JP2008044211A - Image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming device which can attain a desired length of sheet as an output result of image formation, even in the case of environmental changes such as temperature or the like. <P>SOLUTION: The image forming device comprises a carrying roller 53 for carrying the roll paper accommodated in a paper feeding device to an image forming means which carries out image forming treatment, a cutter 60 for cutting the roll paper carried with the carrying roller 53, a temperature sensor 70 for sensing the temperature in the vicinity of the carrying roller 53, and a control unit 110 for controlling the cut timing of the roll paper with the cutter 60 corresponding to the detected temperature indicating the temperature detected by the temperature sensor 70. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image forming apparatus that transports roll paper stored in a paper feeder toward an image forming unit by a transport roller, and cuts the transported roll paper to a predetermined length by a cutting unit.

  2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine that copies a large document such as a drawing, and a printer that prints document information corresponding to a large document such as a drawing, a copying machine and a printer that use a normal size cut sheet Unlike an image forming apparatus such as the above, a roll paper in which a long paper is wound is attached to a paper feeding unit, the roll paper is cut into a predetermined length, and the cut paper (recording) is recorded. An image is formed on paper.

  The storage unit (roll paper feeding device) includes a transport roller that transports the roll paper stored therein, and a cutter that cuts the paper transported (sent out) by the transport roller. A rubber roller is generally used as the transport roller.

  As the cutting length of the paper to be sent out of the roll paper stored in the roll paper feeding device (the length from the front end of the paper to the end to be cut), the paper sending length is determined based on the rotation information of the transport roller. A method of setting is used. For example, the cut length of the fed paper is determined based on the relationship between the outer diameter of the transport roller and the number of pulse signals supplied to the motor that rotationally drives the transport roller.

  As is well known, an image forming apparatus including the above-described image forming apparatus is also used in an environment such as low temperature and low humidity or high temperature and high humidity. In such an environment, the conveyance of a sheet such as a cut sheet is affected. Therefore, an environmental measure in consideration of temperature and humidity is required.

As an image forming apparatus that takes environmental measures against low temperature and low humidity and high temperature and high humidity, the one disclosed in Patent Document 1 is known.
Japanese Patent Laid-Open No. 7-61691

  By the way, when the rotation information of the conveyance roller is used in determining the feed length of the roll paper, it is a condition that the outer diameter of the conveyance roller is constant.

  However, the outer diameter of the rubber roller used in the conveying roller provided in the roll paper feeding device in the conventional image forming apparatus is slightly changed due to thermal expansion accompanying a change in environment such as temperature. There is a problem.

  In addition, some roll paper feeding devices are equipped with a dehumidifying heater, and the temperature change in the roll paper feeding device in which the heater is turned on becomes large (the heater is turned off). The temperature becomes higher compared to the case), and accordingly, the change in the outer diameter of the transport roller also becomes larger (the outer diameter of the transport roller becomes larger than in the case where the heater is off). There's a problem.

  As described above, the change in the outer diameter of the transport roller accompanying the change in the environment such as temperature has a small effect when the paper after cutting is short (when the paper length is short), but when the paper after cutting is long (long) In the case of scale paper), the amount of change in the outer diameter of the transport roller is accumulated, and as a result, the determination of the paper feed length (paper length) is greatly affected. In other words, regarding paper (long paper) output as an image formation result, even when a paper (long paper) having the same length (length in the sub-scanning direction) is desired, it responds to changes in the environment. As a result, the length of the paper varies.

  Furthermore, since the friction coefficient of the surface of the rubber roller changes due to environmental changes, variations in the paper feed length (paper length) also occur due to the influence.

  When the technique disclosed in Patent Document 1 is applied to the roll paper conveyance process by the conveyance roller, that is, the conveyance speed of the roll paper by the conveyance roller is changed according to a change in temperature (environment). For example, when the image is formed on the roll paper that is being conveyed via the conveyance roller by the image forming unit that performs the image forming process, the roll paper by the conveyance roller is used. Control for associating the sheet conveying speed with, for example, the sheet conveying speed in the image forming unit must be performed. However, it is extremely difficult to perform such control.

  Accordingly, the present invention provides an image forming apparatus capable of setting the length of a sheet output as an output result of image formation to a desired length even when the environment such as temperature changes. Objective.

  In order to solve the above-described problem, the image forming apparatus according to the first aspect of the present invention includes a conveyance roller that conveys the roll paper accommodated in the sheet feeding device toward an image forming unit that performs an image forming process, The cutting means for cutting the roll paper conveyed by the conveying roller, the temperature detecting means for detecting the temperature in the vicinity of the conveying roller, and the cutting according to the detected temperature indicating the temperature detected by the temperature detecting means. Control means for controlling the cutting timing of the roll paper by means.

  According to a second aspect of the present invention, in the first aspect of the present invention, when the detected temperature is lower than a reference temperature, the control means determines the cutting timing in the state of the detected temperature. When the detected temperature is higher than the reference temperature, the cutting timing in the detected temperature state is set to be higher than the cutting timing in the reference temperature state. It is also characterized by making it faster.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the control unit is configured to perform cutting timing based on the detected temperature, rotation information of the transport roller, and temperature correction information related to the rotation information. And controlling the cutting means to cut the roll paper based on the information indicating the obtained cutting timing.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects of the present invention, the transport roller rotates following the rotation of a pulse-controlled motor. The means obtains a pulse number indicating the number of pulse signals to be provided to the motor as information indicating a cutting timing based on the detected temperature, the rotation information of the transport roller, and the temperature correction information related to the rotation information. The cutting means is controlled to cut the roll paper based on the obtained number of pulses.

  The invention according to claim 5 is the invention according to claim 3 or 4, wherein the rotation information of the transport roller is obtained based on the outer diameter information of the transport roller, and the transport per predetermined unit time. It is information indicating the paper length of the roll paper conveyed according to the rotation of the roller.

  The invention according to claim 6 is the invention according to any one of claims 3 to 5, wherein the temperature correction information is a rotation of the transport roller per predetermined unit time in the state of the detected temperature. Correction value for correcting the paper length of the roll paper transported according to the rotation to the paper length of the roll paper transported according to the rotation of the transporting roller per predetermined unit time in a reference temperature state It is characterized by being.

  According to the present invention, even when the environment such as the temperature in the vicinity of the roll paper changes, the length of the paper that is obtained by cutting the roll paper and output as an image formation result can be set to a desired length. it can. Thereby, even for a plurality of sheets output in different environments, variations in the length of each sheet (length in the sub-scanning direction) can be suppressed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiment, and the repetitive description thereof will be omitted.

  FIG. 1 is a perspective view showing an external appearance of an image forming apparatus according to an embodiment of the present invention.

  The image forming apparatus 1 includes an image forming apparatus main body 2 that executes image forming processing, and a housing 3 that houses a roll paper feeding device. The image forming apparatus 1 has a copying function, a printer function, and a scanner function, and fulfills the function of an image forming apparatus as a so-called multifunction machine.

  FIG. 2 shows an AA cross section of the image forming apparatus 1 shown in FIG.

  As shown in FIG. 2, the casing 3 accommodates a roll paper feeding device 20 that accommodates the roll paper 40 and a roll paper feeding device 30 that accommodates the roll paper 41.

  Here, the roll papers 40 and 41 are roll papers of each size from A0 to A3, for example, and may be roll papers of different sizes or roll papers of the same size. Here, it is assumed that the roll paper 40 is an A0 size roll paper and the roll paper 41 is an A1 size roll paper.

  The roll paper feeding device 20 pulls out the paper from the accommodated roll paper 40 and conveys the drawn paper toward the image forming unit 10 of the image forming apparatus main body 2 and on the downstream side thereof. And a cutter 60 for cutting the sheet fed by the transport roller unit 50. Similarly, the roll paper feeding device 30 also includes a transport roller unit 42 and a cutter 43.

  The casing 3 has a predetermined position in the vicinity of the roll paper feeding device 20, preferably a predetermined position corresponding to the vicinity of the arrangement position of the conveying roller unit 50, in the vicinity of the roll paper feeding device 20 (of the conveying roller unit 50. A temperature sensor 70 for detecting the temperature in the vicinity of a conveyance roller (to be described later) is provided. A detected temperature (temperature value) indicating the temperature detected by the temperature sensor 70 is input to the control unit 110 described later. Similarly, a temperature sensor 80 is disposed in the housing 3 at a predetermined position near the roll paper feeding device 30.

  Here, a paper feed roller 4 that feeds the paper transported by the transport roller unit 50 toward the image forming apparatus main body 2 is disposed in the transport path between the roll paper feeding device 20 and the image forming apparatus main body 2. It is installed. A paper feed roller 5 that feeds the paper transported by the transport roller unit 42 toward the image forming apparatus main body 2 is disposed in the transport path between the roll paper feeding device 30 and the image forming apparatus main body 2. Has been. Note that the paper fed from the roll paper feeding device 30 is conveyed toward the image forming apparatus main body 2 via the paper feeding roller 5 and the paper feeding roller 4.

  In the image forming apparatus main body 2, the scanner unit 11 scans an image of a document (long document) such as a large drawing and outputs the scanning result to the image forming unit 10. Further, the sheet conveyed from the housing 3 side is conveyed to the image forming unit 10 via the sheet feed roller 6 disposed in the image forming apparatus main body 2.

  The image forming unit 10 includes a photoconductor 12, a developing device 13, and a transfer unit 14, and forms an electrostatic latent image on the photoconductor 12 based on the result of scanning by the scanner unit 11, and then the developing device 13. As a result, the electrostatic latent image is formed (developed) as a toner image, and the toner image is further transferred by the transfer unit 14 to the sheet conveyed through the sheet feed roller 6. That is, the image forming unit 10 performs a so-called electrophotographic process.

  The toner image transferred to the paper in this way is fixed to the paper by the fixing device 15 when the paper passes through the fixing device 15. The sheet on which the toner image is fixed is discharged to the discharge port 17 via the discharge roller 16.

  FIG. 3 shows the configuration of the transport roller unit 50 of the roll paper feeder 20.

  As illustrated in FIG. 3, the transport roller unit 50 includes a motor 51, a gear train 52, a transport roller 53, and an idler roller 54.

  The conveyance roller 53 is a rubber roller having a shaft. The motor 51 is connected to the transport roller 53 via the gear train 52 and drives the transport roller 53. In the present embodiment, the motor 51 is a stepping motor whose rotation is controlled by pulse control. The idler roller 54 is disposed so as to be pressed against the conveying roller 53 by a biasing means (not shown).

  FIG. 4 shows the configuration of the control system of the roll paper feeding device in the image forming apparatus 1.

  The control system 100 corresponds to the roll paper feeder 20, and the control system 200 corresponds to the roll paper feeder 30.

  In the control system 100, the control unit 110 includes a CPU (central processing unit) 111, a ROM (read only memory) 112, and a RAM (optional read / write memory) 113, and these components are used to generate an image. The motor driver 120 and the cutter 60 are controlled under the control of the controller 300 provided on the forming apparatus main body 2 side. Further, the control unit 110 acquires a detected temperature in the vicinity of the roll paper feeding device 20 (that is, in the vicinity of the conveyance roller 53) detected by the temperature sensor 70, and controls the cutting timing of the roll paper by the cutter 60 based on the detected temperature. To do.

  In the control unit 110, the ROM 112 is referred to (1) for controlling the cutting timing of the roll paper by the cutter 60 according to the temperature change in the vicinity of the roll paper feeding device 20 (near the conveyance roller 53), which will be described later. (2) Parameters such as the outer diameter of the transport roller at the reference temperature, the motor step angle, the reduction ratio by the gear train, etc., or the roll paper feed length described later based on these parameters, (3 ) A predetermined processing program including a control program corresponding to a processing procedure (see FIG. 8) to be described later for controlling the cutting timing is stored.

  The RAM 113 is assigned a storage area for storing the detected temperature (temperature value) output from the temperature sensor 70 and a work area used for predetermined data processing such as obtaining the cutting timing by the CPU 111.

  The CPU 111 executes predetermined data processing including processing relating to the following (1) to (3) paper feeding.

  (1) Document size (length in the main scanning direction and length in the sub-scanning direction) designated from the controller 300, detected temperature from the temperature sensor 70, and roll paper feed length information stored in the ROM 112 (or The cutting timing is obtained based on the above parameters).

  (2) A start instruction signal indicating a motor drive start instruction is output to the motor driver 120.

  (3) Based on the number of pulse signals from the motor driver 120, a stop instruction signal indicating a motor drive stop instruction is output to the motor driver 120, and a cutting instruction signal indicating that the sheet should be cut is output to the cutter 60. .

  The control unit 110 also includes a counter (not shown) that counts the number of received pulse signals when receiving the pulse signals output from the motor driver 120.

  The motor driver 120 generates a pulse signal (pulse signal for driving the motor) to be supplied to the motor 51 under the control of the control unit 110, and outputs this pulse signal to the motor 51 and also outputs it to the control unit 110. To do.

  Since the control system 200 has the same configuration and function as those of the control system 100 described above, detailed description of the configuration and function is omitted here. In FIG. 4, the configuration of the control system 200 is omitted.

  Next, determination of the cutting timing of the control unit 110 will be described.

  Here, determining the cutting timing means determining the feed length (hereinafter referred to as “paper length”) L of the roll paper 40 conveyed by the conveyance roller 53 rotated by the rotation drive of the motor 51. To do. This sheet length L corresponds to the length of the sheet after cutting that is output as the image formation result (length in the sub-scanning direction).

  In the present embodiment, an example will be described in which the paper length is set based on the number of pulse signals supplied to the motor 51 in the roll paper feeding device 20.

When one pulse signal is supplied to the motor 51. The delivery length (hereinafter referred to as “unit paper length”) α of the roll paper 40 transported by the transport roller 53 per pulse is D, the outer diameter of the transport roller 53, the step angle of the motor 51 is θ, and the gear. When the reduction ratio in the column 52 is n, the following equation 1 is calculated.
(Equation 1)

    α = (D × π) × (θ / 360) × (1 / n)

  Here, since a pulse signal having a predetermined frequency (or cycle) is supplied to the pulse-controlled motor 51, “per pulse” is defined as “per cycle”, that is, “per predetermined unit time”. be able to.

  Accordingly, the unit paper length α of the roll paper transported per pulse is obtained based on the outer diameter of the transport roller, and the paper length of the roll paper transported according to the rotation of the transport roller per predetermined unit time. It can be said that (unit paper length) α. Further, the unit paper length α is obtained by rotation of the transport roller, and thus can be said to be rotation information of the transport roller.

When the unit paper length α is obtained by calculating the above equation 1, the number (pulse number) P of pulse signals to be supplied to the motor 51 necessary for obtaining the paper length L is the following equation 2. It is calculated by computing.
(Equation 2)

    P = L / α

  That is, the sheet length L of the sheet conveyed when the motor 51 is rotated by the number of pulses P obtained by calculating the number 2 is obtained. In this case, the paper length L matches the target length of the paper output as the image formation result (hereinafter referred to as “target paper length”).

  Here, the target paper length is, for example, the length of a long document of A0 size or A1 size (length in a direction corresponding to the sub-scanning direction) in the case of image formation at the same magnification.

  Incidentally, the unit sheet length α obtained by calculating the above equation 1 may be considered as a constant under a constant temperature environment, but in reality, the conveyance roller 53 caused by thermal expansion due to a difference in environment (temperature). Due to the change in the outer diameter and the change in the friction coefficient, the number is not constant.

  For this reason, in a state where an environmental change has occurred, the sheet length L of each of the plurality of sheets actually output as the image formation result is not constant and varies.

  That is, depending on the temperature, the relationship “paper length L ≠ target paper length” may be established. For example, when three long originals are copied, if the temperatures at the time of copying differ, There may be a case where the relationship of “first sheet length L ≠ second sheet length L ≠ third sheet length L” is established.

  Therefore, in the present embodiment, the temperature sensor 70 provided in the housing 3 detects the temperature in the vicinity of the roll paper feeding device 20 (particularly in the vicinity of the conveyance roller 53), and the unit paper length α based on the detected temperature. A correction value is added to the above, and the number of pulses P is obtained based on the corrected unit paper length α.

That is, the number of pulses P required to obtain the paper length L can be obtained by calculating the following equation 3 when the correction value for the unit paper length α, that is, the temperature correction value is δ.
(Equation 3)

    P = L / (α−δ)

  As shown in Equation 3, the sheet length L is set to a desired length by correcting the number of pulses P using the temperature correction value δ so as to be obtained by calculating Equation 2, that is, correcting the cutting timing. can do. As a result, the length of the paper output as the image formation result becomes the target paper length.

  Here, the cutting timing is the time when the rotation operation (rotation drive operation) of the motor to which the pulse signal for the number of pulses P is supplied ends (the rotation operation of the transport roller that rotates following the rotation of the motor is completed). Time).

  When the cutter 60 cuts the roll paper at this cutting timing, the paper length L of the cut paper becomes the target paper length.

  In the following description, the cutting timing is described as the number of pulses (pulse number P) of the pulse signal supplied to the motor. However, the original meaning is the time when the rotation operation of the motor (rotation operation of the conveying roller) based on the pulse signal for the number of pulses P is completed as described above.

  When the unit paper length α is a constant value, the longer the target paper length, the larger the difference between the paper length L and the target paper length (which causes a large variation), while the temperature environment changes. If the unit paper length α is corrected in accordance with the corrected unit paper length α and the number of pulses P, that is, the cutting timing is corrected using the corrected unit paper length α, the variation in the paper length L can be maintained even if the target paper length is increased. It is possible to suppress the sheet length L to be the target sheet length.

  For example, when three long originals are copied, even if the temperatures at the time of copying differ, “target paper length = first paper length L = second paper length L = third paper length L” Can be satisfied.

  From the above, the temperature correction value (temperature correction information) δ is the length of the roll paper conveyed (according to the rotation of the conveyance roller per pulse (per predetermined unit time) in the detected temperature state (per unit time)). In order to correct the unit paper length α) to the paper length (unit paper length α) of the roll paper conveyed according to the rotation of the conveyance roller per pulse (per predetermined unit time) in the state of the reference temperature. It can be said that this is a correction value.

  FIG. 5 shows information (graph) representing the relationship between the sheet length L and the pulse number P of the sheet in each environment (each temperature) state.

  Here, the line segment indicated by the symbol L0 indicates the relationship between the sheet length of the sheet at normal temperature and the number of pulses, and the line segment indicated by the symbol L1 indicates the relationship between the sheet length of the sheet at low temperature and the number of pulses. The line segment indicated by the symbol L2 indicates the relationship between the sheet length of the sheet and the number of pulses at a high temperature.

  Also, the unit sheet length of the sheet conveyed per pulse at normal temperature is α0, the unit sheet length of the sheet conveyed per pulse at low temperature is α1, and the unit sheet length is conveyed per pulse at high temperature. The unit sheet length of the sheet to be printed is α2.

  Further, for each paper length L0n (= α0 × Pn), L1n (= α1 × Pn) and L2n (= α2 × Pn), the motor 51 is rotated by the same number of pulses P = Pn without using the temperature correction value. It means the length of paper that is sometimes transported (paper length).

  Now, when the motor 51 rotates by the same number of pulses P = Pn in the high temperature, normal temperature, and low temperature states, the paper RP of the roll paper 40 conveyed by the conveyance roller 53 is as shown in FIG. Furthermore, the sheet length L1 at low temperature, the sheet length L0 at room temperature, and the sheet length L2 at high temperature, the sheet length L1 at low temperature is shorter than the sheet length L0 at room temperature by a length La, and at high temperature. The sheet length L2 is longer than the sheet length L0 at normal temperature by a length Lb. Here, it is assumed that the paper length L0 is a length corresponding to the target paper length.

  As described above, the paper lengths L1 and L2 of the paper RP are different from the paper length L0 (target paper length) by, for example, the length La and the length Lb depending on each environment (each temperature such as high temperature, normal temperature, and low temperature). As such, it will vary. In addition, as the target paper length at normal temperature is longer, that is, as the paper length L0 of the paper RP is longer, the respective values of the length La and the length Lb become larger.

  This is because the outer diameter D of the transport roller changes according to the change in temperature, and the unit paper length α changes due to the change of the outer diameter D of the transport roller. As shown, the cause is that the pulse number P is obtained with the unit paper length α as a constant value.

  That is, as described above, the outer diameter of the transport roller at a temperature higher than a reference temperature (for example, at normal temperature) is larger than the outer diameter of the transport roller at the reference temperature. As a result, when one pulse signal is supplied to the motor 51, the unit sheet length α2 at the time of high temperature in the sheet conveyed per pulse is longer than the unit sheet length α0 at the reference temperature. Thereby, the paper length L2 becomes longer than the paper length L0.

  On the other hand, the outer diameter of the conveyance roller at a temperature lower than a reference temperature (for example, at normal temperature) is smaller than the outer diameter of the conveyance roller at the reference temperature, and as a result, the unit sheet length α1 at low temperature is As a result, the sheet length L1 becomes shorter than the sheet length L0.

  Therefore, in the present embodiment, the unit sheet length α is corrected according to the change in temperature, and the pulse number P is obtained using the corrected unit sheet length α. This is because the number of pulses P reflects the value of the outer diameter D of the conveying roller that changes according to the change in temperature, in other words, the number of pulses P reflects the value of the unit sheet length α that changes according to the change in temperature. Means seeking.

Specifically, for example, when it is desired to make the paper length L1 at the low temperature equal to the paper length L0 at the normal temperature, the temperature correction value δ1 obtained by calculating the following equation 4 is used. In order to make the sheet length L2 at the same time and the sheet length L0 at the normal temperature equal, the temperature correction value δ2 obtained by calculating the following equation 5 may be used.
(Equation 4)

(Α1 + δ1) = α0, that is, δ1 = α0−α1
(Equation 5)

    (Α2 + δ2) = α0, that is, δ2 = α0−α2

  Here, the unit sheet lengths α0, α1, and α2 can be obtained based on the sheet lengths L0, L1, and L2 obtained by actual measurement and the known pulse number P.

  For example, in the example shown in FIG. 5, the unit sheet length α0 can be obtained by dividing the sheet length L0 (= L0n), which is an actual measurement value, by the number of pulses P (= Pn), which is a known value. Other unit sheet lengths can be obtained in the same manner as the unit sheet length α0.

  By calculating the unit sheet lengths obtained in this way by substituting into the above equations 4 and 5, the temperature correction value δ1 and the temperature correction value δ2 can be obtained.

  Here, a method of obtaining the actual number of pulses using the temperature correction value thus obtained will be described.

  For example, in the example shown in FIG. 5, in order to obtain a paper length L0n equivalent to that at normal temperature at high temperatures, L0n = α2 × P2 is required. Therefore, the necessary number of pulses P2 is P2 = L0n / α2. Become.

  Here, since α2 = α0−δ2 is obtained from the above equation 5, the number of pulses P2 at a high temperature is P2 = L0n / (α0−δ2) using the temperature correction value δ2.

  Similarly, the number of pulses P1 required to obtain a paper length L0n equivalent to that at room temperature at low temperatures is P1 = L0n / (α0−δ1) using the temperature correction value δ1. Note that the number of pulses P1 is the number of pulses corresponding to the intersection of the line length obtained by extending the line segment indicated by the symbol L1 in FIG. 5 and the sheet length L0n (P1> Pn> P2 is established).

  Therefore, the number of pulses P necessary to obtain the paper length L is expressed by the above formula 3 when the temperature correction value δ is used.

  By the way, information in which each temperature at normal temperature, low temperature, and high temperature is associated with each temperature correction value obtained as described above is stored in advance in the ROM 112 in the control unit 110 in a table format, for example. Will be.

  FIG. 7 shows an example of a temperature correction table in which each temperature is associated with each temperature correction value.

  Here, for example, the high temperature is 29 [° C.] or more, the normal temperature is 15 to 28 [° C.], and the low temperature is 14 [° C.] or less. Moreover, let the temperature of the range of 15-28 [degreeC] be a reference temperature. In addition, these temperature values are examples, and are not limited to those values.

  Then, the control unit 110 corrects the unit sheet length α based on the detected temperature from the temperature sensor 70 and the temperature correction table 400 shown in FIG. 7, and finally corrects the number of pulses P.

  For example, in the case where the roll paper 40 is fed from the roll paper feeding device 20, the control unit 110 detects the temperature correction table when the temperature detected by the temperature sensor 70 is 30 ° C. The temperature correction value δ2 is extracted with reference to 400, the unit paper length α is corrected based on the temperature correction value δ2, and the pulse number P is obtained based on the corrected unit paper length α.

  Next, control processing of roll paper cutting timing by the control unit 110 of the roll paper feeding device 20 will be described with reference to FIG.

  FIG. 8 is a flowchart showing the processing procedure of the cutting timing control processing.

  Here, a case of copying (in the case of a copy function) will be described as an example. First, when an operator sets, for example, an A0 size document (long document) on the document table and performs a copy start operation using the operation unit, the controller 300 selects a roll paper corresponding to the document size. Therefore, a paper feed instruction (paper feed command) for the roll paper 40 is output to the control unit 110 corresponding to the roll paper feed device 20 in which the A0 size roll paper 40 is accommodated.

  In this case, for example, the controller 300 outputs a paper feed instruction to the control unit 110 including information indicating the document size. For example, information indicating the length of the long original in the sub-scanning direction corresponding to the length in the width direction (length in the main scanning direction) of the long original detected when scanning the original (long original). The sheet feed instruction is output to the control unit 110.

  The control unit 110 of the roll paper feeding device 20 determines whether or not there is a paper feed instruction from the controller 300 (step S101). If there is, the detected temperature (temperature information) output from the temperature sensor 70, that is, the temperature value is acquired (step S102).

  Next, the control unit 110 obtains a temperature correction value δ based on the acquired detected temperature and the temperature correction table 400 shown in FIG. 7 (step S103), and changes in the environment (temperature) using the temperature correction value δ. The number of pulses P corresponding to is obtained (step S104).

  Here, a specific example will be described. It is assumed that information indicating the unit sheet length α0 at the reference temperature (normal temperature = 15 to 28 [° C.]) is stored in the ROM 112 in the control unit 110. When the temperature value acquired from the temperature sensor 70 is, for example, 30 [° C.], the control unit 110 extracts the temperature correction value δ2 corresponding to the temperature value (30 [° C.]) from the temperature correction table 400. The control unit 110 then sets the temperature correction value δ2, the unit paper length α0 read from the ROM 112, the length in the sub-scanning direction of the original (A0 size long original) acquired from the controller 300 (the target paper length, The number of pulses P2 is obtained by substituting each value of (paper length L0) into the above equation 3 and calculating.

  The controller 110 that has obtained the pulse number P corresponding to the environmental change in this manner outputs a start instruction signal indicating a motor drive start instruction to the motor driver 120 (step S105).

  The motor driver 120 that has received the start instruction signal supplies a pulse signal having a predetermined frequency to the motor 51 under the control of the control unit 110. This pulse signal is also input to the control unit 110.

  If the motor driver 120 continues to supply a pulse signal of a predetermined frequency to the motor 51 until it receives a motor drive stop instruction signal from the control unit 110, the motor 51 rotates based on the input pulse signal ( Rotation operation according to the step angle). Accordingly, the transport roller 53 rotates via the gear train 52, and the roll paper 40 is transported.

  By the way, when the control unit 110 that has output the start instruction signal to the motor driver 120 receives (acquires) the pulse signal output from the motor driver 120 (step S106), the control unit 110 outputs the number of received pulse signals (number of pulses). Count up (step S107).

  Next, the control unit 110 determines whether or not the count value has reached the number of pulses P2 obtained in step 104 (step S108). If the count value has not reached the number of pulses P2, the above step is performed. Returning to S106, if the count value reaches the number of pulses P2, a stop instruction signal indicating a motor drive stop instruction is output to the motor driver 120 (step S109), and the paper should be cut to the cutter 60. A disconnection instruction signal is output (step S110).

  As a result, the motor driver 120 that has received the stop instruction signal stops supplying the pulse signal to the motor 51, so that the rotation operation of the motor 51 is stopped, and accordingly, the rotation operation of the transport roller 53 is also stopped.

  Then, the cutter 60 that has received the cutting instruction signal from the control unit 110 cuts the A0 size roll paper 40. That is, when the roll paper fed by the transport roller 53 reaches the length of the original (A0 size long original) in the sub-scanning direction (that is, the target paper length), the roll paper is fed to the roll paper feeder 20. It is cut by the cutter 60 inside. The sheet cut in this way is finally discharged from the discharge port 17 of the image forming apparatus main body 2.

  As a result, a sheet RP having a sheet length L0 (target sheet length) is obtained as shown in FIG. 9 as an image forming result when the image forming process is performed at a temperature of 30 [° C.].

  Further, when the temperature value acquired from the temperature sensor 70 is a temperature value of, for example, 20 [° C.] or 10 [° C.], the number of pulses P is determined in the same manner as described above. That is, when the temperature value is 20 [° C.], the pulse number P0 is obtained without correction (temperature correction value = 0), and when the temperature value is 10 [° C.], the pulse number P1 is calculated with the temperature correction value δ1. Desired. The pulse signals corresponding to the number of pulses P0 and P1 are supplied to the motor 51 and then cut, and in either case, as a result of image formation, a sheet having a sheet length L0 (target sheet length) as shown in FIG. RP will be obtained.

  Here, the relationship of “P1> P0> P2” is established in the pulse numbers P0, P1, and P2 corresponding to the normal temperature, the low temperature, and the high temperature.

  As described above, in the present embodiment, the control unit 110 converts the detected temperature (temperature value), the rotation information (unit paper length α) of the transport roller 53, and the temperature correction information (temperature correction value δ) related to the rotation information. Based on the cutting timing (the number of pulses P, that is, when the rotation operation of the motor to which the pulse signal corresponding to the number of pulses P is supplied) is obtained, the cutter 60 is based on the information (pulse number P) indicating the obtained cutting timing. On the other hand, control is performed to cut the roll paper.

  Specifically, when the detected temperature (for example, 10 [° C.]) is lower than the reference temperature (for example, 15 to 28 [° C.]), the control unit 110 determines the cutting timing ( For example, the number of pulses P1) is made slower than the cutting timing (for example, the number of pulses P0) in the state of the reference temperature (relationship of P1> P0), while the detected temperature (for example, 30 [° C.]) is the reference temperature (for example, 15). When it is higher than the cutting timing (for example, the number of pulses P2) in the state of the detected temperature, the cutting timing (for example, the number of pulses P0) in the state of the reference temperature is made earlier (for example, the number of pulses P0). P2 <P0 relationship).

  With such control, even when the outer diameter of the transport roller changes with environmental changes such as temperature, the length of the paper (paper length) after the roll paper is cut is set to the target paper length ( For example, the length of the long document in the sub-scanning direction) can be set, and variations in the paper length can be suppressed.

  In the above description, the processing in the case of the copying function of the image forming apparatus has been described. However, in the case of printing (in the case of the printing function), the same processing as in the case of the copying function is performed.

  In this case, for example, the image forming apparatus and a document processing apparatus such as a computer are connected via a communication line, and the image forming apparatus receives document information from the document processing apparatus and performs image forming processing based on the document information. Will be executed.

  At that time, the controller recognizes the document size (vertical length and horizontal length, or the length in the main scanning direction and the length in the sub-scanning direction), which is a part of the attribute information included in the received document information. In order to select a roll paper corresponding to the original size, a paper feed instruction (feed instruction) including information indicating the original size is sent to the control unit of the control system corresponding to the relevant roll paper feeder. ) Is output.

  In the present embodiment, the temperature correction value corresponding to the detected temperature is extracted from the temperature correction table, and the calculated temperature correction value, the target sheet length, and the unit sheet length at the reference temperature are substituted into the above Equation 3 for calculation. By doing so, the number of pulses P is obtained, but the present invention is not limited to this and may be as follows.

  That is, the sheet length L of the sheet after actual cutting when the pulse number P of the pulse signal to be supplied to the motor is changed at a predetermined pulse number interval at each of normal temperature, low temperature, and high temperature is sampled. (Actual measurement). Then, for each temperature, the relationship between the sheet length L and the pulse number P of the sheet after cutting is plotted to obtain the characteristics. An example of information (graph) showing the relationship between the paper length L and the number of pulses P is shown in FIG.

  In FIG. 10, the line segment indicated by reference numeral L10 indicates the relationship between the sheet length of the sheet at normal temperature and the pulse number, and the line segment indicated by reference numeral L11 indicates the sheet length and pulse number of the sheet at low temperature. The line segment indicated by reference numeral L12 indicates the relationship between the sheet length of the sheet and the number of pulses at a high temperature.

  Here, when it is desired to obtain the sheet length L0 corresponding to the target sheet length, the control unit 110 identifies the corresponding line segment from the characteristics shown in FIG. 10 based on the temperature value acquired from the temperature sensor 70, and this identification. The number of pulses when the sheet length is L0 is obtained using the obtained line segment.

  Specifically, the line segment L10 is specified at room temperature, and the pulse number P0 corresponding to the paper length L0 is obtained using this line segment L10. Similarly, a line segment L11 is specified at a low temperature, and the pulse number P1 corresponding to the paper length L0 is obtained using this line segment L11. The line segment L12 is specified at a high temperature, and the pulse number P2 corresponding to the paper length L0 is obtained using the line segment L12.

  In this way, the pulse number of the pulse signal to be supplied to the motor may be the pulse number P0 at room temperature, whereas the pulse number P1 is higher than the pulse number P0 at low temperature, and the pulse number P2 is high at high temperature. Less than P0. In other words, the cutting timing is changed according to the change in temperature.

  Further, in the present embodiment, the temperature correction table 400 shown in FIG. 7 is information in which three temperature states of high temperature, normal temperature, and low temperature are associated with each temperature correction value. Without being limited thereto, the following may be used.

  That is, the sheet length L of the sheet in each of four or more temperature states is sampled, and a temperature correction table is created based on the sampling result. The unit sheet length α is corrected using this. Thereby, the accuracy of the sheet length of the sheet after cutting can be increased, and variations in the sheet length can be further suppressed.

  For example, in the temperature range of 0 to 40 [° C.], the same number of pulses P for each temperature value at a predetermined temperature value interval of 0.5 [° C.], 1 [° C.], 5 [° C.], etc. The paper length L of the cut paper when the pulse signal is supplied to the motor is sampled (actually measured). Further, for example, 20 to 25 [° C.] is set as a reference temperature (room temperature), and a reference unit sheet length is set as a unit sheet length α0.

  As described above, since the unit sheet length α corresponding to the temperature value is obtained based on the sampled sheet length L and the number of pulses P, each unit sheet length α and unit sheet length α0 corresponding to each temperature value are obtained. Based on the above, each temperature correction value δ corresponding to each temperature value is obtained. Then, a temperature correction table as shown in FIG. 7 is created by associating each temperature value with each temperature correction value.

  Furthermore, in the present embodiment, the motor is a stepping motor, but the present invention is not limited to this, and the type of motor is not limited as long as the motor can drive a conveyance roller such as a DC motor.

  In this case, for example, an encoder is provided on the rotating shaft of the DC motor, or an encoder is provided on the shaft of the conveying roller. The pulse signals output from these encoders are input to the control unit of the roll paper feeding device.

  By the way, based on the number of pulses of the pulse signal output from the encoder and the outer diameter of the conveying roller, the sheet length (unit sheet length) α of the sheet conveyed by the conveying roller per pulse output from the encoder is calculated. I can know. Also in this case, the above formulas 1 to 5 can be basically applied.

  Therefore, when an encoder is provided on the rotating shaft of the DC motor, the control unit 110 rotates the DC motor so that the number of pulse signals output from the encoder per one rotation of the motor changes according to a change in temperature. Can be controlled.

  On the other hand, when the encoder is provided on the shaft of the transport roller, the control unit 110 rotates the DC motor so that the number of pulse signals output from the encoder per rotation of the transport roller changes according to the temperature change. Can be controlled.

  As described above, according to the present embodiment, the unit sheet length is corrected according to the detected temperature detected by the temperature sensor provided in the vicinity of the roll paper feeding device, and the corrected unit sheet length and target are corrected. Since the number of pulses of the pulse signal to be provided to the motor is obtained based on the paper length (for example, the length of the long original in the sub-scanning direction) (the cutting timing is obtained), The length of the paper after cutting can be set as the target paper length, and variations in the length of the paper can be suppressed.

  The present invention is applied to an image forming apparatus that prints an image on roll paper, such as an image forming apparatus having a copying function or a printing function, and an image forming apparatus having a copying function and a printing function (an image forming apparatus as a so-called multifunction machine). be able to.

  The present invention is also applied to an image forming apparatus that is connected to a communication line such as a network to which a document processing apparatus for creating a document is connected, and that prints an image on roll paper based on document information from the document processing apparatus. Can do.

1 is a perspective view illustrating an appearance of an image forming apparatus according to an embodiment of the present invention. It is sectional drawing which shows the AA cross section of the image forming apparatus shown in FIG. FIG. 3 is a configuration diagram illustrating a configuration of a conveyance roller unit in a roll paper feeding device provided in the image forming apparatus according to the present embodiment. 3 is a configuration diagram illustrating a control system of a roll paper feeding device provided in the image forming apparatus according to the present embodiment. FIG. FIG. 6 is a diagram for explaining variation in the length of a sheet when the number of pulses is constant with respect to the sheet as an output result of image formation of the image forming apparatus according to the present embodiment, and the number of pulse signals supplied to a motor 6 is a graph showing the relationship between the length of the paper conveyed by the conveyance roller and the length of the paper conveyed by the conveyance roller. FIG. 6 is a diagram for explaining a sheet feed length in each temperature state when the number of pulse signals supplied to a motor during image formation of the image forming apparatus according to the present embodiment is constant. FIG. 6 is a diagram illustrating an example of a temperature correction table that is referred to when a unit sheet length is corrected during the cutting timing process of the image forming apparatus according to the present embodiment. 6 is a flowchart showing a processing procedure of cutting timing control processing of the image forming apparatus according to the present embodiment. FIG. 6 is a diagram for explaining a sheet feed length in each temperature state when the number of pulse signals supplied to a motor is changed according to each temperature during image formation of the image forming apparatus according to the present embodiment. . FIG. 6 is a diagram for explaining how to obtain the number of pulses necessary to obtain a target sheet length of a sheet as an output result of image formation of the image forming apparatus according to the present embodiment, and the number of pulse signals supplied to a motor 6 is a graph showing the relationship between the length of the paper conveyed by the conveyance roller and the length of the paper conveyed by the conveyance roller.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Image forming apparatus main body 3 Case 10 Image forming part (image forming means)
20, 30 Roll paper feeding device 40, 41 Roll paper 42, 50 Conveyance roller unit 43, 60 Cutter (cutting means)
51 Motor 52 Gear train 53 Conveying roller 54 Idler rollers 70, 80 Temperature sensor (temperature detecting means)
100, 200 Roll paper feeding device control system 110 Control unit (control means)
111 CPU
112 ROM
113 RAM
120 motor driver 300 controller

Claims (6)

A transport roller for transporting the roll paper stored in the paper feeding device toward an image forming unit that executes image forming processing;
Cutting means for cutting the roll paper conveyed by the conveyance roller;
Temperature detecting means for detecting the temperature in the vicinity of the conveying roller;
Control means for controlling the cutting timing of the roll paper by the cutting means according to the detected temperature indicating the temperature detected by the temperature detecting means;
An image forming apparatus comprising: The control means includes
When the detected temperature is lower than the reference temperature, the cutting timing in the state of the detected temperature is made later than the cutting timing in the state of the reference temperature, while the detected temperature is compared with the reference temperature. If it is high, the cutting timing in the detected temperature state is made earlier than the cutting timing in the reference temperature state,
The image forming apparatus according to claim 1. The control means includes
A cutting timing is obtained based on the detected temperature, rotation information of the conveying roller, and temperature correction information related to the rotation information, and the roll paper is to be cut to the cutting unit based on information indicating the obtained cutting timing. Control,
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The transport roller is
It rotates following the rotation of a pulse-controlled motor,
The control means includes
Based on the detected temperature, the rotation information of the transport roller, and the temperature correction information related to the rotation information, the number of pulses indicating the number of pulse signals to be provided to the motor as information indicating the cutting timing is obtained. Controlling the cutting means to cut the roll paper based on the number of pulses obtained,
The image forming apparatus according to claim 1, wherein the image forming apparatus is an image forming apparatus. The rotation information of the transport roller is
Information indicating the paper length of the roll paper obtained based on the outer diameter information of the conveying roller and conveyed according to the rotation of the conveying roller per predetermined unit time,
The image forming apparatus according to claim 3, wherein the image forming apparatus is an image forming apparatus. The temperature correction information is
The length of the roll paper conveyed according to the rotation of the conveying roller per predetermined unit time in the detected temperature state is set to the rotation of the conveying roller per predetermined unit time in the reference temperature state. It is a correction value for correcting to the paper length of the roll paper conveyed accordingly.
The image forming apparatus according to claim 3, wherein the image forming apparatus is an image forming apparatus.

Images