JP2020086258A - Image forming device - Google Patents

Abstract

To provide means for suppressing the misalignment of a developer image forming position when a continuous medium meanders.SOLUTION: The present invention comprises: medium conveyance means for conveying a continuous medium using one side in the medium conveyance direction for the continuous medium with a plurality of labels provided thereon as a point of reference; a transfer unit for transferring a developer image formed on an intermediate transfer body to the label of the conveyed continuous medium; detection means for detecting the label of the conveyed continuous medium; a detection means movement control unit for moving the detection means in the medium widthwise direction that is orthogonal to the medium conveyance direction; and an image position correction unit for correcting the position of the developer image formed on the intermediate transfer body on the basis of a label interval in the medium conveyance direction measured by the detection means. The detection means movement control unit moves the detection means to the middle of the continuous medium in the medium widthwise direction, and the image position correction unit corrects the position of the developer image on the basis of the label interval measured by the detection means having been moved to the middle of the continuous medium in the medium widthwise direction.SELECTED DRAWING: Figure 8

Description

The present invention relates to an image forming apparatus that forms an image on label roll paper.

A conventional image forming apparatus conveys a continuous label roll paper having a plurality of labels, and transfers a developer image formed by an image forming unit onto a label to form an image (for example, Patent Document 1). reference).

JP, 2017-15921, A

However, in the related art, the label roll paper as the continuous medium to be conveyed sometimes meanders, and when the label roll paper meanders, the developer image formed on the label shifts from a predetermined position. There is.
An object of the present invention is to solve such a problem, and it is an object of the present invention to suppress the deviation of the formation position of the developer image when the continuous medium meanders.

Therefore, according to the present invention, a medium conveying unit that conveys a continuous medium with a plurality of labels provided on one side in the medium conveying direction as a reference, and an image forming unit that forms a developer image on an intermediate transfer member. A transfer unit for transferring the developer image formed on the intermediate transfer member to the label of the continuous medium conveyed by the medium conveying unit, and the medium conveying unit arranged upstream of the transfer unit in the medium conveying direction. Detecting means for detecting the label of the continuous medium conveyed by, the detecting means movement control section for moving the detecting means in the medium width direction orthogonal to the medium conveying direction, and the label interval in the medium conveying direction measured by the detecting means. And an image position correction unit that corrects the position of the developer image formed on the intermediate transfer member based on the above, and the detection unit movement control unit moves the detection unit to the center of the continuous medium in the medium width direction. Then, the image position correction unit corrects the position of the developer image based on the label interval measured by the detection means moved to the center of the continuous medium in the medium width direction.

The present invention thus configured has an effect that it is possible to suppress the deviation of the formation position of the developer image when the continuous medium meanders.

Schematic side sectional view showing the configuration of the image forming apparatus in the embodiment Schematic side sectional view showing the configuration of the image forming unit in the embodiment Explanatory drawing of the gap type label roll paper in the embodiment Explanatory drawing of the sensor output in an Example Explanatory drawing of label roll paper of black mark type in the example Explanatory drawing of the sensor output in an Example Explanatory drawing of the label pitch detection sensor moving mechanism in an Example Block diagram showing the control configuration of the image forming apparatus in the embodiment Explanatory drawing of movement of label pitch detection sensor in Example Flowchart showing the flow of label pitch detection sensor movement processing in the embodiment Flowchart showing the flow of image forming position correction processing in the embodiment Explanatory drawing of paper detection sensor position in comparative example Model diagram of label pitch measurement in comparative example Explanatory diagram of margin variation in comparative example Explanatory drawing of the inclination of the label tip in the example Model diagram of measurement of label pitch in Example Explanatory diagram of margin variation in the example

Embodiments of an image forming apparatus according to the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic side sectional view showing the structure of an image forming apparatus in the embodiment, and FIG. 2 is a schematic side sectional view showing the structure of an image forming unit in the embodiment.
In FIG. 1, an image forming apparatus 1 forms an image on a label roll paper 70 as a continuous medium, and is, for example, an electrophotographic printer that forms an image by an electrophotographic system. The image forming apparatus 1 may form a monochrome image or a color image, but in the present embodiment, the color image is formed on the label roll paper 70 by the intermediate transfer method. Will be described as a color printer that forms a printer.

The image forming apparatus 1 includes five independent image forming units 20Y, 20M, 20C and 20K corresponding to respective colors of yellow (Y), magenta (M), cyan (C), black (K) and white (W). , 20W.
The image forming units 20Y, 20M, 20C, 20K and 20W as image forming units (image forming means) form a toner image as a developer image on the intermediate transfer belt 12 as an intermediate transfer member. The belts 12 are arranged along the belt 12 sequentially from the upstream side to the downstream side in the rotation direction (conveyance direction) indicated by the arrow A in the figure.

Note that the five image forming units 20Y, 20M, 20C, 20K, and 20W have different toners as a developer to be handled, but the respective configurations are the same, and therefore, in the case of an integrated description, the image forming unit 20 will be described.

As shown in FIG. 2, the image forming unit 20 includes a photoconductor 11 that is a photoconductor drum as an image carrier, a charge roller 21 that is a charging unit that charges the surface of the photoconductor 11, and a charged photoconductor 11. An LED (Light Emitting Diode) head 22 as an exposing means for selectively exposing the surface to write an electrostatic latent image, and a developing means for developing the electrostatic latent image formed on the surface of the photoconductor 11 with toner. The toner is supplied to the surface of the developing roller 23, and the surface of the developing roller 23 and the sponge roller 24 as a supplying unit that rubs the toner between the developing roller 23 and the developing roller 23 to frictionally charge the toner to a negative polarity. A developing blade tail 25 as a regulation means for making the toner a uniform thin layer, a toner tank 26 for supplying the toner to the sponge roller 24, and a cleaning blade 27 for cleaning the toner remaining on the surface of the photoconductor 11. is doing.

The toner tanks 26 store toners of yellow (Y), magenta (M), cyan (C), black (K), and white (W), respectively.

The intermediate transfer belt 12 is an endless belt stretched around the belt driving roller 13, the idle roller 14, the secondary transfer backup roller 16 b, the assist roller 17, and the tension roller 18.
The intermediate transfer belt 12 rotates in a rotation direction indicated by an arrow A in the drawing by rotation of a belt driving roller 13 driven by a driving source such as a motor.

Further, primary transfer rollers 15Y, 15M, 15C, 15K and 15W are arranged at positions facing the photoconductors 11 of the image forming units 20Y, 20M, 20C, 20K and 20W with the intermediate transfer belt 12 interposed therebetween. Has been done.
The primary transfer rollers 15Y, 15M, 15C, 15K, and 15W are pressed against the photoconductors 11 of the image forming units 20Y, 20M, 20C, 20K, and 20W by biasing means such as springs to perform the primary transfer. A primary transfer nip portion is formed as a portion.

At the primary transfer nip portion, the primary transfer of the toner image formed on the photoconductor 11 of each of the image forming units 20Y, 20M, 20C, 20K, and 20W onto the intermediate transfer belt 12 is performed. The intermediate transfer belt 12 on which the toner image is primarily transferred carries the toner image transferred on the surface and is conveyed to the secondary transfer nip portion 16 formed by the secondary transfer roller 16a and the secondary transfer backup roller 16b. To be done.

The label roll paper 70 is a roll-shaped continuous medium that is preliminarily wound around the core, and is supported by the holder 30 so as to be rotatable around the core. The user attaches the label roll paper 70 to the holder 30 in a state where the side end portion of the label roll paper 70 is pushed in until it comes into close contact with the position reference side surface.
The label roll paper 70 is provided with a plurality of labels in the medium transport direction, and a toner image is formed on each label.

When the label roll paper 70 is passed under the tension bar 31 and the leading end is inserted into the medium insertion opening of the image forming apparatus 1, the paper sensor 41 detects the presence of paper, and the feed roller motor is driven to feed the label roll paper 70. When 32 is rotated, it is transported in the medium transport direction indicated by arrow B in the figure.
The label roll paper 70 conveyed along with the rotation of the feeding roller 32 is pulled out from the roll state, and tension is applied by the rotation of the tension bar 31 and the holder 30 having a certain torque in the paper rewinding direction. While being conveyed, it is conveyed into the image forming apparatus 1.

A cut position detection, which includes a reflective sensor 42a as a light reflective sensor, a transmissive sensor light receiving portion 42b and a transmissive sensor light emitting portion 42c as light transmissive sensors, is provided downstream of the feeding roller 32 in the medium transport direction. A sensor 42 is provided.
Based on the detection result of the cut position detection sensor 42, the cutter unit 33 as a cutting unit cuts the label roll paper 70 at a specified position or a label gap position (between labels) after a specified number of labels.

The label roll paper 70 is transported downstream by the plurality of transport rollers 34 (34a, 34b, 34c, 34d) in the medium transport direction, and the secondary transfer formed by the secondary transfer roller 16a and the secondary transfer backup roller 16b. The toner image is nipped by the nip portion 16, that is, the secondary transfer nip portion 16 that secondarily transfers the toner image onto the label roll paper 70.

The transport roller 34 (34a, 34b, 34c, 34d) as a medium transport unit transports the label roll paper 70 in a state in which the side end portion of the holder 30 is pushed in until it comes into close contact with the position reference side surface. That is, the transport rollers 34 (34a, 34b, 34c, 34d) transport the label roll paper 70 in the medium transport direction indicated by the arrow B in the figure with reference to one side in the medium transport direction.

The secondary transfer nip portion 16 serving as a transfer portion (secondary transfer portion) is provided on the label roll paper 70 in which the toner image formed on the intermediate transfer belt 12 is transported by the transport rollers 34 (34a, 34b, 34c, 34d). Transfer to label.
When performing printing to form a toner image on the label roll paper 70, the labels (labels 71 shown in FIGS. 4 and 5) arranged on the label roll paper 70 and the toner image on the intermediate transfer belt 12 are separated. The toner images on the intermediate transfer belt 12 are secondarily transferred to the correctly positioned label by matching the timing of reaching the next transfer nip portion 16.

The timing at which the label of the label roll paper 70 reaches the secondary transfer nip portion 16 is detected by the label pitch detection sensor 43 arranged upstream of the secondary transfer nip portion 16 in the medium transport direction.
The label pitch detection sensor 43 as a detection unit is composed of a reflective sensor 43a, a transmissive sensor light receiving portion 43b and a transmissive sensor light emitting portion 43c, like the cut position detection sensor 42. Further, the label pitch detection sensor 43 is configured to be movable in the width direction of the label roll paper 70 orthogonal to the medium transport direction.

The label pitch detection sensor 43 is a detection unit that detects the leading end of the label of the label roll paper 70 in the medium conveyance direction and measures the interval between adjacent labels (hereinafter referred to as “label pitch”).
When the label pitch detection sensor 43 detects the leading end of the label on the label roll paper 70, the label roll paper 70 is conveyed by the transport rollers 34a, 34b, 34c, and 34d at the arrival timing of the toner image on the intermediate transfer belt 12. The toner image is transferred to the label by finely adjusting the conveying speed.

Since the toner images on the intermediate transfer belt 12 are continuously transferred to the second and subsequent labels, the transport speed of the label roll paper 70 is constant and the transport speed of the label roll paper 70 is constant. From this timing, the label pitch measurement and the feedback control based on the measurement result are started.
In the image forming apparatus 1 according to the present exemplary embodiment, the distance between the label pitch detection sensor 43 and the secondary transfer nip portion 16 is the position where the toner image is formed in the image forming unit 20 (in the rotation direction of the intermediate transfer belt 12). The distance is shorter than the distance between the secondary transfer nip portion 16 and the position where a toner image is formed by the image forming unit 20W arranged on the most downstream side.

The label roll paper 70 to which the toner image is transferred reaches the fixing unit 35 including two fixing belts including an upper roller and a lower roller that contact each other to form a fixing nip portion.
A halogen lamp or the like as a heat source is provided inside each fixing belt, and heat for melting and fixing the toner image is supplied to each fixing belt.

The label roll paper 70 is pinched and conveyed in the fixing nip portion of the fixing unit 35, and the toner image secondarily transferred to each label is pressed and heated to be fixed.
The label roll paper 70 on which the toner image is fixed is conveyed by the discharge rollers 36 (36a, 36b), and printing is completed.

As described above, the image forming apparatus 1 is configured to be capable of continuously forming toner images on the label of the label roll paper 70.
Next, the detection of the label roll paper 70 and the label pitch will be described.
FIG. 3 is an explanatory diagram of the gap type label roll paper in the embodiment, and FIG. 4 is an explanatory diagram of the sensor output in the embodiment.

The label roll paper 70a shown in FIG. 3 is a gap type label roll paper 70a in which a predetermined gap (label gap) is held between the labels 71, and FIGS. 3(a) and 4(a) show the label roll paper 70a. FIG. 3B is a side sectional view of the label roll paper 70a, and FIG. 3C is an enlarged view of a side cross section of the label roll paper 70a. 4C shows the waveform of the output signal level of the transmissive sensor light receiving unit 43b shown in FIG. 1 in the gap type label roll paper 70a shown in FIG. The waveform of the output signal level shown in FIG. 1 is the same for the transmissive sensor light receiving unit 42b.

5 is an explanatory diagram of a black mark type label roll paper in the embodiment, and FIG. 6 is an explanatory diagram of sensor output in the embodiment.

The label roll paper 70b shown in FIG. 5 is a black mark type label roll paper 70b in which a black mark 73 is printed on the back surface of a mount 72 corresponding to the label 71, and the label roll paper 70b shown in FIGS. 5 is a top view of the label roll paper 70b, FIGS. 5B and 6B are side sectional views of the label roll paper 70b, and FIG. 5C is an enlarged view of a side cross section of the label roll paper 70b. 6C shows a waveform of the output signal level of the reflective sensor 43a shown in FIG. 1 in the black mark type label roll paper 70b shown in FIG. The output signal level waveform shown in FIG. 1 is the same for the reflective sensor 42a.

It should be noted that the arrow B in FIGS. 3 to 6 indicates the medium transport direction.

In the present embodiment, as shown in FIGS. 3 and 5, the label roll papers 70 a and 70 b include a mount 72 and a plurality of labels 71 attached on the mount 72, and the label 71 is provided on the surface of the label 71. The toner image is transferred and printed.

The backing sheet 72 is formed of continuous long strip-shaped or tape-shaped paper, resin film, or the like, and is wound to form the label roll papers 70a and 70b.
The label 71 is a paper, a resin film, or the like that is releasably attached to the surface of the mount 72 by an adhesive or the like, and a plurality of labels 71 are attached side by side at predetermined intervals in the longitudinal direction (transport direction) of the mount 72. There is. The label 71 is used by peeling it from the mount 72.

The first type of gap type label roll paper 70a shown in FIG. 3 is obtained by pasting a paper, a resin film or the like having the same size as the mount 72 on the surface of the mount 72, and then part of it having a predetermined size and The label 71 is formed by die-cutting into a shape, and a margin portion (unnecessary portion) remains around the label 71. The label roll paper 70 a has the margins (hereinafter referred to as “label dregs”) removed, and label dregs remain between adjacent labels 71 (label gap) and around each label 71. Not not.

Further, as shown in FIG. 4C, the output signal of the transmissive sensor light receiving unit 43b has a higher light transmittance than that of the label 71 in the label gap portion where no label residue exists, so that the light receiving level rises and is output. In the label 71, on the other hand, the light transmittance of the label 71 is lower than that of the label gap portion, so that the light receiving level is lowered and the output voltage is lowered. Therefore, the position of the edge (edge) of the label 71 can be detected based on the output signal of the transmissive sensor light receiving unit 43b, and the label pitch LP can be determined based on the change time of the output signal and the transport speed of the label roll paper 70a. Can be calculated.

In this way, the transmissive sensor light receiving unit 43b detects the leading end of the label 71 attached to the label roll paper 70a in the medium transport direction based on the change in light transmittance, and calculates the label pitch LP.

In the second type of black mark type label roll paper 70b shown in FIG. 5, black marks 73 are printed on the back surface of the mount paper 72 in accordance with the edge of the leading end of the label 71 in the medium transport direction. The label roll paper 70b is a type in which it is not necessary to remove label residue because the black mark 73 detects the tip position of the label 71.

Further, as shown in FIG. 6C, the output signal of the reflection type sensor 43a has a lower light transmissivity than that of the mount 72 at the portion where the black mark 73 exists, so the light receiving level is lowered and output. On the other hand, the voltage decreases, and the light reflectance in the part of the mount 72 where the black mark 73 does not exist is higher than that in the part where the black mark 73 exists. Therefore, the light receiving level rises and the output voltage rises. Therefore, the position of the edge of the label 71 can be detected based on the output signal of the reflective sensor 43a, and the label pitch LP is calculated based on the change time of the output signal and the transport speed of the label roll paper 70b. can do.

In this way, the reflective sensor 43a detects the black mark 73 as the black mark provided at the position corresponding to the label of the label roll paper 70b based on the change in the light reflectance, thereby detecting the position of the label, The label pitch LP is calculated.

Next, the moving mechanism of the label pitch detecting sensor 43 shown in FIG. 1 will be described based on the explanatory view of the moving mechanism of the label pitch detecting sensor in the embodiment of FIG. FIG. 7A is a perspective view of the moving mechanism of the label pitch detecting sensor 43, and FIG. 7B is a side view of the moving mechanism of the label pitch detecting sensor 43.

In FIG. 7, the moving mechanism of the label pitch detection sensor 43 moves the label pitch detection sensor 43 in the label roll paper width direction (the medium width direction orthogonal to the medium conveyance direction) indicated by an arrow C in the drawing. Further, as described above, the label pitch detection sensor 43 selectively uses the transmissive sensor and the reflective sensor according to the type of label roll paper. In FIG. 7, the label pitch detection sensor 43 will be described as an example in which a reflective sensor is mounted.

The reflective sensor 43a is fixed to a frame serving as a support portion of the label pitch detection sensor 43, and a home position sensor shielding plate 44 is attached to the lower side of the frame.
The label pitch detection sensor 43 is connected to a spiral rotary shaft 48 and a main shaft provided so as to be parallel to the rotary shaft 48.

The rotary shaft 48 is connected to a label pitch detection sensor moving motor 47 via a gear and is rotatably supported.
The label pitch detection sensor moving motor 47 is a general-purpose stepping motor, and when it rotates, the spiral rotation shaft 48 rotates.

The label pitch detection sensor 43 moves in the width direction of the roll paper by being guided by the engaging main shaft as the screwed rotary shaft 48 rotates.
The home position sensor 45 is a general-purpose transmissive photocoupler, and is a sensor that is disposed on the end side in the axial direction of the rotary shaft 48 and that detects the position of the label pitch detection sensor 43. The home position sensor 45 can detect the position of the label pitch detection sensor 43 when the home position sensor shield plate 44 attached to the moving label pitch detection sensor 43 blocks the optical axis.

The sensor calibration plate 46 is disposed so as to be parallel to the rotary shaft 48, and the reflective sensor 43a determines the presence or absence of the label roll paper and the black mark. It is a reflector having. As shown in FIG. 7B, the sensor calibration plate 46 is arranged so as to face the reflective sensor 43a, detects the label roll paper 70 passing through the medium transport space 49 between the reflective sensor 43a, and the label. The black mark on the roll paper 70 is detected.

Since the label pitch is measured by selectively using the transmissive sensor and the reflective sensor according to the type of the label roll paper, the transmissive sensor light receiving unit is also fixed to the frame of the label pitch detection sensor 43 and the reflective sensor is used. It is adapted to move together with the sensor 43a. Further, the transmissive sensor light emitting portion is provided near the sensor calibration plate 46, and by rotating the spiral rotary shaft similarly to the movement of the reflective sensor 43a, the label roll is synchronized with the transmissive sensor light receiving portion. It can be moved in the paper width direction.

FIG. 8 is a block diagram showing the control arrangement of the image forming apparatus in the embodiment.

In FIG. 8, the image forming apparatus 1 is communicatively connected to a higher-level device 100 as an external device such as a host PC (Personal Computer). The image forming apparatus 1 has a command/image processing unit 2, an engine control unit 3, a paper information storage unit 4, a label pitch detection sensor position control unit 5, and an image position correction processing unit 6.

The command/image processing unit 2 is for generating image data to be formed on the label of the label roll paper based on the print data received from the upper level device 100. In addition, the command/image processing unit 2 notifies the engine control unit 3 of print start information in order to print the generated image data.

Upon receiving the notification of the print start information, the engine control unit 3 drives each motor, the LED 22, the high-voltage power supply unit (the image forming unit 20, the primary transfer unit, the secondary transfer unit, and the like illustrated in FIG. 1), Printing is performed by controlling the fixing unit 35 shown in FIG. The engine control unit 3 controls the LED 22 based on the image data to which the correction value of the image position correction processing unit 6 is fed back to expose the photoconductor 11 of the image forming unit 20 shown in FIG.

The paper information storage unit 4 stores paper information such as label roll form information and page information included in the print data received from the higher-level device 100.
Here, the label roll form information is information indicating the type of label roll paper such as continuous paper, die-cut label paper, and black mark paper, and any one of them is selected.

Further, the page information includes a label length (length of the label 71 in the medium transport direction shown in FIG. 3), a label gap length (interval between the labels 71 shown in FIG. 3), and a mount width (width of the mount 72 shown in FIG. 3). , And the page width (width of the label 71 shown in FIG. 3), which is treated as basic information for image forming position correction.

The label pitch detection sensor position control unit 5 as the detection unit movement control unit controls the label pitch detection sensor 43 shown in FIG. 7 to move in the label roll paper width direction based on the paper information stored in the paper information storage unit 4. It is a department. The label pitch detection sensor position control unit 5 controls the position of the label pitch detection sensor 43 and stores the information for controlling the position of the label pitch detection sensor 43, and the label pitch detection sensor 51. The label pitch detection sensor driving motor 52 for driving the movement motor 47 is controlled to move the label pitch detection sensor 43. Further, when the change in the sensor output signal of the home position sensor 45 is input to the home position detection unit 53, the label pitch detection sensor position control unit 5 causes the sensor position control/storage unit 51 to reference the reference position of the label pitch detection sensor 43. Is recognized, and the position of the label pitch detection sensor 43 in the label roll paper width direction is controlled as necessary (based on the paper information stored in the paper information storage unit 4).

The image position correction processing unit 6 corrects the position of the toner image formed on the intermediate transfer belt 12 shown in FIG. 1 based on the label interval in the medium transport direction measured by the label pitch detection sensor 43. It has a value storage unit 61, an image position correction value generation unit 62, a label pitch measurement processing unit 63, and a paper leading edge position detection unit 64.

The paper leading edge position detection unit 64 detects the leading edge position of the label of the label roll paper in the medium transport direction from the change in the output signal of the label pitch detection sensor 43.
The label pitch measurement processing unit 63 measures the label pitch from the information on the leading end position of the label detected by the paper leading end position detecting unit 64.

The image position correction value generation unit 62 calculates the correction value of the position where the image is formed by adding calculation processing such as averaging and correction of the prediction error from the label pitch measured by the label pitch measurement processing unit 63. is there.
The image position correction value storage unit 61 stores the latest correction value calculated by the image position correction value generation unit 62. The correction value stored in the image position correction value storage unit 61 is read by the command/image processing unit 2, and the command/image processing unit 2 generates image data by feeding back the correction value of the correction processing unit 6.

The image forming apparatus 1 includes a control unit such as a CPU (Central Processing Unit), and the entire operation is controlled by the control unit based on a control program (software) stored in a storage unit such as a memory.
In the image forming apparatus 1 configured as described above, the label pitch detection sensor position control unit 5 moves the label pitch detection sensor 43 to the center of the label roll paper in the medium width direction, and the image position correction processing unit 6 moves the medium width direction. The toner image formation position on the intermediate transfer belt 12 shown in FIG. 1 is corrected based on the label interval measured by the label pitch detection sensor 43 moved to the center of the label roll paper.

The operation of the above configuration will be described.

In the present embodiment, the label pitch detection sensor 43 shown in FIG. 7 is moved to the central portion in the width direction of the label roll paper based on the information stored in the paper information storage unit 4 shown in FIG. Performs control to realize label pitch measurement.

First, the detection and movement of the position of the label pitch detection sensor 43 shown in FIG. 7 will be described with reference to FIGS. 7 and 8 based on the explanatory view of the movement of the label pitch detection sensor in the embodiment of FIG. It should be noted that FIG. 9B shows an output signal of the home position sensor 45.

As shown in FIG. 9A, the frame of the label pitch detection sensor 43 is provided with a home position sensor shielding plate 44, and when the label pitch detection sensor 43 is arranged at a position corresponding to the home position sensor 45. As shown in FIG. 9B, the output signal level of the home position sensor 45 becomes the Low level. When the home position sensor shielding plate 44 shields the optical axis, the home position sensor 45 has a light transmittance of 0% and outputs a low level signal. The home position sensor 45 has a light transmittance of 100% and outputs a high level signal when the optical axis is not shielded by the home position sensor shielding plate 44.

The label pitch detection sensor position control unit 5 detects that the output signal of the home position sensor 45 has become Low level, and detects that the label pitch detection sensor 43 is arranged at the reference position (home position).

In the present embodiment, the reference position (home position) is set to the paper position reference surface SP side in the maximum paper-passable paper width range W, that is, the end portion on one side (for example, right side) of the label roll paper 70 in the transport direction. Set near the reference position. The label pitch detection sensor position control unit 5 sets P0 (position 0) when the label pitch detection sensor 43 is arranged at the reference position, and moves the label pitch detection sensor 43 in the label roll paper width direction indicated by an arrow C in the drawing. The position of the label pitch detection sensor 43 is controlled by controlling the number of pulses output to the label pitch detection sensor moving motor 47. Therefore, the label pitch detection sensor position control section 5 can control the position of the label pitch detection sensor 43 based on the information stored in the paper information storage section 4.

Next, referring to FIGS. 7, 8 and 9, the label pitch detection sensor movement processing performed by the image forming apparatus is performed according to the step indicated by S in the flowchart of the flow chart of the label pitch detection sensor movement processing in the embodiment of FIG. While explaining.

S1: The label pitch detection sensor position control unit 5 of the image forming apparatus 1 confirms that the label pitch detection sensor 43 is arranged at the reference position (home position) by the sensor position control/storage unit 51 and the home position detection unit 53. It is determined whether or not it is detected, and if it is detected (the output signal of the home position sensor 45 is at the Low level), the process proceeds to S3, and it is not detected (the output signal of the home position sensor 45 is High). If it is determined to be “level”, the process proceeds to S2.

S2: The label pitch detection sensor position control unit 5 drives the label pitch detection sensor moving motor 47 by the label pitch detection sensor moving motor driving unit 52 to move the label pitch detection sensor 43 to the reference position (home position) direction. The label pitch detection sensor 43 is moved, the process is returned to S1, and the label pitch detection sensor 43 is moved until the label pitch detection sensor 43 is arranged at the reference position (home position).

In this way, the label pitch detection sensor position control unit 5 performs the processing of S1 and S2, and performs the sensor position initial processing for arranging the label pitch detection sensor 43 at the reference position (home position).

Next, the image forming apparatus 1 performs a sensor movement process of moving the label pitch detection sensor 43 to the central portion of the label roll paper 70 in the width direction.

Here, it is assumed that the higher-level device 100 transmits print data to the image forming device 1.

S3: The image forming apparatus 1 receives the print data from the upper level apparatus 100. The image forming apparatus 1 stores paper information such as label roll form information and page information included in the print data received from the higher-level device 100 in the paper information storage unit 4.

S4: The label pitch detection sensor position control unit 5 acquires the label roll form information from the paper information stored in the paper information storage unit 4.

S5: The label pitch detection sensor position control unit 5 determines whether the label roll paper to be printed is a black mark paper or a die cut label paper based on the acquired label roll form information, and determines the black mark paper or the die cut label paper. If it is determined to be, the process proceeds to S7, and if it is determined to be plain paper which is not black mark paper or die-cut label paper or continuous paper, the process proceeds to S6.

S6: The label pitch detection sensor position control unit 5, which has determined that it is plain paper or continuous paper that is not black mark paper or die-cut label paper, does not require image position correction because the label interval does not exist, and the label pitch detection sensor 43 uses the reference position ( After confirming that the label pitch detection sensor 43 is placed at the home position), the present process is terminated without moving the label pitch detection sensor 43.

S7: The label pitch detection sensor position control unit 5, which has determined that the paper is the black mark paper or the die-cut label paper, converts the paper width information (medium width information) from the paper information stored in the paper information storage unit 4 into the mount width information of the page information. ) As.

S8: The label pitch detection sensor position control unit 5 controls the driving amount of the motor 47 for moving the label pitch detection sensor according to the acquired paper width information, and moves the label pitch detection sensor 43 from the reference position (home position) to the label roll. It moves to the center of the paper (paper) in the width direction. Specifically, the label pitch detection sensor position control unit 5 determines the distance to the central portion (central portion CT shown in FIG. 9) in the width direction of the label roll paper, that is, the label roll paper width based on the acquired paper width information. The half length is calculated, and the label pitch detection sensor moving motor drive unit 52 drives the label pitch detection sensor moving motor 47 based on the number of pulses corresponding to the distance to the central portion, and the label pitch detection sensor 43. To the center of the label roll paper in the width direction.

In this way, the image forming apparatus 1 performs the sensor movement process.

In this embodiment, the label pitch detection sensor 43 is moved to the center in the width direction of the label roll paper based on the paper width information received from the higher-level device 100, but it has a label pitch detection sensor moving mechanism. Therefore, the label pitch detection sensor 43 may detect the width of the label roll paper.

In this case, the label pitch detection sensor 43 is moved in the width direction of the label roll paper while the label roll paper is primarily conveyed to a position where it can be detected by the label pitch detection sensor 43, and both ends of the label roll paper in the width direction are moved. The paper width information can be obtained by detecting the set and detecting the width of the label roll paper.

Further, the paper insertion portion may be provided with two paper guides that come into contact with both end portions of the label roll paper in the width direction, and the paper width information may be obtained from the position of the paper guide (space between the paper guides).

Next, the image position correction processing for correcting the image formation position based on the detection result of the label pitch detection sensor will be performed in accordance with the step represented by S in the flowchart of the flow chart of the image formation position correction processing in the embodiment of FIG. , FIG. 7, FIG. 8 and FIG.

S101: Similar to S3 shown in FIG. 10, the image forming apparatus 1 receives print data from the upper level apparatus 100. The command/image processing unit 2 starts generation of image data based on the print data received from the upper level device 100.

S102: The command/image processing unit 2 acquires the latest correction value held in the image position correction value storage unit 61 of the image position correction processing unit 6 as the label pitch correction value.

S103: The command/image processing unit 2 adds the acquired correction values, and determines the toner image length in the medium transport direction (toner image data length of the margin portion corresponding to the label gap), that is, the image forming position.

Here, the command/image processing unit 2 generates image data based on the determined toner image length, and the engine control unit 3 drives various motors to start the conveyance of the label roll paper and also the LED head. 22 is driven, and image formation by the image forming unit 20 is also started. Therefore, by forming the toner image on the intermediate transfer belt 12 based on the determined toner image length, the position where the toner image is formed is corrected.

S104: While the command/image processing unit 2 successively generates continuous image data based on the toner image length, the paper leading edge position detection unit 64 of the image position correction processing unit 6 changes the output signal of the label pitch detection sensor 43. Then, the label tip position of the label roll paper in the medium transport direction is detected, and the label pitch measurement processing unit 63 measures the label pitch from the information of the label tip position detected by the paper tip position detection unit 64.

The image position correction processing unit 6 determines whether or not the label pitch measurement value has been acquired by the label pitch measurement processing unit 63. If it is determined that the label pitch measurement value has been acquired, the process proceeds to S106. The process moves to S105.

S105: If the image position correction processing unit 6 determines that the label pitch measurement value has not been acquired, the command/image processing unit 2 continues to use the immediately previous correction value and determines the toner image length in the medium transport direction. That is, the image forming position is determined, and the process proceeds to S108.

S106: When the image position correction processing unit 6 determines that the label pitch measurement value has been acquired, the image position correction value generation unit 62 averages the label pitch measured by the label pitch measurement processing unit 63 and calculates the prediction error. A correction value for a position forming an image is calculated by performing calculation processing such as correction, and the latest correction value is updated and held in the image position correction value storage unit 61 as a label pitch correction value at any time.

S107: The command/image processing unit 2 acquires the latest correction value from the image position correction value storage unit 61, and uses the updated correction value to determine the toner image length in the medium transport direction, that is, the image forming position.

S108: The command/image processing unit 2 determines whether or not the printing of the received print data is completed. If it is determined that the printing of the received print data is not completed, the process returns to S104, and the label pitch until the printing of the print data is completed. The image forming position is corrected while feeding back the correction value. On the other hand, if it is determined that the printing of the received print data has been completed, this processing ends.

Next, a comparative example will be described based on an explanatory view of the paper detection sensor position in the comparative example of FIG. 12, a model diagram of label pitch measurement in the comparative example of FIG. 13, and an explanatory diagram of margin variation in the comparative example of FIG. To do.

In the case of a label roll paper in which a plurality of labels are pasted at a predetermined pitch on a continuous strip-shaped roll paper as a recording medium, it is between the pitch of the toner image formed on the intermediate transfer belt and the pitch of the label on the label roll paper. If there is a minute error, when toner images are continuously formed on the label, the position of the toner image formed on each label gradually shifts with respect to the label.

In order to deal with such a problem, label roll paper on which a black mark is printed is used at a position corresponding to the leading end of each label on the back surface of the label roll paper which is the mount. By forming a toner image while detecting the interval between the two black marks as a label pitch by a detection means such as a sensor, the pitch of the toner image and the pitch of the label are made to coincide, and the position of the toner image formed on each label is adjusted. It is possible to prevent the slippage.

The label printer as the image forming apparatus of the comparative example determines the position by pushing the label roll paper deep into the holder shaft and abutting the label roll paper on the side surface of the holder in order to securely attach the label roll paper at an appropriate position. Is common.

As shown in FIG. 12, in the label printer, since the position reference of the label roll paper 250 is the side surface (the right side paper position reference face 201 in the medium transport direction indicated by the arrow B) of the end face of the label roll paper, a black mark is displayed. A detection sensor 202 for detecting the leading edge of the label roll sheet 250 and the sheet 203 is also arranged near the sheet position reference plane 201. By disposing the detection sensor 202 near the paper position reference surface 201, the label roll paper 250 can be detected regardless of the label width.

The label printer prints on the label 251 attached to the strip-shaped label roll paper 250. The printed label 251 is not necessarily cut for each label 251, and may be continuously printed without being cut. The printed label roll paper 250 is rewound into a roll shape by a winder. Things are common.
Conveyance of a long sheet such as the label roll sheet 250 is different from that of a standard sheet (for example, A3 size) such as a so-called office printer that is skewed because a belt-shaped continuous sheet is conveyed in units of several meters. It is easy to occur.

Therefore, the paper guide position is adjusted according to the width of the label roll paper 250, the meandering space on the opposite side of the paper position reference plane 201 is restricted, and the label roll paper 250 is biased toward the paper position reference plane 201 while applying tension. A means for minimizing the meandering of the label roll paper 250, such as transporting while applying such a force, is used.
However, if the regulation of meandering is strengthened, the side surface of the label roll paper 250 may be torn, the label roll paper 250 may be clogged, or the label 251 may be peeled off, and it is very difficult to convey the label roll paper 250 that does not meander. Is.

Due to the meandering of the label roll paper 250, the position of the toner image formed on each label may deviate from the label.

On the other hand, in an inkjet printer, a thermal printer, or an electrophotographic printer that directly transfers a toner image onto paper, the image formation timing may be determined after detecting the black mark 203 or the edge of the label 251 to be image-formed. Since it is possible, the label 251 detected by the detection sensor 202 is the image forming target label 251, the position of the label 251 and the position of the image can be substantially matched, and even if the label roll paper 250 skews due to meandering, the label 251 There is little influence on the printing on 251.

However, in the image forming apparatus of the intermediate transfer type as in this embodiment, the toner image is secondarily transferred to the label roll paper 250 at the secondary transfer portion after the LED head as the exposure means writes the latent image on the photoconductor. It takes a very long time to reach this point, which is about 100 mm. Moreover, the length of each label in a general label roll paper is about 100 mm.

Therefore, when the pitch of the black mark 203 or the gap of the label 251 is detected by the detection sensor 202 arranged near the secondary transfer portion, at the time when the pitch of the label 251 is measured, the label 251 and the label 251 and later are already detected. The toner images to be transferred onto the several labels 251 have been transferred onto the intermediate transfer belt.

That is, the predictive control is performed in which the black mark 203 or the edge of the label 251 is detected, the position of the toner image to be transferred is predicted, and the exposure timing of the LED head is adjusted.

Therefore, the length from the detected label 251 to the beginning of the next label 251 (label pitch) is accurately measured, and the measured label pitch is fed back as a correction value to match the length of the toner image with that of the label 251. There must be. Since the variation in the measurement of the label pitch for each of the labels 251 affects the correction value to be fed back, the measurement information of the label pitch with high accuracy and few fluctuation factors is required.

FIG. 13 is a model diagram imagining the arrangement of the detection sensor 202 on the paper position reference surface side, the meandering of the label roll paper 250, and the measurement of the label pitch when the label roll paper 250 meanders.

The label roll paper 250 conveyed in the medium conveyance direction indicated by the arrow B is meandered to some extent, and the black mark 203 of the label 251 passing on the detection sensor 202 and the skewness of the edge are changed. .. Therefore, the measured value of the label pitch also includes the amount of inclination variation, and the average value of the measured value of the label pitch occurs.

FIG. 14 shows changes in the toner image forming position when the label pitch is detected by the detection sensor 202 arranged on the paper position reference surface side as shown in FIG.

FIG. 14A shows a change in the average value of the label pitch measurement results when printing is performed twice for cutting a page in which 20 labels are linked. The amount of variation is 0.2 mm, which is an extremely small amount of variation, but the amount of margin at the leading edge of the label (the amount of upper margin) in the medium transport direction when the toner image forming position is fed back with the correction value based on the measured value of the label pitch. 14B, as shown in FIG. 14B, the maximum change is about 1 mm, and the positional deviation between the label and the image becomes large.

As described above, in the comparative example, since the label pitch is detected by the detection sensor 202 arranged on the paper position reference surface side, the misalignment between the label and the image becomes large.

FIG. 15 is an explanatory diagram of the inclination of the label tip in the embodiment. FIG. 15 shows a change in the inclination of the label tip due to meandering when a label roll paper in which labels are linked is printed, and specifically, printing is performed three times by cutting 20 pages in which labels are linked, for a total of 60 sheets. When the label is printed, the amount of the leading edge margin of the label in the medium transport direction is measured.

From the results shown in FIG. 15, it can be seen that the inclination of the label leading edge, which initially had a small amount of skew feeding at the start of printing, gradually increased and then returned to a state of less skew. Here, when the label pitch is detected by arranging the detection sensor in the area SD near the paper position reference plane SP, the fluctuation of the label pitch becomes large, but the detection sensor is arranged at the central portion CT in the width direction of the label roll paper 70. Then, when the label pitch is detected, it can be seen that the fluctuation of the label pitch is small.

FIG. 16 is a model diagram of the measurement of the label pitch in the embodiment, and shows a state in which the detection sensor 43 is arranged at the central portion CT in the width direction of the label roll paper shown in FIG. 15 to measure the label pitch.
As described above, in this embodiment, the detection sensor 43 is arranged at the central portion CT in the width direction of the label roll paper 70 to detect the label pitch.

FIG. 17 is an explanatory diagram of the margin variation in the embodiment. As shown in FIG. 16, the toner image when the label pitch is detected by the detection sensor 43 arranged at the central portion CT in the width direction of the label roll paper 70. Represents the change in the formation position of.

FIG. 17A shows the fluctuation of the average value of the label pitch measurement results when printing is performed twice for cutting the page in which 20 labels are linked. Compared to the case where the detection sensor is placed on the paper position reference surface side, the variation in the average value of the label pitch measurement results is smaller, and as a result, the toner image formation position is determined by the correction value based on this label pitch measurement value. The change in the leading edge margin amount (upper margin amount) of the label in the medium conveyance direction when fed back is small as shown in FIG. Specifically, the front end margin amount when the detection sensor is arranged on the side of the paper position reference plane is a change of about 1 mm, but the front end when the detection sensor is arranged in the central portion in the width direction of the label roll paper 70. The margin amount is improved to a change of about 0.5 mm to 0.6 mm.

As described above, in this embodiment, the detection sensor 43 for detecting the label pitch is arranged in the central portion in the width direction of the label roll paper 70 to measure the label pitch, and the toner is corrected with the correction value based on the measured value of the label pitch. By feeding back the image forming position, the deviation of the toner image forming position from the predetermined position can be suppressed even when the label roll paper 70 meanders.

As described above, in this embodiment, the label pitch detection sensor position control unit of the image forming apparatus moves the detection sensor that detects the label pitch to the center of the continuous medium in the medium width direction, and the image position correction processing unit moves the medium. By correcting the position of the developer image based on the label interval measured by the detection sensor that has moved to the center of the continuous medium in the width direction, the deviation of the formation position of the developer image when the continuous medium meanders is corrected. The effect that it can be suppressed is obtained.

In this embodiment, the image forming apparatus has been described as a color printer, but the present invention is not limited to this and may be a monochrome printer.

1 image forming apparatus 2 command/image processing unit 3 engine control unit 4 paper information storage unit 5 label pitch detection sensor position control unit 6 image position correction processing unit 12 intermediate transfer belt 15Y, 15M, 15C, 15K, 15W primary transfer roller 16 Secondary transfer nip part 20 (20Y, 20M, 20C, 20K, 20W) Image forming unit 30 Holder 33 Cutter unit 34 Conveying roller 35 Fixing unit 42 Cut position detecting sensor 43 Label pitch detecting sensor 43a Reflective sensor 43b Transmissive sensor Light receiving part 43c Transmissive sensor light emitting part 44 Home position sensor shielding plate 45 Home position sensor 46 Sensor calibration plate 47 Label pitch detection sensor moving motor 48 Rotating shaft 51 Sensor position control/storage part 52 Label pitch detection sensor moving motor drive part 53 Home Position Detection Unit 61 Image Position Correction Value Storage Unit 62 Image Position Correction Value Generation Unit 63 Label Pitch Measurement Processing Unit 64 Paper Edge Position Detection Unit 70 Label Roll Paper 71 Label 72 Mount 73 Black Mark

Claims (6)

A medium carrying means for carrying the continuous medium on the basis of one side in the medium carrying direction of the continuous medium provided with a plurality of labels,
An image forming unit that forms a developer image on the intermediate transfer member,
A transfer unit for transferring the developer image formed on the intermediate transfer member to a label of a continuous medium conveyed by the medium conveying unit,
A detection unit that is arranged upstream of the transfer unit in the medium conveyance direction and detects the label of the continuous medium conveyed by the medium conveyance unit;
A detection unit movement control unit for moving the detection unit in the medium width direction orthogonal to the medium conveyance direction,
An image position correction unit that corrects the position of the developer image formed on the intermediate transfer member based on the label interval in the medium transport direction measured by the detection unit,
Have
The detection unit movement control unit moves the detection unit to the center of the continuous medium in the medium width direction,
The image forming apparatus is characterized in that the image position correcting unit corrects the position of the developer image based on the label interval measured by the detecting means moved to the center of the continuous medium in the medium width direction. The image forming apparatus according to claim 1,
The detection unit movement control unit moves the detection unit from a reference position on one side in the medium transport direction of the continuous medium to the center of the continuous medium in the medium width direction based on the medium width information received from an external device. A characteristic image forming apparatus. The image forming apparatus according to claim 1, wherein:
The image forming apparatus, wherein the detection unit is a light transmission type sensor, and detects the leading end of the label attached to the continuous medium in the medium transport direction based on the change in the light transmittance. The image forming apparatus according to claim 1, wherein:
An image characterized in that the detection means is a light reflection type sensor, and detects the position of the label by detecting a black mark provided at a position corresponding to the label of the continuous medium based on the change of the light reflectance. Forming equipment. The image forming apparatus according to any one of claims 1 to 4,
An image forming apparatus, wherein a distance between the detecting unit and the transfer unit is shorter than a distance between a position where a developer image is formed in the image forming unit and the transfer unit. The image forming apparatus according to any one of claims 1 to 5,
The image position correction unit may store a correction value based on the label interval value measured by the detection unit in the storage unit at any time to update the correction value, and correct the position of the developer image based on the updated correction value. A characteristic image forming apparatus.

Images