JP2006259177A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus capable of performing image forming operation in a state where a phase is correctly detected/adjusted without performing phase detecting operation while rotating a photoreceptor in a period from receiving a printing request from a user until starting the image forming operation. <P>SOLUTION: The image forming apparatus is equipped with a phase detecting means for detecting the phases of the respective photoreceptors and a phase adjusting means for adjusting so that the phases of the respective photoreceptors may have predetermined phase relation to each other, and forms an image by superposing and transferring respective toner images formed on the respective photoreceptors whose phases are adjusted to have the predetermined phase relation by the phase adjusting means and which are driven and rotated while keeping the relation to a transfer medium. In the image forming apparatus, the phase detecting means detects the phases of the respective photoreceptors as an absolute phase angle by an absolute type rotary encoder when the respective photoreceptors are stopped. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to an image forming apparatus suitable for a printer apparatus, a facsimile apparatus, a copying machine, a multifunction machine, and the like, and particularly relates to rotational phase detection of each photoconductor.
The present invention relates to.

  A general configuration of the image forming unit of the image forming apparatus is shown in FIG.

  An image forming unit 9 shown in the figure is a unit for forming an image by an electrophotographic method while being controlled as necessary by a control unit such as a CPU via a system bus 14. This is a so-called tandem type in which image forming mechanisms corresponding to the respective color components are arranged in parallel. The tandem type has the advantage that high-speed color image formation is possible compared to the type in which the toner image of each color component is formed and transferred by a single image formation mechanism, but it is sensitive to each color component. Accuracy is required for the mutual positional relationship between the bodies.

  An image forming mechanism corresponding to each of a plurality of color components (magenta: M, cyan: C, yellow: Y, black: K) is provided on a conveying belt 1002 for placing and conveying a transfer sheet 1001 as a transfer medium. The conveyor belts 1002 are arranged in parallel with each other along the conveyance direction.

  The conveyor belt 1002 is constructed by a driving roller 1003 that rotates and a driven roller 1004 that rotates and is driven to rotate in the direction of arrow A by the rotation of the driving roller 1003. A paper feed tray 1005 in which transfer paper 1001 is stored is provided at the lower part of the conveying belt 1002 facing the image forming mechanism corresponding to each color component. Of the stored recording papers, the uppermost recording paper is sequentially fed by a paper feeding mechanism (not shown) at the time of image formation, and is sucked and placed on the transport belt 1002 as transfer paper 1001 by electrostatic suction. The transfer sheet 1001 that is placed and transported by suction is transported (sub-scanned) and reaches the position of the image forming mechanism (corresponding to the color component magenta (M) in this case) arranged at the uppermost stream in the transport path. Further, while being conveyed (sub-scanned), it passes through an image forming mechanism corresponding to each color component of cyan (C), yellow (Y), and black (K).

  The image forming mechanism corresponding to the color component M includes a photosensitive drum 1006M that is rotated by a photosensitive drum driving mechanism (not shown) so that the peripheral speed matches the conveying speed of the conveying belt 1002, and the photosensitive drum 1006M around the photosensitive drum 1006M. The arranged charger 1007M for uniformly charging the outer peripheral surface of the photosensitive member, and the outer peripheral surface of the photosensitive drum constituting the image forming mechanism corresponding to the single color image of each color component constituting the image data to be formed, A writing control unit 1008 (a common configuration for each color component) that forms an electrostatic latent image by irradiating with a laser beam modulated according to the content of a monochromatic image of each color component to remove electricity, and the formed electrostatic latent image After the toner image is transferred onto the transfer paper 1001 on the conveying belt 1002, the developing device 1009M forms the toner image on the photosensitive drum 1006M by adsorbing the toner onto the photosensitive drum 1006M. And a photoconductor cleaner 1010M for removing toner or the like remaining on the photosensitive drum 1006M.

  When the operation of the image forming mechanism for the color component M is viewed in time series, first, the surface of the photosensitive drum 1006M is uniformly charged by the charger 1007M, and then the monochrome image data of the color component M is obtained by the exposure control unit 1008. Is exposed (static elimination) with a monochromatic laser beam 1011M modulated in accordance with the above-described contents, and an electrostatic latent image is formed on the surface of the photosensitive drum 1006M. The formed electrostatic latent image is developed by the developing device 1009M (toner adsorption to the electrostatic latent image), and a toner image is formed on the photosensitive drum 1006M. The toner image is transferred by a transfer device 1012M disposed below the transfer position 1 at a position (transfer position) where the outer periphery of the photosensitive drum 1006M and the transfer sheet 1 on the conveying belt 1002 are in contact with each other. An image (in this case, magenta) is formed. Unnecessary toner remaining on the surface of the photoreceptor drum 1006M after the transfer is cleaned by the photoreceptor cleaner 1010M, and is prepared for image formation starting from the charging process by the next charger 1007M.

  The image forming mechanism corresponding to each color component of cyan (C), yellow (Y), and black (K) has the same configuration as the image forming mechanism corresponding to magenta (M) described above.

  If an image forming mechanism corresponding to the color component X (X = C, Y, KorM) is referred to as an image forming mechanism X, the transfer paper 1001 onto which the single color image of the color component M has been transferred by the image forming mechanism M is conveyed. The toner image corresponding to the image data of each color component constituting the image formation target image data passes through the transfer positions of the image forming mechanisms C, Y, and K in order while being further conveyed (sub-scanned) by the belt 1002. 1001 is superimposed and transferred. The transfer paper 1001 that has passed through the last image forming mechanism K is peeled off from the conveying belt 1002, and the toner image transferred by the heated fixing roller pair in the fixing device 1013 is firmly fixed on the transfer paper 1001. The paper is ejected.

  In this way, when the image forming unit 9 of the tandem method is used to form an image of a plurality of color components, that is, color formation target image data, the transfer paper 1001 has an image forming mechanism corresponding to each color component. Since the timing of passing does not necessarily match, the laser modulated in accordance with the writing start timing in the sub-scanning direction in the image forming mechanism corresponding to each color component, specifically, the content of the monochromatic image of each color component in the exposure control unit 1008 It is necessary to control the beam irradiation start timing so that the toner images of the respective color components are accurately superimposed on the transfer paper 1001 placed in close contact with the conveying belt 1002 at the transfer position in each image forming mechanism.

  However, a good transfer image cannot be obtained only by controlling the writing start timing.

  In other words, each of the photoreceptors 1006C, M, Y, and K, which ideally has a circular cross section and should be rotated around the center of the circle, is actually as shown in FIGS. 11 (a) and 11 (b). The center of rotation deviates from the ideal center (eccentric). The cause of the deviation is inevitably caused by the limit of manufacturing accuracy and / or assembling accuracy of each photoreceptor.

  When the rotation center is deviated, the peripheral speed of the outer periphery of the photosensitive member with respect to the transfer surface (conveying belt) 102 varies depending on the rotation phase. That is, the peripheral speed of the outer periphery of the photoconductor is different between the phase where the rotation radius of FIG. 11A is substantially maximum and the phase where the rotation radius of FIG. 11B is substantially minimum.

  Therefore, as shown in FIG. 12A, even if lines are written on the outer peripheral surfaces of the photoconductors 1006C, M, Y, and K as shown in FIG. Since the peripheral speed differs depending on the image, the writing interval, the variation in the formation interval due to the fluctuation in the peripheral speed is generated in the written / transferred / formed image as shown in FIG.

  If the peripheral speed is high, the writing time interval is shortened while the peripheral speed is low so that the peripheral speed fluctuations of the photosensitive bodies 1006C, M, Y, and K are offset. If the writing timing is varied in accordance with the phase of each photoconductor so as to increase the time interval, it is possible to prevent color misregistration due to the rotational phase shift of each photoconductor in the superimposed transfer / formed image.

  However, when image formation is performed without properly adjusting the phase relationship between the photoconductors to a predetermined relationship that serves as a reference for phase correction of writing timing, as shown in FIG. 13, superimposed transfer / formation (printing) is performed. In such an image, a color shift due to a rotational phase shift of each photoconductor occurs.

  As described above, it is very important to match the phase of each photoconductor with a predetermined phase relationship before starting the image forming operation in order to obtain a good superimposed image.

  For this purpose, an image forming process includes a phase detection operation that detects the phase of each photoconductor and a phase adjustment operation that adjusts the phase of each photoconductor detected by the phase detection operation to the predetermined phase relationship. This must be done prior to the start of operation.

  The phase detection operation is conventionally performed in the following steps.

  That is, when a print request from a user is received, the photosensitive member starts to rotate, and the rotation phase of each photosensitive member is detected. By this processing, the phase of each photoconductor is detected.

  Conventionally, phase detection in this case is generally performed by integrating pulses generated corresponding to the rotation angle of each photoconductor by an incremental rotary encoder with a measurement start point (detected by a photo interrupter or the like) as a base point. Is called.

  Further, the phase adjustment operation increases or decreases the rotation speed of each photoconductor so that each difference between the detected current rotation phase of each photoconductor and a predetermined phase relationship of each target photoconductor is offset. Is done.

  Conventionally, after a print request is made by a user and before a (net) image forming operation is started, such a phase detection operation and a phase adjustment operation are performed, and then a (net) image forming operation is started to form an image. And the operation of discharging the printed matter outside the apparatus was performed.

In such a conventional method, the phase detection / adjustment operation of the photoconductor is performed from when the print request is received from the user until the actual printing is performed (until the net image forming operation is started). From the viewpoint of the user, there is a problem that it takes a long time to obtain a desired printed matter.

Patent documents 1 and 2 can be mentioned as publicly known technology relevant to the present invention.
JP 2004-144919 A JP 2002-014504 A

  As described in Patent Documents 1 and 2, various methods have been proposed for shortening the phase matching time.

  However, in both cases, the phase detection operation is performed by rotating the photoconductor between the time when the print request is received from the user and the time when the image forming operation is actually started, so that the time required for the phase detection operation is reduced. Even if it was attempted, it was still necessary to perform the operation before starting the image forming operation, and the fundamental solution of the problem that the waiting time of the user was increased by the amount of the operation time was not made. .

  The present invention has been made in view of such circumstances, and the phase detection / adjustment is correctly performed without the phase detection operation by rotating each photoconductor between the time when the print request is received from the user and the time when the image forming operation is started. An object of the present invention is to provide an image forming apparatus capable of performing an image forming operation in a state in which the image forming apparatus is in contact.

  The image forming apparatus according to claim 1 includes a plurality of photoconductors, a phase detection unit that detects a phase of each photoconductor, and a phase of each photoconductor based on a detection result by the phase detection unit. Phase adjusting means for adjusting the phase relationship so that each phase is adjusted to the predetermined phase relationship by the phase adjusting means, and each photoconductor that is rotationally driven while maintaining that relationship. In the image forming apparatus for forming an image by superimposing and transferring the toner images formed on the transfer medium, the front phase detecting means is configured to set the phase of each photoconductor by an absolute rotary encoder when each photoconductor is stopped. It is detected as an absolute phase angle.

  According to a second aspect of the present invention, in the image forming apparatus of the first aspect, the phase adjusting unit includes a rotation start timing of a photoconductor as a reference for phase adjustment of the photoconductors, and The rotation start timing of the other photoconductors is adjusted based on the detection phase for each photoconductor by the phase detection means, thereby adjusting the phase of each photoconductor to the predetermined phase relationship. Characterized by

  According to a third aspect of the present invention, there is provided the image forming apparatus according to the first or second aspect, wherein a plurality of photoconductors that are linked and driven by a single driving unit as a part of each of the photoconductors. And a plurality of photoconductors that are driven in conjunction with each other are handled as a single photoconductor in terms of phase detection in the phase detection means and phase adjustment in the phase adjustment means.

  According to a fourth aspect of the present invention, in the image forming apparatus according to the second aspect of the present invention, a reference photoconductor that is a photoconductor serving as a reference for phase adjustment among the photoconductors. A reference photosensitive member setting unit for setting any one of them is provided.

  An image forming apparatus according to a fifth aspect is the image forming apparatus according to the second aspect, wherein the reference photoconductor that has the predetermined phase relationship with respect to the phase of each photoconductor and each other photoconductor. A phase difference setting means for setting each phase difference is provided.

  According to a sixth aspect of the present invention, in the image forming apparatus according to the fourth aspect of the present invention, the image forming apparatus further includes a storage unit that stores contents changed and set by the reference photosensitive member setting unit.

  According to a seventh aspect of the present invention, in the image forming apparatus according to the fifth aspect of the present invention, the image forming apparatus further includes a storage unit that stores contents changed and set by the phase difference setting unit.

  An image forming apparatus according to an eighth aspect of the present invention is the image forming apparatus according to the fourth or sixth aspect, wherein the reference photosensitive member setting unit is configured to perform the reference according to an operation input from another apparatus via a network. A photosensitive member is set.

  The image forming apparatus according to claim 9 is the image forming apparatus according to claim 5, wherein the phase difference setting unit is configured to output the phase difference in response to an operation input from another apparatus via a network. Is set.

  An image forming apparatus according to a tenth aspect is the image forming apparatus according to the fourth or sixth aspect, wherein the reference photosensitive member setting unit sets the reference photosensitive member according to an operation input in the apparatus. It is characterized by being.

  An image forming apparatus according to an eleventh aspect is the image forming apparatus according to either the fifth or seventh aspect, wherein the phase difference setting means sets the phase difference in accordance with an operation input in the apparatus. It is characterized by being.

  According to the first aspect of the invention, by applying an absolute rotary encoder as the previous phase detection means, the phase of each photoconductor can be detected as an absolute phase angle when each photoconductor is stopped. Therefore, the detection while rotating each photoconductor is unnecessary as compared with the case of detecting the phase angle of the angular photoconductor by combining the detection of the rotation reference position and the detection of the relative phase angle by the incremental encoder. Accordingly, the time required for phase detection can be shortened, and the effect of shortening the time required for image formation when viewed from the user can be obtained.

  According to the second aspect of the present invention, the phase detection means adjusts the phase by adjusting the rotation start timing of each photoconductor using the fact that the phase of each photoconductor can be detected while each photoconductor is stopped. As a result, phase adjustment can be performed with the minimum necessary adjustment time, and the time required for image formation when viewed from the user can be further shortened.

  According to the third aspect of the present invention, the effect of applying the present invention can be obtained when a plurality of photoconductors that are interlocked and driven by a single driving unit are included as a part of each photoconductor. .

  According to the fourth aspect of the present invention, it becomes possible to select a photoconductor as a reference for phase adjustment. Therefore, even if the photoconductor unit as a reference for phase alignment is replaced and the eccentricity characteristic is changed, By selecting the photoconductor, it is possible to shorten the phase matching time.

  According to the fifth aspect of the present invention, the phase difference for phase alignment between the photoconductor as a reference for phase alignment and another photoconductor can be selected, so that the life of the transfer belt and the photoconductor is not shortened. Such a phase relationship can be set, and the effect that the lifetime of the apparatus can be extended is obtained.

  According to the sixth aspect of the invention, since the setting of the reference photoconductor is held, in each image forming operation after setting, the setting of the reference photoconductor is not performed again for each image forming operation. There is an effect that the phase can be adjusted based on the set reference photoconductor.

  According to the seventh aspect of the invention, since the setting of the phase difference is maintained, the setting is made in each image forming operation after setting without performing the setting of the phase difference again for each image forming operation. The effect that the phase adjustment by the phase difference becomes possible is obtained.

  According to the eighth aspect of the present invention, the reference photoconductor can be set from another apparatus that is remote from the image forming apparatus according to the present invention.

  According to the ninth aspect of the present invention, the setting of the phase difference can be performed from another apparatus remote from the image forming apparatus according to the present invention.

  According to the tenth aspect of the present invention, the reference photoconductor can be set by an operation input from the image forming apparatus main body according to the present invention.

  According to the eleventh aspect, the phase difference can be set by an operation input from the image forming apparatus main body according to the present invention.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 shows a system configuration including an image forming apparatus 1 according to the best mode for carrying out the present invention.

  In FIG. 1, the image forming apparatus 1 can transmit and receive image data to and from the facsimile apparatus 201 on the PSTN 200 via the PSTN 200. Further, if the image forming apparatus 1 has an interface with the ISDN 300, it is possible to transmit / receive image data to / from the facsimile apparatus 301 on the ISDN 300 (in the best mode for carrying out the present invention). Absent). The image forming apparatus 1 is connected to the LAN 500 and connected to the Internet 400 via a router device 502 that performs packet conversion. The image forming apparatus 1 transmits and receives image data by e-mail to and from the personal computer 402 on the Internet 400, and the Internet. E-mail with the network facsimile apparatus 401 on the T.400 and ITU-T recommendation T.264. The image data can be transmitted and received by real-time network facsimile communication based on H.38. The image forming apparatus 1 can exchange image data with personal computers (PCs) 501a, 501b, 501c, etc. on the LAN 500.

  In other words, the image forming apparatus 1 is provided with a composite function as a normal facsimile apparatus via a public line, a network facsimile apparatus, a scanner apparatus for the PC 501a and the like, a printer apparatus for the PC 501a and the like, a copier, and the like. is there.

  FIG. 2 shows a block configuration of the image forming apparatus 1.

  In the figure, a CPU 2 is a central processing unit that controls each part of the apparatus, performs various data processing, and performs protocol control based on a control program written in the ROM 3 while using a RAM 4 as a work area. .

  The ROM 3 is a read-only memory that stores various data necessary for control such as a control program for the CPU 2 to control each part of the apparatus and font data corresponding to each character code.

  The RAM 4 is a random access memory used as a work area for the CPU 2 as described above.

  An EEPROM (electrically rewritable read-only memory) 5 is a memory for storing various information necessary for the operation of the apparatus and holding the stored contents even when the apparatus is turned off. Replacement with a backed up SRAM (static RAM) or a magnetic disk device is also possible.

  The clock circuit 6 always keeps track of the current date and time, and the CPU 2 can read the clock circuit 6 via the system bus 14 to know the current date and time (date and time).

  The operation display unit 7 is provided with various keys for accepting operation inputs from the user, and includes a display such as a liquid crystal display device, and displays an operation state of the device to be notified to the user and various messages. It is.

  The reading unit 8 reads image data and obtains image data. The configuration of the reading unit 8 will be described in detail later.

  The image forming unit 9 is for printing out image data on recording paper, and has the configuration shown in FIG. 10 which has already been described.

  The image processing unit 10 encodes and compresses raw image data and decodes / decodes the encoded compressed data, binarization process, scaling process, reduction / enlargement process, and image correction process. Various processing related to image data handled in the image forming apparatus 1 is performed, such as rearrangement processing of the pixel order in each main scanning line constituting the image data, addition processing of additional information such as character string information of transmission date / time and reception date / time. .

  The LAN communication control unit 10 is a so-called NIC (Network Interface Card), and is connected to the LAN 500 so that various information can be exchanged by the upper protocol by the exchange of the TCP / IP protocol by the CPU 2 on the LAN protocol. It is for making.

  The communication control unit 12 is connected to the PSTN 200 via the NCU unit 13 and controls communication with the counterpart communication terminal. The communication control unit 12 controls the NCU unit 13 to detect a ringing voltage pulse detected by the NCU unit 13, a DTMF signal, a tone signal, and a call at the time of transmission. Further, the communication control unit 12 has a modem, and demodulates reception data (modulated) received from the counterpart communication terminal, or conversely modulates and transmits transmission data at the time of transmission. . Specifically, ITU-T recommendation T.I. A low-speed modem function (V.21 modem) for exchanging G3 facsimile control signals based on G.30 and a high-speed modem function mainly for exchanging document image data. 17, V.R. 33, V.R. 34, V.R. 29, V.R. It has 27ter modem functions.

  The NCU unit 13 is connected to the PSTN 200, and closes the line and detects a call signal (ringing).

  The system bus 14 is a signal line composed of a data bus, an address bus, a control bus, an interrupt signal line, and the like for the above units to exchange data.

  With the above configuration, the image forming apparatus 1 forms and outputs image data on a recording sheet as a printer apparatus, as a receiving side of a facsimile apparatus, or as a copying machine. The image formation is performed as described above. This is performed by the image forming unit 9.

  FIG. 3 is a schematic diagram that focuses on the rotational drive of each photoconductor in the image forming unit 9 of the image forming apparatus 1.

  In the figure, a photoconductor group 1006 composed of photoconductors 1006C, M, Y, and K is a drive device composed of drive devices 1030C, M, Y, and K each composed of a DC motor or the like. The group 1030 is independently driven to rotate.

Conventionally, the rotation phase of each photoconductor is generally detected by integrating the pulses generated corresponding to the rotation angle of each photoconductor with an incremental rotary encoder using the measurement start point (detected by a photo interrupter or the like) as a base point. However, in the best mode for carrying out the present invention, as shown in FIG. 4, an absolute type rotary encoder 40 is connected to each of the photoconductors 1006C, M, Y, and K, respectively. In this photoconductor, the phase of each photoconductor can be detected while the photoconductor is stopped.

  The absolute encoder 40 is provided by an indicating member 43 fixed to the apparatus main body with a plurality of slits formed on a slit disk attached to the end of the rotating shaft 41 of each photoconductor 1006C, M, Y, K. The light receiving element 45 detects transmission and shading with the threads of the light emitted from the correspondingly arranged light emitting elements 44, so that the absolute phase of each photoconductor can be immediately detected without the need to detect the passage of the reference point. It can be detected.

  FIG. 5 schematically shows the principle of absolute phase detection in a general absolute type rotary encoder.

  As shown in the figure, the absolute type rotary encoder has a unique reading result for each phase, so it can detect the phase even when the rotation is stopped, and does not need to be rotated like a conventional incremental type encoder. . Therefore, by detecting the phase of the photosensitive member with an absolute rotary encoder, the time until the start of printing can be shortened as shown in FIG.

  In FIG. 6, in the best mode (proposed method) for carrying out the present invention, in the “conventional method”, it is necessary to perform the phase while rotating each photoconductor before the start of the printing (image forming) operation. Of the two operations of the detection operation and the phase alignment (adjustment) operation following the phase detection operation, the phase detection operation while rotating is omitted before the start of the printing (image forming) operation. However, the phase detection operation without rotating the photoconductor is performed before the start of the printing (image forming) operation, and before the phase adjustment operation while rotating the photoconductor.

  Thereby, the time for the phase detection operation while rotating can be shortened. In that case, from the viewpoint of the user, since the phase detection operation while rotating is unnecessary, the waiting time until the actual printing operation is started after the instruction to start printing is shortened. Can be obtained without a long waiting time (phase detection operation while rotating).

  FIG. 7 shows the storage contents characteristic of the present invention in the EEPROM 5 of the image forming apparatus 1.

  In the drawing, “phase adjustment reference photoconductor identification information” is set in the storage area 5a of the EEPROM 5, and the value “0 (K)” is currently set. The “phase adjustment reference photoconductor identification information” can take any of the values 0 (K), 1 (C), 2 (M), and 3 (Y), and the photoconductor that is the reference for phase adjustment. Information for setting and storing.

  The "reference photoconductor phase difference setting information" in the storage area 5b sets the phase difference to be set for each of the other photoconductors with reference to the phase of the "phase adjustment reference photoconductor" set in the storage area 5a. A “set phase difference” is set for each of the photoconductors having values 0 to 3 defined as in the case of the identification information 5a.

  Specifically, for a photoconductor having a value of 0 (K), the “set phase difference” is meaningless because it is currently set as the reference photoconductor in the storage area 5a. For the photoreceptor of value 1 (C), “+ 20 °” is set as the “set phase difference”. For the photoreceptor of value 2 (M), “+ 25 °” is set as the “set phase difference”. For the photoreceptor of value 3 (Y), “+ 50 °” is set as the “set phase difference”.

  Here, the significance of setting the “phase adjustment reference photoconductor identification information” in the storage area 5a will be described.

  Some color image forming apparatuses having a plurality of photoconductor units may replace a plurality of photoconductors at once, while others may replace them individually. In the replacement of the individual photoconductors, when the photoconductor which is a reference for phase alignment is replaced, the other photoconductors (i.e., photoconductors having no phase) are used as a reference. It is unreasonable to phase the photoconductor (which should be in phase because it has not been replaced).

  As in the best mode for carrying out the present invention, by setting the “phase adjustment reference photoconductor identification information” in the storage area 5a, it becomes possible to select a photoconductor as a reference for phase alignment, so that the reference and The phase selection time can be shortened by the user selecting another photoconductor (that is, any photoconductor that has not been replaced) and changing the photoconductor.

  Here, the significance of setting the “reference photoconductor phase difference setting information” in the storage area 5b will be described.

  In the image forming apparatus having a plurality of photoconductors, as described above, since each photoconductor is eccentric, an impact to the belt is generated. There are various modes of impact generation in this case, but all the photoconductors simultaneously apply an impact to the belt. One photoconductor gives an impact to the belt, and that part is the next photoconductor as the belt is conveyed. The impact is applied in the mode in which the impact is given to the same part (by the next photoconductor) when it is sent to the motor, the mode in which the entire belt moves undulating due to the different phases of each photoconductor, etc. May occur.

  Actually, the manner in which the impact is generated varies depending on each product, but the belt may be deteriorated by this impact.

  Therefore, in the best mode for carrying out the present invention, a belt can be selected for each model / product so that a user can select a phase difference between a photoconductor as a reference for phase alignment and another photoconductor. In addition to alleviating the impact on the ink and improving the print quality, it is possible to realize control that maintains the life of the transfer belt and the photosensitive member.

  FIG. 8 shows a phase alignment related setting process procedure in the image forming apparatus 1.

  In the same figure, the CPU 2 receives a shift instruction operation input to the phase alignment related setting mode by a predetermined operation input from the operation display unit 7 of its own device or the phase alignment related via the LAN communication control unit 11. It is monitored whether an instruction to shift to the setting mode has arrived from another device via a network (LAN 100, Internet 400, etc.) (processing S101, determination S102 No, processing S104, determination S104 No loop).

  Then, in the determination S102, when there is an operation instruction input to shift to the phase alignment related setting mode (Yes in the determination S102), local dialogue setting input processing is performed (processing S103).

  On the other hand, in the determination S105, when an instruction to shift to the phase matching related setting mode arrives (Yes in the determination S105), remote dialog setting input processing is performed (processing S106).

  The local dialog setting input process of the process S103 is a process for interactively setting and storing the setting contents of the storage areas 5a to 5b in FIG. 7 via the operation display unit 7.

  In the remote dialog setting input process in step S105, the setting contents of the storage areas 5a to 5b in FIG. 7 are set interactively by exchanging with other devices (for example, the PC 101a in FIG. 1) via the LAN communication control unit 11. It is a process to memorize.

  As described above, the user can change the settings of FIG. 5 directly from the own apparatus (image reading apparatus 1) or indirectly from another apparatus via the network, and perform phase detection and phase adjustment under appropriate conditions. The image forming apparatus 1 can perform this.

  The interface between the other apparatus and the image forming apparatus 1 is not limited to a general network such as the LAN 100 or the Internet 400, but a general-purpose interface that can be used as a standard in a personal computer, such as USB and IEEE 1394, is applied. You may do it. In addition, it is only necessary that commands and responses can be exchanged between the image forming apparatus 1 and another apparatus such as a PC such as an in-house dedicated line or an IP network. The other apparatus is not limited to the PC, and may be another image forming apparatus.

  FIG. 9 shows an image forming operation control processing procedure in the image forming apparatus 1.

  In the figure, the CPU 2 performs a phase detection operation of detecting each phase θKθCθMθY of each photoconductor 106CMYK by the encoder 40 having the configuration shown in FIG. 4 in a state where each photoconductor is stopped (step S201). A phase matching (adjustment) operation is performed to increase or decrease the rotational speed of each photoconductor until the detected phase of each photoconductor satisfies the phase difference condition set in the storage area 5b of FIG. 7 (processing S207). Subsequently, the printing operation is performed (processing S203).

  The phase adjustment (adjustment) operation of the process S207 is set in the storage area 5b of FIG. 7 by taking advantage of the best mode feature for carrying out the present invention that can be detected while the phase of each photoconductor is stopped. By shifting the rotation start timing of each photoconductor based on the relationship between the phase difference and the current phase of each photoconductor detected in step S201, the phase difference set from the rotation start time is obtained. By doing so, the time for the phase adjustment operation can be shortened, and the waiting time of the user can be reduced accordingly. Specifically, in the phase adjustment operation, the rotation of the “reference photosensitive member” set in the storage area 5a in FIG. 7 is started first, and the position of the “reference photosensitive member” and the other photosensitive members is determined. When each phase difference reaches each phase difference set in the storage area 5b of FIG. 7, the rotational driving of each photoconductor is started. In this case, even if a deviation from the set phase difference occurs due to variations in the inertia of each photoconductor or driving force at the start of rotation, the deviation is slight and can be corrected in a relatively short time by adjusting the rotation speed.

  In the present invention, in addition to the configuration in which each photoconductor shown in FIG. 3 is driven to rotate independently, a part of each photoconductor shown in FIG. 10 (in this case, three photoconductors 1006C, M, and Y). It is obvious that the present invention can also be applied to a configuration in which driving is interlocked by a common driving device 1030CMY.

  That is, for phase detection and phase adjustment, the three photoconductors 1006C, M, and Y that are linked to each other are regarded as one photoconductor to be phase-detected and phase-adjusted, so that phase detection and phase adjustment according to the present invention can be performed. Can be applied.

  Although the best mode for carrying out the present invention has been described above, it is needless to say that the present invention is not limited to the above and can be variously modified without departing from the gist thereof. .

1 is a diagram showing a system configuration including an image forming apparatus according to the best mode for carrying out the present invention. 1 is a diagram showing a block configuration of an image forming apparatus according to the best mode for carrying out the present invention. 1 is a schematic diagram illustrating a configuration of an image forming unit of an image forming apparatus according to the best mode for carrying out the present invention. It is a figure shown about detection of a photoconductor rotation phase with an absolute type rotary encoder. It is a schematic diagram which shows the principle which detects a phase angle as an absolute value by an absolute rotary encoder. It is a figure for demonstrating the advantage with respect to the conventional method of the best form for implementing this invention. FIG. 3 is a diagram showing the contents stored in the EEPROM of the image forming apparatus according to the best mode for carrying out the present invention. 5 is a flowchart showing a registration related setting processing procedure in the image forming apparatus according to the best mode for carrying out the present invention. 6 is a flowchart illustrating an image forming operation control processing procedure in the image forming apparatus according to the best mode for carrying out the present invention. FIG. 6 is a schematic diagram illustrating another example of the configuration of the image forming unit of the image forming apparatus according to the best mode for carrying out the invention. FIG. 3 is a diagram illustrating a configuration of an electrophotographic image forming unit. FIG. 6 is a diagram for explaining fluctuations in the peripheral speed of a transfer surface due to a shift in the rotation center of a photoconductor. FIG. 10 is a diagram showing that transfer intervals are not uniform even if writing is performed at equal intervals due to a shift in the rotation center of the photoconductor. FIG. 6 is a diagram illustrating that even when writing is performed at equal intervals, transfer intervals are not uniform and colors are shifted from each other due to a phase shift of each photoconductor corresponding to each color component.

Explanation of symbols

1 Image forming apparatus 9 Image forming unit

Claims (11)

Phase adjustment for adjusting a plurality of photoconductors, a phase detection unit for detecting the phase of each photoconductor, and a phase of each photoconductor to have a predetermined phase relationship based on a detection result by the phase detection unit Each toner image formed on each photoconductor that is rotationally driven while the phase is adjusted to the predetermined phase relationship by the phase adjusting unit and the relationship is maintained. In an image forming apparatus that forms an image by superimposing and transferring to
The front phase detection means detects the phase of each photoconductor as an absolute phase angle by an absolute rotary encoder when each photoconductor is stopped.   The phase adjusting means detects the rotation start timing of a photoconductor as a reference for phase adjustment among the photoconductors and the rotation start timing of other photoconductors for each photoconductor by the phase detection means. The image forming apparatus according to claim 1, wherein the phase of each photoconductor is adjusted to the predetermined phase relationship by adjusting based on the phase.   As a part of each of the photoconductors, a plurality of photoconductors that are driven in conjunction by a single drive unit are included, and the plurality of photoconductors that are driven in conjunction with each other in the phase detection unit and the phase adjustment unit. The image forming apparatus according to claim 1, wherein the image forming apparatus is handled as a single photoconductor with respect to phase adjustment.   3. The reference photoconductor setting means for setting any one of the photoconductors as a reference photoconductor that is a photoconductor serving as a reference for phase adjustment among the photoconductors. The image forming apparatus described.   3. The phase difference setting means for setting each phase difference between the reference photoconductor and the other photoconductors having the predetermined phase relationship with respect to the phase of each photoconductor. Image forming apparatus.   5. The image forming apparatus according to claim 4, further comprising a storage unit that stores contents changed by the reference photosensitive member setting unit.   The image forming apparatus according to claim 5, further comprising a storage unit that stores contents changed by the phase difference setting unit.   7. The image forming apparatus according to claim 4, wherein the reference photosensitive member setting unit sets the reference photosensitive member in response to an operation input from another device via a network. .   The image forming apparatus according to claim 5, wherein the phase difference setting unit sets the phase difference in response to an operation input from another apparatus via a network.   The image forming apparatus according to claim 4, wherein the reference photoconductor setting unit sets the reference photoconductor in response to an operation input in the apparatus.   The image forming apparatus according to claim 5, wherein the phase difference setting unit sets the phase difference according to an operation input in the apparatus.

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