JP2008089647A - Printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer which shortens the first print time by determining a color of a developer from print data and controlling stop of conveyance of a printing medium in accordance with an image forming unit provided with the developer in the color for use. <P>SOLUTION: A reception part 401 determines the color of the developer for use, from print data. A driving part rotationally drives a photoreceptor of an image forming unit having the developer in the color for use on the basis of an amount of rotation managed by a medium print management part 403 so that an outer peripheral surface potential of the photoreceptor reaches a prescribed level. A medium conveyance control part 405 conveys the printing medium so that the printing medium reaches the image forming unit having the developer in the color for use after the photoreceptor is rotated by the amount of rotation to cause the surface potential of the photoreceptor to reach the prescribed level, whereby the first print time is shortened. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a printing apparatus in which a plurality of image forming units are arranged side by side in the conveyance direction of a printing medium.

  In general, an electrophotographic printing apparatus performs a process such as charging, exposure, and development on each photoconductive drum of a plurality of image forming units, and outputs a toner image with toner as a developer formed on the photoconductive drum. A printed matter is created by transferring it to a printing medium (see, for example, Patent Document 1). In this process, a certain stabilization time is required to bring the surface potentials of all of the plurality of photosensitive drums to a predetermined level before the exposure is started. The print medium is conveyed to the image forming unit after the stabilization time has elapsed, and the toner image is transferred thereto.

JP 2002-31656 A

  However, in the conventional printing apparatus including Patent Document 1, a certain stabilization time is required to set the surface potentials of all the photosensitive drums to a predetermined level before printing is started. There has been a problem that the time for printing on the first print medium after receiving print data (hereinafter referred to as the first print time) becomes long.

  Therefore, in view of the above circumstances, the present invention determines the color of the developer used for printing from the print data, and controls the stop of conveyance of the print medium according to the image forming unit including the developer of the color to be used. An object of the present invention is to provide a printing apparatus that shortens the first print time.

  The printing apparatus of the present invention is arranged in each of the image forming units in a printing apparatus that prints by attaching a developer image based on print data to the print medium by a plurality of image forming units arranged in the conveyance direction of the print medium. Necessary for the potential of the outer peripheral surface of each of the photosensitive members to be a potential at which the developer image can be formed, and a potential control unit that controls a potential applied to the outer peripheral surface of each of the photosensitive members. Printing based on the print data, a rotation amount management unit that manages the rotation amount, a drive unit that rotationally drives each of the photosensitive members of the image forming unit, a medium conveyance control unit that controls conveyance of the print medium, and the print data A color to be used for printing determined by the print color determination unit managed by the rotation amount management unit. Before Based on the amount of rotation required for the photosensitive body of the image forming unit, after the photosensitive member is rotated the amount of rotation, characterized in that for conveying the printing medium to the image forming unit of a color to be used for printing.

  According to the printing apparatus of the present invention, the print color determination unit determines the color of the developer used for printing from the print data. Then, based on the rotation amount managed by the rotation amount management unit, the drive unit removes the photoconductor so that the outer peripheral surface of the photoconductor of the image forming unit having the developer of the color to be used has a predetermined level of surface potential. Drive to rotate. At this time, the medium conveyance control unit conveys the photosensitive member so as to reach an image forming unit having a color developer that uses the print medium after rotating by a rotation amount for the surface potential of the photoreceptor to reach a predetermined level. Accordingly, the first print time can be shortened by controlling the stop of the conveyance of the print medium according to the image forming unit including the developer of the color to be used.

  The printing apparatus of the present invention will be described below with reference to the drawings. The printing apparatus of the present invention is not limited to the following description, and can be appropriately changed without departing from the gist of the present invention.

[Embodiment 1]
FIG. 1 is a diagram illustrating a configuration of a printing apparatus according to the present invention. The apparatus main body 210 of the printing apparatus of the present invention includes a tray 221, a multi-purpose tray 222, paper feed sensors 223 and 224, a transport sensor 225 as a medium position determination unit, a transport belt 232, an image forming unit 226, 227, 228, 229, a fixing unit 230, a discharge sensor 231, and an interface connector 236.

  The tray 221 includes a predetermined amount of paper 233 as a print medium in the apparatus main body 210 and feeds the paper 233 to the apparatus main body 210. The multi-purpose tray 222 feeds the paper 233 from outside the apparatus main body 210. The paper feed sensor 223 detects the paper 233 fed from the tray 221, and the paper feed sensor 224 detects the paper 233 fed from the multipurpose tray 222. The transport sensor 225 detects the transport state of the paper 233 fed from the tray 221 or the multipurpose tray 222 and transported along the transport path 235. The sheets 233 fed from the tray 221 and the multi-purpose tray 222 are separated one by one by a separating member or the like, detected by the sheet feeding sensor 223 or the sheet feeding sensor 224, and also conveyed by the transport sensor 225. Detected and fed to the conveyor belt 232. The paper 233 fed to the transport belt 232 is transported in the order of the image forming units 226, 227, 228 and 229 via the transport belt 232.

  An image forming unit 226 that forms black toner images with black toner, an image forming unit 227 that forms yellow toner images with yellow toner, and an image that forms magenta toner images with magenta toner The image forming unit 229 that includes cyan toner and forms a cyan toner image is arranged in order from the insertion side of the paper 233 toward the discharge side. The image forming unit 226 will be described as an example. As shown in FIG. 2, the image forming unit 226 includes a photosensitive drum 300, a charging roller 301, an LED head 302, a developing roller 303, and a transfer unit. The image forming apparatus includes a transfer roller 304, a toner supply roller 305, and a toner cartridge 306. The photosensitive drum 300 rotates in the direction of the arrow, and the charging roller 301 to which a predetermined potential is applied contacts the photosensitive drum 300 and charges the surface of the photosensitive drum 300 so as to have a uniform potential. The LED head 302 exposes the surface of the photosensitive drum 300 having a uniform electric potential of a predetermined level according to the print data, and forms an electrostatic latent image. The developing roller 303 is in contact with the photosensitive drum 300, develops the electrostatic latent image with toner supplied from the toner cartridge 306 via the toner supply roller 305, and forms a toner image on the photosensitive drum 300. Let When the sheet 233 is conveyed between the conveyance belt 232 and the photosensitive drum 300, the image forming unit 226 applies a transfer bias to the transfer roller 304 disposed on the back surface of the conveyance belt 232, and the photosensitive drum 300. The upper toner image is transferred to the paper 233. The image forming unit 226 is driven by an individual drive motor (not shown). The image forming units 227, 228, and 229 have the same mechanism as that of the image forming unit 226 except that the toner colors are different. The sheet 233 is conveyed to the image forming units 227, 228, and 229 via the conveying belt 232, and the toner images are sequentially applied to the sheet 233 in the same manner as the image forming unit 226 in accordance with the timing at which the sheet 233 is conveyed. Transfer in layers.

  In the fixing unit 230, the paper 233 conveyed by the conveying belt 232 is sandwiched between the fixing roller and the pressure roller, heated, and pressed to fix the toner of each color on the paper 233. The sheet 233 on which the toner image is fixed by the fixing unit 230 is detected by the discharge sensor 231 and is conveyed along the conveyance path 235 toward the discharge tray on the discharge side of the sheet 233 of the apparatus main body 210. It is discharged outside the apparatus main body 210.

  FIG. 3 is a control block diagram showing the internal configuration of the printing apparatus of the present invention. As shown in FIG. 3, the printing apparatus of the present invention includes a receiving unit 401 having a print color determining unit, a controller unit 402 as a drive unit, a medium print management unit 403 as a rotation amount management unit, and a paper feed control unit. 404, a medium conveyance control unit 405, an image formation control unit 406 as a potential control unit, and a discharge control unit 407.

  The printing apparatus of the present invention is connected to a host computer via an interface connector 236 such as a LAN (Local Area Network) or a USB (Universal Serial Bus), receives print data created by the host computer, and based on the print data To print on the paper 233.

  A receiving unit 401 receives print data created by a host computer. Then, the reception unit 401 analyzes the received print data. The receiving unit 401 analyzes the print data to determine the color of the toner used in printing based on the received print data. The receiving unit 401 passes the determined toner color information to the controller unit 402.

  The controller unit 402 is configured to start printing based on print data received and analyzed by the receiving unit 401, a medium print management unit 403, a paper feed control unit 404, a medium conveyance control unit 405, an image formation control unit 406, and The discharge control unit 407 is instructed to control the entire printing apparatus. In addition, the controller unit 402 receives toner color information used for printing from the reception unit 401 and passes the information to the medium print management unit 403.

  The medium print management unit 403 receives toner color information used for printing from the controller unit 402. Further, the medium print management unit 403 counts the rotation amount of the photosensitive drum 300. The photosensitive drum 300 needs to be stabilized so that the surface potential becomes a uniform potential of a predetermined level so that a toner image can be formed on the surface thereof. For this purpose, it is necessary to rotate the photosensitive drum 300 by a predetermined rotation amount. The medium print management unit 403 manages a necessary rotation amount. The medium print management unit 403 then moves the surface of the photosensitive drum 300 corresponding to a predetermined rotation amount required for stabilizing the surface potential and the toner used for printing after the paper 233 is fed. Of the image forming units to be used based on the color of the paper 233, the transport distance to the image forming unit on the upstream side in the transport direction of the paper 233 is compared. Then, the medium print management unit 403 passes the comparison result to the controller unit 402, and the controller unit 402 issues an instruction to each member based on the result. The medium print management unit 403 includes a print prohibition counter that prohibits printing and a print permission flag that permits printing according to the comparison result between the movement distance and the transport distance.

  The paper feed control unit 404 controls the paper 233 to be fed from the tray 221 and the multipurpose tray 222. The paper feed control unit 404 feeds the sheets 233 of the number required for printing one by one based on the print data received and analyzed by the receiving unit 401. Further, the paper feed control unit 404 recognizes that the paper feed is completed in response to detection of the fed paper 233 by the paper feed sensors 223 and 224.

  The medium conveyance control unit 405 detects the color of the toner used for printing and the conveyance status of the paper 233 by the conveyance sensor 225 provided on the upstream side of the conveyance belt 232 in the conveyance direction of the paper 233, and detects the conveyance belt 232. Stop, drive or control. The position where the transport sensor 225 is provided is the medium standby position. In the present invention, the sheet 233 conveys the distance from the position where the conveyance sensor 225 is provided to the position where the photosensitive drum 300 of the image forming unit used in printing based on the received print data and the conveyance belt 232 contact each other. The transport distance to be used. The medium conveyance control unit 405 transfers the fed paper 233 to each image forming unit 226 in accordance with the transfer timing of the toner image formed by the image forming units 226, 227, 228, and 229 based on the print data. 227, 228, and 229 are driven to drive the conveyor belt 232.

  As described above, the image forming control unit 406 forms a toner image on the photosensitive drum 300 based on the print data by each of the image forming units 226, 227, 228, and 229, and is conveyed by the conveying belt 232. Control is performed such that a member in the image forming unit is driven or a predetermined potential is applied so that the toner image can be transferred onto the sheet 233 at a predetermined position on the sheet 233. The image formation control unit 406 rotates the photosensitive drum 300 by a predetermined rotation amount so that the surface potential of the photosensitive drum 300 of each of the image forming units 226, 227, 228, and 229 is stabilized.

  The discharge controller 407 controls the fixing unit 230 in order to fix the toner image transferred to the paper 233 by heating and pressing. The discharge control unit 407 receives the detection of the discharge state of the paper 233 on which the toner image is fixed by the discharge sensor 231, and discharges the paper 233 to the outside of the apparatus main body 210 along the transport path 235.

  FIG. 4 is a diagram showing a charged state of toner on the surface of the photosensitive drum of the printing apparatus of the present invention. The photosensitive drum 300 of each of the image forming units 226, 227, 228, and 229 is charged on the surface thereof so as to have a uniform potential by the charging roller 301. The printing apparatus receives print data from the host computer, and immediately after the charging of the photosensitive drum 300 is started under the control of the controller unit 402 and the control of the image forming control unit 406, that is, the rotation of the photosensitive drum 300 starts. Immediately after being applied, as shown in FIG. 4, the toner is less charged and the surface potential of the photosensitive drum 300 is not stable. The degree of toner charging, that is, the stabilization of the surface potential of the photosensitive drum 300 depends on the amount of rotation of the photosensitive drum 300, that is, the moving distance of the surface of the photosensitive drum 300.

  As shown in FIG. 4, when the sheet 233 is conveyed between the photosensitive drum 300 and the transfer roller 304 by the conveying belt 232 in the area 501 where the toner charge is low, the transfer bias is not applied. The toner adheres to the paper 233, and the paper 233 becomes dirty. Therefore, in this area 501, the paper 233 cannot be passed between the photosensitive drum 300 and the transfer roller 304, and the rotation amount of the photosensitive drum 300 corresponding to this area 501 is set to the medium passing impossible distance 504. To do.

  In the region 502 where the toner charge is relatively large, even if the paper 233 is conveyed so as to pass between the photosensitive drum 300 and the transfer roller 304, no toner adheres to the paper 233 even if no transfer bias is applied. . In this area 501, paper can be passed between the photosensitive drum 300 and the transfer roller 304, and the rotation amount of the photosensitive drum 300 corresponding to this area 502 is defined as a medium paper passing distance 505.

  In the region 503 where the toner charge is large and constant, by applying a transfer bias, good transfer can be performed on the paper 233 that has been passed. The transfer of the toner image onto the sheet 233 is not performed until the photosensitive drum 300 is rotated by a predetermined rotation amount and the toner is charged in this region 503. That is, the photosensitive drum 300 needs to be rotated until it reaches the region 503, and the rotation amount of the photosensitive drum 300 corresponding to the boundary between the region 502 and the region 503 stabilizes the surface potential of the photosensitive drum 300. This is the predetermined amount of rotation necessary to make it happen. Then, by rotating this predetermined amount of rotation, the moving distance of an arbitrary portion of the surface of the photosensitive drum 300 is the moving distance of the surface of the photosensitive drum corresponding to the predetermined amount of rotation. In the printing apparatus of the present invention, after the photosensitive drum 300 of the image forming unit having the color of the toner used for printing is rotated by a predetermined rotation amount to reach the region 503, the image having the color of the toner used for printing is obtained. The sheet 233 is conveyed to the forming unit by the medium conveyance control unit 405. That is, the medium conveyance control unit 405 forms the image after the time required for the photosensitive drum 300 of the image forming unit having the color of the toner used for printing to rotate by a predetermined amount of time has passed. The sheet 233 is conveyed to the unit. Thereby, the first print time can be shortened.

  In the present invention, as shown in FIG. 2, the medium passing impossible distance 504 is the photosensitive drum 300 from the contact position between the photosensitive drum 300 and the developing roller 303 to the contact position between the photosensitive drum 300 and the transfer roller 304. The distance traveled by the surface portion, for example, 31 mm. The medium passing distance 505 is a distance traveled by an arbitrary position on the surface of the photosensitive drum 300 until the surface potential of the photosensitive drum 300 is stabilized after the toner does not adhere, for example, the photosensitive drum. It is set to 188 mm corresponding to 300 two rotations. That is, the moving distance of the photosensitive drum surface corresponding to a predetermined amount of rotation necessary for stabilizing the surface potential of the photosensitive drum 300 is 31 mm + 188 mm = 219 mm. Hereinafter, although it demonstrates using these distances, this invention is not limited to this.

  The controller unit 402 controls the conveyance of the sheet 233 by the medium conveyance control unit 405 and the transfer roller 304 of the image formation control unit 406 based on the rotation amount of the photosensitive drum 300 corresponding to each toner charging area described above. The transfer bias is controlled. At the medium non-passable distance 504, the medium conveyance control unit 405 causes the conveyance belt to wait for the sheet 233 to wait at a medium standby position where the conveyance sensor 225 is provided and not to pass between the photosensitive drum 300 and the transfer roller 304. 232 is controlled. Further, at the medium passing distance 505, the medium transport control unit 406 passes the sheet between the photosensitive drum 300 and the transfer roller 304 without applying the transfer bias to the transfer roller 304 by the image formation control unit 406. At 405, the conveyor belt 232 is controlled.

  In the printing apparatus of the present invention, the receiving unit 401 receives the print data, and the receiving unit 401 analyzes the print data to determine the color toner and the image forming units 226, 227, 228, and 229 used for the printing. The Then, based on the color of the toner used for printing determined by the receiving unit 401 by the medium print management unit 403, the printing apparatus is located on the most upstream side in the transport direction of the paper 233 among the image forming units to be used. A transport distance by which the sheet 233 is transported until reaching a certain image forming unit is obtained.

  As shown in FIG. 1, the distance between the image forming units 226, 227, 228, and 229 is 80 mm, and the distance from the conveyance sensor 225, which is the starting point of the conveyance distance, to the image forming unit 226 having black toner is 70 mm. . At this time, when the image forming unit on the most upstream side among the image forming units to be used is the image forming unit 226 having black toner, the transport distance is 70 mm, and the image forming unit 227 having yellow toner is used. In this case, the transport distance is 150 mm, the transport distance in the case of the image forming unit 228 having magenta toner is 230 mm, and the transport distance in the case of the image forming unit 229 having cyan toner is 310 mm. Hereinafter, although it demonstrates using these conveyance distances, this invention is not limited to this.

  Then, the medium print management unit 403 uses the transport distance and the distance that an arbitrary portion of the surface of the photosensitive drum 300 corresponding to a predetermined rotation amount required for stabilizing the surface potential of the photosensitive drum 300 moves. Compare with a certain moving distance. Since the moving distance of the photosensitive drum 300 required until the surface potential of the photosensitive drum 300 is stabilized is 219 mm as described above, this moving distance is compared with the above-described transport distance.

  The medium print management unit 403 calculates a difference between the movement distance and the conveyance distance from the above-described movement distance and conveyance distance. For example, when the image forming unit 226 is the most upstream among the image forming units to be used, the difference between the moving distance and the transport distance is 219 mm−70 mm = 149 mm, and the moving distance is longer. When the image forming unit 227 is the most upstream among the image forming units to be used, the difference between the moving distance and the conveying distance is 219 mm−150 mm = 69 mm, and the moving distance is longer. When the image forming unit 228 is the most upstream among the image forming units to be used, the difference between the moving distance and the transport distance is 219 mm−230 mm = −11 mm, and the transport distance is longer. When the image forming unit 229 is the most upstream among the image forming units to be used, the difference between the moving distance and the transport distance is 219 mm−310 mm = −91 mm, and the transport distance is longer.

  When the conveyance distance is shorter than the movement distance, the medium print management unit 403 notifies the controller unit 402 to stop the sheet 233 until the movement distance of the photosensitive drum 300 stabilizes the surface potential of the photosensitive drum 300. To do. In order to stabilize the surface potential of the photosensitive drum 300, for example, it is necessary to rotate it by 219 mm. Therefore, it is necessary to rotate only the difference between the moving distance and the conveying distance described above. The medium print management unit 403 counts this with a print prohibition counter. When the printing prohibition counter recognizes that an arbitrary position on the surface of the photosensitive drum 300 has moved 149 mm, which is the difference between the movement distance and the conveyance distance, the printing permission flag is turned on. When the print permission flag is turned on, the medium print management unit 403 notifies the controller unit 402 to that effect and notifies the start of printing by starting the conveyance of the sheet 233.

  Further, when the transport distance is longer than the moving distance, the medium print management unit 403 does not need to stop the paper 233 because the surface potential of the photosensitive drum 300 is stabilized while the paper 233 is transported. . Therefore, the print permission flag is turned on without counting by the print prohibition counter. When the print permission flag is turned on, the medium print management unit 403 notifies the controller unit 402 to that effect and notifies the start of printing by starting the conveyance of the sheet 233. At this time, no transfer bias is applied to the transfer roller 304 of the unused image forming unit.

  5 and 6 are time charts when printing is performed on a sheet by the printing apparatus of the present invention. FIG. 5 is a time chart when the printing apparatus receives print data for printing using toner of all four colors of black (K), yellow (Y), magenta (M), and cyan (C). FIG. 6 is a time chart when printing data is received using two color toners of magenta (M) and cyan (C).

  For example, when print data for printing using four color toners is received, as shown in FIG. 1, the image forming unit at the most upstream side in the conveyance direction of the paper 233 is a toner image with black (K) toner. Is an image forming unit 226. When print data for printing using four color toners is received, the paper 233 is transported by the paper feed operation by the paper feed control unit 404 and the transport operation by the medium transport control unit 405 as shown in FIG. Transport to sensor 225. At this time, the driving motor for rotating the photosensitive drum 300 is driven, and charging of the photosensitive drum 300 is started.

  In this print data, since the image forming units 226, 227, 228, and 229 having four color toners are used, the transport distance is 70 mm. Therefore, the medium print management unit 403 determines that the movement distance is longer when the conveyance distance and the movement distance are compared. At this time, the rotation amount of the photosensitive drum 300 is counted by the print prohibition counter. Then, the medium print management unit 403 causes the controller unit 402 to stop the sheet 233 by the conveyance sensor 225 by the medium conveyance control unit 405 until the print inhibition counter recognizes that the surface of the photosensitive drum 300 moves 149 mm. Give instructions. At this time, as shown in a region W1 in FIG. 5, a waiting time is generated until the print prohibition counter recognizes that the photosensitive drum 300 moves 149 mm.

  When the print prohibition counter recognizes that the photosensitive drum 300 has moved 149 mm, the print permission flag is turned on, the conveyance of the sheet 233 is resumed, and the controller unit 402 is instructed to start printing. Upon receiving the instruction, the controller unit 402 controls each control unit. The medium conveyance control unit 405 starts conveying the sheet 233 again. Then, the image formation control unit 406 applies the transfer bias of each image forming unit to the transfer roller 304 in accordance with the conveyance timing of the paper 233, and transfers the four color toner images onto the paper 233. In the case of print data for printing using these four color toners, the transfer bias to the transfer rollers 304 of all the image forming units is started after the drive motor rotates and charging of the photosensitive drum 300 is started. The time until the application is stopped is defined as time T1.

  Further, for example, when print data for printing using two color toners is received, the image forming unit on the most upstream side in the transport direction of the paper 233 is black (M) toner as shown in FIG. An image forming unit 228 forms a toner image. When print data for printing using two color toners is received, the paper 233 is transported by the paper feed operation by the paper feed control unit 404 and the transport operation by the medium transport control unit 405 as shown in FIG. Transport to sensor 225. At this time, the driving motor for rotating the photosensitive drum 300 is driven, and charging of the photosensitive drum 300 is started.

  In this print data, since the image forming units 228 and 229 having two colors of toner are used, the transport distance is 230 mm. Therefore, the medium print management unit 403 determines that the transport distance is shorter when the transport distance is compared with the movement distance. At this time, the rotation amount of the photosensitive drum 300 is not counted by the print prohibition counter, and the print permission flag is turned on. At this time, there is no waiting time until the surface potential of the photosensitive drum 300 is stabilized by the print prohibition counter as in the region W2 in FIG.

  Since the print permission flag is on, the controller unit 402 is instructed to transport the paper 233 and start printing. Upon receiving the instruction, the controller unit 402 controls each control unit. The image forming control unit 406 applies a transfer bias to the transfer rollers 304 of the unused image forming units 226 and 227 that are upstream of the image forming unit 228 that is upstream most of the used image forming units. do not do. Then, the image formation control unit 406 applies the transfer bias of the image forming units 228 and 229 to be used to the transfer roller 304 in accordance with the conveyance timing of the paper 233 by the image formation control unit 406, and thus the two-color toner image. Is transferred onto the sheet 233. In the case of print data for printing using these two color toners, the transfer bias to the transfer rollers 304 of all the image forming units after the drive motor rotates and charging of the photosensitive drum 300 is started. The time until the application is stopped is defined as time T2. As a result, it is possible to form a two-color toner image without adhering the toner adhering to the photosensitive drum 300 of the unused image forming units 226 and 227 to the paper 233. In addition, the first print time is shorter than printing using four colors of toner.

  Here, an operation when printing is performed using the printing apparatus of the present invention will be described with reference to FIG. The receiving unit 401 of the printing apparatus according to the present invention stands by until print data is transmitted from the host computer connected via the interface connector 236 in step S001. When receiving the print data from the host computer, the receiving unit 401 analyzes the received print data, converts the print data into data that can form a toner image by the image forming units 226, 227, 228, and 229 of the printing apparatus and uses them. Determine the color of the toner. Then, the reception unit 401 passes the converted data and information on the color of the toner used for printing to the controller unit 402.

  When the controller unit 402 receives the data received from the receiving unit 401 and the toner color information to be used, the controller unit 402 instructs the sheet feeding control unit 404 to start feeding the sheet 233. Upon receiving the instruction, the paper feed control unit 404 starts feeding the paper 233 from the tray 221 in step S002. When the paper feed control unit 404 recognizes the detection of the paper 233 by the paper feed sensor 223, the paper feed control unit 404 recognizes that the paper feed has been completed and notifies the controller unit 402 of the completion of paper feed.

  In step S003, the controller unit 402 waits until printing preparation is completed. Upon receiving a paper feed completion notification from the paper feed control unit 404, the controller unit 402 determines that the preparation for printing has been completed. Then, after determining that the preparation for printing has been completed, the controller unit 402 passes the data converted from the print data to the image formation control unit 406. At this time, the controller unit 402 passes the toner color information used for printing to the medium print management unit 403.

  In step S004, the image formation control unit 406 confirms the current operation state of the image formation units 226, 227, 228, and 229, and confirms whether or not the first printing is performed.

  If it is not the first printing, that is, if it is in the operating state, the process proceeds to step S011, and printing is started.

  In the case of the first printing, that is, in the non-operating state, the image formation control unit 406 drives the drive motors (not shown) of the image forming units 226, 227, 228, and 229 in step S005, In accordance with the drive of the drive motor, bias control is started so as to apply a predetermined voltage to each member.

  In step S006, the medium print management unit 403 recognizes the image forming unit to be used from the color of the toner to be used for printing, and among the image forming units to be used, the medium print management unit 403 is most upstream in the conveyance direction of the paper 233. The image forming unit on the side is recognized. Then, as described above, the conveyance distance and the movement distance are compared.

  In step S006, if the transport distance is longer than the moving distance, the medium print management unit 403 turns on the print permission flag and proceeds to step S011, and the medium print management unit 403 controls the controller unit to start printing. An instruction is issued to 402.

  If the transport distance is shorter than the movement distance in step S006, the medium print management unit 403 counts the rotation amount of the photosensitive drum 300 by the print prohibition counter in step S007. Then, the medium print management unit 403 instructs the controller unit 402 to stop the conveyance of the sheet 233 at the medium standby position where the conveyance sensor 225 is provided. Upon receiving this instruction, the controller unit 402 issues an instruction to the medium conveyance control unit 405.

  Thereafter, the medium conveyance control unit 405 waits until the sheet 233 is conveyed to the conveyance sensor 225 in step S008. When the sheet 233 is conveyed to the conveyance sensor 225, the medium print management unit 403 instructs the controller unit 402 to stop the conveyance of the sheet 233 in step S009, and the medium conveyance control unit 405 controls the medium 233.

  In step S010, the medium print management unit 403 waits until the surface potential of the photosensitive drum 300 is stabilized. That is, as described above, the process waits until the movement distance (rotation amount) of an arbitrary portion of the surface of the photosensitive drum 300 counted by the print prohibition counter reaches the distance indicated by the difference between the conveyance distance and the movement distance. Then, the print permission flag is turned on, the process proceeds to step S011, and the medium print management unit 403 instructs the controller unit 402 to start printing.

  Upon receiving a print instruction, the controller unit 402 issues instructions to the medium conveyance control unit 405, the image formation control unit 406, and the discharge control unit 407, and starts printing. In step S011, upon receiving an instruction from the controller unit 402, the medium conveyance control unit 405 conveys the sheet 233 to the image forming units 226, 227, 228, and 229. Then, based on the data obtained by converting the print data received from the controller unit 402, the image formation control unit 406 forms a toner image of each color using an image forming unit of the toner color used for printing.

  In step S012, the image formation control unit 406 applies a transfer bias only to the transfer roller 304 of the image forming unit to be used, and transfers the toner image onto the conveyed paper sheet 233. The discharge control unit 407 conveys the paper 233 on which the toner image is transferred to the fixing unit 230, fixes the toner image, and discharges it to the outside of the apparatus main body 210 of the printing apparatus.

  The printing apparatus of the present invention determines the color of the toner to be used, and among the image forming units having the color toner, the transport distance by which the sheet 233 is transported until reaching the most upstream image forming unit; The moving distance of the surface of the photosensitive drum 300 corresponding to a predetermined rotation amount required for stabilizing the surface potential applied to the photosensitive drum 300 of the image forming unit is compared. When the transport distance is longer than the movement distance, the surface potential of the photosensitive drum 300 is stabilized while the paper 233 is transported, and therefore the paper 233 is not stopped at the medium standby position on the transport path. Thereby, there is no useless waiting time for transporting the sheet 233, and the first print time can be shortened.

[Embodiment 2]
As shown in FIG. 8, the printing apparatus described in the second embodiment has a configuration including a print start position determination unit 408 having a margin determination unit instead of the medium print management unit 403 of the first embodiment. is there. Hereinafter, the printing apparatus according to the second embodiment will be described, but the same members as those in the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

  FIG. 9 is a diagram illustrating the print start position and the length of the leading edge margin on the print medium. The sheet 233 printed based on the print data has a margin as shown in FIG. For example, when printing is performed based on print data that is printed from the top of the page, the margin is a minimum value, such as the page top margin length 601. On the other hand, when printing is performed based on print data that is printed from the middle of the page, the page leading margin length 602 increases. In the present invention, the leading edge of the page indicates one end on the leading side in the direction in which the sheet 233 is conveyed in the printing apparatus.

  The print data is analyzed when received by the receiving unit 401, as in the first embodiment. At this time, in the second embodiment, the color of the toner to be used is determined, and analysis is performed so as to measure the margin length at the top of the page of each color. The receiving unit 401 passes information on the color of the toner to be used and information on the margin length of the page head of each color to the controller unit 402, and the controller unit 402 receives the information on the margin length of the page head of each color. The data is transferred to the print start position determination unit 408.

  The print start position determination unit 408 has the same function as the medium print management unit 403 described in the first embodiment, and also functions as a margin determination unit. Then, the controller unit 402 receives information on the color of the toner to be used and information on the margin length at the top of the page for each color. The printing start position determination unit 408 is used for printing after the movement distance of the surface of the photosensitive drum 300 corresponding to a predetermined rotation amount required for stabilizing the surface potential and the paper 233 is fed. Of the image forming units to be used based on the color of the toner, the distance to the image forming unit that is the furthest upstream in the conveying direction of the sheet 233 is compared with the distance obtained by adding the length of the margin at the top of each color page. . Then, the print start position determination unit 408 passes the comparison result to the controller unit 402, and the controller unit 402 issues an instruction to each member based on the result. In the printing apparatus described in the second embodiment, the photosensitive drum 300 of the image forming unit having the color of the toner used for printing subtracts the margin length determined by the print start position determination unit 408 from the predetermined rotation amount. After the rotation amount is rotated, the sheet 233 is conveyed by the medium conveyance control unit 405 to the image forming unit having the color of the toner used for printing. That is, the medium conveyance control unit 405 conveys the margin length from the time required for the photosensitive drum 300 of the image forming unit having the toner color used for printing to rotate by a predetermined amount of rotation from the start of printing. After the time required for the time has been subtracted, the sheet 233 is conveyed to the image forming unit. Thereby, the first print time can be shortened.

  Here, a case where the margin length of each color is 0 mm and the margin length of each color is 100 mm will be described as an example, and the distance compared with the movement distance will be described. The distance that the sheet 233 is conveyed is the distance from the conveyance sensor 225 to each of the image forming units 226, 227, 228, and 229, as in the first embodiment. As shown in FIG. 1, an image having black toner is used. The distance for transporting the paper 233 to the forming unit 226 is 70 mm, the distance for transporting the paper 233 to the image forming unit 227 having yellow toner is 150 mm, and the distance to transport the paper 233 to the image forming unit 228 having magenta toner. Is 230 mm, and the distance for transporting the paper 233 to the image forming unit 229 having cyan toner is 310 mm.

  The margin length of each color is added to this distance. For example, when the margin length is 0 mm, the distance is the same as described above. On the other hand, when the margin length is 100 mm, 100 mm is added to the above-mentioned distance. This is a distance that is compared with the movement distance, and is a distance to a position where printing on the sheet 233 is started. Since the movement distance is the same as that of the first embodiment, the description thereof is omitted.

  The print start position determination unit 408 compares the movement distance and the distance obtained by adding the margin length to the distance to which the sheet 233 is conveyed, and calculates the difference. For example, among the image forming units that are used based on the color of toner used for printing after the paper 233 is fed, the image forming unit that is on the most upstream side in the transport direction of the paper 233 has an image having black toner. In the case of the forming unit 226, if the margin length is 100 mm, this difference is 219 mm−70 mm−100 mm = 49 mm in the image forming unit 226 having black toner, and the moving distance becomes longer. In the image forming unit 227 having yellow toner, 219 mm−150 mm−100 mm = −31 mm, and the moving distance becomes shorter. In the image forming unit 228 having magenta toner, 219 mm−230 mm−100 mm = −111 mm, and the moving distance becomes shorter. In the image forming unit 229 having cyan toner, 219 mm−310 mm−100 mm = −191 mm, and the moving distance becomes shorter.

  When the distance obtained by adding the margin length to the transport distance is shorter than the movement distance, the print start position determination unit 408 moves the sheet 233 until the movement distance of the photosensitive drum 300 stabilizes the surface potential of the photosensitive drum 300. The controller unit 402 is notified to stop. In order to stabilize the surface potential of the photosensitive drum 300, for example, it is necessary to rotate it by 219 mm. Therefore, it is necessary to rotate only the difference between the moving distance and the distance obtained by adding the margin length to the conveying distance. is there. The print start position determination unit 408 counts this with a print prohibition counter. When the printing prohibition counter recognizes that an arbitrary position on the surface of the photosensitive drum 300 has moved by 49 mm, which is the difference between the moving distance and the distance obtained by adding the margin length to the conveying distance, the printing permission flag is turned on. Become. When the print permission flag is turned on, the print start position determination unit 408 notifies the controller unit 402 of the fact and starts conveying the paper 233 to notify the start of printing.

  The print start position determination unit 408 stabilizes the surface potential of the photosensitive drum 300 while the sheet 233 is being conveyed when the distance obtained by adding the margin length to the conveyance distance is longer than the movement distance. There is no need to stop the sheet 233. Therefore, the print permission flag is turned on without counting by the print prohibition counter. When the print permission flag is turned on, the print start position determination unit 408 notifies the controller unit 402 of the fact and starts conveying the paper 233 to notify the start of printing. At this time, no transfer bias is applied to the transfer roller 304 of the unused image forming unit.

  10 and 11 are time charts when printing is performed on paper with the printing apparatus of the present invention. FIG. 10 is a time chart when the printing apparatus receives print data whose margin length of each color is 0 mm, and FIG. 11 is a time chart when print data whose margin length of each color is 100 mm is received. is there.

  For example, when the printing apparatus receives print data in which the margin length of each color is 0 mm, as shown in FIG. 10, the sheet is fed by the sheet feeding operation by the sheet feeding control unit 404 and the conveyance operation by the medium conveyance control unit 405. 233 conveys to the conveyance sensor 225. At this time, the driving motor for rotating the photosensitive drum 300 is driven, and charging of the photosensitive drum 300 is started.

  In this print data, since the margin length is 0 mm, the distance obtained by adding the margin length to the conveyance distance is the conveyance distance of 70 mm to the image forming unit 226 using the black toner. Therefore, the print start position determination unit 408 determines that the movement distance is longer when the movement distance is compared with the distance obtained by adding the margin length to the conveyance distance. At this time, the rotation amount of the photosensitive drum 300 is counted by the print prohibition counter. Then, the print start position determination unit 408 controls the controller unit 402 so that the medium conveyance control unit 405 causes the conveyance sensor 225 to stop the sheet 233 until the print inhibition counter recognizes that the surface of the photosensitive drum 300 moves 149 mm. Give instructions. At this time, as shown in a region W3 in FIG. 10, a waiting time is generated until the print prohibition counter recognizes that the photosensitive drum 300 moves 149 mm.

  When the print prohibition counter recognizes that the photosensitive drum 300 has moved 149 mm, the print permission flag is turned on, the conveyance of the sheet 233 is resumed, and the controller unit 402 is instructed to start printing. Upon receiving the instruction, the controller unit 402 controls each control unit. The medium conveyance control unit 405 starts conveying the sheet 233 again. Then, the image formation control unit 406 applies the transfer bias of each image forming unit to the transfer roller 304 in accordance with the conveyance timing of the paper 233, and transfers the four color toner images onto the paper 233. In the case of print data with a margin length of 0 mm, the drive motor rotates and charging of the photosensitive drum 300 is started until the application of the transfer bias to the transfer rollers 304 of all image forming units is stopped. Is time T4.

  Further, for example, when print data having a margin length of 100 mm is received, the sheet 233 is changed by the sheet feeding operation by the sheet feeding control unit 404 and the conveyance operation by the medium conveyance control unit 405 as shown in FIG. Transport to the transport sensor 225. At this time, the driving motor for rotating the photosensitive drum 300 is driven, and charging of the photosensitive drum 300 is started.

  In this print data, since the margin length is 100 mm, the margin length is added to the conveyance distance 70 mm to the image forming unit 226 using the black toner. 170 mm. Therefore, the print start position determination unit 408 determines that the movement distance is longer when the movement distance is compared with the distance obtained by adding the extra length to the conveyance distance. At this time, the rotation amount of the photosensitive drum 300 is counted by the print prohibition counter. Then, the print start position determination unit 408 controls the controller unit 402 so that the medium conveyance control unit 405 causes the conveyance sensor 225 to stop the sheet 233 until the print inhibition counter recognizes that the surface of the photosensitive drum 300 moves 49 mm. Give instructions. At this time, as shown in a region W4 in FIG. 11, a waiting time is generated until the print inhibition counter recognizes that the photosensitive drum 300 has moved by 49 mm.

  When the print prohibition counter recognizes that the photosensitive drum 300 has moved by 49 mm, the print permission flag is turned on, the conveyance of the sheet 233 is resumed, and the controller unit 402 is instructed to start printing. Upon receiving the instruction, the controller unit 402 controls each control unit. The medium conveyance control unit 405 starts conveying the sheet 233 again. Then, the image formation control unit 406 applies the transfer bias of each image forming unit to the transfer roller 304 in accordance with the conveyance timing of the paper 233, and transfers the four color toner images onto the paper 233. At this time, the image formation control unit 406 performs control so that the transfer bias is not applied to the portion of the transfer roller 304 corresponding to the margin of the sheet 233 as shown in FIG. In the case of print data having a margin length of 100 mm, the application of the transfer bias to the transfer rollers 304 of all image forming units is stopped after the drive motor rotates and charging of the photosensitive drum 300 is started. The time until is T5. Comparing FIG. 10 and FIG. 11, the first print time is shortened by printing the print data having a margin length of 100 mm, compared with the case of printing the print data having no margin.

  Here, an operation when printing is performed using the printing apparatus of the present invention will be described with reference to FIG. In step S101, the receiving unit 401 of the printing apparatus according to the present invention stands by until print data is transmitted from the host computer connected via the interface connector 236. When receiving the print data from the host computer, the receiving unit 401 analyzes the received print data, converts the print data into data that can form a toner image by the image forming units 226, 227, 228, and 229 of the printing apparatus and uses them. The color of the toner is judged and the margin length of each color is measured. Then, the reception unit 401 passes the converted data and information on the margin length of each color to the controller unit 402.

  When the controller unit 402 receives the data received from the receiving unit 401, the information on the color of the toner to be used, and the information on the margin length of each color to be used, the controller unit 402 starts to feed the paper 233 to the paper feed control unit 404. Give instructions. Upon receiving the instruction, the paper feed control unit 404 starts feeding the paper 233 from the tray 221 in step S102. When the paper feed control unit 404 recognizes the detection of the paper 233 by the paper feed sensor 223, the paper feed control unit 404 recognizes that the paper feed has been completed and notifies the controller unit 402 of the completion of paper feed.

  In step S103, the controller unit 402 waits until printing preparation is completed. Upon receiving a paper feed completion notification from the paper feed control unit 404, the controller unit 402 determines that the preparation for printing has been completed. Then, after determining that the preparation for printing has been completed, the controller unit 402 passes the data converted from the print data to the image formation control unit 406. At this time, the controller unit 402 passes information on the color of the toner to be used and information on the margin length of each color to the print start position determination unit 408.

  In step S <b> 104, the image formation control unit 406 confirms the current operation state of the image formation units 226, 227, 228, and 229 and confirms whether or not the first printing is performed.

  If it is not the first printing, that is, if it is in an operating state, the process proceeds to step S111 and printing is started.

  In the case of printing the first sheet, that is, in the non-operating state, the image formation control unit 406 drives drive motors (not shown) of the image forming units 226, 227, 228, and 229 in step S105, In accordance with the drive of the drive motor, bias control is started so as to apply a predetermined voltage to each member.

  In step S106, the print start position determination unit 408 recognizes the image forming unit to be used from the color of the toner to be used for printing, and among the image forming units to be used, the print start position determination unit 408 Recognize the upstream image forming unit. Then, as described above, the distance obtained by adding the margin length to the transport distance is compared with the movement distance.

  If the distance obtained by adding the margin length to the transport distance is longer than the movement distance in step S106, the print start position determination unit 408 turns on the print permission flag, proceeds to step S111, and proceeds to step S111. Instructs the controller unit 402 to start printing.

  In step S106, when the distance obtained by adding the margin length to the transport distance is shorter than the movement distance, the print start position determination unit 408 counts the rotation amount of the photosensitive drum 300 by the print prohibition counter in step S107. Then, the print start position determination unit 408 instructs the controller unit 402 to stop the conveyance of the sheet 233 at the medium standby position where the conveyance sensor 225 is provided. Upon receiving this instruction, the controller unit 402 issues an instruction to the medium conveyance control unit 405.

  Thereafter, the medium conveyance control unit 405 waits until the sheet 233 is conveyed to the conveyance sensor 225 in step S108. When the sheet 233 is conveyed to the conveyance sensor 225, the print start position determination unit 408 instructs the controller unit 402 to stop the conveyance of the sheet 233 in step S109, and the medium conveyance control unit 405 performs control. .

  In step S110, the print start position determination unit 408 waits until the surface potential of the photosensitive drum 300 is stabilized. That is, as described above, the movement distance (rotation amount) of an arbitrary portion of the surface of the photosensitive drum 300 counted by the print prohibition counter is the difference between the movement distance and the distance obtained by adding the margin length to the conveyance distance. In step S111, the print start position determination unit 408 instructs the controller unit 402 to start printing.

  Upon receiving a print instruction, the controller unit 402 issues instructions to the medium conveyance control unit 405, the image formation control unit 406, and the discharge control unit 407, and starts printing. In step S <b> 111, the medium conveyance control unit 405 that has received an instruction from the controller unit 402 conveys the sheet 233 to the image forming units 226, 227, 228, and 229. Then, based on the data obtained by converting the print data received from the controller unit 402, the image formation control unit 406 forms a toner image of each color using an image forming unit of the toner color used for printing.

  In step S <b> 112, the image formation control unit 406 applies a transfer bias only to the transfer roller 304 of the image forming unit to be used, and transfers the toner image onto the conveyed paper sheet 233. The discharge control unit 407 conveys the paper 233 on which the toner image is transferred to the fixing unit 230, fixes the toner image, and discharges it to the outside of the apparatus main body 210 of the printing apparatus.

  The printing apparatus of the present invention measures the length of the margin of each color of the page, and the margin length is equal to the conveyance distance to which the sheet 233 is conveyed until reaching the most upstream image forming unit among the image forming units to be used. The distance plus the distance is compared with the moving distance of the surface of the photosensitive drum 300 corresponding to a predetermined amount of rotation required to stabilize the surface potential applied to the photosensitive drum 300 of the image forming unit. If the distance obtained by adding the margin length to the conveyance distance is longer than the movement distance, the surface potential of the photosensitive drum 300 is stabilized while the sheet 233 is being conveyed. Do not stop at the standby position. Thereby, there is no useless waiting time for transporting the sheet 233, and the first print time can be shortened. Further, even when the distance obtained by adding the margin length to the conveyance distance is shorter than the movement distance, the conveyance waiting time of the sheet 233 can be shortened by the margin length.

  In the first embodiment and the second embodiment, an example in which the sheet 233 is fed from the tray 221 is described. However, for example, the sheet 233 is fed from all the sheet feeding trays such as the multipurpose tray 222. In this case, similar control is possible. Even when the control is performed such that the second transfer sheet 233 is kept in a standby state and the photosensitive drum 300 is temporarily stopped, the same control is performed when the photosensitive drum 300 is restarted. Is possible. In this case, the same effect can be obtained not only by the tray 221 but also by paper feeding from the duplex printing apparatus.

1 is a diagram illustrating a configuration of a printing apparatus according to the present invention described in Embodiment 1. FIG. FIG. 2 is a diagram illustrating a configuration of an image forming unit of the printing apparatus according to the present invention described in the first embodiment. FIG. 2 is a control block diagram of the printing apparatus according to the present invention described in the first embodiment. FIG. 3 is a diagram illustrating a charged state of toner on the surface of the photosensitive drum of the printing apparatus of the present invention described in the first embodiment. 4 is a time chart when print data for printing using four color toners is received in the printing apparatus of the present invention described in the first embodiment. 6 is a time chart when print data for printing using two colors of toner is received in the printing apparatus of the present invention described in the first embodiment. FIG. 3 is a flowchart showing the operation of the printing apparatus of the present invention described in the first embodiment. FIG. 6 is a control block diagram of a printing apparatus according to the present invention described in a second embodiment. FIG. 10 is a diagram for explaining a margin of a sheet used in the printing apparatus of the present invention described in the second embodiment. 7 is a time chart when print data with a margin length of 0 mm is received in the printing apparatus of the present invention described in the second embodiment. 6 is a time chart when printing data having a margin length of 100 mm is received in the printing apparatus of the present invention described in the second embodiment. FIG. 10 is a flowchart showing the operation of the printing apparatus of the present invention described in the second embodiment.

Explanation of symbols

210 apparatus main body 221 tray 222 multi-purpose tray 223, 224 paper feed sensor 224 paper feed sensor 225 transport sensor 226, 227, 228, 229 image forming unit 230 fixing unit 231 discharge sensor 232 transport belt 233 paper 235 transport path 236 interface connector 300 Photosensitive drum 301 Charging roller 302 Head 303 Developing roller 304 Transfer roller 305 Toner supply roller 306 Toner cartridge 401 Reception unit 402 Controller unit 403 Medium print management unit 404 Paper feed control unit 405 Medium transport control unit 406 Image formation control unit 407 Ejection control Part 408 printing start position judgment part

Claims (4)

In a printing apparatus that prints by attaching a developer image based on print data to the print medium by a plurality of image forming units arranged in the conveyance direction of the print medium,
A photoreceptor disposed in each of the image forming units;
A potential controller that controls the potential applied to the outer peripheral surface of each of the photoreceptors;
A rotation amount management unit for managing a rotation amount necessary for the potential of the outer peripheral surface of each of the photoconductors to be a potential at which the developer image can be formed;
A drive unit that rotationally drives the photoreceptor of each of the image forming units;
A medium conveyance control unit for controlling conveyance of the print medium;
A print color determination unit that determines the color of the developer used for printing based on the print data;
The medium conveyance control unit is configured to perform the photosensitivity based on the rotation amount necessary for the photoconductor of the image forming unit of the color used for printing determined by the print color determination unit managed by the rotation amount management unit. A printing apparatus that transports the print medium to the image forming unit of a color used for printing after the body has rotated the rotation amount. A medium position determining unit that determines a position of the print medium on a conveyance path of the print medium;
The medium conveyance control unit is configured such that a distance from the position of the print medium determined by the medium position determination unit to the image forming unit of the color used for printing determined by the print color determination unit is the rotation amount. 2. The printing apparatus according to claim 1, wherein when the movement distance of the corresponding outer peripheral surface of the photoconductor is shorter, the conveyance speed of the print medium is decreased. A margin determination unit that determines a margin range in which printing is not performed from the top in the transport direction of the print medium based on the print data;
The medium conveyance control unit is configured to perform the printing based on the rotation amount necessary for the photosensitive member of the image forming unit of the color used for printing determined by the print color determination unit managed by the rotation amount management unit. The printing apparatus according to claim 1, wherein the printing medium is conveyed to the image forming unit of a color used for printing after being rotated by a rotation amount obtained by subtracting an amount corresponding to the margin range of the medium. A medium position determining unit that determines a position of the print medium on a conveyance path of the print medium;
The medium conveyance control unit is configured such that a distance from the position of the print medium determined by the medium position determination unit to the image forming unit of the color used for printing determined by the print color determination unit is the rotation amount. The transport speed of the print medium is reduced when the distance is shorter than a distance obtained by subtracting a length corresponding to the margin range of the print medium from a movement distance of the outer peripheral surface of the corresponding photoconductor. The printing apparatus according to 3.