JP2005184171A - Image reader - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reader quickly increasing a luminous quantity of a light source up to a luminous quantity necessary for reading when a preliminary lighting state is switched into a lighting state. <P>SOLUTION: An image read section includes: a cold-cathode tube; an inverter for applying lighting drive to the cold-cathode tube; a CCD image sensor for reading an original lighted by light from the cold-cathode tube and converting the read image into an electric signal; a thermister for detecting the temperature; and a scanner mechanism control circuit for controlling the inverter on the basis of the temperature detected by the thermister. In the case of preliminary lighting of the cold-cathode tube, whether the temperature detected by the thermister is a low temperature, a medium temperature or a high temperature is determined, an application voltage V1 is selected for the low temperature, an application voltage V2 is selected for the medium temperature, or an application voltage V3 is selected for the high temperature is selected as the lighting application voltage to the cold-cathode tube, and the applied voltage V1, V2 or V3 is used to apply the lighting drive to the cold-cathode tube. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image reading apparatus used in a copying machine, a facsimile machine, a multifunction machine having both a copying function and a facsimile function, for example, using a fluorescent tube or a cold cathode tube as a light source.

  When a fluorescent tube or a cold cathode tube is used as a light source for illuminating a document in the image reading apparatus, there is a problem that it takes time to turn on from a light-off state and reach a sufficient amount of light for reading the document. In order to solve such a problem, one is a method in which the light is always turned on (for example, refer to Patent Document 1), or a method in which the voltage and frequency applied during standby are lowered and the light is kept in the pre-lighted state ( For example, see Patent Document 2).

  In the technology described in Patent Document 1, it is not necessary to provide a waiting time at the start of reading by continuously turning on the cold cathode tube at the time of non-reading other than the standby mode, while in the standby mode, the cold cathode tube is turned off to save power. It is said.

In the technique described in Patent Document 2, for example, once a day, the time of preliminary lighting ON / OFF is automatically determined / updated with reference to the use frequency of the same day of the previous week, or once a day, Referring to the frequency of use on the same day, automatically determine and update the time period for pre-lighting ON with a two-stage duty ratio, or once a day, refer to the frequency of use on the same day last week as the lamp life It automatically determines and updates the pre-lighting ON time zone taking into account the difference in device life.
JP 2002-135536 A Japanese Patent Laid-Open No. 10-336390

  The method of always lighting the fluorescent tube / cold cathode tube is a waste of electric power, and the life of the fluorescent tube / cold cathode tube is shortened. It has become.

  To start reading from the pre-lit state, apply a predetermined voltage and frequency to the fluorescent tube and cold cathode tube to bring the light intensity to the required value, but the time required for this is affected by the environmental temperature, The lower the ambient temperature, the longer it takes. In addition, if the elapsed time is long due to the influence of the elapsed time since the end of the previous reading, the temperature of the fluorescent tube / cold cathode tube tends to decrease, which tends to take time.

  The present invention has been made paying attention to such a problem, and is capable of quickly increasing the light amount of a light source to a light amount necessary for reading when the preliminary lighting state is switched to the lighting state. The purpose is to provide.

  In order to achieve the object, the image reading apparatus according to claim 1 includes a light source, a lighting driving unit that drives the light source to light, and a photoelectric conversion unit that reads a document illuminated by the light from the light source and converts it into an electrical signal. A temperature detection means for detecting the temperature, and a control means for controlling the lighting drive means based on the temperature detected by the temperature detection means, the control means is a lighting drive state at the time of preliminary lighting of the light source Is controlled based on temperature.

  The image reading apparatus according to claim 2 includes a light source, a lighting driving unit that lights and drives the light source, and a photoelectric conversion unit that reads a document illuminated by light from the light source and converts it into an electrical signal. And a control means for controlling the lighting drive means based on the time counted by the time measuring means, and the control means is a lighting drive state when the light source is preliminarily lit. Is controlled based on time.

  An image reading apparatus according to a third aspect of the present invention has the structure according to the first aspect and the structure according to the second aspect, and is illuminated with light from the light source, lighting driving means for lighting the light source, and light from the light source. Detecting with temperature detecting means for detecting temperature, time measuring means for measuring the elapsed time since the last reading of the original, and temperature detecting means, comprising photoelectric conversion means for reading the original and converting it into an electrical signal Control means for controlling the lighting driving means based on the measured temperature and the time counted by the time measuring means, and the control means controls the lighting driving state at the time of preliminary lighting of the light source based on the temperature and time. To do.

  According to the present invention, the lighting driving state (applied voltage or frequency) at the time of preliminary lighting of the light source is controlled based on the (environment) temperature and / or the elapsed time since the end of the previous reading. The brightness of the light source after transition to the state can be quickly increased to the brightness necessary for reading.

  In particular, according to the third aspect of the invention, since the lighting driving state is controlled based on the temperature and the elapsed time, it is possible to more appropriately control the preliminary lighting of the light source according to the environment / usage status of the apparatus.

  Hereinafter, the present invention will be described in more detail with reference to embodiments.

  FIG. 1 is a block diagram showing a configuration example of a facsimile apparatus as an image reading apparatus according to the embodiment. This facsimile apparatus is configured as a multifunction machine having both a facsimile function and a copy function.

  The facsimile apparatus includes a CPU (Central Processing Unit) 1 as a main control unit, an NCU (Network Control Unit) 2, a MODEM 3, a ROM 4, a RAM 5, an image memory 6, and a display unit 7. , An operation panel 8, an image reading unit 9, a printer 10, and a CODEC (Coder and Decoder) 11, which are connected via a bus 13.

  The CPU 1 comprehensively controls each part constituting this apparatus according to a program stored in the ROM 4. The NCU 2 is controlled by the CPU 1 to control connection with the public telephone line network (PSTN) 14 that is a communication line and to send a dial pulse corresponding to the telephone number (including FAX number) of the communication partner. And a function of detecting an incoming call.

  MODEM3 is an ITU (International Telecommunication Union) -T recommendation T.264. 30, T.M. 4 according to the facsimile transmission control procedure (facsimile communication procedure) according to FIG. 17, V. 27ter, V.I. The transmission data is modulated and the received data is demodulated in accordance with 29. The MODEM 3 also has a function of modulating transmission data, which is a digital signal, into an analog voice signal for transmission to the public telephone line network 14 via the NCU 2, and an analog received from the public telephone line network 14 via the NCU 2. The audio signal is demodulated into a digital signal.

  The ROM 4 stores a program for controlling the operation of the entire apparatus. The RAM 5 stores data necessary for control by the CPU 1 and data that needs to be temporarily stored during the control operation. The RAM 5 also has a timer (timer) 5a that measures the elapsed time since the end of reading of the previous document. The image memory 6 encodes the image data read by the image reading unit 9 and stores it in a compressed state. The image memory 6 has a storage area for storing encoded and compressed data and a storage area for storing image data obtained by decoding the image data stored in the storage area.

  The display unit 7 displays icons, key buttons, message contents necessary for data transmission / reception, telephone numbers and FAX numbers input from the operation panel 8, and the like. As the display unit 7, an LCD (Liquid Crystal Display) is used. The operation panel 8 includes a numeric keypad, a mode switching key, a one-touch key, an abbreviated key, a registration key, a start key, a stop key, and the like.

  The image reading unit 9 includes a CCD image sensor (photoelectric conversion unit) 21, an AFE (analog front end) circuit 22, an A / D conversion unit 23, a scanner image processing circuit 24, and a scanner mechanism control circuit (control unit). 25, a thermistor 26 as temperature detecting means, an inverter (lighting drive means) 27, and a cold cathode tube 28 as a light source.

  The CCD image sensor 21 reads an image of one scanning line of an original illuminated with light from the cold cathode tube 28, and sequentially reads the next scanning line image at a predetermined interval. The AFE circuit 22 analog-amplifies the output of the CCD image sensor 21. The A / D converter 23 converts the analog output of the AFE circuit 22 into a digital signal. The scanner image processing circuit 24 performs image processing such as shading correction and gamma correction on the input digital image signal.

  The scanner mechanism control circuit 25 controls a carriage motor (not shown) of the scanner mechanism unit, and also controls a drive voltage applied from the inverter 27 to the cold cathode tube 28 according to the temperature detected by the thermistor 26.

  The printer 10 is of an electrophotographic system, and records received image data and image data of a document read by the image reading unit 9 in a copying operation on a recording sheet. The CODEC 11 encodes (encodes) the read image data by the MH, MR, MMR method, or the like in order to transmit or store the read image data. Also, the CODEC 11 decodes (decodes) the image data received in a compressed and encoded state for recording by the printer.

  The feature of this facsimile apparatus is that the lighting driving state (applied voltage or frequency) at the time of preliminary lighting of the cold cathode tube 28 is controlled based on the (environment) temperature and / or the elapsed time from the end of the previous reading. . As shown in FIG. 2A, the relationship between the environmental temperature and the preliminary lighting application voltage (duty ratio) decreases the applied voltage as the environmental temperature decreases. Further, as shown in FIG. 2B, the relationship between the elapsed time after the end of reading and the preliminary lighting application voltage (duty ratio) increases the applied voltage as the elapsed time increases.

  Next, the point of controlling the lighting driving state during preliminary lighting of the cold cathode tube 28 based on the temperature will be described. Here, as shown in FIG. 3 (a graph showing the relationship between time and lighting applied voltage), an example in which the applied voltage during preliminary lighting is set in three stages based on the detected temperature is taken up. In FIG. 3, the applied voltage is V0> V1> V2> V3.

  During preliminary lighting, the ambient temperature of the apparatus is detected by the thermistor 26, and this detection signal is taken into the scanner mechanism control circuit 25. The scanner mechanism control circuit 25 determines whether the temperature T is T ≦ T1 [environmental state (1)] or T1 <T ≦ T2 with respect to preset temperatures T1 and T2 (T1 <T2). [Environmental state (2)] and T2 <T [Environmental state (3)] is determined.

  If the result of this determination is environmental state (1), the environmental temperature is assumed to be low, and the applied voltage V1 during preliminary lighting is selected. The scanner mechanism control circuit 25 applies the applied voltage V1 to the cold cathode tube 28 by the inverter 27 during preliminary lighting. When the environmental condition (2) is selected, the environmental temperature is assumed to be medium, and the applied voltage V2 during preliminary lighting is selected. When the environmental condition (3) is specified, the environmental temperature is assumed to be high, The applied voltage V3 at the time of lighting is selected, and the applied voltages V2 and V3 are respectively applied to the cold cathode tube 28 by the inverter 27 at the time of preliminary lighting.

  By applying the applied voltages V1, V2, and V3 according to each environmental state (1), (2), and (3) during the preliminary lighting, the light source (cooling) after the transition from the preliminary lighting state to the lighting state is performed. The brightness of the cathode tube 28) can be quickly increased to the brightness required for reading. In the example of FIG. 3, immediately after the transition from the preliminary lighting state to the lighting state, an applied voltage higher than the steady lighting voltage V0 is once applied to the cold cathode tube 28, and then the image is displayed after returning to the steady lighting voltage V0. Reading starts.

  In the example of FIG. 3, it is determined whether the environmental temperature is a low temperature, a medium temperature, or a high temperature based on the detected temperature. However, the environmental temperature may be set to four or more levels, or may be two levels. Alternatively, it may be detected continuously and the applied voltage may be controlled continuously accordingly.

  On the other hand, the point of controlling the lighting driving state during the preliminary lighting of the cold cathode tube 28 based on the elapsed time may be performed in the same manner as in the case of temperature. That is, since the elapsed time from the end of the previous reading of the original is counted by the timer 5a of the RAM 5, the scanner mechanism control circuit 25 sets the elapsed time t to preset times t1, t2 (t1 <t2). On the other hand, whether t ≦ t1 [elapsed state (1)], t1 <t ≦ t2 [elapsed state (2)], or t2 <t [elapsed state (3)] is determined. .

  If the result of this determination is the elapsed state (1), the elapsed time is short. That is, in this case, it is determined that the time has not passed so much since the end of reading of the previous document, and the temperature of the cold cathode tube 28 has not decreased so much. Accordingly, when the elapsed time is short, the applied voltage V3 at the time of preliminary lighting is selected, and the scanner mechanism control circuit 25 applies the applied voltage V3 to the cold cathode tube 28 by the inverter 27 at the time of preliminary lighting. In the elapsed state (2), it is assumed that the elapsed time is medium time, and the applied voltage V2 at the time of preliminary lighting is selected. When it is in the elapsed state (3), it is determined that the elapsed time is long, it is determined that a considerable amount of time has elapsed since the end of reading of the previous document, and the temperature of the cold cathode tube 28 has decreased considerably. The applied voltage V1 at the time of lighting is selected. Then, the applied voltages V2 and V3 are applied to the cold cathode tube 28 by the inverter 27 at the time of preliminary lighting, respectively.

  Also in the control based on the elapsed time, it is determined whether the elapsed state is a short time, a medium time, or a long time based on the elapsed time, but it may be set more finely in four stages or 2 It may be a stage, or may be detected continuously and the applied voltage may be controlled continuously accordingly.

  Further, the voltage applied to the cold cathode tube 28 at the time of preliminary lighting may be controlled based on the temperature and the elapsed time. In this case, it is possible to more appropriately control the preliminary lighting of the light source according to the environment and usage status of the facsimile apparatus.

1 is a block diagram illustrating a configuration example of a facsimile apparatus (a multi-function machine having both a facsimile function and a copy function) according to an embodiment. In the same facsimile machine, a graph (a) showing the relationship between the environmental temperature and the preliminary lighting application voltage (duty ratio), and a graph (b) showing the relationship between the elapsed time after reading and the preliminary lighting application voltage (duty ratio). ). 6 is a graph showing a relationship between a time from preliminary lighting to image reading and a lighting application voltage (duty ratio) to a light source in the facsimile apparatus.

Explanation of symbols

1 CPU
5 RAM
5a Timer (time measuring means)
9 Image reading unit 21 CCD image sensor (photoelectric conversion means)
22 AFE (Analog Front End) Circuit 23 A / D Converter 24 Scanner Image Processing Circuit 25 Scanner Mechanism Control Circuit (Control Unit)
26 Thermistor (temperature detection means)
27 Inverter (lighting drive means)
28 Cold cathode tube (light source)

Claims (3)

In an image reading apparatus comprising a light source, a lighting driving means for lighting the light source, and a photoelectric conversion means for reading a document illuminated with light from the light source and converting it into an electrical signal,
Temperature detecting means for detecting the temperature and control means for controlling the lighting driving means based on the temperature detected by the temperature detecting means, and the control means controls the lighting driving state at the time of preliminary lighting of the light source based on the temperature. An image reading apparatus. In an image reading apparatus comprising a light source, a lighting driving means for lighting the light source, and a photoelectric conversion means for reading a document illuminated with light from the light source and converting it into an electrical signal,
A timing unit that counts the elapsed time from the end of the previous document reading; and a control unit that controls the lighting driving unit based on the time counted by the timing unit. An image reading apparatus that controls a state based on time. In an image reading apparatus comprising a light source, a lighting driving means for lighting the light source, and a photoelectric conversion means for reading a document illuminated with light from the light source and converting it into an electrical signal,
Temperature detection means for detecting the temperature, timing means for measuring the elapsed time since the end of the previous document reading, and the lighting driving means based on the temperature detected by the temperature detection means and the time measured by the timing means An image reading apparatus comprising: a control unit configured to control a lighting driving state during preliminary lighting of the light source based on temperature and time.

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