JP4315225B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine, a printer, and a facsimile machine that forms an image on a sheet.

Conventionally, when reading an image while moving the image reading apparatus on a car, when the vibration sensor detects excessive vibration during driving on a rough road or the like, the image reading is stopped and the document is fed back. There is known an image reading apparatus that resumes reading after vibration is no longer detected (see, for example, Patent Document 1).
JP-A-11-284801

  In recent years, there has been a large demand for high image quality from users of image forming apparatuses, and image forming apparatuses are also in the direction of outputting high-quality images.

  It is known that such an image forming apparatus that outputs a high-quality image may cause an abnormality in reading a document image even with a minute vibration such as attachment / detachment of a paper feed tray, and the quality may deteriorate. Yes.

  The invention described in Patent Document 1 aims to provide an image reading apparatus that is free from image deterioration even if intense vibration more than expected occurs during traveling in an on-vehicle image reading apparatus. When the vibration sensor detects intense vibration, the image reading is stopped and the original is fed backward, and the reading is resumed after no vibration is detected.

  Therefore, for example, a vibration sensor intended to detect vibrations more than expected while traveling on a rough road may not be able to detect the minute vibrations described above, and an image forming apparatus having such an image reading apparatus outputs as a result. There was a problem that the image quality was lowered.

  In addition, since vibration during traveling includes vibration components in multiple directions, it is necessary to detect vibrations in multiple directions in order to cope with this, but generally, vibrations in multiple directions are detected. The vibration sensor is expensive and increases the cost of the image forming apparatus.

  In view of the above problems, an object of the present invention is to provide an image forming apparatus that is low in cost and does not deteriorate the quality of an output image even when a minute vibration occurs when a paper feed tray is attached or detached.

An image forming apparatus according to the present invention includes an automatic document conveying device that conveys a document, a mounting table on which the document is placed, a reading unit that reads an image of the document, and a storage unit that stores an image read by the reading unit. In the image forming apparatus having a paper feeding unit that feeds paper and a control unit , the paper feeding unit includes a paper tray that stores paper, and a mounting detection sensor that detects that the paper tray is mounted. The control unit includes a first mode in which a document is conveyed by the automatic document conveyance device to read an image of the document, or an image of a document that is stationary and placed on the mounting table. in the second mode scanning and reading a, when executed reading of the document image, attachment and detachment of the sheet tray is detected by the attachment detection sensor before Symbol first mode during execution, the automatic document feeder Document transport by And reading the image of the document by the reading unit, deleting the image data of the document for which reading has been stopped from the storage unit, performing the reading again by feeding the canceled document back to the conveyance start position, When attachment / detachment of the paper tray is detected by the attachment detection sensor during execution of the second mode, scanning of the scanning unit of the reading unit and reading of an image of the document by the reading unit are stopped, and reading is stopped. The image data of the original is deleted from the storage unit, the scanning unit of the reading unit is moved to the home position, and then the reading is performed again. The control unit detects whether the mounting detection sensor is attached or detached. In some cases, during execution of the first mode, the document that has been fed back to the conveyance start position is immediately re-conveyed to read the image of the document, Serial in the second mode during execution, an image forming apparatus characterized by reading an image of a document by the reading unit immediately resumes scanning of the scanning unit is moved to the home position.

  In the present invention, the attachment detection sensor for detecting attachment / detachment of the paper feed tray detects the attachment / detachment of the paper feed tray, thereby stopping the reading of the original, performing the re-reading, and forming an image based on the re-read original image. To do. As a result, it is possible to estimate the occurrence of minute vibration at a low cost without providing a new sensor, and an image that does not deteriorate the quality of the output image even if minute vibration occurs when the paper feed tray is attached or detached. A forming apparatus can be provided.

  The best mode for carrying out the present invention will be described below with reference to the drawings. In addition, the structure of this invention is not limited to the following embodiment, It can change suitably in the technical scope of this invention.

  The main vibrations generated by the image forming device are vibrations when the paper feed tray is attached / detached and vibrations when the maintenance door is opened / closed. explain.

  FIG. 1 is a schematic sectional view of the image forming apparatus.

  As an image forming apparatus, a tandem type full-color copying machine will be described as an example.

  The image forming apparatus 1 includes an automatic document feeder 20, a reading unit 10, an image forming unit 30, a paper feeding unit 40, a fixing device 50, and a paper discharge tray 60 on which fixed paper is stacked.

  The image forming apparatus 1 has, as reading modes, a first mode in which the automatic document feeder 20 transports the document D to the reading region R and reads the document D placed on the platen glass 4 without automatically transporting the document D. Has a second mode.

  Examples of the paper used in the image forming apparatus include paper and an OHP sheet.

  The reading unit 10 is disposed above the image forming unit 30 that performs image formation. By irradiating light from the reading unit 10, an image of the document D is formed on the line image sensor CCD and read.

  The automatic document feeder 20 is installed on the upper portion of the reading unit 10, and in the first mode, the image of the document D conveyed by the automatic document feeder 20 is irradiated with light while the scanning unit of the reading unit 10 is stationary. As a result, the image of the document D is formed on the line image sensor CCD and read.

  In the second mode in which the automatic document feeder 20 is not used, the image of the stationary document placed on the platen glass 4 by the operator scans the scanning unit of the reading unit 10 to scan the line image sensor. The image is formed on the CCD and read.

  An analog signal of the original image photoelectrically converted by the line image sensor CCD is subjected to analog processing, A / D conversion, shading correction, image compression processing, etc. in an image processing unit (not shown), and Y (yellow), M (magenta) ), C (cyan), and K (black) digital image data.

  An image forming unit 30 that forms an image using an electrophotographic process includes a photoreceptor 1Y, 1M, 1C, 1K, a charging device 2Y, 2M, 2C, 2K, an exposure device 3Y, 3M, 3C, 3K, a toner replenishing device 4Y, 4M, 4C, 4K, developing devices 5Y, 5M, 5C, 5K, primary transfer rollers 6Y, 6M, 6C, 6K, cleaning units 7Y, 7M, 7C, 7K, intermediate transfer body 70, rollers 71, 72, 73, 74, a secondary transfer roller 75, and a cleaning unit 77.

  The drum-shaped photoreceptors 1Y, 1M, 1C, and 1K corresponding to the colors Y, M, C, and K are uniformly charged by the charging devices 2Y, 2M, 2C, and 2K corresponding to the colors.

  The exposure devices 3Y, 3M, 3C, and 3K corresponding to the respective colors form latent images on the corresponding photoreceptors 1Y, 1M, 1C, and 1K based on the digital image data of the respective colors.

  Each color toner is supplied to the developing devices 5Y, 5M, 5C, and 5K from the toner replenishing devices 4Y, 4M, 4C, and 4K for supplying the toner. The latent images corresponding to the colors formed on 1C and 1K are visualized.

  The developing devices 5Y, 5M, 5C, and 5K and the photoconductors 1Y, 1M, 1C, and 1K are arranged in a vertical column, and rollers 71 and 72 are disposed on the left side of the photoconductors 1Y, 1M, 1C, and 1K in the drawing. , 73, 74 are arranged in a semiconductive endless belt-like intermediate transfer body 70 that is rotatably supported.

  The intermediate transfer member 70 is driven in the direction of the arrow by a motor connected to the drive roller 71.

  The primary transfer rollers 6Y, 6M, 6C, and 6K corresponding to each color are selectively operated according to the type of image by the control unit, and the intermediate transfer body 70 is applied to the corresponding photoreceptors 1Y, 1M, 1C, and 1K, respectively. Press.

  Thus, the toner images of the respective colors formed on the photoreceptors 1Y, 1M, 1C, and 1K by the developing devices 5Y, 5M, 5C, and 5K are transferred to the intermediate transfer member by the primary transfer rollers 6Y, 6M, 6C, and 6K. A primary toner image is sequentially transferred onto the toner image 70 to form a superimposed color toner image.

  After the toner image is transferred to the intermediate transfer member 70 by the primary transfer rollers 6Y, 6M, 6C, and 6K, the residual toner is removed from the photosensitive members 1Y, 1M, 1C, and 1K by the cleaning units 7Y, 7M, 7C, and 7K. The

  The paper feed unit 40 includes a first paper feed tray 401, a second paper feed tray 402, and a third paper feed tray 403, and paper P is stored in each paper feed tray.

  The paper P is fed by the paper feed unit 41, passes through a plurality of intermediate rollers 405, 406, 407, 408, etc. and a registration roller 409, and is conveyed to the secondary transfer region 751, and is transferred onto the intermediate transfer member by the secondary transfer roller 75. The color toner images are secondarily transferred onto the paper P at once.

  The paper feed unit 40 includes first, second, and third attachment detection sensors S1, S2, and S3 that detect that the first, second, and third paper feed trays 401 are attached to the image forming apparatus. The control unit 80 constantly monitors the ON / OFF signal of the mounting detection sensor of each tray.

  The first, second, and third paper feed trays are attached and detached in the front and back directions in the figure.

  The attachment detection sensors S1, S2, and S3 are provided on the back side in the attachment / detachment direction of the paper feed tray as indicated by the broken lines in the figure, and detect the paper feed tray when the paper feed tray is attached on the back side. An ON signal is output.

  The secondary transfer roller 75 is brought into pressure contact with the roller 72 via the intermediate transfer body 70 only when the sheet P passes and secondary transfer is performed.

  The sheet on which the color toner image has been transferred is subjected to fixing processing by a fixing device 50 having a heating roller 51 incorporating a heater H and a pressure roller 52, sandwiched between discharge rollers 76, and discharged from a discharge port 78 to a discharge tray 60. The paper is discharged and collected.

  After the color toner image is transferred onto the paper by the secondary transfer roller 75, the residual toner is removed by the cleaning unit 77 from the intermediate transfer body 70.

  The operation panel 90 is disposed on the upper surface of the reading unit 10 and includes a touch panel and various operation switches. The operation panel 90 displays various information and various operation keys on the touch panel, and switch and key input information is input to the control unit 80. .

  The automatic document feeder 20 and the reading unit 10 will be described in detail below.

  The automatic document feeder 20 separates the stacked documents D one by one, conveys them to the reading region R, and then ejects them onto the paper ejection tray 33.

  The document tray 21 has a regulating member 211, and the regulating member 211 regulates and aligns the end portions of the document in the direction orthogonal to the feeding direction of the document D.

  The pair of feed rollers 22 that can be moved up and down is connected to a drive source (not shown), and feeds the uppermost document of the documents D stacked on the document tray 11.

  The separation / feed roller pair 23 arranged on the downstream side of the feed roller pair 22 includes a feed roller connected to a driving source and a separation roller having a torque limiter.

  The registration roller pair 24 arranged further downstream of the separation feeding roller pair 23 is a document conveyance start position, and adjusts the timing of feeding the document D to the reading region R.

  For example, a stepping motor can be used as a drive source for the feed roller pair 22, the separation feed roller pair 23, and the registration roller pair 24.

  The document D fed from the registration roller pair 24 serving as the transport start position is transported in the direction of the arrow along the guide plate 25, and is sandwiched between the rotating large-diameter transport drum 26 and the driven rollers 261 and 262. Guided by the guide 27, transported along the outer peripheral surface of the transport drum 26 and reaches the reading region R.

  When the document D passes through the reading region R where the slit glass 100 made of a transparent member such as glass and the conveying drum 26 face each other, the image on the surface of the document is read by the reading unit 10.

  After the document D that has passed the reading region R is conveyed upward in the drawing, in the case of single-sided reading, it is guided by the switching guide member 31 and discharged onto the discharge tray 33 by the discharge roller 32.

  In the case of double-sided reading, the conveyance direction is reversed by the reverse conveyance roller 29, conveyed again to the conveyance drum 26 by the switching guide member 31, conveyed to the reading region R, and the back surface is read.

  Then, after being conveyed to the reverse conveying roller 29, it is guided by the switching guide member 31 and discharged onto the discharge tray 33 by the discharge roller 32.

  The reading unit 10 reads an image of the document D conveyed by the automatic document conveying device 20 or an image of the document D placed on the platen glass 4.

  The reading unit 10 includes a scanning unit 11 that is configured integrally with a light source 101, a first mirror 102, and second and third mirrors 104 and 105.

  The light source 101 is a xenon lamp or a fluorescent lamp. The first to third mirrors 102, 104, and 105 are rectangular mirrors that are long in the main scanning direction. The light source 101 and the first to third mirrors 102, 104, and 105 are arranged in parallel.

In the first mode, the scanning unit 11 is stationary and the image of the document D conveyed through the reading region R by the automatic document feeder 20 is read. The light source 101 illuminates the document D conveyed in the reading region R, and the reflected light L of the image of the document D is a line image sensor via the first, second, and third mirrors 102, 104, 105 and the imaging lens 106. An image is formed on the CCD.
The position of the scanning unit 11 where the light source 101 irradiates the reading region R and forms an original image on the line image sensor CCD is defined as a home position.

  In the second mode, when scanning the scanning unit 11 and reading the image of the document D placed on the platen glass 4, the scanning unit 11 moves from the home position in the sub-scanning direction (right direction indicated by a broken line in the drawing). Scan and read the original image during scanning.

  FIG. 2 is an explanatory diagram of a tray mounting detection sensor.

  2A shows a state where the paper feed tray is mounted in the image forming apparatus, and FIG. 2B shows a state where the paper feed tray is detached from the image forming apparatus.

  The term “mounted” refers to a state where the paper feed tray is set at a position where paper can be fed in the image forming apparatus.

  Insertion refers to a process in which a paper feed tray is mounted in the image forming apparatus, and mounting refers to a point in time when the state changes from a detachable state to a mounted state by insertion.

  “Removal” refers to a process in which the paper feed tray is detached from the image forming apparatus, and “removal” refers to a point in time when the mounted tray changes from a mounted state to a detached state.

  Since the mounting detection sensors S1 to S3 that detect that the paper feed trays 401 to 403 are mounted in the image forming apparatus have the same structure and operation, the first mounting detection sensor S1 is taken as an example. I will explain.

  The first attachment detection sensor S1 is a positive first detection member S11 that comes into contact with a contact portion 4011 provided on the first paper feed tray 401 when the first paper feed tray 401 is attached to the image forming apparatus. And a second detection member S12 on the ground side.

  The other end of the first detection member S11 is connected to the control unit 80 via a resistor PO, and the connection point between the first detection member S11 and the resistor PO is connected to the anode side of the power source via the resistor RP (even if it is a cathode depending on the circuit configuration). Good) connected and pulled up.

  The second detection member S12 is connected to the 0V side of the power source.

  The first detection member S11, the second detection member S12, and the contact portion 4011 are made of a conductive material.

  The first detection member S11 and the second detection member S12 are short-circuited by the contact portion 4011 while the first paper feed tray 401 is mounted in the image forming apparatus (FIG. 2A).

Thus the output voltage S1 _OUT of the first detection member S11 is at the L level.

  Further, the first detection member S11 and the second detection member S12 are not short-circuited by the contact portion 4011 while the first paper feed tray 401 is not mounted in the image forming apparatus (FIG. 2B).

Thus the output voltage S1 _OUT of the first detection member S11 is at the H level.

Therefore, at the time of mounting to the image forming apparatus 1 of the first paper feed tray 401 output voltage S1 _OUT changes from H level to L level. Further, by the time of desorption output voltage S1 _OUT is changed from L level to H level, it is possible to detect the occasion of mounting and detaching of the paper feed tray.

  If a similar detection member is provided as a detection member for detecting the opening / closing of the maintenance door, vibration related to the opening / closing of the door can also be detected.

  FIG. 3 is an explanatory diagram showing the relationship between the output of the attachment detection sensor and the reading of the document image.

  The horizontal axis shows the passage of time, and the time has passed from the left to the right in the figure.

  FIG. 3A shows the removal of the paper feed tray, and FIG. 3B shows the insertion of the paper feed tray.

In FIG. 3A, A indicates the time when the paper feed tray is detached, that is, the time when the output voltage S1 _OUT described in FIG. 2 changes from the L level to the H level.

  B indicates a take-out period required for the take-out operation of the paper feed tray.

  When the paper feed tray is removed / attached A, the conveyance and reading of the original are stopped. After the conveyance of the original is stopped, the image data of the original whose conveyance is canceled is deleted from the storage unit, and the original whose conveyance is stopped is sent back to the conveyance start position.

  After elapse of a predetermined time t1 from the time A when the paper feed tray is attached / detached, the original is conveyed again and the original image is read again.

  Note that the predetermined time t1 is set to a time t1 'required for normal extraction plus a margin time α in order not to start reading the original image until the extraction operation is completed.

In FIG. 3B, C indicates when the paper feed tray is mounted, that is, when the output voltage S1 _OUT described in FIG. 2 changes from the H level to the L level.

  When the paper feed tray is installed, the conveyance of the original and the reading of the original image are stopped. Immediately after the conveyance of the original is stopped, the image data of the original whose reading is stopped is deleted from the storage unit, and the original whose conveyance has been stopped is deleted. The document is fed back to the conveyance start position, and then the document conveyed to the conveyance start position is re-conveyed, and the re-conveyed document image is read again. When the attachment of the paper feed tray is detected, there is no subsequent operation as in the case of attachment / detachment, and there is no problem even if the re-reading is started immediately without waiting for a predetermined time.

  D indicates an insertion period necessary for the operation of inserting the paper feed tray.

  Here, since the insertion operation is surely completed at the time of mounting C, it is possible to read the original image from when the paper feed tray is mounted. May not have been done correctly.

  For this reason, it is preferable to delete the image data of the original read within the predetermined time t2 not only when the paper feed tray is attached but before the time C when the paper feed tray is attached from the storage unit and perform rereading.

  In order to reliably exclude the original image read while the insertion operation is being performed, it is preferable to set the predetermined time t2 as a time obtained by adding the margin time β to the time t2 ′ required for the insertion operation. .

  When reading a document image on a platen glass without using an automatic document feeder, it is not necessary to transport the document, reversely transport the document to the transport start position, and re-transport the document in FIGS. It becomes.

  As described above with reference to FIG. 2 and FIG. 3, the detection at the time of attachment / detachment of the paper feed tray that generates minute vibration compared to the intense vibration more than expected during traveling that the image forming apparatus mounted on the vehicle receives, By detecting with an existing tray detection sensor having an extremely simple structure, an increase in the price of the image forming apparatus can be suppressed.

  FIG. 4 is a block diagram relating to the control of the reading unit 10 and the automatic document feeder 20 when the paper feed tray is attached / detached.

  Hereinafter, with reference to FIGS. 1 and 4, a configuration related to the control of the reading unit 10 and the automatic document feeder 20 when the paper feed tray is attached / detached when the automatic document feeder 20 is used for reading will be described.

  The control unit 80 includes a CPU (Central Processing Unit) 801, a RAM 802 (Random Access Memory), a ROM (Read Only Memory) 803, an HDD (Hard Disk Drive) 804, and various members. Are provided under the control of the CPU 801, and an I / O controller 805 and a bus 806 for interconnecting them.

  The ROM 803 stores in advance a program for controlling the entire image forming apparatus, a program for controlling the reading unit 10 and the automatic document feeder 20 when the paper feed tray is attached and detached, which will be described later, and the CPU 801 stores these programs. The program is successively expanded in the RAM 802 and executed.

  The HDD 804 serving as a storage unit temporarily stores digital image data subjected to image processing such as image compression. Note that digital image data or the like may be temporarily stored in the RAM 802 as a storage unit.

  Under the control of the CPU 801, the operation panel 90 displays various operation screens and reading mode switching keys for the reading unit via the I / O controller 805, and operation information selected on the operation screen (input of various keys). Information) is input to the control unit 80.

  When the start key of the image forming apparatus is input from the operation panel 9, the automatic document feeder 20 is controlled by the CPU 801 through the I / O controller 805 and the pair of feeding rollers 22, the separation feeding roller pair 23, and the registration. The roller pair 24, the conveyance drum 26, and the like are operated to convey the document D to the reading area, and then eject it to the sheet ejection tray 33.

  The automatic document feeder 20 and the image forming apparatus main body are provided with a connector (not shown) to which signal lines are connected, and the image forming apparatus main body and the automatic document feeder 20 are controlled via the connector. Send and receive information.

  The reading unit 10 is located at the above-described home position, reads an image from a document conveyed by the automatic document conveying device 20 via the I / O controller 805 under the control of the CPU 801, and sends analog image data to the control unit 80. input.

  The control unit 80 digitizes the analog image data and stores it in the HDD 804.

  The first, second, and third attachment detection sensors S1 detect that the first, second, and third paper feed trays 401, 402, and 403 are attached to the image forming apparatus, and control the CPU 801. Then, a tray mounting signal is input to the control unit 80 via the I / O controller 805.

  The paper feed unit 40 is controlled by the CPU 801 based on the paper feed tray information input from the operation panel 9 via the I / O controller 805, and the first, second, and third paper feed trays 401, 402, Paper is fed from a predetermined paper feed tray 403.

  Further, the image forming unit forms a latent image on the photosensitive member by the laser diode of the exposure unit based on the image data read from the HDD via the I / O controller 805 under the control of the CPU 801 and develops it. A toner image is formed by the unit.

  Then, the toner image is transferred and fixed on the sheet fed from the sheet feeding unit 5.

  Under the control of the CPU 801, the paper conveyance unit positions the paper P supplied from the paper supply unit 5 via the I / O controller 805 by the registration roller 46 and conveys the paper P toward the transfer position 351 at a predetermined timing. .

  The fixing unit 50 adjusts the temperature of the heating roller 71 via the I / O controller 805 under the control of the CPU 801 to fix the toner image.

  Under the control of the CPU 801, the re-feeding unit performs reversal and re-feeding of the paper at the paper reversing unit during double-sided printing or the like via the I / O controller 805.

  FIG. 5 is a flowchart relating to the control of the reading unit 10 and the automatic document feeder 20 when the paper feed tray is attached / detached in the image forming apparatus.

  Hereinafter, the control of the reading unit 10 and the automatic document feeder 20 when the paper feed tray 401, 402, or 403 is attached or detached will be described with reference to FIGS.

  When the start key of the operation panel 90 is input by the operator (S01), image formation control is started (S02). First, the control unit 80 determines whether or not the reading mode is the first reading mode (S03). If it is in the first reading mode (S03: Yes), the automatic document feeder 20 is controlled to start conveying the document (step S04). In the document transport device 20, the feed roller pair 22, the separation feed roller pair 23, the registration roller pair 24, the transport drum 26, and the like rotate normally, and the document is transported to the reading region R.

  The control unit 80 starts reading the image of the document conveyed to the reading region R by the reading unit 10 (S06).

  On the other hand, if it is not the first reading mode (S03: No), that is, if it is the second reading mode, scanning of the scanning unit is started (S05), and the process proceeds to step S06 as described above.

The control unit 80 performs analog processing, A / D conversion, shading correction, image compression processing, and the like on the image data of the document read by the reading unit 10, and performs Y (yellow), M (magenta), C (cyan), K (black) digital image data for each color is used, and storage in the storage unit such as the HDD 804 is started (S07).

  Next, it is determined whether or not the reading of the document by the reading unit 10 is completed (S08).

  If the controller 80 determines that the reading of the document has not been completed (S08: No), that is, if reading is in progress, the process proceeds to the next step S09.

  In step S09, the control unit 80 monitors changes in the output voltages of the mounting detection sensors S1, S2, and S3, and determines whether or not the paper feed tray has been attached or detached (S09).

  The output voltage of the mounting detection sensor is monitored at intervals of 5 to 50 msec, preferably at intervals of 10 msec.

  If it is longer than this, if the paper feed tray is attached or detached immediately before the end of image reading, there is a possibility that the detection is not performed and the image quality is deteriorated. On the other hand, if it is short, the CPU is loaded and there is a possibility of hindering the entire processing.

In many cases, the paper feed tray that is being fed is locked to prevent the paper tray from being attached or detached. Repeat for paper trays other than trays.
If attachment / detachment is not detected (S09: N0), the process returns to step S08, and the determination is repeated until the reading of the document is completed.
When the attachment / detachment is detected (S09: N0), the control unit 80 stops reading by the reading unit 10 (S10), and further erases the image data of the page being read stored in the storage unit (S11).

  Next, the control unit 80 determines whether or not the reading mode is the first reading mode (S12). When the reading mode is the first reading mode (S12: Yes), the control unit 80 stops the conveyance of the original and sends the original being read back to the conveyance start position (S13).

  On the other hand, when the reading mode is not the first reading mode (S12: No), that is, when the reading mode is the second reading mode, the control unit 80 stops scanning of the scanning unit and moves the scanning unit to the home position (S14). .

  Then, in step S09, the control unit 80 determines whether the attachment / detachment when the attachment / detachment of the sheet feeding tray is detected is attachment / detachment (S15). Here, the control unit 80 determines that the time when the paper feed tray is attached from when the H level changes to the L level, and the time when the paper feed tray is detached when the paper level changes from the L level to the H level.

  When it is determined that the attachment / detachment is detachment (S15: Yes), the control unit 80 determines whether or not a predetermined time has passed (S16). When the predetermined time has passed (S15: Yes), the control unit 80 proceeds to step S03. Shift to read again. If the predetermined time has not elapsed (S15: No), the determination in step S16 is repeated.

  On the other hand, if it is determined that the attachment / detachment is not attachment / detachment (S15: No), that is, if the attachment is attachment, the control unit 80 proceeds to step S03 and performs reading again.

If it is determined in step S08 that the reading of the original has been completed (S08: Yes), the controller 80 determines whether there is a next original (S17). If there is a next original (S17: Yes), the control unit 80 returns to step S03 and continues the same flow.
On the other hand, if there is no next original (S17: No), the control unit 80 ends the flow (END).

  As described above with reference to FIGS. 1, 4, and 5, the attachment / detachment of the paper feed tray is detected in the image forming apparatus having the reading unit and the automatic document feeder and executing the first mode. In this case, after stopping the paper conveyance of the automatic document conveyance device by the detection and the reading of the original by the reading unit, by re-conveying and re-reading the original of the conveyance stopped, when the paper feeding tray is attached or detached, etc. Therefore, it is possible to provide an image forming apparatus that does not deteriorate the output image quality even if there is minute vibration.

  Further, in the image forming apparatus that does not have the automatic document feeder but has the reading unit and the scanning unit and executes the second mode, when the attachment / detachment of the paper feed tray is detected, the detection of the reading unit is detected. After stopping scanning and reading of the scanning unit, the scanning unit is scanned again to read the original that has been stopped. Therefore, it is possible to provide an image forming apparatus that does not reduce the image quality.

  In addition, a maintenance door open / close detection member is provided to detect the opening / closing of the door and perform the same processing as when the attachment / detachment of the paper feed tray is detected. Needless to say, it is possible to provide an image forming apparatus that does not deteriorate image quality.

1 is a schematic sectional view of an image forming apparatus. It is explanatory drawing of a mounting | wearing detection sensor. It is explanatory drawing which shows the relationship between the output of a mounting | wearing detection sensor, reading of a manuscript image, etc. FIG. FIG. 3 is a first block diagram relating to control of the reading unit 10 and the automatic document feeder 20 when a paper feed tray is attached / detached. 6 is a flowchart relating to control of the reading unit 10 and the automatic document feeder 20 when the paper feed tray is attached / detached in the image forming apparatus. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 4 Platen glass 10 Reading part 11 Scanning unit 20 Automatic document conveying apparatus 22 Feeding roller pair 23 Separation feeding roller pair 24 Registration roller pair 26 Conveying drum 40 Paper feeding part 80 Control part 401 1st paper feeding tray 402 1st 2 paper feed tray 403 3rd paper feed tray 801 CPU
802 RAM
803 ROM
D Document S1 First mounting detection sensor S2 Second mounting detection sensor S3 Third mounting detection sensor

Claims (2)

An automatic document feeder for conveying a document;
A mounting table on which a document is placed;
A reading unit for reading an image of a document;
A storage unit for storing an image read by the reading unit;
A paper feed unit for feeding paper,
In an image forming apparatus having a control unit,
The paper feed unit includes a paper tray that stores paper, and a mounting detection sensor that detects that the paper tray is mounted,
The control unit scans the reading unit to read an image of a document which is placed on the mounting table and is stationary, in a first mode in which the document is conveyed by the automatic document conveying device and an image of the document is read. in the second mode, if executed to read the original image, attachment and detachment of the sheet tray is detected by the attachment detection sensor before Symbol first mode during execution, the transport of the document by the automatic document feeder and The reading of the original image by the reading unit is stopped, the image data of the original for which reading has been stopped is deleted from the storage unit, the original of which reading has been stopped is sent back to the conveyance start position, and the reading is performed again. When attachment / detachment of the paper tray is detected by the attachment detection sensor during execution of the second mode, scanning of the scanning unit of the reading unit and reading of an image of a document by the reading unit are performed. And Rio discontinued, which deletes the image data of the document stops reading from the storage unit, reads again after moving the scanning unit of the reading unit to the home position,
When the attachment / detachment detection of the attachment detection sensor is attachment, the control unit immediately re-conveys the document that has been fed back to the conveyance start position and executes an image of the document during execution of the first mode. An image forming apparatus , wherein during scanning and execution of the second mode, scanning of the scanning unit moved to the home position is immediately resumed and an image of a document is read by the reading unit. When the detection of attachment / detachment of the attachment detection sensor is attachment / detachment,
During execution of the first mode, after a predetermined time has elapsed from when the attachment detection sensor detects attachment / detachment, the document that has been fed back to the conveyance start position is re-conveyed to read an image of the document,
During execution of the second mode, after a predetermined time has elapsed since the attachment detection sensor detected attachment / detachment, scanning of the scanning unit moved to the home position is resumed, and an image of the document is read by the reading unit. The image forming apparatus according to claim 1, wherein the image forming apparatus reads the image forming apparatus.

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