the CCD matrix (macro image
divided into digital Canon camera EOS D60)

The larger photo of the CCD matrix clearly shows that the CCD matrix is equipped with a wet RGB filter. It itself is the main element of the system of sub-colors, about which there is a lot to say, but few people show how it really works. Many observers are bound by standard formulations: “a standard flatbed scanner uses a high-quality light source, a color subdivision system, and a charge-coupled device (CCD) to collect optical information about the object being scanned.” In fact, light can be divided into different color warehouses, and then focused on matrix filters. So the most important element of the color system is the scanner lens.

The scanner lens is really not as great as it looks
photographs

Frame

The scanner body is designed to be sufficiently rigid to prevent possible distortions in the design. Insanely, most beautifully, since the basis of the scanner is a metal chassis. However, the housings of most scanners for home and office that are produced today are made from plastic, at a cost of reduced durability. In this case, the necessary value of the structure is given by stiffening ribs, which can be aligned with the ribs and side members of the airframe.

Refurbishment of the main functional components of the scanner

An important element of the housing is the transport lock, which, if pressed, will prevent the carriage that is scanning from damage when transporting the scanner. It is important to remember that before using any scanner equipped with such a lock, you will need to unlock it. Otherwise, the mechanisms of the device can be damaged. In principle, manufacturers emphasize the respect of buyers on this small nuance with bright stickers with consistent warnings.
The actors respect that the body cannot be fused to the brightness of the scan. However, this is far from the case. On the right, the optical system of the scanner does not tolerate sawing, so the body of the device is sealed, without any gaps (technological ones). I have been repeatedly tortured by models that were not exposed to such abuses. If you happen to get a scanner, I recommend that you take it seriously.
Also, when purchasing a scanner, pay attention to the flexibility of a separate tablet cover. Such power of the apparatus is especially useful for the scanning of such originals as books or magazines.
The edges of the tablet are due to the gentle slope - this makes it easier to preserve the smoothness of the original from the warehouse. In addition, there is no gap between the edge and the tablet, which would have gone against the original. Also pay attention to the presence of markings on the perimeter of the tablet.

Keruvanya block

All scanners are scanned from a personal computer prior to any connection, and the necessary adjustments before scanning are set in the window of each program. Therefore, scanners for home and office use a powerful control unit. However, many selectors go ahead of the most prepared computers and install (on the front panel) a number of “quick scan” buttons.

Quick scan buttons are an element you can do without

On hovering over the photo you can see that the skin button resembles an icon. Typical quick start functions require the launch of a standard scanning operation, output to the printer, and then sent via email, fax, etc. It is understood that for this and other buttons specific scanning speed parameters are set. At the same time, pressing the same button will immediately launch programs on the computer (such as programs) that indicate the operation that is clicked. Please note that not all SOHO scanners contain a power control unit, but in professional devices such elements are daily and ready.
Some printers “sin” because they turn off a number of adjustments from the scanner driver, which, in my opinion, most cross-border users do not need. So, for example, Hewlett-Packard SOHO scanners have the ability to change gamma correction, use ICC profiles, and much more. However, Hewlett-Packard itself, like no one else, loves to “pamper” customers with a row of quick-scanning buttons.

About dzherela svetla

Absolutely the skin scanner has its own illuminator. This is the name of a small and heavy module that requires the scanner lamp to be turned on and off (or the one that replaces the lamp). In CIS scanners, the light was designed to have a single LED line, which is why this class of devices consumes so little energy.
Original CCD scanners are equipped with a cold cathode fluorescent lamp as standard. Its light is thousands of times brighter than LEDs. But in order to turn on the gas in the middle of the lamp, you need to apply a very high voltage to its input. It vibrates a large block called an inverter.

A high-voltage module is required to power the lamp

The inverter moves the voltage from five volts to several kilovolts, and also converts steady stream at zminny.

There are three main types of lamps that are used in scanners:

xenon gas discharge lamp (Xenon Gas Discharge);
fluorescent lamp with a hot cathode (Hot Cathode Fluorescent);
cold cathode fluorescent lamp (Cold Cathode Fluorescent)

However, scanners for home and office use have little reason to use cold cathode lamps.

Cold cathode lamp

The scanner lamp is mounted on the plastic chassis of the carriage, which scans, directly above the pick-up device. The highlighter itself takes the form of a reflector (an effective “selector” and light picker) in the shape of a high-power mirror. The light will shine brightly to highlight the object clearly on the tablet. Having appeared as the original on the glass, the light passes through the crack of the frame (in the photograph I saw the outline in a black color) and is received by the first mirror of the optical system that is found.
Among the obvious advantages of a cold cathode lamp, one can determine the long service life of 5000 - 10000 years. Therefore, before speaking, in some scanners it is not necessary to turn on the lamp after the scanning operation is completed. Moreover, the lamps do not require any additional cooling and are even cheaper during production. With a few shortcomings there will be even more inclusion. The typical heating time for the lamp is 30 seconds to several minutes.
The lamp has a significant influence on the scanning result. With a slight glance at the characteristics of the jig, the light changes and falls on the normal matrix of beats in the original light flow. That's why you need to turn on the lamp for a long time before going to bed. I appreciate that some drivers allow you to change the startup time, since the accuracy of digitization is not so important (for example, when scanning text information). I will add, in order to compensate for the lack of attention to the characteristics of the lamp (which will inevitably occur during heavy use of the device), the scanners automatically carry out a self-calibration procedure using a black-and-white target located in the middle of the body.

It is clearly visible in the photograph, as if under the infusion of light with linoleum
The plastic housing and the calibration target darken for an hour

The follow-up scanner is not to blame. On the photo, you can clearly see the color mark, behind which the scanner softens the colors before scanning, compensating for the “old” lamps. Here you can also see that over time it darkens not only the inner plastic case is permanently illuminated by the lamp, but also the calibration metal itself. This, in your own way, should lead to the emergence of colors and an increase in color problems.

A cold cathode lamp looks like a daylight lamp
light... just a little

The inverter and cold cathode lamps can be used for
judge the table lamp

In the photo you see a bad scanner lamp. ;) The inverter module is connected to a standard computer unit, for which the wiring was soldered to the adapter before the payment. In principle, if any kind of ruler is present here, then it will be possible to use a dirty and bright table lamp.

Robot ADC

Who helps the scanner processor “find the correct language” from the matrix? Firstly, an analog-to-digital converter deals with the conversion of analog signals into digital form. This whole process can be seen as follows. Initially, the ADC seems to “refer” to the input voltage, guessing the salesperson in the store selects a set of standard weights for the same product. Then, if the voltage is adjusted, the ADC presents the data to its “boss”, or to the processor, and also in the form of numbers. And as a result, everyone is happy.
How can you find yourself in the role of a processor and see what is generated at the output of the ADC when changing the input voltage? For example, we supply 4 Volts at the input, then 9 Volts. The following variations of numbers appear at its output: first 00000100, then 00001001. double code This is the number 4 and 9. The number of zeros and ones that the ADC expresses is the actual value - this is the number of bits that is expressed in the bits. This parameter is capacity of the converter This is very important for the scanner, and it also characterizes the accuracy of the input signal.
Today, inexpensive scanners can be found on store shelves that perform scanners with a capacity of 24 to 48 bits. Theoretically, it is better to choose the scanner that has the largest capacity. With this in mind, there is one subtlety to note: sometimes manufacturers write “48 bit” on the boxes, but here they specify in a different font: “software 48 bit, hardware 36 bit”. This means that a large number does not have anything to do with the precision of the ADC installed in the scanner, and the actual bit capacity is 36 bits. Focus on it yourself. It should be noted that in home practice the differences between the results of 36 and 42-bit scanners are practically indistinguishable (the human eye is currently separated by approximately 24 bits of color images, so close to 16.7 million). In our case, the variety of colors and depth of color are the same. And even the transformation of the image determines nothing more than the color of the points from which the image is formed. The higher the resolution of the scanner, the more efficiently the scanner can transmit the color of the skin of the image. Apparently, the image will be more similar to the original.

Processor

Today's scanners are equipped with specialized processors. Before setting up such a processor, it is necessary to organize the activities of all nodes and nodes, as well as formulate image data for transmission personal computer. In some scanner models, the processor also has interface controller functions.
The list of program instructions for the processor is stored in the persistent memory chip. Data from these microcircuits are recorded by the scanner’s generator at the generation stage. Instead of microcircuits it is called “microprogram” or “firmware”. Some professional scanners have increased the ability to update them, but inexpensive models There is no need to call for home or office.
In addition to permanent memory chips in scanners, random access memory is also used, which plays the role of a buffer (typical values are 1 or 2 MB). Scanned information is submitted here, which is practically immediately transferred to the PC. After loading the memory of the personal computer, the processor resets the buffer to form a new package. Please note that instructions for the processor are also stored in the middle of the RAM, and even in the processor itself (which is equipped with many kilobytes of hard-wired RAM). The organization of memory is inspired by the principle of a conveyor belt. After the following instructions, what to stand through first, a friend sits in this place, and in the remaining place - new instructions.
The scanner's RAM capacity was previously specified in scanner technical specifications. Prote, because This parameter is of little importance to the speed code machine; in modern scanners it is often missed. This is due to the fact that a particular scanner is an area of the computer’s RAM that is implemented by the driver.

Interface controller

The controller communicates to the interface for exchanging information and commands between the scanner and the computer. As I mean above, this microcircuit can be used because the processor is integrated into the controller module. In the era of “two-piece” and “three-piece” scanners were produced with SCSI, IEEE1284 (LPT) and RS-232 interfaces. The current range of SOHO scanners is equipped with USB, FireWire and SCSI interfaces. There have been rumors about the appearance of Bluetooth scanners for some time, but it hasn’t happened yet. It is completely obvious that the same different controllers are installed in devices with different interfaces. The stench among themselves is not crazy, because “they talk in different languages.”

In our version, the interface card connects SCSI and USB ports, as well as
There are two sockets for connecting additional modules

SCSI (Small Computer Systems Interface)

Scanners with a SCSI interface were the most powerful because of this. We need to know when the SCSI scanners are coming (or have already come) to an end. The main reason is the emergence of high-speed USB and FireWire interfaces, which do not require any special care when connecting, nor additional adapters. In the middle of the SCSI interface you can see the throughput capacity, as well as the possibility of connection up to seven various outbuildings one tire. The main disadvantages of SCSI are the high level of organization of the interface and the need to obtain an additional controller.

USB (Universal Serial Bus)

The USB interface has become the most widely used interface for its integration in all current system boards as the main connector for peripheral devices. Today, the absolute majority of home scanners are produced using a USB interface. In addition, a group of CIS scanners eliminates the need for a USB port, which attracts users of portable computers. Wait, you can’t implement this kind of functionality with the help of SCSI.

FireWire (IEEE1394)

When choosing a connection type, note that FireWire interface is shortened. FireWire is the latest high-speed I/O interface that extends from USB so that the connection is secure and does not require the controller. The organization of this work is based on a peer-to-peer scheme. Vlasne for the sake of which I reach the lowest (aligned with USB) respect central processor.
It is easy to use peripheral devices with the new modification of the FireWire 800 (IEEE1394b) interface. This itself will become the most common among peripheral standards, if they were to be fragmented.

Pulling mechanism

The main module of the scanner is the scanning carriage. It includes an optical unit, a system of lenses and mirrors, a light-sensitive matrix, a cold cathode lamp (like a CCD scanner) and an inverter board. Before the sliding carriage there is a long toothed belt, which drives the engine of the device.

Place for fastening the belt to the rolling carriage

Elements of the broaching mechanism

The close contact of the belt with the gears is ensured by a special tension spring, which rests directly on the new one. The carriage with a rolling carriage is moved by guides, along the body of the device (dazzling photo).

Dvigun

Krokovy engine

A small electric motor (Step Motor) can turn the spindle on both sides in very small increments. Thanks to this feature, it is now possible to move the scanner carriage to the original stand. This type of motor is used in a skin flatbed scanner. It wraps the gearbox (the gears you see in the photo) and collapses the carriage in which the optical unit, lamp, and matrix are placed. The choice of direct and winding speed is confirmed by a special microcircuit – the motor controller. The accuracy of the carriage movement is called the mechanical separation of the “Y” (Y-direction).

Optical separation of the scanner - straight X, and yogo
mechanical separate building – straight Y

In general, the optical resolution is determined by the number of elements of the matrix line, divided by the width of the working area. Mechanical – the number of edges of the scanning carriage in the direction of the handle Y. In the specifications for scanners, the sharpness can be specified, such as “600x1200”. Here, another number refers to the mechanical component, just as the first characterizes the optical component of the scanner. The interpolated components are also separated, since the inodes are orders of magnitude larger than the optical value, so as not to be stored in the physical equipment of the device. I would call it “allowed scaling”. Interpolation functions (enhancing the original image) are selected security software scanner. The value of the interpolation values indicated by the publishers is questionable - although the images could be enhanced with the same success using Photoshop.

Engine internals

Gearbox

The engine core from the outer side is connected by a gear transmission, which represents the simplest gearbox. This is a large gear and stretches the belt to which the rolling carriage is secured.

Life block

Scanner life block

Home or office scanners do not require a lot of energy, so there are no powerful elements in the living blocks of SOHO devices. The internal power supply unit of the device, which is shown in this statistic, has voltages of 24 Volts / 0.69 A, 12 Volts / 0.15 A and 5 Volts / 1 A.T. For the dzherel light - cold cathode lamps, a high voltage of several kilovolts is required, for which the food requires a large block, of which I have tested a little more.

Additional devices

For the rich flatbed scanners Additional additives are released, so that in most cases they are bathed in water. These include an automatic document feeder and an adapter for scanning clear originals (slide adapter).

A scanner with an automatic document feeder is bulky.
design

An automatic paper feeder is required in cases where you have to scan other paperless papers. standard format. Make sure you can easily connect an ADF to your scanner. To do this, you can simply look at the connection panel and scroll to the ADF (Automatic Document Feeder) socket. Please note that the automatic document feeder is always “linked” specific model scanner or up to a series of models. There is no universal feeder! The reason lies in the fact that this device controlled from the scanner interface board. It is understood that the feeder operation is not possible without connection with the scanner, so be careful when purchasing and check that your scanner supports the work with a specific autofeeder.

View through the end of the automatic document feeder from another
warehouse side

The automatic feeder uses this method. After the auto-calibration and readiness check stage, the scanner positions the carriage before let's look through the window automatic feeder. Then, sheet-fed originals are picked up from this input tray, and as they pass through the designated window, they are digitized.
The slide adapter is an additional attachment designed for digitizing clear originals (rolls, slides and negatives). There are two types of such adapters: a passive one, which is illuminated by a scanner lamp, and an active transparent one, which is illuminated by a damp lamp.
The active slide adapter is equipped with a light source of light, so that the insightful original shines through. Several models of such slide adapters have a moving carriage with a light shaft, which is driven by a motor and a broaching mechanism. The light rod moves in line with the scanner carriage. The scanner lamp is damaged when it vibrates. Today's latest models of scanners for home and office without loose parts in the slide adapter module. A typical stock - recently tested by our test laboratory EPSON Perfection 3200 Photo. This light source is embedded in the scanner cover and occupies its brown surface. To use the adapter with the scanner, a wire comes out of the cover from the connector, which is connected to a special socket on the rear panel of the device (indicated by the abbreviation XPA). Activation of the adapter lamp is activated automatically when changing the original type in the dryer program, which is additionally indicated by the indicator on the scanner's screen. The originals are inserted into the templates that are included in the kit, which support: a 35 mm stitch with 12 frames, with a 35 mm slide inserted at the frame, 120/220 (6 x 9 cm) / 4 x 5 "". And the templates themselves are placed on the scanner’s slope. During scanning, a stream of light passes through the transparent original and is processed at the input of the optical system of the scanner in a similar way (as the non-transparent original) in the same way. It is clear that the power of the scanner, such as optical separation and light depth, does not change with the use of a slide adapter, which cannot be said about the range of optical thicknesses. This scanner parameter depends on the brightness of the light and the time of exposure. This can be seen this way: the darker the original, the less light it transmits, so it takes longer for the accumulated CCD matrices to collect the required amount of charge. The darkest of the clear originals is X-ray melts (up to 3.6D). To extract a clear scan from them, you will need a bright light source. However, the range of available optical powers of the scanner is in no way determined by the brightness of the lamp. The main priority lies in the capacity (or accuracy) of the analog-to-digital converter, the capacity of the optical system and the flexibility of the light-sensitive matrix.
The passive slide module is simpler and less active. Such an adapter serves as a source of light for the lamp of the scanner itself. The intensity of the light flux in this case is quite lower, lower than with the active adapter. Apparently, the lower density and clarity of scanned images is very suitable, for example, for the Web. Passive slide adapters also come at a low price.

Visnovok

Zagalom, about the scanner, as about the most flexible electronic device It can go on for a long time, but it is impossible to convey all the nuances within one article. Today we explained this: for some reason, CCD scanners digitize originals more clearly, not using devices with a contact sensor; why the discharge capacity of the converter is important and why the optical resolution differs from the mechanical one; how light the dzherela is and how the stench flows onto the brightness of the scan; how the electronic and mechanical parts of the scanner interact, and why slide adapters are not suitable for all devices. By the way, I tried to inform you in the most accessible way possible about the peculiarities of current SOHO scanners, and I would not mind your thoughts about this article.