JP2020139995A - Image forming apparatus - Google Patents

Abstract

To make it possible to correct the rotation speed of a roller so as to prevent the occurrence of expansion and contraction of an image transferred to a medium.SOLUTION: A print motor control unit 164 rotates conveying rollers 116, 117, 118 at a first reference speed that is a rotation speed used for the conveying rollers 116, 117, 118, from a result of detection, with detection sensors 131, 132, of adjacent two positions of a plurality of positions, measures the interval between the positions as a first measured value, rotates the conveying rollers 116, 117, 118 at a second reference speed that is a rotation speed different from the first reference speed, from a result of detection, with the detection sensors 131, 132, of adjacent two positions of the plurality of positions, measures the interval between the positions as a second measured value, and calculates a correction value for correcting the first reference speed such that as a measured value ratio that is the ratio of the difference between the second reference speed and the first reference speed to the difference between the second measured value and the first measured value becomes larger, the correction value becomes larger.SELECTED DRAWING: Figure 4

Description

The present invention relates to an image forming apparatus.

Conventionally, in an image forming apparatus of an intermediate transfer method, transfer is performed after adjusting the transport speed of the medium to the traveling speed of the intermediate transfer belt and aligning the image formed on the intermediate transfer belt with the medium. There is.

Then, in the label paper on the roll in which a plurality of labels are continuously provided on the mount, as disclosed in Patent Document 1, a label position detecting means is provided on the upstream side of the transfer means to detect the label position detecting means. Based on the result, the timing of forming an image on the intermediate transfer belt is controlled.

Japanese Unexamined Patent Publication No. 2017-15921

However, in the conventional technique, although the position of the image and the position of the medium can be matched with high accuracy, the fluctuation of the rotation speed of the roller for transporting the medium and the fluctuation of the transport speed of the medium are not constant. Therefore, there is a problem that the image transferred to the medium is expanded or contracted.

Therefore, one or a plurality of aspects of the present invention make it possible to correct the rotation speed of the rollers so that the image transferred to the medium does not expand or contract.

In the image forming apparatus according to one aspect of the present invention, when the transport roller conveys the medium at a plurality of positions arranged at equal intervals in the transport roller that conveys the medium by rotating. A detection sensor for detecting and a control unit for correcting the rotation speed of the transfer roller according to the detection result of the detection sensor are provided, and the control unit uses the transfer roller in the transfer roller. From the result of rotating at the first reference speed, which is the rotation speed, and detecting two adjacent positions among the plurality of positions by the detection sensor, the interval is measured as the first actual measurement value, and the transport roller is moved. From the result of rotating at a second reference speed, which is a rotation speed different from the first reference speed, and detecting two adjacent positions among the plurality of positions by the detection sensor, the interval is the second measured value. The larger the actual measurement value ratio, which is the ratio of the difference between the second reference speed and the first reference speed, to the difference between the second actual measurement value and the first actual measurement value. It is characterized in that a correction value for correcting the first reference speed is calculated.

According to one or more aspects of the present invention, the rotation speed of the rollers can be corrected so that the image transferred to the medium does not expand or contract.

It is sectional drawing which shows schematic the structure of the image forming apparatus which concerns on Embodiment 1. FIG. (A) to (C) are schematic views of label paper. It is a block diagram which shows schematic structure of the paper feed part. (A) and (B) are block diagrams showing a hardware configuration example of a paper feed control unit. It is a block diagram which shows the structure of the printing part schematicly. (A) and (B) are block diagrams showing a hardware configuration example of a print control unit. It is a flowchart which shows the operation which the print motor control part calculates the correction value for correcting the rotation speed of a transfer roller. It is a schematic diagram which shows the example of the case where the correction value is calculated only by the 1st reference speed. It is the schematic which shows the example in the case of calculating the correction value using the 1st reference speed and the 2nd reference speed. It is a flowchart which shows the operation which starts the speed adjustment of a transfer roller.

Embodiment 1.
FIG. 1 is a cross-sectional view schematically showing the configuration of the image forming apparatus 100 according to the first embodiment.
The image forming apparatus 100 includes a paper feeding unit 101 as a medium supply unit and a printing unit 102 as an image forming unit.
In the image forming apparatus 100, the paper feeding unit 101 supplies the medium, and the printing unit 102 prints (image forming) on the supplied medium.

First, the paper feed unit 101 will be described.
In the present embodiment, the long roll-shaped medium 103 is set in the roll paper holder 104 of the paper feed unit 101. At this time, the medium 103 is pressed against the paper guide 106 by the tension bar 105.

The medium detection sensor 107 detects that the medium 103 is set in the paper feed unit 101.
The paper feeding unit 101 conveys the medium 103 to the printing unit 102 by the rotation of the first conveying roller 108 and the second conveying roller 109.

Further, the paper feeding unit 101 has a cutter 110 for cutting the medium 103, and the cutter input transmission sensor 111 or the cutter input reflection sensor 114 arranged on the upstream side of the cutter 110 identifies the cutting location of the medium 103. To do. The cutter input transmission sensor 111 includes a light emitting unit 112 and a light receiving unit 113.
Further, the cutter output sensor 115 detects the transport state of the medium 103.

Next, the printing unit 102 will be described.
In the printing unit 102, the medium 103 is conveyed by the rotation of the third transfer roller 116, the fourth transfer roller 117, and the fifth transfer roller 118.

The first input sensor 119 detects the state of the medium 103 on the third transfer roller 116, the second input sensor 120 detects the state of the medium 103 on the fourth transfer roller 117, and the third input sensor 121 detects the state of the medium 103. , The state of the medium 103 on the fifth transfer roller 118 is detected.

The image forming execution unit 122 is composed of image drum units 123, 124, 125, 126 of each color such as yellow, magenta, cyan, and black, and first transfers a toner image as a developer image on a transfer belt 127.

The toner image on the transfer belt 127 is conveyed to the position of the secondary transfer roller 129 by the drive of the belt roller 128, and the toner image is secondarily transferred onto the medium 103 conveyed to the position of the secondary transfer roller 129. ..

In the secondary transfer, a high voltage is applied to the secondary transfer backup roller 130 to attach a toner image from the transfer belt 127 to the medium 103.

When the medium 103 is label paper, the input transmission sensor 131 and the input reflection sensor 132 are arranged on the upstream side of the secondary transfer roller 129 in order to secondarily transfer the toner image to a predetermined position, and the medium 103 is a medium. The sensor to be used is selected according to 103.

The medium 103 on which the toner image is formed passes through the fixing portion 133.
When the medium 103 passes between the heat roller 134 inside the fixing portion 133 and the fixing belt 135, the toner image is fixed to the medium 103 by heat and pressure.

The medium 103 on which the toner image is fixed is discharged to the outside of the image forming apparatus 100 by the discharge roller 136.
Further, the discharge sensor 137 detects that the medium 103 has been discharged to the outside of the image forming apparatus 100.

The printing unit 102 has an operation unit 138, and the operation unit 138 includes a display unit for displaying various screen images and an operation panel functioning as an input unit for receiving input of instructions. For example, the operation unit 138 can be configured by a touch panel.

2 (A) to 2 (C) are schematic views of the label paper 180 used as the medium 103.
FIG. 2A is a side view of the label paper 180, FIG. 2B is a front view of the label paper 180 as viewed from the label side, and FIG. 2C is a front view of the label paper 180 as viewed from the mount side. It is a figure.

The label paper 180 is formed by attaching a plurality of labels 182 to a long mount 181 and winding them in a roll shape.
A predetermined gap 183 is provided between the plurality of labels 182.

The mount 181 may have nothing printed on it, or may have a black mark 184, which is a mark for detecting the position, pre-printed on the mount 181.

Here, when the black mark 184 is not provided, for example, as shown in FIG. 2B, the distance between the rear ends of the adjacent labels 182-1 and 182-2 is set. Let l.
When the black mark 184 is provided, as shown in FIG. 2C, the distance between the black marks 184 of the adjacent labels 182-2 and 182-3 is set to l.

In the following description, it is assumed that the black mark 184 is pre-printed on the mount 181. However, the present embodiment is not limited to such an example.

FIG. 3 is a block diagram schematically showing the configuration of the paper feed unit 101.
As described above, the paper feed unit 101 includes the roll paper holder 104, the first transfer roller 108, the second transfer roller 109, the cutter 110, the cutter input transmission sensor 111, the cutter input reflection sensor 114, and the cutter. It includes an output sensor 115.
Further, the paper feed unit 101 includes a paper feed control unit 150, a roll paper motor 153, a paper feed motor 154, and a cutter motor 155.

The paper feed control unit 150 controls the processing in the paper feed unit 101.
The paper feed control unit 150 includes a paper feed motor control unit 151 and a paper feed communication unit 152.
The paper feed motor control unit 151 includes a roll paper motor 153 that drives the roll paper holder 104, a paper feed motor 154 that drives the first transfer roller 108 and the second transfer roller 109, and a cutter motor 155 that drives the cutter 110. To control.
The paper feed communication unit 152 communicates with the printing unit 102.

The paper feed control unit 150 detects whether or not the medium 103 is set based on the detection result of the medium detection sensor 107.
Further, the paper feed control unit 150 monitors the transport state of the medium 103 based on the detection results of the cutter input transmission sensor 111 or the cutter input reflection sensor 114 and the cutter output sensor 115.

As shown in FIG. 4A, the paper feed control unit 150 described above includes a memory 10 and a processor 11 such as a CPU (Central Processing Unit) that executes a program stored in the memory 10. And a microcomputer 1 which is a computer provided with a communication interface (hereinafter referred to as a communication I / F) 12 can be configured. Such a program may be provided through a network, or may be recorded and provided on a recording medium. That is, such a program may be provided as, for example, a program product.

Note that some or all of the processing performed by the paper feed control unit 150 is, for example, a single circuit, a composite circuit, a programmed processor, or parallel programming, as shown in FIG. 4 (B). It can also be executed by a processing circuit 13 such as the processor, ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array).

FIG. 5 is a block diagram schematically showing the configuration of the printing unit 102.
As described above, the printing unit 102 includes the third transfer roller 116, the fourth transfer roller 117, the fifth transfer roller 118, the first input sensor 119, the second input sensor 120, and the third input sensor 121. The image forming execution unit 122, the image drum units 123, 124, 125, 126 of each color, the belt roller 128, the secondary transfer roller 129, the secondary transfer backup roller 130, the input transmission sensor 131, and the input reflection. It includes a sensor 132, a fixing unit 133, a discharge roller 136, a discharge sensor 137, and an operation unit 138.

Further, the printing unit 102 includes a printing control unit 160, a transport motor 170, a discharge motor 171, an ID motor 172, a belt motor 173, a separation motor 174, a high-pressure power supply 175, and a heat roller motor 176. ..

The print control unit 160 includes a connection unit 161, an image formation control unit 162, a storage unit 163, a print motor control unit 164, a high voltage control unit 165, a heater control unit 166, a print communication unit 167, and display control. A unit 168 is provided.

The connection unit 161 communicates with a host device (not shown). For example, the connection unit 161 receives print data from the host device.
The image formation control unit 162 converts the print data received by the connection unit 161 into image data.
The storage unit 163 stores the converted image data.

The print motor control unit 164 includes a transport motor 170 that drives the third transport roller 116, the fourth transport roller 117, and the fifth transport roller 118, a discharge motor 171 that drives the discharge roller 136, and image drum units 123 to 126 of each color. The ID motor 172 that drives the motor, the belt motor 173 that drives the belt roller 128, and the separation motor 174 that separates the secondary transfer roller 129 are controlled.

Here, as will be described later, the print motor control unit 164 of the third transfer roller 116, the fourth transfer roller 117, and the fifth transfer roller 118, depending on the detection result of the input transmission sensor 131 or the input reflection sensor 132. Correct the rotation speed.

Specifically, the printing motor control unit 164 uses the third transfer roller 116, the fourth transfer roller 117, and the fifth transfer roller 118 in the third transfer roller 116, the fourth transfer roller 117, and the fifth transfer roller 118. It was rotated at the first reference speed, which is the rotation speed, and the input transmission sensor 131 or the input reflection sensor 132 detected two adjacent positions among a plurality of positions arranged at equal intervals on the medium 103. From the result, the interval is measured as the first measured value.
Here, the first reference speed is the rotation speed currently used in the third transfer roller 116, the fourth transfer roller 117, and the fifth transfer roller 118, and is the current rotation speed before correction.

Further, the printing motor control unit 164 rotates the third transfer roller 116, the fourth transfer roller 117, and the fifth transfer roller 118 at a second reference speed, which is a rotation speed different from the first reference speed, and inputs the transmission transmission sensor 131. Alternatively, the input reflection sensor 132 measures the interval as the second measured value from the result of detecting two adjacent positions among the plurality of positions.
Here, it is desirable that the second reference speed is a rotation speed faster than the first reference speed.

Then, the print motor control unit 164 increases as the ratio of the measured value, which is the ratio of the difference between the second reference speed and the first reference speed, to the difference between the second measured value and the first measured value, increases. A correction value for correcting the first reference speed, which is the current rotation speed, is calculated.

For example, the print motor control unit 164 sets the correction value as a value obtained by multiplying the ratio of the difference between the first measured value and the theoretical value with respect to the theoretical value which is the theoretical value of the interval by the measured value ratio. Can be done. It is desirable that the theoretical value here is a design value which is the actual length of the interval.
Then, the print motor control unit 164 corrects the first reference speed by multiplying the first reference speed by the calculated correction value.

Hereinafter, the third transfer roller 116, the fourth transfer roller 117, and the fifth transfer roller 118 are also simply referred to as transfer rollers. Here, the third transport roller 116, the fourth transport roller 117, and the fifth transport roller 118 are used as the transport rollers for transporting the medium 103, but the first embodiment is not limited to such an example. For example, the printing unit 102 may be provided with at least one transport roller for transporting the medium 103.

Further, the input transmission sensor 131 and the input reflection sensor 132 are also simply referred to as detection sensors. In the first embodiment, the printing unit 102 uses the input transmission sensor 131 and the input reflection sensor 132 as detection sensors for detecting the position of the medium 103, but the first embodiment is not limited to such an example. .. For example, the printing unit 102 may be provided with at least one detection sensor in order to detect a plurality of positions arranged at equal intervals on the medium 103 when the transfer roller conveys the medium 103.
Further, the print motor control unit 164 is also simply referred to as a control unit.

The high-voltage control unit 165 controls the high-voltage power supply 175 and applies a voltage to the secondary transfer backup roller 130.

Further, the print control unit 160 is in a transport state of the medium 103 based on the detection results of the first input sensor 119, the second input sensor 120, the third input sensor 121, the input transmission sensor 131, the input reflection sensor 132, and the discharge sensor 137. To monitor.

The heater control unit 166 controls the temperature of the heat roller 134 of the fixing unit 133, and the printing motor control unit 164 controls the rotation of the heat roller motor 176. Here, the print motor control unit 164 starts conveying the medium 103 after the heat roller 134 reaches an appropriate temperature.

The print communication unit 167 communicates with the paper feed communication unit 152 of the paper feed unit 101 about the transport status of each of the media 103.
By controlling the operation unit 138, the display control unit 168 displays various information to be notified to the user and accepts input.

As shown in FIG. 6A, the print control unit 160 described above communicates with the memory 20 and a processor 21 such as a CPU that executes a program stored in the memory 20. It can be configured by a microcomputer 2 which is a computer including / F22 and a connection interface (hereinafter, referred to as connection I / F) 23. Such a program may be provided through a network, or may be recorded and provided on a recording medium. That is, such a program may be provided as, for example, a program product.

Note that some or all of the processing performed by the print control unit 160 is, for example, a single circuit, a composite circuit, a programmed processor, or a parallel program as shown in FIG. 6B. It can also be executed by a processing circuit 24 such as a processor, ASIC or FPGA.

FIG. 7 is a flowchart showing an operation in which the print motor control unit 164 calculates a correction value for correcting the rotation speed of the transfer roller.
In the flowchart shown in FIG. 7, for example, the print control unit 160 gives an instruction to start speed adjustment of the third transfer roller 116, the fourth transfer roller 117, and the fifth transfer roller 118 via the operation unit 138. It starts by receiving. In the following description, the third transfer roller 116, the fourth transfer roller 117, and the fifth transfer roller 118 will be described simply as transfer rollers.

First, the print motor control unit 164 acquires the theoretical value l _s , which is the actual interval (design value) of the interval l of the black mark 184 (S10). The theoretical value l _s may be acquired from a host device (not shown) via the connection unit 161 or may receive an input from the user via the operation unit 138. Further, the theoretical value l _s may be stored in advance in the storage unit 163.

Then, the print motor control unit 164, the rotational speed v of the current conveying roller as the first reference speed _{v 1,} to convey the medium 103 into the transport rollers at the first reference speed _{v 1} (S11).
The printing motor control unit 164, the detection result of the input transmission sensor 131 or the input reflection sensor 132, the first measured value l spacing l of the black mark 184 when conveying the medium 103 at the first reference speed _{v 1 1} is acquired (S12).

Then, the print motor control unit 164, the first reference speed _{v 1} in the different second reference speed _{v 2,} to rotate the conveying rollers (S13). Here, the second reference speed v ₂ may be a speed different from the first reference speed v ₁ , but the second reference speed v ₂ is preferably a speed faster than the first reference speed v _1. ..

The printing motor control unit 164, the detection result of the input transmission sensor 131 or the input reflection sensor 132, a second measured value of distance l of the black mark 184 when conveying the medium 103 at the second reference speed _{v 2} l ₂ is acquired (S14).

Then, the print motor control unit 164 uses the following equation (1) using the theoretical value l _s , the first reference speed v ₁ , the second reference speed v ₂ , the first actual measurement value l _1, and the second actual measurement value l _2. ) and the equation (2), calculates the correction value C of the first reference speed _{v 1} is a current rotational speed (S15).
C = {(l _{1 −} l _s ) ÷ l _s } × | t | (1)
t = (v _{1 −} v ₂ ) ÷ (l _{2 −} l ₁ ) (2)

Next, the print motor control unit 164 calculates a new rotation speed v by the following equation (3), and rotates the transport roller at the calculated rotation speed v (S16).
v = v ₁ + (v ₁ x C) (3)

8, without using the second reference speed v _2, is a schematic diagram showing an example of a case of calculating the correction value C of only the first reference speed v _1.
The rotation speed v of the transfer roller when the interval l of the black marks 184 becomes the theoretical value l _s is defined as the rotation speed v _s .

When the interval l of the black marks 184 at the first reference speed v ₁ is the first measured value l ₁ , (l _{1 −} l _s ) ÷ l _s is such that the interval l of the black marks 184 is determined by the transfer speed of the transfer roller. Shows the rate of change.
Therefore, the interval l can be set to the theoretical value l _s by changing the rotation speed v ₁ of the transport roller by this ratio. Therefore, the correction value C is as shown in the following equation (4), and a new rotation speed v can be obtained by the above equation (3).
C = (l _{1 −} l _s ) ÷ l _s (4)

Specifically, when the theoretical value l _s is "100", the first reference velocity v ₁ is "100", and the first measured value l ₁ is "102", the correction value C is the above. According to the formula (4), it becomes "0.02". That is, the interval l is 2% wider than the theoretical value l _s .
Therefore, by 2% faster rotational speed v ₁ by the equation (3), a new rotational speed v is considered to be the rotational speed v _s.

However, depending on the type of the medium 103, the difference in the rotational speeds of the transfer rollers may not always be the difference in the transfer speeds of the medium 103 due to the balance of the holding forces between the transfer rollers and the medium 103. In the above example, it is unclear whether or not the transfer speed of the medium 103 is increased by 2% and the interval l is reduced by 2% by increasing the rotation speed by 2%.

9, as shown in the first embodiment and is a schematic diagram showing an example of a case of calculating the correction value C by using the first reference speed v ₁ and the second reference speed v _2.
According to the above equation (2), the value t is the amount of change in the rotation speed with respect to the amount of change in the interval l.
Therefore, as in the above equation (1), by multiplying the ratio of the amount of change in the interval l by this value t, rotation is performed in order to eliminate the difference between the theoretical value l _s and the first measured value l _1. You can find out how much you have to change the speed.

Specifically, the theoretical value l _s is "100", the first reference speed v ₁ is "100", the first measured value l ₁ is "102", and the second reference speed v 2 is "102". When the second measured value l2 is "101", the correction value C is "0.04" according to the above equations (1) and (2).
Thus, by 4% faster rotational speed v ₁ by the equation (3), a new rotational speed v becomes the rotational speed v _s, so that it is possible to convey the label 182 at intervals of theory l _s become.

As described above, according to the first embodiment, it is possible to eliminate the fluctuation due to the difference between the rotation speed of the transport roller and the transport speed of the medium 103. This makes it possible to prevent the toner image transferred to the medium 103 from expanding and contracting.

Embodiment 2.
In the first embodiment, the image forming apparatus 100 starts the speed adjustment of the transport roller in response to an instruction from the user, but in the second embodiment, the timing of starting the speed adjustment of the transport roller is implemented. An example of changing from the first form is shown.

As shown in FIG. 1, the image forming apparatus 200 according to the second embodiment includes a paper feeding unit 101 as a medium supply unit and a printing unit 202 as an image forming unit.
The paper feeding unit 101 in the second embodiment is the same as the paper feeding unit 101 in the first embodiment.

As shown in FIG. 5, the printing unit 202 in the second embodiment includes a third transfer roller 116, a fourth transfer roller 117, a fifth transfer roller 118, a first input sensor 119, and a second. The input sensor 120, the third input sensor 121, the image forming execution unit 122, the image drum units 123, 124, 125, 126 of each color, the belt roller 128, the secondary transfer roller 129, and the secondary transfer backup roller 130. The input transmission sensor 131, the input reflection sensor 132, the fixing unit 133, the discharge roller 136, the discharge sensor 137, and the operation unit 138 are provided.

Further, the printing unit 202 includes a printing control unit 260, a transport motor 170, a discharge motor 171, an ID motor 172, a belt motor 173, a separation motor 174, a high-pressure power supply 175, and a heat roller motor 176. ..
The printing unit 202 in the second embodiment is configured in the same manner as the printing unit 102 in the first embodiment, except for the print control unit 260.

The print control unit 260 includes a connection unit 161, an image formation control unit 162, a storage unit 163, a print motor control unit 264, a high voltage control unit 165, a heater control unit 166, a print communication unit 167, and display control. A unit 168 is provided.
The print control unit 260 according to the second embodiment is configured in the same manner as the print control unit 160 according to the first embodiment, except for the print motor control unit 264.

The print motor control unit 264 in the second embodiment performs almost the same processing as the print motor control unit 164 in the first embodiment. However, the print motor control unit 164 in the first embodiment has started adjusting the speed of the transfer roller in response to an instruction from the user, but the print motor control unit 264 in the second embodiment has a black mark 184. When the degree of deviation from the theoretical value ls of the measured value l _p of the interval l exceeds a predetermined threshold value, the speed adjustment of the transport roller is started.

Specifically, the print motor control unit 264, to the theoretical value is a theoretical value of the interval of a plurality of positions arranged at equal intervals in the medium 103, it found l _p and the theory is a first measured value When the ratio of the difference from the value exceeds a predetermined threshold value, the first reference speed is corrected.

FIG. 10 is a flowchart showing an operation of starting the speed adjustment of the transfer roller in the second embodiment.
The flowchart shown in FIG. 10 may be performed periodically, or may be performed when the operation unit 138 receives an instruction from the user.
First, the print motor control unit 264 acquires the theoretical value l _s of the interval l of the black mark 184 (S20).

Next, the print motor control unit 264 sets the transfer roller to the current rotation speed v to transfer the medium 103 (S21).
Then, the print motor control unit 264 acquires the actually measured value l _p of the interval l of the black mark 184 when the medium 103 is conveyed at the rotation speed v _p , based on the detection result of the input transmission sensor 131 or the input reflection sensor 132. (S22).

The print motor control unit 264 determines whether or not the following equation (5) is satisfied (S23).
| (L _{s −} l _p ) ÷ l _s × 100 |> Th (5)
Here, Th is a predetermined threshold value.

If the equation (5) is satisfied (Yes in S23), the process proceeds to step S24. In other words, the print motor control unit 264 determines that the speed adjustment is necessary when the equation (5) is satisfied. On the other hand, if the equation (5) is not satisfied (No in S23), the process ends.

In step S24, the print motor control unit 264 adjusts the rotation speed of the transfer roller. Here, the flowchart shown in FIG. 7 is performed. Here, since the theoretical value l _s has already been acquired in step S20 of FIG. 10, it is not necessary to perform step S10 of FIG.
Further, since the actually measured value l _p corresponding to the first actually measured value l ₁ is acquired in step S21 and step S22 of FIG. 10, it is not necessary to perform steps S11 and S12 of FIG.

The print motor control unit 264 may display the speed adjustment execution time on the operation unit 138. Further, the print motor control unit 264 may perform speed adjustment at another timing.

As described above, according to the second embodiment, since the image forming apparatus 200 can determine and execute the time when the speed adjustment is necessary by the apparatus itself, it is always due to the difference between the conveying roller speed and the medium conveying speed. The fluctuation can be eliminated, and the medium 103 can be conveyed by the conveying roller at an ideal speed.
Further, since the speed adjustment time is displayed on the operation unit 138, the user can easily recognize the time when the speed adjustment is required.

As described above, according to the image forming apparatus 100 and 200 according to the first and second embodiments, the image data is stored in order to rotate the transfer roller so as to have the ideal transfer speed of the medium 103 according to the medium 103. Even if the image expansion / contraction adjustment function for correction is not provided, the position of the image can be accurately adjusted and the image expansion / contraction adjustment can be performed.

100, 200 image forming apparatus, 101 paper feed unit, 102, 202 printing unit, 103 medium, 104 roll paper holder, 108 first conveyor roller, 109 second conveyor roller, 110 cutter, 111 cutter input transmission sensor, 114 cutter input Reflection sensor, 115 cutter output sensor, 116 3rd transfer roller, 117 4th transfer roller, 118 5th transfer roller, 119 1st input sensor, 120 2nd input sensor, 121 3rd input sensor, 122 Image formation execution unit, 123, 124, 125, 126 Image Drum Unit, 127 Transfer Belt, 128 Belt Roller, 129 Secondary Transfer Roller, 130 Secondary Transfer Backup Roller, 131 Input Transmission Sensor, 132 Input Reflection Sensor, 133 Fixing Part, 136 Discharge Roller, 137 Ejection sensor, 138 operation unit, 150 paper feed control unit, 151 paper feed motor control unit, 152 paper feed communication unit, 153 roll paper motor, 154 paper feed motor, 155 cutter motor, 160, 260 print control unit, 161 connection unit , 162 Image formation control unit, 163 storage unit, 164,264 print motor control unit, 165 high pressure control unit, 166 heater control unit, 167 print communication unit, 168 display control unit, 170 transfer motor, 171 discharge motor, 172 ID motor , 173 belt motor, 174 separation motor, 175 high pressure power supply, 176 heat roller motor, 180 label paper, 181 mount, 182 label.

Claims (7)

By rotating, the transport roller that transports the medium and
A detection sensor that detects a plurality of positions arranged at equal intervals in the medium when the transfer roller conveys the medium.
A control unit that corrects the rotation speed of the transport roller according to the detection result of the detection sensor is provided.
The control unit
The interval is based on the result of rotating the transfer roller at a first reference speed, which is the rotation speed used by the transfer roller, and detecting two adjacent positions among the plurality of positions by the detection sensor. Is measured as the first measured value,
The distance is determined from the result of rotating the transport roller at a second reference speed, which is a rotation speed different from the first reference speed, and detecting two adjacent positions among the plurality of positions by the detection sensor. Measured as the second measured value,
The first reference speed increases as the ratio of the measured value, which is the ratio of the difference between the second reference speed and the first reference speed, to the difference between the second measured value and the first measured value increases. An image forming apparatus characterized in that a correction value is calculated. The image forming apparatus according to claim 1, wherein the second reference speed is faster than the first reference speed. The control unit sets the correction value as a value obtained by multiplying the ratio of the difference between the first measured value and the theoretical value with respect to the theoretical value which is the theoretical value of the interval by the ratio of the measured value. The image forming apparatus according to claim 1 or 2. When the ratio of the difference between the first measured value and the theoretical value to the theoretical value which is the theoretical value of the interval exceeds a predetermined threshold value, the control unit performs the first reference speed. The image forming apparatus according to claim 1 or 2, wherein the correction is performed. The image forming apparatus according to claim 3 or 4, wherein the theoretical value is a design value which is an actual length of the interval. The image forming apparatus according to any one of claims 1 to 4, wherein the control unit corrects the first reference speed by multiplying the first reference speed by the correction value. The image forming apparatus according to any one of claims 1 to 6, wherein the medium includes a mount and a plurality of labels attached to the mount.

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