JP4298317B2 - Image reading apparatus and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an image reading apparatus that reads an image by scanning a document placed on a document table by moving a carriage, and an image forming apparatus including the image reading apparatus.
[0002]
[Prior art]
  2. Description of the Related Art Image forming apparatuses such as copying machines, facsimile machines, and scanners are provided with an image reading device (scanner) that scans a document placed on a document table and reads a document image. The image reading apparatus includes a light source that illuminates a document and a carriage that moves along a predetermined direction (sub-scanning direction) of the document while supporting a mirror that guides reflected light from the document in a predetermined direction. When scanning a document, the accuracy of the carriage start position is extremely important. Therefore, in the conventional image reading apparatus, a sensor (detection means) for detecting the home position is provided in the vicinity of the home position which is the reference position of the carriage, and the home position is detected by the detection output of this sensor.OutLike to do. This home position search, that is, homing processing (hereinafter referred to as homing processing) is to perform preliminary scanning for copying when the copy button is pressed in the case of a copying machine, or to read an original in the case of a facsimile or scanner. The main scanning is performed immediately before the main scanning. As described above, since the homing operation for positioning the carriage when the power is turned on is controlled so that the scan can be started, the first copy and the first reading time are increased by the homing process. It was customary.
[0003]
On the other hand, in recent years, due to increasing energy saving and environmental problems, there has been a demand for an operation that automatically turns off the power immediately when unnecessary, but on the other hand, a quick start-up after power-on is also required.
[0004]
Therefore, for example, Patent Document 1 proposes that the repeated reading operation is speeded up by causing the carriage displacement correction and homing processing only when the displacement occurs during the carriage return operation. . Further, in Patent Document 2, when the black reference value based on the sensor reading output and the carriage movement distance during the homing process exceeds a preset upper / lower limit value, the previously detected value exceeds the upper / lower limit value. If not, it has been proposed to improve the position accuracy of the read image by using the previously detected value as a reference value for correction, and obtain an image with little variation in position.
[0005]
[Patent Document 1]
JP 2001-356428 A
[0006]
[Patent Document 1]
JP 2002-64683 A
[0007]
[Problems to be solved by the invention]
As in the invention described in the above-mentioned patent document, the present invention also considers that accurate positioning is not necessary if a certain condition is satisfied when the apparatus is activated in advance by a pre-scan start command. The purpose is to obtain a quick rise by omitting the homing operation and starting scanning.
[0008]
[Means for Solving the Problems]
  To achieve the object, the first means includes a light source for illuminating the document and a mirror for guiding reflected light from the document illuminated by the light source, and a carriage movable in the sub-scanning direction with respect to the document. Detecting means for detecting a home position of the carriage; a line sensor for reading an image of the original in the main scanning direction from reflected light from the mirror; and control means for controlling movement of the carriage. In the image reading apparatus, the control means includesWhen the power is turned onWhen the carriage is aligned by performing the homing process, the detection means is in the pre-scan mode.When the power is turned onWhen the carriage is detected, the homingprocessingIt is characterized by not performing.
[0012]
  First2Means1'sAnd an image forming unit that forms a visible image on a recording medium based on image data read by the image reading device.
[0013]
According to the first means, in the case where the apparatus is activated in advance by a pre-scan start command, if a certain condition is satisfied, it is considered that accurate positioning is not necessary, and the homing operation is omitted and the scan starts. Therefore, a quick rise can be obtained.
[0014]
According to the second means, the detection means is arranged so as to be shifted with respect to the carriage movement direction, so that the position detection can be performed with higher accuracy than in the case of a single detection means. The home position can be determined by a limited carriage movement.
[0015]
According to the third means, it is possible to accurately determine whether or not the carriage is in the home position when the power is turned on, and when it is in the normal position, the homing is omitted to shorten the activation time without the activation condition. Can do.
[0016]
According to the fourth means, since the detection means is provided on both end portions in the direction orthogonal to the moving direction of the carriage or on the side surfaces facing the both end portions of the apparatus housing, position detection can be performed with high accuracy.
[0017]
According to the fifth means, since the image reading apparatus operates at a quick rise after the power is turned on, the work can be performed efficiently.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0019]
FIG. 1 is a main part configuration diagram illustrating an image reading apparatus according to a first embodiment of the present invention, FIG. 2 is a diagram illustrating a part of an upper part of an image forming apparatus on which the image reading apparatus is mounted, and FIG. FIG. 4 is a flowchart for explaining the outline of the operation of scan control.
[0020]
The image reading device 50 has a contact glass 6 and a reference white plate (not shown) disposed on the top thereof. The contact glass 6 is for setting an original on the original when reading the original. As shown in FIG. 2, the original is pressed from above so as not to float from the contact glass 6 by a pressure plate 1a which is a pressing plate for the original. Of course, a known document feeder (ADF) may be provided. The reference white plate is a substantially white member having a uniform density provided in the main scanning direction for obtaining correction data for shading correction.
[0021]
  Inside the image reading device 50, a light source 504 such as a xenon lamp that irradiates the reading surface at a certain angle with respect to the surface of the reference white plate or the contact glass 6, and three pieces of light that reflect the light reflected by the reference white plate or the document. First, second and third mirrors 52, 55, 56, a lens block 53 that forms an image of the reflected light from the third mirror 56, a CCD 54 that is a line sensor that converts the reflected light into an analog image signal through the lens 6, and an image signal from the CCD 54 The reading board 507 is provided with various circuits for converting into digital signals. Light source 504 and first mirror 52Is mounted on the first carriage 501, and the second and third mirrors 55 and 56 are mounted on the second carriage 502. The first and second carriages 501 and 502 are connected to the drive motor 50.5Thus, the image of the original is read while moving along the contact glass 6 at a speed of 2: 1.
[0022]
A plurality of document size detection sensors 514 that detect the size of the document are provided at the bottom of the image reading device 50, and a pressure plate open detection sensor 515 that detects opening and closing of the pressure plate 1 a and a home position of the first carriage 501 at the top. There is provided a home position sensor 506 for detecting. In addition to this, although not shown, a peripheral circuit of the drive motor 503 is provided, and reading control is performed at each detection timing.
[0023]
Whether or not the first carriage 501 is located at the home position is detected when the filler 509 provided in the first carriage 501 enters the home position sensor 506, and the sensor 506 is turned on and off when the filler 509 is removed from the sensor 506. Is used.
[0024]
Conventionally, when the image reading device 50 is turned on, the first carriage 501 performs a homing operation, and after adjusting the black level and white level of the reading substrate 507, the image reading device 50 performs the reading operation. Control was in a possible state.
[0025]
Here, in the homing operation, when the home position sensor 506 is on when the power is turned on, the first carriage 501 is once moved in a direction away from the home position sensor 506, and then turned on again after the home position sensor 506 is turned off. The timing to turn it back on is fixed and the position accuracy is improved to be the home position. Further, when the home position sensor 506 is off when the power is turned on, the home position is similarly determined by moving the first carriage 501 in the turning-on direction.
[0026]
In recent years, with the progress of energy-saving technology, when the reading operation is not performed, a method of shutting off the power source of the image reading apparatus is generally used in order to suppress unnecessary power consumption. In this case, when the user wants to use the scanner, the scanning operation cannot be performed unless the initial operation such as the homing process or the adjustment of the reading substrate 507 is waited every time. Conventionally, if the power is kept on, such an initial operation is unnecessary and scanning can be performed immediately, so that the energy saving effect is improved, but the stress is also increased.
[0027]
Therefore, in this first embodiment, the homing operation is omitted if a certain condition is satisfied only when the pre-scan is requested to automatically return from the energy saving mode (power off). Thus, the recovery time is shortened.
[0028]
In a general scanner, a network scanner or the like can be considered as a case of returning from the energy saving mode by using a limited condition of pre-scan as a trigger. That is, this is a case where a command to perform pre-scanning is sent from the network to the image reading apparatus, and then a document is set. Pre-scanning is often used for the purpose of testing whether various settings are correct in advance, so if read data that the user does not like is read, that data is discarded. It is normal. Accordingly, it is considered that registration accuracy is not a problem as long as the image of the document can be confirmed even if there is a slight registration error.
[0029]
Therefore, in the first embodiment, as shown in the flowchart of FIG. 4, when a scan command is received, it is first checked whether or not the command is a pre-scan command (step 101). If the command is not a pre-scan command, homing is performed (step 102), and then the lamp of the light source 4 is turned on.
[0030]
On the other hand, if the command is a pre-scan command and the home position sensor 506 is on, it can be said that the first carriage 501 exists at least near the home position. Is less prone to problems. Therefore, the homing is omitted and the process proceeds to step 103. On the contrary, if the home position sensor 506 is in the off state, the first carriage 501 is considered to be considerably away from the home position, and if the reading is started as it is, the first carriage 501 reads the image. Since homing is indispensable because it may hit the end of the apparatus and break, the process proceeds to step 102 and then proceeds to step 103.
[0031]
After the lamp is lit, adjustments such as black level and white level adjustment of the reading substrate 507 are performed (step 104), and then the image reading device 50 becomes ready for reading operation (step 105), and the scanner operation is started. (Step 106).
[0032]
By performing these controls, the recovery time can be shortened. In addition, it is possible to easily cope with the conventional machine by changing the software, and there is an advantage that it can be reflected even if it is not a newly developed model because there is no need to change the hardware.
[0033]
  In the first embodiment described above, there is one home position sensor. However, in the second embodiment described below, two home position sensors are used. This second embodiment will be described with reference to FIGS. FIG. 5 is a diagram for explaining the positional relationship between the carriage and the home position sensor in the second embodiment, and FIG. 6 is a flowchart showing an outline of the scan control operation in the second embodiment.In addition, although demonstrated as 2nd Embodiment here, this 2nd Embodiment is a reference example of the control using the other sensor types and the sensor in this invention.
[0034]
That is, as shown in FIG. 5, the first and second home position sensors 521 and 522 are arranged at both ends in the direction orthogonal to the moving direction of the first carriage 501 with a slight shift with respect to the moving direction. . This improves detection accuracy and shortens the moving distance of the first carriage 501 during homing, thereby shortening the return time.
[0035]
As described above, in the first embodiment, the position is fixed by turning the first carriage 501 off and on with respect to the home position sensor 506, but the first home position sensor 521 is provided at both ends of the first carriage 501. By arranging the second home position sensor 522 and further shifting its mounting position in a direction orthogonal to the moving direction, it is possible to create a state in which the first home position sensor 521 is on and the second home position sensor 522 is off. it can. When the shift amount of the home position sensor is reduced, the state in which the home position sensors are turned on is pinpointed, and the position accuracy is improved. Therefore, according to the second embodiment, it is possible to obtain a more accurate home position than in the first embodiment.
[0036]
In the homing process, the first carriage 501 is moved in order to turn off the home position sensor 506 in the first embodiment. However, in the second embodiment, only a slight pinpoint state detection is required. Therefore, it is not necessary to turn off the home position sensor and search for the position. As a result, although homing for returning from the energy saving mode is performed, the moving time of the first carriage 501 can be shortened, so that the returning time can be shortened. Further, the present invention is not applicable to the return under the limited condition as in the first embodiment, and can be applied to any return state.
[0037]
In the second embodiment, as shown in the flowchart of FIG. 6, when a scan command is received at the time of return from the energy-saving mode with power shutdown, the state of the home position sensor is detected and the first home position is detected. It is checked whether or not the sensor 521 is turned on (step 201), and then it is checked whether or not the second home position sensor 522 is turned on (step 202). When the first home position sensor 521 is off and when the second home position sensor 522 is off, homing is performed (step 203). On the other hand, when the first home position sensor 521 is on and the second home position sensor 522 is also on, and after performing the homing process in step 203, the lamp of the light source 504 is turned on, the black level of the reading substrate 507, Adjustments such as white level adjustment are performed (step 204), after which the image reading apparatus 50 is ready for reading operation (step 205), and scanner operation is started (step 206).
[0038]
In conventional machines, when shifting to the energy-saving mode, even if the carriage is normally positioned at the home position, the scanner motor cannot be excited while the power is cut off, and the carriage moves due to external vibration or impact. He was homing at the time of return. On the other hand, in the second embodiment, the state of the first and second home position sensors 521 and 522 is detected and the first home position sensor 521 is turned on at the time of return from the energy saving mode with power shutdown. If the second home position sensor 522 is in an off state (pinpoint), it can be determined that the first carriage 501 is in the home position, and the homing operation can be omitted to quickly reach a readable state. In this way, by arranging multiple home position sensors, the position detection accuracy can be improved, so it is easy to determine whether it is necessary to perform homing simply by checking the status of the home position sensor. If there is no, it can be expected to shorten the return time by not performing homing.
[0039]
Hereinafter, an image forming apparatus using the image reading apparatus according to the first and second embodiments will be described.
[0040]
7 is a diagram showing a schematic configuration of an image forming apparatus provided with the image reading apparatus shown in FIG. 1, and FIG. 8 is a block diagram showing a schematic configuration of a control circuit of the image forming apparatus shown in FIG.
[0041]
Hereinafter, the image forming apparatus according to the present embodiment will be described.
When a start key on the operation unit 30 is pressed, a document bundle placed on the document table 2 in the automatic document feeder (hereinafter ADF) 1 is fed from the bottom document. The paper is fed to a predetermined position on the contact glass 6 by the feed roller 3 and the feed belt 4. After the image data of the original on the contact glass 6 is read by the reading unit 50, the original that has been read is discharged by the feeding belt 4 and the discharge roller 5. Further, when it is detected by the document set detection sensor 7 that there is a next document on the document table 2, it is fed onto the contact glass 6 in the same manner as the previous document. The feeding roller 3, the feeding belt 4, and the discharging roller 5 are driven by a conveyance motor 26.
[0042]
The transfer papers stacked on the first tray 8, the second tray 9, and the third tray 10 are fed by the first paper feeding device 11, the second paper feeding device 12, and the third paper feeding device 13, respectively, and are conveyed vertically. The unit 14 is transported to a position where it abuts on the photoreceptor 15. The image data read by the reading unit 50 is written on the photoconductor 15 by the laser from the writing unit 57 and passes through the developing unit 27 to form a toner image. Then, the toner image on the photoconductor 15 is transferred while the transfer paper is conveyed by the conveyance belt 16 at the same speed as the rotation of the photoconductor 15. Thereafter, the image is fixed by the fixing unit 17 and is discharged by the paper discharge unit 18 to the finisher 60 of the post-processing apparatus.
[0043]
The finisher 60 of the post-processing apparatus can guide the transfer paper conveyed by the paper discharge roller 19 of the main body in the direction of the normal paper discharge roller 62 and the direction of the staple processing unit. When the switching plate 61 is switched upward, the paper is discharged to the normal paper discharge tray 64 via the transport roller 63, and when the switching plate 61 is switched downward, the staple table 68 is transported via the transport rollers 65 and 67. Can be conveyed.
[0044]
The transfer paper loaded on the staple table 68 is aligned by the paper jogger 69 every time one sheet is discharged, and is bound by the stapler 66 upon completion of a partial copy. The group of transfer sheets bound by the stapler 66 is stored in the staple completion discharge tray 70 by its own weight.
[0045]
On the other hand, the normal paper discharge tray 64 is a paper discharge tray that can be moved back and forth. The paper discharge tray section 64 that can be moved back and forth has a function of moving back and forth for each original document or each copy section sorted by the image memory and sorting the copy paper that is simply discharged.
[0046]
When forming an image on both sides of the transfer paper, the transfer paper fed from each of the paper feed trays 8 to 10 and imaged is not guided to the paper discharge tray 64 side, and the branch claw 41 for switching the path is provided. By setting it on the upper side, it is once stocked in the duplex feeding unit 111. Thereafter, the transfer paper stocked in the double-sided paper feeding unit 111 is re-fed from the double-sided paper feeding unit 111 to transfer the toner image formed on the photosensitive member 15 again, and the branching claw 41 for switching the path. Is set on the lower side and guided to the paper discharge tray 64. In this way, the duplex feeding unit 111 is used when creating images on both sides of the transfer sheet.
[0047]
The photoreceptor 15, the transport belt 16, the fixing unit 17, the paper discharge unit 18, and the development unit 27 are driven by a main motor 25. Driven by transmission. The vertical conveyance unit 14 is driven to transmit the drive of the main motor 25 by the intermediate clutch 21.
[0048]
FIG. 8 illustrates the control device with the main controller as the center. The main controller 20 controls the entire image forming apparatus. A main motor 25 and various clutches 21 to 24 necessary for paper conveyance and the like are connected to the main controller 20. Further, an image processing unit (IPU) that performs display for an operator, an operation unit 30 that performs function setting input control from the operator, control of a scanner, control for writing a document image into an image memory, control for image formation from an image memory, and the like. 49, a distributed control device such as an automatic document feeder (ADF) 1 is connected. The display is performed via the liquid crystal display 31, and the function setting input from the operator is performed by the key input means 32. Each distributed controller and the main controller 20 exchange machine status and operation commands as necessary. A control program executed by each distributed control device is stored in a ROM inside each distributed control device. An IC card slot 27 is connected to the main controller 20, and control program data stored in an IC card outside the image forming apparatus is downloaded to the ROM inside the distributed control apparatus via the IC card slot 27 for control. It is possible to change the program.
[0049]
With reference to FIG. 7 again, the operation from image reading to image writing in the image forming apparatus will be described.
[0050]
The reading unit 50 includes a contact glass 6 on which an original is placed and an optical scanning system. The optical scanning system includes an exposure lamp 51, a first mirror 52, a lens 53, a CCD image sensor 514, and the like. Yes. The exposure lamp 51 and the first mirror 52 are fixed on a first carriage (not shown), and the second mirror 55 and the third mirror 56 are fixed on a second carriage (not shown). When reading a document image, the first carriage and the second carriage are mechanically scanned as described above at a relative speed of 2: 1 so that the optical path length does not change.
[0051]
This optical scanning system is driven by a scanner drive motor (not shown). The document image is read by the CCD image sensor 54, converted into an electrical signal, and processed. The image magnification is changed by moving the lens 53 and the CCD image sensor 54 in the left-right direction in FIG. That is, the positions of the lens 53 and the CCD image sensor 54 are set in the left-right direction corresponding to the designated magnification.
[0052]
The writing unit 57 includes a laser output unit 58, an imaging lens 59, and a mirror. Inside the laser output unit 58, a rotary polygon mirror (polygon mirror) that rotates at a high speed at a high speed by a laser diode that is a laser light source and a motor. Is equipped.
[0053]
Laser light emitted from the laser output unit 58 is deflected by a polygon mirror that rotates at a constant speed, passes through an imaging lens 59, is folded by the mirror, and is focused on the surface of the photoconductor 15.
[0054]
The polarized laser light is exposed and scanned in the direction (main scanning direction) perpendicular to the direction in which the photosensitive member 15 rotates, and the line-by-line recording of the image signal output from the selector of the image processing unit described later is performed. An image (electrostatic latent image) is formed on the surface of the photosensitive member by repeating main scanning at a predetermined cycle corresponding to the rotational speed and recording density of the photosensitive member 15.
[0055]
As described above, the laser beam output from the writing unit 58 is applied to the photoconductor 15 of the image forming system. Although not shown, a beam sensor for generating a main scanning synchronization signal is disposed at a position where a laser beam near one end of the photoconductor 15 is irradiated.
[0056]
The image forming apparatus shown in FIG. 7 functions as an MFP copier.
[0057]
【The invention's effect】
As described above, according to the image reading apparatus according to the present invention, for example, when starting from a network and performing a pre-scan, the homing process that has been conventionally performed can be omitted, and the startup time can be shortened. In addition, when the power is shut down when not in use, which is required when saving energy, the user's stress during use can be reduced by a simple control change over the conventional machine.
[0058]
In addition, according to the image forming apparatus of the present invention, the image reading apparatus operates with a quick rise after the power is turned on, so that the work can be performed efficiently.
[Brief description of the drawings]
FIG. 1 is a main part configuration diagram illustrating an image reading apparatus according to a first embodiment of the present invention.
2 is a diagram showing a part of an upper part of an image forming apparatus on which the image reading apparatus of FIG. 1 is mounted. FIG.
FIG. 3 is a diagram for explaining a relationship between a carriage and a home position sensor.
FIG. 4 is a flowchart showing an outline of scan control operation in the first embodiment;
FIG. 5 is a diagram illustrating a positional relationship between a carriage and a home position sensor according to a second embodiment of the present invention.
FIG. 6 is a flowchart showing an outline of operation of scan control in the second embodiment.
FIG. 7 is a diagram illustrating a schematic configuration of an image forming apparatus including an image reading apparatus according to the first and second embodiments.
8 is a block diagram showing an outline of a control device of the image forming apparatus shown in FIG.
[Explanation of symbols]
2 Contact glass
3 pressure plate
4 Light source
5a, 5b, 5c first, second and third mirrors
6 Lens block
7 Reading board
7a CCD
50 Image reading device
501 First carriage
502 Second carriage
506, 521, 522 Home position sensor

Claims (2)

A light source that illuminates the document and a mirror that guides reflected light from the document illuminated by the light source, and a carriage that is movable in the sub-scanning direction with respect to the document;
Detecting means for detecting the home position of the carriage;
A line sensor that reads an image of the original in the main scanning direction from the reflected light from the mirror;
Control means for controlling movement of the carriage;
In an image reading apparatus comprising:
Wherein, when performing the positioning of the carriage by performing homing upon power-on, when the mode for prescan, perform the homing process when said detecting means detects the carriage when the power is turned on An image reading apparatus characterized by not having any. An image reading device according to claim 1;
Image forming means for forming a visible image on a recording medium based on image data read by the image reading device;
An image forming apparatus comprising:

Images