JP2007178760A - Image printing device, image printing method and program therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain the deterioration of a toner image forming surface and also to surely peel a printing medium from the toner image forming surface. <P>SOLUTION: When margin amount R on the leading edge side of paper P is smaller than necessary margin amount Rth in secondary transfer (S108), a separation pawl is brought into contact with a transfer belt when contact start timing T comes (S112). Thus, the leading edge of the paper P is easily peeled from the transfer belt by the separation pawl. Meanwhile, after the leading edge of the paper P is peeled from the transfer belt (S114), the separation pawl is separated from the transfer belt (S116). Thus, the separation pawl is prevented from wearing or damaging the transfer belt. By bringing the separation pawl into contact with the transfer belt only when judging it as necessary based on printing data, the paper P is surely peeled from the transfer belt while restraining the deterioration of the transfer belt. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image printing apparatus, an image printing method, and a program therefor.

Conventionally, when a toner image formed on the surface of a photoreceptor or a transfer belt is transferred to a sheet, the sheet after the transfer remains in close contact with the surface of the photoreceptor (hereinafter referred to as a toner image forming surface). 2. Description of the Related Art Image printing apparatuses having a mechanism for preventing such a problem are known. For example, in the image printing apparatus disclosed in Patent Document 1, a separation claw with a leading end in contact with the toner image forming surface is provided in the vicinity of the toner image forming surface and on the paper carry-out direction side. Therefore, even when the leading edge of the paper remains stuck to the toner image forming surface, the leading edge of the separation claw enters between the paper and the toner image forming surface, thereby peeling the paper from the toner image forming surface. Can do.
JP 2002-91178 A

  However, in Patent Document 1 described above, since the toner image forming surface and the separation claw are always in contact with each other, there is a problem that the toner image forming surface is easily deteriorated due to wear due to contact with the separation claw. It is also conceivable to use a non-contact type separation claw in which the tip of the separation claw is slightly lifted from the toner image forming surface. For example, the toner adheres to the edge of the paper as in borderless printing. In this case, the leading edge of the paper is likely to be in close contact with the toner image forming surface, and the leading edge of the paper is not easily caught by the separation claw. For this reason, it cannot be said that the non-contact type separation claw reliably peels the paper from the toner image forming surface.

  The present invention has been made to solve such a problem, and an image printing apparatus and an image printing which can suppress the deterioration of the toner image forming surface and can reliably peel the print medium from the toner image forming surface. It is an object to provide a method and a program thereof.

  The present invention adopts the following means in order to achieve the above-mentioned object.

That is, the image printing apparatus of the present invention is
An image printing apparatus for printing an image on a print medium,
A toner image forming surface on which a toner image is formed;
Transfer means for transferring the toner image to the print medium by sending out the print medium while pressing the print medium against the toner image forming surface;
A first posture in which the leading end of the print medium fed out while being pressed against the toner image forming surface by the transfer means comes into contact with a position where it can be separated from the toner image forming surface, and a second posture separated from the toner image forming surface. A peeling member capable of taking a posture;
Positioning means for positioning the peeling member in the first posture or the second posture;
It is equipped with.

  In this image printing apparatus, when the print medium is fed while being pressed against the toner image forming surface by the transfer means, the positioning member is operated to position the peeling member in the first posture, so that the leading edge of the print medium is moved by the peeling member. It peels easily from the toner image forming surface. On the other hand, if the positioning member is operated to position the peeling member in the second posture after the leading edge of the printing medium is peeled off from the toner image forming surface, the peeling member does not wear or damage the toner image forming surface. . In this way, by bringing the peeling member into contact with the toner image forming surface only when necessary, the deterioration of the toner image forming surface can be suppressed compared with the case where the peeling member is always kept in contact with the toner image forming surface, and the product life is shortened. Can be long. Further, if the peeling member is brought into contact with the toner image forming surface, the peeling member is likely to enter between the toner image forming surface and the printing medium as compared with a case where the peeling member and the toner image forming surface are not in contact with each other. The print medium can be reliably peeled off from the toner image forming surface.

  The image printing apparatus of the present invention further controls the positioning means so that the peeling member takes the first posture when the printing medium is sent out while being pressed against the toner forming surface by the transfer means, After the leading edge of the print medium is peeled off from the toner image forming surface, it may be provided with a control means for performing positioning control for controlling the positioning means so that the peeling member takes the second posture. In this way, the peeling member can be brought into contact with the toner image forming surface only when necessary without requiring a complicated operation by the user.

  The image printing apparatus of the present invention further includes position detection means for detecting the position of the print medium, and the control means forms the toner image on the print medium by the transfer means when executing the positioning control. When the sheet is fed while being pressed against the surface, the timing for changing the peeling member from the second position to the first position is determined based on the position of the print medium detected by the position detecting unit, and the determined timing The positioning means may be controlled so that the peeling member takes the first posture. In this way, the timing for bringing the peeling member into contact with the toner image forming surface is set based on the position of the printing medium, so when the printing medium is sent to a position where the separation between the printing medium and the toner image forming surface is necessary. The peeling member can be brought into contact with the toner image forming surface.

  The image printing apparatus of the present invention further includes a peeling detection unit that detects whether or not the leading edge of the printing medium is peeled off from the toner image forming surface, and the control unit performs the positioning control. The positioning means may be controlled so that the peeling member takes the second posture after the peeling detection means detects that the leading edge of the print medium has been peeled off from the toner image forming surface. In this way, it is possible to accurately grasp that the leading edge of the print medium has been peeled off from the toner image forming surface, and the peeling member is not brought into contact with the toner image forming surface more than necessary.

  In the image printing apparatus according to the aspect of the invention, when the control unit performs the positioning control, the front end of the print medium forms the toner image on the basis of a time elapsed after the peeling member takes the first posture. It is determined whether or not the peeling member has peeled off from the surface, and after determining that the leading edge of the print medium has peeled off from the toner image forming surface, the positioning member is controlled so that the peeling member takes the second posture. It is good. In this way, it is possible to grasp that the leading edge of the printing medium has been peeled off from the toner image forming surface without providing a new detection means for detecting that the leading edge of the printing medium has been peeled off from the toner image forming surface. it can.

  The image printing apparatus of the present invention further includes an input unit for inputting image data, and the control unit determines whether or not to execute the positioning control based on the image data input to the input unit. It is good. The ease with which the print medium adheres to the toner image forming surface varies depending on the state of the image (for example, an image pattern) based on the image data. Therefore, it is preferable to bring the peeling member into contact with the toner image forming surface only when it is determined that the print medium is difficult to peel from the toner image forming surface based on the image data.

  In the image printing apparatus of the present invention having the input unit as described above, the control unit grasps a margin amount in a predetermined area on the leading end side of the print medium from the image data, and the grasped margin amount is a predetermined margin amount. The positioning control may be executed when the number is less. In this way, the print medium can be reliably peeled from the toner image forming surface even when the margin of the front end region of the print medium is small, and deterioration of the toner image forming surface can be effectively suppressed. . Here, the predetermined margin amount is set, for example, by an experiment in advance as a lower limit value of the margin amount necessary for peeling the front end of the printing medium sent out by the transfer unit from the toner image forming surface without using a peeling member. It is good. The predetermined area may be set as appropriate. At this time, the control means may execute the positioning control at the time of marginless printing in which the margin amount is very small or substantially zero. In borderless printing, the toner adheres to the entire surface of the print medium, so that compared to printing with margins on the edge of the print medium, the leading edge of the print medium is more likely to be in close contact with the toner image forming surface during transfer. Significant to apply.

  In the image printing apparatus of the present invention including an input unit, the control unit detects the degree of toner adhesion in a predetermined region on the front end side of the print medium from the image data, and the detected degree of toner adhesion is detected. The positioning control may be executed when it is larger than a predetermined degree. In this way, the print medium can be reliably peeled from the toner image forming surface even when the degree of toner adhesion at the leading edge region of the print medium is large, and the deterioration of the toner image forming surface can be effectively prevented. Can be suppressed. Here, the predetermined degree is, for example, an experiment in advance as a lower limit value of the degree of adhesion of the toner that can peel the front end of the print medium sent out by the transfer unit from the toner image forming surface without using a peeling member. You may set by. The predetermined area may be set as appropriate.

  In the image printing apparatus of the present invention, the control means may determine whether or not to execute the positioning control based on a type of the print medium. The ease with which the print medium adheres to the toner image forming surface varies depending on the type of the print medium (for example, the properties and materials of the print medium surface such as flatness and wetness, the thickness and size of the print medium, etc.). . Therefore, it is preferable that the peeling member is brought into contact with the toner image forming surface only when it is determined that the printing medium is difficult to peel from the toner image forming surface based on the type of the printing medium. At this time, the control means may execute the positioning control when the print medium is thinner than a predetermined thickness. In this way, even when the print medium is thin, the print medium can be reliably peeled off from the toner image forming surface, and deterioration of the toner image forming surface can be effectively suppressed. Here, the predetermined thickness is, for example, an experiment in advance as a lower limit value of the thickness of the print medium that can be peeled from the toner image forming surface without using a peeling member, without using a peeling member. You may set by.

The image printing method of the present invention includes:
An image printing method by computer software for printing an image on a print medium,
A first posture in which a front end of a print medium fed out while being pressed against the toner image forming surface of the toner image forming surface on which the toner image is formed contacts a position where the toner image can be peeled from the toner image forming surface; Using a peeling member capable of taking a second posture separated from the forming surface, and positioning means for positioning the peeling member in the first posture or the second posture,
(A) transferring the toner image to the print medium by sending the print medium while pressing the print medium against the toner image forming surface;
(B) the step of causing the peeling member to take the first posture by the positioning means when the printing medium is sent out while being pressed against the toner image forming surface in the step (a);
(C) after the leading edge of the printing medium is peeled off from the toner image forming surface in the step (b), the step of causing the peeling member to take the second posture by the positioning means;
Is included.

  In this image printing method, when the printing medium is sent out while being pressed against the toner image forming surface by the transfer means, the positioning member is operated to position the peeling member in the first posture. It peels easily from the toner image forming surface. On the other hand, after the leading edge of the print medium is peeled off from the toner image forming surface, the peeling member wears or damages the toner image forming surface because the positioning member is operated to position the peeling member in the second posture. There is no. In this way, by bringing the peeling member into contact with the toner image forming surface only when necessary, the deterioration of the toner image forming surface can be suppressed compared with the case where the peeling member is always kept in contact with the toner image forming surface, and the product life is shortened. Can be long. Further, if the peeling member is brought into contact with the toner image forming surface, the peeling member is likely to enter between the toner image forming surface and the printing medium as compared with a case where the peeling member and the toner image forming surface are not in contact with each other. The print medium can be reliably peeled off from the toner image forming surface. In addition, you may add the step which implement | achieves the function of any of the image printing apparatus mentioned above to the image printing method of this invention.

  The image printing program of the present invention is a program for causing one or more computers to execute each step of the above-described image printing method. This program may be recorded on a computer-readable recording medium (for example, hard disk, ROM, FD, CD, DVD, etc.), or from a computer via a transmission medium (communication network such as the Internet or LAN). It may be distributed to another computer, or may be exchanged in any other form. If this program is executed by a single computer or each step is shared and executed by a plurality of computers, the same effect as the above-described image printing method can be obtained.

  1 is a block diagram showing a schematic configuration of a color laser printer 10 according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing a schematic configuration of a printer mechanism 31 of the color laser printer 10, and FIG. 3 is a secondary transfer unit. 6 is a configuration diagram showing a schematic configuration of No. 67. FIG.

  As shown in FIG. 1, the color laser printer 10 of this embodiment includes a controller 20 that controls the entire apparatus, an electrophotographic printer mechanism 31, and a printer ASIC 32 that controls the printer mechanism 31. A printer unit 30; a secondary transfer unit 67 that transfers a toner image onto the paper P in the printer mechanism 31; and a separation claw 70 that is provided near the secondary transfer unit 67 and separates the paper P from the secondary transfer unit 67. And an operation panel 44 for inputting instructions by the user and displaying various information. Note that “ASIC” is an abbreviation for Application Specific Integrated Circuit.

  The controller 20 is configured as a microprocessor centered on the CPU 21, and is electrically rewritable with a ROM 22 that stores various processing programs and a RAM 23 that temporarily stores data and stores data. A flash memory 24 that retains data even when the power is turned off and a job memory 25 that stores a print job are provided. The controller 20 is electrically connected to the printer ASIC 32, the operation panel 44, the first and second detection sensors 80 a and 80 b, and the solenoid 71 that moves the separation claw 70 via the bus 27, and print command signals to the printer ASIC 32 and the like. A display command signal to the operation panel 44 and a control signal to the solenoid 71 are output, a printing operation signal from the printer ASIC 32, various command signals from the operation panel 44, and detection signals from the first and second detection sensors 80a and 80b. Enter. The controller 20 also exchanges signals with a plurality of computers 51 to 53 connected to a network (for example, a telecommunication network such as a local area network) via the network board 27. That is, the controller 20 inputs a print job and various command signals from each of the computers 51 to 53 and outputs status information of the print job being processed to the computers 51 to 53 that are the transmission source of the print job.

  The printer unit 30 includes a printer mechanism 31 and a printer ASIC 32. As shown in FIG. 2, the printer mechanism 31 is configured as a full-color electrophotographic printer mechanism that employs a single photoreceptor system and an intermediate transfer system, and has cyan (C) and magenta (C) on the charged surface. M), yellow (Y), black (K), and a photosensitive member 63 on which an electrostatic latent image of an image for each color separated into four colors is formed by an exposure device 62, and toner cartridges 40C, 40M, The toner 61 of each color supplied from 40Y and 40K is attached to the electrostatic latent image formed on the photosensitive member 63 and developed as a toner image, and primary transfer is performed so that the developed toner images of each color are superimposed. A secondary belt that secondary-transfers a four-color toner image formed on the transfer belt 64 to a transfer belt 64 as an intermediate transfer member and a sheet P transported from a sheet cassette 65 by a transport unit 66. A shooting unit 67, and a fixing unit 68 for melting and fixing the toner images of four colors have been transferred onto the sheet P to the paper P, a paper discharge tray 69 for storing the sheet discharged P. Among these, the developing device 61 is rotated so that the mounted toner cartridges 40C, 40M, 40Y, and 40K face the photoconductor 63, respectively. The exposure device 62 exposes the photoconductor 63 with a laser beam scanned by a polygon mirror that is rotationally driven by a motor to form an electrostatic latent image. On the other hand, the printer ASIC 32 is an IC chip having a function of controlling the printer mechanism 31, and development data obtained by developing a print job stored in the job memory 25 into a bitmap image for each page is printed on the paper P. The printer mechanism 31 is controlled.

  As shown in FIG. 3, the secondary transfer unit 67 includes a belt roller 81 whose outer periphery is covered with rubber and over which the transfer belt 64 is stretched, and an outer periphery which is covered with rubber harder than the belt roller 81 and passes through the transfer belt 64. The conductive secondary transfer roller 82 is in pressure contact with the belt roller 81. Among them, the belt roller 81 rotates the drive rotor 60 (see FIG. 2) spanned around the transfer belt 64 by using a motor (not shown) so that the transfer belt 64 circulates. The driven rotation is synchronized. When the paper P is transported to the secondary transfer unit 67 by the transport unit 66, the transfer belt 64 circulates by driving the drive rotor 60. As a result, the belt roller 81 and the secondary transfer roller 82 rotate to convey the paper P downstream while sandwiching the paper P. At this time, when the toner image on the transfer belt 64 and the surface of the paper P overlap with each other, the paper P is fed to the secondary transfer unit 67 and a DC voltage is applied to the secondary transfer roller 82, so that the toner image is formed on the transfer belt 64. The transferred toner image is transferred onto the paper P. Since the secondary transfer roller 82 is covered with rubber harder than the belt roller 81, when the leading edge of the paper P is not in close contact with the transfer belt 64, the belt is between the belt roller 81 and the secondary transfer roller 82. Due to the generated nip pressure, the paper P is peeled off from the transfer belt 64 and carried out of the secondary transfer unit 67. Further, a first detection sensor 80a and a second detection sensor 80b for detecting the presence or absence of the paper P are arranged in the vicinity of the upstream side and the downstream side of the belt roller 81, respectively. The detection sensors 80a and 80b are contact type micro switch sensors, and output a detection signal when the leading end portion of the paper P passes through the detection sensors 80a and 80b.

  As shown in FIG. 3, the separation claw 70 is slightly smaller than the position Q immediately after the sheet P is released from the pressure contact between the transfer belt 64 and the secondary transfer roller 82 among the positions facing the transfer belt 64. One is provided on the downstream side by a distance (for example, several millimeters to several centimeters) and at the center with respect to the width direction of the transfer belt 64. The separation claw 70 is a thin plate having a pointed end near the belt roller 81 and having elasticity, and is movable by a solenoid 71. That is, when the solenoid 71 is not energized, the separation claw 70 is separated from the transfer belt 64 by a small distance (for example, several mm), and when the solenoid 71 is energized, the separation claw 70 contacts the transfer belt 64.

  The operation panel 44 displays various input buttons 46 such as a numeric keypad and cursor keys capable of inputting an instruction from the user, characters and numbers associated with the key operation, and processing statuses in the controller 20 and the printer unit 30. Liquid crystal screen 45.

  Next, functions of the color laser printer 10 of the present embodiment configured as described above, particularly, a procedure for performing printing on the paper P will be described. When the CPU 21 of the controller 20 receives a print job from any of the computers 51 to 53 connected via the network, the print job is stored in the job memory 25 and a print command is output to the printer ASIC 32 of the printer unit 30. To do. When this print command is input, the printer ASIC 32 executes a print processing routine shown in FIG.

  When this print processing routine is started, the CPU 21 of the controller 20 first feeds paper from the paper cassette 65 by the transport unit 66 and starts transporting the paper P toward the secondary transfer unit 67 (step S100). Next, one page of the print job in the job memory 25 is developed into a bitmap image and separated into four colors of yellow, magenta, cyan, and black (step S102). Subsequently, after the surface of the photoconductor 63 is charged, an electrostatic latent image is formed on the surface of the photoconductor 63 by the exposure device 62 based on an image image of any one color (for example, yellow) among the color-separated image images. The yellow toner supplied from the toner cartridge 40Y is attached to the electrostatic latent image on the photoconductor 63 to develop the toner image, and the developed yellow toner image is primarily transferred to the transfer belt 64 (step S104). ). Thereafter, the developing device 61 is sequentially rotated, and charging, exposure, development, and primary transfer are performed in the same manner for the other three colors. When the primary transfer is completed for all colors, a four-color toner image is formed on the transfer belt 64 by sequentially superimposing the toner images of the respective colors.

  When the primary transfer is completed, the CPU 21 drives the drive motor 60 to circulate the transfer belt 64, and starts the secondary transfer of the superposed toner image on the transfer belt 64 to the paper P while transporting the paper P. (Step S106). Subsequently, it is determined whether or not the margin amount R in the leading end region of the paper P (for example, a region several centimeters from the leading end of the paper P) is smaller than the necessary margin amount Rth (step S108). Here, the margin amount R is determined from the information regarding the margin of the paper P included in the print data transmitted from the computers 51 to 53. The information regarding the margin is set depending on whether the margin amount is set or borderless printing is specified on the print instruction screen in which the user instructs printing. Further, the necessary margin amount Rth is a lower limit value of the margin amount necessary for peeling the leading edge of the paper P from the transfer belt 64 without using the separation claw 70 during the secondary transfer (for example, several millimeters from the leading edge of the paper P). (About several centimeters) is a value set in advance by experiments or the like. Note that the margin amount R is zero during borderless printing.

  When the margin amount R is smaller than the necessary margin amount Rth in step S108, the CPU 21 determines whether or not the contact start timing T for bringing the separation claw 70 into contact with the transfer belt 64 has been reached (step S110). This contact start timing T is set based on a detection signal from the first detection sensor 80a. That is, the time required for the leading edge of the paper P to reach the position Q (see FIG. 3) immediately after being released from the pressure contact between the belt roller 81 and the secondary transfer roller 82 after passing through the first detection sensor 80a is the conveyance time. Let t be the contact start timing T when the conveyance time t has elapsed after the detection signal is output from the first detection sensor 80a. In the present embodiment, the transport speed for transporting the paper P from the first detection sensor 80a to the position Q is substantially the same for printing one page. When the contact start timing T is not reached in step S110, the process waits until the contact start timing T is reached. When the leading edge of the paper P reaches the position Q and reaches the contact start timing T, the solenoid 71 is energized and separated. The claw 70 is brought into contact with the transfer belt 64 (step S112). That is, the separation claw 70 contacts the transfer belt 64 when the leading edge of the paper P reaches the position Q.

  Subsequently, the CPU 21 determines whether or not a detection signal from the second detection sensor 80b is input (step S114). When the detection signal is not yet input from the second detection sensor 80b, the separation claw 70 is transferred. Keep in contact with belt 64. As described above, when the detection signal is not output from the second detection sensor 80b, the leading edge of the sheet P is in close contact with the transfer belt 64 or the leading edge of the sheet P is not yet conveyed to the second detection sensor 80b. Is mentioned. On the other hand, when a detection signal is input from the second detection sensor 80b, it is determined that the leading edge of the sheet P has been peeled off from the transfer belt 64, the energization to the solenoid 71 is stopped, and the separation claw 70 is separated from the transfer belt 64. (Step S116).

  When the margin amount R is greater than or equal to the required margin amount Rth in step S108 or after the separation claw 70 is separated from the transfer belt 64 in step S116, the CPU 21 displays the four-color toner image secondarily transferred onto the paper P. It is melted and fixed by the fixing unit 68 (step S118), and the fixed paper P is discharged to the paper discharge tray 69 (step S120). Thereafter, it is determined whether or not there are pages to be printed (step S122). When there are pages to be printed, the process returns to step S100, and when there are no pages to be printed, this routine is terminated.

  Here, the correspondence between the components of the present embodiment and the components of the present invention will be clarified. The transfer belt 64 of the present embodiment corresponds to a toner image forming surface of the present invention, the secondary transfer unit 67 corresponds to a transfer unit, and the separation claw 70 corresponds to a peeling member. The solenoid 71 corresponds to the positioning means, the CPU 21 of the controller 20 corresponds to the control means, the first detection sensor 80a corresponds to the position detection means, the second detection means 80b corresponds to the peeling detection means, and the network board Reference numeral 27 corresponds to an input means. In this embodiment, an example of the image printing method of the present invention is also clarified by describing the operation of the color laser printer 10.

  According to the color laser printer 10 of the present embodiment described in detail above, the leading end of the sheet P is released from the pressure contact between the belt roller 81 and the secondary transfer roller 82 when there is not enough margin at the leading end of the sheet P. The separation claw 70 is brought into contact with the transfer belt 64 at a timing immediately after being performed. As a result, the leading edge of the separation claw 70 enters between the paper P and the transfer belt 64, so that the leading edge of the paper P is easily separated from the transfer belt 64 by the separation claw 70. When the position detection sensor 80b detects that the leading edge of the paper P is peeled off from the transfer belt 64, the separation claw 70 does not need to be in contact with the transfer belt 64 any more. 70 is separated. As a result, the separation claw 70 and the transfer belt 64 are not in contact with each other, so that the separation claw 70 does not wear or damage the transfer belt 64. In this way, by bringing the separation claw 70 into contact with the transfer belt 64 only when necessary, the deterioration of the transfer belt 64 can be suppressed and the product life can be extended compared to the case where the separation claw 70 is kept in contact with the transfer belt 64 at all times. can do. Further, if the separation claw 70 is brought into contact with the transfer belt 64, the leading end of the separation claw 70 can easily enter between the transfer belt 64 and the paper P, compared to the case where the separation claw 70 and the transfer belt 64 are not in contact with each other. Therefore, the paper P can be reliably peeled from the transfer belt 64.

  Further, since the operation of bringing the separation claw 70 into contact with or separating from the transfer belt 64 is performed by the CPU 21 energizing or de-energizing the solenoid 71, no complicated operation by the user is required.

  Further, since the timing at which the separation claw 70 is brought into contact with the transfer belt 64 is set based on the position of the paper P detected by the first detection sensor 80a, the paper is moved to a position where the separation between the paper P and the transfer belt 64 is necessary. The separation claw 70 can be brought into contact with the transfer belt 64 when P is sent out.

  Further, whether or not the leading edge of the paper P has been peeled off from the transfer belt 64 is determined based on the presence or absence of a detection signal from the second detection sensor 80b. be able to. Therefore, the separation claw 70 is not brought into contact with the transfer belt 64 more than necessary.

  Since the separation claw 70 is brought into contact with the transfer belt 64 when the margin amount R in the leading end region of the sheet P is smaller than the necessary margin amount Rth, the sheet P can be reliably peeled from the transfer belt 64. Further, when the margin amount R of the leading end region of the sheet P is equal to or larger than the necessary margin amount Rth, the separation claw 70 is not brought into contact with the transfer belt 64 even when the sheet P is peeled off from the transfer belt 64. Can be effectively suppressed.

  Further, when the margin amount R is zero, that is, borderless printing, the toner is attached to every corner of the paper P so that the leading edge of the paper P is easily adhered to the transfer belt 64. The sheet P can be reliably peeled from the transfer belt 64 by contacting with the sheet. Further, even if the toner is attached to a range substantially the same as or larger than the size of the paper P, the separation claw 64 is separated from the transfer belt 64 when the leading edge of the paper P is peeled off from the transfer belt 64. The separation claw 64 can be prevented from becoming dirty.

  It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that the present invention can be implemented in various modes as long as it belongs to the technical scope of the present invention.

  For example, in the print processing routine of the above-described embodiment, whether or not the separation claw 70 is brought into contact with the transfer belt 64 is determined based on the margin amount R based on the print data in step S106. At the same time, whether or not the separation claw 70 is brought into contact with the transfer belt 64 may be determined based on the degree of toner adhesion in a predetermined region on the leading end side of the paper P. For example, the print processing routine of FIG. 5 may be executed. In FIG. 5, the same processes as those in FIG. 4 are denoted by the same step numbers as those in FIG. When the print processing routine of FIG. 5 is started, the CPU 21 executes the processes of steps S100 to S106, and then, in the bitmap image of the page to be printed this time, a predetermined area (for example, the sheet P of the paper P). It is determined whether or not the number of dots S in the region of several centimeters from the front end side is larger than a predetermined number Sth (step S208). Here, the predetermined number Sth is a value set in advance by an experiment or the like as the upper limit value of the number of dots that can be peeled off from the transfer belt 64 without using the separation claw 70 at the time of secondary transfer. Then, the process of steps S110-S122 is performed and this routine is complete | finished. In this way, the separation claw 70 can be brought into contact with the transfer belt 64 when the paper P easily adheres to the transfer belt 64 based on the degree of toner adhesion.

  In the embodiment described above, whether or not the separation claw 70 is brought into contact with the transfer belt 64 may be determined according to the type of the paper P. Specifically, the print processing routine of FIG. 6 may be executed. In FIG. 6, the same processes as those in FIG. 4 are denoted by the same step numbers as in FIG. When the print processing routine of FIG. 6 is started, the CPU 21 first executes the processes of steps S100 to S108. When the margin amount R is greater than or equal to the required margin amount Rth in step S108, the type of the paper P currently being printed is determined (step S308). Here, the type of the paper P currently being printed is determined by reading out information on the type of the paper P included in the print data. This information is created based on the type of paper P selected on the print instruction screen for the user to instruct printing. In addition, the predetermined thin paper is a paper (for example, a trace paper) that has a small thickness and is easily adhered to the transfer belt 64. On the other hand, if the type of the paper P currently being printed is not a predetermined thin paper, the processing after step S118 is executed, and this routine is terminated. By doing so, the separation claw 70 can be brought into contact with the transfer belt 64 when the paper P is easily in close contact with the transfer belt 64 because the thickness of the paper P is thin. At this time, instead of or together with the thickness of the sheet P, the separation claw 70 is brought into contact with the transfer belt 64 based on the properties, material, size, etc. of the surface of the printing medium such as flatness and wetness. It may be determined whether or not to be performed.

  In the above-described embodiment, the separation claw 70 is separated from the transfer belt 64 when the detection signal from the second detection sensor 80b is input, but based on the time that has elapsed since the separation claw 70 was brought into contact with the transfer belt 64. The separation claw 70 may be separated from the transfer belt 64. In this way, it is possible to grasp that the leading edge of the paper P has been peeled off from the transfer belt 64 without providing a new detection means for detecting that the leading edge of the paper P has peeled off from the transfer belt 64.

  In the embodiment described above, the separation claw 70 contacts the transfer belt 64 by energizing the solenoid 71 and is separated from the transfer belt 64 by stopping energization of the solenoid 71. However, the present invention is not limited to this. Alternatively, for example, the separation claw 70 may be brought into contact with or separated from the transfer belt 64 by a motor.

  In the above-described embodiment, the single photoreceptor system and the intermediate transfer system are employed as the printer mechanism 31. However, the present invention is not limited to this, and for example, a direct transfer system that directly transfers from the photoreceptor to the paper P. Or a tandem method including a photoconductor for each color may be employed.

  In the above-described embodiment, the present invention is applied to the color laser printer 10, but the present invention is not limited to this. For example, the present invention is applied to an electronic apparatus having a printing function such as a facsimile machine, a copier, and a multifunction machine. You may apply.

1 is a block diagram showing a schematic configuration of a color laser printer 10. FIG. 1 is a configuration diagram showing a schematic configuration of a color laser printer 10. FIG. FIG. 6 is a configuration diagram showing a schematic configuration of a secondary transfer unit 67. 6 is a flowchart of a print processing routine. 10 is a flowchart of another print processing routine. 10 is a flowchart of another print processing routine.

Explanation of symbols

  10 color laser printer, 20 controller, 21 CPU, 22 ROM, 23 RAM, 24 flash memory, 25 job memory, 26 network board, 27 bus, 30 printer unit, 31 printer mechanism, 32 printer ASIC, 40C, 40M, 40Y, 40K toner cartridge, 51-53 computer, 60 drive roller, 61 developing device, 62 exposure device, 63 photoconductor, 64 transfer belt, 65 paper cassette, 66 transport unit, 67 secondary transfer unit, 68 fixing unit, 69 paper discharge Tray, 70 separation claw, 71 solenoid, 80a first detection sensor, 80b second detection sensor, 81 belt roller, 82 secondary transfer roller.

Claims (13)

An image printing apparatus for printing an image on a print medium,
A toner image forming surface on which a toner image is formed;
Transfer means for transferring the toner image to the print medium by sending out the print medium while pressing the print medium against the toner image forming surface;
A first posture in which the leading end of the print medium fed out while being pressed against the toner image forming surface by the transfer means comes into contact with a position where it can be separated from the toner image forming surface, and a second posture separated from the toner image forming surface. A peeling member capable of taking a posture;
Positioning means for positioning the peeling member in the first posture or the second posture;
An image printing apparatus comprising: The image printing apparatus according to claim 1,
When the print medium is sent out while being pressed against the toner formation surface by the transfer means, the positioning means is controlled so that the peeling member takes the first posture, and the leading edge of the print medium is the toner image formation surface. Control means for performing positioning control to control the positioning means so that the peeling member takes the second posture after peeling from
An image printing apparatus comprising: The image printing apparatus according to claim 2,
Position detecting means for detecting the position of the print medium;
With
The control means, when executing the positioning control, when the print medium is sent out while being pressed against the toner image forming surface by the transfer means, based on the position of the print medium detected by the position detection means. Determining a timing for changing the peeling member from the second posture to the first posture, and controlling the positioning means so that the peeling member takes the first posture at the determined timing;
Image printing device. The image printing apparatus according to claim 2 or 3,
A peeling detection means for detecting whether or not the leading edge of the printing medium has peeled from the toner image forming surface;
With
When the control means performs the positioning control, the peeling member takes the second posture after the peeling detecting means detects that the leading edge of the print medium is peeled from the toner image forming surface. To control the positioning means,
Image printing device. In executing the positioning control, the control means determines whether or not the leading edge of the printing medium has been peeled off from the toner image forming surface based on the time elapsed since the peeling member took the first posture. Determining and controlling the positioning means so that the peeling member takes the second posture after it is determined that the leading edge of the printing medium has peeled from the toner image forming surface;
The image printing apparatus according to claim 2 or 3. The image printing apparatus according to any one of claims 2 to 5,
Input means for inputting image data;
With
The control means determines whether to execute the positioning control based on the image data input to the input means;
Image printing device. The control means grasps a margin amount in a predetermined area on the leading end side of the print medium from the image data, and executes the positioning control when the grasped margin amount is smaller than a predetermined margin amount;
The image printing apparatus according to claim 6. The control means executes the positioning control at the time of marginless printing in which the margin amount is little or substantially zero.
The image printing apparatus according to claim 7. The control means detects the degree of toner adhesion in a predetermined area on the front end side of the print medium from the image data, and executes the positioning control when the detected degree of toner adhesion is greater than a predetermined degree. To
The image printing apparatus according to claim 6. The control means determines whether to execute the positioning control based on a type of the print medium;
The image printing apparatus according to claim 2. The control means executes the positioning control when the print medium is thinner than a predetermined thickness;
The image printing apparatus according to claim 10. An image printing method by computer software for printing an image on a print medium,
A first posture in which a front end of a print medium fed out while being pressed against the toner image forming surface of the toner image forming surface on which the toner image is formed contacts a position where the toner image can be peeled from the toner image forming surface; Using a peeling member capable of taking a second posture separated from the forming surface, and positioning means for positioning the peeling member in the first posture or the second posture,
(A) transferring the toner image to the print medium by sending the print medium while pressing the print medium against the toner image forming surface;
(B) the step of causing the peeling member to take the first posture by the positioning means when the printing medium is sent out while being pressed against the toner image forming surface in the step (a);
(C) after the leading edge of the printing medium is peeled off from the toner image forming surface in the step (b), the step of causing the peeling member to take the second posture by the positioning means;
An image printing method including:   An image printing program for causing one or more computers to execute each step of the image printing method according to claim 12.

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