JP4790278B2 - Image forming apparatus - Google Patents

Description

The present invention relates to an image forming apparatus.

  Conventionally, an annular belt member that is endlessly moved while being stretched by a plurality of stretch members is used in various fields. For example, in an electrophotographic image forming apparatus, an annular belt member may be used as a latent image carrier such as a photoreceptor or an intermediate transfer member. An electrophotographic image forming apparatus forms an image by the following process. That is, first, a latent image carrier such as a photosensitive member is exposed and scanned to form an electrostatic latent image thereon, and a developer such as a negatively or positively charged toner is attached to the electrostatic latent image to form a toner image. Get. Next, the toner image is directly transferred from the latent image carrier to a recording material such as transfer paper or transferred to the recording material via an intermediate transfer material, and then fixed to the recording material by heating or the like. In such a process, an image forming apparatus using an annular belt member as a latent image carrier or an intermediate transfer member is known.

  In such an image forming apparatus using an annular belt member, there is an image forming start timing and a paper feed timing that are determined based on a detection timing of a reference mark provided at a predetermined position in the circumferential direction of the belt member. For example, Patent Document 1 describes an image forming apparatus that uses a reflective photosensor to detect a reflective reference mark provided at a predetermined position in the circumferential direction of an intermediate transfer belt that is a belt member. In this image forming apparatus, the exposure start timing for the photosensitive member is determined based on the detection timing of the reference mark by the reflective photosensor.

  Also, in an image forming apparatus using an annular belt member, a plurality of marks are provided on the belt member so as to be arranged at a predetermined pitch in the circumferential direction, and the driving speed of the belt member is controlled based on the detection interval of these marks. Are also known (for example, those described in Patent Document 2). In this image forming apparatus, a plurality of marks having light reflectivity are detected by a reflective photosensor, and fluctuations in the running speed of the belt member are detected based on fluctuations in the detection interval. When the speed fluctuates, the driving speed of the belt member is increased or decreased so that the traveling speed matches the target speed. Thereby, the speed fluctuation of the belt member is suppressed.

  In addition, in order to prevent a situation in which the belt is caused to run excessively offset in the width direction on the stretching roller that stretches the belt, the belt is separated from the stretching roller at both ends on the inner peripheral surface of the belt. There are also known ones provided with a stopper guide.

  FIG. 16 shows an example of a conventional belt device. In this belt device, a detent guide 162 is provided at both ends of the inner peripheral surface of the transfer belt 160, and a reference mark 163 is provided on the detent guide 162. In addition, a reflective photosensor 164 that detects the reference mark 163 is provided so as to face the detent guide 162.

Japanese Patent Laid-Open No. 11-15297 JP-A-9-114348

  However, due to the influence of the bias of the belt tension, the assembly accuracy of each stretching roller, etc., the belt 160 is displaced in the belt width direction, and as shown in FIG. In FIG. 16 (b), the right-hand side detent guide in FIG. When such a deviation of the belt 160 occurs, as shown in FIG. 16B, the reflective photosensor 164 does not face the reference mark 163, and the reflective photosensor 164 cannot detect the reference mark 163. If the sensor 164 is unable to detect the reference mark 163, there are problems that it is impossible to determine an appropriate image formation start timing or that a speed variation of the belt member is erroneously detected.

  Therefore, it may be considered to provide a sufficiently long reference mark in the belt width direction. However, the belt becomes larger in the width direction, which increases the size and cost of the device. In addition, if a part of the reference mark enters the area facing the image forming area on the belt outer peripheral surface side, the image formed on the outer peripheral surface of the belt may not be opposed to the area facing the reference mark. In some cases, the image has an abnormal image with a different density. This is because the portion where the reference mark is affixed has higher belt rigidity or higher electrical resistance than the portion where the reference mark is not affixed. As described above, if the rigidity and electric resistance value are different between the portion with and without the reference mark, the transfer nip and the transfer electric field are different between the portion with and without the reference mark. As a result, as described above, the image formed on the outer peripheral surface side of the belt becomes an abnormal image in which the density is different between a position facing the reference mark and a position not facing the reference mark.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a rotational direction position detection mark in the belt width direction even when the belt is displaced and the belt moves in the belt width direction. in without increasing the rotational direction position sensing means to provide the images forming apparatus is Ru can be detected mark detection rotational position.

In order to achieve the above-mentioned object, the invention according to claim 1 is characterized in that an endless belt stretched around a plurality of rollers and at least one of the plurality of rollers are driven to rotationally drive the belt. A belt device comprising: a belt drive device; a rotation direction position detection mark for detecting a position in the belt rotation direction; and a rotation direction position detection means for detecting the rotation direction position detection mark; the toner image forming unit that the belt forms a preparative toner image at a predetermined position of the transfer sheet carrying conveying a plurality placed on the belt surface moving direction, and an image forming unit that forms a multicolor image by superimposing, the An image forming apparatus comprising: a belt drive control device that controls the belt drive device based on a detection result of the rotation direction position detection means of the belt device; and one of the plurality of rollers, Rotation detecting means for detecting the rotational angular velocity or rotational angular displacement of the driven roller that rotates following the endless movement of the belt, and the belt drive control device rotates the roller rotated by the belt drive device at a constant speed. Based on the detection result of the rotation direction position detection means and the detection result of the rotation detection means, belt movement speed fluctuation caused by belt thickness fluctuation is detected, the detected belt movement speed fluctuation, and the belt device Based on the detection result of the rotational direction position detecting means, a target rotation fluctuation for rotating the belt at a constant speed is calculated, and the belt driving device is controlled based on the target rotation fluctuation . A width direction detecting means for detecting movement in the width direction is provided, the rotational position detecting means is configured to be movable in the belt width direction, and the inner peripheral surface end of the belt A detent guide is provided, the belt is rotated a predetermined number of times, and after the detent guide contacts the roller, the direction of movement of the belt is detected by the width direction detection means, and the detection result of the width direction detection means The rotational direction position detecting means is moved based on the rotational direction position detecting means so that the rotational direction position detecting means faces the rotational direction position detecting mark on the belt .
The invention of claim 2 is the image forming apparatus according to claim 1, after moving the rotational position detecting means in the belt width direction based on the movement in the width direction of the belt, the rotational position detecting means It is characterized by fixing.
Further, the invention of claim 3, the image forming apparatus 請 Motomeko 1 or 2,該寄Ri stop guide is provided on one of the belt in the circumferential surface end, the rotational position detection mark, It is provided on the end side having the detent guide.
According to a fourth aspect of the present invention, in the image forming apparatus according to any one of the first to third aspects, the toner has a volume average particle diameter (Dv) and a number average particle diameter (Dv) of 3 to 8 μm. The ratio (Dv / Dn) to Dn) is 1.00 or more and 1.40 or less.
According to a fifth aspect of the present invention, in the image forming apparatus according to any one of the first to fourth aspects, the toner has a shape factor SF-1 of 100 or more and 180 or less and a shape factor SF-2 of 100 or more and 180 or less. It is characterized by being.
According to a sixth aspect of the present invention, in the image forming apparatus according to the first to fifth aspects, the toner includes at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent. It is a toner obtained by crosslinking and / or stretching reaction of a toner material liquid in which the toner is dispersed in an organic solvent in an aqueous medium.
According to a seventh aspect of the present invention, in the image forming apparatus according to any of the first to sixth aspects, the shape of the toner is defined by a major axis r1, a minor axis r2, and a thickness r3 (provided that r1 ≧ r2 ≧ r3), the ratio of the major axis r1 to the minor axis r2 (r2 / r1) is 0.5 or more and 1.0 or less, and the ratio of the thickness r3 to the minor axis r2 (r3 / r2) is 0. 7 or more and 1.0 or less.

  According to the present invention, even if the belt is shifted in the belt width direction due to the influence of the bias of the belt tension or the assembling accuracy of each stretching roller, the rotational direction position detecting means is changed based on the movement in the belt width direction. By moving in the width direction, the rotation direction position detection means can be opposed to the rotation direction position detection mark. As a result, even if the belt is shifted in the belt width direction, the rotation direction position detection means can detect the rotation direction position detection mark, and can appropriately determine an appropriate image formation start timing or change the speed of the belt member. Can be detected well. Further, even if the rotation direction position detection mark is not elongated in the belt width direction, the rotation direction position detection means can detect the rotation direction position detection mark by moving the rotation direction position detection means in the belt width direction. Can do. Therefore, it is possible to suppress the belt from becoming large in the width direction, and it is possible to suppress an increase in size and cost of the apparatus. In addition, since the rotation direction position detection mark does not enter the area facing the image forming area on the belt outer peripheral surface side, it is possible to suppress the occurrence of abnormal images such as different image densities.

Hereinafter, an embodiment in which the present invention is applied to an electrophotographic tandem color laser printer (hereinafter referred to as “laser printer”) as an image forming apparatus will be described.
The tandem type laser printer includes a plurality of photoconductors arranged in parallel, and includes a toner image forming portion that forms each toner image on each photoconductor, and superimposes the color toner images formed on each photoconductor. To obtain a color image. In the tandem type laser printer, there are a method of directly transferring to a transfer sheet (direct transfer method) and a method of final transfer via an intermediate transfer member (intermediate transfer method). The direct transfer method is a method in which an image is directly formed by a toner image forming unit for each color on a transfer sheet conveyed by a transfer conveyance belt. On the other hand, the intermediate transfer method is a method in which an image formed by each color toner image forming unit is once formed on an intermediate transfer belt and then further transferred from the intermediate transfer belt to a transfer sheet.

  Since a tandem type laser printer uses a plurality of photoconductors, toner images of each color can be formed in parallel. Therefore, there is an advantage that the number of output sheets per unit time is larger than that of a so-called revolver type laser printer that repeatedly uses a single photosensitive drum to form each color toner image. On the other hand, since the transfer conveyance belt or the intermediate transfer belt passes through each toner image forming section one after another and obtains a color image, there is a problem that it is difficult to align each color.

  FIG. 1 is a schematic configuration diagram of a laser printer according to the present embodiment. The laser printer according to this embodiment will be described using a direct transfer system. This laser printer transfers four sets of toner image forming portions 1Y, 1M, 1C, and 1K for forming images of each color of yellow (Y), magenta (M), cyan (C), and black (K). They are arranged in order from the upstream side in the moving direction of the paper 100 (the direction in which the belt 60 travels along the arrow A in the figure). Note that the subscripts Y, M, C, and K of the respective symbols indicate members for yellow, magenta, cyan, and black, respectively. Each of the toner image forming units 1Y, 1M, 1C, and 1K includes photosensitive drums 11Y, 11M, 11C, and 11K as image carriers and a developing unit. In addition, the arrangement of the toner image forming units 1Y, 1M, 1C, and 1K is set so that the rotation axes of the photosensitive drums are parallel and arranged at a predetermined pitch in the transfer paper moving direction. .

  In addition to the toner image forming units 1Y, 1M, 1C, and 1K, the laser printer carries the optical writing unit 2, the paper feed cassettes 3, 4, the resist roller pair 5, and the transfer paper 100, and each toner image forming unit. A transfer unit 6 as a belt driving device having a transfer conveyance belt 60 as a transfer conveyance member that conveys the sheet so as to pass through the transfer position, a belt fixing type fixing unit 7, a paper discharge tray 8, and the like. In addition, a manual feed tray MF and a toner replenishing container TC are provided, and a waste toner bottle, a duplex / reversing unit, a power supply unit, and the like (not shown) are also provided in a space S indicated by a two-dot chain line.

  The optical writing unit 2 includes a light source, a polygon mirror, an f-θ lens, a reflection mirror, and the like, and irradiates the surface of each of the photosensitive drums 11Y, 11M, 11C, and 11K while scanning the laser beam based on the image data. .

FIG. 2 is an enlarged view showing a schematic configuration of the transfer unit 6. The transfer conveyance belt 60 used in the transfer unit 6 is a high-resistance endless single-layer belt having a volume resistivity of 10 ⁹ to 10 ¹¹ Ωcm, and the material thereof is PVDF (polyvinylidene fluoride). The transfer / conveying belt 60 is wound around rollers 61 to 68 so as to pass through the transfer positions that contact and face the photosensitive drums 11Y, 11M, 11C, and 11K of the toner image forming units. Among these rollers, the entrance roller 61 on the upstream side in the transfer paper moving direction is disposed on the outer peripheral surface of the transfer conveyance belt 60 so that the electrostatic adsorption roller 80 to which a predetermined voltage is applied from the power source 65a is opposed. . The transfer paper 100 that has passed between the two rollers 61 and 65 is electrostatically attracted onto the transfer conveyance belt 60.

  A roller 63 is a drive roller that frictionally drives the transfer conveyance belt 60, and is connected to a drive source (not shown) and rotates in the direction of the arrow. As a transfer electric field forming means for forming a transfer electric field at each transfer position, transfer bias applying members 67Y, 67M, 67C, and 67K are provided at positions facing the photosensitive drum so as to be in contact with the back surface of the transfer conveyance belt 60. ing. These are bias rollers provided with a sponge or the like on the outer periphery, and a transfer bias is applied to the roller metal from each transfer bias power source 9Y, 9M, 9C, 9K. Due to the action of the applied transfer bias, a transfer charge is applied to the transfer conveyance belt 60, and a transfer electric field having a predetermined strength is formed between the transfer conveyance belt 60 and the surface of the photosensitive drum at each transfer position. In addition, a backup roller 68 is provided to keep the contact between the transfer paper and the photoconductor in the area where the transfer is performed, and to obtain the best transfer nip.

  The transfer bias applying members 67Y, 67M, and 67C and the backup roller 68 disposed in the vicinity thereof are integrally held by the swing bracket 93 so as to be rotatable, and can be rotated around a rotation shaft 94. This rotation is clockwise when the cam 96 fixed to the cam shaft 97 is rotated in the direction of the arrow.

  The entrance roller 61 and the suction roller 80 are integrally supported by the entrance roller bracket 90, and can be rotated clockwise from the state shown in FIG. A hole 95 provided in the swing bracket 93 and a pin 92 fixed to the entrance roller bracket 90 are engaged with each other, and rotate in conjunction with the rotation of the swing bracket 93. By the clockwise rotation of these brackets 90, 93, the bias applying members 67Y, 67M, 67C and the backup roller 68 disposed in the vicinity thereof are separated from the photoreceptors 11Y, 11M, 11C, and the entrance roller 61 and the suction roller 80 also moves downward. It is possible to avoid contact between the photoconductors 11Y, 11M, and 11C and the transfer conveyance belt 60 when forming a black-only image.

  On the other hand, the transfer bias applying member 67K and the backup roller 68 adjacent to the transfer bias applying member 67K are rotatably supported by the outlet bracket 98, and are rotatable about a shaft 99 coaxial with the outlet roller 62. When attaching / detaching the transfer unit 6 to / from the main body, the transfer unit 6K is rotated clockwise by operating a handle (not shown), and the transfer bias applying member 67K and the backup roller 68 adjacent thereto are moved from the black image forming photosensitive member 11K. They are separated.

  A cleaning device 85 composed of a brush roller and a cleaning blade is disposed on the outer peripheral surface of the transfer conveyance belt 60 wound around the driving roller 63. The cleaning device 85 removes foreign matters such as toner adhering to the transfer conveyance belt 60.

  A roller 64 is provided downstream of the driving roller 63 in the traveling direction of the transfer conveyance belt 60 in a direction to push the outer peripheral surface of the transfer conveyance belt, and a winding angle around the drive roller 83 is ensured. A tension roller 65 that applies tension to the belt with a pressing member (spring) 69 is provided in the loop of the transfer conveyance belt 60 further downstream from the roller 64.

  The one-dot chain line in FIG. 1 shown above indicates the conveyance path of the transfer paper 100. The transfer paper 100 fed from the paper feed cassettes 3 and 4 or the manual feed tray MF is transported by transport rollers while being guided by a transport guide (not shown), and is transported to a temporary stop position where the registration roller pair 5 is provided. The transfer paper 100 delivered at a predetermined timing by the registration roller pair 5 is carried on the transfer conveyance belt 60, conveyed toward the toner image forming units 1Y, 1M, 1C, and 1K, and passes through the transfer nips. .

  The toner images developed on the toner drums 11Y, 11M, 11C, and 11K of the toner image forming units 1Y, 1M, 1C, and 1K are superimposed on the transfer paper 100 at the transfer nips, respectively. It is transferred onto the transfer paper 100 under the action of pressure. By this superposition transfer, a full-color toner image is formed on the transfer paper 100. The surfaces of the photosensitive drums 11Y, 11M, 11C, and 11K after the toner image transfer are cleaned by a cleaning device, and are further discharged to prepare for the formation of the next electrostatic latent image.

  On the other hand, the transfer paper 100 on which the full-color toner image is formed is fixed in the first paper discharge direction B or the second in accordance with the rotation posture of the switching guide G after the full-color toner image is fixed by the fixing unit 7. In the paper discharge direction C. When the paper is discharged from the first paper discharge direction B onto the paper discharge tray 8, it is stacked in a so-called face-down state with the image surface down. On the other hand, when the paper is discharged in the second paper discharge direction C, it is conveyed toward another post-processing device (such as a sorter or a binding device) (not shown), or is registered again for double-sided printing via a switchback unit. It is conveyed to the roller pair 5.

  In such a laser printer, it is essential that the transfer conveyance belt 60 moves endlessly while maintaining a constant movement speed. If the transfer belt speed fluctuates during image formation, color misregistration occurs and the image quality of the color image is significantly reduced.

  One of the fluctuations in the speed of the transfer / conveyance belt 60 is caused by the eccentricity of the diameter of the drive roller 63 that regulates the speed of the transfer / conveyance belt 60. In this regard, the eccentricity of the driving roller 63 does not contribute to color misregistration by setting the distances 1Y, 1M, 1C, and 1K between the toner image forming portions to an integral multiple of the circumference of the driving roller of the transfer conveyance belt 60. Can be.

  In order to suppress the speed fluctuation of the transfer belt, as disclosed in Japanese Patent Laid-Open No. 63-81370, a driven roller that contacts the back surface of the transfer belt and rotates at the same speed as the transfer belt is used for speed detection. There is also a method in which the rotation speed of the driven roller is detected by an encoder, and the detected speed is fed back to a servo control circuit so that the drive speed is always equal to a predetermined speed. However, in the method in which the rotation of the driven roller is detected by an encoder and corrected by feedback control, when the thickness of the transfer belt varies, the variation in the thickness of the transfer belt occurs at the location where the rotationally driven drive roller is wound around the transfer belt. As a result, the distance from the center of the driving roller to the belt surface changes, so the belt speed fluctuates. In particular, in the case of an integrally formed seamless belt, a thickness deviation easily occurs around the belt.

  Therefore, in the laser printer of this embodiment, in order to maintain the speed of the transfer / conveyance belt 60 constant, a belt drive control device that corrects a speed variation caused by a change in the thickness of the transfer / conveyance belt is provided.

  FIG. 3 is a block diagram of the belt drive control device. The belt drive control device shown in FIG. 3 includes a motor drive unit 615 and a controller unit 614. The motor driving unit 615 is provided with a known PLL control system 604 including a motor 17, a servo amplifier 603, a loop filter and a charge pump. The servo amplifier 603 has a known current source type configuration that can be configured by detecting the current of the motor 17. The controller unit 614 includes a comparator 605, a target reference signal generation unit 606, a target function calculation unit 607, and a belt cycle variation detection unit 608.

  In addition, a home position mark 613 is provided on the transfer conveyance belt 60, and a belt mark detection sensor 612 for detecting the home position mark 613 is attached to a fixing member in the image forming apparatus. The home position mark 613 is made of a reflective member such as a metal film, and is affixed to an arbitrary position on the belt end or the inner peripheral surface so as not to affect image formation. The home position detection sensor 612 is a reflection type photosensor, and detects the passage of the home position mark 613 and outputs a pulse. The pulse output from the home position detection sensor 612 is sent to the controller unit 614 via the home detection unit 609.

  The rotary encoder provided on the same axis as the driven roller 62 outputs a waveform corresponding to the rotation angle of the driven roller 62. The output waveform is sent to the controller unit 614 via the encoder rotation detection unit 610.

  In this way, the signal sent from the encoder rotation detection unit 610 to the controller unit 614 is sent to the belt cycle fluctuation detection unit 608 or the comparator 605. In the case of a signal detected by a preliminary operation described later, the signal is sent to the belt cycle fluctuation detection unit 608. Further, when the signal is detected for performing feedback control described later, the signal is sent to the comparator 605.

  On the other hand, a signal sent from the home detection unit 609 to the controller unit 614 is sent to the belt cycle variation detection unit 608 or the target function calculation unit 607.

  A signal sent from the encoder rotation detection unit 610 to the belt cycle fluctuation detection unit 608 detects a speed fluctuation caused by a change in the thickness of the belt with reference to a signal from the home detection unit 609, and a target function calculation unit To 607. The output value from the belt period fluctuation detection unit 608 is the amplitude and phase numerical values of the fundamental (first order component) wave and the harmonic component of the speed fluctuation caused by the belt thickness change.

  The target function calculation unit 607 is obtained in advance from the amplitude and phase numerical values of the fundamental and harmonic components of the belt thickness variation obtained by the belt cycle variation detection unit 608, the roller diameter, etc. This is a part for calculating the target rotation fluctuation of the driven roller for making the belt conveyance speed constant by using the stored amplitude correction coefficient η and phase correction value T. By changing the rotational angular velocity of the driven roller in the same manner as the target rotation variation calculated here, the belt conveyance speed can be made constant.

This target rotation fluctuation is set every time image formation is started, the belt is driven, and the home position detection sensor 612 detects the home position mark 613 on the belt. To calculate the target rotation fluctuation, first, when the home position detection sensor 612 detects the home position mark 613 on the belt, the home detection unit 609 starts time measurement. Then, once the home position detection sensor 612 detects the home position mark 613 on the belt, the time measurement is stopped. The time measured by the home detector 609 is sent to the target function calculator 607. In the target function calculation unit 607, an amplitude correction coefficient η is added to the amplitude obtained by the belt cycle fluctuation detection unit 608 with reference to a sine wave having the time measured by the home detection unit 609 as one cycle (in the case of a fundamental wave). Multiplication is performed to determine the amplitude value of the target rotation fluctuation (target function). The target rotation is performed by adding the phase correction value T to the phase obtained by the belt cycle fluctuation detection unit 608 with the Sin wave having the time measured by the home detection unit 609 as one cycle (in the case of a fundamental wave). The phase value of the fluctuation (target function) is determined. Thereby, the target rotation fluctuation (target function) of the fundamental wave is generated. Similarly, in the harmonic component, the amplitude obtained by the belt cycle fluctuation detection unit 608 is multiplied by the amplitude correction coefficient η with reference to sine waves having the time measured by the home detection unit 609 as n cycles, and the belt A phase correction value T is added to the phase obtained by the period variation detector 608 to generate a target rotation variation (target function) of the harmonic component. Then, the target rotation fluctuation (target function) is generated by adding the target function of the fundamental wave and the target function of the harmonic component.
In the above, the target rotation fluctuation (target function) is calculated for each image formation. However, the target rotation fluctuation (target function) is calculated in advance according to the processing capacity and memory capacity of the CPU or DSP in the apparatus. Thus, the numerical values may be stored in a table and read out every image formation.

  The target reference signal generation unit 606 is a part that generates a reference signal for comparison with an encoder output signal fed back by a comparator 605 described later based on the target rotation fluctuation (target function). The reference signal generated by the target reference signal generation unit 606 differs depending on the output signal fed back from the encoder rotation detection unit 610.

  The difference between the target reference signal generated by the target reference signal generation unit 606 and the encoder rotation detection signal fed back is calculated by the comparator 605, and the data is a known value composed of a loop filter and a charge pump of the motor drive unit 615. It is sent to the PLL control system 604. Then, the output is adjusted by PLL control, and the driving torque of the motor is adjusted. Thus, the belt can be conveyed at a desired speed.

  Next, a description will be given of a pre-operation that is performed to detect a speed fluctuation caused by a change in the thickness of the belt and obtain a target rotation fluctuation (target function). FIG. 4 is a flowchart of the preliminary operation. As shown in FIG. 4, first, the motor 17 is driven at a constant speed (S1). Next, it is confirmed whether the motor 17 is rotating at a constant angular velocity (S2). If it is a stepping motor, it is confirmed whether the drive pulse has reached the target frequency. If it is a DC motor, the speed is confirmed from the output of the MR sensor on the motor shaft. In addition to confirming from the rotational speed of the motor 17, the rotational angular speed of the drive roller may be confirmed directly from the rotary encoder. After confirming that the motor is driven at a constant speed (YES in 2), sampling of the belt home position signal and encoder rotation angle information (rotation angle displacement or rotation angular velocity) is started (S3). When sampling is started, it is detected whether the belt has rotated n times (S4). Specifically, it is detected whether the number of detection times of the belt home position mark 613 has been counted a predetermined number of times. When the belt rotates n times (YES in 4), rotation fluctuation data D2 of the driven roller is calculated using the data D1 sampled over the belt n times (S5). Here, the average angular displacement or average angular velocity of the driven roller 14 when the motor 17 is driven at a constant speed is obtained, and the difference between the average data and the sampling data D1 is used as rotational fluctuation data. From the rotation fluctuation data D2, the above-described belt period fluctuation detecting unit 608 calculates the phase based on the amplitude of the speed fluctuation component caused by the change in the belt thickness and the belt home position mark 613 (S6). Similarly, when a high-order component exists, the amplitude and phase of the high-order component are also calculated using quadrature detection (S7).

  A target function is obtained based on the amplitude of the speed fluctuation component resulting from the change in the thickness of the belt and the phase with reference to the belt home position mark 613, which are obtained by the above-described preliminary operation. The speed of the transfer conveyance belt 60 can be made constant by controlling the driving of the motor based on this target function. As described above, since the transfer conveyance belt 60 can be rotated at a constant speed, a good image can be obtained without causing color misregistration or the like on the transfer paper carried on the transfer conveyance belt 60.

  In addition, the transfer conveyance belt 60 of the present embodiment is a roller that is offset in a direction perpendicular to the rotational movement direction (hereinafter referred to as the “width direction”) due to the influence of uneven belt tension, the assembly accuracy of each roller, and the like. A stop guide 620 is provided so as not to fall off. FIG. 5 shows a detent guide 620 of the transfer conveyance belt 60. As shown in FIG. 5, the stopper guide 620 is attached to one end portion of the inner peripheral surface of the transfer conveyance bell 60 by adhesion or pasting with a double-sided tape. The detent guide 620 is made of, for example, a stretchable rubber material such as urethane, and is made of a square band material cut with high accuracy. A guide groove 62a that engages with the detent guide 620 is formed at one end of each roller. Since the side surfaces of the guide grooves of these rollers receive the offset of the offset guide 620, the transfer conveyance belt 60 can be prevented from falling off the rollers. Further, the above-described home position mark 613 is attached to the surface of the detent guide 620 by vapor deposition or the like.

  FIG. 6 is an explanatory view of a main part of a transfer unit (hereinafter referred to as a belt device). As shown in FIG. 6, the home position detection sensor 612 is provided at a position facing the detent guide 620 inside the transfer conveyance belt 60.

  When the belt 60 is assembled to each roller, the detent guide 620 is positioned substantially in the center of the guide groove 62a of the roller, but due to the influence of the bias of the belt tension, the assembly accuracy of the stretching roller, etc. The detent guide 620 moves to one of the side surfaces of the guide groove 62a of the roller. Then, the home position mark 613 adhered to the surface of the stop guide 620 does not face the home position detection sensor 612, and the home position detection sensor 612 may not be able to detect the home position mark 613. For this reason, in this embodiment, the home position detection sensor 612 is moved based on the direction of the belt shift so that the home position detection sensor 612 always faces the home position mark 613. Below, it demonstrates based on each Example.

[Example 1]
Hereinafter, the belt device according to the first embodiment will be described with reference to FIGS. In the belt device according to the first embodiment, a detecting unit that detects a belt shift direction is provided, and the home position detection sensor 612 is moved in the belt shift direction based on the detection result.

  As shown in FIG. 6, a detection mark 630 is attached to one end portion of the outer peripheral surface of the transfer / conveyance belt 60 to detect the movement of the belt in the width direction (shift direction). Further, a belt deviation direction detection sensor 631 for detecting the detection mark 630 is provided.

  As shown in FIG. 7, the detection mark 630 includes a reference line 630a parallel to the belt width direction and a detection line 630b inclined with respect to the belt width direction. The detection line 630b is an inclined line that approaches the reference line 630a as it goes to the back of the apparatus. The reference line 630a and the detection line 630b are made of a highly reflective member such as metal. The belt direction detection sensor 631 is a reflection type photosensor, and detects the passage of the reference line 630a and the detection line 630b and outputs a pulse.

  FIG. 8 is a diagram illustrating the home position detection sensor mounting device 640. As shown in FIG. 8, the home position detection sensor mounting device 640 includes a frame body 643, a slide guide 641, a screw screw 644, and a spring 642. The slide guide 641 penetrates the home position detection sensor 612 and supports the home position detection sensor 612 within the frame body 643. A through hole is provided in the front side surface 643a of the frame body 643, and a screw groove is provided in the inner peripheral surface of the through hole. The screw screw 644 is screwed into the thread groove of the through hole. Further, the tip of the screw screw 644 includes an abutting portion 644 a that abuts against the front side surface 612 a of the home position detection sensor 612. The spring 642 is attached to the device rear side surface 643b of the frame body 643, and biases the home position detection sensor 612 toward the front side of the device. The length in the belt width direction of the frame 643 is set to be the same as the length in the belt width direction of the guide groove 62a of the roller.

  When it is detected by the belt shift detection described later that the transfer conveyance belt 60 is close to the back side of the apparatus, the screw 644 is rotated, and the home position detection sensor 612 is moved against the urging force of the spring 642 so that the frame body 643 is moved. Against the rear side 643b of the apparatus. Accordingly, the home position mark 613 and the home position detection sensor 612 can be opposed to each other even when the belt 60 is located on the back side of the apparatus. On the other hand, when it is detected by the belt deviation detection described later that the transfer / conveying belt 60 is close to the front side of the apparatus, the screw screw 644 is rotated in the reverse direction. Then, the home position detection sensor 612 comes into contact with the front side surface 643a of the frame body 643 by the biasing force of the spring 642. Accordingly, the home position mark 613 and the home position detection sensor 612 can be opposed to each other even when the belt is on the front side of the apparatus. When the home position detection sensor 612 is moved to a position facing the home position mark 613 in this way, the home position detection sensor 612 and the frame body 643 are fixed with screws or the like.

  The screw screw 644 may be rotated manually, or may be automatically performed by attaching a motor to the screw screw 644.

  Next, detection of the belt shift direction will be described. FIG. 9 is a flowchart of detecting the belt deviation direction. As shown in FIG. 9, first, after the transfer / conveying belt 60 is assembled to the rollers, the motor 17 is driven to rotate the transfer / conveying belt 60 a predetermined number of times (S1). As described above, by rotating the transfer conveyance belt 60 a predetermined number of times, the transfer conveyance belt 60 is moved toward one of the belt width directions (the front side of the apparatus or the back side of the apparatus), and the detent guide 620 is a side surface of the roller guide groove. Either one of them. When the belt rotates a predetermined number of times, the belt deviation direction detection sensor 631 is attached to a sensor attachment holder provided at a predetermined location of the printer. This belt deviation direction detection sensor 631 is connected to an external measuring device (not shown). When the belt deviation direction detection sensor 631 is attached, the transfer conveyance belt 60 is rotated by driving the motor 17 at a predetermined angular velocity (S2). Next, it is checked whether or not the belt deviation direction detection sensor 631 detects the reference line 630a (S3). When the belt deviation direction detection sensor 631 detects the reference line 630a (YES in S3), the measuring device starts measuring time (S4). Next, it is checked whether the belt direction detection sensor 631 detects the detection line 630b (S5). When the detection line 630b is detected (YES in S5), the measurement device stops measuring time (S6), and the measurement from the detection of the reference line 630a to the detection line 630b after the belt deviation direction detection sensor 631 detects the reference line 630b. Time t1 is obtained (S7). The memory of the measuring device stores a reference time t2 from when the belt deviation direction detection sensor 631 detects the center of the reference line 630a until the center of the detection line 630b is detected when the motor is driven at a predetermined angular velocity. Has been. Then, the measurement time t1 is compared with the reference time t2 (S8). As a result of the comparison, when the measured time t1 is shorter than the reference time t2 (NO in S8), it is determined that the belt is closer to the back side of the apparatus, and this is displayed on the display unit of the measuring apparatus (S10). . On the other hand, if the measured time t1 is shorter than the reference time t2 as a result of comparison (YES in S8), it is determined that the belt is closer to the front side of the apparatus, and this is displayed on the display unit of the measuring apparatus ( S9).

  Based on the detection result, the operator rotates the screw screw 644 as described above to move the home position mark detection sensor 612 to the front side or the back side of the apparatus, thereby moving the home position mark detection sensor 612 to the frame body 643. Secure to. When the fixing is finished, the belt deviation direction detection sensor 631 is removed from the image forming apparatus.

After the detent guide 620 comes into contact with either one of the side surfaces of the roller guide groove 62a, the belt 60 does not deviate further in the width direction. Therefore, the belt shift detection sensor 631 detects the belt shift direction when the transfer conveyance belt 60 is rotated a predetermined number of times and the shift stop guide 620 is in contact with one of the side surfaces of the roller guide groove 62a. If the home position detection sensor 612 is moved based on the detection result, the home position detection sensor 612 can always be arranged at a position facing the home position mark with only one detection.
Further, after detecting the belt shift direction when the shift stop guide 620 is in contact with either one of the side surfaces of the roller guide groove 62a, the belt shift direction detection sensor 631 is unnecessary. Therefore, the belt shift direction detection sensor 631 detects the belt shift direction when the shift stop guide 620 is in contact with either one of the side surfaces of the roller guide groove 62a, and then the belt shift direction detection sensor 631 is removed. In this case, it is not necessary to provide the belt deviation direction detection sensor 631 for each image forming apparatus, and the cost of the image forming apparatus can be reduced.

  Further, the home position detection sensor 612 is fixed to the frame 643 after the home position mark detection sensor 612 is moved based on the detection result of the belt shift direction. It is possible to suppress the movement to the position of the home position mark 613.

In the above description, the belt shift direction detection sensor 631 connected to the external measuring device is attached when the belt shift is detected, and the belt shift direction detection sensor 631 is removed from the image forming apparatus after the detection is completed. Absent. The configuration may be such that the belt deviation direction detection sensor 631 is connected to a control unit inside the image forming apparatus and attached to the image forming apparatus from the beginning. In this case, the measurement time t1 is obtained by the control unit of the image forming apparatus. Further, the reference time t2 is stored in the storage unit of the image forming apparatus, and the measurement time t1 and t2 are compared by the control unit. The comparison result is displayed on the display unit of the image forming apparatus.
In this way, by including the belt deviation direction detection sensor 631 in the image forming apparatus from the beginning, the belt deviation direction detection sensor 631 connected to the measuring device is prepared to detect the belt deviation, or the belt deviation direction detection is detected. There is no need to attach the sensor 631 inside the image formation. As a result, it is possible to easily detect the direction near the belt.

[Example 2]
Next, the belt device of Example 2 will be described. The belt device according to the second embodiment is configured such that the home position detection sensor 612 moves in conjunction with the movement in the width direction of the belt. Hereinafter, Example 2 is demonstrated based on FIG. 10, FIG.

  FIG. 10 is a diagram illustrating a home position detection sensor mounting device 650 in the belt device according to the second embodiment. As shown in FIG. 10, the home position detection sensor mounting device 650 includes a spring 651, a sliding contact member 652, and a support member 653. The sliding contact member 652 is in sliding contact with the end surface of the transfer conveyance belt 60. One end of the spring 651 is attached to the surface opposite to the surface in contact with the belt end surface of the sliding contact member 652, and the other end is attached to the side wall surface of the image forming apparatus. The spring 651 biases the sliding contact member 652 toward the belt. One end of the support member 653 is attached to the sliding contact member 652. The support member 653 has an arm portion 653a extending parallel to the transfer conveyance belt 60 toward the belt side, and a home position detection sensor 612 is attached to the arm portion 653a so as to face the detent guide 620.

When the belt 60 moves to the right side in the figure due to the influence of the bias of the belt tension or the assembling accuracy of the tension roller, the sliding member 652 is interlocked with the movement of the belt 60 in the width direction by the biasing force of the spring 651. Move to the right in the figure. Then, the support member 653 attached to the sliding contact member 652 also moves to the right side in the drawing. As a result, the home position detection sensor 612 attached to the support member 653 also moves to the right side in the drawing in conjunction with the movement of the belt 60 in the width direction. On the other hand, when the belt 60 moves to the left in the figure, the belt end surface pushes the sliding contact member 652 to the left in the figure, and the home position detection sensor 612 also moves to the left in the figure in conjunction with the movement of the belt 60 in the width direction.
As a result, the home position detection sensor 612 can always face the home position mark 613 adhered to the detent guide surface.

  Moreover, you may comprise the home position detection sensor attachment apparatus 650 as shown in FIG. The home position detection sensor mounting device 660 shown in FIG. 11 includes a first roller member 661 that is in sliding contact with one side surface of the detent guide, and a second roller member 662 that is in sliding contact with the other side surface of the detent guide 620. ing. The detent guide 620 moves between the first roller member 661 and the second roller member 662 so as to be sandwiched between the first roller member 661 and the second roller member 662. A first support member 663 that supports the home position detection sensor 612 extends from the center of the first roller member 661. A second support member 664 that supports the home position detection sensor 612 extends from the center of the second roller member 662. The first support member 663 and the second support member 664 have arm portions 663a and 664a, respectively, and the home position detection sensor 612 is arranged so that the two arm portions 663a and 664a face the detent guide 620. I support it. The home position detection sensor mounting device 660 shown in FIG. 11 is provided with a guide member 665 so that the home position detection sensor 612 does not move in the belt traveling direction. One end of the guide member 665 is attached to the image forming apparatus.

  When the transfer conveyance belt 60 moves to the right side in FIG. 11, the detent guide 620 moves the second roller member 662 to the right side in the figure. As a result, the home position detection sensor 612 connected to the second roller member 662 via the second support member 664 moves to the right in the figure in conjunction with the movement in the width direction of the belt. When the transfer conveyance belt 60 moves to the left side in FIG. 11, the detent guide 620 moves the first roller member 661 to the left side in the figure. As a result, the home position detection sensor 612 connected to the first roller member 661 via the first support member 663 moves to the left in the figure in conjunction with the movement in the width direction of the belt. Thus, also in the home position detection sensor mounting device 660 shown in FIG. 11, the home position detection sensor 612 moves in conjunction with the movement of the belt 60 in the width direction. Thereby, it is possible to always face the home position mark 613 provided on the belt detent guide surface, and the belt home position can be reliably detected.

  In the present embodiment, the home position mark 613 is attached to the surface of the detent guide 620, but the present invention is not limited to this. For example, the home position mark 613 may be provided on the inner side of the detent guide 620, or the home position mark 613 may be provided on the end surface side of the detent guide 620. Further, the home position mark 613 may be provided not only on the belt inner peripheral surface but also on the belt outer peripheral surface.

  Further, the home position mark 613 may be provided on the side opposite to the end surface of the transfer conveyance belt 60 on which the offset guide 620 is provided. However, it is preferable to provide the home position mark 613 on the end face on the side where the detent guide 620 is provided. The end surface on the side where the detent guide 620 is provided is less affected by elongation in the belt width direction of the transfer conveyance belt 60 due to use over time than the end surface on the side where the detent guide 620 is not provided. This is because the detent guide 620 serves as a reinforcing member for the belt 60. Therefore, when the home position mark 613 is provided on the end face on the side where the detent guide 620 is provided, the home position mark 613 does not move due to the extension in the width direction of the belt 60, and the home position mark 613 is stable over time. The position mark 613 can be detected.

  Next, the toner used in this embodiment will be described. The toner used in this embodiment preferably has a volume average particle diameter of 3 to 8 μm in order to reproduce minute dots of 600 dpi or more. Further, the ratio (Dv / Dn) of the volume average particle diameter (Dv) and the number average particle diameter (Dn) of the toner used in the exemplary embodiment is preferably in the range of 1.00 to 1.40. The closer (Dv / Dn) is to 1.00, the sharper the particle size distribution. As described above, when the toner used in the present embodiment is a toner having a small particle size and a narrow particle size distribution, the toner charge amount distribution becomes uniform and a high-quality image with little background fogging can be obtained. . Further, the transfer rate can be increased in the electrostatic transfer system.

  The toner suitably used in the image forming apparatus according to the exemplary embodiment is a toner in which at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent are dispersed in an organic solvent. A toner obtained by crosslinking and / or extending a material solution in an aqueous solvent. Hereinafter, the constituent material and the manufacturing method of the toner will be described.

[polyester]
Polyester can be obtained by a polycondensation reaction between a polyhydric alcohol compound and a polycarboxylic acid compound. Examples of the polyhydric alcohol compound (PO) used here include dihydric alcohol (DIO) and trihydric or higher polyhydric alcohol (TO). DIO can be used alone or mixed with a small amount of TO. Are preferably used. Examples of the dihydric alcohol (DIO) include alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.); alkylene ether glycol (diethylene glycol) , Triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diols (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenols (bisphenol A, bisphenol) F, bisphenol S, etc.); alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adduct of the above alicyclic diol; Alkylene oxide bisphenol (ethylene oxide, propylene oxide, butylene oxide, etc.), etc. adducts. Among them, preferred are alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols, and particularly preferred are alkylene oxide adducts of bisphenols and alkylene glycols having 2 to 12 carbon atoms. It is a combined use. The trihydric or higher polyhydric alcohol (TO) includes 3 to 8 or higher polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); trihydric or higher phenols (Trisphenol PA, phenol novolak, cresol novolak, etc.); and alkylene oxide adducts of the above trivalent or higher polyphenols.

  Examples of the polyvalent carboxylic acid (PC) include a divalent carboxylic acid (DIC) and a trivalent or higher polyvalent carboxylic acid (TC). The DIC can be used alone or mixed with a small amount of TC. It is preferable to use it. Divalent carboxylic acids (DIC) include alkylene dicarboxylic acids (succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acids (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid) And naphthalenedicarboxylic acid). Of these, preferred are alkenylene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms. Examples of the trivalent or higher polyvalent carboxylic acid (TC) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid). In addition, as polyhydric carboxylic acid (PC), you may make it react with polyhydric alcohol (PO) using the above-mentioned acid anhydride or lower alkyl ester (Methyl ester, ethyl ester, isopropyl ester, etc.).

  The ratio of the polyhydric alcohol (PO) and the polycarboxylic acid (PC) is usually 2/1 to 1/1 as an equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. Preferably it is 1.5 / 1-1/1, More preferably, it is 1.3 / 1-1.02 / 1.

  The polycondensation reaction between a polyhydric alcohol (PO) and a polycarboxylic acid (PC) is carried out in the presence of a known esterification catalyst such as tetrabutoxytitanate or dibutyltin oxide, and heated to 150 to 280 ° C. while reducing the pressure as necessary. The produced water is distilled off to obtain a polyester having a hydroxyl group. The hydroxyl value of the polyester is preferably 5 or more, and the acid value of the polyester is usually 1 to 30, preferably 5 to 20. By giving an acid value, it tends to be negatively charged, and furthermore, when fixing to a recording paper, the affinity between the recording paper and the toner is good and the low-temperature fixability is improved. However, when the acid value exceeds 30, there is a tendency to deteriorate with respect to the stability of charging, particularly environmental fluctuation. The weight average molecular weight is 10,000 to 400,000, preferably 20,000 to 200,000. A weight average molecular weight of less than 10,000 is not preferable because offset resistance deteriorates. On the other hand, if it exceeds 400,000, the low-temperature fixability is deteriorated.

  The polyester preferably contains a urea-modified polyester in addition to the unmodified polyester obtained by the polycondensation reaction described above. The urea-modified polyester is obtained by reacting the terminal carboxyl group or hydroxyl group of the polyester obtained by the polycondensation reaction with a polyvalent isocyanate compound (PIC) to obtain a polyester prepolymer (A) having an isocyanate group. It is obtained by cross-linking and / or extending the molecular chain by the reaction of the amine with amines.

  Examples of the polyvalent isocyanate compound (PIC) include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.) ); Aromatic diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanates; Those blocked with caprolactam or the like; and combinations of two or more of these.

  The ratio of the polyvalent isocyanate compound (PIC) is usually 5/1 to 1/1, preferably as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. 4/1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. When [NCO] / [OH] exceeds 5, low-temperature fixability deteriorates. When the molar ratio of [NCO] is less than 1, when a urea-modified polyester is used, the urea content in the ester is lowered and hot offset resistance is deteriorated.

  The content of the polyvalent isocyanate compound (PIC) component in the polyester prepolymer (A) having an isocyanate group is usually 0.5 to 40 wt%, preferably 1 to 30 wt%, more preferably 2 to 20 wt%. . If it is less than 0.5 wt%, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. On the other hand, if it exceeds 40 wt%, the low-temperature fixability deteriorates.

  The number of isocyanate groups contained per molecule in the polyester prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to 2 on average. Five. If it is less than 1 per molecule, the molecular weight of the urea-modified polyester will be low, and the hot offset resistance will deteriorate.

  As amines (B) to be reacted with the polyester prepolymer (A), divalent amine compounds (B1), trivalent or higher polyvalent amine compounds (B2), amino alcohols (B3), amino mercaptans (B4), amino acids (B5), and those obtained by blocking the amino groups of B1 to B5 (B6). Examples of the divalent amine compound (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′-). Dimethyl dicyclohexyl methane, diamine cyclohexane, isophorone diamine, etc.); and aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.) and the like. Examples of the trivalent or higher polyvalent amine compound (B2) include diethylenetriamine and triethylenetetramine. Examples of amino alcohol (B3) include ethanolamine and hydroxyethylaniline. Furthermore, examples of amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan. Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid. Examples of B1 to B5 blocked amino groups (B6) include ketimine compounds and oxazolidine compounds obtained from the amines of B1 to B5 and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). Among these amines (B), preferred are B1 and a mixture of B1 and a small amount of B2.

  The ratio of amines (B) is equivalent to the equivalent ratio [NCO] / [NHx] of isocyanate groups [NCO] in the polyester prepolymer (A) having isocyanate groups and amino groups [NHx] in amines (B). Is usually 1/2 to 2/1, preferably 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2. When [NCO] / [NHx] exceeds 2 or less than 1/2, the molecular weight of the urea-modified polyester becomes low, and the hot offset resistance is deteriorated.

  The urea-modified polyester may contain a urethane bond together with a urea bond. The molar ratio of the urea bond content to the urethane bond content is usually 100/0 to 10/90, preferably 80/20 to 20/80, and more preferably 60/40 to 30/70. When the molar ratio of the urea bond is less than 10%, the hot offset resistance is deteriorated.

  The urea-modified polyester is produced by a one-shot method or the like. Polyhydric alcohol (PO) and polyvalent carboxylic acid (PC) are heated to 150-280 ° C. in the presence of a known esterification catalyst such as tetrabutoxytitanate, dibutyltin oxide, etc., and water generated while reducing the pressure as necessary. Distill off to obtain a polyester having a hydroxyl group. Subsequently, at 40-140 degreeC, this is made to react with polyvalent isocyanate (PIC), and the polyester prepolymer (A) which has an isocyanate group is obtained. Further, this (A) is reacted with amines (B) at 0 to 140 ° C. to obtain a urea-modified polyester.

  When reacting (PIC) and when reacting (A) and (B), a solvent may be used if necessary. Usable solvents include aromatic solvents (toluene, xylene, etc.); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.); esters (ethyl acetate, etc.); amides (dimethylformamide, dimethylacetamide, etc.) and ethers And those inert to isocyanates (PIC), such as tetrahydrofuran (such as tetrahydrofuran).

  In the crosslinking and / or extension reaction between the polyester prepolymer (A) and the amines (B), a reaction terminator may be used as necessary to adjust the molecular weight of the resulting urea-modified polyester. Examples of the reaction terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds).

  The weight average molecular weight of the urea-modified polyester is usually 10,000 or more, preferably 20,000 to 10,000,000, and more preferably 30,000 to 1,000,000. If it is less than 10,000, the hot offset resistance deteriorates. The number average molecular weight of the urea-modified polyester or the like is not particularly limited when the above-mentioned unmodified polyester is used, and may be a number average molecular weight that can be easily obtained to obtain the weight average molecular weight. When the urea-modified polyester is used alone, its number average molecular weight is usually 2000-15000, preferably 2000-10000, more preferably 2000-8000. When it exceeds 20000, the low-temperature fixability and the glossiness when used in a full-color apparatus are deteriorated.

  By using the unmodified polyester and the urea-modified polyester in combination, the low-temperature fixability and the gloss when used in the full-color image forming apparatus 100 are improved. Therefore, it is preferable to use the urea-modified polyester alone. The unmodified polyester may include a polyester modified with a chemical bond other than a urea bond.

  The unmodified polyester and the urea-modified polyester are preferably at least partially compatible with each other in terms of low-temperature fixability and hot offset resistance. Therefore, it is preferable that the unmodified polyester and the urea-modified polyester have a similar composition. The weight ratio of unmodified polyester to urea-modified polyester is usually 20/80 to 95/5, preferably 70/30 to 95/5, more preferably 75/25 to 95/5, and particularly preferably 80 /. 20-93 / 7. When the weight ratio of the urea-modified polyester is less than 5%, the hot offset resistance is deteriorated, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.

  The glass transition point (Tg) of the binder resin containing unmodified polyester and urea-modified polyester is usually 45 to 65 ° C, preferably 45 to 60 ° C. If it is less than 45 ° C., the heat resistance of the toner deteriorates, and if it exceeds 65 ° C., the low-temperature fixability becomes insufficient.

  In addition, since the urea-modified polyester is likely to be present on the surface of the obtained toner base particles, the heat-resistant storage stability tends to be good even when the glass transition point is low as compared with known polyester-based toners.

[Colorant]
As the colorant, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow iron oxide, ocher , Yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Vulcan fast yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Red Dan, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R, Para Red, Phi Sayred, Parachlor Ortonito Aniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine B, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R , Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thio Indigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Pyrazolone Red Polyazo Red, Chrome Vermillion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indanthrene Blue (RS, BC), indigo, ultramarine blue, bitumen, anthraquinone blue, fast violet B, methyl violet lake, cobalt purple, manganese purple, dioxane violet, anthraquinone violet, chrome green, zinc green, chromium oxide, pyridian, emerald green, pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Green Lake, Lid Russian nin green, anthraquinone green, titanium oxide, zinc white, litbon and mixtures thereof can be used. The content of the colorant is usually 1 to 15% by weight, preferably 3 to 10% by weight, based on the toner.

  The colorant can also be used as a master batch combined with a resin. As a binder resin to be kneaded together with the production of the master batch or the master batch, a polymer of styrene such as polystyrene, poly-p-chlorostyrene, polyvinyl toluene or the like, or a copolymer of these and a vinyl compound, Polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, fat Aromatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes and the like can be mentioned, and these can be used alone or in combination.

[Charge control agent]
Known charge control agents can be used, such as nigrosine dyes, triphenylmethane dyes, chromium-containing metal complex dyes, molybdate chelate pigments, rhodamine dyes, alkoxy amines, quaternary ammonium salts (fluorine-modified 4 Secondary ammonium salts or compounds, tungsten simple substances or compounds, fluorine activators, salicylic acid metal salts, and metal salts of salicylic acid derivatives. Specifically, Bontron 03 of a nigrosine dye, Bontron P-51 of a quaternary ammonium salt, Bontron S-34 of a metal-containing azo dye, E-82 of an oxynaphthoic acid metal complex, E-84 of a salicylic acid metal complex , Phenolic condensate E-89 (above, Orient Chemical Industries, Ltd.), quaternary ammonium salt molybdenum complex TP-302, TP-415 (above, Hodogaya Chemical Co., Ltd.), quaternary ammonium salt copy Charge PSY VP2038, copy blue PR of triphenylmethane derivative, copy charge of quaternary ammonium salt NEG VP2036, copy charge NX VP434 (manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit) Manufactured), copper phthalocyanine, perylene, quinacridone, azo series Fee, a sulfonic acid group, a carboxyl group, and polymer compounds having a functional group such as quaternary ammonium salts. Of these, substances that control the negative polarity of the toner are particularly preferably used.

  The amount of charge control agent used is determined by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is not uniquely limited. Preferably, it is used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the charge control agent is reduced, the electrostatic attraction with the developing roller is increased, the developer fluidity is lowered, and the image density is lowered. Invite.

[Release Accelerator]
As the mold release accelerator, a low melting point wax having a melting point of 50 to 120 ° C. works more effectively as a mold release accelerator in the dispersion with the binder resin between the fixing roller and the toner interface. Effective against high temperature offset without applying a release accelerator such as oil to the fixing roller. Examples of such a wax component include the following. Examples of waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax, rice wax, animal waxes such as beeswax and lanolin, mineral waxes such as ozokerite and cercin, and paraffin, microcrystalline, And petroleum waxes such as petrolatum. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax and polyethylene wax, and synthetic waxes such as esters, ketones, and ethers can be used. Furthermore, fatty acid amides such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, chlorinated hydrocarbon, and low molecular weight crystalline polymer resin, poly-n-stearyl methacrylate, poly-n- A crystalline polymer having a long alkyl group in the side chain such as a homopolymer or copolymer of polyacrylate such as lauryl methacrylate (for example, a copolymer of n-stearyl acrylate-ethyl methacrylate, etc.) can also be used. .

  The charge control agent and the mold release accelerator can be melt-kneaded together with the master batch and the binder resin, or, of course, may be added when dissolved and dispersed in the organic solvent.

[External additive]
Inorganic fine particles are preferably used as an external additive for assisting the fluidity, developability and chargeability of the toner particles. The primary particle diameter of the inorganic fine particles is preferably 5 × 10 −3 to 2 μm, and particularly preferably 5 × 10 −3 to 0.5 μm. Moreover, it is preferable that the specific surface area by BET method is 20-500 m <2> / g. The use ratio of the inorganic fine particles is preferably 0.01 to 5 wt% of the toner, and particularly preferably 0.01 to 2.0 wt%.

  Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, quartz sand, clay, mica, wollastonite, diatomaceous earth. Examples include soil, chromium oxide, cerium oxide, bengara, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. Among these, as the fluidity imparting agent, it is preferable to use hydrophobic silica fine particles and hydrophobic titanium oxide fine particles in combination. In particular, when stirring and mixing are performed using particles having an average particle size of 5 × 10-2 μm or less, the electrostatic force and van der Waals force with the toner are remarkably improved. Even when stirring and mixing inside the developing device is performed, a fluidity-imparting agent is not detached from the toner, a good image quality that does not cause fireflies and the like is obtained, and a reduction in residual toner is further achieved. .

  Titanium oxide fine particles are excellent in environmental stability and image density stability, but have a tendency to deteriorate the charge rise characteristics. Therefore, if the amount of titanium oxide fine particles added is larger than the amount of silica fine particles added, this side effect is affected. It can be considered large. However, when the added amount of the hydrophobic silica fine particles and the hydrophobic titanium oxide fine particles is in the range of 0.3 to 1.5 wt%, the charge rising characteristics are not greatly impaired, and the desired charge rising characteristics can be obtained, that is, repeated copying. Stable image quality can be obtained even if

Next, a toner manufacturing method will be described. Here, although a preferable manufacturing method is shown, it is not limited to this.
[Toner Production Method]
(1) A toner material solution is prepared by dispersing a colorant, unmodified polyester, a polyester prepolymer having an isocyanate group, and a release accelerator in an organic solvent. The organic solvent is preferably volatile with a boiling point of less than 100 ° C. from the viewpoint of easy removal after toner base particle formation. Specifically, toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, methyl ethyl ketone, Methyl isobutyl ketone and the like can be used alone or in combination of two or more. In particular, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform, and carbon tetrachloride are preferable. The usage-amount of an organic solvent is 0-300 weight part normally with respect to 100 weight part of polyester prepolymers, Preferably it is 0-100 weight part, More preferably, it is 25-70 weight part.

(2) The toner material liquid is emulsified in an aqueous medium in the presence of a surfactant and resin fine particles. The aqueous medium may be water alone or an organic solvent such as alcohol (methanol, isopropyl alcohol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methyl cellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.). It may be included. The amount of the aqueous medium used relative to 100 parts by weight of the toner material liquid is usually 50 to 2000 parts by weight, preferably 100 to 1000 parts by weight. If the amount is less than 50 parts by weight, the dispersion state of the toner material liquid is poor, and toner particles having a predetermined particle diameter cannot be obtained. If it exceeds 20000 parts by weight, it is not economical. Further, in order to improve the dispersion in the aqueous medium, a dispersant such as a surfactant and resin fine particles is appropriately added. As surfactants, anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters, alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, Quaternary ammonium salt type cationic surfactants such as alkyltrimethylammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts, pyridinium salts, alkylisoquinolinium salts, benzethonium chloride, fatty acid amide derivatives, polyhydric alcohols Nonionic surfactants such as derivatives, for example, amphoteric surfactants such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine And the like. Further, by using a surfactant having a fluoroalkyl group, the effect can be obtained in a very small amount. Preferred anionic surfactants having a fluoroalkyl group include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, 3- [ω-fluoroalkyl (C6-C11 ) Oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [ω-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-C20) carvone Acids and metal salts, perfluoroalkylcarboxylic acids (C7 to C13) and metal salts thereof, perfluoroalkyl (C4 to C12) sulfonic acids and metal salts thereof, perfluorooctanesulfonic acid diethanolamide, N-propyl-N- ( 2-Hydroxyethyl) Perful Olooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. Can be mentioned. Product names include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M Co., Ltd.), Unidyne DS-101. DS-102 (manufactured by Daikin Industries, Ltd.), Megafac F-110, F-120, F-113, F-191, F-812, F-833 (manufactured by Dainippon Ink, Inc.), Xtop EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products), and Fgentent F-100, F150 (manufactured by Neos). Moreover, as the cationic surfactant, aliphatic quaternary ammonium such as aliphatic primary, secondary or secondary amic acid, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt which has a right fluoroalkyl group is used. Salts, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts, trade names include Surflon S-121 (Asahi Glass Co., Ltd.), Florard FC-135 (Sumitomo 3M Co., Ltd.), Unidyne DS-202 (Daikin Industries) Smoke), Megafac F-150, F-824 (Dainippon Ink Co., Ltd.), Xtop EF-132 (Tochem Products), Footage F-300 (Neos), and the like. The resin fine particles are added to stabilize the toner base particles formed in the aqueous medium. For this reason, it is preferable to add so that the coverage existing on the surface of the toner base particles is in the range of 10 to 90%. For example, polymethyl methacrylate fine particles 1 μm and 3 μm, polystyrene fine particles 0.5 μm and 2 μm, poly (styrene-acrylonitrile) fine particles 1 μm, trade names are PB-200H (manufactured by Kao Corporation), SGP (manufactured by Soken Co., Ltd.), Techno Examples include polymer SB (manufactured by Sekisui Chemical Co., Ltd.), SGP-3G (manufactured by Sokensha), and micropearl (manufactured by Sekisui Fine Chemical Co., Ltd.). In addition, inorganic compound dispersants such as tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, and hydroxyapatite can also be used. As a dispersant that can be used in combination with the above-described resin fine particles and inorganic compound dispersant, the dispersed droplets may be stabilized by a polymer protective colloid. For example, acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride and other (meth) acrylic monomers containing hydroxyl groups Bodies such as acrylic acid-β-hydroxyethyl, methacrylic acid-β-hydroxyethyl, acrylic acid-β-hydroxypropyl, methacrylic acid-β-hydroxypropyl, acrylic acid-γ-hydroxypropyl, methacrylic acid-γ-hydroxy Propyl, acrylic acid-3-chloro-2-hydroxypropyl, methacrylic acid-3-chloro-2-hydroxypropyl, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate Luric acid esters, N-methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, or compounds containing vinyl alcohol and a carboxyl group Esters such as vinyl acetate, vinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds, acid chlorides such as acrylic acid chloride, methacrylic acid chloride, vinyl pyridine, vinyl pyrrolidone, vinyl Nitrogen compounds such as imidazole and ethyleneimine, or homopolymers or copolymers such as those having a heterocyclic ring thereof, polyoxyethylene, poly Xoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxy Polyoxyethylenes such as ethylene nonylphenyl ester, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used. The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. Among these, the high-speed shearing method is preferable in order to make the particle size of the dispersion 2 to 20 μm. When a high-speed shearing disperser is used, the rotational speed is not particularly limited, but is usually 1000 to 30000 rpm, preferably 5000 to 20000 rpm. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C.

(3) At the same time as the preparation of the emulsion, the amines (B) are added to cause a reaction with the polyester prepolymer (A) having an isocyanate group. This reaction involves molecular chain crosslinking and / or elongation. The reaction time is selected depending on the reactivity between the isocyanate group structure of the polyester prepolymer (A) and the amines (B), but is usually 10 minutes to 40 hours, preferably 2 to 24 hours. The reaction temperature is generally 0 to 150 ° C, preferably 40 to 98 ° C. Moreover, a well-known catalyst can be used as needed. Specific examples include dibutyltin laurate and dioctyltin laurate.

(4) After completion of the reaction, the organic solvent is removed from the emulsified dispersion (reactant), washed and dried to obtain toner base particles. In order to remove the organic solvent, the temperature of the entire system is gradually raised in a laminar stirring state, and after giving strong stirring in a certain temperature range, the solvent base is removed to produce spindle-shaped toner base particles. . Further, when an acid such as calcium phosphate salt or an alkali-soluble material is used as the dispersion stabilizer, the calcium phosphate salt is dissolved from the toner base particles by a method such as dissolving the calcium phosphate salt with an acid such as hydrochloric acid and washing with water. Remove. It can also be removed by operations such as enzymatic degradation.

(5) A charge control agent is injected into the toner base particles obtained as described above, and then inorganic fine particles such as silica fine particles and titanium oxide fine particles are externally added to obtain a toner. The injection of the charge control agent and the external addition of the inorganic fine particles are performed by a known method using a mixer or the like. Thereby, a toner having a small particle size and a sharp particle size distribution can be easily obtained. Furthermore, by giving strong agitation in the process of removing the organic solvent, the shape between the true spherical shape and the rugby ball shape can be controlled, and the surface morphology is also controlled between the smooth shape and the umeboshi shape. be able to.

As the toner manufactured by the above manufacturing method, it is desirable to use a toner having a shape factor SF-1 in the range of 100 to 180 and a shape factor SF-2 in the range of 100 to 180. The shape factor SF-1 and the shape factor SF-2 are one of the parameters representing the toner shape. The shape factor SF-1 is a value indicating the degree of roundness in a spherical substance such as toner particles. As shown in FIG. 12, the square of the length MXLNG of the maximum diameter portion of an elliptical figure obtained by projecting a spherical substance on a two-dimensional plane is divided by the area AREA, and further multiplied by 100π / 4. . That is, it can be expressed by an expression “SF-1 = ((MXKING) ² / AREA) × (π / 4) × 100”. Note that π is the circumference ratio. A spherical substance having a shape factor SF-1 value of 100 is a true sphere, and the larger the SF-1 value, the more irregular the shape of the spherical substance.

The shape factor SF-2 is a numerical value indicating the degree of unevenness on the surface of the spherical substance. As shown in FIG. 13, it is a value obtained by dividing the square of the perimeter PERI of a figure obtained by projecting a spherical substance on a two-dimensional plane by the area AREA and further multiplying by 100 / 4π. That is, the shape factor SF-2 can be expressed by an expression “SF2 = ((PERI) ² / AREA) × (1 / 4π) × 100”. Note that the spherical material having a shape factor SF-2 of 100 has no irregularities on the surface. As the value of the shape factor SF-2 increases, the irregularities on the surface of the spherical substance become more prominent.

  It has been clarified by the present inventors that the transfer efficiency increases as the toner shape approaches a true sphere (both SF-1 and SF-2 approach 100). This is because the closer to the true sphere, the smaller the contact area between the toner particles and the thing (toner particles, image carrier, etc.) in contact with the toner particles, and the toner fluidity is increased. This is considered to be because the (mirror power) is weakened and is easily affected by the transfer electric field. According to the inventor's research, when the shape factor SF-1 and the shape factor SF-2 exceed 180, the transfer efficiency starts to deteriorate rapidly. If it is 180 or less, a good image without transfer dust can be formed.

  Therefore, in this printer, the user is designated to use toner in the range of 100 to 180 for both the shape factor SF-1 and the shape factor SF-2 by the designation method described later.

  The shape factor SF-1 and the shape factor SF-2 can be obtained as follows. That is, using a FE-SEM (S-800) manufactured by Hitachi, 100 images of toner particles are selected at random, and the images are sequentially taken, and the image information is introduced into an image analyzer (LUSEX 3) manufactured by Nireco. Obtain MXLING, AREA, and PERI. And it calculates as an average value per 100 shape factors obtained by the above-mentioned formula.

  The toner has a substantially spherical shape, and the shape is defined by a major axis length r1, a minor axis length r2, and a thickness r3 (where r1 ≧ r2 ≧ r3), and the ratio between r1 and r2. It is desirable to use those in which (r2 / r1) is in the range of 0.5 to 1.0 and the ratio of r3 to r2 (r3 / r2) is in the range of 0.7 to 1.0.

  14A to 14C are schematic diagrams for explaining the shape of the toner. It is a figure shown typically. In these drawings, the toner described above has a ratio (r2 / r1) of the major axis length r1 to the minor axis length r2 of 0.5 to 1.0. Further, the ratio (r3 / r2) between the thickness r3 and the minor axis length r2 is in the range of 0.7 to 1.0. If the ratio of the major axis length r1 to the minor axis length r2 (r2 / r1) is less than 0.5, the dot reproducibility and transfer efficiency are inferior due to separation from the true spherical shape, and high quality image quality is obtained. It becomes impossible. Further, when the ratio (r3 / r2) of the thickness r3 to the minor axis length r2 is less than 0.7, it becomes close to a flat shape, and a high transfer rate like a spherical toner cannot be obtained. In particular, when the ratio of the thickness to the minor axis length r2 (r3 / r2) is 1.0, a rotating body having the major axis as the rotation axis is obtained, and the fluidity of the toner can be improved. Therefore, in this printer, the user is designated to use the toner having such a configuration by a designation method described later. Note that r1, r2, and r3 can be measured by, for example, the following method. That is, the toner is uniformly dispersed and adhered on a smooth measurement surface, and 100 particles of the toner are magnified 500 times by a color laser microscope “VK-8500” (manufactured by Keyence Corporation). The major axis r1 (μm), the minor axis r2 (μm), and the thickness r3 (μm) of the particles can be measured and obtained from their arithmetic average values.

  A method for designating the user to use a magnetic carrier or toner that satisfies predetermined requirements is as follows. That is, for example, the printer can be shipped with toner satisfying the requirements set in the printer or the developing device. Further, for example, the toner satisfying the requirements may be shipped together with the printer main body and the developing device and shipped. Further, for example, the product number or the product name of the toner satisfying the requirement may be specified in the printer main body, the developing device, and the instruction manuals thereof. Further, for example, the above requirement, product number, product name, etc. may be notified to the user in writing or electronic data.

  In the above embodiment, the present invention is applied to the transfer and conveyance belt of the tandem type image forming apparatus in which a plurality of photosensitive drums 11Y, 11M, 11C, and 11K are arranged on the transfer and conveyance belt 60. The image forming apparatus and the belt apparatus to which the present invention can be applied are not limited to this configuration. Needless to say, the present invention is applicable to an intermediate transfer belt in which an image formed by each color toner image forming unit of a tandem image forming apparatus is formed on a transfer belt and then transferred from the transfer belt to a transfer sheet.

FIG. 15 shows a revolver type image forming apparatus. As shown in FIG. 15, this image forming apparatus is provided with a rotational direction position detection mark 519 for detecting the rotational position of the belt on the inner peripheral surface of the intermediate transfer belt 501 outside the toner image transfer region. . Further, a light detection type position detection sensor 803 for detecting the mark 519 is attached to a support holder (not shown) in a predetermined passing region through which the rotation direction position detection mark 519 passes. When the intermediate transfer belt 501 rotates in the direction of the arrow in the drawing and the position detection mark 519 passes through the detection area of the mark sensor 803, the detection signal of the position detection sensor 803 changes. The revolver-type image forming apparatus includes an alignment control device that controls the rotational position of the intermediate transfer belt 501 to be synchronized with the rotation of the photosensitive drum 100 based on the detection signal of the mark sensor 803.

  The alignment control device performs the following control. When the mark sensor 803 detects the position detection mark 519, a sensor output signal of the mark sensor 803 is input to the control unit of the image forming apparatus via the interface. Based on this output signal, the control unit starts each image formation (first, writing of an electrostatic latent image on the photosensitive drum 100). In this manner, each image formation is started in accordance with the timing at which the position detection sensor 803 detects the detected mark 519, whereby the rotational position of the intermediate transfer belt 501 and the rotational position of the photosensitive drum 100 are synchronized with each other. The transfer position of each color toner image with respect to the intermediate transfer belt 501 is controlled so as not to shift.

Oite the alignment control device of the revolver type image forming apparatus, even close to the intermediate transfer belt 501 occurs, it is possible to position detection sensor 803 detects the detection target mark 519. Accordingly, the timing at which each image formation is started does not deviate, and the transfer position of each color toner image with respect to the intermediate transfer belt 501 does not shift.

  Furthermore, any belt device can be used as long as it is a belt device that rotates and drives an endless belt stretched around a plurality of rollers by at least one of the rollers, and a belt device of an image forming apparatus that has a guide at the end of the belt. Is also applicable. In the above embodiment, the present invention has been described using detection by an optical detection unit. However, the present invention can also be applied to other detection units such as a magnetic detection unit.

(1)
As described above, according to the belt device of the present embodiment, the home position detection sensor as the rotation direction position detection means is moved in the belt width direction based on the movement in the width direction of the belt. As a result, the home position detection sensor is opposed to the home position mark as the rotational position detection mark even if the belt is shifted in the belt width direction due to the influence of the bias of the belt tension or the assembling accuracy of each stretching roller. be able to. As a result, even if the belt moves in the belt width direction, the home position mark can be detected by the home position detection sensor, and an appropriate image formation start timing can be determined well, and belt speed fluctuations can be detected well. Can be.
(2)
Further, according to the belt device of the first embodiment, the width direction detecting means for detecting the movement in the width direction of the belt is provided, and the home position detecting sensor is moved based on the detection result of the width direction detecting means. Specifically, a detection mark comprising a reference line 630a provided on the end face of the belt and parallel to the belt width direction and a detection line 630b inclined with respect to the belt width direction, and a belt for detecting the detection mark The lateral direction detection means is constituted by the shift direction detection sensor. Then, the home position detection sensor is moved based on the detection result of the belt deviation direction detection sensor. Accordingly, the home position detection sensor can be moved based on the movement of the belt in the width direction, and the home position detection sensor can be opposed to the home position mark even if the belt is moved in the belt width direction.
(3)
Further, according to the belt device of the first embodiment, the belt is rotated a predetermined number of times so that the detent guide is brought into contact with the guide groove of the roller, and after the belt stops moving in the width direction, the belt moves in the width direction. Is detected. Thus, the belt moving direction detection sensor only needs to detect the belt moving direction once, and the home position detection sensor only needs to be moved based on the detection result.
(4)
Also, by fixing the home position detection sensor after the home position detection sensor has finished moving, it is possible to prevent the home position detection sensor from moving in the belt width direction for some reason and not facing the home position mark. it can. Therefore, the home position mark can be detected well over time.
(5)
Further, according to the belt device of the second embodiment, the home position detection sensor is configured to move in the width direction of the belt in conjunction with the movement of the belt in the width direction. Thereby, the position of the home position mark detection sensor in the belt width direction can always be the position of the home position mark in the belt width direction. Therefore, the home position mark can be satisfactorily detected by the home position mark detection sensor.
(6)
Further, according to the belt device of the second embodiment, the home position detection sensor includes the sliding contact member that contacts the belt end surface and moves in the belt width direction in conjunction with the movement of the belt end surface in the belt width direction. It is supported by the member. The sliding member moves in conjunction with the movement of the belt end face, so that the home position detection sensor supported by the sliding member can move in the width direction in conjunction with the movement in the width direction of the belt. .
(7)
Further, the first roller member and the second roller as the slidable contact members that move the belt device of the second embodiment in the belt width direction in conjunction with the movement in the belt width direction of the belt guide in contact with the shift guide. The home position detection sensor is supported by the first roller member and the second roller member. When the belt moves in the width direction, the detent guide moves in conjunction with this movement. Then, the first roller member and the second roller member that are in sliding contact with the stopper guide move in conjunction with the stopper guide. When the first roller member and the second roller member move, the home position detection sensor supported by them moves. In this way, the home position detection sensor can be moved in the belt width direction in conjunction with the movement of the detent guide in the belt width direction.
(8)
In addition, according to the belt device of the present embodiment, the belt has the stopper guide at one end portion of the belt, and the home position mark is provided at the end portion where the stopper guide is provided. The detent guide serves as a belt reinforcing member, and the belt end portion side having the detent guide has less influence on the belt in the width direction than the end portion side having no detent guide. For this reason, by providing a home position mark on the belt end side having the detent guide, the belt extends in the width direction due to use over time, etc., so that the detent guide guide prevents the home position mark from facing the home position detection sensor. It can suppress compared with the edge part side which does not have.
(9)
In addition, according to the belt drive control device of the present embodiment, since the belt device having the characteristics (1) to (8) shown above is used, the belt speed fluctuation can be detected well, Good belt drive control can be performed.
(10)
Further, according to the alignment control device of the present embodiment, since the belt device having the features (1) to (8) described above is used, the belt or the transfer paper that is carried and conveyed by the belt is surely obtained. An image can be formed at a predetermined position.
(11)
Further, according to the image forming apparatus of the present embodiment, since the above-described alignment control device (10) is provided, an image is surely placed at a predetermined position of the belt or the transfer paper carried and conveyed by the belt. Can be formed.
(12)
Further, according to the image forming apparatus of the present embodiment, since the belt drive control device (9) described above is provided, a belt speed fluctuation does not occur and a good image can be obtained.
(13)
In addition, according to the image forming apparatus of the present embodiment, it is possible to prevent color misregistration based on belt speed fluctuations and color misregistration based on transfer start timing, and to maintain a color image with a high quality image quality. it can.
(14)
Further, according to the image forming apparatus of the present embodiment, the weight average particle diameter is 3.0 [μm] or more and 8.0 [μm] or less, and the ratio of the weight average particle diameter Dv to the number average particle diameter Dn (Dv / A toner having Dn) of 1.0 or more and 1.40 or less is used. By using a toner having a small particle size and a sharp particle size distribution as described above, an image having excellent sharpness and high definition can be obtained. Further, the toner charge amount distribution is uniform, and a high-quality image with little background stain can be obtained. Furthermore, the transfer rate can be increased in the electrostatic transfer system.
(15)
In this embodiment, toner having a shape factor SF-1 of 100 to 180 and a shape factor SF-2 of 100 to 180 is used. According to experiments, it has been found that when the shape factor SF-1 is 180 or less and the shape factor SF-2 is 180 or less, the transfer efficiency increases as the value approaches 100.
(16)
In the image forming apparatus of this embodiment, a toner material liquid in which a polyester prepolymer having a functional group containing at least a nitrogen atom, a polyester, a colorant, and a release agent is dispersed in an organic solvent is contained in an aqueous solvent. It is produced by cross-linking and / or elongation reaction. Thereby, a toner having a small particle size and a sharp particle size distribution can be easily obtained.
(17)
When the ratio of the major axis to the minor axis (r2 / r1) is less than 0.5, the dot reproducibility and transfer efficiency are inferior because of being away from the true spherical shape, and high-quality image quality cannot be obtained. On the other hand, if the ratio of thickness to minor axis (r3 / r2) is less than 0.7, the shape is close to a flat shape, and a high transfer rate like a spherical toner cannot be obtained. In particular, when the ratio of the thickness to the minor axis (r3 / r2) is 1.0, the rotating body has a major axis as a rotation axis, and the fluidity of the toner can be improved.

1 is a schematic configuration diagram of a laser printer according to an embodiment. FIG. 3 is an enlarged view showing a schematic configuration of a transfer unit. The block diagram of a belt drive control apparatus. The flowchart of prior operation | movement. The schematic block diagram of a stopper guide. Explanatory drawing of the principal part of a transfer unit. The figure which shows a detection mark. 1 is a schematic configuration diagram of a home position detection sensor mounting device according to Embodiment 1. FIG. The flowchart of a belt shift direction detection. The schematic block diagram of the attachment apparatus of the home position detection sensor of Example 2. FIG. The schematic block diagram which shows the other example of the attachment apparatus of the home position detection sensor of Example 2. FIG. Explanatory drawing of shape factor SF-1. Explanatory drawing of shape factor SF-2. FIG. 3 is a diagram schematically illustrating a toner shape. The figure which shows a revolver type image forming apparatus. (A), (b) is a schematic block diagram which shows the conventional transfer belt apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Toner image formation part 2 Optical writing unit 3, 4 Paper feed cassette 5 Registration roller pair 6 Transfer unit 7 Fixing unit 8 Paper discharge tray 11 Photosensitive drum 17 Motor 60 Transfer conveyance belt 80 Electrostatic adsorption roller 609 Home detection part 610 Encoder Rotation detection unit 612 Home position detection sensor 613 Home position mark 614 Controller unit 620 Stop guide 630 Detection mark 631 Belt shift direction detection sensor 640, 650, 660 Home position detection sensor mounting device

Claims (7)

An endless belt stretched around a plurality of rollers, a belt driving device that drives at least one of the plurality of rollers to rotate the belt, and a position for detecting the position in the belt rotation direction a mark detecting rotational position, into position of said the rotational position detection means for detecting a rotational position detecting mark and a belt apparatus provided with a transfer sheet to the belt or the belt is carried and conveyed toner the toner image forming unit that forms an image by a plurality disposed in the belt surface moving direction, and an image forming unit that forms a multicolor image by superimposing, the basis of the detection result of the rotational position detecting means of the belt device In an image forming apparatus comprising a belt drive control device for controlling a belt drive device,
A rotation detecting means that is one of the plurality of rollers, and detects a rotation angular velocity or a rotation angle displacement of a driven roller that rotates following the endless movement of the belt;
The belt drive control device rotates a roller driven to rotate by the belt drive device at a constant speed, and varies the belt thickness based on the detection result of the rotation direction position detection means and the detection result of the rotation detection means. The belt movement speed fluctuation due to the belt is detected, and the target rotation fluctuation for rotating the belt at a constant speed is calculated based on the detected belt movement speed fluctuation and the detection result of the rotational direction position detecting means of the belt device. The belt drive device is controlled based on the target rotation fluctuation,
A width direction detecting means for detecting the movement of the belt in the width direction is provided, the rotational direction position detecting means is configured to be movable in the belt width direction, and a detent guide is provided at an end portion of the inner peripheral surface of the belt,
After the belt is rotated a predetermined number of times and the detent guide comes into contact with the roller, the moving direction of the belt is detected by the width direction detecting means, and the rotational direction position is detected based on the detection result of the width direction detecting means. An image forming apparatus, characterized in that, by moving a detection means, the rotational direction position detection means is opposed to a rotational direction position detection mark on the belt . The image forming apparatus according to claim 1 .
An image forming apparatus, wherein the rotational direction position detecting means is fixed after the rotational direction position detecting means is moved in the belt width direction based on the movement of the belt in the width direction. The image forming apparatus 請 Motomeko 1 or 2,
The image forming apparatus, wherein the detent guide is provided on one of the end portions of the inner peripheral surface of the belt, and the rotational position detection mark is provided on the end portion side having the detent guide. The image forming apparatus according to any one of claims 1 to 3 ,
The toner has a volume average particle diameter of 3 μm or more and 8 μm or less, and a ratio (Dv / Dn) of volume average particle diameter (Dv) to number average particle diameter (Dn) is 1.00 or more and 1.40 or less. An image forming apparatus. The image forming apparatus according to claim 1 ,
The image forming apparatus, wherein the toner has a shape factor SF-1 of 100 or more and 180 or less and a shape factor SF-2 of 100 or more and 180 or less. The image forming apparatus according to any one of claims 1 to 5 ,
In the toner, at least a polyester prepolymer having a functional group containing a nitrogen atom, a polyester, a colorant, and a release agent are dispersed in an organic solvent, and a crosslinking and / or elongation reaction is performed in an aqueous medium. An image forming apparatus, characterized in that the toner is obtained by processing. The image forming apparatus according to claim 1 .
The shape of the toner is defined by a major axis r1, a minor axis r2, and a thickness r3 (where r1 ≧ r2 ≧ r3), and a ratio (r2 / r1) between the major axis r1 and the minor axis r2 is set. An image forming apparatus, wherein the ratio is 0.5 or more and 1.0 or less, and the ratio (r3 / r2) of the thickness r3 to the minor axis r2 is 0.7 or more and 1.0 or less.

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