JP2007232853A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably and effectively control transfer to an intermediate transfer body by a transfer control means, based upon a detection signal of a reference index detecting means when the intermediate transfer body includes a plurality of reference indexes. <P>SOLUTION: The image forming apparatus is characterized in that the intermediate transfer belt is provided with the reference indexes A and B and a transfer control unit controls the time from a time when a reference index detection sensor detects the reference index A or B until a time when the intermediate transfer belt is stopped. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a printer, a copying machine, and a facsimile machine to which an electrophotographic process is applied, and an image forming apparatus that is a multifunction machine having these functions.

Japanese Patent Publication No. 03-066552 Japanese Patent No. 2764929

  In general, an image forming apparatus to which an electrophotographic process is applied includes an image carrier that carries a toner image in which an electrostatic latent image corresponding to image information is formed and the electrostatic latent image is developed with toner, and an image carrier. An intermediate transfer member to which the formed toner image is transferred, a reference indicator is provided on the intermediate transfer member, and a reference indicator detector for detecting the reference indicator of the intermediate transfer member, and a detection signal of the reference indicator detector Are provided with transfer control means for controlling transfer to an intermediate transfer body based on the above.

  Conventionally, in the above image forming apparatus, the transfer control unit controls the transfer to the intermediate transfer body based on the detection signal of the reference index detection unit. However, the intermediate transfer is performed after the reference index detection unit detects the reference index. If the time until the body is stopped is irregular, there is a problem that the transfer control means cannot stably control the transfer to the intermediate transfer body based on the detection signal of the reference index detection means.

  Therefore, as a means for solving the problem that the transfer control means as described above stably controls the transfer to the intermediate transfer body based on the detection signal of the reference index detection means, the following techniques have been conventionally disclosed. .

First, a photosensitive drum, driving means for driving the photosensitive drum, control means for controlling the rotation of the photosensitive drum, and a plurality of surfaces on the surface of the photosensitive drum in synchronization with the rotation of the photosensitive drum. A plurality of clock pulses C indicating that the position of the photosensitive drum passes the predetermined position and a reference pulse S indicating that the reference position on the surface of the photosensitive drum passes the predetermined position are input to the control means. And a reference numerical value Tx representing the number of clock pulses C corresponding to the distance from the position where the reference position on the surface of the photosensitive drum is to be stopped to the predetermined position corresponding to the reference pulse S A first numerical value ty representing the number of clock pulses C that determines the timing at which the control means outputs a rotation stop command of the photosensitive drum to the driving means, and the photosensitive drum In the copier, further comprising a storage unit that stores a second numerical value Δt corresponding to an allowable error range in which an error between the actual stop position of the reference position on the surface of the system and the position to be stopped can be allowed. The number of the clock pulses C input during a period from when the rotation start command of the photosensitive drum is output to the driving means until the reference pulse S is input is counted as the third numerical value Tz. The absolute value | Tδ | of the difference Tδ obtained by subtracting the reference value Tx from the third value Tz is compared with the second value Δt, and the absolute value | Tδ | When the difference is larger than two numerical values Δt, the sum obtained by adding the difference Tδ to the first numerical value ty is stored in the storage means as the first numerical value ty, and the reference pulse S is input after the input. Clock pulse C input The copying machine is characterized in that the power count is counted, the count value is compared with the first numerical value ty, and when both coincide with each other, a rotation stop command for the photosensitive drum is output to the driving means. (See Patent Document 1).
According to this example, for each copy, the microcomputer compares the photosensitive drum stop position at the end of copying with the reference stop position of the photosensitive drum, and generates a photosensitive drum stop timing signal during stop control. Therefore, even if there is a fluctuation in power supply voltage, a change in load, or conversion of parts (such as a motor), the stop position of the photoconductor drum can be kept within a predetermined range.

Second, a reference timing signal generating means for generating a reference timing signal according to the rotational speed of the photosensitive material, a main motor driving means for driving the photosensitive material driving main motor, a counting means for counting the reference timing signal, A stop position calculating means for obtaining a stop position of the light sensitive material based on a counting result of the counting means; In the recording apparatus, the main motor driving means is controlled so as to skip the panel (see Patent Document 2).
According to this example, when the main motor was stopped, the machine clock was monitored until the belt actually stopped, and it was actually stopped by incrementing or decrementing depending on whether it was stopping forward or stopping during reverse rotation. The position can be clarified, and the variation in the stop position can be easily grasped. In addition, the number of machine clocks during movement and the number of machine clocks during reverse rotation are clarified due to the stop inertia of the machine clock number when the actual main motor is stopped. The variation in quantity can be easily grasped, the exact stop position can be set, and the stop position can always be grasped, so that trouble can be easily found and the cause can be easily pursued.

  However, in the above prior art, when the image carrier is provided with one reference index, the transfer control unit can stably control the transfer based on the detection signal of the reference index detection unit. When a plurality of reference indicators are provided on the transfer body, it cannot be effectively solved that the transfer control means stably controls the transfer to the intermediate transfer body based on the detection signal of the reference indicator detection means. There are challenges.

  Therefore, the present invention has been made to solve the above-described problems of the prior art, and an object of the present invention is to provide a reference index in the transfer control means when a plurality of reference indices are provided on the intermediate transfer member. An object of the present invention is to provide an image forming apparatus that can effectively solve the problem of stably controlling the transfer to an intermediate transfer member based on a detection signal of a detection means.

That is, according to the present invention, an image carrier that carries a toner image in which an electrostatic latent image corresponding to image information is formed and the electrostatic latent image is developed with toner, and the toner image formed on the image carrier are transferred. An intermediate transfer body, and a reference index is provided on the intermediate transfer body, and a reference index detection means for detecting the reference index of the intermediate transfer body, and a detection signal from the reference index detection means to the intermediate transfer body In an image forming apparatus including a transfer control unit that controls transfer, the intermediate transfer member is provided with a plurality of reference indexes, and the transfer control unit detects the reference index based on the time between the reference indexes detected by the reference index detection unit. The image forming apparatus is characterized in that the time from when the reference index is detected by the means until the intermediate transfer member is stopped is controlled.
According to this, when a plurality of reference indicators are provided on the intermediate transfer member, it is effective to stably control the transfer to the intermediate transfer member based on the detection signal of the reference indicator detection means by the transfer control means. can do.

  In the present invention, the transfer control means is driven by the transfer speed from the stop of the intermediate transfer body, and the reference index detection means detects the reference index based on the time that the reference index detection means detects the reference index, and then the intermediate transfer body is removed. It is preferable to have a correcting means for correcting the time until stopping, and according to this, it is possible to suppress variations in the stopping position of the intermediate transfer member due to load fluctuations acting on the intermediate transfer member.

  Further, in the present invention, the transfer control means detects the reference index by the reference index detection means based on the time between the reference indices detected by the reference index detection means after accelerating / decelerating from the transfer speed to a different speed, and then performing the intermediate transfer. It is preferable to have a correction means for correcting the time until the body is stopped, and according to this, the intermediate transfer member is stopped by the fluctuation of the load acting on the intermediate transfer member without stopping the intermediate transfer member between the reference indexes. The position variation can be suppressed.

  According to the present invention, when a plurality of reference indexes are provided on the intermediate transfer member, it is effective that the transfer control unit stably controls the transfer to the intermediate transfer member based on the detection signal of the reference index detection unit. An image forming apparatus that can be solved can be provided.

  Embodiments of the present invention will be described below with reference to the drawings.

[First embodiment]
1 to 4 are views showing a first embodiment in an image forming apparatus according to the present invention.

  FIG. 1 is a schematic diagram illustrating an image forming apparatus 10 according to the present embodiment. The image forming apparatus 10 is an image forming apparatus using black (Bk), yellow (Y), magenta (M), and cyan (C) developers (toners). The image forming apparatus 10 is provided with a photosensitive drum 12 that is an image carrier. The photosensitive drum 12 is formed in a cylindrical shape. On the surface of the photosensitive drum 12, an electrostatic latent image for each color in the image information and a toner image in which the electrostatic latent image for each color is developed (visualized) with a corresponding color toner are formed. The photosensitive drum 12 rotates counterclockwise with respect to the front-rear axis. A charger 14 for charging the surface of the photosensitive drum 12 is provided around the photosensitive drum 12. Exposure that forms an electrostatic latent image on the surface of the photosensitive drum 12 charged by the charger 14 at the periphery of the photosensitive drum 12 and downstream of the charger 14 in the rotation direction of the photosensitive drum 12. A device (ROS) 16 is provided. A developing device 18 is provided around the photosensitive drum 12 and downstream of the exposure device 16 in the rotation direction of the photosensitive drum 12. The developing device 18 is formed in a cylindrical shape. The developing device 18 rotates in the clockwise direction with respect to the longitudinal axis. The developing device 18 converts the electrostatic latent image for each color formed on the photosensitive drum 12 with black (Bk), yellow (Y), magenta (M), and cyan (C) toners. It is to be visualized. The developing device 18 includes a black (Bk) developing unit 18a, a yellow (Y) developing unit 18b, a magenta (M) developing unit 18c, and a cyan (C) developing unit 18d. The black (Bk) developing unit 18a, the yellow (Y) developing unit 18b, the magenta (M) developing unit 18c, and the cyan (C) developing unit 18d are substantially equal on the circumference of the developing device 18. Arranged at intervals.

  An intermediate transfer body unit 20 is provided around the photosensitive drum 12 and downstream of the developing device 18 in the rotation direction of the photosensitive drum 12. The intermediate transfer body unit 20 is exposed to a black (Bk) developing unit 18a, a yellow (Y) developing unit 18b, a magenta (M) developing unit 18c, and a cyan (C) developing unit 18d of the developing device 18. A toner image visualized with black (Bk), yellow (Y), magenta (M), and cyan (C) toner images is superimposed on the body drum 12 so that the same position is a reference, and a transfer material Transfer to P. On the intermediate transfer unit 20, a toner image that is brought into contact with the photosensitive drum 12 and visualized with black (Bk), yellow (Y), magenta (M), and cyan (C) toners is displayed. An intermediate transfer belt (intermediate transfer member) 20a that overlaps the same position as a reference is provided. The intermediate transfer belt 20a is pressed against the photosensitive drum 12 by a primary transfer roll (primary transfer means) 20b. The intermediate transfer belt 20a is an endless belt, and is rotationally driven by a drive roll, and a rotation track is formed by a drive roll and a driven roll. The drive roll is rotationally driven by a drive motor (not shown). The intermediate transfer belt 20a rotates in the clockwise direction. On the intermediate transfer unit 20, a toner image visualized with black (Bk), yellow (Y), magenta (M), and cyan (C) toners in contact with the photosensitive drum 12 is displayed. A secondary transfer roll (secondary transfer means) 20c for transferring to the transfer material P is provided. At a predetermined position of the intermediate transfer body unit 20, black (Bk), yellow (Y), magenta (M), and cyan (C) are transferred from the surface of the intermediate transfer belt 20 a by the secondary transfer roll 20 c. After the toner image visualized with toner is transferred to the transfer material P, a cleaning device 20e having a cleaning blade 20d for removing (cleaning) transfer residual toner remaining on the surface of the intermediate transfer belt 20a is disposed. . Further, a reference index detection sensor (reference index detection means) 20f for detecting a reference index provided on the intermediate transfer belt 20a is disposed at a predetermined position of the intermediate transfer body unit 20.

  Black (Bk), yellow (Y), magenta from the surface of the photosensitive drum 12 around the photosensitive drum 12 and downstream of the intermediate transfer unit 20 in the rotation direction of the photosensitive drum 12. A cleaning blade for cleaning the transfer residual toner remaining on the surface of the photosensitive drum 12 after the toner image visualized with the toner of color (M) and cyan (C) is transferred to the intermediate transfer belt 20a. A cleaning device 24 having 24a is arranged.

  A transfer material tray 26 for storing the transfer material P is provided below the image forming apparatus 10. A transfer roll 28 for pressing the transfer material P from above and transporting the transfer material P upward is provided above the transfer material tray 26. Further, a resist roll pair 30 for resisting the transfer material P is provided above the transport roll 28 and below the secondary transfer roll 20c. Above the secondary transfer roll 20c, the intermediate transfer unit 20 overlaps the transfer material P with black (Bk), yellow (Y), magenta (M), and cyan (C) toners. A fixing device 32 for fixing the transferred unfixed toner image on the transfer material P is provided.

  FIG. 2 is a diagram showing reference indices A and B provided on the intermediate transfer belt 20a. The reference indicators A and B are provided at one end of the outer peripheral surface of the intermediate transfer belt 20a so as to be aligned in the rotation direction (sub-scanning direction) of the intermediate transfer belt 20a. For example, when the reference index detection sensor 20f is a reflective photoelectric sensor, the reference indexes A and B are formed of a light reflecting material that reflects light. The reference indexes A and B are formed in a 7 mm × 7 mm square shape, for example. The distances A → B [M] and B → A [M] in the rotational direction of the intermediate transfer belt 20a between the reference indices A and B are A → B [M] −B → A [M] = ΔL [M ] Error has occurred.

  In the image forming apparatus 10 described above, an image is formed on the transfer material P under the control of a transfer control unit (transfer control unit) (not shown) as follows. First, the surface of the photosensitive drum 12 is uniformly charged by the charger 14. Next, an electrostatic latent image corresponding to image information of any one of black color (Bk), yellow color (Y), magenta color (M), and cyan color (C) is formed on the surface of the photosensitive drum 12. Is formed by the exposure device 16. Then, a toner image corresponding to the above color is formed by the developing device 18. Next, a toner image formed on the surface of the photosensitive drum 12 is formed on the surface of the intermediate transfer belt 20a based on a detection signal obtained by detecting the reference index formed on the intermediate transfer belt 20a by the reference index detection sensor 20f. Primary transcription. The above process is carried out for all colors. In the above process, the reference index detected by the reference index detection sensor 20f is the same reference index. Accordingly, the toner image formed on the surface of the photosensitive drum 12 is primarily transferred to the intermediate transfer belt 20a while being superimposed on the same position as a reference. Then, the toner image is secondarily transferred onto the transfer material P by the secondary transfer roll 20c. Next, the unfixed toner image secondarily transferred onto the transfer material P is fixed on the transfer material P by the fixing device 32. Thereafter, the transfer material P is discharged from the fixing device 32.

  FIG. 3 shows black (Bk), yellow (Y), and yellow (Y) on the surface of the intermediate transfer belt 20a based on a detection signal detected by the reference index detection sensor 20f on the reference index formed on the intermediate transfer belt 20a. FIG. 6 is a diagram schematically illustrating a state where toner images of magenta color (M) and cyan color (C) are primarily transferred on the basis of the same position as a reference.

  FIG. 4 is a diagram for explaining a main part of the first embodiment. In the present embodiment, the transfer control unit detects the reference index A or the reference index B with the reference index detection sensor 20f based on the time between the reference indices A and B detected by the reference index detection sensor 20f, and then the intermediate transfer belt. The time until 20a is stopped is controlled. Specifically, in the above routine, the transfer control unit executes the following control. First, when the intermediate transfer belt 20a rotates at a predetermined transfer speed, the transfer control unit detects the reference index A provided on the intermediate transfer belt 20a after the reference index detection sensor 20f detects the intermediate transfer belt 20a. A → B [S], which is the time until the reference index detection sensor 20f detects the reference index B provided on the belt 20a, and the reference index B provided on the intermediate transfer belt 20a. B → A [S], which is the time from when 20f is detected until the reference index detection sensor 20f detects the reference index A provided on the intermediate transfer belt 20a, is measured. The measurement of A → B [S] and B → A [S] is executed during the primary transfer, or is executed by preparing a specific measurement mode. An error of A → B [S] −B → A [S] = ΔT [S] occurs. Accordingly, when the intermediate transfer belt 20a is stopped, the transfer control unit determines whether to stop the intermediate transfer belt 20a based on the reference index A or the reference index B. Next, the transfer control unit calculates a time (IST) from when the above-determined reference index is detected until the intermediate transfer belt 20a is stopped, and after detecting the above-determined reference index, the predetermined time (MST) ) After the lapse of time, the supply of power to the drive motor that rotationally drives the intermediate transfer belt 20a is stopped. The time (IST) until the intermediate transfer belt 20a stops is the inertia of the rotor of the drive motor after the transfer control unit stops supplying power to the drive motor that rotationally drives the intermediate transfer belt 20a. Thus, it becomes longer than the time (MST) until the supply of power to the drive motor that rotationally drives the intermediate transfer belt 20a is stopped. Also, the time (IST) until the intermediate transfer belt 20a is stopped is set at a predetermined transfer speed until the primary transfer start is the fastest and the reference index position where the transfer can be performed stably. It is determined based on the time to stand up.

  As described above, according to the first embodiment, when a plurality of reference indexes are provided on the intermediate transfer belt 20a, the transfer control unit stably transfers the reference index to the intermediate transfer belt 20a based on the detection signal of the reference index detection sensor 20f. Controlling the primary transfer can be effectively solved.

[Second Embodiment]
Next, a second embodiment of the image forming apparatus according to the present invention will be described. In the present embodiment, the same components as those shown in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  FIG. 5 is a diagram for explaining a main part of the second embodiment. In the present embodiment, the transfer control unit detects the reference index A or the reference index B with the reference index detection sensor 20f based on the time between the reference indices A and B detected by the reference index detection sensor 20f, and then the intermediate transfer belt. Further, the transfer control unit is driven by the transfer speed from the stop of the intermediate transfer belt 20a, and the reference index detection sensor 20f detects the reference index A or the reference index B. A correction unit (correction unit) that corrects the time from when the reference index A or the reference index B is detected by the reference index detection sensor 20f to when the intermediate transfer belt 20a is stopped is provided. Specifically, in the above routine, the transfer control unit executes the following control. First, when the intermediate transfer belt 20a rotates at a predetermined transfer speed, the transfer control unit detects the reference index A provided on the intermediate transfer belt 20a after the reference index detection sensor 20f detects the intermediate transfer belt 20a. A → B [S], which is the time until the reference index detection sensor 20f detects the reference index B provided on the belt 20a, and the reference index B provided on the intermediate transfer belt 20a. B → A [S], which is the time from when 20f is detected until the reference index detection sensor 20f detects the reference index A provided on the intermediate transfer belt 20a, is measured. The measurement of A → B [S] and B → A [S] is executed during the primary transfer, or is executed by preparing a specific measurement mode. An error of A → B [S] −B → A [S] = ΔT [S] occurs. Accordingly, when the intermediate transfer belt 20a is stopped, the transfer control unit determines whether to stop the intermediate transfer belt 20a based on the reference index A or the reference index B. Next, the transfer control unit calculates a time (IST) from when the above-determined reference index is detected until the intermediate transfer belt 20a is stopped, and after detecting the above-determined reference index, the predetermined time (MST) ) After the lapse of time, the supply of power to the drive motor that rotationally drives the intermediate transfer belt 20a is stopped. The time (IST) until the intermediate transfer belt 20a stops is the inertia of the rotor of the drive motor after the transfer control unit stops supplying power to the drive motor that rotationally drives the intermediate transfer belt 20a. Thus, it becomes longer than the time (MST) until the supply of power to the drive motor that rotationally drives the intermediate transfer belt 20a is stopped. Also, the time (IST) until the intermediate transfer belt 20a is stopped is set at a predetermined transfer speed until the primary transfer start is the fastest and the reference index position where the transfer can be performed stably. It is determined based on the time to rise (IUT). The IUT varies depending on a change in pressure at which the cleaning blade 20d is in contact with the intermediate transfer belt 20a. That is, IUT (theoretical value) = IUTR (actual value of IUT) ± ΔIUT. Therefore, the correction unit of the transfer control unit first calculates IUTR by measuring IUTR at the start of primary transfer. Next, the correction unit of the transfer control unit feeds back ΔIUT to MST.

  As described above, according to the second embodiment, when a plurality of reference indexes are provided on the intermediate transfer belt 20a, the transfer control unit stably transfers the reference index to the intermediate transfer belt 20a based on the detection signal of the reference index detection sensor 20f. Control of primary transfer can be effectively solved, and variations in the stop position of the intermediate transfer belt 20a due to load fluctuations acting on the intermediate transfer belt 20a can be suppressed.

[Third embodiment]
Next, a third embodiment of the image forming apparatus according to the present invention will be described. In the present embodiment, the same components as those shown in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  FIG. 6 is a diagram for explaining a main part of the third embodiment. In the present embodiment, the transfer control unit detects the reference index A or the reference index B with the reference index detection sensor 20f based on the time between the reference indexes A and B detected by the reference index detection sensor 20f, and then the intermediate transfer belt. The transfer control unit controls the time until stopping 20a, and the transfer control unit decelerates from the transfer speed and uses the reference index detection sensor 20f as a reference based on the time between the reference indices A and B detected by the reference index detection sensor 20f. A correction unit (correction unit) that corrects the time from when the index A or the reference index B is detected until the intermediate transfer belt 20a is stopped is provided. Specifically, in the above routine, the transfer control unit executes the following control. First, when the intermediate transfer belt 20a rotates at a predetermined transfer speed, the transfer control unit detects the reference index A provided on the intermediate transfer belt 20a after the reference index detection sensor 20f detects the intermediate transfer belt 20a. A → B [S], which is the time until the reference index detection sensor 20f detects the reference index B provided on the belt 20a, and the reference index B provided on the intermediate transfer belt 20a. B → A [S], which is the time from when 20f is detected until the reference index detection sensor 20f detects the reference index A provided on the intermediate transfer belt 20a, is measured. The measurement of A → B [S] and B → A [S] is executed during the primary transfer, or is executed by preparing a specific measurement mode. An error of A → B [S] −B → A [S] = ΔT [S] occurs. Accordingly, when the intermediate transfer belt 20a is stopped, the transfer control unit determines whether to stop the intermediate transfer belt 20a based on the reference index A or the reference index B. Next, the transfer control unit calculates a time (IST) from when the above-determined reference index is detected until the intermediate transfer belt 20a is stopped, and after detecting the above-determined reference index, the predetermined time (MST) ) After the lapse of time, the supply of power to the drive motor that rotationally drives the intermediate transfer belt 20a is stopped. The time (IST) until the intermediate transfer belt 20a stops is the inertia of the rotor of the drive motor after the transfer control unit stops supplying power to the drive motor that rotationally drives the intermediate transfer belt 20a. Thus, it becomes longer than the time (MST) until the supply of power to the drive motor that rotationally drives the intermediate transfer belt 20a is stopped. Also, the time (IST) until the intermediate transfer belt 20a is stopped is set at a predetermined transfer speed until the primary transfer start is the fastest and the reference index position where the transfer can be performed stably. It is determined based on the time to stand up. The correction unit of the transfer control unit first decelerates the speed of the drive motor that rotationally drives the intermediate transfer belt 20a during the primary transfer or during a specific measurement mode, and detects it by the reference index detection sensor 20f. The time (DTR) between the reference indices A and B is measured between the reference indices A and B. When the speed of the drive motor that rotationally drives the intermediate transfer belt 20a is decelerated, the cleaning blade 20d uses the intermediate transfer belt 20a for the time (DT) between the reference indices A and B detected by the reference index detection sensor 20f. It fluctuates due to changes in the pressure abutting on the surface. That is, DT (theoretical value) = DTR (actual value of DT) ± ΔDT. Therefore, the correction unit of the transfer control unit then calculates ΔDT. Next, the correction unit of the transfer control unit feeds back ΔDT to MST.

  As described above, according to the third embodiment, when a plurality of reference indexes are provided on the intermediate transfer belt 20a, the transfer control unit stably transfers the reference index to the intermediate transfer belt 20a based on the detection signal of the reference index detection sensor 20f. Control of primary transfer can be effectively solved, and further, the intermediate transfer belt 20a is stopped due to load fluctuations acting on the intermediate transfer belt 20a without stopping the intermediate transfer belt 20a between the reference indices A and B. The position variation can be suppressed.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible within the scope of the summary of this invention.

FIG. 1 is a schematic diagram illustrating an image forming apparatus according to an embodiment. FIG. 2 is a diagram illustrating a reference index provided on the intermediate transfer belt. FIG. 3 shows black (Bk), yellow (Y), and magenta color (Bk) on the surface of the intermediate transfer belt based on the detection signal detected by the reference index detection sensor for the reference index formed on the intermediate transfer belt. FIG. 6 is a diagram schematically illustrating a situation in which toner images of each color of M) and cyan (C) are primarily transferred with being superimposed on the same position as a reference. FIG. 4 is a diagram for explaining a main part of the first embodiment. FIG. 5 is a diagram for explaining a main part of the second embodiment. FIG. 6 is a diagram for explaining a main part of the third embodiment.

Explanation of symbols

  10: Image forming device, 12: Photosensitive drum (image carrier), 20a: Intermediate transfer belt (intermediate transfer member), 20f: Reference index detection sensor (reference index detection means), A, B: Reference index

Claims (3)

An image carrier that carries a toner image in which an electrostatic latent image corresponding to image information is formed and the electrostatic latent image is developed with toner, and an intermediate transfer member on which the toner image formed on the image carrier is transferred In addition, the intermediate transfer body is provided with a reference index, a reference index detection unit that detects the reference index of the intermediate transfer body, and a transfer control that controls transfer to the intermediate transfer body based on a detection signal of the reference index detection unit In an image forming apparatus provided with a means,
The intermediate transfer member is provided with a plurality of reference indexes, and the transfer control unit detects the reference index by the reference index detection unit based on the time between the reference indexes detected by the reference index detection unit, and then stops the intermediate transfer member. An image forming apparatus that controls a time until the image forming operation.   The transfer control unit is driven from the stop of the intermediate transfer member to the transfer speed, and the reference index detection unit detects the reference index based on the time for detecting the reference index until the intermediate transfer member is stopped. The image forming apparatus according to claim 1, further comprising a correcting unit that corrects the time.   The transfer control unit is configured to accelerate and decelerate from the transfer speed to a different speed and detect the reference index with the reference index detection unit based on the time between the reference indexes detected by the reference index detection unit until the intermediate transfer member is stopped. The image forming apparatus according to claim 1, further comprising a correcting unit that corrects the time.

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