JP3723432B2 - Image reading apparatus and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image scanner, such as an image scanner connected to a host machine such as a personal computer or an external device such as a printer, a scanner unit of a digital copying machine or a facsimile machine, and an image forming apparatus provided with the image reader. About.
[0002]
[Prior art]
Conventionally, for example, an original image scanned by exposure is optically read by a CCD by moving a manuscript and a light source relatively in the sub-scanning direction by a stepping motor, and the read image data is transferred to an external device via an interface. There is an image reading apparatus configured to do so.
[0003]
In such an image reading apparatus, the document image reading speed is uniquely determined in advance. Further, the transfer speed at which the read image data is transferred to the external apparatus is also fixed depending on the processing speed of the external apparatus.
[0004]
Therefore, when transferring a predetermined number of image data determined by the reading density and the reading area from the image reading apparatus to the external apparatus, the transfer speed for transferring the image data is relatively faster than the reading speed for reading the document. In this case, the image data is transferred to the external device without stagnation in the image reading apparatus. However, if the transfer speed for transferring the image data is relatively slower than the reading speed for reading the original image, the image reading is performed. An image memory such as a DRAM is provided in the apparatus, the image data is temporarily stored in the image memory, and the stored image data is transferred in accordance with the transfer speed of the external apparatus.
[0005]
In general, image data is transferred from an image reading apparatus to an external apparatus by the following processes (1) and (2).
  (1) Store the read image data in an image memory such as a DRAM.
  (2) Transfer image data stored in an image memory such as a DRAM to an external device. The processes (1) and (2) described above are performed simultaneously.
[0006]
Here, when the speed at which the image data is stored in the image memory is relatively faster than the speed at which the image data stored in the image memory is transferred to the external device, the image data gradually accumulates in the image memory. It becomes.
[0007]
On the other hand, since the capacity of the image memory is limited, when a document image is read at a high reading density, a predetermined amount or more of image data is stored in the image memory even if a large-capacity image memory such as a DRAM is used. If it accumulates, stop the stepping motor and interrupt the reading of the original image. When the image data in the image memory decreases to a predetermined amount or less, the original is read again by driving the stepping motor again. This is supported by an intermittent operation in which the image reading process is executed intermittently. In the intermittent operation, a control method for gradually changing the driving speed of the stepping motor called through-up and through-down is adopted for reasons of the nature of the stepping motor.
[0008]
The intermittent operation performed by the image reading apparatus as described above includes a reading mode called a normal intermittent operation in which an original image is read even during execution of through-up and through-down control of the stepping motor, and through-stepping of the stepping motor. There is a reading mode referred to as a return intermittent operation in which reading of a document image is performed only when the stepping motor is at a constant speed without performing reading of the document image during execution of up and through-down control.
[0009]
In the normal intermittent operation, as shown in FIG. 10A, a document image is read at a constant interval in a section where the stepping motor is driven at a constant speed, and a stepping motor is operated in a section where the stepping motor is through-up and down-down. In accordance with the acceleration or deceleration of the document, the document image is read at an interval that is thinner than the reading interval at a constant speed.
[0010]
In the return intermittent operation, as shown in FIG. 10 (b), the original image is not read at all in the through-up and through-down sections of the stepping motor, and the original image is read only in the section where the stepping motor is driven at a constant speed. read. In the return intermittent operation, when reading of the original image is interrupted according to the amount of image data in the image memory, it corresponds to the through-up and down-down sections of the stepping motor so that the reading can be resumed from the position where the reading was interrupted The process of returning the document or the light source by the distance to be performed is performed.
[0011]
Generally, the constant speed of the return intermittent operation is set faster than the constant speed of the normal intermittent operation. For this reason, when reading the same document image, the return intermittent operation can be read faster than the normal intermittent operation.
[0012]
In Japanese Patent Laid-Open No. 5-22531, when reading a document, either one of a preset first speed and a second reading speed higher than the first reading speed is selectively set. An image reading apparatus configured as described above is disclosed. According to the technology disclosed in the publication, it is possible to select a reading speed suitable for high-speed binary reading such as monochrome data and a reading speed suitable for multi-value reading such as a color image. become.
[0013]
[Problems to be solved by the invention]
By the way, when reading a document image by a normal intermittent operation, a return operation such as a return intermittent operation is not necessary in order to always read a document image when the stepping motor is driven, but a stepping motor through-up and through-down control is being executed. However, in order to read the original image satisfactorily without generating jitter, there is a limit to the speed of reading the original image.
[0014]
When reading a document image by a return intermittent operation, in order to read a document image faster than when reading a document image by a normal intermittent operation, it is necessary to increase the reading speed of the document image as much as possible.
[0015]
As a result, when normal intermittent operation and return intermittent operation are performed using a single stepping motor, the performance of the return intermittent operation is reduced when the driving speed of the stepping motor is adjusted to the normal intermittent operation. Therefore, when the return intermittent operation is performed, the quality of the image read in the normal intermittent operation is deteriorated.
[0016]
In addition, when the original image is read by the return intermittent operation, the original image can be read faster than when the original image is read by the normal intermittent operation. However, the constant speed of the stepping motor is set to the constant speed of the normal intermittent operation. By setting a higher speed, the through-up and through-down sections become longer than the through-up and through-down sections in normal intermittent operation. For this reason, when the original image is read by the return intermittent operation in the vicinity of the reading end position of the original image, there is a concern that the apparatus may be damaged due to the traveling body colliding with the wall due to insufficient through-up and through-down sections. .
[0017]
The technique disclosed in Japanese Patent Laid-Open No. 5-22531 can adjust the speed at which the stepping motor is driven, but still has the same problem as described above.
[0018]
An object of the present invention is to obtain an image reading apparatus and an image forming apparatus capable of reading a document image according to a situation.
[0019]
SUMMARY An advantage of some aspects of the invention is that it provides an image reading apparatus and an image forming apparatus capable of selectively using performance priority and conveyance quality priority depending on the situation.
[0020]
An object of the present invention is to obtain an image reading apparatus and an image forming apparatus that can read a document image at an appropriate speed according to the situation.
[0021]
The present invention provides an image reading apparatus and an image forming apparatus that can effectively use the priority of performance and the priority of conveyance quality by utilizing the characteristics of each reading mode by adjusting the reading speed of a document image according to the situation. The object is to obtain a device.
[0022]
An object of the present invention is to provide an image reading apparatus and an image forming apparatus that can prevent the apparatus from being damaged while maintaining the performance of the apparatus.
[0023]
[Means for Solving the Problems]
  An image reading apparatus according to claim 1 is an exposure optical system that exposes a document image, a moving device that relatively moves the exposure optical system and the document image in a sub-scanning direction, and the moving device that performs the operation. A photoelectric conversion element for reading image data of the original image exposed and scanned by relative movement between an exposure optical system and the original image, an image memory for temporarily storing the image data read by the photoelectric conversion element, and the image A transfer means for transferring the image data temporarily stored in the memory to an external device; a speed difference between a speed for storing the image data in the image memory and a speed for transferring the image data to the external device by the transfer means; A speed for managing a relative moving speed of the exposure optical system and the document image by the moving device according to the amount of the image data in the image memory When the moving speed is accelerated or decelerated by the processing means and the speed managing means, the photoelectric conversion element reads out a part of the image data, and the moving speed is determined by the speed managing means. Reading mode setting means for setting any one of the second reading mode in which reading of the image data by the photoelectric conversion element is not performed when is accelerated or decelerated,An interruption determination unit that determines whether reading of the original image by the photoelectric conversion element is interrupted, and an interruption when the reading of the original image by the photoelectric conversion element is interrupted by the interruption determination unit. Interruption position determination means for determining whether the position is closer to the reading start side or reading end side than the predetermined position set within the movable range in the sub-scanning direction, and the interruption position is determined by the interruption position determination means. Is determined to be closer to the end of reading than the predetermined position, the reading mode setting means sets the first reading mode..
[0024]
  Therefore, when the first reading mode is set by the reading mode setting unit in accordance with an arbitrary setting instruction received by the setting receiving unit, the moving speed is accelerated or decelerated by the speed management unit. If the second reading mode is set when the image data is read by the photoelectric conversion element, the image by the photoelectric conversion element is used when the moving speed is accelerated or decelerated by the speed management means. The image data is read only when the data is not read and the moving speed is constant. As a result, the operator can arbitrarily set whether to give priority to performance or conveyance quality according to the situation.
  Further, when it is determined that the reading of the document image is interrupted by the interruption determining unit, and the interruption position determining unit determines that the interruption position is closer to the reading end than the predetermined position set within the movable range in the sub-scanning direction. Is set to the first reading mode. Accordingly, even when priority is given to performance at the time of starting reading, it is possible to switch to transport quality priority according to the interrupted position.
[0025]
According to a second aspect of the present invention, in the image reading apparatus according to the first aspect, the speed management unit adjusts the moving speed according to the first or second reading mode set by the reading mode setting unit. .
[0026]
Therefore, the moving speed is adjusted according to the reading mode by the speed management means. As a result, the image data can be read at a speed suitable for the set reading mode.
[0027]
According to a third aspect of the present invention, in the image reading apparatus according to the first or second aspect, the image reading apparatus further comprises a reading mode determining unit that determines whether or not the second reading mode is set by the reading mode setting unit. When the reading mode determination unit determines that the second reading mode is set, the speed management unit adjusts the moving speed to be faster than the moving speed in the first reading mode.
[0028]
Therefore, when the reading mode determining unit determines that the second reading mode is set, the moving speed when the image data is read by the speed managing unit is higher than the moving speed in the first reading mode. Also adjusted to be faster. As a result, when the first reading mode is set, the image data can be read more reliably, and when the second reading mode is set, the image data can be read more. It becomes possible to increase the speed.
[0029]
According to a fourth aspect of the present invention, in the image reading apparatus according to the first, second, or third aspect, an interruption determination unit that determines whether reading of the document image by the photoelectric conversion element is interrupted, and the interruption determination unit. When it is determined that reading of the original image by the photoelectric conversion element is interrupted, the interruption position is closer to the reading start side or the reading end side than the predetermined position set within the movable range in the sub-scanning direction. Interruption position determination means for determining whether the interruption position determination means determines that the interruption position is closer to the end of reading than the predetermined position, the reading mode setting means changes the first reading mode. Set.
[0030]
Therefore, when it is determined that the reading of the document image has been interrupted by the interruption determination unit, and the interruption position determination unit determines that the interruption position is closer to the reading end than the predetermined position set within the movable range in the sub-scanning direction. Is set to the first reading mode. Accordingly, even when priority is given to performance at the time of starting reading, it is possible to switch to transport quality priority according to the interrupted position.
[0031]
  Claim4The described invention is claimed.1, 2 or 3In the image reading apparatus described above, the transfer unit uses SCSI as an interface between the apparatus and the external apparatus.
[0032]
Therefore, since the general-purpose interface SCSI is used as the data transfer means, it is not necessary to newly develop a dedicated interface.
[0033]
  Claim5In the image reading apparatus according to the present invention, the transfer unit uses IEEE1394 as an interface between the apparatus and the external apparatus.
[0034]
Therefore, since IEEE1394, which is a general-purpose interface, is used as the data transfer means, it is not necessary to newly develop a dedicated interface.
[0035]
  Claim6The image forming apparatus according to the present invention is the first aspect.5The image reading apparatus according to any one of the above is provided, and an image read by the image reading apparatus is formed on a sheet.
[0036]
  Accordingly, claims 1 to5An image read by the image reading apparatus according to any one of the above is formed. This makes it possible to use them according to the situation.
[0037]
DETAILED DESCRIPTION OF THE INVENTION
A first embodiment of the present invention will be described with reference to FIGS. This embodiment is applied to a color image scanner as an image reading apparatus.
[0038]
FIG. 1 is a side sectional view showing a color image scanner according to the first embodiment. The color image scanner 1 includes a scanner body 2 and an ARDF (automatic duplex document feeder) 3 provided on the upper portion of the scanner body 2.
[0039]
On the upper surface of the casing 4 of the scanner body 2, a document glass 5 on which a document is placed when reading a document image in the book mode, and a DF used when reading a document image in the ADF (Automatic Document Feeder) mode. (Document Feeder) glass 6 is provided.
[0040]
Here, the book mode is an operation mode for reading a document image placed on the platen glass 5, and the ADF mode is a mode in which a document is automatically fed by the ARDF 3, and the automatically fed document is read. This is an operation mode in which the original image is read when passing over the DF glass 6.
[0041]
Also, a main body operation panel 7 (see FIG. 2) having a keyboard (not shown) having various keys such as a start key and an abort key and a display (not shown) is provided on the outside of the casing 4. It has been. Further, the keyboard is provided with a mode key as a setting accepting unit that receives a setting instruction for a reading mode in an image reading process described later when pressed down. The mode key includes a normal mode key for setting a normal mode as a first reading mode for executing a normal intermittent operation, and a high speed mode key for setting a high speed mode as a second reading mode for executing a return intermittent operation. Is provided.
[0042]
The casing 4 includes an illumination lamp 8 and a mirror 9, a first traveling body 10 that can travel along the platen glass 5, and mirrors 11 and 12 that can travel along the platen glass 5. A second traveling body 13, a lens 14, and an SBU (Sensor Board Unit) 16 on which a color CCD (Charge Coupled Device) 15 as a photoelectric conversion element is mounted are provided. An exposure optical system 17 is formed by the illumination lamp 8, the mirrors 9, 11 and 12, the first traveling body 10 and the second traveling body 13. The first and second traveling bodies 10 and 13 are driven by a stepping motor 18 as a moving device, and travel at a speed ratio of 2: 1 from the left side to the right side in FIG. Further, inside the casing 4 is provided an SCU (Scanner Control Unit) 19 equipped with an electrical system for controlling the operation of the color image scanner 1 including the scanner body 2 and the ARDF 3. Further, in the casing 4, there are a document size sensor (width) 20 and a document size sensor (length) 21 for detecting the size of the document placed on the document table glass 5 in the document reading in the book mode. Provided (see FIG. 2).
[0043]
The ARDF 3 includes a document table 22 on which a document is placed when the document is read in the ADF mode, a discharge unit 23 that discharges the document that has been read, and a guide that communicates from the document table 22 to the discharge unit 23. A path 24 and a reversing unit 25 for reversing the document in the double-sided reading mode are provided.
[0044]
Here, the double-sided reading mode is an operation mode in which a document is automatically fed by ARDF and an image on the front side is read, and then the image on the back side is read by inverting the document.
[0045]
The document table 22 is provided with document guides 26 for guiding both side edges of the document when the placed document is conveyed to the guide path 24. The document table 22 has a set sensor 27 for detecting whether or not a document is placed on the document table 22 when the document is read in the ADF mode, and a document placed on the document table 22. A width size detection sensor 28 for detecting the size of the document, document length sensors 29 and 30, and a document trailing edge sensor 31 for detecting the trailing edge of the document. In the present embodiment, the set sensor 27, the width size detection sensor 28, the document length sensors 29 and 30, and the document trailing edge sensor 31 are all reflective optical sensors. By these sensors, in the ADF mode, the size of the document placed on the document table 22 is automatically specified even when the size of the document is not specified by pressing the paper designation key or the number key. The
[0046]
On the side of the document table 22 on the guide path 24, a calling roller 32 and a separation roller 33 for separating the documents placed on the document table 22 one by one and feeding them to the guide path 24, A transport unit 39 formed by a paper feed belt 35 wound around a transport roller 34 that transports the document to the paper discharge unit 23, first and second transport rollers 36 and 37, a paper discharge roller 38, and the like is provided. .
[0047]
The reversing unit 25 is provided with a reversing path 40 having one end communicating with a branch point P branching from the middle of the guide path 24 and a reversing table 41 continuously attached to the other end side of the reversing path 40. Yes. The reversing table 41 is provided with a reversing roller 42 that is driven to rotate forward and backward by a paper feed / reversing motor 52a (see FIG. 2). A branching claw 44 that is rotatable about a support shaft 43 as a rotation center is attached to the reversing path 40. The inversion path 40 is opened and closed by the rotation of the branching claw 44.
[0048]
Note that document image reading and document reversing operations in various modes such as a book mode, an ADF mode, and a duplex reading mode are well-known techniques, and thus description thereof is omitted.
[0049]
Next, with reference to FIG. 2, FIG. 3, and FIG. 4, an outline of the electrical connection and operation of each part of the color image scanner 1 will be described. FIG. 2 is a block diagram showing the electrical connection of each part provided in the color image scanner 1 of the first embodiment, FIG. 3 is a block diagram showing a part of the electrical connection in detail, and FIG. 4 is a flow of image data It is a block diagram shown roughly.
[0050]
In the color CCD 15 to which the reflected light from the original is incident, the input reflected light is converted into analog image data of each RGB color having a voltage value corresponding to the intensity of the light.
[0051]
The SBU 16 on which the color CCD 15 is mounted is an analog of each RGB color photoelectrically converted by the color CCD 15 by LSYNC (main scan line synchronization signal) and LGATE (main scan line data output period) output from the RIPU 45 mounted on the SCU 19. The image data is divided into an odd number bit and an even number bit, and sequentially output to a VIOB 47 to which an ADU (ADF Driving Unit) 46 having a function of relaying the power supply of the electrical components used in the ARDF 3 is connected.
[0052]
The VIOB 47 removes the dark potential portion from the input analog image data by the analog processing circuit 48, combines the odd bits and the even bits, and adjusts the gain to a predetermined amplitude, and then performs A / D (Analog / A digital signal is converted by a digital converter 49. Digital image data converted into a digital signal by the A / D converter 49 is output to the SCU 19 via a shading ASIC (Application Specific Integrated Circuit) 50.
[0053]
The digital image data input to the SCU 19 is subjected to shading correction, gamma correction, MTF correction, and the like in the RIPU 45, and then binarized and output together with the page synchronization signal, line synchronization signal, and image clock.
[0054]
Although the description is omitted because it is a known technique, in the shading correction executed in the SCU 19, the density unevenness of the original image is corrected based on the white reference data stored in the line memory 45 a connected to the RIPU 45.
[0055]
By the way, on the SCU 19, a CPU 51 (see FIG. 4) that centrally drives and controls each unit, a ROM (not shown) that stores fixed data in advance, and a RAM (FIG. 4) that stores variable data in a rewritable manner. (Not shown) is implemented. The CPU 51 also performs timing control of the stepping motor 18, the paper feed / reverse motor 52a of the ARDF 3, and the transport motor 52b.
[0056]
Although not particularly illustrated, the main body operation panel 7 is connected to the input port connected to the CPU 51 via the VIOB 47. When each key provided on the keyboard of the main body operation panel 7 is depressed, the CPU 51 detects that the key is depressed via the input port.
[0057]
The digital image data output from the RIPU 45 is input to an OIPU (Option Image Process Unit) 54 connected to the SCU 19.
[0058]
The OIPU 54 performs predetermined image processing on the input digital image data and outputs it again to the SCU 19.
[0059]
Again, the digital image data input to the SCU 19 is input to the video input switching circuit 55. The video input switching circuit 55 is formed so that digital image data from the RIPU 45 is given to the other input, and it is possible to select whether or not to perform image processing by the OIPU 54. Output signals from the video input switching circuit 55 are SIBC (Scanner Image Buffer Controller) 56, 57 or an expansion board that adds a communication function for enabling the color image scanner 1 to be connected to a LAN (Local Area Network). The data is transferred to a host computer (not shown) which is an external device via a certain NIC (Network Interface Card) 58.
[0060]
The SIBC 56 temporarily stores the digital image data output from the video input switching circuit 55 in an image memory (not shown) composed of SDRAM (Synchronous DRAM), and then sequentially stores it in a SCSI (Small Computer System Interface) controller 59. Output.
[0061]
The SCSI controller 59 transfers the image data input from the SIBC 56 to an external device.
[0062]
The SIBC 57 is provided on the IEEE 1394 board, and sequentially outputs the digital image data output from the video input switching circuit 55 to the LINE 60 provided on the IEEE 1394 board. The LINE 60 outputs the input image data to the PIEY 61 provided in the IEEE1394. The PIEY 61 transfers the input image data to an external device. The IEEE 1394 controller 62 is formed by the SIBC 57, the LINE 60, and the PIEY 61.
[0063]
In the color image scanner 1 of the present embodiment, two types of SCSI and IEEE 1394, which are general-purpose interfaces, are freely used as transfer means for transferring image data to the host computer.
[0064]
More specifically, in the document image reading process executed by the CPU 51 under the setting of the book mode, which is the document fixing mode, based on the control program stored in the ROM, the CPU 51 executes the first and second traveling bodies 10. , 13 is driven and controlled via a motor driver, and image data transfer to an external device host computer is controlled via a SCSI controller 59 or an IEEE 1394 controller 62.
[0065]
Next, a data transfer method using SCSI as an interface between the color image scanner 1 and an external device (not shown) such as a personal computer or a printer will be described.
[0066]
The data transfer system on the SCSI is classified into basic asynchronous transfer and synchronous transfer that can be speeded up in classification based on transfer speed.
[0067]
Asynchronous transfer is the basis of the transfer method, and information transfer (for example, message, status) other than data transfer is also transmitted by this transfer method. Specifically, it is based on handshaking by REQ / ACK, and in this transfer mode, transfer of about 1.5 Mbyte / second is possible.
[0068]
On the other hand, synchronous transfer is a mode intended for high-speed data transfer and can be used only in the data phase. In order to use this synchronous transfer mode for data transfer, agreement between the target and the initiator is required. This agreement is made by negotiating two values of “REQ / ACK offset value” and “minimum transfer synchronization” by exchanging messages called Synchronous Data Transfer Request. In this transfer mode, high-speed transfer up to 10 Mbytes / second is possible.
[0069]
Next, a data transfer method and data transfer speed when IEEE1394 is used as an interface between the color image scanner 1 and an external device (not shown) such as a personal computer or a printer will be briefly described.
[0070]
IEEE 1394 is a hardware and software standard for 100 M / 200 M and 400 Mbps data transfer. It has features for plug-and-play and multimedia data transfer, and secures a bandwidth for transferring data such as video and audio, and enables real-time transfer (isochronous data transfer, isochronous data transfer, )have. The data transfer system on IEEE1394 is classified into two types, isochronous transfer and asynchronous transfer.
[0071]
Isochronous transfer has the advantage that the speed of data transfer is guaranteed. Specifically, at least one packet can be sent every 125 μsec per channel, talkers and listeners up to 64 channels per node can be set, and the maximum packet size depending on the data transfer rate of 100M / 200M or 400Mbps Is to be determined.
[0072]
Asynchronous transfer can be performed only after all isochronous transfers have been completed. Isochronous transfers are point-to-point, whereas isochronous transfers have a channel concept and are somewhat similar to broadcasts where talkers and listeners are defined. Each transaction has a transmission-destination and destination ID associated with it.
[0073]
Here, the image reading process will be described with reference to FIGS. FIG. 5 is a flowchart showing an outline of image reading processing in the book mode. The image reading process first waits until it is detected by the operator that the start key is depressed by determining the presence or absence of a signal input to the input port of the CPU 51 via the VIOB 47 (S1).
[0074]
If it is determined in step S1 that the start key has been depressed by determining that a signal has been input to the input port of the CPU 51 (Y in S1), the reading mode is set to the normal mode or to the high speed mode. Is determined (S2).
[0075]
Here, the setting of the reading mode will be described. In the present embodiment, the reading mode corresponding to the mode key depressed by the operator is set until the start of the image reading process is instructed by the operator depressing the start key. Here, the function as the reading mode setting means is executed.
[0076]
In the color image scanner 1 of the present embodiment, the normal mode is set as a default when there is no particular mode key operation before the start key is depressed by the operator.
[0077]
If it is determined in step S2 that the reading mode is set to the normal mode (Y in S2), the first and second traveling bodies 10 and 13 are caused to travel by starting the driving of the stepping motor 18. Then, the original lamp image is exposed and scanned by turning on the illumination lamp 8 (S3).
[0078]
Although detailed description is omitted because it is a known technique, because of the nature of the stepping motor 18, the stepping motor 18 cannot be instantaneously driven at a constant speed. Therefore, in step S3, the number of drive pulses of the stepping motor 18 is set to a predetermined value. Through-up control is gradually increased until the number of pulses becomes. Here, a part of the function as the speed management means is executed.
[0079]
In step S <b> 3, the reflected light from the original image scanned by exposure by turning on the illumination lamp 8 mounted on the traveling first traveling body 10 is photoelectrically converted into analog image data by the color CCD 15. The analog image data is subjected to predetermined processing by the analog processing circuit 48 of the VIO 47B, the A / D converter 49, the shading ASIC (Application Specific Integrated Circuit) 50, the RIPU 45, the OIPU 54, and the video input switching circuit 55 of the SCU 19. The digital image data subjected to image processing is stored in the image memory (S4).
[0080]
The image data storage process in step S4 is performed until it is determined that the amount of image data stored in the image memory has accumulated a predetermined amount or more (hereinafter referred to as “memory near full”) (Y in S5). ) And repeat (N in S5).
[0081]
If it is determined in step S5 that the memory is full (Y in S5), the stepping motor 18 is stopped (S6). The determination of memory near full in step S5 is detected by outputting a memory near full interrupt signal as shown in FIG.
[0082]
Although detailed description is omitted because it is a known technique, the stepping motor 18 cannot be stopped instantaneously due to the nature of the stepping motor 18, and therefore, in step S 6, the number of drive pulses of the stepping motor 18 becomes zero. Until the determination is made (Y in S7), through-down control is performed in which the driving speed of the stepping motor is gradually decreased. Here, a part of the function as the speed management means is executed.
[0083]
If it is determined in step S6 that the number of drive pulses of the stepping motor 18 has become 0 by performing through-down control (Y in S7), the illumination lamp 8 is turned off (S8), and the read image data is transferred. Thus, the process waits until it is determined that the amount of image data in the image memory is equal to or less than a predetermined amount (hereinafter referred to as “memory empty”) that is different from the previously set near full (hereinafter, “memory empty”).
[0084]
The determination of memory empty in step S9 is detected by outputting a memory empty signal (hereinafter referred to as a memory empty interrupt signal) as shown in FIG. 6B.
[0085]
Under the setting of the normal mode, in the section in which the stepping motor 18 is performing through-up or through-down control, the reading interval in the section in which the driving speed of the stepping motor 18 is constant speed is set according to the driving speed of the stepping motor 18 The original image is read at an interval where the frequency is thinned out.
[0086]
FIG. 7 is a flowchart schematically showing the data transfer process. The data transfer process is executed in parallel with the image reading process.
[0087]
In the data transfer process, the presence or absence of digital image data in the image memory is determined, and the process waits until it is determined that there is digital image data in the image memory (S21).
[0088]
If it is determined in step S21 that there is digital image data in the image memory (Y in S21), the digital image data is transferred by the SCSI controller 59 or the IEEE1394 controller 62 (S22).
[0089]
The processing in step S22 is repeated (N in S23) until it is determined that the data amount of the digital image data in the image memory is equal to or less than the specified lower limit (hereinafter, “memory empty”) (Y in S23).
[0090]
If it is determined in step S23 that the memory is empty (Y in S23), a memory empty interrupt signal is output (S24). Based on this memory empty interrupt signal, the determination of memory empty in step S9 in FIG. 5 is executed.
[0091]
Here, returning to FIG. 5 again, if it is determined in step S9 that the memory empty interrupt signal has been interrupted (Y in S9), the process returns to step S3 to drive the stepping motor 18 at a predetermined speed for processing. To continue. Here, the function as the speed management means is executed.
[0092]
Here, when the normal mode is set according to the received arbitrary setting instruction, when the moving speed by the stepping motor 18 is accelerated or decelerated, a part of the image data is thinned out by the CCD. Read.
[0093]
Thus, by arbitrarily setting a process in which the first and second traveling bodies 10 and 13 are stopped when the reading of the document image is completed, the document can be positioned at any position within the movable range in the sub-scanning direction. Even when image reading is interrupted, it is possible to prevent the first and second traveling bodies 10 and 13 from colliding with the casing 4 and being destroyed, thereby improving the conveyance quality.
[0094]
In the present embodiment, each process executed from step S3 to step S9 is a normal intermittent operation (see FIG. 10A).
[0095]
On the other hand, if it is determined in step S2 that the reading mode is set to the high-speed mode (N in S2), it is determined that the number of drive pulses of the stepping motor 18 has reached a preset number of drive pulses. Until this is done (Y in S11), the above-described through-up control is performed (S10).
[0096]
The predetermined number of pulses determined in the high speed mode is larger than the number of pulses set to a constant speed in the normal mode. That is, the constant speed in the high speed mode is set faster than the constant speed in the normal mode.
[0097]
If it is determined in step S11 that the number of drive pulses of the stepping motor 18 has reached a preset number of drive pulses (Y in S11), the illumination lamp 8 is turned on to expose and scan the document image. (S12).
[0098]
In step S12, the reflected light from the document image exposed and scanned by turning on the illumination lamp 8 is subjected to predetermined image processing in the same manner as described above, and is stored in the image memory as digital image data (S13).
[0099]
The image data storage process in step S13 is repeated (N in S14) until it is determined in step S14 that the memory is near (Y in S14).
[0100]
If it is determined in step S14 that the memory is full (Y in S14), the illumination lamp 8 is turned off and the stepping motor 18 is stopped by through-down control (S15).
[0101]
In step S16, if it is determined that the number of drive pulses of the stepping motor 18 has become zero by performing the through-down control in step S15 (Y in S16), the stepping motor 18 is driven in the reverse direction by the through-up control. (S17), the stepping motor 18 is stopped by the through-down control (S18), and the memory empty interrupt signal is output in the state where the first traveling body 13 is retracted from the first stop position. Wait until it is determined to be empty (N in S19).
[0102]
In the present embodiment, the traveling body is moved backward by performing step-up and through-down control of the stepping motor 18, but the present invention is not limited to this, and the stepping motor 18 may be returned at a low speed and a constant speed. By retreating the first traveling body 10, when the reading of the document image is resumed, a sufficient running distance is required to run the first traveling body 10 until the stepping motor 18 reaches a constant speed by through-up control. Is secured. In the present embodiment, the first traveling body 10 is retreated 30 mm from the initial stop position, but the retreat distance is not limited to this.
[0103]
If it is determined in step S19 that the memory is empty by outputting a memory empty interrupt signal (Y in S19), the process returns to step S10 to continue the processing.
[0104]
Here, when the high-speed mode is set according to the received arbitrary setting instruction, the image data is read by the color CCD 15 when the moving speed by the stepping motor 18 is accelerated or decelerated. Instead, image data is read by the color CCD 15 only when the moving speed of the stepping motor 18 is constant.
[0105]
As a result, the high-speed mode can be set arbitrarily according to the convenience of the operator, and reading at high speed can be executed arbitrarily according to the situation.
[0106]
In the present embodiment, each process executed from step S10 to step S19 is a return intermittent operation (see FIG. 10B).
[0107]
As described above, the normal mode and the high-speed mode can be set according to the situation by arbitrarily setting the normal mode and the high-speed mode, and the performance priority and the transport quality priority can be properly used according to the situation. Therefore, the color image scanner 1 that is highly convenient for the operator can be provided.
[0108]
Next, a second embodiment of the present invention will be described. In the second embodiment, the first point is that the original image reading mode to be resumed by detecting the memory empty is automatically set according to the position where the reading of the original image is interrupted by detecting near full. This is different from the embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is also omitted. The same shall apply hereinafter.
[0109]
Although not particularly illustrated, the ROM has a drive pulse number data storage area in which a predetermined drive pulse number of the stepping motor 18 to be referred to in the reading mode automatic setting process described later is stored in advance. The RAM secures a position information storage area in which the number of drive pulses of the stepping motor 18 that has been driven until the reading of the document image is interrupted by detecting near full is temporarily stored.
[0110]
The color image scanner 1 according to the second embodiment determines whether or not reading of a document image has been suspended by detecting near full. Here, a function as interruption determination means is executed.
[0111]
When the reading of the document image is temporarily interrupted, the number of drive pulses obtained by referring to the position information storage area is compared with the predetermined number of drive pulses stored in advance in the ROM drive pulse number data storage area. Thus, it is determined whether the drive pulse number is larger or smaller than the predetermined drive pulse number. Here, the function as the interruption position determination means is executed.
[0112]
If it is determined that the number of drive pulses is smaller than the predetermined number of drive pulses, the reading mode set at the time when the reading is interrupted is maintained when the reading of the document image is resumed by detecting the memory empty. . Here, the function as the reading mode setting means is executed.
[0113]
When it is determined that the number of drive pulses is greater than the predetermined number of drive pulses, when reading of a document image is resumed by detecting memory empty, the reading mode set when reading is interrupted is not affected. Set the normal mode. Here, the function as the reading mode setting means is executed.
[0114]
Here, when it is determined that the stop position is closer to the end side than the predetermined position with respect to the movable range in the sub-scanning direction, the normal mode is set.
[0115]
Thus, regardless of which reading mode is set, the reading mode at the time of resuming reading is automatically set depending on the position where reading of the document image is interrupted. It is possible to prevent breakage due to collision of the casing 13 with the casing 4, and it is possible to maintain conveyance quality even when performance is prioritized.
[0116]
Next, a third embodiment of the present invention will be described with reference to FIG. The third embodiment shows an application example to an electrophotographic copying machine as an image forming apparatus.
[0117]
FIG. 8 is a side view showing a copying machine according to the third embodiment. The copier 63 includes the color image scanner 1 described in the first and second embodiments, and an image forming unit 64 provided below the color image scanner 1.
[0118]
In the image forming unit 64, a sheet conveyance path 69 is formed from a tray 65 for stacking sheets to an electrophotographic image forming unit 66 and a fixing device 67 to the paper discharge stacker unit 68. An image of a document read by the color image scanner 1 and the charger 71 that uniformly charges the surface of the photoconductor 70 is placed on the photoconductor 70 around the photoconductor 70 provided in the approximate center of the image forming unit 66. An exposure device 72 for exposure, a developing device 73 for developing toner by attaching toner to a latent image formed on the surface of the photosensitive member 70 by exposure, and a paper conveyed through a paper conveyance path 69 It is formed by a transfer device 74 for transferring an image.
[0119]
In the copying machine according to the present embodiment, the operation mode of the image forming operation in which the image of the read original is formed on the sheet by the image forming unit 66 in accordance with the reading mode of the color image scanner 1 set by the operator. Is set. Specifically, the image forming operation in each image forming operation mode executed by the image forming unit 64 is the same, but when the normal mode is set for the color image scanner 1, the normal image forming mode is set. If the high-speed mode is set, the high-speed image forming mode is set.
[0120]
In such a configuration, the image of the document read by the color image scanner 1 is formed on the sheet conveyed by the image forming unit 66 with the timing adjusted in the sheet conveyance path 69 and fixed by the fixing unit 67. The
[0121]
As a result, according to the copying machine 63 of the third embodiment, the normal image forming mode and the high-speed image are formed in the image forming operation in which the image of the original read by the color image scanner 1 is formed on the paper by the image forming unit 66. By arbitrarily setting the formation mode according to the operator's convenience, it can be used according to the situation, and performance priority and transport quality priority can be used properly according to the situation. A highly convenient copying machine 63 can be provided.
[0122]
In this embodiment, the electrophotographic image forming unit 66 is used. However, the present invention is not limited to this. For example, the present invention may be applied to an ink jet printer having an ink jet.
[0123]
In this embodiment, an example of application to the copying machine 63 as an image forming apparatus has been described. However, the present invention is not limited to this, and may be applied to, for example, a printer or a facsimile.
[0124]
Next, a fourth embodiment of the present invention will be described with reference to FIG. The fourth embodiment is different from the first or second embodiment in that the driving speed of the stepping motor 18 is adjusted according to the set original image reading mode.
[0125]
Although not particularly illustrated, the ROM has a drive speed data storage area in which data related to the drive speed of the stepping motor 18 referred to in the image data reading process described later is stored in advance. Specifically, the data relating to the driving speed of the stepping motor 18 is set so that the driving speed of the stepping motor 18 in the high speed mode is faster than the driving speed of the stepping motor 18 in the normal mode. In the data relating to the driving speed of the stepping motor 18 in the high speed mode, the number of driving pulses when the first and second traveling bodies 10 and 13 are at a constant speed is stored as a predetermined number of driving pulses.
[0126]
FIG. 9 is a flowchart showing an outline of image data reading processing executed when the operation mode for reading a document is set to the book mode in the color image scanner 1 according to the fourth embodiment. In the reading speed setting process, first, in step T1, it is determined whether or not the start key is depressed. If it is detected that the start key is depressed (Y in T1), whether the reading mode is set to the normal mode or not. It is determined whether the high speed mode is set (T2). Here, the function as the reading mode determination means is executed.
[0127]
If it is determined in step T2 that the reading mode is set to the normal mode (Y of T2), the data related to the driving speed of the stepping motor 18 in the normal mode is obtained by referring to the ROM driving speed data storage area. The driving of the stepping motor 18 is started based on the acquired data and the illumination lamp 8 is turned on (T3).
[0128]
Here, the driving speed of the stepping motor 18 is adjusted according to the set reading mode.
[0129]
As a result, the driving speed of the stepping motor 18 can be set to an optimum value in the normal mode, and it is possible to further improve the conveyance quality and thereby improve the quality of the read image.
[0130]
Thereafter, from step T4 to step T9, processing similar to that from step S4 to step S9 in FIG. 5 is executed.
[0131]
On the other hand, if it is determined in step T2 that the reading mode is set to the high speed mode (N in T2), the driving speed of the stepping motor 18 in the high speed mode is determined with reference to the ROM driving speed data storage area. The above-described through-up control is performed until it is determined that the number of drive pulses of the stepping motor 18 has reached the predetermined number of drive pulses included in the acquired data (T10, T11).
[0132]
Thereafter, from step T12 to step T19, processing similar to that from step S12 to step S19 in FIG. 5 is executed.
[0133]
Here, when the high-speed mode is set, the moving speed when the image data is read is adjusted so as to be faster than the moving speed in the normal mode.
[0134]
As a result, the driving speed of the stepping motor 18 can be set to an optimum value in the high-speed mode, the image reading speed in the high-speed mode can be further increased, and the performance is more effective. Improvements can be made.
[0135]
【The invention's effect】
  According to the image reading apparatus of the first aspect, when the first reading mode is set according to the received arbitrary setting instruction, the moving speed is accelerated or decelerated by the moving device. When the second reading mode is set by reading a part of the image data by the photoelectric conversion element, the image data is read by the photoelectric conversion element when the moving speed is accelerated or decelerated by the moving device. By reading the image data only when the moving speed is constant, the operator can arbitrarily set whether to give priority to performance or conveyance quality according to the situation. Accordingly, it is possible to provide an image reading apparatus capable of reading a document image according to a situation.
In addition, when the interruption position where the reading of the document image is interrupted is on the reading end side from the predetermined position set within the movable range in the sub-scanning direction, the reading is started by setting the first reading mode. Even when priority is given to the performance at the time of the transfer, it is possible to switch to the priority of the transfer quality according to the interrupted position, so that the transfer quality can be maintained even when the priority is given to the performance.
[0136]
According to the invention of claim 2, in the image reading apparatus of claim 1, it is possible to read image data at a speed suitable for the set reading mode by adjusting the moving speed according to the reading mode. Therefore, the original image can be read at an appropriate speed according to the situation.
[0137]
According to a third aspect of the present invention, in the image reading device according to the first or second aspect, when it is determined that the second reading mode is set, the moving speed at the time of reading the image data is set to By adjusting so as to be faster than the moving speed in the first reading mode, it is possible to read the image data more reliably when the first reading mode is set, so that the conveyance quality is improved. In the case where the second reading mode is set, it is possible to speed up the reading of the image data, so that the performance can be given priority more reliably. Thus, by adjusting the reading speed of the original image according to the situation, it is possible to more effectively use the performance priority and the conveyance quality priority by making use of the characteristics of each reading mode.
[0139]
  Claim4According to the described invention, claim 1,2 or 3In the described image reading apparatus, since the general-purpose interface SCSI is used for the data transfer means, the dedicated interface is not newly developed, and the cost is low.2 or 3The described effects can be realized.
[0140]
  Claim5According to the described invention, in the image reading apparatus according to the first, second, third, or fourth aspect, the IEEE1394 which is a general-purpose interface is used as the data transfer means, so that it is possible to reduce the cost without newly developing a dedicated interface. Thus, the effect of the first, second, third or fourth aspect can be realized.
[0141]
  Claim6According to the image forming apparatus of the invention described in the above, by forming an image read by the image reading apparatus according to any one of claims 1 to 6, it is possible to selectively use it according to the situation. An image forming apparatus with high image quality can be provided.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a color image scanner according to a first embodiment.
FIG. 2 is a block diagram illustrating electrical connection of each unit included in the color image scanner according to the first embodiment.
FIG. 3 is a block diagram showing an excerpt of the details.
FIG. 4 is a block diagram schematically showing the flow of image data.
FIG. 5 is a flowchart showing an outline of image data reading processing;
FIG. 6 is a timing chart in image data reading processing.
FIG. 7 is a flowchart schematically showing data transfer processing.
FIG. 8 is a longitudinal sectional view showing a copying machine according to a third embodiment of the present invention.
FIG. 9 is a flowchart showing an outline of image data reading processing according to the fourth embodiment of the present invention;
FIG. 10 is an explanatory diagram for explaining a reading interval of a document image in a normal intermittent operation and a return intermittent operation.
[Explanation of symbols]
1 Image reader
15 Photoelectric conversion element
17 Exposure optical system
18 Mobile device
63 Image forming apparatus

Claims (6)

An exposure optical system for exposing a document image;
A moving device that relatively moves the exposure optical system and the document image in a sub-scanning direction;
A photoelectric conversion element for reading image data of the original image exposed and scanned by relative movement between the exposure optical system and the original image by the moving device;
An image memory for temporarily storing the image data read by the photoelectric conversion element;
Transfer means for transferring the image data temporarily stored in the image memory to an external device;
The exposure by the moving device according to the amount of the image data in the image memory due to the speed difference between the speed at which the image data is stored in the image memory and the speed at which the image data is transferred to the external device by the transfer means. Speed management means for managing the relative movement speed of the optical system and the original image;
When the moving speed is accelerated or decelerated by the speed managing means, the moving speed is accelerated or decelerated by the first reading mode in which the photoelectric conversion element reads out part of the image data and the speed managing means. Reading mode setting means for setting any one of the second reading mode in which the photoelectric conversion element does not read the image data when being performed,
Interruption determination means for determining whether reading of the original image by the photoelectric conversion element is interrupted;
If it is determined by the interruption determination means that reading of the original image by the photoelectric conversion element has been interrupted, whether the interruption position is closer to the reading start side than a predetermined position set within a movable range in the sub-scanning direction is read. An interruption position determination means for determining whether it is on the end side,
2. The image reading apparatus according to claim 1, wherein when the interruption position determination unit determines that the interruption position is closer to the reading end than the predetermined position, the reading mode setting unit sets the first reading mode .   The image reading apparatus according to claim 1, wherein the speed management unit adjusts the moving speed according to the first or second reading mode set by the reading mode setting unit. Reading mode determination means for determining whether or not the second reading mode is set by the reading mode setting means;
When the reading mode determination unit determines that the second reading mode is set, the speed management unit adjusts the moving speed to be faster than the moving speed in the first reading mode. Item 3. The image reading apparatus according to Item 1 or 2. 4. The image reading apparatus according to claim 1 , wherein the transfer means uses SCSI as an interface between the apparatus and the external apparatus. 5. The image reading apparatus according to claim 1, wherein the transfer unit uses IEEE1394 as an interface between the apparatus and the external apparatus. An image forming apparatus comprising the image reading apparatus according to claim 1, wherein an image read by the image reading apparatus is formed on a sheet .

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